34 
TKYrANOSOMIASlS IN THE ANGLO-EHYrTIAN SUDAN 
What is the 
common mule 
trypanosome? 
Value of 
cultural 
methods 
I'he short 
trypanosome, 
is it T. r 
As regards animal reactions, Laveran notes that with T. ppcaudi there is in the case of 
mice no disease running a slow coui'se, and with enormous splenic enlargement, as is found 
with T. (iiiiKirplwn. 
He has shown that a sheep recovered from dirnorplion infection could be inoculated 
with T. peraudl, and, it such experiments are reliable as tests, has in a similar way proved 
the specificity of T. pecaudi, so far as the trypanosome of Mbori (var. T. evan.^i) and 
T. xondanensa go. When an animal immune to Mbori is inoculated with T. pecaudi, ludli 
faniis of the latter trypanosome appear in its blood. 
Bouffard mentions that the marked susceptibility of guinea pigs to T. pecaudi helps to 
distinguish it from 7'. dimorphon, as the latter is not found in large numbers in the blood of 
inoculated guinea pigs. 
Bouet, who thinks it is easy to distinguish typical T. dimorphon from tyjjical T. pecaudi, 
except when the former shows forms with free flagella, regards Baleri as a more severe 
form of trypanosomiasis than that produced by T. dimorphon. 
Turning now to the Sudan trypanosome, one finds that the long and very thin form 
found in mules certainly tends to disappear when passed through a long series of gerbils, but, 
at the same time, there is no doubt that two forms—a long form with a well-marked free 
flagellum and a short thick form with no free flagellum—do persist. I remember that two 
guinea pigs inoculated from gerbils became inoculated and, I think, showed a good infection. 
One of them died of the disease. I do not remember ever having seen the trypanosome 
agglutinate under the cover glass, though 1 have examined hundreds of specimens. After a 
careful study of the French work, and speaking, perforce, to some extent from memory, 
r think that Laveran is correct in supposing that the mule trypanosome of the Sudan is more 
like T. pecaudi than T. dimorphon. One, however, asks the question, are these valid types '? 
Is the disease not merely nagana and the parasite T. hrucei ? We know the latter assumes 
various forms in the blood, and when I submitted a slide of gerbil's blood, showing the mule 
trypanosome, to Colonel Bruce, he declared it to he exactly like T. hrucei. 
At the present time we cannot go further, but it is hoped, especially by cultural and 
possibly by therapeutic work, to clear up much that is confusing and doubtful. It is 
important to ascertain the precise species of trypanosomes present in the Sudan, for much 
may depend on this when preventive measures and treatment call for consideration. The 
French work is certainly very suggestive, but it is well to keep an open mind. In any case 
I believe the mule trypanosomiasis to be carried by the tsetse fly—chiefly by G. moj-sitans, 
and this for reasons fully explained in the last Report. It is perhaps worthy of note that 
Cazalbou is inclined to regard Baleri as a tsetse disease, the ass being the reservoir of 
the virus. 
The suggestion made by Dutton, Todd and Kinghorn' referred to T. nannin. They 
asked if this trypanosome might not be merely the “ tadpole ” form of their T. dimorphon. 
Dr. Wenyon’s work on this parasite shows that this is unlikely. T. na.num is not 
always of the “ tadpole ” type, and now that dogs and a gerbil have been successfully 
inoculated, the available evidence tends to prove that it is a distinct species and that 
Laveran was correct in giving it a specific name. The disease produced by it differs from 
that caused by 7’. dimorphon, but the Liverpool observers suggest that the “ tadpole” forms 
may be present in chronically infected animals, and that they give place to the “ stumpy ” 
and “ long ’’ forms as the disease becomes more acute, in either the original host or in sub- 
inoculated animals. Personally I have seen no evidence of this as regards T. nanum, 
' Dutton. ,T. E., Ttitld, J. L.. nnd Kine^horn, A. (.June ‘2nd, 19(^7), “Cattle Tryp.auosomiasis in the Congo Free 
Stiitc.” AirniiJn Livrrj/oo/ SAioitl of y'ro//lc(fI Mrih'rinf', Vol. I., No. 2. 
