Science, Faculty of
Zoology, Department of
DSpace
UBCV
Gainer, Robert Stewart
Master of Science - MSc
University of British Columbia
Anthrax was associated with the death of a large number of animals in the Selous Game Reserve. The significance of this disease to the populations of these animals was of concern to the reserve's management. Models are presented of the evolutionary effects of four host-pathogen relationships. Based on a demographic study of the wildebeest and a study of the characteristics of the disease, the anthrax-wildebeest relationship was compared with the models. The results of the study indicate that even though anthrax was responsible for the death of approximately 10% of the wildebeest, it had a balanced relationship with the population. The pathogen was probably an asset to its host population's continued existence rather than a hazard, as its mortality was associated with animals that appeared to be a disadvantage to the wildebeest population. If the management of the reserve wished to reduce the occurrence of anthrax, it is suggested that they reduce the number of wildebeest older than calves. In addition to maintaining a stable age configuration, this would improve the quality of the habitat, reduce the number of animals in poor condition, and thus reduce the number dying of anthrax. In addition, I deal with several other topics in Appendices.
E BOLE OF ANTHBAX IN THE POPULATION BIOLOGY OF WILDEBEEST IN THE SELOUS GAME BESEBVE by Bobert Stewart Gainer D.V.M., University of Saskatchewan, 1971 A THESIS SUBMITTED IN PABTIAL FULFILLMENT OF THE BEQUIBEMENTS FOB THE DEGBEE OF MASTEB OF SCIENCE i n THE FACULTY OF GBADUATE STUDIES (Department of Zoology) He accept t h i s t h e s i s as conforming to the required standard THE UNIVEBSITY OF BBITISH COLUMBIA February, 1979 (c) Bobert Stewart Gainer , 1979 I n p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f t h e r e q u i r e m e n t s f o r an a d v a n c e d d e g r e e a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , I a g r e e t h a t t h e L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e a n d s t u d y . I f u r t h e r a g r e e t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by t h e Head o f my D e p a r t m e n t o r by h i s r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . D e p a r t m e n t o f The U n i v e r s i t y o f B r i t i s h C o l u m b i a 2075 W e s b r o o k P l a c e V a n c o u v e r , C a n a d a V6T 1W5 6 B P 7 5 - 5 1 1 E ABSTRACT Anthrax was a s s o c i a t e d with the death of a l a r g e number of animals i n the Selous Game Reserve. The s i g n i f i c a n c e o f t h i s d i s e a s e t o the p o p u l a t i o n s of these animals was o f concern t o the .reserve*s management* Models are presented of the e v o l u t i o n a r y e f f e c t s o f fo u r host-pathogen r e l a t i o n s h i p s - Based on a demographic study of the wil d e b e e s t and a study of the c h a r a c t e r i s t i c s of the d i s e a s e , the anthrax-wildebeest r e l a t i o n s h i p was compared with the models. The r e s u l t s of the study i n d i c a t e t h a t even though anthrax was r e s p o n s i b l e f o r the death of approximately 10% of the wi l d e b e e s t , i t had a balanced r e l a t i o n s h i p with the p o p u l a t i o n . The pathogen was probably an a s s e t to i t s host p o p u l a t i o n ' s continued e x i s t e n c e r a t h e r than a hazard, as i t s m o r t a l i t y was a s s o c i a t e d with animals that appeared to be a disadvantage to the wildebeest p o p u l a t i o n . I f the management of the r e s e r v e wished t o reduce the occurrence of anthrax, i t i s suggested t h a t they reduce the number o f wi l d e b e e s t o l d e r than c a l v e s . , I n a d d i t i o n to m a i n t a i n i n g a s t a b l e age c o n f i g u r a t i o n , t h i s would improve the q u a l i t y o f the h a b i t a t , reduce the number of animals i n poor c o n d i t i o n , and thus reduce the number dying of anthrax. In a d d i t i o n , I d e a l with s e v e r a l other t o p i c s i n Appendices. i i i TABLE OF CONTENTS ABS!TI£ACT •*-•*•• • • • > . * ^ « i ^ « ' « • • « • >.• > m X i ACKNOWLEDGEMENTS ........ x i INTEODUCTION . . . . . . . . . . . . . . . . . . . . . . 1 Study Area ............................................. 8 MATERIALS AND METHODS 13 . Beconnaissance .................. .................... 13 Ground Transects . . . . . . . . . . . . . . . . . . . . . . . . 1 4 A e r i a l Surveys ............................... 15 Shot Sample ......................................... 15 Picked-up Skull C o l l e c t i o n 16 Socio-ecological Organization ....................... 16 Population Size ..................................... 17 L i f e Table .......................................... 18 Pattern Of Mortality ...... v . . . - . . . ^ - - 19 Reconnaissance .................. .................... 21 Age And Sex Composition - ,m i 9 :m. ,•.,>•«***•<-«•«•., . . . . • • . 22 Socio-ecological Organization ....................... 31 Population Size ..................................... 40 L i f e Table .......................................... 41 Mortality ........................................... 44 DISCUSSION:: • .-. . .;. » . . . ..••.•« •»•>•". ••• ••• ••• 4-• -••.•••>''*• • • •• «• • 5 2 Population C h a r a c t e r i s t i c s .......................... 52 Ch a r a c t e r i s t i c s Of Anthrax .......................... 54 Anthrax-wildebeest Belationship ..................... 59 i v MANAGEMENT STRATEGY ..^ . ......... . 62 LITERATORE CITED ........... ................ 64 APPENDIX I. ISOLATION OF BACILLUS ANTHRACIS USING MOOSE INNOCULATION ...........................,... ............ 70 APPENDIX I I . REPRODUCTION OF FEMALE WILDEBEEST AND. I MPA LA . 76 APPENDIX III.; THE INTERPRETATION OF PREGNANCY FBOM : HILDEBEEST OVARIES ........... ... ..... 91 APPENDIX IV. AGE DETERMINATION METHODS FOR WILDEBEEST 105 APPENDIX V. THE ESTIMATION OF IILDEBEEST AND IMPALA DENSITIES USING VEHICLE TRANSECTS ..... 123 APPENDIX VI. A SURVEY OF THE PARASITES, DISEASES, AND ANOMALIES IN ANIHALS OF THE SELOUS; AND THEIR MANAGEMENT CONSIDERATIONS 134 LIST OF TABLES v QTable 1 . The p r o p o r t i o n s of the age and sex c a t e g o r i e s i n the t r a n s e c t p o p u l a t i o n ..... 23 Table 2. The age and sex of t h e animals i n the s h o t Table 3. The sex of the picked-up s k u l l s i n the r e g i o n s with the non-predatory m o r t a l i t y and i n the r e g i o n without t h i s m o r t a l i t y ...... 28 Table 4. The age and sex of t h e picked-up s k u l l s ... 29 Table 5- The age and sex of the combined shot sample and picked-up s k u l l c o l l e c t i o n and t h e i r percentage p r o p o r t i o n s .................... 30 Table 6. The estimated year o f death of the picked-up Appendix I I . Table 1. The pregnancy r a t e of Selous wildebeest from the v a r i o u s sources of pregnancy i n f o r m a t i o n , and the pregnancy r a t e of other wildebeest p o p u l a t i o n s .................... 84 Appendix IV. Table 1., The enamel height measurements a s s o c i a t e d with the age p r e d i c t e d u s i n g i n c r e m e n t a l l i n e s and the 95% c o n f i d e n c e l i m i t s of the age c l a s s p r e d i c t e d using enamel height v i measurements ..... 114 Appendix V. Table 1. The number of t r a n s e c t o b s e r v a t i o n s a t each s i g h t i n g d i s t a n c e c a t e g o r y and the a s s o c i a t e d parameters ............... ...... 127 Appendix VI. Table 1. The prevalence and l e v e l of i n f e c t i o n o f f r e g u e n t l y encountered p a r a s i t e s i n the more f r e q u e n t l y examined host s p e c i e s . ......... 140 Table 2. The t i c k s p e c i e s c o l l e c t e d from ungulate h o s t s . ,-. . ,. ... ..... ... , v, --«- * 143 Table 3. The bot f l y s p e c i e s c o l l e c t e d ............. 144 Table 4. The s p e c i e s of S e t a r i a c o l l e c t e d from ungulates' ... v.. ... ... ..... ................. 1.52 Table 5. The i n t e s t i n a l nematodes c o l l e c t e d ........ 154 Tabl e 6. The r e s u l t s of the HcBaster counts of wild e b e e s t , impala, and b u f f a l o f e c e s ..... 156 Table 7. A comparison of f e c a l counts from t h i s study with other s t u d i e s ........................ 157 Table 8. The d i s t r i b u t i o n of measle c y s t s i n muscle r e g i o n s of s e v e r a l ungulate s p e c i e s ....... 159 Table 9. The weights of muscle r e g i o n s f o r s e v e r a l s p e c i e s o f Selous animals ................. 161 Table 10. Serological r e s u l t s from the Central Veterinary Laboratory ..................... 167 Table 11. Serological results from Kabate Veterinary Laboratory ................................ 168 Table 12. S e r o l o g i c a l r e s u l t s from the East African Veterinary Organization ..... .......... .... 172 v i i i LIST OF FIGURES F i g u r e 1. ft t y p i c a l member o f the Nyasa race of the blue wildebeest demonstrating the f a c i a l chevron ................................. 2 F i g u r e 2. The f o u r h a b i t a t types i n the r e g i o n o f th e study area .......................... 10 F i g u r e 3. The t y p i c a l miombo i n the r e g i o n of the F i g u r e 4 . a t y p i c a l shallow s u r f a c e concentrated type waterhole dur i n g the wet season .... 2 F i g u r e 5. The p r o p o r t i o n s of the age and sex c a t e g o r i e s i n the t r a n s e c t p o p u l a t i o n ... 24 F i g u r e 6. The p r o p o r t i o n s of the three d i f f e r e n t types of groups observed i n the t r a n s e c t F i g u r e 7. The r e l a t i o n s h i p between the s i z e o f a herd and i t s c a l f p r o p o r t i o n ............ 36 F i g u r e 8. The p r o p o r t i o n of the age and sex c a t e g o r i e s i n the mixed herds ........... 38 F i g u r e 9. The number of wildebeest i n the s h o r t g r a s s r e g i o n as determined from t r a n s e c t and a e r i a l e s t i m a t e s .................... 42 F i g u r e 10. The p o p u l a t i o n 1 s l i f e t a b l e ............. 45 F i g u r e 11. The m o r t a l i t y curve d e r i v e d from the l i f e i x Appendix I I . F i g u r e 1. Hugget and Widdas r e g r e s s i o n of wildebeest f e t a l weights ........................... 79 F i g u r e 2. Hugget and Widdas r e g r e s s i o n of impala f e t a l weights 82 Appendix I I I . F i g u r e 1. R e p r e s e n t a t i v e s of the o v a r i a n s t r u c t u r e s 93 F i g u r e 2. A yellow pigmented scar prepared using the f r o z e n t i s s u e method .................... 97 F i g u r e 3. A brown pigmented s c a r prepared using the f r o z e n t i s s u e method .............. ...... 97 Appendix IV. F i g u r e 1. A f i r s t molar from a 12 month o l d animal 107 F i g u r e 2. A f i r s t molar from a 24 month o l d animal 107 F i g u r e 3. A f i r s t molar with the maximum number of i n c r e m e n t a l l i n e s ....................... 107 F i g u r e 4. The r e g r e s s i o n l i n e between enamel he i g h t and cementum l i n e counts ................ 112 F i g u r e , 5 . The schedule f o r the e r u p t i o n and wear of m a x i l l a r y t e e t h ......................... 115 F i g u r e 6. Comparison of the r e g r e s s i o n i n F i g u r e 4 with a t o o t h wear model ................. 117 Appendix V. X F i g u r e 1. The d i s t r i b u t i o n of the s i g h t i n g d i s t a n c e s of wildebeest and impala o b s e r v a t i o n s ... 128 Appendix VI. F i g u r e 1. The prevalence of pentastomid l a r v a e i n t h e d i f f e r e n t ungulate s p e c i e s .......... 146 F i g u r e 2. The prevalence of raeasle c y s t s i n the d i f f e r e n t ungulate s p e c i e s 146 F i g u r e 3. The d i s t r i b u t i o n of measle c y s t s , on a weight b a s i s , a c c o r d i n g t o muscle r e g i o n s 146 F i g u r e 4. An i l l u s t r a t i o n of how p a r a s i t i c i n f e c t i o n s are obtained from c l o s e w i l d animal a s s o c i a t i o n s ..................... 193 ACKNOWLEDGEMENTS T h i s p r o j e c t i s the combined e f f o r t of f o u r o r g a n i z a t i o n s : The U n i v e r s i t y of B r i t i s h Columbia, Tanzania Game D i v i s i o n , Danish Government A i d , and the Canadian U n i v e r s i t y S e r v i c e s Overseas.: I am indeed f o r t u n a t e t o have had the s u p e r v i s i o n of Dr., I . HcTaggart-Cowan a t the U n i v e r s i t y of B r i t i s h Columbia. Dr. P.A. L a r k i n as well has c o n t r i b u t e d e x t e n s i v e l y to the p r e p a r a t i o n o f t h i s t h e s i s . T h e i r accommodation o f the v e t e r i n a r y theme i s testimony to t h e i r broad-minded approach t o b i o l o g y . In a d d i t i o n , the q u a l i t y of my t h e s i s g r e a t l y b e n e f i t e d from my acquaintance and correspondence with Drs. V o s s i e de Vos, G.B. Van Ness, H. Ebedes, and A. Provost; and Mr. Pat Hemingway. Mwalimu Pat e s p e c i a l l y should be thanked f o r the d i r e c t i o n he gave most Canadian volunteer b i o l o g i s t s doing r e s e a r c h i n Tanzanian Game Reserves. Drs. E. McEwan and H.D. F i s h e r , Mr. F. Maurer and the s t a f f o f the B i o l o g y Data Center provided v a l u a b l e t e c h n i c a l and b i o m e t r i c a l a s s i s t a n c e a t the U n i v e r s i t y of B r i t i s h Columbia. Most of a l l , I am g r a t e f u l to the people of Tanzania f o r the p r i v i l e g e of having worked with them as a member of Game D i v i s i o n . A l l the f i e l d work I d i d i n c o n j u n c t i o n with l o y a l Game D i v i s i o n a s s i s t a n t s , i n c l u d i n g H a f u n d i i E. Goryama, S. Mpapa, M. Mkopoka, H. M a t a l i , and M. Mfaume. Mabwana A. Makungira and H.P. Desusso a s s i s t e d on o c c a s i o n as w e l l . I am e s p e c i a l l y g r a t e f u l t o Mzee Goryama f o r h i s e x t r a e f f o r t s i n the f i e l d . x i i Tanzania Game D i v i s i o n i s very conscious of the management p r a c t i c e s f i r s t advocated by F.C., Selous and C.J.P. Xonides. These men, the world*s two g r e a t e s t h u n t e r - m a t u r a l i s t s , l i v e d and d i e d i n the Selous Game Reserve. I t was t h e i r dream t h a t t h e natural, phenomena of the game r e g i o n s such as the Selous would be p r e s e r v e d f o r e v e r f o r d i s c r i m i n a t i n g h u n ters who are a l s o s t u d e n t s of n a t u r e . T h e i r two protegees, B.D. Nicholson and A. Rees, passed on these i d e a l s t o a l l who worked with them. My perserveranGe with t h i s study i s a t l e a s t p a r t i a l l y because I gained an a p p r e c i a t i o n of t h i s t r a d i t i o n from B r i a n N i c h o l s o n . S e v e r a l Game D i v i s i o n e x p e r t s advised and a s s i s t e d my performance o f the p o p u l a t i o n study. These i n c l u d e d Ron McLaughlin, B r i a n N i c h o l s o n , Dr. C l i v e Spinage, Pat Hemingway, Franc Mes, Graham Mutch, K e i t h Hodson, Terry S t i r r u p , Peter Lane, Gus Ashby, B i l l Spears, and Alan Rodgers. V i r t u a l l y a l l of the f a c i l i t i e s and m a t e r i a l s of the Miombo Research Center were p a i d f o r by the Danish Government. My p r o j e c t accounted f o r a l a r g e p r o p o r t i o n of t h i s very s u b s t a n t i a l ' a n d generous grant. The success o f the Miombo Research Center i s testimony t o the f o r e s i g h t and e f f o r t s of i t s d i r e c t o r , Mr. 8.A- Rodgers, The o r g a n i z a t i o n r e s p o n s i b l e f o r my p a r t i c i p a t i o n with Game D i v i s i o n r e s e a r c h i s the Canadian U n i v e r s i t y S e r v i c e s Overseas. The s p e c i f i c placement of a v e t e r i n a r i a n on a game r e s e r v e was due t o the e n t e r p r i s e of Andy Hamilton. My continued e x i s t e n c e i n t h i s c a p a c i t y was the r e s u l t o f the e x t r a e f f o r t of Wayne M u l l i n s . x i i i S e v e r a l members of the German Agency f o r T e c h n i c a l C ooperation a s s i s t e d my v e t e r i n a r y e f f o r t s - These i n c l u d e d Drs. R. Sachs, P.H. Hummel, H. Jakob, and B. Schiemann, Mr. £. Gorton, and Ms. E. Dehne and C. Wagner. Drs. J. Thorsen and D. K a r i u k i l , and Messrs. D.M- J e s s e t and F. Mes were a l s o of a s s i s t a n c e i n t h i s c a p a c i t y . I am e s p e c i a l l y g r a t e f u l f o r the e x t r a c o n s i d e r a t i o n of Budiger Sachs and h i s f a m i l y . Throughout t h i s l e n g t h y study, I was dependent upon s e v e r a l people f o r my accommodation and support. To two i n p a r t i c u l a r , Mrs. R.I. Rutzebeck and Bob Jones, I extend my s i n c e r e s t g r a t i t u d e . S e v e r a l people committed t o paper t h e i r f a i t h i n my a b i l i t y t o perform t h i s work. They i n c l u d e Drs. I . McT. Cowan, R. Sachs, W.A. Rodgers, A. Oeming, L. M i l l i g a n , C. W i l l i a m s , and F. Loew. I hope I have l i v e d up to t h e i r e x p e c t a t i o n s . Dr. R. C a r t e r c r i t i c i z e d and made r e v i s i o n s i n the grammar of Appendix VI. . And f i n a l l y , I thank C a t h e r i n e Lowe f o r her p a t i e n t , t o l e r a n t , and h i g h l y s k i l l e d p r e p a r a t i o n o f t h i s manuscript us i n g the O n i v e r s i t y • s computer. 1 INTRODUCTION g j l d e b e e s t (Connochaetes spp.) are a common c r e a t u r e of A f r i c a n p l a i n s . E s p e c i a l l y d u r i n g s e t seasons when they congregate i n open areas, t h e i r numbers can be i m p r e s s i v e . Probably the most s p e c t a c u l a r and w e l l known p o p u l a t i o n i s i n Tanzania's S e r e n g e t i N a t i o n a l Park. Two s p e c i e s of wildebeest are r e c o g n i z e d ( A n s e l l 1971); the black wildebeest or gnu j[C_. gnouj., and the blue or b r i n d l e d wildebeest |C. t a u r i n u s ) . The black wildebeest i s r e s t r i c t e d to a few southern A f r i c a n p r e s e r v e s , while the blue i s widely d i s t r i b u t e d over south, c e n t r a l , and e a s t A f r i c a . F i v e s u b s p e c i e s (or races) o f blue wildebeest are r e c o g n i z e d (Lydekker 1926, A n s e l l 1971). In southeast Tanzania, they are a woodland r a c e , (C. t . j o h n s t o n i ) , the Nyasa wi l d e b e e s t . I t has a l a r g e body s i z e , a r u f o u s brown c o l o r , and a dark beard and mane. E e g i o n a l d i f f e r e n c e s occur, but a white f a c i a l chevron ( F i g . 1) occurs more f r e g u e n t l y i n t h i s race than i n the other r a c e s . L a r g e l y because of r e g i o n a l d i f f e r e n c e s i n the degree and freguency of occurrence of the chevron, there i s c o n f u s i o n over the northern d i s t r i b u t i o n of the Nyasa race i n r e l a t i o n to the southern d i s t r i b u t i o n of the e a s t e r n white-bearded race ( C t , a l b o i u b a t u s ) (Sidney 1965, A n s e l l 1971) . On the b a s i s o f other d i s t i n g u i s h i n g morphological f e a t u r e s (Lydekker 1926), the d i v i d i n g l i n e between t h e i r d i s t r i b u t i o n s i s c o n s i d e r e d by myself and other Selous b i o l o g i s t s t o be c l o s e l y approximated by the Hami B i v e r i n the region of the Uakwavi, n o r t h e a s t of 2 Figure 1., The face of a t y p i c a l member of the Nyasa race of the blue wildebeest. The occurrence of the chevron i s more frequent i n t h i s race than in the other races, but there are considerable regional differences i n these frequencies. Figure 3 . Typical miombo woodland i n the region of the Miombo Research Center. This i s during the dry season after the t a l l coarse grass has been burnt. Figure 4 . k t y p i c a l shallow s u r f a c e - c o l l e c t i o n type of waterhole near theMiombo Research Center during the wet season. The waterholes were common i n the regions associated with anthrax. 4 Morogoro (Nicholson and Rodgers pers. comm.). In southeast Tanzania, wild animal p o p u l a t i o n s have been s t u d i e d f o r s e v e r a l years i n the Selous Game Reserve (Nicholson 1969). Since 1969, a non-predatory m o r t a l i t y was recog n i z e d i n s e v e r a l w i l d ungulate p o p u l a t i o n s i n the r e g i o n of the Miombo Research-Center (Stobart 1970). Most of t h i s m o r t a l i t y o c c u r r e d i n w i l d e b e e s t . Anthrax was diagnosed i n a sample of the v i c t i m s (Appendix I ) -Since the v i r t u a l e r a d i c a t i o n of r i n d e r p e s t , anthrax i s probably A f r i c a ' s most d e v a s t a t i n g d i s e a s e o f ungulates (Anon* 1971). Even though d i a g n o s t i c s e r v i c e s are sparse, the d i s e a s e has been diagnosed i n many game s a n c t u a r i e s (Lobry 1964, Cowan e t a l . 1967, Schiemann 1971, Vos 1973, Ebedes 1975, M o l l e l 1977). The most commonly a f f e c t e d s p e c i e s i s wildebeest (C. Cameron pe r s . comm.). Many s t u d i e s have surveyed and catalogued the p a r a s i t e s and d i s e a s e s o f w i l d animal p o p u l a t i o n s , but the r e a l concern of the agency r e s p o n s i b l e f o r the animals i s the s i g n i f i c a n c e o f a p a r a s i t e o r d i s e a s e t o the host p o p u l a t i o n . Pew s t u d i e s have addressed themselves to t h i s concern (Cowan 1974, T r a i n e r 1978, Davis 1978)., Such a study r e q u i r e s an examination of the i n t e r r e l a t i o n s h i p between host and pathogen p o p u l a t i o n s , and an a p p r e c i a t i o n o f e p i z o o t i o l o g y and p o p u l a t i o n a n a l y s i s (Herman 1969, Cowan 1974)., The u l t i m a t e e f f e c t s of a pathogen on a host s p e c i e s are the e v o l u t i o n a r y consequences of t h e i r r e l a t i o n s h i p . C o n s i d e r , f o r example, the f o l l o w i n g f o u r models of host-pathogen r e l a t i o n s h i p s . 5 The f i r s t two models are unbalanced; that i s , the host or the pathogen decreases the success of the other. Because an evolutionary struggle exists between the virulence of the pathogen and the resistance of the host, these relationships are usually transient (Cameron 1956, Self 1961, Sprent 1969). The f i r s t unbalanced model i s of a host whose resistance protects, i t from a pathogen's i n f e c t i o n s . The pathogen does not successfully survive t h i s r e l a t i o n s h i p . Examples are the host-s p e c i f i c i t y of most diseases that i n f e c t one host species, but not another. For instance, very few avian diseases i n f e c t mammals, or few bovine diseases i n f e c t equines. The second unbalanced model i s of a susceptible host i n which i n f e c t i o n by the pathogen reduces the success of the host. Unless the host's resistance evolves to prevent such an i n f e c t i o n , the host w i l l eventually be eliminated. Either way, the pathogen's species does not successfully . survive t h i s r e l a t i o n s h i p . Examples of t h i s model are recently introduced diseases. Rinderpest was o r i g i n a l l y a disease of European c a t t l e Bos taurus ( S c o t t 1964).,Introduced i n t o A f r i c a , i t was responsible for the e x t i n c t i o n of several wild ungulate populations (Spinage 1962). As i t was not able to maintain i t s e l f i n wild animal populations, i t disappeared when the disease was eliminated from surrounding populations of zebu (African) c a t t l e (Scott 1964). Myxomatosis was o r i g i n a l l y a disease of South American rabbits (Sylvilagus spp.). Introduced into A u s t r a l i a , i t almost eliminated the continent's enormous supply of European rabbits (Oryctolaqus cuniculns). The continued existence of rabbits in 6 Aus t r a l i a i s attributed to refugia i n which the disease was not transmitted and the continued existence of the disease i n the continent requires periodic reintroductions by humans ( Y u i l l 1970) . The meningeal worm fParelaphostrongylus tenuis) i s non-pathogenic and successful i n white-tailed deer (Odpcoileus V i r g i n i a n u s ) . I n other North American ungulates, i t causes severe d i s a b i l i t y and does not reproduce e f f i c i e n t l y . One reason white-tailed deer range has expanded and the range of other ungulates has contracted i n recent years i s thought to be because of t h i s parasite (Anderson 1971). The other two models are of balanced relationships i n which the success of one species does hot adversely a f f e c t the success of the other species (Cameron 1956). Because there i s no evolutionary struggle between the host's virulence and the pathogen's resistance, the r e l a t i o n s h i p tends to p e r s i s t . An evolutionary struggle may s t i l l be present, but t h i s i s to maximize the host's benefit from the pathogen without eliminating the pathogen (Sprent 1969) I f * over a long period of time, a pathogen has not eliminated i t s host and the host has not evolved a resistance that eliminates the pathogen, then the rela t i o n s h i p i s balanced. The t h i r d model i s of a balanced r e l a t i o n s h i p i n which the host i s f r e e from predation. In t h i s s i t u a t i o n , a pathogen can adversely a f f e c t i t s host's condition without adversely a f f e c t i n g the host's success. The most obvious i l l u s t r a t i o n s are domestic animals; whose predation, medical support, n u t r i t i o n , and reproduction are regulated by man. This i s one reason why 7 r i n d e r p e s t s u r v i v e d i n Europe but not i n A f r i c a n w i l d ungulates. Unpredated animals i n the w i l d a l s o show t h i s r e l a t i o n s h i p . L i v e r f l u k e s ( F a s c i o l a s p . ) , a domestc animal i n f e c t i o n , caused c h r o n i c d e b i l l i t a t i o n of an unpredated b l a c k - t a i l deer (Odocoileus hemionus) p o p u l a t i o n . When one of these animals was chased, i t d i e d as a consequence of the e x e r t i o n combined with the i n f e c t i o n (Cowan 1951). A c a l f elephant (Loxodonta a f r i c a n a ) s u r v i v e d with a c h r o n i c , long term d e b i l i t a t i o n (Gainer 1973) because, as a member of an e l e p h a n t group, i t was v i r t u a l l y immune t o p r e d a t i o n . Carmichael (1972) found t h a t i n u n g u l a t e s , the f e c a l egg count, and presumably the adverse e f f e c t s of the p a r a s i t e s , were higher i n areas where p r e d a t i o n was reduced. A f o u r t h model concerns a balanced r e l a t i o n s h i p i n which the host i s preyed upon. With t h i s model, the adverse e f f e c t s of a pathogen w i l l reduce i t s host's success by p r e d i s p o s i n g the host to p r e d a t i o n ; u n l e s s the host no l o n g e r c o n t r i b u t e s to i t s p o p u l a t i o n ' s success* There i s l i t t l e documented evidence f o r t h i s model, but E r r i n g t o n (1963) expressed e s s e n t i a l l y the same view i n t h a t he concluded t h a t members t h a t were of no consequence to a p o p u l a t i o n ' s success were marked f o r death by d i s e a s e and/or p r e d a t i o n . . In 1971, I undertook t o do a demographic study of the wildebeest p o p u l a t i o n a s s o c i a t e d with the anthrax m o r t a l i t y near the Hiombo Research Center. In the f i e l d , s e v e r a l members of the r e s e a r c h s t a f f a s s i s t e d my c o l l e c t i o n of t h i s i n f o r m a t i o n . From the a n a l y s i s of our m a t e r i a l , I assessed the e f f e c t of anthrax on the dynamics o f the wildebeest population.. 8 Based on the eff e c t s of anthrax on the wildebeest population and the l i f e history strategy of anthrax, I compare the anthrax wildebeest r e l a t i o n s h i p with the four models of host-pathogen re l a t i o n s h i p s . Examining the evolutionary consequences of the appropriate model, I assess the sign i f i c a n c e of anthrax to wildebeest and make recommendations on the management of the disease. Study -...Area More than half of A f r i c a south of the Sahara i s a savanna woodland commonly known as the miombo or bush (Ansell 1971). This i s the habitat of the tsetse f l y (Glossina spp.), the transmitter of trypanosomiasis. Because of t h i s i n f e c t i o n , domestic ungulate husbandry i s extremely d i f f i c u l t and human settlements are plagued with sleeping sickness. In addition, the a g r i c u l t u r a l value of t h i s habitat i s at best marginal. As a r e s u l t of these circumstances, the savanna woodland region of Afr i c a i s not suited to human settlement. The f a i l u r e of the ground-nut schemes i n Tanzania demonstrates t h i s (Matzke 1975). Because of t h i s lack of human settlement, t h i s region contains, today, almost a l l of the continent's wild animal populations i n what amounts to t h e i r o r i g i n a l abundance i n a lar g e l y untouched state. The southeastern segment of Tanzania i s almost completely miombo. In t h i s region, the few settlements that e x i s t are around i t s periphery (Bond i n prep.). The Selous Game Reserve, the largest wild animal sanctuary i n the world (55,000 sq km) i s situated i n the approximate center of t h i s region. 9 The Selous had s m a l l , s c a t t e r e d s e t t l e m e n t s p r i o r t o 1951. Besides t h e h e a l t h problems a s s o c i a t e d with i n s e c t s , s l e e p i n g sickness,, and an unpleasant c l i m a t e f o r much of the year, the people o f t e n s t a r v e d . Unable t o a d m i n i s t e r such a remote and i n a c c e s s i b l e r e g i o n , the area o f the Selous was g a z e t t e d as Game D i v i s i o n l a n d and human s e t t l e m e n t s were r e l o c a t e d . -The Miombo Research Center was e s t a b l i s h e d i n 1968 to d e a l with the management of Game D i v i s i o n l a n d s . The b a s i c n a t u r a l h i s t o r y of the r e g i o n i s d e a l t with by Rodgers (1969, i n p r e p . ) . The area i s midway between the T r o p i c of C a p r i c o r n and the eguator a t an approximate e l e v a t i o n of 100 m above sea l e v e l . R a i n f a l l i s r e s t r i c t e d almost e n t i r e l y t o a November to May wet season f o r an average of 760 mm per year (Rodgers and Ludanga 1973). C o n d i t i o n s are s e m i - a r i d . The r e s e a r c h c e n t e r i s adjacent t o the Lug»onya R i v e r , a seas o n a l t r i b u t a r y of the R u f i g i i R i v e r 80 km t o the n o r t h . L a t e i n the wet season the Lug'onya backs up and f l o o d s a l a r g e area i n the v i c i n i t y of the r e s e a r c h c e n t e r . T h i s r e g u l a r i n n u d a t i o n i s a s s o c i a t e d with the presence of t h r e e v e g e t a t i o n types i n a d d i t i o n t o the surrounding miombo ( F i g . 2 ) . F i r s t , t he r e g u l a r l y f l o o d e d c l a y s o i l s (black cotton) support a dense growth of t a l l , c o a r s e , f l o o d p l a i n g r a s s e s . Second, the p o o r l y drained, dark, sandy-clay s o i l a d j a c e n t to the f l o o d p l a i n supports s h o r t g r a s s e s and s c a t t e r e d j A c a c i a and Ter f f l i n a l i a spp.) thorn t r e e s . Adjacent t o e i t h e r of these two pr e v i o u s h a b i t a t s , w e l l d r a i n e d , grey, sandy s o i l s support medium l e n g t h g r a s s e s and a l i g h t , scrub woodland (Combretum and Ac a c i a spp. dominated).The w e l l d r a i n e d , red ( l a t e r i t e ) sandy 1 0 Figure 2. The d i s t r i b u t i o n of the habitat i n the region of the Hiombo Research Center 1971-1973 (1:250,000)-The Lug'onya River, i t s Lukuliro t r i b u t a r y , and the d i s t r i b u t i o n o f the floodplain are from Rodgers and Ludanga (1973)- The open, short grass region (stipling) i s the habitat i n which the population numbers of wildebeest were estimated. The well drained areas on the valley f l o o r support a l i g h t woodland, and the valley sides support the miombo. 12 s o i l s on the s i d e s o f the v a l l e y support the miombo; t a l l g r asses with a deciduous (Brachysteqia and J u l b e r n a r d i a spp. dominated) woodland ( F i g . 3) . T h i s d i v e r s i t y of h a b i t a t types was a p p a r e n t l y r e s p o n s i b l e f o r an e x c e p t i o n a l abundance of s e v e r a l w i l d animal s p e c i e s ; i n c l u d i n g (nomenclature a c c o r d i n g t o Meester and Setzer 1971) w i l d e b e e s t , impala (Aepyceros melampusj, zebra ( E g u u s b u r c h e l l i ) h a r t e b e e s t ( A l c e l a p u s lichensteini),„buffalo (Syncerus c a f f e r ) , elephant, e l a n d (Taurotragus oryx) a s a b l e (Hippotraqus_niger)., hippo (Hippopotamus amphibius)., warthog (Phacochoerus a e t h i o p i c u s ) , l i o n (Panthera l e o ) , l e o p a r d (Panthera pardus), s p o t t e d hyaena JCrgcuta c r o c u t a ) , and w i l d dog (Lycaon p i c t u s ) , and cheetah (Acinoayx l u b a t u s ) . 13 MATERIALS AND METHODS Reconnaissance An a e r i a l coverage of the e a s t e r n r e g i o n of t h e Selous was maintained throughout the study as pa r t o f the r o u t i n e census of the animal p o p u l a t i o n s . A ground coverage, mostly by v e h i c l e but o c c a s i o n a l l y by f o o t , was i n p a r t r e l a t e d t o r o u t i n e census and i n part r e l a t e d t o other game d i v i s o n d u t i e s . I t was obvious from our i n i t i a l r econnaissance and from e a r l i e r s t u d i e s (Rodgers 1 9 6 9 , S t o b a r t 1 9 7 0 ) t h a t there was a d i s c r e t e a g g r e g a t i o n of wildebeest a s s o c i a t e d with the Lug'onya f l o o d p l a i n . T h i s was a l s o the r e g i o n i n which the non-predatory m o r t a l i t y occurred so I have d e f i n e d t h i s a g g r e g a t i o n as the study p o p u l a t i o n . The d i s t r i b u t i o n of wildebeest i n the s h o r t g r a s s area adjacent t o the f l o o d p l a i n was mapped to s c a l e ( F i g . 2) on a drawing of the vegetation«s d i s t r i b u t i o n i n the area (Rodgers and Ludanga 1 9 7 3 ) . Outside of t h i s area I gained o n l y a g e n e r a l a p p r e c i a t i o n o f the wildebeest d i s t r i b u t i o n . The coverage of the study area was a l s o the source o f i n f o r m a t i o n on m o r t a l i t y , and predator abundance and d i s t r i b u t i o n . We recorded the l o c a t i o n and i n d i c a t i o n s o f pr e d a t i o n f o r c a r c a s s e s encountered on< the ground. On 15 of these c a r c a s s e s , d i a g n o s t i c t e s t s were performed (Appendix I ) . 