!090 PATHOGENIC PROTOZOA 



after inoculation but without sickening. In no animal, however, is 

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

 man. 



Trypanosoma rhodesiense. This species was established by 

 Stephens and Fantham. 6 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 

 less amenable to treatment; the trypanosome is also more virulent 

 for animals and may be differentiated from gambiense on its 

 morphology. As both parasites are found in the antelope, the prophy- 

 laxis is the same. Bruce 7 is of the opinion that rhodesiense and 

 brucci are identical, but Taute and Huber,* by inoculating themselves 

 and 129 natives with the blood of naturally infected animals with 

 out reproducing the disease, seem to have shown that the parasites 

 are not identical. 



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. Better results are obtained when 

 atoxyl and tartar emetic are both used and also when the treatments 

 are repeated every six months. The successful treatment of an intract- 

 able case of gambiense infection with stibenyl (the sodium salt of 

 p-acetylaminophenyl-stibinic-acid) has been reported by Manson-Bahr 



'Stephens and Fantham, Proc. Eoy. Soc., 1910, Ser. B., Ixxxiii, 28. 



1 Bruce, Bull. Trop. Dis., 1916, vii, 68. 



* Taute, M., and Uulxr, /'., Abstracted in. Trouieal Diseases. Bull. London, 1930. 



