HOW TO AVOID SLEEPING SICKNESS 39 



T. rhodesiense in its human host follows the same 

 cycle as T. gambiense, and produces latent bodies 

 resembling those of the older-investigated parasite. 

 Further work by Kinghorn and Yorke in Africa has 

 shown definitely that certain big game antelopes, 

 bushbuck, etc. harbour T. rhodesiense without them- 

 selves being affected by it. But flies feeding on such 

 big game get infected and are capable of transmitting 

 the trypanosome to man. It may be mentioned that 

 earlier laboratory experiments had been made to 

 determine whether tsetse flies other than G. palpalis 

 can transmit T. gambiense, and the work of Taute 

 has shown that G. morsitans a widespread tsetse 

 can act as a carrier, while that of P. H. Ross has 

 in a single instance inculpated G. fusca. 



The preventive methods advocated in connexion 

 with the spread of sleeping sickness may be 

 briefly summarized. Supervision of the journeys 

 of travellers from infected districts should be strict, 

 particularly where natives, who are known to be 

 followed by tsetses, are concerned. Persons suffer- 

 ing from sleeping sickness should be removed from 

 the belts frequented by the flies to places where they 

 are not liable to be attacked and so become new 

 sources of infection. Villages in the fly-belt, where 

 necessary, should be destroyed, and their inhabitants 

 removed under supervision to fresh quarters, a 

 matter of some difficulty. It is also important that 

 big game, which act as reservoirs of disease, should 

 be kept down to a much greater extent than is the 

 case at present. 



For the better protection of Europeans, their 



