RESERVOIRS OF TRYPANOSOMES 27 



caught in the Sleeping Sickness area, and it was found 

 that this could be readily done ; waterbuck, bushbuck 

 and reedbuck in captivity could all be made reservoirs 

 of the Trypanosome without any harm to themselves, 

 and could continue to infect bred flies fed upon them for 

 more than twelve months after they had been artificially 

 infected.'^ Finally, in March 1912, Dr. Duke announced 

 that the antelope known to the natives as " Enjobe " 

 was a natural reservoir of Trypanosoma gambiense, and 

 the chain was thus completed. ^ 



It had seemed for some time probable that there must 

 be a natural host, although it had not been found. Four 

 years and a half after the natives had been removed from 

 the islands the fly there was still infective, and it was 

 impossible to suppose, that the same flies were still alive 

 that had been the cause of the epidemic. With one 

 exception the animals and birds and reptiles within 

 reach of the fly had been sufficiently examined to make 

 it almost certain that they were not incriminated, and 

 the one large antelope living on the islands was yet to be 

 excluded. Accordingly, in the latter part of 1911 Dr. 

 Duke came over to my camp on Damba Island to shoot 

 and investigate the very abundant " Enjobe " there. 

 This antelope, the Situtunga {Tragelaphus speJcei), lives in 

 most intimate association with the fly among the shaded 

 forests at the water side. 



A number were shot and their blood was injected 

 into monkeys, one of which, injected on November 5th 

 and 6th, showed Trypanosomes in its blood on the 18th. 

 It was taken to the laboratory on the mainland and the 

 nature of the Trypanosome investigated in every possible 

 way, and Dr. Duke considered that there was no doubt 

 that he had at last found the source from which the 



* Reports of the Sleeping Sickness Commission, No. XI, p. 71, etc. 

 ^ Ibid. No. XII, p. 117 et seq. See also article by Duke in BiHtish 

 Medical Journal, 1914, February 7th. 



