136 DISEASES DUE TO PROTOZOA 



Development. 



At first this takes place in the gut of the tsetse, then in the labial 

 cavity of the proboscis, later in the salivary duct, but, be it noted, not 

 in the salivary gland. In the salivary duct it reverts to its original 

 form and becomes infective. 



The cycle requires nineteen to fifty-three days for the development 

 of infectivity. The intestinal forms cannot be distinguished from other 

 intestinal developmental forms of pathogenic trypanosomes. 



Thousands of infective forms can be obtained by a biting fly 

 attempting to bite one's finger through a watch glass, when the saliva 

 will reveal them. 



Reservoir. 



I4'4 per cent, of animals examined were infected. These were : — 



Eland, 60 per cent. ; Koodoo, 66 per cent. ; Bush buck, 70 per cent. ; 

 Bufifalo, 22 per cent. 



T. brucei were not found in any of the animals examined. 



T. simian. 



This is very virulent towards monkeys and domestic pigs, killing 

 them in a few days. It is harmless to oxen, antelopes, dogs and 

 smaller experimental animals. It affects goats and sheep. 



It is like T. pecorum, in that its virulence soon becomes modified. 



The warthog is the onlv member of wild game yet found to harbour 

 it. 10 per cent, of the thirtv examined were found to be infected. 



The trypanosome is 14-24 jit long. 



The long undulating body frequently extends in a straight line. 



The cytoplasm is clear. 



It is very fatal to domestic pigs, killing them off in 5'3 days. 



It kills monkeys in io*8 days, goats and sheep in 46*6 days. 



3'4 per 1,000 flies were infective after experiments. 

 Its development in the tsetse is as that of T. pecorum. 



Group (C). 



The size only separates the species of this group. 



T. vivax. 



It causes the most important cattle disease in Uganda. 



It is widely distributed in Central Africa. It has been reported 

 from the Soudan, Senegal and Northern Rhodesia. 



Its marked activity during life distinguishes it. 



It only affects horses, cattle, goats and sheep. Other animals are 

 refractory. 



It has been found in the bush buck. 



Tsetse flies were found infected by it. 



T. uniforme. 



As above, but smaller. 



