21 
THYPANOSOMES FOUND IN CANADIAN 
MAMMALS. 
By E. a. WATSON, V.S., and S. HADWEN, D.V.Sci. 
Department of Agriculture, Canada. 
(Plates I and II.) 
Since 1906 trypanosomes have been found in ten species of mammals 
by oflScers of the Health of Animals Branch. 
Only one of these parasites has been proved to be pathogenic, i.e. that 
of Dourine. 
As will be seen by referring to the plates, several of the apparently 
non-pathogenic forms bear some resemblance to those trypanosomes 
which are well known to produce fatal diseases. 
Other Canadian mammals doubtless harbour trypanosomes and 
further species will be recorded. 
Intense cold seems to have little effect on the range of these parasites, 
and it is interesting to note that virulent outbreaks of Dourine have 
occurred in places where the thermometer sometimes drops to 50° and 
60° F. below zero. However, the identity or the non-identity of this 
trypanosome with that of African Dourine remains open to question, 
and, on similar grounds, the identity of the African with the so-called 
Indian and European varieties may well be doubted. 
The Dourine of Canada appears to be identical with Beschalseuche 
of East Prussia, the Dourine of Hungary and that of Eastern Europe. 
In any of these, the trypanosome is rarely, if ever, found in the general 
circulation of infected animals, but only in the serous or sanguineous 
fluids of local swellings and infiltrations which are characteristic of the 
malady; further, they closely correspond in that laboratory animals are 
V 