14 G r o u n d T r a n s e c t s On t h e b a s i s o f t h e r e c o n n a i s s a n c e , t h r e e " v e h i c l e t r a c k s " r e p r e s e n t a t i v e o f t h e d i s t r i b u t i o n o f w i l d e b e e s t i n t h e s h o r t g r a s s r e g i o n s w e r e c h o s e n t o a c t a s t r a n s e c t s . Two o f t h e t h r e e r e g i o n s r e p r e s e n t e d b y t h e t r a n s e c t s ( L i h a n g w a a n d K a r i a k o o ) h a d t h e n o n - p r e d a t o r y m o r t a l i t y . T h e t h i r d a n d l a r g e s t r e g i o n ( H i w e n d e ) d i d n o t h a v e e v i d e n c e o f t h i s m o r t a l i t y . E a c h t r a n s e c t was d r i v e n a n a v e r a g e o f t h r e e t i m e s a m o n t h f o r 2 0 c o n s e c u t i v e m o n t h s . The v e h i c l e was a l o n g ^ w h e e l b a s e d , o p e n - ? b a c k e d l a n d r o v e r . T h e d r i v e r a n d r e c o r d e r r o d e i n t h e f r o n t a n d t w o t r a i n e d a s s i s t a n t s a n d I s t o o d i n t h e b a c k . S p e e d was a p p r o x i m a t e l y 3 0 k m / h -E a c h t i m e we o b s e r v e d a w i l d e b e e s t g r o u p , we r e c o r d e d t h e n u m b e r o f m a t u r e m a l e s , y e a r l i n g s , a n d c a l v e s , a n d t h e d i s t a n c e o f t h e g r o u p f r o m t h e t r a n s e c t s B i n o c u l a r s w e r e u s e d t o a s s i s t t h e c o u n t i n g . I f a g r o u p was n o t c l e a r l y o b s e r v e d , we l e f t t h e t r a n s e c t a n d d r o v e t o w a r d s i t . Age a n d s e x w e r e d i f f e r e n t i a t e d o n t h e f o l l o w i n g b a s i s { T a l b o t a n d T a l b o t 1 9 6 3 , S t o b a r t 1 9 7 0 ) . M a t u r e m a l e s ( t h r e e y e a r s o f a g e a n d o l d e r ) h a v e a l a r g e b o d y a n d h o r n s i z e , d a r k v e r t i c a l s t r i p e s o n t h e s h o u l d e r s , a n d a b o l d i n d e p e n d e n t m a n n e r . Y e a r l i n g s ( o n e t o t w o y e a r s o f a g e ) h a v e a d i s t i n c t i v e b o d y a n d h o r n s h a p e u n t i l t h e y a r e a p p r o x i m a t e l y 2 0 m o n t h s o f a g e . C a l v e s ( b i r t h t o o n e y e a r o f a g e ) h a v e a s m a l l o v e r a l l s i z e . E x c e p t i n a l l m a l e g r o u p s , m a l e s f r o m t w o t o t h r e e y e a r s o f a g e w e r e n o t d i f f e r e n t i a t e d f r o m m a t u r e f e m a l e s ( t w o y e a r s o f age a n d o l d e r ) d u r i n g t r a n s e c t o b s e r v a t i o n s . 15 The s h o r t c a l v i n g p e r i o d (based on f e t a l weights, 95% of the c a l v e s were conceived w i t h i n 15 days of A p r i l 11; Appendix II) f a c i l i t a t e d t h i s c a t e g o r i z a t i o n . A e r i a l Surveys Every s i x weeks f o r approximately one year, we s y s t e m a t i c a l l y surveyed the wildebeest p o p u l a t i o n i n the s h o r t g r a s s r e g i o n s adjacent to the f l o o d p l a i n . The a i r c r a f t (Cessna 207, Cessna 182, or a Piper 140) was flown a t an a l t i t u d e of 200 m above the ground a t a speed of 80 knots. Using two o b s e r v e r s , the survey took approximately t h r e e hours. We only attempted to count wildebeest i n groups of f i v e or more. The s i z e of l a r g e herds was estimated by counting i n approximated u n i t s of 10 animals. Shot sample We shot approximately f i v e wildebeest a month, f o r 30 c o n s e c u t i v e months. The r i f l e m e n d i s t i n g u i s h e d the age and sex c a t e g o r i e s d e s c r i b e d f o r t r a n s e c t o b s e r v a t i o n s . Females were examined f o r the presence or absence of a f e t u s , o r u t e r i n e or mammary gland i n d i c a t i o n s of a r e c e n t pregnancy (Appendix I I ) . In a d d i t i o n , we measured the weight of f e t u s e s t o determine time of c o n c e p t i o n (Appendix I I ) , and preserved o v a r i e s i n 10% f o r m a l i n f o r f u r t h e r i n f o r m a t i o n on pregnancy r a t e s (Appendix I I I ) -1 6 we removed the teeth from several animals of both sexes f o r h i s t o l o g i c a l examination. Based on the number of incremental l i n e s i n the cementum, I developed methods for the determination of wildebeest age {appendix IV) that were applied to the rest of the shot sample. Picked-up S k u l l C o l l e c t i o n Shortly a f t e r the s t a r t of the dry season* the grass was burned. This scorched background was excellent f o r the l o c a t i o n of whitish s k u l l s . During the 1972 and 1973 dry seasons, we systematically collected a l l the s k u l l s located i n the transect regions. Each s k u l l was c l a s s i f i e d according to i t s l o c a t i o n * age, sex, and year of death. Age was based on measurements of the enamel height of the f i r s t and t h i r d molars (appendix IV). Sex was based on horn c h a r a c t e r i s t i c s (Talbot and Talbot 1963, Stobart 1970). The year of death of a s k u l l was based on an appraisal of i t s deterioration. Skulls of older animals s t a r t to crumble and f a l l apart a f t e r approximately three years i n t h i s and s i m i l a r environments (Spinage 1972)^Younger animal s k u l l s do not l a s t as long because carnivores and rodents consume t h e i r s o f t e r and more proteinaceous bones. Socio-ecological Organization Estes (1969, 1976) described the soc i o - e c o l o g i c a l organization of wildebeest- in d i f f e r e n t habitats, but not in t h i s study's habitat type. My knowledge of t h i s population's 17 s o c i o - e c o l o g i c a l o r g a n i z a t i o n comes mainly from t r a n s e c t o b s e r v a t i o n s of the age and sex composition of the d i f f e r e n t group types. A d d i t i o n a l i n f o r m a t i o n came from the age and sex i d e n t i f i c a t i o n of tbe shot sample and picked-up s k u l l c o l l e c t i o n . From these c h a r a c t e r i s t i c s of the short g r a s s p o p u l a t i o n , I have drawn some i n f e r e n c e s about t h i s p o p u l a t i o n ' s s o c i o - e c o l o g i c a l o r g a n i z a t i o n . P o p u l a t i o n S i z e Ground t r a n s e c t s and a e r i a l s urveys were used to e s t i m a t e p o p u l a t i o n s i z e . Ground t r a n s e c t s provide a known area i n which a sample of the p o p u l a t i o n i s observed. T h i s area i s e s t i m a t e d from the s i g h t i n g d i s t a n c e s (Appendix V ) . I c o n s i d e r e d the t r a n s e c t as r e p r e s e n t a t i v e of the s h o r t g r a s s r e g i o n i t sampled. The number of wildebeest i n the r e g i o n r e p r e s e n t e d by a t r a n s e c t was obtained by a simple m u l t i p l i c a t i o n . The r e s u l t of each t r a n s e c t e s t i m a t i o n of wildebeest numbers andi the c o n f i d e n c e l i m i t s (Appendix V) were graphed f o r the p e r i o d o f the study. The "area-under" the 1972 p o r t i o n o f these graphs was measured using 5 mm g r i d d e d paper and d i v i d e d by 366 t o g i v e a mean d e n s i t y throughout the year. T h i s d e n s i t y I c o n s i d e r e d as a r e l a t i v e measure of the degree of occupation o f the three t r a n s e c t r e g i o n s . I e s t i m a t e d the number of wildebeest i n the s h o r t g r a s s r e g i o n s by combining the e s t i m a t e s a t 50 day i n t e r v a l s f o r the t h r e e t r a n s e c t s concerned. 18 The d i s t r i b u t i o n of the t o t a l population r e l a t i v e to the population i n the short grass regions was determined from the reconnaissance of the region and from an appreciation of the population's socio-ecological organization. Based on t h i s r e l a t i o n s h i p , I used the population size i n the short grass regions during the wet season, as determined from the transects, to estimate the o v e r a l l population s i z e . A e r i a l estimates of the short grass population were made by adding a proportion to account for wildebeest in groups of f i v e or l e s s . The proportion of the population i n groups of f i v e or le s s was determined from that month's ground transects. From the wet season r e s u l t s , I estimated the o v e r a l l population s i z e by adding an amount to account f o r the proportion of the o v e r a l l population outside of the short grass region., L i f e Table Age and sex d i s t r i b u t i o n s were based on pregnancy rates, the transect data, the shot sample, and the s k u l l c o l l e c t i o n r e s u l t s i n conjunction with my knowledge of the population's socio-e c o l o g i c a l organization. The c a l f proportion was calculated by applying the yearling and mature pregnancy rates (0.556 and 0.984. respectively; Appendix II) to the two-year ol d , and older than two-year old, female proportions. The mean c a l f and yearling proportions i n the transect data were used to approximate yearling and two year old proportions. The remaining proportion of the transect population was used to approximate the proportion three years of age and older. 1 9 The mature male and female age d i s t r i b u t i o n s sere e s t i m a t e d from the combination of the shot sample and picked-up s k u l l c o l l e c t i o n v a l u e s . The picked-up s k u l l c o l l e c t i o n was a p p a r e n t l y as r e p r e s e n t a t i v e of the p o p u l a t i o n as the c o l l e c t i o n of animals shot over a p e r i o d of t h r e e years. That i s , the number k i l l e d e i t h e r by human or n a t u r a l means, depended on the number a v a i l a b l e i n t h e c o h o r t . The male t o female p r o p o r t i o n s o f the three year and o l d e r age c l a s s e s were not based on t h e i r p r o p o r t i o n s i n the t r a n s e c t o b s e r v a t i o n s , i n the shot sample, or i n the: picked-up s k u l l c o l l e c t i o n because the s o c i o - e c o l o g i c a l o r g a n i z a t i o n excluded some age and sex c l a s s e s from the s h o r t g r a s s r e g i o n s sore than o t h e r s . An e s t i m a t e of these p r o p o r t i o n s was made on the b a s i s o f the r a t e s o f d e c l i n e with age of the male p r o p o r t i o n s r e l a t i v e to the female p r o p o r t i o n s i n the shot sample and picked-up s k u l l c o l l e c t i o n . The male and female p r o p o r t i o n s of the two-year o l d and younger age c l a s s e s were c o n s i d e r e d to be e g u a l , because of an equal f e t a l r a t i o (Appendix II) and because both sexes were i n mixed herds u n t i l over two years of age. A l i f e t a b l e c o n s t r u c t e d i n the above manner assumes a s t a t i o n a r y p o p u l a t i o n s i z e . P a t t e r n o f M o r t a l i t y I estimated the l e v e l of m o r t a l i t y i n two ways. The f i r s t was t o c a l c u l a t e the age s p e c i f i c r a t e s of m o r t a l i t y from the l i f e t a b l e . From these r e s u l t s , I d e r i v e d an o v e r a l l m o r t a l i t y r a t e . 20 The second method estimated the amount of m o r t a l i t y from known causes o f m o r t a l i t y . I assessed the causes of the non-r predatory m o r t a l i t y from examinations of c a r c a s s e s found d u r i n g our reconnaissance of the area, and from examinations o f the shot sample. The estimate o f the numbers of the d i f f e r e n t predator s p e c i e s was based on a f a m i l i a r i t y with the area., As the t r a n s e c t r e g i o n s were d i s c r e t e , I used the r e s u l t s of the picked-up s k u l l c o l l e c t i o n to es t i m a t e the t o t a l numbers o f s k u l l s produced each year i n each area. An es t i m a t e of the non-predatory m o r t a l i t y was the d i f f e r e n c e i n the number of s k u l l s between t h e areas with, and without, the m o r t a l i t y . I e s t i m a t e d the l e v e l of predator m o r t a l i t y from the r e s u l t s of other s t u d i e s of s i m i l a r p r e d a t o r s p e c i e s . . 21 RESULTS Reconnaissance The r e g i o n of the Lug'onya f l o o d p l a i n has a s e a s o n a l movement of wildebeest, During the wet season, almost a l l o f the p o p u l a t i o n c o n c e n t r a t e s i n the s h o r t g r a s s r e g i o n s a d j a c e n t to the f l o o d p l a i n , and d u r i n g the dry season, almost a l l o f the p o p u l a t i o n d i s p e r s e s i n t o the miombo. These movements are appa r e n t l y i n response to the a v a i l a b i l i t y of s h o r t green g r a s s , the p r e f e r r e d w i l d e b e e s t f o r a g e (Talbot and Talbot 1963)- Both h a b i t a t s have water s u p p l i e s throughout the year, but durin g the wet season, the open h a b i t a t a d j a c e n t to the f l o o d p l a i n produces an abundance of sh o r t g r a s s , while the miombo produces an abundance of t a l l c o a r s e g r a s s ; a v e g e t a t i o n w i l d e b e e s t avoid ( T a l b o t and T a l b o t 1963) . In c o n t r a s t , the open h a b i t a t produced very l i t t l e s h o r t g r a s s d u r i n g the dry season while the miombo produced a great d e a l . T h i s i s a consequence of the management's p o l i c y of burning the g r a s s e a r l y i n the dry season. The subsequent f l u s h of new growth i s q u i t e s u b s t a n t i a l i n the miombo and l a s t s f o r the r e s t of the dry season under shade t r e e s along the upper v a l l e y reaches (Hutch 1973)., The h a b i t a t v a r i e d among the th r e e s h o r t grass r e g i o n s r e p r e s e n t e d by t r a n s e c t s . The two with the non-predatory m o r t a l i t y had s e v e r a l shallow, s u r f a c e - c o l l e c t i o n type water s u p p l i e s ( F i g . 4) and g e n e r a l l y poor range c o n d i t i o n s . That i s . 22 water s u p p l i e s were warm, a l k a l i n e , and murky; and the range had major areas of exposed s o i l with a r e l a t i v e abundance of f o r b s and a s p a r c i t y of g r a s s . The one, l a r g e s t r e g i o n without the non-predatory m o r t a l i t y had s e v e r a l water s u p p l i e s fed by underground seepages (Rodgers 1969), and g e n e r a l l y good range c o n d i t i o n s . That i s , the water s u p p l i e s were r e l a t i v e l y c o o l and c l e a r with approximately a n e u t r a l pH, and the range had an abundant growth of s h o r t g r a s s . Age and Sex Composition T r a n s e c t o b s e r v a t i o n s : Mature males averaged 168 of the p o p u l a t i o n . Some were present as s o l i t a r y animals (3.9%), some were i n groups (bachelor herds) composed almost e n t i r e l y o f mature males (6.6%), and some were i n groups (mixed herds) composed o f a mixture of a l l age and sex c l a s s e s (5.5%) . Although twot-year o l d males were f r e g u e n t l y n o t i c e d i n bac h e l o r herds {approximately 1 t o 2%), they were not d i s t i n g u i s h a b l e from mature females i n the mixed herds. T h i s u n d i f f e r e n t i a t e d two-year o l d male and mature female c a t e g o r y averaged 41% (Table 1). Y e a r l i n g s and c a l v e s were present almost e n t i r e l y i n mixed herds, although one or t w o - y e a r l i n g s were o c c a s i o n a l l y n o t i c e d i n b a c h e l o r herds. T h e i r t r a n s e c t p r o p o r t i o n s averaged 18.5% f o r y e a r l i n g s and 25% f o r c a l v e s (Table 1). During both y e a r s , n o t i c e a b l e changes i n the p r o p o r t i o n s o f c a l v e s , y e a r l i n g s , mature males and the u n d i f f e r e n t i a t i e d category occurred a t the time o f the r u t ( F i g - 5 ) . No d i f f e r e n c e s were apparent between t r a n s e c t s , o r between the T a b l e . 1. The p r o p o r t i o n s o f the age and sex c a t e g o r i e s i n the t r a n s e c t p o p u l a t i o n . 1971 1972 1973 : _ — _ — . : Mean Month 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 15 7 11 11 18 24 18 18 19 24 17 11 11 9 13 18 18 17 19 16.0 50 44 52 42 32 34 32 50 50 51 38 31 38 33 41.0 15 17 9 13 18 24 26 18 18 15 19 22 21 23 18.5 21 28 27 27 27 25 24 25 25 22 24 27 21 21 24 21 25 29 26 25 25.0 Mature male U n d i f f e r e n t i a t e d Y e a r l i ng C a l f 2k F i g u r e 5. The t r e n d s i n the p r o p o r t i o n s of the c a l f , y e a r l i n g , mature male and u n d i f f e r e n t i a t e d c a t e g o r i e s i n the t r a n s e c t p o p u l a t i o n of Selous wildebeest, 1971-1973. A pronounced s h i f t i n these p r o p o r t i o n s occurs at the time of the r u t . The months a r e numbered 1-12, January to December. .6-O o • U N D I F F E R E N T I A T E D • - - C A L F a - — — Y E A R L I N G x - - M A L E o o Q -o ct: QL __ _ x _ - x _ — — J R U T - M O N T H 11 Vn 26 areas with and without the non-predatory m o r t a l i t y . Shot sample; The age and sex composition i s given i n Table 2. The r a t e of d e c l i n e with age of the three year and o l d e r age c l a s s e s was r e l a t i v e l y even, and approximately the same, f o r both sexes. The mature males taken were s o l i t a r y , or i n mixed herds, and mature females were o n l y from mixed herds. Two year o l d males were not i n t e n t i o n a l l y c o l l e c t e d , only when they were mistaken f o r mature females i n mixed herds. , Picked-up s k u l l c o l l e c t i o n ; He c o l l e c t e d a t o t a l of 1,269 s k u l l s from the three s h o r t g r a s s r e g i o n s , 94% o f which were from the area with the non-predatory m o r t a l i t y . The d i f f e r e n t i a t i o n of the sex of the s k u l l s showed that i n the r e g i o n without the non-predatory m o r t a l i t y , male m o r t a l i t y was f o u r times h i g h e r than i n the r e g i o n with the m o r t a l i t y (Table 3) and e i g h t times i t s corresponding p r o p o r t i o n i n the t r a n s e c t p o p u l a t i o n . Mature males were a p p a r e n t l y more s u s c e p t i b l e to predatory m o r t a l i t y than to the non-predatory m o r t a l i t y . The age and sex d i s t r i b u t i o n of the two-year and o l d e r s k u l l s (Table 4) was e s s e n t i a l l y the same as f o r the shot sample. Even the number of two-year o l d males i s much l e s s than the number of two-year o l d females. Data f o r the combined val u e s and percentage p r o p o r t i o n s of animals three years and o l d e r , a r e given i n Table 5. C o n d i t i o n s f o r c o l l e c t i o n of the s k u l l s were approximately the same i n the t h r e e areas. Based on my f a m i l i a r i t y with the e f f o r t and Caughley's (1977) f i n d i n g s t h a t complete coverages o f t e n overlook as much as they l o c a t e , I e s t i m a t e t h a t we l o c a t e d 50% o f the s k u l l s t h a t were present i n t h e s h o r t g r a s s 2 7 Table 2. The age and sex of 165 wildebeest shot between 1971 and 1973 i n the Selous Game Reserve. a g e Female Hale 2 3 4 5 6 7 8 9 10 11 12 20 19 10 7 i,- 9 6 3 3 1 0 0 6 28 11 12 8 9 9 2 2 0 0 13 0 0 Total 78 87 28 Table 3. The sex of picked-up wildebeest s k u l l s i n the regions with the non-predatory mortality and i n the region without t h i s mortality near the Miombo, Research Center, 1971-1973. Hale Female Sex Ratio Mortality 343 477 1: 1.4 Ho Mortality 49 17 1:0.35 29 Table 4. The age and sex of the picked-up s k u l l s Age 1 2 3 .4 5 6 7 8 9 1 0 1 1 1 2 13 Total Female 81 143 131 92 64 40 32 20 11 18 7 2 2 643 Male 42 53 133 92 78 60 47 30 17 11 3 4 0 570 Unknown 1 2 1 4 1 0 9 3 3 0 0 4 0 1 0 0 58 Total 135 210 274 193 145 103 79 50 32 29 11 6 2 1269 30 T a b l e 5 . The age a n d s e x o f t h e s h o t s a m p l e a n d p i c k e d - u p s k u l l s c o m b i n e d , and t h e p e r c e n t a g e p r o p o r t i o n s o f t h e t h r e e y e a r a n d o l d e r a g e c l a s s e s . Age F e m a l e M a l e 2 163 59 3 150 161 4 102 103 5 71 90 6 49 6.8 7 38 56 8 23 39 9 14 19 10 19 13 •.•11 7 3 12 2 •4 13 2 0 T o t a l 6 4 0 . 0 5 5 4 . 0 P e r c e n t F e m a l e 3 0 . 5 2 1 . 1 1 5 . . 9 . 1 0 . . 3 8 . 1 4 . , 8 3 . . 0 4 . . 0 1 . . 5 . . 4 . . 4 1 0 0 . 0 P e r c e n t M a l e 2 9 . 1 1 8 . 5 1 6 . . 2 1 2 . . 2 1 0 . 1 7. . 0 3 . , 4 2 . . 3 0 . . 5 0 . .7 0 . . 0 1 0 0 . 0 31 regions at the time of our c o l l e c t i o n s . The estimation of the year of death for 1,126 s k u l l s suggested l i t t l e change in mortality rate from 1970 to 1973 (Table 6) . A 50% e f f i c i e n t c o l l e c t i o n e f f o r t that supplied 282 of the current year s k u l l s could represent a t o t a l production of 564 s k u l l s of the type c o l l e c t e d . Socio-ecological Organization A t o t a l of 4,010 wildebeest groups were observed in the short grass regions. They were of three types: s o l i t a r y mature males, mixed herds, and bachelor herds. Their o v e r a l l proportions averaged 5.5:6.5:88.0. Noticeable changes i n the proportions occurred i n both years at the time of the rut (Fig. 6). The s o l i t a r y males behaved very much l i k e t e r r i t o r i a l males described by Estes (1969). The area of a t e r r i t o r y i n the Selous was approximately 0.5 sg km (the area of the short grass regions divided by the estimated number of t e r r i t o r i a l males) . Most of these t e r r i t o r i e s were maintained throughout the year. Estes (1969) recognized segregated bachelor herds composed of either yearlings, two-year old males, or mature males. The only bachelor herds recognized i n t h i s study were composed almost e n t i r e l y of mature males. The groups of mixed age and sex classes (mixed herds) were very large, an average of 48.8 animals compared to 28 animals in Serengeti (Watson 1967), 20 animals i n Kruger (Braack 1973), and 10 animals i n Ngorongoro*s sedentary-dispersed population (Estes 1969) . 32 Table 6- The estimated year of death of wildebeest s k u l l s i n the region with non-predatory mortality and i n the region without t h i s mortality. Year Ho Mortality Mortality Total 1970 13 24 1 254 1971 16 240 256 1972 30 313 343 i 1973 12 262 274 Total 71 1056 1127 Average number 17.8 264.0 282 per year 6.OS 94.OS 33 Figure 6. The trends i n the proportions of mixed herds, bachelor herds, and t e r r i t o r i a l males from January to November (both years combined) i n the transect population of the Selous wildebeest ,1972-1973- A pronounced s h i f t i n these proportions occurs at the time of the rut- The months are numbered 1-11, January to November. o O —i \ :b \ \ P o 1 o PROPORTION x o m 70 > O 70 x m ;o D I > P o >< m o r~ n 70 o to 35 The l a r g e s i z e of mixed herds i n the Selous was not a s s o c i a t e d with lowered c a l f s u r v i v o r s h i p - T h i s i s because the r e l a t i o n s h i p between a herd s i z e and c a l f p r o p o r t i o n showed almost no t r e n d ( F i g . 7), and because d u r i n g both years c a l f s u r v i v o r s h i p was e x c e p t i o n a l l y high (Table 1). Approximately 85% of the mixed herds moved i n t o the miombo d u r i n g the dry season. In t h i s h a b i t a t average numbers i n a herd decreased (Bodgers 1977). In the s h o r t g r a s s r e g i o n however, t h e r e were no n o t i c e a b l e t r e n d s i n the average s i z e of the mixed herds. Mixed herds were composed of an average of 26% c a l v e s , 21% y e a r l i n g s , 5% mature males, and 48% u n d i f f e r e n t i a t e d . There were no apparent d i f f e r e n c e s between t r a n s e c t s probably because of the m o b i l i t y and i n t e r a c t i o n s of mixed herds. Although two-year o l d males were not i d e n t i f i e d d u r i n g t r a n s e c t s , they were known t o be a p a r t of the u n d i f f e r e n t i a t e d category because two-year-old males were o f t e n mistakenly shot f o r mature females i n mixed herds. S e v e r a l o b s e r v a t i o n s i n d i c a t e t h a t two-year o l d males d i s a s s o c i a t e from mixed herds at about the time of the r u t . During both years, the p r o p o r t i o n of the u n d i f f e r e n t i a t e d component of mixed herds n o t i c e a b l y decreased and the other components i n c r e a s e d at t h i s time ( F i g . 8)., A decrease i n mixed herd s i z e was r e f l e c t e d i n a s l i g h t i n c r e a s e i n t e r r i t o r i a l male and b a c h e l o r herd p r o p o r t i o n s ( F i g . 6 ) . There i s a l s o evidence t h a t the two-year o l d males l e f t the t r a n s e c t p o p u l a t i o n when they l e f t the mixed herds. The o v e r a l l p o p u l a t i o n p r o p o r t i o n s o f the u n d i f f e r e n t i a t e d c a t e g o r y 36 F i g u r e 7. The r e l a t i o n s h i p between the s i z e o f a mixed herd and i t s c a l f p r o p o r t i o n i n the t r a n s e c t p o p u l a t i o n of Selous w i l d e b e e s t , 1971-1973. There i s a s l i g h t tendency f o r l a r g e r herds to have s m a l l e r c a l f p r o p o r t i o n s . o C A L F PROPORTION 0) I E m xi o 00 NI m + I + +4 + . + -JH-T + . 4 - 7 + + + T + ^ + ^ T x f ^ ++ + + +1 + + • +. +++ r 4 * + + + + + + .++ + + II d ro o O + • + 3 3 Figure 8. The trends in the mixed herd proportions of undifferentiated, c a l f , yearling, and mature male categories throughout the year, 1972-1973 (both years combined).. A marked s h i f t i n these proportions occurs at the time of the r u t . The months are numbered 1-11, January to November. 40 decreased and other categories increased at the time of the rut. Apparently these animals moved int o the scrub woodland or miombo, a behavior consistent with t h e i r underrepresentation i n the shot sample and picked-up s k u l l s c o l l e c t i o n s . In e f f e c t , the socio-ecological organization of the population excluded approximately 9% (the estimated two-year old male proportion), from the short grass regions f o r most of the wet season and the entire dry season. Population Size The area of the three transect regions and the length of the transects were, respectively, 55.1 sq km and 35.4 km f o r Lihangwa, 78.1 sq km and 26.5 km for Kariakop, and 174.2 sq km and 40.2 km f o r Hiwende (the one region without the non-predatory mortality). The graphs of the population estimate for each transect and the 95% confidence l i m i t s r e f l e c t e d the seasonal movements of the population. The o v e r a l l density estimates for 1972 from these graphs of wildebeest per sq km are 14.1 for Lihangwa, 20.6 f o r Kariakoo and 14-5 f o r Mi wen de. The summed estimates at 50 day i n t e r v a l s are graphed i n Figure 9. As the population appeared to concentrate i n the short grass region f o r an entire wet season, and as the population's reproductive strategy r e l i e d on spending the wet season i n the i short grass habitat (Appendix I I ) , the wet season's estimates i were averaged f o r an estimate of the number of wildebeest i n the short grass habitat at t h i s time of year. The r e s u l t s were 6,500 i n 1972 and 7,600 i n 1973., 41 These estimates indicated a 17$ increase, but the 95% confidence l i m i t s from each estimate averaged 27%. Therefore, a two-year average of 7,050 i s considered preferable to two separate estimates. The estimate of the o v e r a l l number of wildebeest reguires an addition> of 10% to the wet season transect estimates to account fo r the proportion that the population's socio-ecological organization excluded from the short grass region. That i s , the ov e r a l l number of wildebeest associated with the Lug'onya flo o d p l a i n was c i r c a 8,000. The number of animals seen during a e r i a l surveys* plus a proportion to account for animals i n groups of f i v e or l e s s i s graphed i n Figure 9. Like transect estimates, they r e f l e c t e d the seasonal movements, but the wet season estimates es p e c i a l l y were considerably l e s s than the transect estimates. . The average a e r i a l estimate during the 1973 wet season was 4,050 animals, 53% of the ground estimate. Considering how much a e r i a l estimates underestimate known population sizes (Caughley 1977), t h i s i s not a surprising discrepancy. L i f e Table The yearling proportion (the average c a l f proportion of the population) was 25%, the two-year old proportion (average yearling proportion) was 18.5%, and the older animal proportion was 56.5% (Table 1). 42 F i g u r e 9. The t r e n d s i n the estimated number of wildebeest i n the s h o r t grass r e g i o n s near the Miombo Research Center, 1971-1973, as determined from ground t r a n s e c t s and a e r i a l surveys.; A e r i a l e s t i m a t e s are c o n s i s t e n t l y l e s s than ground e s t i m a t e s . Day 1 i s December 13 # 1971 and Day 606 i s August 19, 1973-10-0 W E T I S E A S O N o - G R O U N D - A I R W E T I S E A S O N ol 13-12-71 D A T E 19 -8 -73 44 As the r e l a t i v e age d i s t r i b u t i o n of the three year and o l d e r animals i n the combined shot sample and p i c k e d up s k u l l c o l l e c t i o n (Table 5) was e s s e n t i a l l y the same f o r both sexes, I surmised t h a t t h e i r p r o p o r t i o n s of the p o p u l a t i o n would be the same. The sex r a t i o s f o r other t o t a l l y observed w i l d e b e e s t p o p u l a t i o n s a r e very c l o s e to 1:1 (Talbot and T a l b o t 1963, Watson 1967, E s t e s 1969). T h e r e f o r e , the o l d e r male and female p r o p o r t i o n s of the l i f e t a b l e are c o n s i d e r e d to be 28% and 28.5% r e s p e c t i v e l y . The c a l c u l a t e d c a l f p r o p o r t i o n from these p r o p o r t i o n s i s 33%. S c a l i n g the p r o p o r t i o n based on the a d d i t i o n of 33% c a l v e s to the p o p u l a t i o n , the percentages of the c a l f , y e a r l i n g , two-year o l d , o l d e r male and o l d e r female p r o p o r t i o n s are c l o s e to what they were o r i g i n a l l y observed t o be; that i s , 25%, 19%, 14%, 21%, and 21% r e s p e c t i v e l y . In other words, the l i f e t a b l e r e p r e s e n t s a f a i r l y s t a b l e age and sex c o n f i g u r a t i o n as w e l l as having a b u i l t i n s t a t i o n a r y p o p u l a t i o n s i z e . T h i s l i f e t a b l e , with the age d i s t r i b u t i o n o f the combined shot sample and picked-up s k u l l c o l l e c t i o n f o r the t h r e e year and o l d e r p r o p o r t i o n s (Table 5 ) , i s given i n F i g u r e 10. M o r t a l i t y P r e d a t i o n ; I estimated t h a t the predators of the wildebeest p o p u l a t i o n were 50 wild dogs, 20 hyaenas, 100 l e o p a r d s , 50 I l i o n s , and 2 cheetah. Not knowing t h e i r prey p r e f e r e n c e s , i t i s not p o s s i b l e to estimate the p r e c i s e number of wildebeest they r e q u i r e d . 45 F i g u r e 10- The trend i n the age c l a s s percentages i n the l i f e t a b l e o f the Selous w i l d e b e e s t , 1970-1973- I t i s g u i t e uniform f o r a l l age and sex c l a s s e s * i 47 P r e d a t o r m o r t a l i t y i n the S e r e n g e t i was estimated t o be 1Q% of the wildebeest p o p u l a t i o n , which was c o n s i d e r e d low because of the l a r g e s i z e of the area's prey p o p u l a t i o n s (Kruuk . and Turner 1967). C o n s i d e r i n g the r e l a t i v e l y modest s i z e of the prey p o p u l a t i o n s i n the Selous, I would expect the pr e d a t o r m o r t a l i t y t o be 15% at l e a s t . C o n s i d e r i n g a l s o the r e l a t i v e l y minor s i z e of the other prey p o p u l a t i o n s of s m a l l e r ungulates such as impala ( c i r c a 6,000; Gainer unpubl.) and g a z e l l e s G a z e l l a spp., the r e i s a p o t e n t i a l f o r a much g r e a t e r p r e d a t i o n of wildebeest c a l v e s i n the Selous. Humans ( r e s e a r c h , trophy hunters, and poachers) shot 80 or 1.5% of the y e a r l i n g and o l d e r animals each year. Based on the f o r e g o i n g , I es t i m a t e t h a t the p r e d a t o r requirements were probably a t l e a s t 15% of the y e a r l i n g s and o l d e r w i l d e b e e s t , and 25% o f the c a l v e s . . Disease: Only 3 (6%) of 50 f r e s h , unpredated c a r c a s s e s were c a l v e s . As c a l v e s were 25% of the p o p u l a t i o n , they were 5.4X l e s s a f f e c t e d by the non^predatory m o r t a l i t y t h a n o l d e r a n i m a l s . A l l o f the 15 f r e s h c a r c a s s e s t h a t were J d i a g n o s t i c a l l y i n v e s t i g a t e d had a t l e a s t minor i n d i c a t i o n s of an anthrax i n f e c t i o n . From f o u r of the f i v e attempts that u t i l i z e d mice to a s s i s t the i s o l a t i o n of pathogenic organism. B a c i l l u s a n t h r a c i s was r e c o v e r e d . There were no i n d i c a t i o n s of other pathogenic organisms (Appendix I ) . The survey of p a r a s i t e s and d i s e a s e s i n the shot sample d i d not d i s c l o s e any s i g n i f i c a n t p a t h o l o g i c a l l e s i o n s * T h i s i s to be expected as animals weakened by a pathogen would be prone to p r e d a t i o n . The agent t h a t caused the non-predatory m o r t a l i t y i n 48 t h i s study a p p a r e n t l y produced a sudden death o f the host. The h i g h l y c h a r a c t e r i s t i c e p i z o o t i o l o g i c a l f e a t u r e s of anthrax a r e t h a t i t p e r i o d i c a l l y causes sudden deaths i n a l a r g e p r o p o r t i o n of a p o p u l a t i o n of g r a z i n g ungulates i n areas such as where the non-predatory m o r t a l i t y occurred i n t h i s study; and young o f the year a r e a f f e c t e d l e s s than o l d e r animals (Minett 1952, Choquette 1970, Ebedes 1975) . The only d i f f e r e n c e i n sources of m o r t a l i t y between the areas with and without the non-predatory m o r t a l i t y was anthrax. As the lower d e n s i t y of w i l d e b e e s t i n the a r e a without the m o r t a l i t y was more than compensated f o r by a much g r e a t e r c o l l e c t i o n area than i n the combined area with the m o r t a l i t y , the number o f s k u l l s i n the area with the non-predatory m o r t a l i t y , i n excess of the number of s k u l l s i n t h e area without the m o r t a l i t y , i s probably a good r e p r e s e n t a t i o n of the anthrax m o r t a l i t y . I t was estimated t h a t t h e r e was 564 s k u l l s of the type i n the picked-up s k u l l c o l l e c t i o n produced i n the s h o r t g r a s s area each year. The s k u l l s of y e a r l i n g s are more r a p i d l y removed from the environment than the s k u l l s of o l d e r animals, so t h e i r p r o p o r t i o n of the c o l l e c t i o n (10%) i s deducted f o r e s t i m a t i o n s of the m o r t a l i t y r a t e s . That i s , 512 s k u l l s of two-year o l d and o l d e r w i l debeest were produced, 88% (Table 6) of which (451) were the r e s u l t of the non-predatory m o r t a l i t y . T h i s r e p r e s e n t s a m o r t a l i t y r a t e of 10% of t h i s segment of the p o p u l a t i o n . As the m o r t a l i t y r a t e from c a r c a s s examinations was the same f o r y e a r l i n g s , but only a q u a r t e r as much f o r c a l v e s , i t was estimated t h a t 1 0 % of the y e a r l i n g s and o l d e r animals and 3% of 4 9 the calves were k i l l e d by anthrax each year (9% of t h e o v e r a l l population) . , Level.of mortality; The estimation of mortality from known sources was approximately 25% f o r calves and 25% for older animals. Mortality from unrecognized sources was perhaps another 10%. These are high estimates considering the more or l e s s constant mortality rate of 25% indicated i n the l i f e table (Fig. 11). However, there was evidence that the predatory and disease mortality was not s t r i c t l y additive. Very few of the carcasses encountered i n the f i e l d had in d i c a t i o n s of predation, and several times we suspected predators of scavenging anthrax carcasses., In one instance, a s o l i t a r y mature male l i o n was associated with a carcass from which a blood smear was made. The blood smear contained morphological features that were highly c h a r a c t e r i s t i c of B. anthracis. i 50 F i g u r e 11. The t r e n d i n the m o r t a l i t y r a t e s d e r i v e d from t h e l i f e t a b l e of the S e l o u s w i l d e b e e s t , 1970-1973.,It i s r e l a t i v e l y c onstant throughout the p o p u l a t i o n ' s age span. 3 ivy Ainviuow o 52 DISCUSSION P o p u l a t i o n C h a r a c t e r i s t i c s There were two unusual f e a t u r e s of the Selous p o p u l a t i o n . One was i t s s o c i o - e c o l o g i c a l o r g a n i z a t i o n and the other i t s l i f e t a b l e . , The herd s t r u c t u r e was s i m i l a r t o both s o c i o - e c o l o g i c a l o r g a n i z a t i o n s d e s c r i b e d f o r wildebeest by E s t e s (1969, 1976). P a r t of the p o p u l a t i o n was l i k e the s e d e n t a r y - d i s p e r s e d p o p u l a t i o n i n Ngorongoro; t h a t i s , t e r r i t o r i a l males and cow-c a l f herds r e s i d e d i n an open s h o r t g r a s s r e g i o n throughout the year. But most of the p o p u l a t i o n was l i k e the mobile-aggregation p o p u l a t i o n i n Ngorongoro, That i s , the herds moved to the h a b i t a t with the best supply of s h o r t g r a s s . However, the composition of the Selous herds was a l s o i n c o n s i s t e n t with both of E s t e * s p o p u l a t i o n s . I t d i d not have the s t r i c t s e g r e g a t i o n between s m a l l cow-calf u n i t s and non-breeding animals of E s t e § s s e d e n t a r y - d i s p e r s e d o r g a n i z a t i o n . I n s t e a d , i t had l a r g e mixed herds t h a t c o n t a i n e d y e a r l i n g , and t o some extent, two-year o l d males. But t h i s was not the complete absence of s e g r e g a t i o n t h a t C h a r a c t e r i z e d Este's mobile ag g r e g a t i o n s . Mature males e s t a b l i s h e d t e r r i t o r i e s o r formed bachelor herds, and two-year o l d males were o u t s i d e the mixed herds f o r most of the year. 53 In general, the Selous socio-ecological organization was a p a r t i a l segregation of mobile-aggregates i n combination with permanently established t e r r i t o r i e s . This grouping i s not related to the presence of anthrax.; Bather, the water and short grass i n the open habitat during the wet season was probably the best source of nutrition-appropriate to good breeding success (Appendix I I ) . The permanent (although reduced) supply of these water and short grass supplies provided sustenance f o r t e r r i t o r i a l males and a few mixed herds throughout the year. The l i f e table had a strong representation of young animals. L i f e tables of other wildebeest populations have a major population component over the age of ten and estimate ages as high as 24 years (Watson 1967, Brack 1973, Andere 1976). In the Selous population, le s s than 5% of the animals were over the age of ten and the oldest age was estimated to be 14 years. The mortality curve from the l i f e table was e s s e n t i a l l y h o rizontal (Fig. 11). That i s , the mortality r a t e was the same regardless of age. The t y p i c a l ungulate mortality curve i s 0-shaped (Caughley 1977). There are two reasons f o r the unusual d i s t r i b u t i o n of the Selous age classes. The f i r s t i s that the age determination methods employed i n t h i s study predicted much younger ages than the methods used in other wildebeest studies. This would reduce the average age by approximately 20% i n the Amboseli population (Andere 1976), approximately 30% i n the Kruger population (Braack 1974), and approximately 40% i n the Serengeti population (Watson 1967). 