754 PATHOGENIC PROTOZOA 



it possible to reproduce the sleeping sickness stage as it occurs in 

 man. 



Diagnosis. When the disease is well developed in an endemic 

 area, the diagnosis is easily made. During the early stages the exami- 

 nation of the cerebro-spinal fluid, puncture fluid from the lymph nodes 

 and the peripheral blood may all show the trypanosome; since the 

 parasites are scarce the use of the thick film method of Ross may be 

 necessary. When direct examination is unsuccessful, enrichment in 

 the blood of susceptible animals, rats and mice will establish the 

 diagnosis. 



Treatment. Treatment is based upon the observation of Bruce 

 and Lingard, that arsenious acid is trypanocidal. The best results 

 have been obtained with atoxyl, in half gram doses, repeated at inter- 

 vals of ten days or more for not less than four months. Light cases; 

 become trypanosome free and are apparently cured, yet many relapse 

 on cessation of treatment. Well marked cases may show improvement, 

 yet ultimately grow worse and die. Other arsenical preparations have 

 been used but none are entirely successful. Salvarsan drives the 

 parasite from the peripheral blood but not from the cerebro-spinal 

 fluid. The prognosis is unfavorable. 



Prophylaxis. Prophylaxis is quite complicated and is carried out 

 along several different lines. Infected fly belts are depopulated, the 

 inhabitants being removed to a fly-free district where they may be 

 treated at hospital stations. The fly breeding may be greatly 

 diminished by clearing off the forest and brush, especially along the 

 river courses, since the glossina needs abundant moisture for its propa- 

 gation. Since the fly bites only during the day, all traveling in 

 infected districts is best done at night. 



As it is recognized that the antelope is the permanent reservoir for 

 Trypanosoma gambiense, the obvious remedy is its extermination. 



Trypanosoma rhodesiense. This parasite was established by 

 Stephens and Fantham. 1 It is transmitted by the Glossina morsitans, 

 a fly which is widespread over large tracts of country, independently 

 of the presence of water. It is becoming generally recognized that 

 there are two forms of sleeping sickness, one of which is caused by 

 this trypanosome. This form of the disease is more acute and is 

 unaffected by treatment; the trypanosome is also more virulent for 

 animals and may be differentiated from gambiense on its morphology. 



1 Stephens and Fantham, Proc. Roy. Soc., 1910, Ser. B., Ixxxiii, 28. 



