TRYPANOSOMA GAMBIENSE 539 



in infecting sheep and goats in the same manner. Prolonged search 

 amongst antelope by Bruce, Kleine and Fischer, Duke and Fraser, and 

 other workers for a reservoir host for T. gaynhiense did not meet with any 

 success, except in the case of the sitatunga noted above. Koch, Beck, 

 and Kleine (1909), and Bruce et al. (1911e) reported having found monkeys 

 naturally infected with trypanosomes resembling T. gambiense. Trypano- 

 somes which were possibly T. gambiense were seen by Kleine and Eckard 

 (1913) in a cow, a sheep, and a goat in Tanganyika, by Duke (1913a) in a 

 buli'alo and a hyena in Western Uganda, by Yorke and Blacklock (1915) 

 in a cow in Sierra Leone, and by Simpson (1918) in a reed buck in the 

 Gold Coast. In none of these cases can it be taken for granted that the 

 trypanosome was certainly T. gambiense. Unless studied in small labora- 

 tory animals, it is impossible to distinguish T. gambiense from T. brucei, 

 and in most of these instances of supposed infection with T. gambiense this 

 was not done. Even Duke's observation (1912a, 1912c) on the sitatungas, 

 which has been generally accepted, is open to doubt, for, reinvestigating 

 these animals (1921), he found that the trypanosomes with which they 

 were naturally infected produced posterior nuclear forms when injected 

 into guinea-pigs, and were more virulent than those jDreviously isolated. 

 He concludes that T. gambiense, by long residence in the sitatunga, has re- 

 verted to the T. brucei type, but at the same time admits that during the 

 earlier investigations the significance of posterior nuclear forms was not 

 realized, so that they were not specially looked for, and may have been 

 neglected. It would seem, therefore, that search for a reservoir host for 

 T. gambiense has shown that occasionally domestic animals living in associa- 

 tion with human beings amongst whom the disease occurs may acquire an 

 infection, but there is little or no evidence to incriminate the wild game as 

 reservoirs of this trypanosome. There does not appear to be such a close 

 connection between T. gambiense and the wild fauna of Africa as in the case 

 of T. brucei. Probably, therefore, man himself, and sometimes the domestic 

 animals near him, are most usually the sources from which G. palpalis 

 derives its infection. T. gambiense, which undoubtedly originated from a 

 trypanosome of animals (probably T. brucei) in the first place, has now 

 become adapted to man to such an extent that there is little tendency for 

 it to infect the game. In this respect it stands in marked contrast to the 

 human strain of T. brucei {T. rhodesiense). 



Trypanosoma brucei Plimmer and Bradford, 1899. — Synonyms: T. suis 

 Ochmann 1905; Trypanozoon brucei {Lxihe, 1906); T. suis {L,iihc. 1906); Trypanosoma 

 pecaudi Laveran, 1907; T. togolense Mesnil and Brimont. 1909; T. elephantis Bruce 

 et al., 1909; T. rhodesiense Stephens and Fantham, 1910; T. ancepis Bruce et al., 1914 

 T. Uganda; Stephens and Blacklock, 1913; Castellanella brucei (Chalmers, 1918) 

 C. rhodesiense (Chalmers. 1918); T. multiforme Kinghorn and Yorke, 1913 (?) 

 T. cqui Blacklock and Yorke, 1914 ('?); T. dulcei Knuth and du Toit, 1921. 