54 The second reason i s r e l a t e d to the presence o f anthrax. Anthrax k i l l e d only 3% of the c a l v e s but 10% of the o l d e r animals. a l s o , c a r n i v o r e s t h a t otherwise preyed upon wildebeest c a l v e s probably scavenged anthrax c a r c a s s e s i n s t e a d . That i s , the d i s e a s e i n d i r e c t l y reduced c a l f m o r t a l i t y at the expense o f o l d e r animal m o r t a l i t y , as a consequence, c a l f s u r v i v o r s h i p , which i s low i n t y p i c a l ungulate p o p u l a t i o n s , was very high and very few o f the o l d e r animals s u r v i v e d t o experi e n c e the high m o r t a l i t y r a t e a s s o c i a t e d with o l d age..... The Selous age d i s t r i b u t i o n i s i n a sense, unproductive l a c k i n g a l a r g e p r o p o r t i o n s of the middle aged, r e p r o d u c t i v e l y capable animals ( C h i l d 1972). I n many r e s p e c t s , i t i s s i m i l a r t o a l i g h t l y harvested p o p u l a t i o n i n which the k i l l i s of e i t h e r sex. The p o p u l a t i o n i s not as p r o d u c t i v e of young animals as i t coul d be, but i s n e v e r t h e l e s s s u f f i c i e n t l y provided with r e c r u i t s t o be s t a b l e and p o t e n t i a l l y capable of a r a p i d i n c r e a s e i n abundance. In summary, the Selous wildebeest p o p u l a t i o n does not appear t o have s u f f e r e d any adverse consequences as a r e s u l t o f heavy l o s s e s t o anthrax. I n s t e a d , i t appears to have qained r e s i l i e n c e and s t a b i l i t y i n the sense of fl o i l i n g (1973).* C h a r a c t e r i s t i c s o f anthrax I t i s g e n e r a l l y c o nsidered t h a t the plague i n Egypt a t the time o f Moses was anthrax (Klema and Klemm 1959). With the extreme m o b i l i t y o f such t r a n s p o r t e r s o f the i n f e c t i o n as v u l t u r e s (aeqypidaeV (Ebedes 1975), anthrax has probably had a r e l a t i o n s h i p with w i l d e b e e s t from p r e h i s t o r i c t i m es. 55 Occurrence o f anthrax i n i n d i v i d u a l s ; Pasteur demonstrated t h a t "germs" were not spontaneously generated w i t h i n an animal by p r e s e n t i n g a h o s t - e x t e r n a l environment l i f e - c y c l e f o r anthrax organisms. B a c i l l u s a n t h r a c i s - When he spread b l o o d o f i n f e c t e d animals c o n t a i n i n g the v e g e t a t i v e forms pn s o i l , s pores formed. These spor e s were extremely r e s i s t a n t t o environmental c o n d i t i o n s . When Pasteur i n t r o d u c e d spores i n t o e x p e r i m e n t a l animals, the animals c o n t r a c t e d anthrax and t h e i r blood c o n t a i n e d v e g e t a t i v e forms of the organism. Subsequent work demonstrated t h a t the l e v e l of s e v e r i t y o f the d i s e a s e was dependent upon t h e dosage of organisms (Seto and Takizawa 1969, Schlingman e t a l * - 1956). Jin bovidae, the acute l e v e l of i n f e c t i o n r e q u i r e s an o r a l a d m i n i s t r a t i o n of spores (Hutyra e t a l 1938, Schlingman e t a l . 1956, L i n c o l n e t a l . 1964) . P a r e n t e r a l i n n o e u l a t i o n s , i n c l u d i n g t h o se of blood sucking i n s e c t s (Sens and Min e t t 1944), only cause low l e v e l i n f e c t i o n s . Animals with an acute i n f e c t i o n d i e r e l a t i v e l y s h o r t l y a f t e r the onset o f symptoms (HcConnel e t a l 1972) j sometimes as r a p i d l y as 30 minutes (Fox et a l 1977). T h i s i s a p p a r e n t l y because t h e r e i s a sudden r e l e a s e o f organisms and t o x i n s i n t o the c i r c u l a t i o n ( L i n c o l n e t a l 1964). Great numbers o f a n t h r a c i s i n the v e g e t a t i v e form a re present i n the c i r c u l a t i o n of an animal a t the time of i t s death. I f these organisms do not escape from the c a r c a s s t o the e n v i r o n m e n t , t h e p u t r i f i c a t i o n of the c a r c a s s e l i m i n a t e s them (Ste i n 1947, Toschkoff and Veljanov 1970) . I f e x t e r n a l c o n d i t i o n s f a v o r s p o r u l a t i o n o f the organisms, they w i l l be 5 6 resistant to v i r t u a l l y any environmental i n s u l t {Stein 1947). Although capable of surviving the most severe environmental conditions, spores germinate i n most s o i l s ; at a rate proportionate to the s o i l ' s b i o l o g i c a l a c t i v i t y (Hinett 1950, Zarubxinskii 1959). Germinated, B. anthracis are very quickly destroyed i n b i o l o g i c a l l y active s o i l s (Hinett and Dhanda 1941, Minett 1950, Zarubkinskii 1959). This explains why anthrax does not reoccur i n many areas i n which i t has been present. I t also explains why enormous quantities of spores have not accumulated i n environments that are supposedly incapable of eliminating them. Occurrence of anthrax i n populations; Anthrax usually occurs as an outbreak of acute i n f e c t i o n s . That i s , a high proportion of a population p e r i o d i c a l l y dies of the disease. In ce r t a i n areas, these outbreaks tend to recur during c e r t a i n c l i m a t i c conditions i n certain areas (Stein1948, Hinett 1952, Van Ness 1971, Ebedes 1975). Environmental aspects of outbreaks have several features i n common. The climate tends to be hot, dry and dusty. The habitat tends to be semi-arid grasslands with a l k a l i n e , surface-c o l l e c t i o n type water supplies, flange conditions are usually poor and large numbers of blood-sucking insects are often present. A. Prevailing theories: The close association of anthrax outbreaks with environmental conditions i s the basis of two explanations f o r the cause of outbreaks. The f i r s t theory recognizes that the spore germinates in the s o i l , and suggests that i n c e r t a i n areas, conditions favor the germination. 57 p r o l i f e r a t i o n and then subseguent s p o r u l a t i o n of anthrax organisms i n the environment. T h i s exposes the in d i g e n o u s animals t o h i g h dosages of spores which causes the acute i n f e c t i o n s (Van Ness 1.971). There a r e t h r e e i n c o n s i s t e n c i e s with t h i s theory. F i r s t , v e g e t a t i v e forms of B-. a n t h r a c i s a r e v i r t u a l l y i m p o s s i b l e to recover from b i o l o g i c a l l y a c t i v e s o i l s ( H i n e t t and Dhanda 1941, Minett 1950). Second, i f B. a n t h r a c i s i s c u l t u r e d on non-animal media, the organism r a p i d l y l o s e s i t s v i r u l e n c e ; hence the b a s i s of i t s v a c c i n e (Sterne 1939). And t h i r d , the environmental c o n d i t i o n s , a s s o c i a t e d with many outbreaks do not have a sequence t h a t would promote such a l i f e c y c l e (Hinett 1952, Ebedes 1975, Appendix I) . Another theory proposes t h a t outbreaks occur because i n c e r t a i n s i t e s d u r i n g c e r t a i n c o n d i t i o n s spores accumulate f a s t e r than the b i o l o g i c a l a c t i v i t y o f the environment d e s t r o y s them. When indigenous animals are exposed t o a l a r g e accumulation o f spores, they c o n t r a c t the acute i n f e c t i o n . The evidence f o r t h i s theory i s from South A f r i c a . At Kruger N a t i o n a l Park, the e x c e p t i o n a l l y f r e q u e n t occurrence o f anthrax i n Kudu (Traqelaphus s t r e p s i c e r o s ) was a s s o c i a t e d with the season during which t h e r e were hoards of blow f l i e s ( C a l l i p h o r a spp.) t r a n s p o r t i n g i n f e c t e d m a t e r i a l from anthrax c a r c a s s e s t o surrounding v e g e t a t i o n . During t h i s season, the contaminated v e g e t a t i o n was browsed by the Kudu (Vos 1973). At Kruger and Etosha N a t i o n a l Parks, anthrax outbreaks occurred i n g r a z i n g ungulates d u r i n g the season when l a r g e numbers o f v u l t u r e s t r a n s p o r t e d i n f e c t e d m a t e r i a l from c a r c a s s e s 58 to watering s i t e s where the ungulates were concentrating (Vos 1973, Ebedes 1975). Both of these studies reported that the concentration of anthrax spores was highest around the surface-c o l l e c t i o n type water supplies. A f a i l i n g of both prevailing theories i s that they do not consider the le s s than acute i n f e c t i o n s that an indigenous population i s most l i k e l y to contract. The retropharyngeal lymph nodes of slaughtered ungulates from anthrax areas often contain low l e v e l i n f e c t i o n s (Stein 1948, Provost and Tronette 1957). F i n a l l y , the above theories do not consider the natural immunity created by less than f a t a l i n f e c t i o n s . Serological surveys of animals from anthrax areas show a high proportion of s i g n i f i c a n t reactions to anthrax antigen (Provost et a l 1974, Ebedes 1975). Also, vaccination with a capsulated type vaccine causes few adverse reactions i n anthrax area animals but i t causes many i n non-anthrax area animals (Bruner and G i l l e s p i e 1966, Siegmund 1967, Gainer unpubl.). B. A more r e a l i s t i c hypothesis; The environmental conditions associated with anthrax outbreaks are known to reduce the resistance of i n d i v i d u a l s (Webster 1970, Hudson e t a l . 1974, Emslie 1977) and populations (Wilson and Hirst 1977) to i n f e c t i o n . If t h i s resistance i s lowered when animals are exposed to anthrax organisms, or i f they have a chronic i n f e c t i o n , then otherwise i n s i g n i f i c a n t i n f e c t i o n s can cause acute i n f e c t i o n s . That i s , an outbreak occurs because of changes in the host population rather than because of changes i n the anthrax population. Three otherwise puzzling a t t r i b u t e s of the disease are 59 e x p l a i n e d by t h i s h y p o t h e s i s . F i r s t , r e l a t i v e l y low numbers of spores need t o be a v a i l a b l e . In a c t u a l f a c t , sources of spores i n q u a n t i t i e s or c o n c e n t r a t i o n s s u f f i c i e n t t o cause acute i n f e c t i o n s a r e r a r e l y found i n anthrax areas (Appendix I ) - I f the low; l e v e l i n f e c t i o n i s c h r o n i c , then the source of i n f e c t i o n c o u l d even be someplace other than the anthrax area. Second, blood s u c k i n g i n s e c t s , o f t e n a s s o c i a t e d with outbreaks, can tr a n s m i t the i n f e c t i o n . And t h i r d , i f c h r o n i c i n f e c t i o n s a re an important source of acute i n f e c t i o n s , then a t the time of the outbreak, c a l v e s would have had a s m a l l e r ; chance of a c q u i r i n g the i n f e c t i o n . In a c t u a l f a c t , c a l v e s are r e l a t i v e l y l e s s a f f e c t e d by anthrax during outbreaks than o l d e r animals (Brunsdon 1968, Choguette e t a l . 1972, Ebedes 1975, Fox e t a l . 1977). In summary, anthrax outbreaks r e c u r i n some areas because t h e i r environment f a v o r s the p e r s i s t e n c e and t r a n s m i s s i o n of anthrax s p o r e s . In these areas, animals a r e commonly exposed to r e l a t i v e l y low dosages of spores t h a t are i n c o n s e q u e n t i a l to hea l t h y animals, and which may a c t u a l l y s t i m u l a t e a r e s i s t a n c e t o more severe i n f e c t i o n s from higher dosages of spores. But when environmental c o n d i t i o n s reduce the r e s i s t a n c e of a p o p u l a t i o n , outbreaks occur. Anthrax-wildebeest r e l a t i o n s h i p S a l i e n t i n f o r m a t i o n from the wildebeest study and the l i f e h i s t o r y s t r a t e g y of anthrax are compared t o the f o u r models o f the host-pathogen r e l a t i o n s h i p presented i n the i n t r o d u c t i o n i n order t o understand the e v o l u t i o n a r y o r u l t i m a t e consequences of 60 the r e l a t i o n s h i p . . The f i r s t model of an unbalanced r e l a t i o n s h i p , with a host r e s i s t a n t t o the pathogen's i n f e c t i o n , i s i n a p p r o p r i a t e p r i m a r i l y because wildebeest were f r e q u e n t l y i n f e c t e d with anthrax. The second model of an unbalanced r e l a t i o n s h i p , with the pathogen re d u c i n g the success of w i l d e b e e s t i s i n a p p r o p r i a t e f o r two main reasons. F i r s t , the e f f e c t o f anthrax on the wildebeest p o p u l a t i o n was not to reduce i t s numbers. I f anything, i t was b e n e f i c i a l t o i t s dynamics. Second, wildebeest i n g e n e r a l have had a l o n g time t o evolve a r e s i s t a n c e t o anthrax, I f anthrax was reducing the success of the w i l d e b e e s t s p e c i e s , w i l d e b e e s t would not be what i s a p p a r e n t l y the most s u s c e p t i b l e , n a t u r a l host s p e c i e s f o r t h i s i n f e c t i o n . The t h i r d model, of a balanced r e l a t i o n s h i p with the pathogen r e d u c i n g the c o n d i t i o n of i t s p r e d a t o r - f r e e host without r e d u c i n g the success of the host's s p e c i e s , i s i n a p p r o p r i a t e f o r two main reasons. In t h i s study, no weak animals were r e c o g n i z e d because they were predisposed to p r e d a t i o n * Second, th e l i f e h i s t o r y s t r a t e g y of anthrax i s such t h a t i t does not d e b i l i t a t e the animal t h a t i t i n f e c t s and predispose i t to p r e d a t i o n before i t k i l l s i t . The f o u r t h model o f a balanced r e l a t i o n s h i p , with the i n f e c t i o n of a predated host by a pathogen t h a t does not reduce the success of the host s p e c i e s , i s the most a p p r o p r i a t e model. Anthrax a p p a r e n t l y does not decrease the success of w i l d e b e e s t as evidenced from t h i s w i l d e b e e s t study and from the f a c t t h a t wildebeest have not evolved a r e s i s t a n c e to the d i s e a s e . A l s o , 6 1 the l i f e h i s t o r y s t r a t e g y of anthrax a v o i d s r e d u c i n g a ho.st*s c o n d i t i o n and p r e d i s p o s i n g i t t o p r e d a t i o n by c a u s i n g the sudden death of the host-Other f e a t u r e s of the d i s e a s e e x p l a i n s how anthrax may k i l l w i ldebeest without reducing the s u c c e s s o f the w i l d e b e e s t s p e c i e s - The occurrence of anthrax i n the Selous g r a z i n g s p e c i e s and with anthrax-area g r a z e r s i n g e n e r a l , i s a s s o c i a t e d with poor range c o n d i t i o n s . That i s , e n v i r o n m e n t a l l y s t r e s s e d animals. Environmental s t r e s s , such as poor range c o n d i t o n s , reduces an animal's a b i l i t y t o reproduce ( S a d l e i r 1969).Studies have i n f a c t shown t h a t the animals t h a t s u r v i v e p e r i o d s of r e s o u r c e shortages tend to be those with the h i g h e s t r e p r o d u c t i v e p o t e n t i a l (Harkgren 1969, C h i l d 1972, Appendix I I ) . I t i s reasonable to expect t h a t those w i l d e b e e s t t h a t s u f f e r e d a t the expense o f anthrax were those with low r e p r o d u c t i v e p o t e n t i a l . The removal of animals with low r e p r o d u c t i v e p o t e n t i a l conserves r e s o u r c e s f o r animals with h i g h e r r e p r o d u c t i v e p o t e n t i a l . Thus, i n these circumstances, the m o r t a l i t y a s s o c i a t e d with anthrax may a c t u a l l y improve the e v o l u t i o n a r y success o f the wildebeest s p e c i e s . The obvious s u s c e p t i b l i t y of wildebeest to t h i s d i sease suggests t h a t the s p e c i e s may a c t u a l l y have evolved a s u s c e p t i b i l i t y t o anthrax to take advantage o f the e v o l u t i o n a r y b e n e f i t s a s s o c i a t e d with the i n f e c t i o n ; a s t r a t e g y Sprent (1969) has proposed f o r balanced h o s t - p a r a s i t e r e l a t i o n s h i p s . 62 MANAGEMENT STRATEGY Population ecologists have long recognized the differences between the proximate and ultimate causes of mortality. Proximate causes of mortality are thought to reduce the magnitude of population f l u c t u a t i o n s that might otherwise cause extinction (McLaren 1971). There are i n d i c a t i o n s that anthrax served t h i s function with wildebeest. A large-scale die-off of wildebeest from starvation, a r e l a t i v e l y ultimate mortality f a c t o r , resulted i n an age d i s t r i b u t i o n that promoted further population f l u c t u a t i o n (Child 1972). In t h i s study, the death of substantial numbers of wildebeest from anthrax, a proximate mortality factor, i s not associated with a large reduction i n numbers, but i s associated with the production of a r e s i l i e n t and stable age d i s t r i b u t i o n . For t h i s reason, the control of the disease would not be an advantage to the population. This does not mean that anthrax i s not a disadvantage to a manager of an animal population. Actually, the reverse i s often true.; Anthrax threatens the existence of several populations of wildebeest and other ungulates a r t i f i c i a l l y manipulated f o r exhibition i n game parks and sanctuaries (Choquette 1970, Vos 1973, Ebedes 1975). Also, the occurrence of anthrax i n l i v e s t o c k populations sometimes causes an enormous reduction in t h e i r y i e l d . Hhen considering the control of anthrax, the advantages of manipulating the host population should be considered. With the Selous wildebeest f o r instance, a l i g h t harvest program may pay 63 f o r i t s e l f and at the same time reduce the occurrence of the d i s e a s e . When environmental c o n d i t i o n s d e t e r i o r a t e , a r e d u c t i o n i n the number o f animals reduces t h e i r occupation of poor range. T h i s , i n t u r n , would improve the range. By reducing the number of animals i n poor c o n d i t i o n , the number l o s t t o anthrax would be reduced. I f the h a r v e s t o f the Selous w i l d e b e e s t i s of o l d e r animals, the herd s t r u c t u r e would maintain a s t a b l e age c o n f i g u r a t i o n . The estimated m o r t a l i t y r a t e of anthrax was 10% of the o l d e r animals, or 600 y e a r l i n g and o l d e r animals, per year. A h a r v e s t r a t e a t t h i s l e v e l would cause a great r e d u c t i o n of anthrax l o s s e s with a minor r e d u c t i o n i n the population., As long as the p o p u l a t i o n s i z e i s above approximately h a l f of i t s unharvested, e g u i l i b r i u m s i z e , a r e d u c t i o n of the p o p u l a t i o n s w i l l p r obably cause an i n c r e a s e i n i t s p r o d u c t i v i t y (Caughley 1977). 6 4 LITERATURE CXTED Andere,D.K. 1975. The dynamics of pasture use by .wildebeest (and c a t t l e ) i n the Amboseli b a s i n . M. Sc., 0. of N a i r o b i . Anderson,R-C. 1971.. M e t a s t r o n g y l i d lungworms. I n : P a r a s i t i c Diseases o f Wild Mammals, ed by J.W.Davis and R.C.Anderson. Iowa S t a t e U n i v e r s i t y P r e s s , Ames. Anon. 1971. D i s t r i b u t i o n map of anthrax i n A f r i c a . 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Siegmund,O.H. 1967. The Merck V e t e r i n a r y Manual. Merck and Co., Rahway. S i n c l a i r , A . B . E . 1977- The A f r i c a n B u f f a l o - 0.,Of Chicago P r e s s , Chicago. Spinage,C.A. 1962. Rinderpest and f a u n a l d i s t r i b u t i o n p a t t e r n s . A f r i c a n W i l d l i f e 16:55-60. 1972. A f r i c a n l i f e t a b l e s . Ecology 53:645-652. Sprent,J.E.A. 1969. E v o l u t i o n a r y a s p e c t s of immunity i n z o o p a r a s i t i c i n f e c t i o n s , i n : Immunity to P a r a s i t i c Animals, ed by G.J.Jackson, R.Herman and I . S i n g e r . 1:3-62. S t e i n , C D . 1947. Some o b s e r v a t i o n s on the t e n a c i t y of anthrax. Vet. Med. 42:13-22. — — - r - — . 1948. Incidence of anthrax i n l i v e s t o c k with s p e c i a l r e f e r e n c e t o c o n t r o l measures i n the v a r i o u s s t a t e s . ,Vet^ Med. 43:463^469. Sterne,M. 1939. The use of anthrax v a c c i n e s prepared from a v i r u l e n t (uncapsulated) v a r i a n t s of B. a n t h r a c i s . Onderstepoort J . Vet. S c i . Anim. 13:307-312. Stobart,P.T. 1970. Ecology of the Nyasa w i l d e b e e s t , L i c h e n s t e i n h a r t e b e e s t and southern impala i n the e a s t e r n Selous.Tanzania Game D i v i s i o n mimeog., Dar-es-Salaam. TiaibotvL-M. and M-fl.Talbot. 1963. The wildebeest o f the western Masailand, East A f r i c a , Wildl,. Monog. 12. Toschkoff,A. and D.Veljanov. 1970. S p o r u l a t i o n and v i r u l e n c e o f B a c i l l u s a n t h r a c i s i n opened and unopened c a r c a s s e s . Arc h i v - Exper- Vet. 24:1153-1160. . Trainer,D.O. 1978- W i l d l i f e d i s e a s e -a p r o f e s s i o n ? J- W i l d l . Dis. 14:152-156. 69 Van Ness, G.B. 1971. Ecology of anthrax. Science 172:1303-1307. Vos,V. de. 1973. Black bane (anthrax) rampant i n our nature r e s e r v e s . Custos 2(12):5-9 and 2(13): 10-14. Watson, R.M. 1967. P o p u l a t i o n ecology of w i l d e b e e s t e i n the S e r e n g e t i (Connochaetes t a u r i n u s a l b o l u b a t u s Thomas) - Ph. D., Cambridge 0. Webster,A.J.F. 1970. Environmental and p h y s i o l o g i c a l i n t e r a c t i o n s i n f l u e n c i n g r e s i s t a n c e t o i n f e c t i o u s d i s e a s e , i n : R e s i s t a n c e t o i n f e c t i o u s Disease ed. by: R.H. Dunlop and H. W. Moon, pp. 61-81. Wilson,D.E* and S.M.Hirst. 1977. Ecology and f a c t o r s l i m i t i n g roan and s a b l e antelope p o p u l a t i o n s i n South A f r i c a . W i l d l . Monog. 54. Yuill>T,M. 1970. Myxomatosis and f i b r o m a t o s i s o f r a b b i t s , hares and s g u i r r e i s . I n : I n f e c t i o u s D i s e a s e s of Wild Mammals. Ed. by: J.W. Davis, L.H.Karstad and D.O.Trainer. Iowa S t a t e P r e s s , Ames. Z a r u b k i n s k i i ^ V . S . 1959. Abstr. No. 3788. S e l f p u r i f i c a t i o n of s o i l rand water from anthrax. Vet. B u l l . 30:668. 70 Appendix I . I s o l a t i o n of B a c i l l u s A n t h r a c i s Osing House I n n o c u l a t i o n For f i v e y ears, s t u d i e s of wi l d animal p o p u l a t i o n s i n Tanzania*s Selous Game Reserve r e c o g n i z e d a . non-predatory m o r t a l i t y . T h i s o c c u r r e d near a f l o o d p l a i n , towards the end of the wet season and the s t a r t of the dry season {Gainer 1979). An e a r l y i n v e s t i g a t i o n r e v e a l e d i n d i c a t i o n s of anthrax (Jakob pers. comm). S t a i n e d blood smears co n t a i n e d b a c t e r i a with the morph o l o g i c a l appearance of B. a n t h r a c i s and hide from elepha n t Loxodonta a f r i c a n a and wildebeest, Connochaetes t a u r i n u s , r e a c t e d p o s i t i v e l y to the A s c o l i t e s t ( L i n c o l n e t a l 1964). Attempts a t i s o l a t i n g the c a u s a t i v e agent were n e g a t i v e . The d i a g n o s i s of anthrax r e q u i r e s that these i n d i c a t i o n s o f the d i s e a s e be s u b s t a n t i a t e d with the i s o l a t i o n of the organism, because t h e r e a r e a l a r g e number of other e p i z o o t i c p o s s i b i l i t i e s besides anthrax (Henning 1 9 5 6 , Davis e t a l 1 9 7 0 ) ; and because these i n d i c a t i o n s o f anthrax do not d i f f e r e n t i a t e B, a n t h r a c i s from a n t h r a c o i d organisms. For our i n i t i a l attempts a t r e c o v e r i n g the organism, we took t i s s u e samples, or c o t t o n swabs and f i l t e r paper soaked i n f r e s h exudates, from nine c a r c a s s e s . These were r e f r i g e r a t e d , f o r s e v e r a l days sometimes, u n t i l they could be t r a n s p o r t e d to the b a c t e r i o l o g y s e c t i o n of the C e n t r a l V e t e r i n a r y Laboratory, Dar-es-Salaam. Here the m a t e r i a l was s u b j e c t e d t o a g e n e r a l b a c t e r i o l o g i c a l examination; i n c l u d i n g c u l t u r e f o r anaerobes. No s p e c i f i c pathogenic b a c t e r i a were found. 71 We a l s o made blood smears from the nine c a r c a s s e s , u s i n g Giemsa or Wright s t a i n s . Many of these c o n t a i n e d i n d i v i d u a l , rod-shaped b a c i l l i with prominent c a p s u l e s . In a d d i t i o n , we attempted t o i s o l a t e the organism from the environment. T h i s r e g i o n answered the d e s c r i p t i o n s of anthrax areas i n other s t u d i e s (Minett 1952, Van Ness 1971, Ebedes 1975). The suspected o r demonstrated sources o f i n f e c t i o n i n these s t u d i e s were u s u a l l y stagnant, a l k a l i n e waterholes. T h e r e f o r e , we measured the pH o f t h i s area's waterholes, and from the edges of 35 t h a t were a l k a l i n e , we took s i l t samples, a t the l a b o r a t o r y , these were d i l u t e d , heated to 80 C f o r 10 minutes, and c u l t u r e d f o r the i s o l a t i o n o f B. a n t h r a c i s . B a c i l l u s a n t h r a c i s was not recovered from any of t h i s m a t e r i a l . As a l l attempts to c u l t u r e B. a n t h r a c i s . a r e l a t i v e l y easy organism to c u l t u r e , were n e g a t i v e , we c o n s i d e r e d i t p o s s i b l e t h a t the animals were k i l l e d by other pathogenic agents and t h a t the subsequent i n v a s i o n of the c a r c a s s by such organisms as B. cereus and C l o s t r i d i u m p e r f r i n q e n s , provided the i n d i c a t i o n s of anthrax. In t h i s c l i m a t e , p u t r e f a c t i o n i s r a p i d . T h e r e f o r e , we took l a b o r a t o r y mice i n t o the f i e l d t o a s s i s t the g e n e r a l i s o l a t i o n of pathogenic organisms. T i s s u e exudates from f r e s h c a r c a s s e s of one impala, Aepyceros melampus and f o u r wildebeest were i n j e c t e d i n t o two mice per c a r c a s s . The two mice from the impala, and f i v e of the e i g h t mice from the w i l d e b e e s t , d i e d o v e r n i g h t . These mice were s e a l e d i n i n d i v i d u a l c o n t a i n e r s and f r o z e n , f o r upto 10 days, u n t i l t h e i r t r a n s p o r t to the l a b o r a t o r y . The g e n e r a l ( i n c l u d i n g anaerobic) b a c t e r i o l o g i c a l c u l t u r e o f the spleen or h e a r t b l o o d from a l l of these mice 72 produced c o l o n i e s with the c h a r a c t e r i s t i c s of a n t h r a c i s (Hummel and Gainer i n prep.). No other s p e c i f i c pathogens were rec o v e r e d . Of the th r e e mice t h a t d i d n ' t d i e , one was from a c a r c a s s from which another mouse had c o n t r a c t e d anthrax, and the other two were from another c a r c a s s . The mouse from the f i r s t c a r c a s s , and one from the second c a r c a s s , showed s i g n s of i l l n e s s . B a c i l l u s a n t h r a c i s was not recovered from c u l t u r e s o f the h e a r t blood and spleen of these animals. N e i t h e r were any other s p e c i f i c pathogens recovered from these mice. Other p u b l i s h e d accounts of anthrax i n v e s t i g a t i o n s have a l s o r e p o r t e d d i f f i c u l t y r e c o v e r i n g B. a n t h r a c i s , from c a r c a s s e s t h a t probably had been i n f e c t e d with anthrax; e s p e c i a l l y when the c o n d i t i o n s were warm as they o f t e n a re during outbreaks o f the d i s e a s e ( S t e i n 1947, S c a t t e r d a y e t a l 1954, Seto and Takizawa 1969, Toschkoff and Veljanov 1970, Lamb 1973, Fox e t a l 1977). Apparently p u t r e f a c t i v e organisms e l i m i n a t e B. a n t h r a c i s i n - the c a r c a s s , or durin g the t r a n s p o r t of specimen m a t e r i a l ( S t e i n 1947, Toschkoff and Veljanov 1970). There i s a danger of i n t e r p r e t i n g the non-recovery o f B. a n t h r a c i s from c a r c a s s e s as evidence o f the non-existence o f the d i s e a s e . But i f blood smears demonstrate rod-shaped b a c i l l i with prominent c a p s u l e s , anthrax must be s e r i o u s l y c o n s i d e r e d . These mor p h o l o g i c a l f e a t u r e s are probably the best s i n g l e c r i t e r i o n f o r the i d e n t i f i c a t i o n o f B, a n t h r a c i s ( S t e i n 1943). The use of mice apparently provided a media i n which the p r o l i f e r a t i o n of B. a n t h r a c i s e l i m i n a t e d the p u t r i f a c t i v e organisms t h a t undoubtedly contaminated the i n j e c t i o n s of 73 c a r c a s s exudates. Other p u b l i s h e d accounts of anthrax i n v e s t i g a t i o n s r e p o r t t h a t i t i s d i f f i c u l t to r e c o v e r B. a n t h r a c i s (spores) from the e x t e r n a l environment (Hinett and Dhanda 1941, H i n e t t 1950, Z a r u b k i n s k i i 1959); but l i t t l e r e s e a r c h has been s p e c i f i c a l l y aimed at e x p l a i n i n g the r o l e of environmental f a c t o r s i n the occurrence of the d i s e a s e (Gainer 1979). 74 L i t e r a t u r e c i t e d : Davis,J.W., L.H.Karstad, and D.O.Trainer.1970. I n f e c t i o u s D iseases o f Wild Mammals. Iowa S t a t e Press, Ames. Ebedes,H.1975. Anthrax e p i z o o t i c s i n the Etosha N a t i o n a l Park, South West A f r i c a . I n t . W i l d l . D i s . Conf. 3:519-528. Fox,M.D., J.M.Boyce, A.F.Kaufmann, J.B.Ioung, and H.W.Whitford.1977. An e p i z o o t i c study of anthrax i n F a l l s County,Texas. J . Am. Vet- Med. A. 170:327-333-Gainer,R.S.1979.Anthrax and w i l d e b e e s t . M.Sc.,0. of B r i t i s h Columbia. Henning,M.W.1956. Animal Diseases i n South A f r i c a . 3 ed. C e n t r a l News Agency, P r e t o r i a . Hummel,P.H., and R.S.Gainer- In prep. The d i a g n o s i s of B a c i l l u s a n t h r a c i s i n game of the Selous Game Reserve, Tanzania. Lamb,R.1973. A new loo k at i n f e c t i o u s d i s e a s e s : anthrax. B r i t . Med. J . 5846:157-160. Lincoln,R-E.., J.S.Walker, F . K l e i n and B.W.Haines.1964. Anthrax. Adv. Vet. S c i . Comp. Med. 9:327-368. H i n e t t , F.C1950. S p o r u l a t i o n and v i a b i l i t y of B a c i l l u s a n t h r a c i s i n r e l a t i o n to environmental temperatures and humidity. J . Comp. Path. Therap. 60:161-176. :—• —.1952. The annual and s e a s o n a l i n c i d e n c e of anthrax i n v a r i o u s c o u n t r i e s . C l i m a t i c e f f e c t s and s o u r c e s of i n f e c t i o n . O f f . I n t . E p i z . , B u l l . 37:238-300. — — ., and M.Biphanda.1941. M u l t i p l i c a t i o n o f B a c i l l u s a n t h r a c i s and C l o s t r i d i u m chauyoei i n s o i l and water. Ind. J . Vet. S c i . A l - Husb. 11:308-328-, S c a t t e r d a y , J . E . , A.W.Stichka and M.M-Galtons.1954. Anthrax i n F l o r i d a . Vet. Med. 49: 188-190. Seto,K. and T-Takizawa.1969- Dose-response between innoculum dose of anthrax spores and s u r v i v a l time o f mice- Natn-I n s t - Anim. Hlth- Qt. Tokyo 9:129-135. Stei n , C D . 1 9 4 3 . S t u d i e s and o b s e r v a t i o n s on the l a b o r a t o r y d i a g n o s i s of anthrax. Vet. Med. 38:130-139-— 1947. Some o b s e r v a t i o n s on the t e n a c i t y of anthrax. Vet. . Med. 42: 13-22. Toschkoff,A- and D-Veljanov.1970- S p o r u l a t i o n and v i r u l e n c e of B a c i l l u s a n t h r a c i s i n opened and unopened c a r c a s s e s . 75 A r c h i v . Exper. Vet. 24:1153-1160. Van Ness,G.B.1971. Ecology of anthrax- Science 172:1303-1307. Zarubkinskii,V.S.1959. Abstr. No. 3788. S e l f p u r i f i c a t i o n of s o i l and water from anthrax. Vet. B u l l . 30:668. 