so:me notes ox the trypanosomiases of 



RHODESL\. 



By Ll!:\vellvx Edgar W'h.liams Bevax, ALR.CA'.S. 



When selecting a subject for a paper to place before this. 

 Association, I felt that a few notes on the t'"ypanosoaiiases of 

 Rhodesia might prove of interest, inasmuch as so many branches 

 of science are concerned in the elucidation of the varied prob- 

 lems presented by these maladies. But it was obviously impos- 

 sible in a paper such as this to deal adequately with a study of 

 such magnitude, and I have had to limit myself to a brief review 

 of the subject, emphasising those features which particularly 

 relate to this countr}-, or have been the subject of personal 

 observation and research. 



The term " trypanosomiasis " includes certain diseases of 

 man and the lower animals caused by the invasion of the blood- 

 stream by minute flagellated i:)rotozoa called trypanosomes 

 [TpvTravoi', a borer, o-ojyu-i, body) from the characteristic 

 movements when viewed under the microscope. 



The manner in which these parasites are transmitted from 

 sick to healthy animals varies, but, as far as the trypanosomiases 

 of this country arc concerned, the most common method of trans- 

 nn'ssion is by the bite of the so-called " tsetse fly," a fact which 

 has been long recognised and has given rise to the name " fly 

 disease." which is popularly applied to the trypanosomiases of 

 animals. It is impossible to determine when these infefctions 

 were first introduced into Rhodesia, and whence they came, but 

 the earhest of modern explorers of this country, Livingstone, 

 Kirk. Baines, Selous, Harvey Brown, and others encountered 

 the " tsetse fly." and recorded the heavy mortality of stock which 

 followed its bite. Many of the areas of infection defined by 

 them exist to this day. although the devastating passage of 

 rinderpest during 1896 apparently caused a check not only to the 

 disease but to the " flies " themselves, which, d.iminished con- 

 siderably in niimbers and distribution. I am obliged to my 

 colleague, Mr. Rupert Jack, (rovernment Entomologist, for a 

 map which shows very concisely the present and past distribu- 

 tion of Glossina iiiorsitaiis in Southern Rhodesia. This indicates 

 that recently the " tsetse fly " has to- some extent regained ground, 

 and Neave has made the same ohservation, confirmed by the 

 natives in the northern territories. 



The economic importance of these animal trypanosomiases 

 is greater than appears at first sight. Large areas of valuable 

 territory are rendered inaccessible by animal transport and can- 

 not be opened up, or, when served by a railway, agricultural, 

 ])astoral and mining development is severely handicapped if not 

 impossible. And when it is remembered th.at some three hundred 

 thousand human heings are said to have succumbed to sleeping- 

 sickness in Uganda during the past few years, the gravity of 



