DISEASES DUE TO ANIMAL PARASITES 191 



Morbid Physiology. There are general functional 

 disturbances. The condition of the bowel causes diar- 

 rhea and consequent weakness. 



TRYPANOSOMIASIS (SLEEPING-SICKNESS) 



Definition. A chronic disorder due to the Trypano- 

 soma gambiense, characterized by fever, lassitude, 

 weakness, and often protracted lethargy. 



Etiology. This disease is prevalent in West Africa 

 and is due to the trypanosome. Infection occurs by 

 the bite of a fly, the Glossina palpalis. This fly lives 

 on the bushes and weeds along the shores of streams 

 and lakes. 



Morbid Anatomy. The parasite is found in the cere- 

 brospinal fluid and blood. In the early stage of the dis- 

 ease the lymphatic glands are enlarged and the parasite 

 is found in them. 



Morbid Physiology. The manner in which the 

 parasite produces its characteristic disturbances 

 fever, rapid pulse, dulling of the mind, tremors, and, 

 finally, subnormal temperature and coma has not yet 

 been determined. 



MALARIAL FEVER (AGUE) 



Definition. An infectious disease caused by the 

 Plasmodium malariae, characterized by periodic occur- 

 rences of chill, fever, and sweating. 



Etiology. The disease is contracted through the bite 



