XVI] GLOSSINA PALLIDIPES 273 



G. PALLIDIPES and Disease. 



As mentioned below Austen has shewn that it is almost 

 certain that Bruce, in his Zululand experiments on the trans- 

 mission of T. brucei, employed G. pallidipes and not G. morsitans. 



In addition, Dr P. H. Ross has found G. pallidipes in British 

 East Africa naturally infected with a trypanosome that seems 

 to belong to the dimorphon group. In one case a dog naturally 

 infected with trypanosomes on Mombasa Island, is stated to 

 have been almost certainly infected by the bites of G. pallidipes 

 on the island. 



In another case wild G. pallidipes from the neighbourhood 

 of Kibwezi (British East Africa) were fed on a healthy monkey. 

 In all " 209 flies were fed between July 15 and December 10. 

 The animal died on January n, and it was only after death 

 that trypanosomes were found. Inoculation of blood from 

 the dead monkey into a fresh monkey resulted in infection, 

 but inoculation of a dog at the same time failed. In this case 

 infection was suspected nine days after feeding began, but 

 repeated examinations of the blood during five months were 

 always negative. The monkey became very thin, and had all 

 the appearance of a trypanosome-infected monkey, and the 

 temperature chart was also very suggestive of trypanosomiasis. 

 The trypanosomes found in this animal were 17-18 microns 

 in length, including a short, free flagellum, and had rather a 

 blunt posterior end." 



In further experiments with this trypanosome, goats and 

 sheep were found to be immune against infection and two 

 monkeys that became infected were alive after five months 

 and a year respectively. With regard to the immunity of 

 goats and sheep, the author notes that the Wakamba natives 

 move their cattle to the hills in August when G. pallidipes is 

 about to reappear, stating that the fly would kill them, but 

 they do not move their sheep and goats. 



From these observations it is evident that G. pallidipes is 

 capable of transmitting other infections in addition to T. brucei, 

 but up to the present there is no very precise information as to the 

 manner in which it is effected. Presumably the transmission is 

 usually indirect, as in the case of most other species of tsetse-flies. 



H.B.F. 18 



