26 



Sir D. Bruce and others. Trypanosome 



Hcematopota, or other biting flies may act as mechanical carriers. The 

 evidence that Stomoxys plays a similar rdle is unsatisfactory. 



Conclusions. 



1. The Mvera Cattle strain, the Wild-game strain and the Wild 

 G. morsitans strain belong to the same species of trypanosome, T. pecorum. 



2. T. pecorum, Nyasaland, is identical with the species found and described 

 in Uganda. 



3. It is an important disease of domestic animals in ISTyasaland, being 

 destructive to donkeys, oxen, goats, pigs, and dogs. 



4. Its carrier in this district is G. morsitans, about 2 per cent, probably of 

 the local wild flies being naturally infected with T. pecorum. 



5. Its reservoir is the wild game inhabiting " fly-country," 14'4 per cent, of 

 which were found to be infected with this trypanosome. It is hardly to be 

 doubted that 100 per cent, are, or have been, infected. 



6. It is recommended that if infected animals are found in a herd they 

 should be destroyed or segregated, as there is a danger of biting flies other 

 than the tsetse spreading the disease in the herd by mechanical transmission. 



Morphology of Various Strains of the Trypanosome causing 

 Disease in Man in Nyasaland. — The Mzimba Strain. 



By Surgeon-General Sir David Bruce, C.B., F.R.S., A.M.S. ; Majors David 

 Harvey and A. E. Hamerton, D.S.O., B.A.M.C. ; and Lady Bruce, 

 R.R.C. 



(Scientific Commission of the Royal Society, Nyasaland, 1913.) 

 (Received May 5 —Read May 29, 1913.) 

 [Plates 1-3.] 



Introduction. 



Up to the present time it has usually been considered that almost all the 

 cases of Human trypanosome disease in man in Nyasaland have been 

 confined to a small area. This, the so-called Sleeping- Sickness District, has 

 been described in a former paper,* but it may be repeated here that it is the 

 part of the " fly-country " lying along the western shore of Lake Nyasa, 



* ' Eoy. Soc. Proc.,' B, vol. 86, p. 274. 



