24 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
III. EQUINE TRYPANOSOMIASIS 
The first trypanosome which we found while in the Gambia was in the blood 
of a horse, and this is the only animal in which we have seen a certainly pathogenic 
trypanosome. 
Out of thirty-six horses examined, ten were found to be infected. The 
parasites derived from three of these animals have been, and are still being, studied. 
They, as far as we can see, are all of the same variety, and do not correspond in 
every respect with any of the described trypanosomata, although in a general way 
they resemble those species already described as pathogenic to horses. 
Pending a further study of their properties, we shall describe them as one 
species, under the style of ' The Gambian Horse Trypanosome.' 
Distribution and Prevalence 
One of our first cares in the Gambia was to obtain data showing the amount 
of live stock of all sorts in the country, and to learn in exactly what localities the 
various animals throve or not. 
To aid us to this end, Sir George Denton, K.C.M.G., the governor of the 
Gambia, very kindly sent out a circular letter, containing questions on the subject, 
to all the District Commissioners. 
From the information thus acquired, together with that obtained from traders 
and natives and supplemented by our own observations, we have drawn the following 
conclusions : — 
1. Equine trypanosomiasis in the Gambia is a very chronic disease. 
2. It occurs throughout the colony, and is possibly more prevalent 
near the river, especially during the rainy season. 
3. Cattle and other domestic animals are not known to suffer from 
the disease. 
The total number of horses in the Gambia is not large, probably not 
more than 1,000 altogether. In some districts there are very few, in others there 
are absolutely no horses nor, indeed, cattle. The natives explain this by their 
poverty, saying that they cannot afford to buy horses and cows. Others, again, 
are fishermen or pagan agriculturists and carriers, e.g., the Jolahs ; and do not keep 
live stock other than goats, which thrive everywhere. There are more horses on the 
northern bank of the Gambia, particularly of the upper river than on the southern. 