76 Appendix I I . Reproduction of female wildebeest and impala I n t r o d u c t i o n I s t u d i e d p o p u l a t i o n s of wildebeest Connochaetes t a u r i n u s and impala Aepyceros melampus i n Tanzania's S e l o u s Game Reserve from 1971-1973 (Gainer 1978). Part of t h i s study i n v o l v e d the c o l l e c t i o n o f i n f o r m a t i o n on the p r o d u c t i o n of young. The p r o d u c t i o n of young i n w i l d animal p o p u l a t i o n s i s s u b j e c t t o s e v e r a l n a t u r a l f a c t o r s t h a t appear to sy n c h r o n i z e t h e i r r e p r o d u c t i o n with the seasons (Dauphine and McClure 1974, Thomas and Cowan 1975). N u t r i t i o n v a r i e s s e a s o n a l l y , and i s known to a f f e c t , t h e f e r t i l i t y of females and the su c c e s s o f young, an examination of wild ungulate s p e c i e s , i n the same area but with d i f f e r e n t g e s t a t i o n p e r i o d s and f e e d i n g h a b i t s , i n d i c a t e s which n u t r i e n t s are important to f e r t i l i t y and newborn animals. M a t e r i a l s and methods The study area was i n southeast Tanzania; a s e m i - a r i d r e g i o n midway between the equator and the T r o p i c o f C a p r i c o r n . The year i s d i v i d e d i n t o two seasons; a warm wet season from November t o .April,, and a c o o l e r dry season from Hay t o October. Seventy female wildebeest and 40 female impala, one year o f age and o l d e r , were shot f o r post mortem examination. I evaluated t h e i r u t e r i f o r i n d i c a t i o n s of a r e c e n t p a r t u r i t i o n , and t h e i r mammary glands f o r i n d i c a t i o n s o f a r e c e n t c a l v i n g . When p r e s e n t , a f e t u s was removed, weighed, and i t s sex 77 determined. F e t a l i n f o r m a t i o n from p r e v i o u s c o l l e c t i o n s (F. Mes pers . comm.j i s a l s o used. In a d d i t i o n , the o v a r i e s from s e v e r a l wildebeest were removed and examined f o r s t r u c t u r e s i n d i c a t i v e of t h e i r past and present r e p r o d u c t i v e s t a t u s (Appendix I I I ) . R e s u l t s Uterus and mammary gland examinations Of the 70 wildebeest examined, 62 were c o l l e c t e d a t a time when a f e t u s was expected to be present and o a c r o s c o p i c a l l y a p p r e c i a b l e . Of these 62 animals, a l l of 50 mature animals, and 6 of 12 y e a r l i n g s , had f e t u s e s ; 26 i n the l e f t horn and 30 i n the r i g h t -E i g h t wildebeest were c o l l e c t e d when they weren't expected to have a m a c r o s c o p i c a l l y v i s i b l e f e t u s , but w i t h i n e i g h t weeks of the l a s t mean c a l v i n g date- Six of the s i x mature animals, and one of the two y e a r l i n g s , had evidence of a r e c e n t p a r t u r i t i o n . Of the 26 mature and 14 y e a r l i n g impala examined, a l l cont a i n e d a f e t u s ; 39 i n the l e f t horn and one i n the r i g h t -Ovarian examinations Eleven wildebeest were c o l l e c t e d w i t h i n 5 months o f the p r e v i o u s c a l v i n g season. S i x of seven mature, and three of f o u r y e a r l i n g s , c o n t a i n e d o v a r i e s with pigmented s c a r s d e r i v e d from c o r p o r a l u t e a o f a p r e v i o u s season pregnancy (Appendix I I I ) . A l l e i g h t mature and y e a r l i n g animals c o l l e c t e d between the 78 p e r i o d o f Febuary 11 and A p r i l 19 (both years combined) con t a i n e d o v a r i e s with f o l l i c l e s i n d i c a t i v e of e s t r u s c y c l e a c t i v i t y (Appendix I I I ) . F e t a l examinations The 56 wildebeest and 40 impala f e t u s e s were a l l s i n g l e , and a p p a r e n t l y normal. The r a t i o of male to female, of the f e t u s e s whose sex c o u l d be determined, was 32:23 f o r w i l d e b e e s t , and 22:14 f o r impala. Maximum weights (male and female r e s p e c t i v e l y ) were 20.7 and 18.4 kilograms f o r w i l d e b e e s t , and 4.6 and 4.4 kilograms f o r impala. The average b i r t h weights, based on maximum f e t a l weights and minimum newborn animal weights, were c o n s i d e r e d to be 20.0 kilograms f o r wildebeest and 4-5 k i l o g r a m s f o r impala. Assuming t h a t the g e s t a t i o n p e r i o d f o r these wildebeest i s the same as f o r c a p t i v e w i l d e b e e s t of the same s p e c i e s , (253 days; A s d e l l 1964), the Hugget and Widdas (1951): formulae f o r t h i s p o p u l a t i o n i s : W1/3 = 0.121 ( t - 2 3 ) . T h i s r e l a t i o n s h i p , between the cube r o o t s of wildebeest f e t a l weights and t h e i r date of c o l l e c t i o n (a sample s i z e of 60), p r e d i c t s a mean b i r t h date o f December 18 and a mean c o n c e p t i o n date of A p r i l 11 ( F i g 1).. On the b a s i s of t h i s r e l a t i o n s h i p ' s c o n f i d e n c e l i m i t s (Sokal and Bohlf 1969:446), 95% of t h e f e t u s e s were conceived w i t h i n a 29 day p e r i o d (March 26 t o A p r i l 24). An a n a l y s i s of c o v a r i a n c e between the 1969, 1970, 1971, 1972, and 1973 r e l a t i o n s h i p s d i d not have h i g h enough p r o b a b i l i t i e s to r e j e c t t h e n u l l h y p o t h e s i s t h a t they were not d i f f e r e n t from t h e i r combined r e l a t i o n s h i p . The year with the l a r g e s t and most e v e n l y spread sample (1972) 79 F i g u r e 1. Hugget and Widdas s t y l e r e g r e s s i o n s of the cube r o o t s o f wildebeest f e t a l weights (grams) a g a i n s t t h e i r c o l l e c t i o n - d a t e s ; using a combination of f i v e years (1969-1973) data and using only the 1972 data-There i s a 10 day d i f f e r e n c e i n p r e d i c t e d c o n c e p t i o n weights, and the 95% c o n f i d e n c e l i m i t s of the combined r e l a t i o n s h i p i s p l u s 14 days and minus 15 days. Day 1 i s January 1. 81 had an estimated 10 days l a t e r time of con c e p t i o n and an estimated 3 days e a r l i e r time o f b i r t h than the combined d a t e s . Assuming 196 days f o r the g e s t a t i o n p e r i o d of impala ( F a i r a l l 1969), the Hugget and Widdas (1951) formulae f o r t h i s p o p u l a t i o n i s : W 1 / 3 = 0.091(t-16). T h i s r e l a t i o n s h i p , between the cube r o o t s of impala f e t a l weights and t h e i r dates of c o l l e c t i o n (a sample s i z e of 33), p r e d i c t s a mean b i r t h date o f October 9 and a mean conception date o f March 27 ( F i g 2). On the b a s i s o f t h i s r e l a t i o n s h i p ' s c o n f i d e n c e l i m i t s , 95% of the f e t u s e s were conceived w i t h i n a 40 day pe r i o d (March 8 to A p r i l 17). An a n a l y s i s of covar i a n c e r e v e a l e d t h a t the 1971, 1972 and 1973 r e l a t i o n s h i p s d i d not have high enough p r o b a b i l i t i e s t o r e j e c t the n u l l h y p o t h e s i s t h a t they were d i f f e r e n t from t h e i r combined r e l a t i o n s h i p . The year with the l a r g e s t and most uniform sample (1972) had an estimated s i x days l a t e r time o f c o n c e p t i o n and two days l a t e r time o f b i r t h . D i s c u s s i o n The d i s p r o p o r t i o n a t e l y g r e a t e r number of male f e t u s e s f o r both wildebeest and impala i s i n keeping with the g e n e r a l trend i n wild ungulate p o p u l a t i o n s ( S a d l i e r 1969), with other wildebeest s t u d i e s (Talbot and T a l b o t 1963, Watson 1969, Braack 1973), but not with three other impala s t u d i e s ( F a i r a l l 1969). The o v e r a l l pregnancy r a t e o f wildebeest (Table 1) i s s l i g h t l y h igher than S e r e n g e t i ' s and Kruger's. The f e r t i l i t y of these o t h e r p o p u l a t i o n s may have been reduced by t h e i r b r u c e l l o s i s i n f e c t i o n s (Sachs e t a l 1968, Vos and Niekerk 1967), 82 F i g u r e 2. Hugget and Hiddas s t y l e r e g r e s s i o n s o f the cube r o o t s of impala f e t a l weights (grams) a g a i n s t t h e i r c o l l e c t i o n dates; using a combination of three years (1971-1973) d a t a and using only the 1972 data. There i s a s i x day d i f f e r e n c e i n the p r e d i c t e d c o n c e p t i o n weights, and the 95% c o n f i d e n c e l i m i t s of the combined r e l a t i o n s h i p i s p l u s 19 days and minus 21 . days. Day 1 i s January 1. 8k Table 1. The 1970-1973 pregnancy r a t e of Selous wildebeest, the v a r i o u s sources of pregnancy .Information, and the pregnancy r a t e o f S e r e n g e t i ( f i r s t : T a l b o t and T a l b o t 1963; second: Hatson 1969) and Kruger (Braack 197 3) wi l d e b e e s t . Mature Y e a r l i n g Fetus 50/50 6/12 Pregnancy sc a r 6/7 3/4 Uterus and Mammary Gland 6/6 1/2 O v e r a l l 62/63 10/18 Selous 98.4 55.6 S e r e n g e t i 1 95.0 83.0 S e r e n g e t i 2 96-0 37.0 Kruger 93.3 32.3 85 a d i s e a s e t h a t i s a p p a r e n t l y not present i n Selous ungulate p o p u l a t i o n s appendix V I ) . , The pregnancy r a t e of impala, 100% f o r both mature and y e a r l i n g i s h i g h e r than f o r o t h e r p o p u l a t i o n s (Dasmann and Hossman 1962, F a i r a l l 1969), although i t may be higher i n the r e g i o n of the equator where impala have two c a l v i n g seasons and some females f i r s t c o nceive as c a l v e s (Kayanja 1969). The pregnancy r a t e f o r wildebeest and impala two years o f age and, o l d e r , i s higher than the average f o r range c a t t l e (Stoddart e t a l 1975); e s p e c i a l l y of a f r i c a n range c a t t l e (Peacock e t a l 1971). I t i s a l l the more remarkable c o n s i d e r i n g the s h o r t p e r i o d of conception of the w i l d ungulate p o p u l a t i o n s . But y e a r l i n g pregnancy r a t e s f o r these w i l d ungulate p o p u l a t i o n s i s o f t e n lower./ That i s , t h e r e i s an a s s o c i a t i o n between a female's a b i l i t y t o reproduce and her a b i l i t y t o s u r v i v e d u r i n g her second year o f l i f e i n the w i l d . The Hugget and Widdas formula f o r Selous wildebeest i s c o n s i d e r a b l y d i f f e r e n t from t h a t o f S e r e n g e t i wildebeest (Watson 1969).The S e r e n g e t i formula i s based on a g e s t a t i o n p e r i o d o f 240 days o b t a i n e d from f i e l d o b s e r v a t i o n , whereas t h i s study used the g e s t a t i o n p e r i o d of c a p t i v e wildebeest, a l s o the S e r e n g e t i formula i s based on a 10% h e a v i e r b i r t h weight; even though S e r e n g e t i wildebeest a r e the s m a l l e r s u b s p e c i e s (Lydekker 1926) . The Hugget and Widdas formula f o r Selous impala i s c o n s i d e r a b l y d i f f e r e n t from t h a t of Kruger's ( F a i r a l l 1969). The g e s t a t i o n p e r i o d s are both based on t h e same c a p t i v e impala g e s t a t i o n p e r i o d , but the Kruger formula uses a 20% h e a v i e r 86 average b i r t h weight. T h i s i s i n keeping with the l a r g e r s i z e of the Kruger impala (Lydekker 1926). I t i s obvious t h a t b i r t h weights are q u i t e v a r i a b l e . T h e r e f o r e , I used the g e s t a t i o n p e r i o d s r a t h e r than b i r t h weights f o r p r e d i c t i o n of b i r t h d a tes. B i r t h weights p r e d i c t e d 4 day and 3 day l a t e r b i r t h dates f o r wildebeest and impala i n the Selous. The most important d i e t a r y n u t r i e n t s f o r ; range c a t t l e f e r t i l i t y a r e energy, phosphorous and Vitamin A (Haynard and L o o s l i 1969, Stoddart et a l 1975). T h e i r maximum l e v e l s i n c a t t l e ranges occur when the g r a s s i s l u s h and green (Stoddart e t a l 1975). The p r e d i c t e d c o n c e p t i o n dates were e s s e n t i a l l y the same f o r wildebeest and impala. That i s , towards the end of the wet season. At t h i s time of year, both s p e c i e s had been i n the s h o r t grass h a b i t a t f o r s e v e r a l months g r a z i n g l u s h , green s h o r t grass (Hodgers 1976). I n e f f e c t , t h i s regime mimics a domestic animal f l u s h i n g regime (Stoddart e t a l . 1975). In c o n j u n c t i o n with the f a c t t h a t mature males e s t a b l i s h t e r r i t o r i e s (throughout the year f o r wildebeest) i n the s h o r t g r a s s h a b i t a t , t h i s i n d i c a t e s the importance of an abundant supply of s h o r t green grass (and probably the high l e v e l s of vi t a m i n A, phosphorus, and energy a s s o c i a t e d with green grass) t o t h e i r breeding regime. The nourishment of newborn w i l d ungulates i s p r i m a r i l y from t h e i r mother's milk, which tends t o be adequate even though a mother's d i e t may be t e m p o r a r i l y inadequate ( S a d l i e r 1969). But w i t h i n weeks, newborns depend on t h e i r h a b i t a t f o r an adequate d i e t . The d i e t a r y n u t r i e n t most a s s o c i a t e d with the suc c e s s o f 87 nursing mother and young range c a t t l e i s p r o t e i n . (Maynard and L o o s l i 1969, Stoddart et a l 1975). P r o t e i n reaches i t s maximum l e v e l s i n c a t t l e ranges e a r l y i n the wet season when the grass i s growing r a p i d l y (Stoddart e t a l 1975). In t h i s s t u d y , wildebeest c a l v i n g o c c u r r e d at a time when the wet season i s normally s t a r t i n g . By the time the c a l v e s are an average o f a few weeks o l d and s t a r t t o graze, t h e i r f orage would have a high p r o t e i n l e v e l . The average date of b i r t h f o r impala i n t h i s study was two months b e f o r e the wet season normally begins. At t h i s time of year, the p r o t e i n l e v e l s i n c a t t l e ranges are r e l a t i v e l y low. But a t t h i s time of year, leguminous A c a c i a spp. pods f a l l t o the ground i n the u s u a l impala h a b i t a t (Gwynne 1969). I n s t e a d of g r a z i n g d u r i n g t h i s p e r i o d , impala browse and consume these pods (Gwynne 1969, Bodgers 1976). T h i s d i e t may a c t u a l l y have adequate p r o t e i n f o r impala. The times of b i r t h and c o n c e p t i o n of a l l the p o p u l a t i o n s o f wildebeest and impala s t u d i e d i n the southern hemisphere (Lamprey 1963, T a l b o t and T a l b o t 1963, F a i r a l l 1969, Braack 1973, Andere 1975) are approximately the same and are c o i n c i d e n t with s i m i l a r s easonal events. T h i s i s an i n d i c a t i o n of the importance o f the s e a s o n a l v a r i a t i o n of d i e t a r y n u t r i e n t s to the l i f e h i s t o r y s t r a t e g y o f these s p e c i e s . Both c o n c e p t i o n dates i n the Selous were e s s e n t i a l l y the same; at times when the s p e c i e s had the highest p r o b a b i l i t y of r e c e i v i n g an adequate l e v e l of what are probably the t h r e e most important n u t r i e n t s a f f e c t i n g t h e i r f e r t i l i t y . By c o n t r a s t , the p a r t u r i t i o n dates were q u i t e d i f f e r e n t ; a t times when the 88 p r o b a b i l i t y o f r e c e i v i n g an adequate l e v e l of the n u t r i e n t most important to the s u r v i v o r s h i p of the newborns was much l e s s . T h i s suggests t h a t f e r t i l i t y i s more dependent on adequate n u t r i t i o n than the r e a r i n g of younq. E s t e s (1976) suggests t h a t the s h o r t e r c a l v i n g p e r i o d i n h i s mobile-aggregate p o p u l a t i o n was p r i m a r i l y t o reduce the c a l f l o s s e s to hyaenas. The hyaena p o p u l a t i o n was r e l a t i v e l y minor i n t h i s study (Gainer 1979), ye t the c a l v i n g p e r i o d s were very s h o r t . T h i s suggests that the s h o r t c a l v i n g p e r i o d s may gain t h e i r s e l e c t i v e advantage by a d j u s t i n g to the n u t r i e n t regime r a t h e r than from by r e d u c i n g c a l f l o s s e s t o hyaenas. S e k u l i c (1978) a l s o thought t h a t c a l v i n g synchrony was not i m p o r t a n t i n r e d u c i n g predatory m o r t a l i t y . 89 L i t e r a t u r e c i t e d : Andere,D.K. 1975. The dynamics of pa s t u r e use by wildebeest (and c a t t l e ) i n the Amboseli b a s i n . M.Sc., 0". of N a i r o b i . , A s d e l l , S . A . 1964. P a t t e r n s of Mammalian Beproduction. C o n s t a b l e and Co., Lond. Braack,H. 1973- P o p u l a t i o n dynamics of the blue wildebeest Connochaetes t a u r i n u s ( B u r c h e l l 1823),.• i n the c e n t r a l d i s t r i c t o f the Kruger N a t i o n a l Park.!V<K/ruger. N a t i o n a l Park r e p o r t . Dasmann,B.F. and A-S.Mossman. 1962. Po p u l a t i o n s t u d i e s of impala i n southern Rhodesia. J . Mammal. 43:375-395. Dauphine,T.C. and R.L.McClure. 1974.: Synchronous mating i n Canadian barren-ground c a r i b o u . J . W i l d l . Manage. 38:54-66. Estes,R.D. 1976. The s i g n i f i c a n c e o f breeding synchrony i n the wildebeest.. E. A f r . W i l d l . J . , 14:135-152. , F a i r a l l , N . 1969. P r e n a t a l development o f the impala Aepyceros melampus L i c h t . Koedoe 12:97-103. Gainer,R.S. 1979. Anthrax and wildebeest. M.Sc., U. of B r i t i s h Columbia. Gwynne,M.D. 1969. Notes on the n u t r i t i v e values of Acacia pods i n r e l a t i o n t o A c a c i a seed d i s t r i b u t i o n by ungulates. E. A f r . w i l d l . J . 7:176-178-Huggett,A- St G. and W-f.Widdas. 1951. The r e l a t i o n s h i p between mammalian f o e t a l weight and c o n c e p t i o n age. J . P h y s i o l . 114:306-317. Jarman,S-V. 1976. Impala s o c i a l behavior; b i r t h behavior. E. Afr- W i l d l . J . 14:153-168. Kayanja, F.I.B. 1969. The ovary of the impala Aepyceros melampus ( L i c h e n s t e i n 1812). J . Reprod. F e r t . Suppl. 6:311-317. Lamprey,H-F-.1963- A study of the ecology of the mammal p o p u l a t i o n s of a game re s e r v e i n the A c a c i a savanna o f Tanganyika, with p a r t i c u l a r r e f e r e n c e t o animal numbers and biomass. D. P h i l . , 0. of Oxford. Lydekker,R. 1926. The Game Animals of A f r i c a Rowland Ward, Lond. Maynard,L. A. and J . K . L o o s l i . 1969. Animal N u t r i t i o n . HcGraw H i l l , New York. Peacock,F.M., M.Roger, W.G.Kirk, E.M.Hodges and A.C.Warnick. 1971. Reproduction i n Brahman, Shorthorn and c r o s s b r e d cows on d i f f e r e n t pasture programs. J . Animal S c i . 33:458-465. 90 lodgers,W.A- 1976. Seasonal d i e t p r e f e r e n c e s of impala from South East Tanzania. E. A f r . W i l d l . J . 14:331-333. Sachs,B., C.Staak and G.M-Groocock. 1968- S e r o l o g i c a l i n v e s t i g a t i o n s of b r u c e l l o s i s i n game animals i n Tanzania. B u l l . E p i z . D i s . A f r . 16:93-100. Sadlier,R.M.F.S. 1969. The Ecolgoy of Beproduction i n Wild and Domestic Mammals. Metheun, Lond. S e k u l i c , R. 1978. ,• S e a s o n a l i t y of r e p r o d u c t i o n i n s a b l e an t e l o p e . E. A f r . W i l d l . J . 16: 177-182-Sokal,B.B. and F.J.Rohlf-,1969- B i o m e t r i c s - Freeman and co., San F r a n c i s c o . Stoddart,L.A., A.D.Smith and T.R.Box. 1975. Range Management- 3 ed. McGraw H i l l , New York. Talbot,L.M. and M.H.Talbot.,1963. The wildebeest of western Masailand, East A f r i c a . W i l d l . Monog. 12. Thomas,D.C. and I.NcT.Cowan. 1975. The p a t t e r n of r e p r o d u c t i o n i n female Columbian b l a c k - t a i l e d deer, O d o c o i l e u s hemionus columbianus. J . Reprod. F e r t . 44:261-272-, VosyV.de, and C.A-W.J.Niekerk. 1969. B r u c e l l o s i s i n Kruger N a t i o n a l Park. J . S. A f r . Vet. Med. Ass. 40: 331-339. Watson,B.M. 1969- Beproduction of w i l d e b e e s t Connochaetes t a u r i n u s a l b o j u b a t u s Thomas, i n the S e r e n g e t i r e g i o n and i t s s i g n i f i c a n c e to c o n s e r v a t i o n . J . Reprod- Fert- Suppl. 6:287-310. 9 1 Appendix I I I . The I n t e r p r e t a t i o n of Pregnancy from wildebeest As p a r t of a p o p u l a t i o n study of wildebeest Connachaetgs t a u r i n u s i n Tanzania's Selous Game Reserve, I determined i t s pregnancy r a t e (Gainer 1979). The pregnancy s t a t u s of an animal i s c u s t o m a r i l y determined by performing a post mortem examination f o r an embryo or f e t u s . But o f t e n the number o f post mortem examinations does not p r o v i d e a l a r g e enough sample s i z e ; e s p e c i a l l y when comparisons are made w i t h i n the sample (eg. between age c l a s s e s or h a b i t a t c o n d i t i o n s ) . Another source of pregnancy i n f o r m a t i o n i s the o v a r i e s . Present and past pregnancies are represented by s t r u c t u r e s w i t h i n these organs. A p r e v i o u s wildebeest study used o v a r i a n s t r u c t u r e s f o r t h i s purpose (Watson 1969), but adeguate c r i t e r i a f o r t h e i r i n t e r p r e t a t i o n were not presented. I removed and s t o r e d i n 10% f o r m a l i n the o v a r i e s from 24 animals, one year of age or o l d e r . L a t e r they were s l i c e d u s ing a r a z o r blade so t h a t the body of the ovary was completely exposed i n s a g g i t a l s e c t i o n s , 1-2 mm t h i c k , while remaining adhered t o the h i l a r borders. I m a c r o s c o p i c a l l y examined each s e c t i o n f o r r e l e v a n t o v a r i a n s t r u c t u r e s ; r e c o g n i z e d from t h e i r d e s c r i p t i o n s i n other ungulate s p e c i e s (Morrison 1960, Spinage O v a r i e s I n t r o d u c t i o n M a t e r i a l s and methods 92 1969, Dauphine 1978). Ovarian s t r u c t u r e s were grouped i n t o t h r e e c a t e g o r i e s ; l a r g e f o l l i c l e s (diameters of 5 mm or more), l u t e a l bodies, and pigmented s c a r s ( F i g 1). I examined r e p r e s e n t a t i v e s of the d i f f e r e n t types of l u t e a l bodies and pigmented s c a r s u s i n g a standard method f o r o v a r i a n h i s t o l o g y ( p a r a f f i n embedding and Masson's Trichome s t a i n ; Thomas 1970). I n a d d i t i o n , I h i s t o l o g i c a l l y examined t h i r t e e n of the l a r g e r pigmented s c a r s using a f r o z e n t i s s u e method ( f r e e z i n g microtome and f r o z e n t i s s u e s t a i n ; Bray 1975). Based on f e t a l weights and t h e i r dates of c o l l e c t i o n , I knew t h a t 95% of the p o p u l a t i o n had conceived w i t h i n 15 days of A p r i l 11, and that the mean c a l v i n g date was December 18 (Appendix I I ) . The comparison of these dates with the date o f c o l l e c t i o n of an animal permitted the e s t i m a t i o n of the probable stage o f development of the o v a r i a n s t r u c t u r e s . R e s u l t s Wildebeest o v a r i e s , without any l a r g e e s t r u s c y c l e s t r u c t u r e s , are approximately 5x10x20 mm. T h e i r e x t e r n a l appearance, as w e l l as the e x t e r n a l appearance of the u t e r u s , p l a c e n t a and g e n i t a l i a , resembled the d e s c r i p t i o n of these organs f o r c a t t l e Bos t a u r u s (Arthur 1964) .. Larger f o l l i c l e s F o l l i c l e s with a diameter of 5-10 mm were present i n animals c o l l e c t e d throughout the year. The e l e v e n animals c o l l e c t e d d u r i n g Febuary, March and A p r i l , the approximate p e r i o d of 93 F i g u r e 1. R e p r e s e n t a t i v e s of s t r u c t u r e s seen i n c r o s s s e c t i o n s (X3) of Selous wildebeest o v a r i e s . A. Corpus luteum of pregnancy ( l i g h t brown) . B. Regressing corpus luteum of an unconceived o v u l a t i o n ( b r i g h t y e l l o w ) . C, D, and E. Pigmented s c a r s o f corpus luteum o f pregnancy. C. Estimated to be two months post partum ( l i g h t brown). D. Estimated t o be s i x months post partum (deep brown). E. Estimated t o be one year post partum (dark brown). 9k 95 breeding a c t i v i t y , tended to have more of these f o l l i c l e s (two t o s i x with a mean of 3.1) than the t h i r t e e n animals c o l l e c t e d d u r i n g the r e s t of the year (zero t o two with a mean of 0.62). The f i v e animals that c o n t a i n e d f o l l i c l e s with diameters o f 11-14 mm c o n t a i n e d one of these f o l l i c l e s each. With one e x c e p t i o n , these animals were c o l l e c t e d i n l a t e February and March. The one e x c e p t i o n was an animal, estimated to be 24 months o l d , c o l l e c t e d during the c a l v i n g p e r i o d . I t had two l a r g e f o l l i c l e s with diameters of 10 mm and 14 mm. L u t e a l s t r u c t u r e s Seventeen animals c o n t a i n e d s t r u c t u r e s with the e x t e r n a l c h a r a c t e r i s t i c s o f proper corpus luteum ( F i g 1) - Each animal c o n t a i n e d one corpus luteum; e i g h t occurred i n the l e f t o v a r i e s and nine i n the r i g h t o v a r i e s . T h e i r oblong dimensions averaged 12x18 mm. The e l e v e n animals with an embryo or f e t u s a l l had a corpus luteum. The m i c r o s c o p i c examination of one of these s t r u c t u r e s using the standard h i s t o l o g i c a l method r e v e a l e d c h a r a c t e r i s t i c l u t e a l t i s s u e (Thomas 1970, Dauphine 1978).These two s t r u c t u r e s were a l s o examined using the f r o z e n t i s s u e method. Two animals, c o l l e c t e d a t approximately the p e r i o d of b r e e d i n g a c t i v i t y , c ontained l u t e a l s t r u c t u r e s with the b r i g h t yellow c o l o r t y p i c a l of r e g r e s s i n g c o r p o r a l u t e a of unconceived o v u l a t i o n s (Arthur 1964, Spinage 1969).They were accompanied i n t h e i r o p p o s i t e o v a r i e s with a proper corpus luteum i n one, and a 12 mm f o l l i c l e i n the other. The m i c r o s c o p i c examination of these l u t e a l s t r u c t u r e s , using the standard h i s t o l o g i c a l method, r e v e a l e d degenerated 96 l u t e a l c e l l s with p y k n o t i c n u c l e i i and poor c e l l u l a r d e f i n i t i o n ; c h a r a c t e r i s t i c s of r e g r e s s i n g c o r p o r a l u t e a o f unconceived o v u l a t i o n s (Dauphine 1978). Two l u t e a l s t r u c t u r e s had c h a r a c t e r i s t i c s of secondary corpora l u t e a (Dauphine 1978). Both were i n animals c o l l e c t e d a t approximately the time of the breeding season. One had a diameter of 10 mm and appeared t o be an unruptured f o l l i c l e with a t h i c k e n e d l i n i n g . I t was accompanied by a yellow s c a r i n the same ovary and a corpus luteum i n the o p p o s i t e ovary. The o t h e r unusual l u t e a l s t r u c t u r e had a diameter of 6 mm, a grey c o l o r , and the macroscopic appearance of a small l u t e a l body with a c e n t r a l c a v i t y . A proper c o r p o r u s luteum was present i n the o p p o s i t e ovary. I t s examination using the standa r d h i s t o l o g i c a l method revealed d i f f u s e c o n n e c t i v e t i s s u e and po o r l y d e f i n e d c e l l s with p y k n o t i c n u c l e i i . , Pigmented s c a r s Two of these s t r u c t u r e s , i n two d i f f e r e n t animals c o l l e c t e d at approximately the time of the r u t , had a b r i g h t y ellow appearance s i m i l a r t o t h a t d e s c r i b e d above f o r r e g r e s s i n g c o r p o r a l u t e a o f unconceived o v u l a t i o n s . T h e i r dimensions were 2x3x5 mm and 2x3x4 mm. The h i s t o l o g i c a l examination of the s m a l l e r one, using the f r o z e n t i s s u e method, r e v e a l e d degenerated l u t e a l t i s s u e a d j a c e n t t o a r e l a t i v e l y minor c o l l e c t i o n of blood v e s s e l s ( F i g 2) . These s c a r s were i d e n t i f i e d as r e g r e s s i n g c o r p o r a l u t e a o f unconceived o v u l a t i o n s approximately one month o l d e r than those p r e v i o u s l y d e s c r i b e d as l u t e a l s t r u c t u r e s . 9 7 F i g u r e 2. A yellow pigmented s c a r (2x3x4 mm) of a r e g r e s s i n g corpus luteum of an unconceived o v u l a t i o n from the ovary o f a wildebeest c o l l e c t e d approximately one month a f t e r the breeding p e r i o d (X200). The f r o z e n t i s s u e method demonstrates a degenerated l u t e a l body ( i t shows poor c e l l u l a r d e f i n i t i o n , p a r t i a l l y because i t d i d not s e c t i o n w e l l ) . The pigment grannules and the t h i c k n e s s of the. blood v e s s e l w a l l s are not remarkable. F i g u r e 3.. Brown pigmented s c a r (2x3x4 mm) of a former corpus luteum of pregnancy estimated to be f i v e months post partum (X150); from the same animal as i n F i g u r e 2. The most c h a r a c t e r i s t i c f e a t u r e demonstrated by the f r o z e n t i s s u e method i s the large.number of t h i c k -w a l l e d blood v e s s e l s i n c o n j u n c t i o n with many dark g r a n u l e s . 9 9 T h i r t y two other pigmented s c a r s were r e c o g n i z e d i n twenty animals c o l l e c t e d throughout the year. They had varying shades of brown. The mi c r o s c o p i c examination of two brown s c a r s from animals c o l l e c t e d two and f o u r months f o l l o w i n g the c a l v i n g p e r i o d , u s i n g the standard h i s t o l o g i c a l method, r e v e a l e d a c o l l e c t i o n of degenerated l u t e a l t i s s u e , c o n n e c t i v e t i s s u e , and t h i c k walled blood v e s s e l s c h a r a c t e r i s t i c of s c a r s of proper c o r p o r a l u t e a (Golley 1957, Thomas 1970, Dauphine 1978). The s i z e and shade of brown of these s c a r s was r e l a t e d t o the time of year when, the animal was c o l l e c t e d . animals c o l l e c t e d two months a f t e r the c a l v i n g p e r i o d c o n t a i n e d s c a r s t h a t were approximately 2x4x6 mm and a p a l e brown c o l o r , animals c o l l e c t e d f o u r months a f t e r the c a l v i n g p e r i o d c o n t a i n e d s c a r s t h a t were approximately 2x3x4 mm and a darker brown c o l o r -animals c o l l e c t e d e i g h t , nine, ten and elev e n months a f t e r the c a l v i n g p e r i o d c o ntained s c a r s t h a t were approximately 1x2x3 mm and a very dark brown c o l o r -S e v e r a l of the s e animals had s m a l l e r brown s c a r s as w e l l -Some were minute and d i f f i c u l t t o r e c o g n i z e . Even though I estimated t h a t f i v e animals were seven t o ten y e a r s o l d , the g r e a t e s t number of brown s c a r s r e c o g n i z e d i n an animal was f i v e . T h i s i s f a r fewer than would be expected i f these females had as high a pregnancy r a t e i n the past as was observed i n t h i s study (appendix II) -The examination of twelve of the l a r g e r o f these brown s c a r s u sing the f r o z e n t i s s u e method r e v e a l e d areas with prominent dark grannules adjacent t o a l a r g e c o l l e c t i o n o f t h i c k w a l l e d blood v e s s e l s . I i d e n t i f i e d these as s c a r s of proper 100 cor p o r a l u t e a . One (Fig....3) was from the animal c o l l e c t e d f i v e months f o l l o w i n g the c a l v i n g p e r i o d t h a t a l s o c o ntained the yellow s c a r i n F i g u r e 2. Both of these s c a r s were approximately the same s i z e , but with s t r i k i n g d i f f e r e n c e s i n t h e i r h i s t o l o g y . D i s c u s s i o n No animal i n t h i s study had more than one f o l l i c l e with a diameter g r e a t e r than 11 mm. Host of the animals with a f o l l i c l e diameter of 11 mm or more o c c u r r e d i n animals c o l l e c t e d d u r i n g the b r e e d i n g p e r i o d . T h i s suggests t h a t a f o l l i c l e diameter of 11 mm. o r more i s i n d i c a t i v e of p r o e s t r u s or e s t r u s . The only other time a f o l l i c l e of t h i s s i z e o ccurred was i n a 24 month o l d animal c o l l e c t e d during the c a l v i n g p e r i o d . The c a l v i n g a c t i v i t y may have induced e s t r u s i n t h i s s e x u a l l y mature, yet unconceived animal. Near the time of breeding a c t i v i t y , t h r e e animals had both r e g r e s s i n g c o r p o r a l u t e a of unconceived o v u l a t i o n s and proper corpus luteum; and one animal had a r e g r e s s i n g c o r p o r a l u t e a of an unconceived o v u l a t i o n and a p r o e s t r u s f o l l i c l e . The s i l e n t heat p a t t e r n of r e p r o d u c t i o n i s a s s o c i a t e d with p a i r e d o v u l a t i o n s (Thomas and Cowan 1975, E.McEwan p e r s . comm.) , and has been proposed f o r w i l d e b e e s t (Watson 1969). Whether wi l d e b e e s t a c t u a l l y do have a s i l e n t heat p a t t e r n of r e p r o d u c t i o n or not r e q u i r e s f u r t h e r i n v e s t i g a t i o n . 101 The two secondary corpora l u t e a appeared t o be the r e s u l t of d i f f e r e n t processes. The c y s t with the thickened l i n i n g i s s i m i l a r to the d e s c r i p t i o n of unovulated f o l l i c l e s t h a t l u t e i n i z e a t t h e same time as the proper c o r p o r a l u t e a (Dauphine 1978). The second one composed of c o n n e c t i v e t i s s u e with a c e n t r a l c a v i t y i s s i m i l a r t o the d e s c r i p t i o n f o r a p a r t i a l l y r e g r e s s e d corpus luteum from a p r e v i o u s e s t r u s t h a t l u t e i n i z e d again with the f o l l o w i n g corpus luteum of pregnancy (Dauphine 1978). The f a c t t h a t secondary c o r p o r a l u t e a were not seen i n animals c o l l e c t e d l a t e r i n the year suggests t h a t these s t r u c t u r e s may only p e r s i s t f o r the i n i t i a l stages o f a pregnancy i n wi l d e b e e s t . The i d e n t i f i c a t i o n and d i f f e r e n t i a t i o n o f these s t r u c t u r e s can be u s e f u l i f they are i n d i c a t i o n s of present or past pregnancies. When an animal i s pregnant* a proper corpus luteum i s p r e s e n t . But corpus luteum are present a f t e r every o v u l a t i o n r e g a r d l e s s of whether a co n c e p t i o n o c c u r s or not. A corpus luteum o f a con c e p t i o n tends t o be l a r g e r (Spinage 1969, Markgren 1969), but t h e r e are no c r i t e r i a e s t a b l i s h e d y e t f o r the ready d i f f e r e n t i a t i o n o f these two s t r u c t u r e s . T h i s means t h a t the presence of a corpus luteum cannot be used as a d e f i n i t e i n d i c a t i o n of a pregnancy, but t h a t the absence of a corpus luteum can be used as a d e f i n i t e i n d i c a t i o n o f a non-pregnancy. A corpus luteum t h a t p e r s i s t s f o r the period o f a pregnancy develops a pigmented s c a r t h a t i s d i f f e r e n t from the pigmented s c a r of a corpus luteum t h a t only p e r s i s t e d f o r the p e r i o d o f an e s t r u s (Cheatum 1949, G o l l e y 1957, Spinage 1969, Dauphine 1978). 1 0 2 In t h i s study, the two s c a r s of r e g r e s s i n g c o r p o r a l u t e a of unconceived o v u l a t i o n s had a b r i g h t yellow c o l o r , and the 13 r e g r e s s i n g c o r p o r a l u t e a of pregnancy had a brown c o l o r . The number of m a c r o s c o p i c a l l y v i s i b l e brown s c a r s i s not a r e l i a b l e i n d i c a t i o n of the number of past pregnancies i n o l d e r animals. In t h i s and other s t u d i e s (Cheatum 1949, G o l l e y 1957, Simkin 1965, Spinage 1969, Markgren 1969) macroscopic evidence of brown s c a r s disappeared a f t e r about f i v e y e a r s of t h e i r e x i s t e n c e . The r e l i a b l e i n t e r p r e t a t i o n of t h e i r presence or absence a f t e r a few years of e x i s t e n c e r e q u i r e s m i c r o s c o p i c examinations of s t a i n e d s e r i a l s e c t i o n s (Thomas 1970, Dauphine 1978) . Furthermore, c o l o r i s not a r e l i a b l e f e a t u r e f o r d i f f e r e n t i a t i o n of pigmented s c a r s {Golley 1957^ Morrison 1960, Markgren 1969). They are r e a d i l y d i f f e r e n t i a t e d though, u s i n g the f r e e z i n g microtome and f r o z e n t i s s u e s t a i n . Those of c o r p o r a l u t e a of unconceived o v u l a t i o n s have p a r t i a l l y degenerated l u t e a l t i s s u e , and the a s s o c i a t e d blood v e s s e l s and d a r k l y pigmented g r a n u l e s a r e r e l a t i v e l y unremarkable ( F i g 2). S c a r s o f r e g r e s s i n g c o r p o r a l u t e a of pregnancy are c h a r a c t e r i z e d by a c o l l e c t i o n of l a r g e , dark grannules adjacent t o s e v e r a l , t h i c k w a l l e d b l o o d v e s s e l s ( F i g . 