1910.] Diseases of Domestic Animals in Uganda. 475 



Trypanosoma dimorphon, Trypanosoma congolcnsc, the Uganda, Zanzibar, 

 Chai-Chai, Zambesi, Zuliiland, and Rhodesian strains is identical ; these 

 trypanosomes affect the same important domestic animals ; the carrier is 

 probably or may be the same, though this is not known, and therefore these 

 various forms should, for the present, be grouped under one name ; and for 

 certain reasons given above we propose the name Trypanosoma pecorum for 

 this group. 



Disease set up in Cattle hy Trypanosoma pecorum. 



It is unnecessary in this paper to describe in detail the symptoms which 

 can be noted during life, or the pathological changes set up in the organs of 

 cattle by this trypanosome. It will be sufficient to say that the main 

 symptoms are emaciation, ancemia, and progressive weakness, and that the 

 principal post-mortem appearances are those due to anaemia. 



Incubation. — As is probably true of most trypanosome diseases in 

 susceptible animals, the period of time which elapses between the infection 

 of the animal and the appearance of the trypanosomes in sufficient numbers 

 in the peripheral blood to be seen by the microscope, is a short one : in this 

 case, an average of 6'7 days. 



Duration. — Of the course and duration of this disease in cattle little, 

 unfortunately, is known. Most of the cattle which came under observation 

 at the laboratory of the Commission at Mpumu were already sick when they 

 arrived, and it was, as a rule, impossible to know when they had been 

 infected. By referring to the table it will be seen that 22 naturally-infected 

 cattle were under observation. Four of them lived, on an average, nine 

 months. Of these four, one, treated with arsenic, was still alive and 

 apparently healthy in December, 1909, one was killed, one had been treated 

 with lithium antimonyl tartrate, and one died without treatment at the end 

 of 313 days. It is therefore impossible to say from the insufficient data at 

 our disposal whether spontaneous cure ever takes place in this disease in 

 cattle. 



When we turn to the cases of cattle which were inoculated on the hill, 

 and were therefore under observation from the beginning, we are struck by 

 the rapid course of tlie disease. One animal certainly lived 287 days, but 

 the remainder died, on an average, in 26 days from the date of infection. 

 Most of these oxen were inoculated with a strain of this trypanosome which 

 had caused a rapidly fatal epidemic among a herd of milch cattle belonging 

 to Mr. "Walsh, at Kabula Muliro. In the short space of one month 24 of 

 Mr. Walsh's cattle died, and in two months 34 had died out of a herd of 

 about 300 head. 



