Some observations on trypanosoma pecorum (Bruce) and T. uniforme (Bruce)

Abstract

The fact that antelope play a considerable part in nature as a reservoir for T. gambiense has now been thoroughly established. Both laboratory and field results agree in confirming the suspicion which for some time past has attached to these animals. In the case of T. gambiense , however, there is nothing very remarkable in the observation that the presence of the trypanosome in their blood apparently exerts no harmful effect on the antelope. T. gambiense cannot be considered as a fatal trypanosome for ruminants generally. In the case of pecorum, however, matters are different. This trypanosome, according to Bruce and his collaborators, causes a rapidly fatal disease in cattle and domestic animals generally. Though apparently widely distributed throughout Uganda, nothing definite is at present known concerning its true carrier in nature. The presence of the disease in districts where tsetse are unknown shows that some other agent is capable of conveying this trypanosome. The behaviour of laboratorybred Glossina palpalis as carriers is so uncertain that this fly would appear at most to be a facultative host, though doubtless under favourable circumstances it may play an important part in nature. Again, nothing is known concerning the existence of a natural reservoir for this trypanosome in Uganda, though Kleine has recently obtained species closely allied to, if not identical with, T. nanum and T. congolence from antelope in the neighbourhood of Tanganyika. The following experiments were undertaken with a view to discovering whether T. pecorum is pathogenic to antelope, and at the same time to test the power of these animals to act as a reservoir for the trypanosome:— A young bushbuck, born at the laboratory in January, 1911, was inoculated with blood of a monkey suffering from T. pecorum . After an incubation period of 15 days trypanosomes appeared in the blood of the bushbuck on May 31, 1911, being present for some days and then disappearing. Clean laboratory-bred G. palpalis were then fed upon the bushbuck and afterwards on clean monkeys. Those experiments are given in Table I. As will be seen, in only one instance was a positive transmission obtained, and this was unfortunately not entirely satisfactory, as will be explained below.