886 MICROBIOLOGY OF DISEASES OF MAN AND DOMESTIC ANIMALS 



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

 It is probable that these principles will 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 or animals 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. By experimental inoculation, and by the examination of 

 animals naturally infected, it has been shown that wild and domestic 

 animals of many species may be infected with the trypanosomes which 

 are usually the cause of sleeping sickness. Some animals are killed by 

 the infection. All of the larger animals resist the infection for very 

 considerable periods and it is possible that many of them are tolerant 

 to the infection. This is especially true of the larger ruminants. 

 Therefore, antelope, buffalo game should be driven away or de- 

 stroyed in the neighborhood of human habitation in order to remove a 

 dangerous reservoir of infection. 



HUMAN TRYPANOSOMIASIS OF SOUTH AMERICA 



Trypanosoma cruzi Chagas, 1909 



This disease is caused by Trypanosoma cruzi (Schizotrypanum cruzi} 

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

 It has been foU^nd only in Brazil. 



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

 cell. It multiplies, in the tissue cells of muscles and organs, by losing its locomotory 

 apparatus and forming Leishmania-like bodies which multiply by repeated divisions 

 and develop into new trypanosomes. These young parasites leave the destroyed 

 tissue cell where they were produced and enter the blood vessels. 



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

 by wasting, cedema, 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 

 Lamus resemble those of a bed bug. 