3 ) . I t would appear then, t h a t the r e l a t i v e l y r a p i d and easy h i s t o l o g y using the f r e e z i n g microtome and f r o z e n t i s s u e s t a i n can be used t o d i f f e r e n t i a t e s c a r s of c o r p o r a l u t e a of pregnancy from s c a r s of corpora l u t e a of unconceived o v u l a t i o n s . But c r i t e r i o n f o r the i d e n t i f i c a t i o n of the s c a r s of secondary corpo r a l u t e a has not been e s t a b l i s h e d . Presumably these s c a r s 1 0 3 are c o n s i d e r a b l y s m a l l e r than the proper corpus luteum from the same pregnancy (Arthur 1964, Morrison 1960, Dauphine 1978). For purposes of the p o p u l a t i o n study, I used pigmented s c a r s t o i n d i c a t e a past pregnancy i n a l i m i t e d manner. The prescence or absence o f a s c a r of a proper corpus luteum of pregnancy, i d e n t i f i e d using the f r o z e n t i s s u e method, i n d i c a t e d the pregnancy s t a t u s during the previous year, of seven o l d e r animals c o l l e c t e d w i t h i n f i v e months of the l a s t c a l v i n g p e r i o d . I t was c o n s i d e r e d t h a t the l a r g e s i z e and l i g h t c o l o r a t i o n of f i v e . month o l d or l e s s pregnancy s c a r s d i f f e r e n t i a t e d them from o l d e r s c a r s , and t h e i r l a r g e s i z e d i f f e r e n t i a t e d them from p o s s i b l e s c a r s of secondary corp o r a l u t e a of the same pregnancy. Furthermore, there i s no known example of w i l d e b e e s t c o n c e i v i n g as c a l v e s . T h e r e f o r e , i t was assumed t h a t the presence or absence of a l a r g e s c a r of a corpus luteum of pregnancy, i d e n t i f i e d using the f r o z e n t i s s u e method, i n f o u r animals, two to t h r e e years o l d , was a r e l i a b l e i n d i c a t i o n o f t h e i r pregnancy s t a t u s as y e a r l i n g s . Because of the s m a l l sample s i z e (24 a n i m a l s ) , the o b s e r v a t i o n s made i n t h i s study are t e n t a t i v e . More o v a r i e s , e s p e c i a l l y from around the time of breeding a c t i v i t y , are needed to more c l e a r l y e s t a b l i s h the s t a t u s o f the secondary and unconceived l u t e a l s t r u c t u r e s and t h e i r s c a r s (Morrison 1965). 104 L i t e r a t u r e c i t e d : Arthur,G.H. 1964. Wright's V e t e r i n a r y O b s t e t r i c s . , B a l l i e r e , T i n d a l l and Cox, London. Bray rW.E.,1975. C l i n i c a l Laboratory Methods. 6 ed. Mosby Co., St. L o u i s . Cheatum,E.L. 1949- The use of c o r p o r a l u t e a f o r determining o v u l a t i o n i n c i d e n c e and v a r i a t i o n i n the f e r t i l i t y of w h i t e - t a i l e d deer. C o r n e l l Vet. 39:282-291. Dauphine,T.C- 1978- Morphology of the barren-ground c a r i b o u ovary. Can. J . Z o o l . 56:1684-1696. Gainer, R.S. 1979. Anthrax and w i l d e b e e s t . M.Sc., 0. of B r i t i s h Columbia. Go l l e y , P . B. 1957. An a p p r a i s a l of o v a r i a n analyses i n determining r e p r o d u c t i v e performance of b l a c k - t a i l e d deer. J . W i l d l . Mgmt. 21:62-65. Markgren,G. 1969. Reproduction of moose A l c e s a I c e s i n Sweden. V i l t r e v y 6:127-299. Morrison,J.A. 1960. Ovarian c h a r a c t e r i s t i c s i n e l k of known breed i n g h i s t o r y . J . W i l d l . Manage. 24:297-307. Simkin,D.W. 1965. Reproduction and p r o d u c t i v i t y of moose i n northwestern O n t a r i o . J . W i l d l . Manage. 29:740-750. Spinage,C.A. 1969. Reproduction i n the Uganda Defassa waterbuck Kobus def a s s a ugandae Neumann. J . Reprod. P e r t . 18:445-458. Thomas,D.C. 1970. The ovary, r e p r o d u c t i o n and p r o d u c t i v i t y of female Columbian b l a c k - t a i l e d deer. Ph.D., U. B r i t i s h Columbia. — • ., and I.McT. Cowan. 1975. The p a t t e r n of r e p r o d u c t i o n i n female Columbian b l a c k - t a i l e d deer, O d o c o i l e u s hemionus columbianus. J . Reprod. P e r t . 44:261-272. Watson,R.H. 1969. Reproduction of wildebeest Connochaetes t a u r i n u s a l b o j u b a t u s Thomas i n the S e r e n g e t i r e g i o n and i t s s i g n i f i c a n c e t o c o n s e r v a t i o n . , J . Reprod. P e r t . Suppl. 6:287-310. 1 0 5 Appendix IV. Age d e t e r m i n a t i o n methods f o r wildebeest I n t r o d u c t i o n Age d e t e r m i n a t i o n methods f o r ungulates a r e c u s t o m a r i l y based on tooth examinations. They may u t i l i z e e r u p t i o n p a t t e r n s , s u r f a c e wear p a t t e r n s , s i z e measurements, and i n c r e m e n t a l l i n e s (Spinage 1973). As p a r t of a p o p u l a t i o n study of wildebeest Connochaetes t a u r i n u s i n Tanzania's Selous Game Reserve (Gainer 1979), I e s t a b l i s h e d the ages of a sample on the b a s i s of i n c r e m e n t a l l i n e s i n t h e i r cementum. From t h i s sample, we developed more p r a c t i c a l methods o f age d e t e r m i n a t i o n . M a t e r i a l s and methods One hundred and s i x t y f i v e s k u l l s from shot animals, and 1,269 picked-up s k u l l s , were c a t e g o r i z e d a c c o r d i n g t o c r i t e r i a used i n p r e v i o u s l y d e s c r i b e d schedules f o r t o o t h e r u p t i o n and s u r f a c e wear p a t t e r n s by T a l b o t and T a l b o t (1963) and Watson (Stobart 1970). I n a d d i t i o n * I used c a l i p e r s t o measure the enamel h e i g h t s of the b u c c a l cusps of the two f i r s t and two t h i r d m a x i l l a r y molars. The enamel he i g h t of o l d e r animals was u s u a l l y approximated because i t was covered with a heavy l a y e r o f cementum. I h i s t o l o g i c a l l y examined 86 p a i r s of m a x i l l a r y f i r s t molars. These i n c l u d e d the 20 o l d e s t animals from the c o l l e c t i o n o f picked-up s k u l l s and the r e s t came from the c o l l e c t i o n of shot animals. P r i o r t o d e c a l c i f i c a t i o n , the r o o t s , from the 1 0 6 c o l l e c t i o n of shot animals. P l u s f i v e m i l l i m e t e r s of crown, were removed u s i n g a s m a l l hacksaw. These r o o t s were then p l a c e d i n 25 ml. of 4 percent h y d r o c h l o r i c a c i d . T h i s s o l u t i o n was renewed d a i l y u n t i l the r o o t s were p l i a b l e and e a s i l y trimmed with a razor, b l a d e . Trimmed segments were s e c t i o n e d i n the d e s i r e d p o s i t i o n using a f r e e z i n g microtome ( M i l l e r 1974). From each segment, I took ten 10-16 mu s e c t i o n s a t approximately 100 mu i n t e r v a l s . These were prepared using a f r o z e n t i s s u e s t a i n composed p r i m a r i l y of t o l u i d i n e blue (Bray 1975; Thomas 1977), and then a l l s e c t i o n s from the same segment were mounted on the same s l i d e . Some s e c t i o n s t h a t c u r l e d were f l a t t e n e d with a subbing s o l u t i o n (1 gm of g e l a t i n , 0.1 gm chromium potassium s u l f a t e i n 1 1 o f d i s t i l l e d water). C o v e r s l i p s were attached with permount. A l l the s e c t i o n s on a s l i d e were f i r s t scanned a t 40 X. Those with reasonably r e g u l a r and d i s c r e t e l i n e s were then counted a t 100X. S t a t i s t i c a l a n a l y s i s was done a c c o r d i n g to Sokal and B o h l f (1969). R e s u l t s The h i s t o l o g y of wildebeest t e e t h was t y p i c a l of an ungulate ( M i l l e r 1974), with prominent l i n e s i n the cementum (F ig . 1# 2, and 3). The c h a r a c t e r i s t i c s of these l i n e s v a r i e d s u b s t a n t i a l l y a c c o r d i n g t o the r o o t used, i t s s u r f a c e , and the p o s i t i o n i n which i t was s e c t i o n e d . The b e s t s e c t i o n s were from the l i n g u a l s u r f a c e of e i t h e r of the l i n g u a l r o o t s (the protocone and the hypocone; Spinage 1973).The b e s t e v a l u a t i o n of the i r r e g u l a r i t i e s and d i s c o n t i n u i t i e s i n the l i n e s was 107 F i g u r e 1. A f i r s t molar from a Selous wildebeest estimated t o be 12 mouths o l d (X100). One d i s t i n c t and continuous l i n e i s v i s i b l e i n the ou t e r c e l l u l a r cementum and i n n e r periodontum. F i g u r e 2- A f i r s t molar from a Selous wildebeest estimated to be 24 months o l d (X150). Two d i s t i n c t and c o n t i n o u s l i n e s a r e v i s i b l e i n the c e l l u l a r cementum- The outer l i n e appeared to be continuous with periodontum and was p a r t i a l l y detached during the removal of the too t h . F i g u r e 3 . One of the two f i r s t molars from S e l o u s w i l d e b e e s t with the maximum number of recognized l i n e s (X120). T h i r t e e n l i n e s were r e c o g n i z e d . 108 p e r i o d o n t u m i n c r e m e n t a l l i n e c e l l u l a r cementum a c e l l u l a r cementum G r a n n u l a r fail ot d e n t i n e 109 provided by examining the roo t l o n g i t u d i n a l l y , from s l i g h t l y above where the enamel met the r o o t to the t i p of the r o o t . The l e n g t h of time between d e c a l c i f i c a t i o n and s t a i n i n g appeared t o i n f l u e n c e the prominence of the l i n e s . The sooner the s l i d e s were prepared a f t e r d e c a l c i f i c a t i o n , the e a s i e r the l i n e s tended t o be t o i n t e r p r e t . I n t e r p r e t a t i o n s of the number of l i n e s between s e c t i o n s from the same t o o t h were o f t e n d i f f e r e n t , e s p e c i a l l y i n o l d e r animals. Those s e c t i o n s t h a t had rea s o n a b l y r e g u l a r and d i s c r e t e l i n e s were chosen f o r c o u n t i n g . Sine of the 86 p a i r s of f i r s t molars d i d not have any s e c t i o n s t h a t were c o n s i d e r e d a c c e p t a b l e . Host of these were from animals t h a t were a p p a r e n t l y q u i t e o l d . Of the remaining 77, only 7 c o n t a i n e d more than e i g h t l i n e s . The maximum number of l i n e s recognized was 13 ( F i g - 3). Double l i n e s were o c c a s i o n a l l y r e c o g n i z e d , but they o c c u r r e d only i n i s o l a t e d s e c t i o n s t h a t were i n c o n s i s t e n t with other s e c t i o n s from the same animal. These were c o n s i d e r e d to be technique a r t i f a c t s (Spinage 1973) and were not i n c l u d e d i n the counts. Compared with s e v e r a l s p e c i e s of North American ungulates, the i n c r e m e n t a l l i n e s i n wildebeest are g e n e r a l l y more d i f f i c u l t t o i n t e r p r e t ; e s p e c i a l l y when t h e r e i s more than f o u r o r f i v e l i n e s present. T h i s was a l s o e v i d e n t when they were examined using u l t r a v i o l e t f l o r e s c e n t microscopy (H. Gasaway pers. comm.) and i n ground s e c t i o n s ( J . E l l i o t p ers. comm.), A comparison of the r e l a t i o n s h i p between cementum l i n e counts of s i x o r l e s s l i n e s and enamel height, and o f the r e l a t i o n s h i p between cementum l i n e counts of seven or more l i n e s 110 and enamel height was made using an a n a l y s i s of c o v a r i a n c e (cementum l i n e counts were transformed using l o g a r i t h m s t o the base 10) . The n u l l h ypothesis t h a t the r e l a t i o n s h i p s were the same was not r e j e c t e d . T h i s suggests t h a t the d i f f i c u l t y of i n t e r p r e t i n g s e c t i o n s with more than s i x l i n e s r e l a t i v e t o the i n t e r p r e t a t i o n of the s e c t i o n s with s i x or l e s s . l i n e s d i d not b i a s the r e s u l t s s u b s t a n t i a l l y . The probable ages of young s h o t animals was known, because based on f e t a l weights, I knew t h a t 95 percent of the p o p u l a t i o n was conceived w i t h i n 15 days of A p r i l 11 (Appendix II) , and the body and horn development of c a l v e s , y e a r l i n g s , e a r l y two year o l d s and mature animals was e a s i l y d i s t i n g u i s h e d (Talbot and T a l b o t 1963, S t o b a r t 1970). On t h i s b a s i s , a dark outer zone was v i s i b l e i n the c e l l u l a r cementum of two 10 month o l d animals, a complete l i n e ( F i g . 1) was v i s i b l e i n two animals 12 months o l d , one animal 16 months o l d and one animal 18 months o l d ; one complete l i n e and one outer dark zone were v i s i b l e i n one 24 month o l d animal ( F i g . 2 ) , and two complete l i n e s were v i s i b l e i n two 26 month o l d animals. These f i n d i n g s i n d i c a t e t h a t one l i n e i s formed i n the f i r s t molars each year d u r i n g the f i r s t two years of the animal's l i f e . R e g r e s s i o n l i n e s were made o f the r e l a t i o n s h i p s between the ages p r e d i c t e d u sing the p r e v i o u s l y d e s c r i b e d e r u p t i o n and s u r f a c e wear s c h e d u l e s , and cementum l i n e c o u n t s . The f i r s t r e l a t i o n s h i p assumed that the number of cementum l i n e s p r e d i c t e d age. on the b a s i s of one l i n e per year, the second on the b a s i s of two l i n e s per year. The p r e v i o u s s c h e d u l e s s l i g h t l y o v e restimated age u s i n g the f i r s t assumption* and g r o s s l y 111 overestimated age using the second assumption. The examination of s e c t i o n s o f c a l f and y e a r l i n g t e e t h i n d i c a t e d t h a t the i n c r e m e n t a l l i n e had been formed by the e l e v e n t h month of the animal's year. T h i s meant t h a t the average age based upon ab s o l u t e cementum l i n e v a l u e s , s i x months a f t e r the formation o f the l i n e , would be when the .animal was i n the f i f t h month of the f o l l o w i n g year, or 0.4 of a year more than the absolute cementum l i n e v alue. A r e g r e s s i o n l i n e was made between these ages and the average enamel h e i g h t s of the f i r s t and t h i r d molar ( F i g . 4). T h e i r c o r r e l a t i o n c o e f f i c i e n t s were 0.92 f o r the f i r s t molar and 0.82 f o r the t h i r d molar. Based on t h i s r e l a t i o n s h i p (y = 61 - 53.2 logx) , I c a l c u l a t e d the 95% c o n f i d e n c e l i m i t s of the cementum age p r e d i c t e d using enamel hei g h t (Sokal and Bohlf 1969:446), and the range of enamel hei g h t f o r each year c l a s s (Table 1). Using the ages p r e d i c t e d from cementum l i n e counts, the schedule f o r the e r u p t i o n and s u r f a c e wear p a t t e r n s of m a x i l l a r y t e e t h i s given i n F i g u r e 5. The r e l a t i o n s h i p between the ages of 1,434 s k u l l s , p r e d i c t e d using t h i s schedule and p r e d i c t e d using enamel h e i g h t , was improved s u b s t a n t i a l l y when the average age of the s i x t h category ( F i g . 5) was reduced from a mean of 3 to 2.5 y e a r s . The only major d i f f e r e n c e between the schedule i n F i g u r e 5 and Watson's (Stobart 1970) was the l a s t category. Watson c o n s i d e r e d i t t o r e p r e s e n t almost 10 more years of age. The r e g r e s s i o n i n F i g u r e 4 c l o s e l y approximated the model f o r the r a t e o f tooth wear (Spinage 1973) when a f i r s t molar, with a h e i g h t of 54 mm at age one, was completely worn down at age 13; i . e . the formula was y=54(1 - (t/12) */?) ( F i g . 6 ) . T h i s 1 1 2 F i g u r e 4. The r e l a t i o n s h i p between the transformed (logarithms to the base 10) cementum l i n e age (the number of cementum l i n e s p l u s 0.4) and the average enamel he i g h t s ( m i l l i m e t e r s ) of the b u c c a l cusps of the f i r s t and t h i r d molars from Selous wildebeest. The r e g r e s s i o n l i n e i s c a l c u l a t e d from the c o r r e l a t i o n a n a l y s i s of the r e l a t i o n s h i p (y = 61 - 53.2 l o g x) . A l s o i n c l u d e d i s t h e range ( v e r t i c a l l i n e s ) , sample s i z e ("n"), and standard d e v i a t i o n s ( c r o s s marks on ranges with sample s i z e s g r e a t e r than four) f o r each year c l a s s examined. 114 Table 1. The range i n age, based on the 95% c o n f i d e n c e l i m i t s of the c o r r e l a t i o n a n a l y s i s of the f i r s t molar r e s u l t s , and the ranges of the enamel h e i g h t s (the average o f both bucc a l cusps f o r both s i d e s of the maxilla) f o r the f i r s t and t h i r d molars from Selous wildebeest t h a t were a s s o c i a t e d with the cementum l i n e age r e l a t i o n s h i p i n F i g u r e 4. Age C l a s s Range of Age F i r s t Molar T h i r d Molar , 1 . 1.1 —; 2-2 56.0 — 45.0 2 1.7 3.4 44.9 - 35.8 3 2-4 - 4.9 35.7 - 29-0 61.5 - 51.6 4 3.2 - 6. 3 28.9 - 24.0 51-5 45-0 5 3.8 7-5 23.9 - 19.8 44-9 - 38.9 6 4.5 - 9.0 19.7 - 16.2 38.8 - 34.0 7 5.4 10.7 16.1 - 13.0 33.9 29.6 8 6.1 . - 12.2 12.9 10.5 29-5 •:T-. 26.4 9 6.7 13.3 10.4 •- 8.0 26-3 •- 23.2 10 7.3 - 14.5 7-9 - 5.8 23. 1 -. 19.4 11 7.9 •- 15.8 5-7 - 3.8 19.3 16.4 12 8.6 17.2 3.7 - 2-0 16.3 14.2 13 9.0 18.0 1.9 - 0.0 14. 1 11.6 14 11.5 - 9. 1 115 F i g u r e 5. The ages a s s o c i a t e d with the e r u p t i o n and s u r f a c e wear of the m a x i l l a r y t o o t h row of Selous w i l d e b e e s t . The e s t i m a t i o n of the ages of animals l e s s than 2-5 years o l d was based p r i m a r i l y on t h e time of year when the animal was shot r e l a t i v e to i t s estimated time o f b i r t h . The e s t i m a t i o n of the ages of animals 2.5 years o l d or more was based on cementum l i n e counts. premolars m o j a r 10 months. First molar i s worn. The f i r s t molar erupts at about five months. 12 months. 18 months. ^ permanent premolar 20 months. 26 months (range 20-26 months). Permanent premolars erupted. 2.5 years (range 2-A years). 5 years (range 3-6 years). 7 years (range 6-10 years). 8 years (two animals both 8 years). 10 years (range 7-13 years). 12 years (two animals 11 and 13 years). 117 F i g u r e 6. Comparison of the enamel height of Selous wildebeest with ages based on cementum l i n e counts and with ages based on an a p p r o p r i a t e t o o t h wear model (y = 54(1 - (t/12)»/ 2). 119 agrees with our f i n d i n g s t h a t two animals with e s s e n t i a l l y no enamel l e f t on t h e i r f i r s t molars had 11 and 13 i n c r e m e n t a l l i n e s . The age d i s t r i b u t i o n above suggests t h a t probably the maximum age of a wildebeest i n t h i s environment i s about 15 ye a r s ; which accords w e l l with t h e i r maximum age observed i n c a p t i v i t y (20.5 years; fiubb 1960, Talbot and Ta l b o t 1963, Crandal 1965). D i s c u s s i o n Comparisons of cementum l i n e counts i n f i r s t molars with t h r e e age p r e d i c t i o n s ; i n c l u d i n g the known ages of two year o l d and younger animals, the ages using p r e v i o u s l y d e s c r i b e d e r u p t i o n and s u r f a c e wear t r e n d s , and the ages using an a p p r o p r i a t e model of t o o t h wear; i s s u b s t a n t i a l evidence o f a one i n c r e m e n t a l l i n e per year r e l a t i o n s h i p . T h i s study was at a l a t i t u d e midway between the equator and the T r o p i c of C a p r i c o r n where t h e r e was e s s e n t i a l l y one wet and one dry season per year. Other s t u d i e s of in c r e m e n t a l l i n e s i n the cementum of ungulate t e e t h a t t h i s l a t i t u d e , or f u r t h e r south, a l s o have a one l i n e per year r e l a t i o n s h i p (Steenkamp 1975, The r e l i a b l e and e a r l y e r u p t i o n time of the f i r s t molar, i n c o n j u n c t i o n with the time of f o r m a t i o n of the in c r e m e n t a l l i n e , was an important f a c t o r i n a c o n s i s t e n t one-to-one, l i n e per year r e l a t i o n s h i p . C e l l u l a r cementum, and consequently the in c r e m e n t a l l i n e s t h a t i t c o n t a i n s , i s formed a f t e r the e r u p t i o n of the t o o t h (Spinage 1973). The f i r s t molar i n wildebeest e r u p t s a t approximately f i v e months of age and the fo r m a t i o n of the dark zone commences a t approximately 8 months of age. T h i s 120 t o o t h i s the only tooth that has a r e l a t i o n s h i p of one l i n e per year of l i f e o f the animal. In a d d i t i o n , i t s e r u p t i o n time r e l a t i v e t o the time of formation of the i n c r e m e n t a l l i n e would be more c o n s i s t e n t than f o r any other t o o t h . The r e g r e s s i o n l i n e between enamel height and age ( F i g . 4) i s much steeper than t h a t g i v e n by : Watson (Stobart 1970). P a r t i a l l y t h i s i s because the f i r s t molars i n S e r e n g e t i wildebeest, i n keeping with t h e i r o v e r a l l body s i z e , are s m a l l e r than t h i s study's s u b s p e c i e s (A. S i n c l a i r pers, comm.).Also i t was because Watson's b a s i s of one l i n e per year i n the d e n t i n e of ground s e c t i o n s o f t h i r d molars p r e d i c t e d much o l d e r ages; as much as t h r e e years (24 years of age) beyond the maximum observed age of wildebeest i n c a p t i v i t y . The m i c r o s c o p i c examination of the cementum of h i s t o l o g i c a l l y prepared f i r s t molars of other ungulate s p e c i e s a t t h i s l a t i t u d e has a two l i n e s per year r e l a t i o n s h i p (Spinage 1976) The c o r r e l a t i o n c o e f f i c i e n t o f the r e l a t i o n s h i p between f i r s t molar enamel height and cementum l i n e age was h i g h , y e t the p r e d i c t i o n o f age using enamel h e i g h t measurements had wide c o n f i d e n c e l i m i t s (Table 1). T h i s i s l a r g e l y because of the v a r i a b i l i t y o f the s i z e and wear of t e e t h w i t h i n a p o p u l a t i o n , and between sexes (Flook 1970). Some would be because of the i n a c c u r a t e (but a p p a r e n t l y unbiased) i n t e r p r e t a t i o n of cementum l i n e counts. Using known age a n i m a l s , t h i s i n a c c u r a c y was found t o be s u b s t a n t i a l i n moose A Ices a l c e s (Gasaway e t a l 1978) ; a s p e c i e s with i n c r e m e n t a l l i n e s t h a t are more e a s i l y i n t e r p r e t e d than w i l d e b e e s t . Although c o u n t i n g cementum l i n e s i s the most p r e c i s e method 121 of d e termining age, i t i s very c o s t l y and time consuming. For a p o p u l a t i o n a n a l y s i s , the measurement of enamel he i g h t or the schedule f o r the appearances of the teeth row i s much more p r a c t i c a l . I t i s l e s s p r e c i s e , but t h i s i m p r e c i s i o n would i n t r o d u c e l i t t l e b i a s i n l a r g e sample s i z e s . Cementum l i n e counts are probably not even worthwhile f o r e s t a b l i s h i n g enamel h e i g h t age d e t e r m i n a t i o n methods f o r o t h e r wildebeest s u b s p e c i e s , or c l o s e l y r e l a t e d s p e c i e s , c o n s i d e r i n g how p r e c i s e l y the t o o t h wear model p r e d i c t e d age.. A l l t h a t i s r e g u i r e d t o c o n s t r u c t t h i s model i s the enamel height of the f i r s t molar a t one year o f age and the maximum expected d u r a t i o n of the t o o t h i n the c o n d i t i o n s of the p o p u l a t i o n (Spinage 1973). For i n s t a n c e , the enamel h e i g h t of the f i r s t molars a t one year of age of S e r e n g e t i wildebeest averages 48 mm (A. S i n c l a i r pers. comm.). T h e r e f o r e , enamel he i g h t measurements would be expected t o be 11% l e s s than those i n Table 1, or they can be c a l c u l a t e d from: y = 48(1 - ( t / 1 2 ) * / 2 ) , o r , as i n F i g u r e 4, y = 53 - 46.2 l o g x. 122 L i t e r a t u r e c i t e d : Bray,W. E. 1975- C l i n i c a l L a boratory Methods- 6 ed- Mosby Co., S t . L o u i s . Crandal,L. S. 1965. Records o f A f r i c a n antelopes i n the New York Z o o l o g i c a l Park. I n t . Zoo. Yb. 5:52-55. Flook,D.R.1970. A study o f sex d i f f e r e n t i a l i n the s u r v i v a l of w a p i t i . Canadian W i l d l i f e S e r v i c e Report 11, Ottawa. Gasaway,W.C., D.p.Harness, and R.A.Rausch.1978. Accuracy o f moose age d e t e r m i n a t i o n from i n c i s o r cementum l a y e r . J . W i l d l . Manage. 42:558-563. M i l l e r , F . L . 1 9 7 4 . B i o logy of the Kaminuriak p o p u l a t i o n of b a r r e n -ground c a r i b o u . Canadian W i l d l i f e S e r v i c e Report 31, Ottawa. Morris,P.1972. A review of mammalian age d e t e r m i n a t i o n methods. Mammalia Rev. 2:69-104. Rubb,G.B.1960. L o n g e i v i t y r e c o r d s f o r mammals a t the Chicago Z o o l o g i c a l gardens. J . Mammal. 41: 113-114. Sokal,R.R. and F.J.Rohlf.1969. B i o m e t r i c s . Freeman and Co., San F r a n c i s c o . Spinage,C.A.1973. A review of A f r i c a n t e e t h ageing methods. E. A f r . W i l d l . J . 11:165-187. - — — • - 1976. Incremental cementum l i n e s i n the t e e t h of t r o p i c a l A f r i c a n mammals- J . Z o o l - , Lond. 178:117-131. Steenkamp,j.P.G.1975. G u i d e l i n e s t o the use of d e n t a l h i s t o l o g y i n w i l d l i f e r e s e a r c h . J . S. A f r . W i l d l . Manage. Ass. 5:89-94. Stobart,P.T.1970. Ecology of the Nyasa wildebeest, L i c h e n s t e i n h a rtebeest and the southern impala i n the e a s t e r n Selous. Tanzanian Game D i v i s i o n Miombo Research Center Report, Dar-es-Salaam. Talbot,L.M. and M.H.Talbot.1963- The wildebeest i n western Masailand, East A f r i c a . W i l d l . Monog. 12. Thomas,D .C.1977. Metachromatic s t a i n i n g of d e n t a l cementum f o r mammalian age determinations. J . W i l d l . Manage. 41:207-210. 123 Appendix V. The E s t i m a t i o n of Wildebeest and Impala D e n s i t i e s Using V e h i c l e T r a n s e c t s I n t r o d u c t i o n Methods f o r the e s t i m a t i o n of animal numbers have been reviewed by Caughley (1977) and Eberhardt (1978a). The method of c h o i c e f o r p o p u l a t i o n s i n open h a b i t a t s i s a e r i a l census (Caughley 1977)-However, i t i s d i f f i c u l t t o observe most animal s p e c i e s from t h e a i r i n woodland h a b i t a t s . Approximately h a l f of A f r i c a south of the Sahara i s covered with a savanna woodland commonly r e f e r r e d to as the miombo or bush ( A n s e l l 1971).Almost a l l of the c o n t i n e n t ' s w i l d ungulate p o p u l a t i o n s are c o n t a i n e d w i t h i n t h i s h a b i t a t . The most p r a c t i c a l method of c e n s u s i n g these p o p u l a t i o n s i s with a v e h i c l e . I f the area of a p o p u l a t i o n ' s d i s t r i b u t i o n and the d e n s i t y of animals i n a r e p r e s e n t a t i v e v e h i c l e t r a n s e c t a r e known, the p o p u l a t i o n ' s numbers can be estimated. The area o f a p o p u l a t i o n ' s d i s t r i b u t i o n can u s u a l l y be mapped to s c a l e using reconnaissance. But the e s t a b l i s h m e n t of the d e n s i t y of animals i n a t r a n s e c t r e q u i r e s i n d i r e c t t e c h n i q u e s . The best technique f o r o b t a i n i n g a d e n s i t y e s t i m a t e from a t r a n s e c t i s t o c a l i b r a t e the t r a n s e c t when the d e n s i t y of the p o p u l a t i o n i s known. On the b a s i s of these r e s u l t s , t r a n s e c t r e s u l t s can be equated with p o p u l a t i o n d e n s i t y (fiobinette e t a l 1974). In most s i t u a t i o n s , however, a t r a n s e c t p o p u l a t i o n with a 124 known d e n s i t y i s not a v a i l a b l e . Other methods of e s t i m a t i n g d e n s i t y attempt to measure the v i s i b i l i t y o f the t r a n s e c t p o p u l a t i o n . Using a measure of v i s i b i l i t y , the area covered d u r i n g a t r a n s e c t can be d e r i v e d . Knowing the area covered and the number of animals counted, i t i s a simple matter to c a l c u l a t e p o p u l a t i o n d e n s i t y . , Two approaches to the measurement of v i s i b i l i t y have been taken. One i s to measure the d i s t a n c e s from the t r a n s e c t a t which the animals, or s u i t a b l e i m i t a t i o n s , d i s a p p e a r i n the environment ( H i r s t 1969, Bobinette e t a l 197.4). Another i s based on the d i s t r i b u t i o n of d i s t a n c e s a t which groups are s i g h t e d (Hemingway 1971, Burnham and Anderson 1976, Eberhardt 1978a). A convenient frame of r e f e r e n c e i s a graph of c a t e g o r i e s of r i g h t -angle s i g h t i n g d i s t a n c e s (Eberhardt 1968).The s i g h t i n g d i s t a n c e method of e s t i m a t i n g d e n s i t y i s the s i m p l e s t and most p r a c t i c a l . In the eastern r e g i o n of Tanzania's Selous Game Reserve, the Lug'onya B i v e r has c r e a t e d a d i v e r s i t y of h a b i t a t s . Contained w i t h i n the miombo woodland of the s u r r o u n d i n g c o u n t r y s i d e , patches of open s h o r t g r a s s h a b i t a t near the r i v e r ' s f l o o d p l a i n a l t e r n a t e with l i g h t woodland (Combretum spp^ dominated) and thornbush (Acacia spp. and T e r m i n a i i a spp./dominated) h a b i t a t . T h i s d i v e r s i t y of v e g e t a t i o n types a p p a r e n t l y accounts f o r the e x i s t e n c e of l a r g e p o p u l a t i o n s of s e v e r a l ungulate s p e c i e s . Wildebeest Connochaetes t a u r i n u s occupied the s h o r t grass h a b i t a t and the edges of adjacent l i g h t woodland d u r i n g the November to A p r i l wet season. During the May t o October dry season they tended to move i n t o the miombo woodland. Impala 125 Aepyceros melampus occupied areas of l i g h t woodland and thornhush, and the edges of s h o r t g r a s s r e g i o n s . From 1971-1973 we performed a survey to determine the s i z e of the wildebeest and impala p o p u l a t i o n s i n t h i s r e g ion (Gainer 1979). Based on the freguency d i s t r i b u t i o n o f s i g h t i n g d i s t a n c e c a t e g o r i e s , we present formulas f o r the c a l c u l a t i o n o f the e f f e c t i v e area observed during a t r a n s e c t , the c a l c u l a t i o n of c o n f i d e n c e l i m i t s f o r a d e n s i t y e s t i m a t e , and the c a l c u l a t i o n of sample s i z e f o r a predetermined degree of accuracy. M a t e r i a l s and Methods During the reconnaissance used f o r the mapping of the d i s t r i b u t i o n s of the wildebeest and impala p o p u l a t i o n s , t h r e e v e h i c l e t r a c k s r e p r e s e n t a t i v e o f these d i s t r i b u t i o n s were s e l e c t e d . Using these t r a n s e c t s , wildebeest were counted f o r 20 c o n s e c u t i v e months and impala were counted f o r the 6 months of both wet seasons. T r a n s e c t s were d r i v e n at approximately 30 k i l o m e t e r s per hour using an open-backed long-wheel based l a n d r o v e r . The d r i v e r and r e c o r d e r s a t i n the f r o n t and t h r e e observers stood i n the back. When a group o f animals was observed, we recorded the estimated r i g h t - a n g l e d i s t a n c e (to the nearest 100 meter) from the t r a n s e c t t o where the group was f i r s t observed. The r i g h t -angle s i g h t i n g d i s t a n c e was by f a r the most convenient measure. We f r e g u e n t l y checked these e s t i m a t i o n s by pacing them o f f ; a procedure t h a t improved t h e i r accuracy. B i n n o c u l a r s were used to a s s i s t the counting of animals. I f 126 the number of animals i n a group was i n q u e s t i o n , we l e f t the t r a n s e c t and drove c l o s e r t o the group. R e s u l t s In t o t a l we observed 3,830 groups of wildebeest and 3,084 groups o f impala. The s i z e of the wildebeest groups ranged from 1-r185 animals; with an average o f 16.5 per o b s e r v a t i o n . F i f t y -three percent o f the o b s e r v a t i o n s were of s o l i t a r y males. Impala groups ranged from 1-300 animals, with an average o f 9.5 per o b s e r v a t i o n . T h i r t y - t h r e e percent of the o b s e r v a t i o n s were of s o l i t a r y males. S o l i t a r y male wildebeest r e s t r i c t e d t h e i r a c t i v i e s t o a much s m a l l e r home range than s o l i t a r y male impala. Wildebeest t e r r i t o r i e s averaged 0.5 sg km and most were maintained throughout the year. Wildebeest are much l a r g e r and darker than impala. In a d d i t i o n , w i l d e b e e s t tended t o occupy more open h a b i t a t than impala. Where the ve g e t a t i o n p e r m i t t e d , s o l i t a r y male wildebeest c o u l d be seen a t d i s t a n c e s of 800 meters o r more. The average s i g h t i n g d i s t a n c e o f a l l wildebeest o b s e r v a t i o n s was 255 meters. S o l i t a r y male impala were seldom seen a t d i s t a n c e s o f more than 200 meters. The average s i g h t i n g d i s t a n c e : of a l l impala o b s e r v a t i o n s was 126 meters.; The number of s i g h t i n g s i n each d i s t a n c e category i s given i n Table 1. A curve i s f i t t e d t o t h e i r f r e g u e n c i e s i n F i g u r e 1. T a b l e 1. The number o f o b s e r v a t i o n s a t each s i g h t i n g a v e r a g e (av.)., s t a n d a r d d e v i a t i o n ( S.D.), and s t a n d a r d e r r o r o f the mean (S.D.) f o r distance c a t e g o r y ( m e t e r ) , t h e i r t o t a l ( t o t . ) , c o e f f i c i e n t o f v a r i a t i o n (C.V.; p e r c e n t a g e ) , w i l d e b e e s t and i m p a l a . C a t e g o r y 0 100 200 300 400 500 600- 700 800 900 1000 t o t . av. S.D. C V . S.E. W i l d e b e e s t 348 913 885 733 425 228 140 78 55 16 9 3830 255.4 185 73 2.99 Impala 924 1183 522 272 120 32 22 9 3084 125.7 124 99 2.25 128 F i g u r e 1. The d i s t r i b u t i o n of the f r e q u e n c i e s of the s i g h t i n g d i s t a n c e c a t e g o r i e s f o r the Selous wildebeest and impala groups observed dur i n g t r a n s e c t s , 1971-1973-They approximate h a l f normal d i s t r i b u t i o n s of data grouped i n t h i s f a s h i o n . 