278 



PROTOZOOLOGY 



camels, cattle, swine, dogs, etc., which terminates in the death of 

 the host animal in from two weeks to a few months; wild animals 

 are equally susceptible; the disease occurs, of course, only in the 

 region in Africa where the tsetse flies live. 



T. iheileri Laveran (Fig. 124, h). Large trypanosome which oc- 

 curs in blood of cattle; sharply pointed at both ends; 60-7 Oju long; 

 myonemes are well developed, 



T. americanum Crawley. In American cattle; probably identical 

 with T. theileri; transmitted from cattle to cattle by tabanid flies. 



Fig. 124. a, Trypanosoma hrucei; b. T. theileri; c, T. melophagium ; 

 d, T. evansi; e, T. equinum; f, T. equiperdum; g, T. lewisi; all X1330 

 (several authors). 



T. melophagium (Flu) (Fig. 124, c). A trypanosome of the sheep; 

 50-60m long with attenuated ends; transmitted by Melophagus 

 ovinus. 



T. evansi (Steel) (Fig. 124, d). In horses, mules, donkeys, cattle, 

 dogs, camels, elephants, etc. ; infection in horses seems to be usually 

 fatal and known as "surra"; about 25^* long; monomorphic; trans- 

 mitted by tabanid flies; widely distributed. 



T. equinum Vages (Fig. 124, e). In horses in South America, caus- 

 ing an acute disease known as "mal de Caderas"; other domestic 

 animals do not suffer as much as do horses; 20-25^ long; without 

 blepharoplast. 



T. equiperdum Doflein (Fig. 124, /). In horses and donke,ys; 

 causes "dourine," a chronic disease; widely distributed; 25-30/Lt 

 long; no intermediate host; transmission takes place directly from 

 host to host during sexual act. 



