95 



Tragelaphus scriptus, and Strepsiceros kudu (koodoo). At Ngoa, also 

 in Northern Rhodesia, out of 124 mammals, trypanosomes were 

 detected in 21. x 



In Nyasaland, the plain extending inland from the western shore of 

 Lake Nyasa is for the most part " covered with thorn scrub," which is 

 " the home of the Tsetse-fly [G. morsitans] and also of numerous wild 

 animals." In studying the trypanosomes found in the blood of wild 

 animals living in this area, the members of the Sleeping Sickness 

 Commission of the Royal Society (Surgeon-General Sir David Bruce, 

 C.B., F.R.S., A. M.S. ; Majors David Harvey and A. E. Hamerton, 

 D.S.O., R.A.M.C. ; Dr. J. B. Davey, Nyasaland Medical Staff ; and 

 Lady Bruce, R.R.C.) adopted the following procedure. When an 

 animal was shot in the fly-country by one of the Commission, a specimen 

 of the blood was " taken in a bottle containing citrate of soda solution," 

 and despatched by a motor-cyclist to the camp, where it was " at once 

 injected into a goat, a monkey, and a dog." Thick and thin films of 

 the blood were also " spread on glass slides for microscopical exami- 

 nation." In this way, among "180 wild animals shot in the fly-area 

 adjoining the Commission's camp at Kasu .... 57 were found 

 to harbour pathogenic trypanosomes 31-7 per cent." 2 The animals 

 proved to be infected were the waterbuck, hartebeeste, reedbuck, 

 duiker, koodoo, eland, bushbuck, oribi, buffalo, hyaena, and wart-hog. 

 In the opinion of the Sleeping Sickness Commission, in the fly-district 

 in question the first four are " dangerous neighbours to man ; the 

 eland, koodoo, bushbuck and buffalo to cattle, goats and sheep." It 

 is also pointed out that " the wart-hog is the only animal which 

 harbours T. simiae, the lightning destroyer of the domestic pig." 



" We see, then," writes Dr. Bouet (11), " the important part played by 

 the large antelopes and other big game in the propagation of trypano- 

 somiasis. These animals constitute the reservoir of virus whence 

 Tsetse-flies derive the trypanosomes, the development of which takes 

 place in the alimentary canals of their insect hosts. Trypanosomes 

 have no influence upon big game, and do not seem to affect their health 

 in any way." 



Several proofs, obtained chiefly in French West Africa, of the fact 

 that big game is the sole reservoir of trypanosome virus are adduced 

 by Dr. Bouet, who adds that, " without wishing for the total destruction 

 of our African fauna, it is desirable that the restrictive measures that 

 must be taken for the protection of the game should not be too pro- 

 hibitive, since there can be no doubt that, from the day when the 

 native is prevented from hunting or forced to pay a tax for the right 

 to do so, there will be a recrudescence of trypanosomiasis in consequence 

 of the swarming of game." 



Another great argument of the partisans of the destruction, or at 

 least the driving back of the big game in Central Africa is based upon 

 the fact that, as a sequel to the rinderpest that ravaged the Transvaal 

 and Rhodesia some five and twenty years ago, much of the big game, 

 and with it the Tsetse-flies in large measure, disappeared from those 

 regions. It may be urged, however, by way of objection to this, that 



1 Out of 256 monkeys examined not a single one was infected, which, in the 

 opinion of Kinghorn and Yorke, is due to the fact that these animals catch 

 Tsetse-flies before the latter have time to bite them. 



2 " The species of trypanosomes found are T. brucei vel rhodesiense 7-8 per cent., 

 T. pecorum 14-4, T. simiae 1-7, T. caprae 11-1, and T. ingens 1-7." The last- 

 mentioned species is not at present known to be pathogenic either to domestic 

 animals or to man. 