130 D i s c u s s i o n Hemingway (1971,1973) obtained s i g h t i n g d i s t a n c e s of impala and other ungulates from t r a n s e c t s i n l i g h t l y wooded areas. These t r a n s e c t s were performed on f o o t and the r i g h t - a n g l e d i s t a n c e from the t r a n s e c t to the s i g h t i n g was measured to the c l o s e s t meter. The freguency of h i s s i g h t i n g d i s t a n c e s had the usual h a l f normal d i s t r i b u t i o n . The t r a n s e c t s i n t h i s study were performed i n a l i g h t woodland, or a w o o d l a n d - r e s t r i c t e d open h a b i t a t . They were done i n a v e h i c l e using p r e s c r i b e d v e h i c l e t r a c k s , and the s i g h t i n g d i s t a n c e s were t o the n e a r e s t 100 meter category. The f r e q u e n c i e s of these s i g h t i n g d i s t a n c e s had the approximate h a l f normal d i s t r i b u t i o n s expected of these c a t e g o r i e s . , The f e a t u r e s of the f r e q u e n c i e s i n F i g u r e 1 t h a t d i s t i n g u i s h e d them as h a l f normal d i s t r i b u t i o n s of these c a t e g o r i e s , r a t h e r than as d i s t r i b u t i o n s of other models of v i s i b i l i t y , was t h e i r i n i t i a l low value, f o l l o w e d by a peak and i n f l e c t e d t a i l . The i n i t i a l low values are a consequence of the f i r s t c a t e g o r y c o v e r i n g only h a l f the a r e a of subsequent c a t e g o r i e s (0-50 m as opposed to 50-150 m, 150-250 m, and so on)- T h i s f e a t u r e was accentuated i n wildebeest because 53% of the s i g h t i n g s were of s o l i t a r y males t h a t tended to p o s i t i o n t h e i r t e r r i t o r i e s away from the t r a n s e c t . The peaks i n the d i s t r i b u t i o n s of Figure 1 r e f l e c t s the f a c t t h at near the t r a n s e c t ( w i t h i n 100 m f o r impala and w i t h i n 300 m f o r wildebeest) almost a l l animals are seen. At t h i s d i s t a n c e , a group's l o c a t i o n i s scanned s e v e r a l times d u r i n g a t r a n s e c t , and the animals tend to flush.; 131 The t a i l s i n the d i s t r i b u t i o n s of F i g u r e 1 r e f l e c t the f a c t t h a t t h e . g r e a t e r the d i s t a n c e from the t r a n s e c t the more v e g e t a t i o n and other topographic f e a t u r e s o b s t r u c t the v i s i b i l i t y of the animals t o the o b s e r v e r s . P l o t t e d on normal p r o b a b i l i t y paper, the cumulative f r e q u e n c i e s of the d i s t r i b u t i o n s i n Fig u r e 1 approximate s t r a i g h t l i n e s when t h e i r zero category values are doubled. The area under a normal d i s t r i b u t i o n of s i g h t i n g d i s t a n c e s i s the d i s t a n c e from both s i d e s of the t r a n s e c t a t which a group i s expected t o be s i g h t e d . That i s , the e f f e c t i v e width of the t r a n s e c t - i , T h e r e f o r e , the area covered d u r i n g a t r a n s e c t (A) i s (Hemingway 1973): A = 3. 14zL Where L i s the t r a n s e c t l e n g t h , and Z i s the average s i g h t i n g d i s t a n c e . In a study with a known d e n s i t y of inanimate o b j e c t s and animals i n a h a b i t a t s i m i l a r t o t h i s study, the c a l c u l a t i o n of the e f f e c t i v e area of the t r a n s e c t s was (Leopold's formulae reworked t o f i t the r e s u l t s ; B o b i n e t t e e t a l 1974): A=3zL A working approach t o the c a l c u l a t i o n of 95% c o n f i d e n c e l i m i t s (x) f o r a t r a n s e c t with a standard d e v i a t i o n of r i g h t -angle s i g h t i n g d i s t a n c e s ( s ) , and a sample s i z e (n) of 30 or more s i g h t i n g s i s (Eberhardt 1978b); x • 2 S/(n) V 2 132 ( f o r sample s i z e s s m a l l e r than 30 the values f o r Student'.s t -d i s t r i b u t i o n , r a t h e r than 2, should be used). These con f i d e n c e l i m i t s are not an i n d i c a t i o n of the r e l i a b i l i t y of a p o p u l a t i o n e s t i m a t e . They are onl y an i n d i c a t i o n of the p r e c i s i o n of the t r a n s e c t r e s u l t s , and as such, the r e l i a b i l i t y of the t r a n s e c t as an index of p o p u l a t i o n change. The accuracy of a p o p u l a t i o n estimate depends on the accuracy o f the d i s t a n c e e s t i m a t i o n s , on t h e accuracy o f the mapping of the p o p u l a t i o n d i s t r i b u t i o n , and of how r e p r e s e n t a t i v e the t r a n s e c t i s of the p o p u l a t i o n ' s d i s t r i b u t i o n . G i l b e r t (1973:97). s t a t e s t h a t : "At present, no p o p u l a t i o n e s t i m a t e s can be taken very s e r i o u s l y , u n l e s s two or t h r e e independent methods o f e s t i m a t i o n g i v e s i m i l a r answers." For most p r a c t i c a l purposes, the predetermination o f the sample s i z e f o r a t r a n s e c t of a p o p u l a t i o n with a known or presumed v a r i a n c e i s (Eberhardt 1978b:230): n = 4 C V p * Where C i s the known or presumed c o e f f i c i e n t of v a r i a t i o n of the r i g h t angle s i g h t i n g d i s t a n c e s (73% f o r wildebeest and 99% f o r impala; T a b l e 1), and p i s the p r e c i s i o n r e q u i r e d i . e . t h e d e v i a t i o n s of the 95% c o n f i d e n c e l i m i t s from the mean expressed as a p r o p o r t i o n o f the mean. T h i s p r e c i s i o n averaged 27% and 35% f o r t r a n s e c t s t h a t 'averaged 29 and 32 s i g h t i n g s of wildebeest and impala r e s p e c t i v e l y . 133 L i t e r a t u r e c i t e d : Caughley,G.1977- A n a l y s i s of V e r t e b r a t e P o p u l a t i o n s . Wiley and Sons, Toronto. Eberhardt,L-L.1968- A p r e l i m i n a r y a p p r a i s a l of l i n e t r a n s e c t s . J . W i l d l . Manage. 32:323-342. — — .1978a. Transect methods f o r p o p u l a t i o n s t u d i e s . J . W i l d l . Manage. 4 2:1-31. • .1978b. A p p r a i s i n g v a r i a b i l i t y i n p o p u l a t i o n s t u d i e s . J . W i l d l . Manage. 42:207-238. Gainer, R.S. 1979- Anthrax and Wildebeest. M.Sc. T h e s i s . U n i v e r s i t y of B r i t i s h Columbia, Vancouver, B.C., Canada. Gilbert,N-1973- B i o m e t r i c a l I n t e r p r e t a t i o n - Clarendon P r e s s , Oxford- . Hemingway,P.1971- F i e l d t r i a l s of the l i n e t r a n s e c t method of sampling p o p u l a t i o n s of l a r g e h e r b i v o r e s , i n : The S c i e n t i f i c Management of Animal and P l a n t Communities f o r Conservation- ed by E.Duffey and A.Watt:405-411-m 1973- The importance of v i s i b i l i t y i n p o p u l a t i o n d e t e r m i n a t i o n . Paper presented t o the S e r e n g e t i Symposium on P o p u l a t i o n R e g u l a t i o n i n T r o p i c a l V e r t e b r a t e s , Hirst,S.M.1969. R o a d - s t r i p census f o r w i l d ungulates i n A f r i c a n woodland. J . W i l d l . Manage. 33:40-48. Kovener, J.L., P- Hemingway and S.A. P a t i l . Pers- comm. L i n e t r a n s e c t sampling of grouped w i l d l i f e with t e s t a b l e hypotheses f o r group s i z e and s i g h t i n g d i s t a n c e , Robiaette,W.L., C.W.Loveless and D.A.Jones. 1974. F i e l d t e s t s of s t r i p census methods. J.Wildl.Manage.38:81-96. Sokal,R.R. and F.J.Rohlf.1973. I n t r o d u c t i o n to B i o m e t r i c s . Freeman and Co.,San F r a n c i s c o . , 1 3 4 APPENDIX VI. A SDSVEY OF THE PARASITES. DISEASES. AND ANOMALIES IN ANIMALS OF THE SELOUS; AND THEIR MANAGEMENT CONSIDERATIONS I n t r o d u c t i o n Those who have p r e v i o u s l y surveyed the p a r a s i t e s and d i s e a s e s of A f r i c a n wild animal p o p u l a t i o n s have r a r e l y c o n s i d e r e d the s i g n i f i c a n c e of these p a r a s i t e s and d i s e a s e s f o r t h e management of animal p o p u l a t i o n s ; r a t h e r , they have c o n f i n e d themselves to t h e i r e p i z o o t i o l o g i c a l s i g n i f i c a n c e . Because o f t h i s , few managers of w i l d animal p o p u l a t i o n s i n A f r i c a n , and f o r t h a t matter i n any Other p a r t s o f the world, know what p a r a s i t e s and d i s e a s e s are s i g n i f i c a n t t o the p o p u l a t i o n s which they manage. T h i s r e p o r t attempts t o r e c t i f y t h i s s i t u a t i o n . In the f i r s t p a r t , I present the r e s u l t s of my survey and c o n s i d e r the e p i z o o t i o l o g i c a l i m p l i c a t i o n s of the survey's being made i n an i s o l a t e d p a r t o f the world..In the second p a r t , I c o n s i d e r the i m p l i c a t i o n s of my r e s u l t s f o r management of w i l d animal p o p u l a t i o n s . The wild animal p o p u l a t i o n s which have been surveyed i n o t h e r s t u d i e s have had c l o s e e p i z o o t i o l o g i c a l c o n t a c t s with domestic ungulates o f A f r i c a n o r i g i n . That i s , they have had an a s s o c i a t i o n which permitted the t r a n s m i s s i o n of p a r a s i t e s and/or d i s e a s e s between them. In a d d i t i o n , many of these domestic ungulates of A f r i c a n o r i g i n have had e p i z o o t i o l o g i c a l c o n t a c t with domestic ungulates of European o r i g i n . 135 N e i t h e r of these s i t u a t i o n s e x i s t e d i n the area where I have done my study, i . e . i n the Selous Game Reserve. The Selous Game Reserve i s an enormous r e g i o n (55,000 sg km), which has been without human p o p u l a t i o n s i n c e 1952. P r i o r to t h i s , human se t t l e m e n t was minimal and without domestic ungulate husbandry. In a d d i t i o n , there i s an even l a r g e r area of l a n d surrounding the re s e r v e — e s s e n t i a l l y the whole southeast c o r n e r of Tanzania — which i s only s p a r s e l y s e t t l e d . I t i s p r i m a r i l y because of the presence o f t s e t s e f l i e s , which t r a n s m i t trypanosomiasis (nagana) from w i l d ungulates to domestic ungulates, t h a t t h i s r e g i o n does not have a h i s t o r y of domestic animal husbandry. And human s e t t l e m e n t s are without dogs because of the abundance of l e o p a r d s . With the e x c e p t i o n of t h r e e s i t u a t i o n s , t h e r e have never been any domestic ungulates w i t h i n a 200 km r a d i u s (by a i r ) of the study area. The f i r s t e x c e p t i o n i s durin g the l a t e 1940's when a b r i e f l i v e s t o c k , d r i v e was made from Hahenge to the groundnut scheme atNachingewa. T h i s d r i v e passed w i t h i n 100 km (by a i r ) to the south of the study area (B.D. Ni c h o l s o n pers. comm.). The second e x c e p t i o n i s the r e c e n t government attempt to r a i s e l i v e s t o c k at the ujamaa v i l l a g e o f Lihenga, 30 km e a s t of the study a r e a . E l e v e n c a t t l e were i n t r o d u c e d i n 1970; e i g h t o f which were s t i l l a l i v e i n 1973. Because the area has an abundance of wi l d c a r n i v o r e s , these animals were s t r i c t l y c o n f i n e d t o the v i l l a g e l i m i t s . 136 The t h i r d e x c e p t i o n i s the i m p o r t a t i o n of domestic goats i n t o the few v i l l a g e s o u t s i d e the r e s e r v e . Because these animals were f o r r e l i g i o u s c e l e b r a t i o n s t h e i r presence, although frequent, was b r i e f . In a d d i t i o n , most of these v i l l a g e s are more than 50 km from the r e s e r v e . Because of my very g e n e r a l treatment i n t h i s survey of the e p i z o o t i o l o g y of each p a r a s i t e , the s p e c i f i c i d e n t i f i c a t i o n of most p a r a s i t e s i s not important and* f o r t h i s reason, I have not presented a l l the p a r a s i t e i d e n t i f i c a t i o n s performed. However, Dr. B- Sachs ( T r o p e n i n s t i t u t , 2000 Hamburg 4, Bernhard-Nocht-Strabe 74, W. Germany) has performed e x t e n s i v e i d e n t i f i c a t i o n s i n c o n j u n c t i o n with Dr. Dinnik (Paramphistomidae and T a e n i a ) , Dr. Shoho ( F i l a r o i d i d a e ) , Drs. Back and van H a f f n e r {Pentastomida) # Dr. Hoogstraal (Ixodidae), Dr. Wetzel ( O e s t r i d a e ) , and Dr. K h a l i l and Mrs. Lweno (Nematoda). M a t e r i a l s and Methods The presence of p a r a s i t e s , d i s e a s e s , and anomalies was d e t e c t e d i n t h r e e ways: (1) by a f i e l d search f o r dead or dying animals; (2) by the post mortem examination of h e a l t h y r e p r e s e n t a t i v e s of the p o p u l a t i o n ; and (3) by the c o l l e c t i o n of serum and f e c a l samples f o r l a b o r a t o r y a n a l y s i s . The f i e l d search f o r dead or dying animals was part o f many other d u t i e s , i n c l u d i n g the census of animal p o p u l a t i o n s , the hunting of animals f o r post mortem examinations, and the performance of s e v e r a l management f u n c t i o n s . I f a weak animal 137 was encountered, evey e f f o r t was made to c o l l e c t i t f o r a post mortem examination., Post mortems were performed i n accordance with the b a s i c methods of Cowan and Karstad (1969). They were not performed on the dead animals we encountered because of the hazard of anthrax. But the date of d i s c o v e r y and the l o c a t i o n of the c a r c a s s , along with the sex and age c l a s s , were r o u t i n e l y noted. With the blood o r t i s s u e f l u i d s from s e v e r a l of these c a r c a s s e s , we prepared s t a i n e d s l i d e s , and soaked swabs and f i l t e r paper f o r submission t o the C e n t r a l V e t e r i n a r y L a b o r a t o r y ' s b a c t e r i o l o g y department. In a d d i t i o n , we i n j e c t e d mice with c a r c a s s f l u i d s (Appendix I) . We c o l l e c t e d h e a lthy r e p r e s e n t a t i v e s of the animal p o p u l a t i o n s f o r post mortem examination by shooting randomly s e l e c t e d y e a r l i n g s and o l d e r animals. D i s s e c t i o n of the c a r c a s s was performed as d e s c r i b e d by Cowan and K a r s t a d (1969). T h i s i n c l u d e d a removal and examination of the b r a i n , u t i l i z i n g a "panga". In our examination and c o l l e c t i o n of p a r a s i t e s , and i n the r e c o r d i n g of i n f o r m a t i o n , we e v e n t u a l l y took over the procedures p r e s c r i b e d by Sachs and Debbie (1969). Because p a r a s i t e s have been d i s c o v e r e d s i n c e the p u b l i c a t i o n of t h i s a r t i c l e , Dr. Sachs m o d i f i e d and expanded our technique i n many ways. These changes are o u t l i n e d a l o n g with the r e s u l t s of the p a r t i c u l a r p a r a s i t e . In a d d i t i o n , we examined the d i s t r i b u t i o n and abundance o f "measle c y s t s " , the f i r m , white, pea-sized l a r v a e of Taenia spp. tapeworms t h a t e n c y s t i n the f l e s h of most ungulate s p e c i e s and which are of g r e a t concern i n the i n s p e c t i o n o f meat. We d i d 138 t h i s by d i v i d i n g a c a r c a s s i n t o s e v e r a l d i f f e r e n t r e g i o n s , removing the f l e s h from these r e g i o n s , weighing i t , s l i c i n g i t i n t o t h i n s e c t i o n s , and examining i t f o r measles. The animals c o l l e c t e d f o r the post mortem examination were u s u a l l y shot i n the neck t o f a c i l i t a t e our c o l l e c t i n g one l i t e r of blood from the j u g u l a r v e i n . The serum of wildebeest and l a r g e r a n t e l o p e was c o l l e c t e d by a l l o w i n g t h e i r blood to s e t t l e f o r s e v e r a l hours; while the serum of s m a l l e r animals was c o l l e c t e d by c e n t r i f u g a t i o n . The serum was then f r o z e n u n t i l , and d u r i n g , i t s t r a n s p o r t t o Dr. P. Hummel a t the C e n t r a l V e t e r i n a r y L a b o r a t o r y and Dr. J . Thorsen i n N a i r o b i , who d i s t r i b u t e d i t to the v a r i o u s d i v i s i o n s w i t h i n the East A f r i c a n V e t e r i n a r y Research O r g a n i z a t i o n and Rabate V e t e r i n a r y L a b o r a t o r i e s . In a d d i t i o n t o c o l l e c t i n g blood, while i t was s t i l l f l o w i n g we prepared two t h i c k and two t h i n blood smears. These were d r i e d , f i x e d i n methanol, and submitted t o Dr. C e n t u r i e r a t the C e n t r a l V e t e r i n a r y Laboratory f o r b l o o d p a r a s i t e examination. I n accordance with the methods of Sachs and Sachs (1968), we c o l l e c t e d samples o f f r e s h f e c e s from wildebeest, impala, and b u f f a l o herds on which we d i d McMaster f e c a l counts (Benbrook and S l o s s 1965). Each sample was wrapped i n p l a s t i c and ce l l o p h a n e tape, s t o r e d i n a r e f r i g e r a t e d but unfrozen c o n d i t i o n , and submitted t o Dr. Sachs and the s t a f f of the C e n t r a l V e t e r i n a r y L a b o r a t o r y ' s p a r a s i t o l o g y department. Specimen m a t e r i a l f o r b a c t e r i o l o g i c a l c u l t u r e was p l a c e d i n a s e p t i c c o n t a i n e r s , s t o r e d i n a r e f r i g e r a t e d but unfrozen c o n d i t i o n , and submitted to Dr. Hummel of t h e C e n t r a l V e t e r i n a r y 139 L a b o r a t o r y ' s b a c t e r i o l o g y department. T i s s u e c o l l e c t e d f o r h i s t o p a t h o l o g i c a l examination was pla c e d i n 10% f o r m a l i n and submitted t o Dr. H. Jakob and Mr. E-Gorton o f the C e n t r a l V e t e r i n a r y L a b o r a t o r y ' s pathology department. P a r a s i t e s t h a t were c o l l e c t e d f o r i d e n t i f i c a t i o n s were s t o r e d i n e i t h e r 4% f o r m a l i n o r 70%. .• a l c o h o l s These were submitted t o Dr. Sachs. The e x t e n s i v e survey of p a r a s i t e s and d i s e a s e s o f A f r i c a n w i l d animal s p e c i e s by Dr. M.H. Mustafa, i n p a r t i a l f u l f i l l m e n t o f h i s diploma requirements a t the A f r i c a n C o l l e g e of W i l d l i f e Management (Mustafa 1973) was used throughout the p r e p a r a t i o n o f t h i s manuscript, d e s p i t e the f a c t I make l i t t l e r e f e r e n c e to i t . R e s u l t s The f o l l o w i n g l i s t of animals were wholly . or p a r t i a l l y examined i n the manner d e s c r i b e d above; 121 wildebeest,, 105 impala, 38 h a r t e b e e s t , 18 warthog, 9 z e b r a , 6 b u f f a l o , 5 e l a n d , 5 s a b l e , 5 l i o n , 4 l e o p a r d , 3 bushpig, 3 w i l d dog, 1 waterbuck, and 1 hyena. P a r a s i t e s P a r a s i t e s a re arranged i n phyla a c c o r d i n g t o Soulsby (1968). The prevalence and l e v e l of the more common groups i s given i n Table 1. Table 1. The r e s u l t s of the post mortem examinations of randomly s e l e c t e d , o s t e n s i b l y normal members of Selous Game Reserve ungulate populations, 1971 - 1973. Only the more f r e q u e n t l y encountered p a r a s i t e groups are presented. (Prev. = prevalence, LOI = average number of p a r a s i t e s found.) Wildebeest Prev. LOI Impala Hartebeest Prev. LOI Prev. LOI Warthog Prev. LOI Buf f a l o Eland Prev. LOI Prev. LOI Ticks Pentastamid larvae ( L i n g u a t u l i d type) 120/121 12.4 51/65 4.0 25/30 13.9 14/16 13.0 6/6 115.0 5/5 85.0 16/22 6.4 3/33 0.2 6/18 1.5 0/11 6/6 46.0 1/5 0.2 Paramphis.tomi dae 9/91 11/52 11/35 6/15 5/6 4/5 Muscle c y s t i c e r c i Serosal c y s t i c e r c i 35/37 26.0 18/28 3.9 12/17 7.6 2/11 3.2 4/6 33/53 1.6 6/47 0.2 8/18 1.2 3/11 1.5 0/6 1.3 3/5 15.6 0/5 Sacral c y s t i c e r c i i 29/53 Hydatid cysts 2/113 Moniezia spp. 10/89 0.9 0/18 0/105 7/67 16/18 0/35 4/18 4.0 0/2 6/10 0/4 0/6 2/6 0/4 0/5 4/5 P r o t o s t r o n g l i dae ( l e v e l of i n f e c t i o n i n grams per l e s i o n ) 46/90 4.5 82/97 22.3 26/37 12.3 0/18 0/6 0/5 Cont'd.. Table 1 Cont'd. WiTdebeest Impala Hartebeest Warthog B u f f a l o Eland Prev. LOI Prev. LOI Prev. LOI Prev. LOI Prev. LOI Prev. LOI Setaria spp. 45/87 1.6 1/59 0.02 10/18 2.2 5/14 2.1. 1/6 5.8 5/5 9.0 Abomasum nematodes (stomach-warthog) 35/47 8/83 7/17 7/15 4/6 5/5 Ancy.iostomidae 11/61 0/67 9/17 0/6 0/5 Oestridae 75/75 42.0 0/24 21/21 68.0 0/4 0/4 0/4 1 4 2 Arthropoda: Although we d i d not conduct a survey o f the area's i n s e c t s , we were plagued by sucking i n s e c t s i n c l u d i n g t s e t s e f l i e s ( G l o s s i n a spp.) and mosguitos ( C u l i c i d a e ) , and a m y i a s i s caused by chrysops f l y (Chrvsops spp.) l a r v a e . Geigy et a l . (1967) have i d e n t i f i e d s e v e r a l z o o p h i l i c G l o s s i n a moristans i n the western r e g i o n of the r e s e r v e . A complete i n s e c t survey would be extremely v a l u a b l e . Not only would i t p r o v i d e i n f o r m a t i o n on the arthopod p a r a s i t e s , but the knowledge of the v e c t o r s p e c i e s would suggest the presence or absence of s e v e r a l d i s e a s e s . T i c k s (Ixodidae) were recovered from every animal s p e c i e s we examined, and l i o n f l i e s (Hippoboscidae) were recovered from impala, e l a n d , b u f f a l o , and h a r t e b e e s t . T i c k i d e n t i f i c a t i o n s are given i n Table 2. Had we used s p e c i f i c c o l l e c t i o n techniques, we probably would have c o l l e c t e d l a r g e r g u a n t i t i e s and a g r e a t e r v a r i e t y of e x t e r n a l p a r a s i t e s . As i t was, we d i d not f i n d any g r o s s cutaneous l e s i o n s such as a l o p e c i a , p s o r i a s i s , and seborrhea which are a s s o c i a t e d with heavy e x t e r n a l p a r a s i t e i n f e s t a t i o n s , we d i d f i n d t h a t b u f f a l o and e l a n d were p a r t i c u l a r y h e a v i l y i n f e s t e d , and impala p a r t i c u l a r l y l i g h t l y i n f e s t e d with a d u l t t i c k s (Table 1). He c o l l e c t e d l a r v a e o f bot f l i e s (Oestridae) from the n a s a l s i n u s e s of every wildebeest and h a r t e b e e s t t h a t we examined (Table 1).. T h e i r i d e n t i f i c a t i o n s are given i n Table 3. They are a l s o a common i n f e c t i o n of antelope of the s u b - f a m i l y A l c e l a p h i n a e (Bindernagel 1968, Sachs 1970, Basson e t a l . 1970, Mustafa 1973, Howard 1977). 143 T a b l e 2. The t i c k s p e c i e s i d e n t i f i e d f r o m u n g u l a t e s p e c i e s o f t h e S e l o u s Game R e s e r v e , 1971 - 1973 ( C M . C l i f f o r d ; a n d J . E . K e i r a n s p e r s . c o m m . ) . I m p a l a H a r t e b e e s t W i l d e b e e s t S a b l e W a r t h o g Z e b r a E l a n d B u f f a l o Rhipicepha-lus evertsi R. appendiculatus R. simus R. longus R. maculatus Amblyoma vai'iegatum A. gemma Hyalomrna tvuncatwn Boophilus decoloratus T a b l e 3 . The s p e c i e s o f b o t f l y l a r v a e {Oestridae) i n u n g u l a t e s o f t h e S e l o u s Game R e s e r v e , 1971 - 1973 ( H . W e t z e l p e r s . comm. W i l d e b e e s t H a r t e b e e s t Z e b r a Oestrus maodonaldi . X 0. aureoargentatus X X 0. variolosus X X Kirkioestrus blanahardi X K. minutus X Gedoelstia haessler-i X X G. oristata X X. Gasterophilus nasalis X G. intestinalis X G. ternicuictus X 145 In a d d i t i o n , minute o e s t r i d l a r v a e o f G e d o e l s t i a h a e s s e l e r i were found on the b r a i n s u r f a c e of 11 o f 14 wildebeest, but not on the b r a i n s u r f a c e of 14 impala, 11 h a r t e b e e s t , 4 b u f f a l o , 4 e l a n d , 4 warthog, 3 bushpig, and 2 zebra. T h i s p a r a s i t e commonly i n f e c t s t h e b r a i n s u r f a c e of wildebeest and zebra (Sachs 1970, Basson e t a l . 1971). Inflammation, c a t a r r a h , and mild hemorrhage i n 5% of the f r o n t a l s i n u s e s of the wildebeest and h a r t e b e e s t were the only p a t h o l o g i c a l symptoms a s s o c i a t e d with O e s t r i d a e i n f e c t i o n s . We encountered G a s t r o p h i l u s spp. bot f l y l a r v a e , a common zebra i n f e c t i o n (Orguhart e t a l . 1960), i n the stomachs of seven of e i g h t zebra. But warbles (Hypoderma spp.). o f t e n encountered d u r i n g the s k i n n i n g of A f r i c a n a n t e l o p e s (Orguhart e t a l . 1960, Zumpt 1965, Sachs and Sachs 1968), were never encountered durng our s k i n n i n g of 250 a n t e l o p e . We commonly recovered pentastomid l a r v a e of the L i n q u a t u l a m n l t i a n n u l a t a o r N e o l i n q u a t u l a n u t t a l l i type from the bovidae s p e c i e s which we examined (Table 1). In most s p e c i e s , the b r o n c h i a l lymph nodes were the most h e a v i l y i n f e c t e d organ, but i n b u f f a l o the mesenteric lymph nodes, l i v e r , and h e a r t (inner v e n t r i c u l a r surface) were most h e a v i l y i n f e c t e d . B u f f a l o were by f a r the most h e a v i l y i n f e c t e d s p e c i e s , impala and e l a n d the l e a s t i n f e c t e d ( F i g . 1). Eleven warthogs, 3 bushpigs, and 2 zebra were not found to be i n f e c t e d . These l a r v a e commonly i n f e c t A f r i c a n as w e l l as other bovidae (flaffner et a l . 1967, Sweatman 1971, Sachs e t a l . 1973a, Young 1975). 146 Pig.ure 1, The average number o f pentastomid l a r v a e of the l i n g u a t u l i d type c o l l e c t e d from each animal a c c o r d i n g to host s p e c i e s i n the Selous Game Beserve 1971-1973. Pi g u r e 2. The average number of muscle c y s t i c e r c i per ki l o g r a m of body weight, a c c o r d i n g to host s p e c i e s , i n the Selous Game Beserve 1971^1973.. F i g u r e 3- The average number o f muscle c y s t i c e r c i per k i l o g r a m of f l e s h from the r e g i o n s i n which they were l o c a t e d (Table 7 and Table 8) a l l host s p e c i e s combined, i n the Selous Game Beserve, 1971-1973-. Frequency O Hind leg Front leg F i l l e t Masseter Heart Tongue Chest Neck Li ver Hip Diaphragm Brain Lung • • • O P U) Average Numbers O B u f f a l o Wi 1debeest Hartebeest Impala Eland Harthog CD O a \1 ) I 31 CD Number/Kilo o Wi1debeest Impala Warthog Hartebeest Eland B u f f a l o CD O J L ] ] § • I (V) Lrjl 148 An average of three a d u l t pentastomids, N e o l i n q u a t u l a n u t t a l l i , were c o l l e c t e d from the n a s a l s c r o l l s of two of f i v e l i o n s , and th r e e a d u l t L i n q u a t u l a m u l t i a n n u l a t a were c o l l e c t e d from the one hyaena. These are t y p i c a l s p e c i e s s p e c i f i c i n f e c t i o n s f o r these hosts (Sachs e t a l . 1973).,The t h r e e w i l d dogs were not i n f e c t e d with a d u l t pentastomids. D e t a i l s of these i n f e c t i o n s are given i n Sachs e t a l . (1973a). He encountered pentastomid l a r v a e o f the A r m i l l i f e r a r m i l l a t u s type i n one ha r t e b e e s t , one l e o p a r d , and one guinea-fowl (Numida m i t r a t a ) . Every organ, but e s p e c i a l l y the se r o s a , o f the h a r t e b e e s t and l e o p a r d were i n f e c t e d . The female h a r t e b e e s t was mature, but her s i z e was s m a l l and her r e p r o d u c t i v e t r a c t was i n a c t i v e , s u g g e s t i n g t h a t her growth had been impaired by t h i s I n f e c t i o n . The l e o p a r d , however, was normal* A r m i l l i f e r a r m i l l a t u s l a r v a e commonly cause d e b i l l a t i n g i n f e c t i o n s , i n v i r t u a l l y a l l s p e c i e s o f mammals (SWeatman 1971, Young 1:975a) w .The a d u l t l i v e s i n the r e s p i r a t o r y t r a c t of snakes such as Python sebae. a snake common to t h i s r e g i o n . Protozoa: Anaplasma marginale were seen i n the blood smears from wildebeest and h a r t e b e e s t ; and T h e i l e r i a s p p . - l i k e organisms were seen i n b l o o d smears from s a b l e . They are a l s o commonly found i n blood smears from a n t e l o p e s (Drevemo e t a l . 1974, Carmichael and Hobday 1975). Trypanosoma b r u c e i and T. conqolense were d e t e c t e d i n •, blood smears from l a b o r a t o r y mice which had been i n j e c t e d with blood from s e v e r a l ungulate s p e c i e s from the western r e g i o n of the rese r v e (Geigy et a l . 1967)., He d i d not make t h i s e f f o r t to d e t e c t trypanosomes, but t h e r e was every i n d i c a t i o n t h a t the 8 1 4 9 c a t t l e remaining a t Lihenga s u f f e r e d s e v e r e l y from t h i s i n f e c t i o n . A l s o , p r i o r to 1952, the set t l e m e n t s i n the r e s e r v e had severe human s l e e p i n g s i c k n e s s problems (Hatzke 1975). The Miescher*s tubes of s a r c o s p o r i d i a were commonly encountered i n a l l ungulate s p e c i e s . In b u f f a l o , e l a n d , and warthog they were c l e a r l y v i s i b l e m a c r o s c o p i c a l l y , e s p e c i a l l y i n the esophagus and muscles of the neck r e g i o n . In impala, w i l d e b e e s t , and hartebeest,. t h e i r presence was d e t e c t e d m i c r o s c o p i c a l l y i n s t a i n e d s e c t i o n s of myocardium. S a r c o s p o r i d i a a r e a l s o common antelope i n f e c t i o n s (Sachs and Sachs 1968, K a l i n e r e t a l . 1971, 1974, Basson e t a l . 1971). C o c c i d i a l o o c y s t s were commonly encountered dur i n g the McMaster count of impala f e c e s , although no l e s i o n s were r e c o g n i z e d d u r i n g the examination of s e v e r a l impala i n t e s t i n e s . The f e c e s o f impala i n o t h e r s t u d i e s have o f t e n c o n t a i n e d these o o c y s t s (Sachs and Sachs 1968, Basson e t a l , 1971, Fay 1972). B e s n o i t i o s i s , a common i n f e c t i o n i n South A f r i c a n w i l d e b e e s t and impala (Basson e t a l . 1971), was not dete c t e d d u r i n g our r o u t i n e examination of the he a r t and a o r t a . T h i s i n f e c t i o n i s more e a s l y r e c o g n i z e d on the endothelium .of the j u g u l a r and ot h e r p e r i p h e r a l veins., K l o s s i e l o s i s , a common i n f e c t i o n o f South A f r i c a n zebra (Basson e t a l . 1971), was not found d u r i n g s p e c i f i c h i s t o p a t h o l o g i c a l examinations f o r t h i s organism i n three zebra kidneys. Trematoda; Paramphistomidae commonly i n f e c t ungulates; Paramphistomum spp* i n f e c t ruminant s p e c i e s and G a s t r o d i s c u s a e q y p t i a c u s i n f e c t caeca of warthogs, bushpig, and zebra (Dinnik 150 e t a l . 1963, Bound 1968, Sachs and Sachs 1968). In t h i s study, we c o l l e c t e d Paramphistomum spp. from evey ruminant s p e c i e s we examined, i n c l u d i n g wildebeest, impala, h a r t e b e e s t , b u f f a l o , eland and s a b l e , and we c o l l e c t e d G a s t r o d i s c u s a e g y p t i a c u s from warthogs and zebra (Table 1).. F a s c i o l i a s i s i s a common i n f e c t i o n o f wi l d and domestic ungulates i n A f r i c a (Sachs and Sachs 1968, Round 1968, Woodford 1972, Fay 1972, Hammond 1972). Every l i v e r i n t h i s study was c a r e f u l l y s l i c e d , and examined f o r f l u k e s . In a d d i t i o n , p o r t i o n s of the l i v e r s from 10 wildebeest, 10 impala, 5 ha r t e b e e s t , 2 b u f f a l o , and 2 eland were macerated and then soaked i n warm s a l i n e o v e r n i g h t . However, no l i v e r f l u k e s were found. S c h i s t o s o m i a s i s ( b i l h a r z i a s i s ) i s a common i n f e c t i o n o f w i l d and domestic ungulates i n South A f r i c a (Basson e t a l . 1971, P i t c h o r d e t a l . i n prep.) of domestic ungulates and, to a l e s s e r e x t e n t , o f w i l d ungulates i n E a s t A f r i c a (Dinnik and Dinnik 1965). We c l o s e l y examined, m a c r o s c o p i c a l l y , the mesenteric v a s c u l a t u r e of almost every animal autopsied i n t h i s study, but we d i d not d e t e c t the presence o f t h i s p a r a s i t e . Baboon (Papio cynocephalus) and hippo, two s p e c i e s which are more l i k e l y to harbour t h i s i n f e c t i o n , were not examined. . Uematoda: P r o t o s t r o n g y l i d a e commonly, i n f e c t and cause the c o n s o l i d a t i o n of antelope lungs (Dinnk and Sachs i?68, Sachs and Sachs 1968, Fay 1972). In t h i s study, we only encountered s m a l l P r o t o s t r o n g y l i d a e {Pnenmonstrongylus spp.), i n wildebeest, h a r t e b e e s t , and impala. Impala were the most h e a v i l y i n f e c t e d (Table 1). Although every lung was thoroughly examined, we never detected the presence of D i c t y o c a u l u s spp. which are lungworms 151 t h a t i n f e c t a n t e l o p e s i n other r e g i o n s (Bound 1968, Dinnik and Sachs 1968, Sachs and Sachs 1968, Bi n d e r n a g e l 1968, Fay 1972). C o o p e r i o i d e s h e p a t i c a e (Cooperia he pa t i c a) i s a common i n f e c t i o n of impala l i v e r s (Sachs and Sachs 1968, Bound 1968, Fay 1972). In t h i s study, we found t h i s p a r a s i t e to i n f e c t most of the l i v e r s of impala, hut we d i d not f i n d i t i n any oth e r s p e c i e s . Sometimes the i n f e c t i o n s were a s s o c i a t e d with l a r g e r e g i o n s o f l i v e r f i b r o s i s and c a l c i f i c a t i o n . D e l a f o n d i a v u l g a r i s i s a common i n f e c t i o n o f the l i v e r s o f zebra i n south A f r i c a (McCully e t a l . 1969, Basson e t a l . 1971), and S t r o n g y l u s a s i n i i s a common i n f e c t i o n of the l i v ers of zebra i n East A f r i c a (Urguhart e t a l . 1960, Bound 1968). He recovered from most of the zebra l i v e r s a s p e c i e s o f S t r o n g y l i d a e which f i t the d e s c r i p t i o n of both of the above s p e c i e s . T r i c h i n e l l a s p i r a l i s i s a common i n f e c t i o n of A f r i c a n c a r n i v o r e s and scavengers (Sachs 1975). A s e c t i o n of diaphragmatic p i l l a r from the one hyaena was h e a v i l y i n f e c t e d , but s e c t i o n s from the diaphragmatic p i l l a r s of 10 warthogs and 3 bushpigs were not. Other f r e g u e n t l y i n f e c t e d s p e c i e s such as l i o n and j a c k a l (Canis aureus). were not examined. S e t a r i i d a e a re commonly found i n the p e r i t o n e a l c a v i t i e s o f ungulates (Bound 1968)... The i d e n t i f i c a t i o n s and hosts of the s p e c i e s c o l l e c t e d i n t h i s study are given i n Table 4. Onchocercinae a r e common i n f e c t i o n s o f ruminants (Sachs and Sachs 1968, Bound 1968, Basson e t a l . ^ 1971)*; He recovered Onchocerca spp./from impala and h a r t e b e e s t , but net from wildebeest, h a r t e b e e s t , b u f f a l o , and eland. T h e i r g r e a t e s t 152 Table 4 . The Setaria spp. from the abdominal c a v i t i e s of ungulates i n the Selous Game Reserve, 1971-1973 (R. Sachs, pers. comm.) -S. poultoni S. hornbvi S. equina S. bicoronata S. c a s t r o i S. nelsoni Wildebeest, hartebeest Sable Zebra Hartebeest Saterbuck Buffalo S. a f r i c a n a Eland 153 numbers were found on the i n n e r s u r f a c e of the cutaneous f l a n k m u s c l e — the t h i n muscle u s u a l l y l e f t attached t o the h i d e when the hide i s h a s t i l y removed. We examined every h e a r t , but n e i t h e r C o r d o p h i l u s nor Elaeophora spp*, p a r a s i t e s which i n f e c t the myocardium and a o r t a of a n t e l o p e s (Sachs and Debbie 1969, Basson e t a l . 1971), was found. The eyes of each animal were removed and examined, but T h e l a z i a r h o d e s i i , a common eye i n f e c t i o n of A f r i c a n animals (Dinnik e t a l . 1963, Bound 1968, Bindernagel 1968), was never encountered. N e i t h e r d i d we encounter Gongylonema spp., an i n f e c t i o n of the submucosae of antelope esophagus, d u r i n g our removal and examination of the esophagus o f each of the animals. Synqamus spp. can be found i n the n a s a l s c r o l l s of Kobus spp. antelope (Sachs e t a l . 