MICROBIAL DISEASES. OF MAN AND DOMESTIC ANIMALS 83 1 



order to destroy them at all stages of their development, the following 

 general rules are now observed in the treatment of trypanosomiasis. 

 The drugs employed should be alternated, and they should be given 

 as early in the disease as possible, and in as large doses as possible. 

 It is probable that these principles wiU be found to be of value in the 

 treatment of other diseases caused by protozoa. 



The prevention of the disease depends upon the avoidance of the 

 water's edge, where Glossina palpalis exists, and of the proximity of 

 persons infected by trypanosomiasis. The most usually successful way 

 of recognizing infected persons is by the discovery of trypanosomes in 

 the fluid aspirated from their enlarged lymphatic glands. 



Human Trypanosomiasis of South America 

 Trypanosoma cruzi — Chagas, 1909 



This disease is caused by Trpyanosoma cruzi {Endotrypanum cruzi) 

 and is transmitted by the bites of a reduviid insect, Conorrhinus megistus. 

 It has only been fotijnd in Brazil. 



Trypanosoma cruzi may be either free in the blood plasma or lie within a red 

 cell. It multiplies, in the organs, by losing its locomotory apparatus and forming 

 a sphere which divides into eight portions: a new trypanosome develops from each 

 portion. 



The disease is a chronic one, characterized by irregular temperature, 

 by wasting, oedema, and enlargement of the spleen and lymphatic 

 glands. It occurs chiefly in young children and is often fatal. It may 

 be prevented by avoiding the insect which transmits it — the habits of 

 the Conorrhinus resemble those of a bed bug. 



Trypanosomiases gi- Animals 



Several diseases, of great economic importance, which affect 

 domestic animals, are caused by trypanosomes. The following are the 

 most important. Tsetse-fly disease, or nagana, of Southern Africa, is 

 caused by Trypanosoma brucei (Plimmer and Bradford) and it is trans- 

 mitted by the Tsetse fly, Glossina morsitans; it affects all domestic 

 animals. 



In South America, Mai de caderas, a disease of horses, is caused by 



