570 FAMILY: TRYPANOSOMID^ 



but no statement is made as to whether the rabbits died of their infections 

 or not. In a further series of experiments, Cross (1923) confirms his 

 original findings. The ticks transmitted the trypanosome seventeen days 

 and one month after feeding on an infected animal. He thinks it probable 

 that a cyclic development occurs in the ticks. He has also transmitted 

 the trypanosome mechanically by means of Tabanus albimedius, when the 

 feeds on the infected and uninfected animals followed one another imme- 

 diately., Yorke and Macfie (1924) report that they received about 200 

 0. crossi from Cross in India. Though the ticks had been fed on an 

 infected dog in India, and after their arrival in Liverpool were found to 

 contain well preserved, though motionless, trypanosomes, they failed to 

 infect rabbits on which they were fed. The writer also failed to infect 

 rabbits and rats with a batch of similar ticks received from Cross. 

 Though Singh (1925) states that he has confirmed the observations of 

 Cross and Patel, the subject is one which requires further investigation. 



Reservoir. — The question of a reservoir host for Trypanosotna evansi 

 has been frequently raised. Camels, in which the disease pursues a 

 chronic course, must act in this way, as also the buffalo, which may carry 

 the trypanosome without suffering to any great extent. Baldry (1910) 

 expressed the opinion that the pig was a source of infection for other 

 animals, and he showed that it was susceptible to inoculation. 



Treatment. — As regards treatment, the best results have been obtained 

 by the use of atoxyl subcutaneously and arsenious acid by the mouth, 

 as recommended by Holmes (1910) in India. Maya (1912) had good 

 results with this treatment in Mauritius. Thiroux and Teppaz (1910) 

 report favourably on the action of orpiment by the mouth associated with 

 atoxyl or tartar emetic injections, while Cross (1920, 1920a) found that 

 tartar emetic intravenously gave promise of success. 



Other Trypanosomes of the Trypanosoma evansi Type. 

 Forms in Asia and Africa. 



Trypanosoma evansi var. mborii Laveran, 1911. — A disease of drome- 

 daries known as mbori was first described by Cazalbou (1903) in the 

 French Sudan. It occurs in the districts of the Niger and Senegal Rivers, 

 and was first noted by its discoverer at Timbuctoo. It affects horses as 

 well as dromedaries, and produces a disease similar to surra. Laveran 

 (1904c) considered the trypanosome which causes the disease to be a variety 

 of T. evansi, and he (1911) named it T. evansi var. mborii. It is inoculable 

 into the same animals as T. evansi, but is less virulent. Morphologicallv 

 it is indistinguishable from the trypanosome of surra. 



A trypanosome of the same type has been recorded as producing a 