1 9 6 9 ) . We d i d not f i n d any i n the one waterbuck (the o n l y Kobus sp. examined) , 5 wildebeest, 5 h a r t e b e e s t , 5 impala, 2 b u f f a l o , and 2 eland from which the n a s a l s c r o l l s were removed and soaked o v e r n i g h t i n s a l i n e . T r i c h o s t r o n g y l i d a e commonly i n f e c t the abomasum and s m a l l i n t e s t i n e of ruminants; Bunpstpmum spp. i n f e c t t h e i r s m a l l i n t e s t i n e s , and Agriostomum and Oesophaqostomum spp., t h e i r l a r g e i n t e s t i n e s (Bound 1968). The d i f f e r e n t s p e c i e s o f these Haemonchus are d i s c u s s e d by Sachs e t a l . (1973b). The r e c o r d of the recovery of these p a r a s i t e s from the ungulates i n t h i s study i s g iven i n T a b l e s 1 and 5. In 2 w i l d e b e e s t , the presence of Agriostomum spp. was a s s o c i a t e d with a severe, hemorrhagic and c a t a r r h a l e n t e r i t i s of the s p i r a l c o l o n . T a b l e 5 . N e m a t o d e s f r o m i n t h e g a s t r o - i n t e s t i n a l t r a c t s o f u n g u l a t e s o f t h e S e l o u s Game R e s e r v e , 1 9 7 1 - 1 9 7 3 ( R . S a c h s p e r s . c o m m . ) . Genus W i l d e b e e s t H a r t e b e e s t I m p a l a S a b l e W a t e r b u c k Haemonahus rCooperia Trichostrongylus Longistrongylus Gaigeria Impalaia I Bunostomum Agriostomum Oesophagostomum 1 = abomasum 2 = s m a l l i n t e s t i n e s 3 = l a r q e i n t e s t i n e s 155 In Table 6 I present the number of S t r o n g y l e - t y p e eggs which we found u s i n g the 2Sc Master count i n the f e c e s of w i l d e b e e s t , impala, and b u f f a l o . Compared to s t u d i e s i n which there was a lower predator-prey r a t i o , t h e i r mean values are low. And they are lower than the valu e s found i n an area with a f a i r l y high (prote c t e d predator) predator-prey r a t i o (Table 7 ) . The seasons d u r i n g which the f e c e s were c o l l e c t e d , an important p o i n t , are not c o n s i d e r e d however. , Cestoda: The f l e s h of A f r i c a n ungulates are commonly i n f e c t e d with muscle c y s t i c e r c i ( m e a s l e s ) — f i r m , white, pea-s i z e d c y s t s . Wild ungulates tend to be i n f e c t e d with a s p e c i e s a s s o c i a t e d with the presence o f Taenia gonyamai (a . common l i o n i n f e c t i o n (Dinnik and Sachs 1969a, 1972) i n the reg i o n ' s l i o n s . And domestic ungulates tend t o be i n f e c t e d with a s p e c i e s , C y s t i c e r c i b o v i s , an i n t e r m e d i a t e stage of the human tapeworm, Taenia s a g i n a t a (Nelson e t a l . 1965, Sachs 1969a, Basson e t a l . 1971, Woodford and Sachs 1973). In t h i s study we c o l l e c t e d measle c y s t s from every ungulate s p e c i e s we examined except f o r zebra (Table 1) i . e . from b u f f a l o , e l a n d , wildebeest, h a r t e b e e s t impala, warthog, s a b l e , and bushpig. These c y s t i c e r c i were d i f f e r e n t i a t e d from c y s t i c e r c i o f s a g i n a t a and T. sol i u m , and i d e n t i f i e d as the s p e c i e s normally a s s o c i a t e d with the presence of T. gonyamai i n the area's l i o n s (Sachs 1969a). T h i s i s the f i r s t time, t h a t I know o f , t h a t t h i s s p e c i e s o f c y s t i c e r c i has been re c o v e r e d from warthog and bushpig. Taenia gonyamai was recovered from the i n t e s t i n e s o f two of the f i v e l i o n s . 156 Table 6. The r e s u l t s of the McMaster method of counting strongyle type eggs i n the feces of several animals of the three most abundant ungulate species i n the Selous Game Reserve, 1971 -1973 (R. Sachs and E. Dehne, pers. comm.). Date Species Sample Siz e 0 50 100 150 200 250 300 400 18. 4.72 Wi1debeest 28 14 •5. 3 3 1 1 1 8. 8.72 328 308 18 2 21. 8.72 • » 277 216 51 6 1 2 1 10.10.72 " 37 24 13 3. 7.73 108 54 20 10 8 6 5 1 3 1(650) 9. 6.73 173 170 3 Total I I . 951 786 110 21 12 9 6 2 4 T 10.10.72 Impala 14 14 0 13. 2.73 II 63 53 8 1 1(700) 9. 6.73 n 125 119 6 Total 202 186 14 1 1 10.10.72 B u f f a l o 223 71 74 35 32 16 5 3 3 2(500) 157 Table 7. The mean HcMaster counts on wildebeest, impala, and b u f f a l o f e c e s from S e r e n g e t i (Sachs and Sachs 1968), Kenya (Fay 1972), hunted and protected Botswana (Carmichael 1972), and t h i s study. Wildebeest Impala B u f f a l o S e r e n g e t i 411 748 328 Kenya 533 1,283 100 Hunted Botswana 130 105 P r o t e c t e d -Botswana 10 50 Selous 13 6 70 158 The average number of muscle c y s t i c e r c i , on a kilogram of body weight b a s i s , i s shown i n F i g u r e 2. Wildebeest was t h e most h e a v i l y i n f e c t e d s p e c i e s . The d i s t r i b u t i o n of these c y s t s with r e s p e c t t o t h e i r r e g i o n of o r i g i n , on a kilogram o f f l e s h b a s i s f o r a l l s p e c i e s combined, i s g i v e n i n Table 8 and shown i n F i g u r e 3. The weights of the d i f f e r e n t s p e c i e s , and the weights of t h e i r d i f f e r e n t r e g i o n s of f l e s h , i s given i n Table 9. The masseter was the most f r e g u e n t l y recognized source of c y s t s on a kilogram of f l e s h b a s i s . , The p e r i t o n e a l c a v i t i e s of ungulates are commonly i n f e c t e d with s e r o s a l c y s t i c e r c i , the f l u i d f i l l e d , b l a d d e r - l i k e c y s t s t h a t adhere to s e r o s a l s u r f a c e s . Wild ungulates i n A f r i c a tend t o b e i n f e c t e d with a s p e c i e s of c y s t i c e r c i a s s o c i a t e d with the presence of Taenia r e g i s i n t h e i r p r e d a t o r s , and domestic ungulates tend t o be i n f e c t e d with a s p e c i e s C y s t i c e c i . . . . ! . . . .. t e n u i c o l l i s f the i n t e r m e d i a t e stage of T. hvdatigena (Nelson e t a l . 1965, Sachs 1969b; D i n n i k and Sachs 1969a, Woodford and Sachs 1973). In t h i s study, except f o r b u f f a l o , e l a n d , waterbuck, and b u s h p i g , (the s p e c i e s with t h e s m a l l e s t number examined) we c o l l e c t e d s e r o s a l c y s t i c e r c i from every ungulate s p e c i e s examined, i . e . from w i l d e b e e s t , h a r t e b e e s t , warthog, zebra , and impala (Table 1). These c y s t i c e r c i were d i f f e r e n t i a t e d from c y s t i c e r c i of T. hydatigena and i d e n t i f i e d as t h e s p e c i e s normally a s s o c i a t e d with the presence of T. r e g i s i n an a r e a * s p r e d a t o r s (Sachs 1969b). Taenia r e g i s was recovered from two of the f i v e l i o n s , and the one hyaena. We recovered 87% of t h e . s e r o s a l c y s t s from the abdominal c a v i t y and 13% from the t h o r a c i c c a v i t y . Table 8. The presence of muscle c y s t i c e r c i (measles) i n the meat of several d i f f e r e n t ungulate species i n the Selous Game Reserve, 1971 - 1973. (Pre. i s the percent occurrence (preva lence) of 1 or more measles i n the p a r t i c u l a r region containing at l e a s t 1 measle c y s t . Den. i s the average number of c y s t s per kilogram of f l e s h (density) f o r a l l the animals examined; Av. i s the average number of cysts f o r the members of the species that were examined; n i s the sample s i z e . ) O v e r a l l Regions Heart L i v e r Tongue Animal : — • •— n av. pre. den. n pre. den. n pre. den. n pre. den. wildebeest 37 26. ,0 95 0. ,34 7 20 0.32 2 6 0.03 4 14 0.20 impala 28 3. ,9 64 0. ,26 1 4 0.12 3 7 0.13 0 hartebeest 17 7. ,6 71 0. ,12 0 2 17 0 . 0 8 2 33 0.16 warthog .11 3. .2 18 0. .14 1 50 0.23 0 1 50 0.27 b u f f a l o 6 1. ^3 67 0. .01 3 17 0.06 0 2 17 .0.07 eland 5 15. .6 60 0. .07 .1 100 0.22 0 1 67 0.53 average o v e r a l l 63 0, .16 32 0.16 5 0.04 30 0.21 Cont'd. Table 8 Cont'd (2) Hind Leg Front Leg F i l l e t s Chest Neck Animal ' • : : — : n pre. den. n pre. den.. n pre. den. n pre. den. n pre. den. Wildebeest 34 97 0. 41 27 77 0. 42 22 63 0. 30 19 54 0. 20 13 37 0.11 Impala 14 50 0. 36 7 25 0. 28 10 36 0. 41 1 4 0. .02 4 14 0.13 Hartebeest 10 42 0. 18 5 17 0. 07 2 17 0. 12 2 17 0. ,08 5 58 0.07 Warthog 2 100 0. 19 1 50 0. 17 1 50 0. ,03 1 50 0. ,17 0 B u f f a l o 3 50 0. ,01 2 17 0. ,0 0 0 0 Eland 3 100 0. ,06 1 67 0. ,07 2 67 0. ,07 1 33 0, .02 . 2 67 0.09 Overal1 Average 73 0. ,20 42 0. ,17 39 0. ,16 26 0. .08 29 0\07 Hip Diaphragm Brai n Lung Masseter Wi 1 de'beest 15 43 .0. .19 16 46 1. ,81 1 3 0 .08 3 9 0 .06 7 20 1.35 Impala 1 4 0, .03 3 11 .0. .77 0 0 0 0 0.0 Hartebeest 7 17 0 .18 2 8 0 .15 1 8 0 .22 0 4 83 0.93 Warthog 0 0 0 0 0 1 50 1.01 B u f f a l o 1 0 0 .0 1 0 0 .0 1 0 0 .0 0 2 0 0.0 Eland 0 33 0 .06 0 33 0 .10 0 33 1 .66 0 0 67 2.40 Overal1 Average 16 0 .08 16 0 .47 7 0 .33 2 0 .01 37 0.95 Table 9. The weights (with t h e i r standard d e v i a t i o n s ) of muscle regions of ungulate species i n the Selous Game Reserve 1971 - 1973 that were considered to be repre s e n t a t i v e of mature members of the population (males and females combined) and that were used i n c a l c u l a t i o n of the cyst d e n s i t i e s i n Table 8. Animal Sample Si ze Total Body Weight Total Meat Ht. L i v . Tong Mass H.I -g F.Lg F i l l Ches Neck Hip Diap Wi1debeest 13 mean 225. .9 76. .5 1. 01 1, .81 1 . .07 0, .62 24 .3 16.4 7.17 7. .78 9, .55 5.99 0.82 S.D. 37. ,1 0. .20 0. .32 0. 27 0, .19 3 .6 5.6 1 .87 1, .61 4, .18 1 .65 0.30 Impala 8 . mean 37. .9 15. 0 0. ,30 0. ,54 0. .14 0, .09 5 .0 2.8 1 .99 .1. .50 1. .33 1 .03 0.20 S.D.- 2. .6 0. .06 0. ,08 0. ,02 0, .01 1 .2 0.7. 0.32 0, .32 0, .85 0.42 0.02 Hartebeest • 11 mean 171. .0 63. 3 0. ,94 1. ,48 0. ,75 0. .38 18 .3 13.9 6; 00 6, .85 9, .49 " 4.36 0.79 S.D. 29. .5 0. ,12 0. ,26 0. ,17 0, .07 2 .4 4.2 1.75 2: .34 3, .62 1 .67 0.42 Warthog 1 59. .0 22. 2 0. ,39 0, .90 0. ,34 0. .36 6 .2 4.8 2.70 3, .30 2, .30 0.80 0.15 Zebra 1 274. .0 no. 3 1. 80 3, .20 1. ,05 0. .95 28 .9 16.5 11.00 11, .4 16, .8 17.8 0.84 Bu f f a l o 5 mean 656. .0 246. 1 2. ,91 8. ,57 Z. ,30 1. .23 69 .4 50.7 13.00 29. ,0 41 . 9 24.7 2.4 S.D. 83. .2 0. ,62 1. ,13 0. ,22 0. .34 13 .8 14.9 5.1 6. .0 10, .5 10.8 0.72 Eland 5 mean 488. .3 . 212. 1 2. ,74 7, .40 1 . ,13 0. .50 .75 .1 40.5 17.1 26, .4 25. .5 13.6 2.00 S.D. 75. .0 0. ,92 1. .40 0. ,20 0, .13 7 .9 7.2 3.8 .11. .9 12, .3 . 5.2 0.83 Cont'd. T a b l e 9 C o n t ' d . S . D . = S t a n d a r d d e v i a t i o n , H t . = h e a r t , L i v . = l i v e r , T o n g . = t o n g u e , Mass = m a s s e t e r , H . L g = h i n d l e g , F . L g = f r o n t l e g , F i l l = f i l l e t s , C h e s = c h e s t , D i a p = d i a p h r a g m . * Body w e i g h t was m e a s u r e d a f t e r t h e a n i m a l was b l e d . F i v e p e r c e n t was a d d e d t o a c c o u n t f o r b l o o d f 1 u i l o s s t o g i v e t h e t o t a l body w e i g h t . The b o d y w e i g h t f o r e l a n d a n d b u f f a l o was c a l c u l a t e d by c o m b i n i n g d i s j o i n t e d b o d y p a r t s . 163 The sacrum of antelope of the subfamily A l c e l a p h i n a e a re commonly i n f e c t e d with a c y s t i c e c i a s s o c i a t e d with the presence of Taenia o l n q o l i n e i i n the r e g i o n ' s hyaenas (Dinnik and Sachs 1969a, Woodford and Sachs 1973)« We c o l l e c t e d an average o f 0.9 of these c y s t i c e r c i from 55% of the wildebeest and an average o f 4.0 from 89% of the hartebeest (Table 1). They were i d e n t i f i e d as the c y s t i c e r c i which i s normally a s s o c i a t e d with the presence of T. o l n q o l i n e i i n hyaenas, although i t was n o t recovered from the one hyaena we examined., Hydatid c y s t s a r e a common i n f e c t i o n of A f r i c a n a n t e l o p e (Nelson e t a l . 1965, Woodford and Sachs 1973, Young 1975b). And l i o n s are commonly i n f e c t e d with a v a r i e t y of the a d u l t tapeworm Echinococcus g r a n n u l o s i s (Dinnik and Sachs 1972). Three s m a l l , f i b r o t i c or c a l c i f i e d c y s t s were recovered from the lungs of 2 of the 121 wildebeest examined, and 35 c y s t s (up t o 4 cm i n diameter) were recovered from the l i v e r s of 6 of 10 warthogs, and 2 o f 3 bushpigs (Table 1). We examined 7 of the c y s t s from the warthogs and found them t o be f e r t i l e ; t h a t i s , they contained s c o l i c e s with r o s t e l l a r h o o k l e t s . In c o n t r a s t , i n South A f r i c a , zebra tend to be the p r i n c i p l e i n t e r m e d i a t e host f o r h y d a t i d c y s t s (Young 1956), not warthogs o r bushpigs. Two of 5 Selous l i o n s c o n t a i n e d a d u l t Echinococcus g r a n n u l o s i s . Although Coenurus c y s t s a r e not a common i n f e c t i o n i n East A f r i c a (Nelson e t a l . 1965), we f r e g u e n t l y encountered s e v e r a l l a r g e , f l u i d - f i l l e d c o e n u r u s - l i k e c y s t s i n the abdominal c a v i t i e s o f hares (Lepus c a p e n s i s ) U n f o r t u n a t e l y , specimens were not a v a i l a b l e f o r l a t e r i d e n t i f i c a t i o n s and s u i t a b l e a d u l t host s p e c i e s f o r M u l t i c e p s spp., such as j a c k a l or genet c a t s 1 6 4 (Genetta s p p . ) , were not examined. Adult tapeworms o f the f a m i l y Anoplocephalidae i n f e c t the g a s t r o i n t e s t i n a l t r a c t s o f antelope (Bound 1968). We found H o n i e z i a spp. t o i n f e c t the s m a l l i n t e s t i n e s o f a l l bovidae examined i n t h i s study, i n c l u d i n g w i l d e b e e s t , h a r t e b e e s t , s a b l e , impala, b u f f a l o , and e l a n d (Table 1); and we found Anoplocephala spp. to i n f e c t zebra i n t e s t i n e s . S t i l e s i a h e p a t i c a y a common i n f e c t i o n of the l i v e r and b i l e ducts o f a n t e l o p e s (Sachs et a l . 1969) and other members of the cestode subfamily Thysanosominae, were not encountered during our examination of l i v e r s and s m a l l i n t e s t i n e s . Although Spirometra okumurai. a common i n f e c t i o n of l i o n s , was recovered i n a c o l l e c t i o n o f l i o n p a r a s i t e s from t h i s area (Bodgers 1974), we d i d not encounter t h i s p a r a s i t e i n our examination of l i o n p a r a s i t e s , nor d i d we f i n d i t s "spargana" l a r v a l stage d u r i n g our se a r c h f o r i t i n ant e l o p e (Sachs and Debbie 1969) . I n f e c t i o u s Diseases B a c t e r i a l and r i c k e t t s i a l : Anthrax i s a common i n f e c t i o n of A f r i c a n animals (Henning 1956, Anon. 1971, Vos 1973) and f o r s e v e r a l y e a r s was s t r o n g l y i m p l i c a t e d i n the deaths of many animals i n the study area (Appendix I ) . During the wet season of 1972r73, the numbers and s p e c i e s of suspect c a r c a s s e s were as f o l l o w s : 50 w i l d e b e e s t , 9 zebra, 5 elephant, 3 b u f f a l o , 3 impala, and 3 hippopotamus. In the f i e l d , we i n j e c t e d t i s s u e f l u i d s from c a r c a s s e s of 4 wildebeest and 1 impala i n t o 165 l a b o r a t o r y mice. The b a c t e r i o l o g i c a l department of C e n t r a l V e t e r i n a r y L a b o r a t o r y recovered B a c i l l u s a n t h r a c i s from the mice i n j e c t e d with f l u i d s from 3 of the wildebeest and from the 1 impala {appendix I) . N e c r o b a c i l l o s i s i s a common cause of e p i z o o t i c s o f hoof i n f e c t i o n s i n w i l d p o p u l a t i o n s , o c c u r r i n g e s p e c i a l l y d u r i n g wet c o n d i t i o n s (Bosen 1970), and has been i m p l i c a t e d i n such e p i z o o t i c s i n S e r e n g e t i wildebeest (Mustafa 1973) and diagnosed i n such an e p i z o o t i c i n K a l a h a r i gemsbok (Oryx q a z e l l a ) (Drager 1 9 7 5 ) - i n 1969, St o b a r t (1970) observed t h a t many w i l d e b e e s t c a l v e s had a lameness duri n g the wet season, which he a t t r i b u t e d t o hoof abscesses. He d i d not observe t h i s c o n d i t i o n d u r i n g t h i s study, but a s i m i l a r c o n d i t i o n o c c u r r e d d u r i n g the 1972 wet season i n a wildebeest p o p u l a t i o n i n the northern region of the res e r v e (F. Mes pers- ; comm.) * My post mortem examination of two of these c a l v e s r e v e a l e d a p a t t e r n of l e s i o n s t h a t was t y p i c a l of the d e s c r i p t i o n of the f u l m i n a t i n g f o o t - r o t form of n e c r o b a c i l l o s i s i n young ungulates (Rosen 1970)-. The most s t r i k i n g f e a t u r e s were the l a r g e , uncapsulated l e s i o n s i n most limb j o i n t s , i n the lungs and i n the l i v e r s . These l e s i o n s c o n t a i n e d a casseous m a t e r i a l , samples of which were submitted to the b a c t e r i o l o g y department of the C e n t r a l V e t e r i n a r y L a b o r a t o r y . From t h i s m a t e r i a l , a c u l t u r e , t e n t a t i v e l y i d e n t i f i e d as Spherophorus necrophorus, was i s o l a t e d (P-H. Hummel pers. comm.). B r u c e l l o s i s i s a common i n f e c t i o n of a f r i c a n antelope (Sachs and Staak 1966, Sachs e t a l . 1968, Groocock and Staak 1969, Vos and Niekerk 1969, Fay 1972, Cooper and Carmichael 1974). 166 Complement F i x a t i o n t e s t s and red blood c e l l p r e c i p i t i o n t e s t s by the C e n t r a l V e t e r i n a r y L a b o r a t o r y on 102 serum samples (Table 10), and Complement f i x a t i o n t e s t s by Kabate V e t e r i n a r y Laboratory on 31 s e r a (Table 11) were a l l negative f o r t h i s d i s e a s e . T h i s s u g g e s t s t h a t b r u c e l l o s i s was not present i n the animal p o p u l a t i o n s o f t h i s study-Joh ne's d i s e a s e i s ; widespread throughout the world and oc c u r s i n A f r i c a where European c a t t l e have been i n t r o d u c e d , e s p e c i a l l y i n East A f r i c a (Henning 1956). A survey of antelope s e r a i n Kenya was ne g a t i v e f o r t h i s d i s e a s e (Fay 1972). And Complement F i x a t i o n t e s t s of 48 of 51 s e r a from t h i s study by the C e n t r a l V e t e r i n a r y Laboratory (Table 10), and of 27 o f 28 s e r a by Kabate V e t e r i n a r y Laboratory (Table 11), were a l s o n e g a t i v e . Only one of the f o u r non-negative r e a c t i o n s was d e f i n i t e , the same sample having a p o s t i v i e r e a c t i o n a t both l a b o r a t o r i e s . He d i d not re c o g n i z e any p a t h o l o g i c a l l e s i o n s i n d i c a t i v e of t h i s d i s e a s e i n the animals from which these non-n e g a t i v e s e r a were taken, nor i n the other animals. C o n s i d e r i n g the g e n e r a l i n s e n s i t i v i t y of t h i s t e s t f o r t h i s d i s e a s e (Henning 1956) and the f a c t t h a t the c o n t r o l s used were not s p e c i f i c f o r the s e r a of the s p e c i e s i n t h i s study, i t i s i n a d v i s a b l e t o c o n s i d e r these f o u r non-negative r e a c t i o n s as po s i t i ve i n d i c a t i o n s of the presence of Johne's Disease i n these animal p o p u l a t i o n s . Contagious Bovine Pleuropneumonia (CBPP) i s a common i n f e c t i o n i n East A f r i c a n c a t t l e (Henning 1956), e s p e c i a l l y i n lowland r e g i o n s . A s e r o l o g i c a l survey of 650 w i l d ungulates i n Kenya found no p o s i t i v e i n d i c a t i o n s of i t s presence (Fay 1972). 167 Table 10. The r e s u l t s of the Central V e t e r i n a r y Laboratory's screening of sera of several ungulate species i n the Selous Game Reserve, 1971 - 1973 (P.H, . Hummel, pers. comm.). Di sease Species Sample Negative + ++ +++ ++++ Si ze Bruce!1osi s Impala 41 41 Wi1debeest 31 .31 Hartebeest 13 13 Warthog 8 8 Eland 6 6 Bu f f a l o 2 2 Zebra 1 1 Total 102 102 0 0 0 0 Johne's Wi1debeest 29 26 2 1 Di sease Impala 9 9 Hartebeest 7 7 Eland 3 3 Warthog 2 2 Zebra 1 1 Total 51 48 2 1 Q^fever Impala 41 26 2 5 8 Wildebeest 31 27 2 2 Hartebeest 13 9 2 1 1 Warthog 8 8 Eland 6 6 Bu f f a l o 2 2 Zebra 1 1 Total 102 79 2 4 8 ' 9 Table 11. The r e s u l t s of the Kabate Veterinary Laboratory's screening of sera of several ungulate species i n the Selous.Game Reserve, 1971-1973 (D.P. K a r i u k i i pers. comm.). Disease Species e Negative Suspicious S i g n i f i c a n t Brucel l o s i s Impala 19 19 Wi1debeest 7 7 Hartebeest 1 1 B u f f a l o 1 1 Zebra 1 1 Warthog 1 1 Total 31 31 Johne's Impala 19 19 Disease Wildebeest 7 6 Hartebeest 1 1 Warthog 1 1 Total 28 27 Contagious Impala 19 . 19 bovine p l e u r - Wi1debeest 7 7 pneumonia 1 Hartebeest 1 Warthog 1 1 Total 28 28 Foot-and-mouth Impala 19 19 Di sease * Wildebeest 7 7 Type A and C Hartebeest 1 1 Warthog 1 1 Total 28 28 Type 0 Impala 19 18 Wi ldebeest 7 7 Hartebeest . "1 1 Warthog 1 1 Total 28 27 T a b l e 11 C o n t ' d . 169 D i s e a s e S p e c i e s S a m p l e S i z e N e g a t i ve S u s p i c i o u s T y p e SAT 1 I m p a l a 19 4 15 W i l d e b e e s t 7 7 H a r t e b e e s t 1 1 W a r t h o g 1 1 T o t a l 28 13 15 Type SAT 2 I m p a l a 19 17 2 W i 1 d e b e e s t 7 7 H a r t e b e e s t 1 1 W a r t h o g 1 1 T o t a l 28 26 2 S i g n i f i c a n t 170 Complement F i x a t i o n t e s t s found no p o s i t i v e i n d i c a t i o n s of the presence o f t h i s d i s e a s e i n 28 sera from t h i s study (Table 11)., He a l s o d i d not r e c o g n i z e any animals with the symptoms of t h i s d i s e a s e , which suggests t h a t i t was not present i n the animal p o p u l a t i o n s of t h i s study. P o s i t i v e s e r o l o g i c a l r e a c t i o n s t o Q-fever are found i n e s s e n t i a l l y every s e r o l o g i c a l survey t h a t i s performed on s u i t a b l e host s p e c i e s anywhere i n the world ( B e l l 1970), i n c l u d i n g A f r i c a (Hummel 1976).Complement F i x a t i o n t e s t s found 23 of 102 s e r a from t h i s study to be p o s i t i v e f o r t h i s d i s e a s e (Table 10) as d e s c r i b e d by Hummel (1976) ..Although we d i d not rec o g n i z e p a t h o l o g i c a l l e s i o n s i n d i c a t i v e of t h i s d i s e a s e i n any. of the animals w i t h p o s i t i v e r e a c t i o n s or i n any of the o t h e r animals i n t h i s study, the p o s i t i v e s e r o l o g i c a l r e a c t i o n s are d e f i n i t e i n d i c a t i o n s of the presence of t h i s d i s e a s e i n these animals. He d i d not recognize p a t h o l o g i c a l l e s i o n s o f any of the other common b a c t e r i a l or r i c k e t t s i a l d i s e a s e s o f East A f r i c a n u ngulates, such as t u b e r c u l o s i s , heartwater, and l e p t o s p i r o s i s , which suggests t h a t none, of these d i s e a s e s were present i n the animal p o p u l a t i o n s o f t h i s study. V i r a l ; P o s i t i v e s e r o l o g i c a l r e a c t i o n s t o Foot-and-mouth Disease a re common i n A f r i c a n ungulates (Condy e t a l . 1969, Fay 1972, Anderson e t a l - 1975). The c l o s e r t h e i r a s s o c i a t i o n with European c a t t l e , t he more they tend t o have p o s i t i v e r e a c t i o n s t o the s t r a i n s of European o r i g i n i . e . Type A+C, and O. A f r i c a n ungulates with a very d i s t a n t a s s o c i a t i o n with European c a t t l e o f t e n have p o s i t i v e r e a c t i o n s t o Types SAT 1 and SAT 2 however 17.1 (Henning 1956, Plowright 1968, F a l c o n e r 1 9 7 2 ) N e u t r a l i z a t i o n r e a c t i o n s f o r Types A +.C and 0 on 28 sera from t h i s survey were a l l n e g a t i v e , except f o r one s u s p i c i o u s r e a c t i o n t o Type 0. N e u t r a l i z a t i o n r e a c t i o n s t o Type SAT 1 were ne g a t i v e f o r 15 s e r a ; but t h e r e were two s u s p i c i o u s l y p o s i t i v e r e a c t i o n s t o Type SAT 2 (Table 11). The f a c t t h a t none of these animals with s u s p i c i o u s l y p o s i t i v e r e a c t i o n s , nor any o f the other a n i m a l s , had p a t h o l o g i c a l l e s i o n s i n d i c a t i v e of the d i s e a s e , i n a d d i t i o n t o the f a c t t h a t a l l of these r e a c t i o n s were i n impala s e r a - a s p e c i e s i n which p o s i t i v e r e a c t i o n s are usualy suspect -suggests t h a t i t i s i n a d v i s a b l e t o c o n s i d e r these s u s p i c i o u s l y p o s i t i v e s e r o l o g i c a l r e a c t i o n s as d e f i n i t e i n d i c a t i o n s o f the presence of t h i s d i s e a s e ( e s p e c i a l l y , the Type 0 s t r a i n ) i n the animal p o p u l a t i o n s of t h i s study. Rinderpest i s v i r t u a l l y e r a d i c a t e d from e a s t e r n A f r i c a except f o r remote l o c a l i t i e s i n E t h i o p i a . N e u t r a l i z a t i o n r e a c t i o n s t o r i n d e r p e s t performed on 44 sera from t h i s study were a l l negative (Table 12). T h i s suggests t h a t the d i s e a s e was not present i n the animal p o p u l a t i o n s of t h i s study-Wildebeest and hartebeest are important r e s e r v o i r s of Malignant C a t a r r h a l Fever i n A f r i c a (Rweyemamu e t a l . 1974, P l o w r i g h t e t a l . 1 9 6 0 ) . N e u t r a l i z a t i o n r e a c t i o n s t o t h i s d i s e a s e were p o s i t i v e i n 6 of 6 wildebeest s e r a and 1 of 1 h a r t e b e e s t s e r a , and were s u s p i c i o u s i n J of 20 impala s e r a from t h i s study (Table 12). Although no p a t h o l o g i c a l l e s i o n s i n d i c a t i v e o f t h i s d i s e a s e were r e c o g n i z e d i n these animals, or i n any of the other animals, the s e r o l o g i c a l r e s u l t s a r e d e f i n i t e i n d i c a t i o n s of the presence of the d i s e a s e i n the animal p o p u l a t i o n s of t h i s study. 172 T a b l e 1 2 . The r e s u l t s o f t h e E a s t A f r i c a n V e t e r i n a r y R e s e a r c h O r g a n i z a t i o n ' s s c r e e n i n g o f s e r a o f s e v e r a l u n g u l a t e s p e c i e s i n t h e S e l o u s Game R e s e r v e , 1 9 7 1 - 1 9 7 3 (,-D.M. J e s s e t o e r s . c o m m . ) . Di s e a s e S p e c i e s S a m p l e S i ze N e g a t i v e T r a c e S i g n i f i c a n t Ri n d e r p e s t I m p a l a Wi 1 d e b e e s t H a r t e b e e s t W a r t h o g Z e b r a T o t a l 24 12 4 2 2 44 24 12 4 2 2 44 M a i i g n a n t c a t a r r h a l f e v e r I m p a l a ' W i 1 d e b e e s t H a r t e b e e s t W a r t h o g T o t a l 20 6 1 1 28 17 0 0 1 18 I n f e c t i o u s b o v i ne r h i n o -t r a c h e i t i s I m p a l a Wi 1 d e b e e s t H a r t e b e e s t W a r t h o g T o t a l 19 7 1 1 28 19 3 1 1 24 S w i n e f e v e r W a r t h o g 1 1 173 P o s i t i v e s e r o l o g i c a l r e a c t i o n s t o I n f e c t i o u s Bovine R h i n o t r a c h e i t i s and the r e l a t e d Mucosal Disease are widespread i n A f r i c a n antelope (Fay 1972, Hunter and Carmichael 1975, Hampton and J e s s e t t 1976). N e u t r a l i z a t i o n r e a c t i o n s to I n f e c t i o u s Bovine B h i n o t r a c h e i t i s were p o s i t i v e and s u s p i c i o u s l y p o s i t i v e i n 4 of 7 wildebeest s e r a (Table 12), as o u t l i n e d by Hampton and J e s s e t t (1976). Although no p a t h o l o g i c a l l e s i o n s were r e c o g n i z e d i n any of these animals, these r e s u l t s suggest the presence of t h i s d i s e a s e i n the animal p o p u l a t i o n s of t h i s study. A f r i c a n Swine Fever seldom i n f e c t s warthogs (Plowright e t al..,1969). The n e u t r a l i z a t i o n r e a c t i o n s t o the 1 warthog s e r a from t h i s , s t u d y was ne g a t i v e (Table 12). Be a l s o d i d not re c o g n i z e any p a t h o l o g i c a l l e s i o n s i n d i c a t i v e of any of the f o l l o w i n g v i r a l i n f e c t i o n s i n w i l d animals i n E a s t A f r i c a : r a b i e s , bluetongue. R i f t V a l l e y Fever, A l l e r t o n - t y p e v i r u s , distemper, and N a i r o b i Sheep Disease. T h i s suggests t h a t they were not present i n the animal p o p u l a t i o n s o f t h i s study. Anomalies P e r c i v a l (1918: 303) s a i d t h a t i n the twenty-odd y e a r s he spent among the game i n south and B r i t i s h . E a s t A f r i c a he found only a few s i c k animals. But Cowan (1951) suggests t h a t , because of the nature of our c o n t a c t with these animals, o n l y those t h a t are c r i t i c a l l y i l l are re c o g n i z e d as i l l . 174 The only n a t u r a l l y d i s a b l e d animal we encountered d u r i n g the 27 months o f my f i e l d study was a young elephant, who had a traumatic i n j u r y to i t s h i n d l e g (Gainer 1973)- And I would suppose t h a t we onl y encountered him because the elephant group p r o t e c t e d him from those predators which e l i m i n a t e most d i s a b l e d animals, and because elephants cannot e a s i l y escape the n o t i c e of humans. During the examination of the m a x i l l a e of almost 1,500 wilde b e e s t , we encountered one b i l a t e r a l and t h r e e u n i l a t e r a l i m p actions of f o u r t h premolars, and two b i l a t e r a l cases o f p e r i a l v e o l a r p e r i o s t i t i s of the molars. These c o n d i t i o n s a r e common i n s e v e r a l other ungulate s p e c i e s (Cowan 1946, Frank 1969, Mech e t a l 1970, M i l l e r and T e s s i e r 1971, M i l l e r e t a l . 1975) - y We o c c a s i o n a l l y encountered abnormal elephant i v o r y i n the f i e l d . My examination of the government " i v o r y room" r e v e a l e d the presence of s u b s t a n t i a l numbers of many d i f f e r e n t k i n d s of abnormal i v o r y . My h i s t o l o g i c a l examination of a c r o s s - s e c t i o n of a p r o l i f e r a t i v e - t y p e specimen r e v e a l e d t h a t the " p i t h " was composed of dentine with a normal appearance, and an outer l a y e r o f cementum (bark) with a normal t h i c k n e s s . 175 D i s c u s s i o n The remoteness o f t h i s study area i s of s i g n i f i c a n c e when c o n s i d e r i n g the o r i g i n of the d i s e a s e s which were recog n i z e d or capable of being r e c o g n i z e d . . F a c t o r s that must a l s o be c o n s i d e r e d are t h e i r method of t r a n s m i s s i o n and the s u i t a b i l i t y of the environmental c o n d i t i o n s f o r t h e i r l i f e c y c l e . The o r i g i n of a d i s e a s e i s important knowledge when i t s e r a d i c a t i o n i s contemplated. T r i c h i n o s i s i s e s p e c i a l l y w e l l adapted t o an urban man, garbage, r a t (Rattus r a t t u s ) , garbage-fed-pig (Suis s u i s ) s i t u a t i o n ; as was formerly a p a r t of European c u l t u r e . Human se t t l e m e n t s , a l l of which are s m a l l , s c a t t e r e d and i n f e s t e d with r a t s , are e a s i l y w i t h i n the range o f the hyaenas i n t h i s study; but domestic p i g s a r e w e l l o u t s i d e t h i s range. The one hyaena we examined was i n f e c t e d with t r i c h i n e l l a , but the 13 warthogs and bushpigs were not. T h i s suggests that the r a t - r a t p r e d a t o r r e l a t i o n s h i p may be a b a s i c component of the t r i c h i n o s i s l i f e c y c l e . H y d a t i d o s i s - e c h i n o c o c c i s i s e s p e c i a l l y w e l l s u i t e d to the domestic sheep-sheep dog s i t u a t i o n . I t s presence i n t h i s study suggests t h a t t h i s may not have been the o r i g i n a l r e l a t i o n s h i p . Most A f r i c a n communities i n c a t t l e r e a r i n g r e g i o n s do not have sewage systems or "outhouses'*. People e l i m i n a t e (at n i g h t u s u a l l y ) on the ground, which c r e a t e s i d e a l c o n d i t i o n s f o r a C y s t i c e r c u s b o v i s i n f e c t i o n i n c a t t l e and a Taenia s a g i n a t a i n f e c t i o n i n humans - i n f e c t i o n s which are very p r e v a l e n t i n such r e g i o n s (Nelson e t a l . 1965). The low numbers of humans. 176 the absence of domestic dogs, and the s o l e e x i s t e n c e of Taenia spp- (with only t h e i r a s s o c i a t e d c y s t i c e r c i ) which are i n c a p a b l e of i n f e c t i n g humans, f u r t h e r i n d i c a t e s the host s p e c i f i c i t y o f these r e l a t i o n s h i p s The t r a d i t i o n a l p r a c t i c e of many A f r i c a n communities of making dead or dying people a v a i l a b l e t o p r e d a t o r s i s thought to be an important f a c t o r i n the l e v e l of spargana and O i b o t h r i o c e p h a l i d a e i n f e c t i o n s (Nelson e t a l . 1965). The a s s o c i a t i o n of low human numbers with a low l e v e l of these i n f e c t i o n s i n t h i s study supports t h i s c o n t e n t i o n . Anthrax i s a very t r a n s p o r t a b l e d i s e a s e , e s p e c i a l l y when c a r r i e d by v u l t u r e s . I t has been known i n A f r i c a s i n c e t h e time of Moses (Klemm and Klemm 1959), which suggests t h a t the d i s e a s e has had a l e n g t h y r e l a t i o n s h i p with the p o p u l a t i o n s i n t h i s s tudy* T h i s s u g g e s t i o n i s supported by the f a c t t h a t w i l d e b e e s t appear to have a l i f e h i s t o r y s t r a t e g y which i s adapted to the presence of anthrax, Spherophorus necrophorus i s a widespread and common organism. The o b s e r v a t i o n s t h a t wildebeest a v o i d wet, black c o t t o n s o i l (Talbot and T a l b o t 1963), c o n d i t i o n s a s s o c i a t e d with the occurrence of e p i z o o t i c s of the f o o t r o t form i n c a l v e s , suggests t h a t wildebeest have had a l e n g t h y r e l a t i o n s h i p with the d i s e a s e d u r i n g which t h i s behavior p a t t e r n was e v o l v e d . Wildebeest and h a r t e b e e s t are known to be very important r e s e r v o i r s of i n f e c t i o n f o r Malignant C a t a r r h a l Fever (fiweyemamu et al.,1974) and I n f e c t i o u s Bovine B h i n o t r a c h e i t i s (Karstad e t a l . 1974). As d i r e c t c o n t a c t i s the b a s i s of t h e i r t r a n s m i s s i o n and the p o p u l a t i o n s i n t h i s study have had no h i s t o r y of d i r e c t 177 c o n t a c t with domestic animals, the r e s u l t s of t h i s study suggest t h a t w i l d ungulate r e s e r v o i r s of these d i s e a s e s are of n a t u r a l o r i g i n . Although Q-fever i s t r a n s m i t t e d by i n s e c t v e c t o r s , the remoteness of t h i s r e g i o n suggests t h a t the p o s i t i v e i n d i c a t i o n s of the d i s e a s e mean t h a t i t i s n a t u r a l l y present i n wi l d ungulate p o p u l a t i o n s . The p r e v a l e n c e of s c h i s t o s o m i a s i s i s hig h e r i n domestic animals than i n w i l d animals (Dinnik and Dinnik 1965, P i t c h f o r d et a l . i n p r e p . ) , which suggests t h a t humans and domestic animals a r e the source of i n f e c t i o n f o r wild animals. The low number of humans, the non-existence of domestic mammals, and t h e absence o f schistosomes i n t h i s study supports t h i s h y p o t h e s i s . The absence o f warbles, l i v e r f l u k e s , D i c t y o c a u l i d a e lungworms, T h e l a z i a eyeworms, and S t i l e s i a spp. might be due to the u n s u i t a b i l i t y o f the environment i n t h i s s t udy. But i s more l i k e l y due to the absence of domestic mammals, e s p e c i a l l y c a t t l e . As only 5 cows and a b u l l of European o r i g i n a r e co n s i d e r e d r e s p o n s i b l e f o r the i n t r o d u c t i o n o f l i v e r f l u k e s to Madagascar, the absence o f these p a r a s i t e s i n t h i s study i s a good i n d i c a t i o n of the i n s i g n i f i c a n c e of the presence of the few domestic animals i n the study r e g i o n . Wild ungulate p o p u l a t i o n s have not been a permanent r e s e r v o i r of r i n d e r p e s t i n f e c t i o n because t h e i r " b i r t h p u l s e " type of r e p r o d u c t i o n prevents t h e r e being a continuous supply of s u s c e p t i b l e animals. T h i s i s important because the i n f e c t i o n o c curs only once d u r i n g an animal's l i f e t i m e and l a s t s f o r on l y a s h o r t p e r i o d o f time. So, when r i n d e r p e s t was e r a d i c a t e d from 178 the c a t t l e p o p u l a t i o n s surrounding the w i l d a n i m a l , p o p u l a t i o n s , the continuous source of i n f e c t i o n was e l i m i n a t e d and the d i s e a s e disappeared i n the wild p o p u l a t i o n s (Plowright and Mcculloch 1967, T a y l o r and Watson 1967). The n e g a t i v e s e r o l o g i c a l r e s u l t s i n t h i s study suggest that the d i s e a s e was e i t h e r never i n t r o d u c e d , or e l i m i n a t e d approximately 12 years ago - 12 being the age o f the o l d e s t animal from which serum was t e s t e d . F a l c o n e r (1972) and Anderson e t a l . (1975) found t h a t when Foot-and-mouth Disease was e l i m i n a t e d •from domestic animal p o p u l a t i o n s , i t disappeared from the wild animal p o p u l a t i o n s , i n c l u d i n g the very suspect impala { s e r o l o g i c a l r e a c t i o n s were not t h e i r o n l y b a s i s ) . T h i s i n d i c a t e s t h a t domestic animals might be the source of the d i s e a s e . The r e s u l t s of t h i s study n e i t h e r support nor d i s c o n f i r m t h i s h y p o t h e s i s , but they do emphasize the c o n s i s t e n c y of p o s i t i v e r e a c t i o n s of impala s e r a t o the n e u t r a l i z a t i o n t e s t f o r t h i s d i s e a s e . Rweyemamu e t a l . (1973) noted t h a t the prevalence of r a b i e s was a s s o c i a t e d with the d e n s i t y of dogs and not with the e x i s t e n c e of w i l d c a r n i v o r e s . T h i s study f u r t h e r suggests t h a t t h i s d i s e a s e i s not of w i l d animal o r i g i n * The abnormal growth o f elephant i v o r y i s thought to be of t r a u m a t i c o r i g i n p r i m a r i l y : and many elephants t h a t are shot i n the f a c e escape. I f e l e p h a n t s were shot i n a more r e s p o n s i b l e manner, the p r e v a l e n c e of t h i s poor q u a l i t y form of i v o r y would decrease as would the number o f b e l i g e r a n t e l e p h a n t s a s s o c i a t e d with abnormal i v o r y . 