462 FAMILY: TRYPANOSOMIDiE 



Low and Manson-Bahr (1923) have also obtained apparent cures in a 

 large percentage of human cases treated by them. It appears that the 

 drug gives a fair promise of cure only in the cases which have no involve- 

 ment of the central nervous system. As regards the action of the drug 

 on trypanosomiasis of domestic animals, Kleine and Fischer (1923) find 

 that its action is less marked than in the case of human beings, while in 

 the animals T. brucei is more responsive than T. vivax or the closely allied 

 T. cajjroe. It appears that the more nearly the infected host resembles the 

 natural reservoir, the less active is the drug. Thus, T. brucei is more 

 readily eradicated from man than from cattle, for the latter are more 

 closely related to the buffalo, which is one of the natural reservoirs of this 

 trypanosome. 



Another drug which has a marked trypanocidal action in the case of 

 experimentally infected laboratory animals is tryparsamide, the sodium 

 salt of N. phenylglycineamide-j9-arsonic acid. Its action in sleeping 

 sickness has been the subject of an investigation by Pearce (1921) in the 

 Belgian Congo. Van den Branden and Van Hoof (1923) have followed up 

 some of the cases treated by Pearce, and report that a cure can be effected 

 in 100 per cent, of early cases of human trypanosomiasis in the Belgian 

 Congo when the cerebro-spinal fluid is still normal, and that in a large 

 percentage of more advanced cases a similarly successful result can be 

 obtained. 



In the treatment of human beings suffering from trypanosomiasis, the 

 drugs hitherto most usually employed are atoxyl or soamin and tartar 

 emetic. Injections of one or both of these must be continued over long 

 periods, and cure may be effected in a certain number of cases. It must be 

 remembered, however, that some cases tend towards a natural recovery, 

 and appear to respond very well to treatment, while others get progressively 

 worse in spite of the remedies used. On this account, great caution has 

 to be exercised in ascribing good results to any particular line of treatment, 

 while a cure cannot be said to have certainly taken place unless there 

 have been no signs of the disease for some years. 



In the treatment of trypanosomiasis of domestic animals, the above- 

 mentioned compounds, as well as liquor arsenicalis, have been tried with 

 varying success. Tartar emetic administered intravenously seems to give 

 the best results. Hornby (1919), working in Rhodesia, noted that horses 

 and other equidse were more liable to infection with T. brucei than with 

 T. congolense and T. vivax, while the reverse was the case for cattle. 

 Hornby found that tartar emetic had little effect in saving horses infected 

 with T. brucei, but was of great value for cattle harbouring T. congolense 

 or T. vivax. He has informed the writer that as many as 80 per cent, of 

 the cattle may be saved by the use of this drug if treatment is commenced 