179 P a r t I I . Management C o n s i d e r a t i o n s I n t r o d u c t i o n I f the manager of a w i l d animal p o p u l a t i o n i s to manage h i s animals p r o p e r l y , he must know the answers to s e v e r a l important q u e s t i o n s about the p a r a s i t e s and d i s e a s e s which i n f e c t h i s wild animal p o p u l a t i o n s . He has e x p e r t s a t h i s d i s p o s a l , but f r e q u e n t l y he does not know what q u e s t i o n s t o ask them, and consequently does not o b t a i n t h e i n f o r m a t i o n he needs. My ex p e r i e n c e as a v e t e r i n a r i a n and Game Management O f f i c e r with the Tanzania Game D i v i s i o n i n d i c a t e s t h a t the f o l l o w i n g q uestions should be asked by any manager of w i l d animal p o p u l a t i o n s : (1) What adverse e f f e c t s do the p a r a s i t e s and d i s e a s e s which i n f e c t h i s wild animals have on (a) the w i l d animal p o p u l a t i o n s themselves; .(b). on the domestic animals which a s s o c i a t e with those p o p u l a t i o n s ; and (c) on the humans who s t a f f o r v i s i t the r e g i o n i n which h i s animals l i v e ? (2) What adverse e f f e c t s do the p a r a s i t e s and d i s e a s e s of human and domestic animal o r i g i n s have on h i s wild animal p o p u l a t i o n s ? The f i r s t s t e p i n answering these q u e s t i o n s i s to i d e n t i f y as completely as p o s s i b l e the p a r a s i t e s and d i s e a s e s which i n f e c t the r e l e v a n t animal and human p o p u l a t i o n s ( i . e . those l i v i n g w i t h i n the managers a r e a s o f r e s p o n s i b i l i t y ) . Once these have been i d e n t i f i e d , the e f f e c t s they have on the w i l d and domestic animal p o p u l a t i o n s and on humans can be obtained from the l i t e r a t u r e . The Merck Manuels on Human (Berkow 1977) and V e t e r i n a r y (Siegmund 1973) Medicine are two e x c e l l e n t sources of 1 8 0 such i n f o r m a t i o n . The best source, however, i s the ne a r e s t V e t e r i n a r y D i a g n o s t i c Laboratory- I f asked the q u e s t i o n s o u t l i n e d above, the personnel a t these e s t a b l i s h m e n t s w i l l i p r o v i d e him with the knowledge he needs. For i l l u s t r a t i v e purposes, I s h a l l present the i n f o r m a t i o n which the manager o f the Selous Game Beserve should know about the p a r a s i t e s and d i s e a s e s which I encountered i n my survey of animals i n the Selous. T h i s i s based on my knowledge of these i n f e c t i o n s and the d i s e a s e s of human and domestic animals i n t h a t r e g i o n . a. The adverse E f f e c t s of P a r a s i t e s and Diseases Which I n f e c t Wild animals of the Selous Game Beserve I . On the Wild animal P o p u l a t i o n s : Whether the e f f e c t s of p a r a s i t e s and d i s e a s e s on the wi l d animals p o p u l a t i o n s aire c o n s i d e r e d adverse depends on what the po p u l a t i o n s are being managed f o r . I f the manager simply wants the p o p u l a t i o n s i n t h e i r n a t u r a l s t a t e , then the e f f e c t s on those p o p u l a t i o n s of the p a r a s i t e s and di s e a s e s I encountered w i l l not be co n s i d e r e d d e t r i m e n t a l . T h i s i s because these p a r a s i t e s and d i s e a s e s have probably been e s t a b l i s h e d n a t u r a l l y and have evolved a balanced r e l a t i o n s h i p * T h e r e f o r e , an i n f e c t i o n would not a d v e r s e l y a f f e c t a host t h a t was an advantage t o i t s own p o p u l a t i o n f o r reasons d i s c u s s e d e a r l i e r i n my t h e s i s . 181 But i f the manager wants t o maintain the p o p u l a t i o n s f o r some kind of p r o d u c t i v e purposes, or simply wants to e l i m i n a t e as f a r as p o s s i b l e i n d i v i d u a l deaths, the e f f e c t s of some p a r a s i t e s and d i s e a s e s w i l l be c o n s i d e r e d adverse. The i n f e c t i o n s which were r e s p o n s i b l e f o r the l o s s of animal l i f e were anthrax and n e c r o b a c i l l o s i s . Anthrax caused the death of members of most ungulate s p e c i e s ; and i t i s capable of causing death i n a l l mammalian s p e c i e s . N e c r o b a c i l l o s i s caused the death o f wildebeest calves., The i n f e c t i o n s which were a s s o c i a t e d with p a t h o l o g i c a l l e s i o n s i n t h e i r h o s t s , and which might have predisposed those animals t o p r e d a t i o n , were A r m i l l i f e r a r m i l l a t u s l a r v a e , Agriostomum spp. hookworms, abomasal nematodes and o e s t r i d f l y l a r v a e . A r m i l l i f e r a r m i l l a t u s l a r v a e were found i n a s t u n t e d , i n f e r t i l e h a r t e b e e s t ; Agriostomum spp, were found i n the inflammed s p i r a l c o l o n s of two wild e b e e s t ; abomasal nematodes were o c c a s i o n a l l y found i n inflammed abomasa i n most ruminant s p e c i e s ; and o e s t r i d f l y l a r v a e were o c c a s i o n a l l y a s s o c i a t e d with a n a s a l s i n u s i t i s i n wildebeest and h a r t e b e e s t . I I . On Humans: I n f e c t i o n s from the environment: The w i l d animal p o p u l a t i o n s supported the e x i s t e n c e of t s e t s e , l i o n , bot, and chrysops f l i e s ; t i c k s ; and mosquitoes. T s e t s e and l i o n f l i e s , t i c k s and mosquitoes suck the bloo d o f humans as w e l l as w i l d animals. And the l a r v a e of chrysops f l i e s (mango worms) burrow i n t o wounds. Humans u s u a l l y c o n t r a c t t h i s l a t t e r i n f e c t i o n by wearing c l o t h e s 182 t h a t have been d r i e d on v e g e t a t i o n i n f e c t e d with the l a r v a e . The l a r v a e a t t a c h t o the c l o t h e s and l a t e r a t t a c h t o the humans who wear them. i The l a r v a e o f bot f l i e s , G e d o e l s t i a h a e s s e l e r i . found i n the n a s a l s i n u s e s of h a r t e b e e s t , and i n the n a s a l s i n u s e s and b r a i n c a v i t y , of wi l d e b e e s t , cause an eye i r r i t a t i o n and even b l i n d n e s s i n human p o p u l a t i o n s which are c l o s e l y a s s o c i a t e d with these host p o p u l a t i o n s (Dutoit and Heyer 1960, B i s l e y 1972). The a d u l t f l y s t r i k e s the person around the eye, d e p o s i t i n g .small l a r v a e which attempt t o migrate to the b r a i n . Although t h e r o l e of wild animals i n epidemics of human s l e e p i n g s i c k n e s s — a c h r o n i c , d e b i i l i t a t i n g i n f e c t i o n which i n v o l v e s the nervous system i n i t s advanced s t a g e s , — i n Ea s t e r n A f r i c a i s not completely c l e a r , i t appears t h a t c e r t a i n s p e c i e s (such as the bush buck. Traqelaphus s c r i p t u s . i n t h i s region) can a c t as a r e s e r v o i r and source o f i n f e c t i o n (Nash 1969)* The t r a n s m i s s i o n of t h i s d i s e a s e i s by t s e t s e f l y . The occurrence o f Spirometra spp. i n a l i o n (Rodgers 1974) means t h a t the stagnant water i n t h i s r e g i o n i s a p o t e n t i a l source of spargana i n f e c t i o n s , ; the i n t e r m e d i a t e form of t h i s p a r a s i t e (Nelson e t a l . 1965). T h i s i s a long, helminthe l i k e l a r v a e t h a t e n c y s t s under the s k i n . I n f e c t i o n s from c l o s e c o n t a c t with animals: The most s e r i o u s i n f e c t i o n of t h i s type i s anthrax. The u s u a l m a n i f e s t a t i o n , a p u s t u l e or malignant c a r b u n c l e on the hands (cutaneous a n t h r a x ) , i s c o n t r a c t e d by handling the remains of animals t h a t have d i e d from the d i s e a s e . Untreated malignant c a r b u n c l e s cause a g e n e r a l i z e d malaise and even death. T h i s 183 d i s e a s e i s a l s o f r e q u e n t l y c o n t r a c t e d by e a t i n g meat from an animal which was dead or dying from anthrax. C o n t r a c t i n g i t i n t h i s way w i l l g i v e r i s e t o the much more dangerous i n t e s t i n a l form of the d i s e a s e . The even more dangerous r e s p i r a t o r y form i s u s u a l l y , only c o n t r a c t e d by people working i n dusty, h i d e - s o r t i n g rooms. The i n g e s t i o n o f eggs, and subsequent c o n t r a c t i o n o f h y d a t i d or coenurus c y s t s by humans, i s u s u a l l y a s s o c i a t e d with people t h a t have handled f e c a l m a t e r i a l , or m a t e r i a l s i n c o n t a c t with f e c a l m a t e r i a l , of c a r n i v o r e s i n f e c t e d with Ech ninococcus q r a n n u l o s i s or M n l t i c e p s spp. tapeworms, r e s p e c t i v e l y . These l a r g e c y s t s u s u a l l y i n f e c t the v i s c e r a l organs of humans. But they o c c a s i o n a l l y i n f e c t the c e n t r a l nervous system and, when they do, are o f a s e r i o u s n a t u r e . I n the S e l o u s , l i o n s , hyaenas, le o p a r d s , and w i l d dogs are a l l s u i t a b l e hosts f o r Echninococcus q r a n n u l o s i s , and the s m a l l e r p r e d a t o r s are s u i t a b l e h o s t s f o r H u l t i c e p s spp. The i n g e s t i o n of eggs and subsequent c o n t r a c t i o n of pentastornid l a r v a l i n f e c t i o n s by humans i s a s s o c i a t e d with people who have handled the n a s a l c a v i t i e s , or m a t e r i a l a s s o c i a t e d with the n a s a l c a v i t i e s , of s u i t a b l e c a r n i v o r e s p e c i e s . In the S e l o u s , l i o n s , hyaenas, l e o p a r d s and w i l d dogs were s u i t a b l e hosts f o r the l i n g u a t u l i d - t y p e pentastomes; and snakes, e s p e c i a l l y the python, were s u i t a b l e f o r A r m i l l i f e r a r m i l l a t u s . The l a t t e r l a r v a l i n f e c t i o n i s e s p e c i a l l y s e r i o u s (Sweatman 1971), and can cause i n humans a severe g e n e r a l i z e d d e b i l l i t a t i o n . 184 I n f e c t i o n s from meat: Probably the most important i n f e c t i o n i n t h i s c ategory i s the 1 i n g u a t u l i d - t y p e pentastomes. Pentastomid l a r v a e i n f e c t e d the v i s c e r a l lymph nodes { e s p e c i a l l y the t h o r a c i c ) o f every ruminant s p e c i e s {the u s u a l meat s p e c i e s ) examined. In a d d i t i o n , they i n f e c t e d the v i s c e r a l organs, i n c l u d i n g the h e a r t , l i v e r , and kidney, of b u f f a l o . The i n g e s t i o n o f thes e l a r v a e ( u s u a l l y by e a t i n g i n a d e q u a t e l y cooked meat) g i v e s r i s e to an o f t e n severe i r r i t a t i o n of the l a r y n x and pharynx known as the halzoun and marrara syndrome (Sweatman 1971) . Anthrax i s a l s o an important i n f e c t i o n because people sometimes eat animals t h a t are dead or dying o f t h i s d i s e a s e . In f a c t , the v e t e r i n a r y a u t h o r i t i e s i n many t h i r d world c o u n t r i e s are u s u a l l y aware of the presence o f t h i s d i sease because of i t s d i a g n o s i s i n people who have eaten i n f e c t e d meat. He found t r i c h i n o s i s i n one hyaena, so i t i s p o t e n t i a l l y present i n any s p e c i e s which scavenges i n the Selous. T h i s i n c l u d e s warthog and bushpig, two s p e c i e s which are of l i t t l e importance to the d i e t of most East A f r i c a n commmunities. The d i s e a s e s which were r e s p o n s i b l e f o r most of the s e r i o u s i l l n e s s e s i n the human p o p u l a t i o n were those which are t y p i c a l l y a s s o c i a t e d with human s e t t l e m e n t s . M a l a r i a , i n p a r t i c u l a r accounted f o r about 50% of the h e a l t h problems. The v i r a l - l i k e r e s p i r a t o r y i n f e c t i o n , which o c c u r r e d d u r i n g the change from the wet t o the dry season, and a n o n - s p e c i f i c dysentry were the next most common causes o f i l l n e s s . In a d d i t i o n , r e l a p s i n g f e v e r or s p i r i l l o s i s (a d i s e a s e o f p o s s i b l e w i l d animal o r i g i n ) -- was diagnosed on two occ a s i o n s . 185 There was no s p e c i f i c attempt to c o l l e c t i n f o r m a t i o n on the i n f e c t i o n s of w i l d animal o r i g i n . However, f i v e s t a f f members had malignant c a r b u n c l e s (cutaneous anthrax) on t h e i r hands. These were people whose work i n v o l v e d the c o l l e c t i o n o f animal remains. Three of these c a s e s were diagnosed on the b a s i s of s t a i n e d smears from the i n f e c t i o n s , the other two on the b a s i s of a p u s t u l e , swollen a x i l l a r y lymph nodes and a f e v e r . H i s t o r i c a l l y , human s l e e p i n g s i c k n e s s was a d i s e a s e of major importance i n the Selous. S i n c e the r e l o c a t i o n of these s e t t l e m e n t s o u t s i d e o f the r e s e r v e , the d i s e a s e has not been diagnosed i n any s t a f f members. T h i s i s probably because c o n c e n t r a t i o n o f humans i s necessary f o r the occurrence of epidemics. I I I . Domestic Animals Almost every one of the p a r a s i t e s and d i s e a s e s found i n the Selous i s capable o f i n f e c t i n g an a p p r o p r i a t e domestic animal s p e c i e s * The ones t h a t I w i l l deal with here are those t h a t are g e n e r a l l y c o n s i d e r e d to be s e r i o u s problems. Trypanosomiasis (nagana) i s by f a r the b i g g e s t problem f o r animal husbandry i n A f r i c a today (Mash 1969). I t s e x i s t e n c e i s guaranteed by the presence of wild animals and t s e t s e f l i e s . Where i t e x i s t s the husbandry of domestic animals i s commercially i m p o s s i b l e because of the c h r o n i c d e b i l l i t a t i o n i t causes i n these animals./ 186 There were i n d i c a t i o n s o f two other common bloo d p a r a s i t e s o f w i l d u ngulates — T h e l i e r i a and Anaplasma spp. T h e i l e r i o s i s , o r East Coast Fever, was by f a r the most common i n f e c t i o n a s s o c i a t e d with the dead or d e b i l l i t a t e d c a t t l e examined by the pathology department of C e n t r a l V e t e r i n a r y Laboratory ( H . Jakob pers. comm.). Anaplasmosis causes a l e s s common but s e r i o u s d i s e a s e i n c a t t l e known as g a l l s i c k n e s s . Anthrax was r e s p o n s i b l e f o r the death of many animals i n the Selous and causes enormous l o s s e s t o the l i v e s t o c k i n d u s t r i e s o f most A f r i c a n c o u n t r i e s , t o a f a r g r e a t e r extent than i s commonly r e a l i z e d (Anon. 1971) . Quarantine i s one method of c o n t r o l . R egulatory a g e n c i e s o f t e n f o r b i d the movement of animals or animal products from an area i n which anthrax o c c u r s i n f o one i n which i t does not* The m o b i l i t y of v u l t u r e s , howver, makes these r e g u l a t i o n s u s e l e s s i n A f r i c a . There were i n d i c a t i o n s t h a t Malignant C a t a r r h a l Fever and I n f e c t i o u s Bovine H h i n o t r a c h e i t i s - s e r i o u s d i s e a s e s of c a t t l e -i n f e c t e d wildebeest and h a r t e b e e s t i n the Selous.- The occurrence of Malignant C a t a r r h a l Fever has a s t r o n g a s s o c i a t i o n with w i l d animal c o n t a c t , e s p e c i a l l y c o n t a c t with wildebeest during t h e i r c a l v i n g p e r i o d s (Bweyemamu e t a l . 1974). There were minor i n d i c a t i o n s t h a t Foot-and-mouth Disease may e x i s t i n the Selous* U n t i l the v i r u s i s i s o l a t e d , however, i t cannot be assumed t o be p r e s e n t . Quarantine r e g u l a t i o n s r e s t r i c t the movement of animals, or animal products, from an a r e a i n which i t i s present. 187 The hot f l i e s from the l a r v a e found i n the n a s a l s i n u s e s o f wildebeest and har t e b e e s t of t h e Selo u s cause a s e r i o u s eye i n f e c t i o n i n domestic ungulates known as Uitpeuloog- The m i g r a t i o n of l a r v a e o f these f l i e s cause a b u l g i n g o f the eye, b l i n d n e s s , and even death. Sheep are p a r t i c u l a r l y s u s c e p t i b l e (Basson 1962) - , B. The Adverse E f f e c t s on the Animals o f the Selous of P a r a s i t e s and Diseases of Human and Domestic Animal O r i g i n Prominent p a r a s i t e s and d i s e a s e s o f o t h e r wild animal p o p u l a t i o n s which were not present in, the Selous, but which would probably be i n t r o d u c e d by human s e t t l e m e n t s and domestic animal husbandry are warbles, l i v e r f l u k e s , P i e t y c a u l u s spp. lungworms, S t i l e s i a l i v e r tapeworms, schistosomes, T h e l a z j a eye worms, t u b e r c u l o s i s , b r u c e l l o s i s , l e p t o s p i r o s i s , r a b i e s . Foot-and-mouth Disease, and bluetongue. E s s e n t i a l l y every one of these i n f e c t i o n s i s of economic importance because of the reduced p r o d u c t i v i t y o f w i l d animal p o p u l a t i o n s which they would cause. Most i n f e c t i o n s do t h i s by causing a r e d u c t i o n i n the s u r v i v o r s h i p of t h e i r wild animals hosts. ; But b r u c e l l o s i s reduces p r o d u c t i v i t y by reducing the f e r t i l i t y of i t s h o s t i S e v e r a l i n f e c t i o n s such as warbles, c y s t i c e r c o s i s , and l i v e r f l u k e s a re a l s o of economic importance because they reduce the g u a l i t y and, thus, p r i c e o f animal products. And the r e g u l a t i o n s f o r c o n t r o l l i n g Foot-and-mouth Pi s e a s e g r e a t l y reduce the number of a v a i l a b l e markets, and thus the p r i c e of animal products. Judging from the communities i n 188 s i t u a t i o n s somewhat s i m i l a r t o the Selous, b r u c e l l o s i s would be the most economically important i n f e c t i o n . . As domestic animals and humans have had a c l o s e a s s o c i a t i o n f o r many years, many shared i n f e c t i o n s have evolved, t h e most prominent ones being t u b e r c u l o s i s , r a b i e s , b r u c e l l o s i s (undulent f e v e r ) , and s c h i s t o s o m i a s i s . . But e s s e n t i a l l y , every domestic animal i n f e c t i o n has been known to i n f e c t humans, and e s s e n t i a l l y every h u m a n i n f e c t i o n has been known t o i n f e c t a common s p e c i e s of domestic animal. Under normal ci r c u m s t a n c e s , the animal with the most shared i n f e c t i o n s , i s the dog, having a t o t a l o f 64. In A f r i c a n communities i n somewhat s i m i l a r s i t u a t i o n s , s c h i s t o s o m i a s i s i s probably the i n f e c t i o n of g r e a t e s t importance; although b r u c e l l o s i s (undulent fever) would be very important as w e l l . Management Strategy As mentioned i n the beginning of my t h e s i s , the e f f e c t s a pathogen has on a h o s t depends a g r e a t d e a l on whether a d i s e a s e has been e s t a b l i s h e d n a t u r a l l y i n a host p o p u l a t i o n or has been i n t r o d u c e d . I f n a t u r a l l y e s t a b l i s h e d , then the r e l a t i o n s h i p w i l l be balanced; t h a t i s , the pathogen w i l l not a d v e r s e l y a f f e c t i t s host p o p u l a t i o n * I f a r t i f i c i a l l y e s t a b l i s h e d ( i . e . i n t r o d u c e d ) , then the r e l a t i o n s h i p w i l l be unbalanced; t h a t i s , the pathogen w i l l e i t h e r be i n c a p a b l e of i n f e c t i n g the host or i t w i l l have adverse, sometimes d i s a s t r o u s e f f e c t s . 189 The e f f e c t s a pathogen has on a host a l s o depends on whether the r e p r o d u c t i o n , p r e d a t i o n , n u t r i t i o n , and g e n e r a l success of i t s host i s c o n t r o l l e d by man or by nature. In h o s t s husbanded by man, pathogens tend to have c h r o n i c , p e r s i s t e n t e f f e c t s because the host's success i s tended to by man. But i n h o s t s i n n a t u r a l c o n d i t i o n s , pathogens tend to have minimal e f f e c t s on those h o s t s which are an advantage t o the host p o p u l a t i o n and maximal e f f e c t s on those h o s t s which a r e not an advantage to the host p o p u l a t i o n . The p a r a s i t e s and d i s e a s e s encountered i n the animals of the Selous appeared to be n a t u r a l l y e s t a b l i s h e d and so t h e i r e f f e c t s on t h e i r host p o p u l a t i o n s can be expected t o be harmless, and perhaps even b e n e f i c i a l . The p a r a s i t e s and d i s e a s e s of domestic animals a r e not adapted t o a balanced r e l a t i o n s h i p with wild animals and t h e i r e f f e c t s on such p o p u l a t i o n s are p o t e n t i a l l y d i s a s t r o u s . The e f f e c t s of r i n d e r p e s t on A f r i c a n ungulates and the e f f e c t s of myxomatosis on A u s t r a l i a n r a b b i t s are h i s t o r i c examples of the p o t e n t i a l f o r harm t h a t an i n t r o d u c e d i n f e c t i o n can cause. I n i a d d i t i o n t o these c o n s i d e r a t i o n s i s the f a c t t h a t p a r a s i t e s and d i s e a s e s o f d o m e s t i d animals are o f t e n s p e c i f i c a l l y adapted t o i n f e c t i n g humans. The dog, f o r example, shares 64 i n f e c t i o n s with humans under normal and not j u s t A f r i c a n , c i r c u m s t a n c e s . So, the i n t r o d u c t i o n of domestic animals with t h e i r accompanying i n f e c t i o n s i n c r e a s e s the number of human i n f e c t i o n s i n the r e g i o n . As humans have not been a s i g n i f i c a n t p a r t o f the Selous environment, none of the p a r a s i t e s and d i s e a s e s i n i t s w i l d animal p o p u l a t i o n s w i l l be s p e c i f i c a l l y 190 adapted t o i n f e c t i n g humans. In f a c t , t here i s probably the fewest p o s s i b l e human i n f e c t i o n s i n t h i s area given the l a r g e q u a n t i t y and v a r i e t y of animal l i f e . But, most i m p o r t a n t l y , the i n t r o d u c t i o n of domestic animals w i l l turn w i l d animals i n t o r e s e r v o i r s f o r such i n f e c t i o n s , making d i s e a s e c o n t r o l programs very c o s t l y , , and damaging t o the w i l d animal populations.. The obvious management c o n c l u s i o n s to be drawn from these c o n s i d e r a t i o n s i s t h a t p o p u l a t i o n s should not be mixed. The g r e a t e r the e p i z o o t i o l o g i c a l d i s t a n c e between human, domestic and w i l d animal p o p u l a t i o n s , the fewer w i l l be the number o f adverse i n f e c t i o n s and problems f o r the managers of human, domestic, and w i l d animal p o p u l a t i o n s . I i . C o n t r o l Measures f o r t h e Present I n f e c t i o n s At p r e s e n t , the only i n f e c t i o n i n the Selous which r e g u l a t o r y agencies might be i n t e r e s t e d i n r e d u c i n g i s anthrax. In s e v e r a l areas of the world the d i s p o s a l of c a r c a s s e s i s found to be e f f e c t i v e . T h i s can be e a s i l y and e f f e c t i v e l y done by i n c i n c e r a t i n g w i l d e b e e s t - s i z e d c a r c a s s e s with f i r e w o o d and about 50....-liters o f d i e s e l o i l . However, i n the Selous, v u l t u r e s and scavengers u s u a l l y dispose o f c a r c a s s e s i n a day- So, i n c i n e r a t i o n of c a r c a s s e s would probably not s i g n i f i c a n t l y reduce the l e v e l of anthrax organisms. Probably the best c o n t r o l measure i n the Selous would be a croppng program to reduce the number of animals i n the area 191 towards the end of the wet season (as mentioned e a r l i e r i n my t h e s i s ) -The manager and the medical attendants should be aware of the f o l l o w i n g hazards to s t a f f and v i s i t o r s : anthrax (Choguette 1970), h y d a t i d and coenurus c y s t s (Leiby and Dyer 1971) , halzoun and marrara syndrome (Sweatman 1971), and ocular m y i a s i s ( B i s l e y 1972). In a d d i t i o n , i t would be advantageous to the s t a f f and v i s i t o r s i f they a r e made aware of these d i s e a s e s and know how t o a v o i d them. I w i l l o u t l i n e below methods of avoidance. The cutaneous form of anthrax can be avoided by not h a n d l i n g s i c k animals, or the remains of animals whose death i s of unknown o r i g i n * I f they are handled, as they o f t e n must by management p e r s o n n e l , then the hands and i n c o n t a c t m a t e r i a l s s h o u l d be t h o r o u g h l y washed afterwards. The i n t e s t i n a l form of anthrax can be avoided by not consuming meat of animals t h a t were s i c k or dead of t h i s d i s e a s e * T h i s r e g u i r e s the r e s p o n s i b l e s u p e r v i s i o n of a person's meat supply (Part I I I ) . The b e s t a n t i b i o t i c f o r t r e a t i n g anthrax i s p e n i c i l l i n , not t e t r a c y c l i n e s as i s o f t e n thought. As drugs l i k e p e n i c i l l i n have been known t o cause more h e a l t h problems than they s o l v e , the treatment of people with t h i s drug should be done by g u a l i f i e d h e a l t h p e r s o n n e l . & layman should do so only when there are no g u a l i f i e d personnel a v a i l a b l e . Because h y d a t i d and coenurus c y s t s are c o n t r a c t e d by i n g e s t i n g eggs from the f e c e s of i n f e c t e d c a r n i v o r e s , people h a n d l i n g f e c a l m a t e r i a l or m a t e r i a l a s s o c i c a t e d with f e c a l m a t e r i a l o f v i r t u a l l y a l l c a r n i v o r e s s h o u l d promptly wash t h e i r 192 hands and i n c o n t a c t m a t e r i a l a f t e r w a r d s . I t i s very easy f o r a person's hands or i n c o n t a c t m a t e r i a l t o contaminate something which i s then i n t r o d u c e d i n t o h i s or someone e l s e ' s mouth. An e x c e l l e n t example of a s i t u a t i o n i n which contamination i s l i k e l y to occur i s shown i n F i g u r e 4. Because the halzoun and marrara syndrome i s c o n t r a c t e d by i n g e s t i n g i n a d e g u a t e l y cooked v i s c e r a such as l i v e r , kidney, h e a r t , or lymph nodes a s s o c i a t e d with the v i s c e r a , t h i s i n f e c t i o n can be avoided i f t h i s m a t e r i a l i s w e l l cooked. I f the v i s c e r a i s c l e a n l y removed from the c a r c a s s d u r i n g i t s butchery, then the s k e l e t a l meat w i l l be f r e e of t h i s i n f e c t i o n . We r e c o g n i z e d no p a r a s i t e s and d i s e a s e s i n the s k e l e t a l meat (other than animals dead o f anthrax) which would i n f e c t man. Pentastomid l a r v a e a r e c o n t r a c t e d by man by i n g e s t i n g eggs from the n a s a l passages of c a r n i v o r e s . So, a person h a n d l i n g c a r n i v o r e s or m a t e r i a l a s s o c i a t e d with them should wash h i s hands and i n c o n t a c t m a t e r i a l promptly aft e r w a r d s . T h i s i s of p a r t i c u l a r importance a f t e r h a n d l i n g snakes, as they are a source of a s e r i o u s l a r v a l i n f e c t i o n from A r m i l l i f e r a r m i l l a t u s . P a r t I I I . Meat I n s p e c t i o n C o n s i d e r a t i o n s Host western c u l t u r e s have l e g i s l a t i o n r e g u i r i m g meat to be i n s p e c t e d and judged f o r a c c e p t a b i l i t y by government meat i n s p e c t o r s * T h i s l e g i s l a t i o n i s designed f o r s o c i e t i e s i n which domestic animals are t r a n s p o r t e d t o c e n t r a l , well-eguipped and s t a f f e d a b b a t o i r s f o r s l a u g h t e r * In such s i t u a t i o n s , these 1 9 3 F i g u r e 4. An example of how humans can expose themselves to i n f e c t i o n s of w i l d animal o r i g i n . The l i o n ' s n a s a l area i s probably contaminated with pentastomid eggs and the a n a l areas with echinococcus eggs. Contact with these r e g i o n s s p e c i f i c a l l y , but with the animal i n g e n e r a l , c r e a t e s the p o s s i b i l i t y t h a t eggs of these p a r a s i t e s may be i n g e s t e d . The i n g e s t i o n o f these p a r a s i t e s * eggs causes a pentastomid l a r v a l and/or h y d a t i d c y s t i n f e c t i o n of v i s c e r a l organs. 194 195 r e g u l a t i o n s are eminently s u i t a b l e . But i n the s i t u a t i o n i n which game animals are h a r v e s t e d , such r e g u l a t i o n s would probably cause more harm than they do good s i n c e they would be a b a r r i e r t o the u t i l i z a t i o n of game animals f o r meat. T h i s i s because most wild animals cannot be t r a n s p o r t e d t o c e n t r a l a b b a t o i r s . And i f a b b a t o i r s were made mobile, t h e i r c o s t and the c o s t of t h e i r s t a f f would be too much to warrant the s m a l l , .uneconomic, and undependable supply o f game i n most c r o p p i n g o p e r a t i o n s . I f game animals are going to be used f o r meat by humans, then t h e i r c o l l e c t i o n , s l a u g h t e r and marketing w i l l have t o be done on a s m a l l s c a l e independent o f a b b a t o i r s ; probably along t h e l i n e s of present-day poaching o p e r a t i o n s . Q u a l i t y c o n t r o l of meat a t t h i s l e v e l of o p e r a t i o n has seldom been c o n s i d e r e d ; i t i s t o t h i s problem t h a t I now t u r n . I am a v e t e r i n a r i a n and have had experience i n meat i n s p e c t i o n and the meat supply b u s i n e s s , both i n Canada and, to some ex t e n t , i n s m a l l A f r i c a n communities. J l i t h t h i s background I f e e l q u a l i f i e d t o add a few comments on t h i s t o p i c . A f t e r the examination of over 300 w i l d unqulate c a r c a s s e s and t a l k i n g with s e v e r a l o t h e r r e s e a r c h v e t e r i n a r i a n s i n t h i s f i e l d (fi. Sachs, H-Jakob, P. Hummel, B. , Schieman, H. Woodford, V. De Vos, H-Ebedes, H. Mustafa) , I can say t h a t most wild animal p o p u l a t i o n s have very few i n f e c t i o n s which are of concern t o meat i n s p e c t i o n p e r s o n n e l . The f a c t i s th a t the f u r t h e r the animals are from human s e t t l e m e n t s and domestic animals, the fewer are t h e i r i n f e c t i o n s . And of these, very few are of importance to meat i n s p e c t i o n . 196 In a d d i t i o n t o t h i s p o i n t i s the f a c t t h a t most people engaged i n s l a u g h t e r i n g animals can g u i t e r e a d i l y d i s t i n g u i s h between a c c e p t a b l e and unacceptable c a r c a s s e s , and between normal and abnormal t i s s u e . I t i s because of t h i s f a c t t h a t the method o f meat supply i n most A f r i c a n communities, which c u s t o m a r i l y i n v o l v e s a head of a f a m i l y s l a u g h t e r i n g an animal which they have e i t h e r r a i s e d o r bought a l i v e , works q u i t e w e l l , i n s p i t e of t h e f a c t t h a t these animals are more l i k e l y t o have i n f e c t i o n s of meat i n s p e c t i o n concern than w i l d animals. I f the cropping i s not done by a member of the f a m i l y , there i s the problem of en s u r i n g t h a t the cropper*s judgements about the a c c e p t a b i l i t y o£ the meat w i l l be r e s p o n s i b l e . Perhaps the b e s t way o f guaranteeing t h a t h i s d e c i s i o n w i l l be a r e s p o n s i b l e one, i s f o r him to be a member of the community he se r v e s . Then h i s r e p u t a t i o n and cropping p r i v i l e g e s w i l l depend on the q u a l i t y o f the meat he s u p p l i e s . Regarding the judgement of s u i t a b i l i t y of c a r c a s s e s f o r ineat^ I have only a few comments t o make. Anthrax i s a d i s e a s e of meat i n s p e c t i o n importance i n wild and domestic animal p o p u l a t i o n s throughout A f r i c a . Although the o l d A f r i c a n s a y i n g t h a t the animal i s a c c e p t a b l e f o r meat i f t h e r e i s l o t s of b r i g h t red bloo d when i t s t h r o a t i s c u t i s a f a i r l y good r u l e of thumb t o safeguard a g a i n s t t h i s d i s e a s e ; when a p p l i e d t o weak or s i c k animals, i t can be a dangerous r u l e . T h i s i s because I have seen many cases i n which an absence of c o p i o u s g u a n t i t i e s of bipod from a c u t throat have been e x p l a i n e d on the b a s i s o f othe r , very l i k e l y reasons which may a l s o be present when an animal i s s i c k of anthrax. T h e r e f o r e , I would s t r e s s the 197 importance i n game cropping of only s e l e c t i n g a c t i v e and a l e r t animals f o r s l a u g h t e r , and not s t r a g g l e r s . Furthermore, s t u d i e s have shown th a t animals i n anthrax areas are probably c a r r i e r s of the i n f e c t i o n i n the r e t r o p h a r y n g e a l lymph nodes. For t h i s reason I would c o n s i d e r the c a r e f u l removal and d i s p o s a l of these lymph nodes s h o r t l y a f t e r death a d e s i r a b l e p r a c t i c e . One t h a t i s u s u a l l y employed anyway. F i n a l l y , I would l i k e t o s t r e s s the importance o f cooking thoroughly a l l organ meats such as l i v e r , h e a r t , and kidney of both w i l d and domestic animals because of the p o s s i b i l i t y of i n g e s t i n g pentastomid l a r v a e and a c g u i r i n g the halzoun and marrara syndrome. 1 9 8 L i t e r a t u r e C i t e d Anderson, E.C., J . Anderson, H.J- Doughty, and S. Drevmo. 1 9 7 5 . The p a t h o g e n i c i t y of bovine s t r a i n s of foot-and-mouth d i s e a s e v i r u s f o r impala and wi l d e b e e s t . J . H i l d l . 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Zoology
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The role of anthrax in the population biology of wildebeest in the Selous Game Reserve
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