Studies on transmission of two East African stocks of Trypanosoma vivax to cattle, goats, rabbits, rats and mice.

Transmission studies were conducted using two Trypanosoma vivax stocks isolated from bovines in Uganda. Parasitaemia was low and transient in rabbits and rats; it persisted for relatively longer in NMRI mice. The parasitaemia developed to a peak in a few A/J and Balb/c mice; in NMRI, C57B and C3H/He it was low and fleeting. Lethally irradiated A/J, C57B and C3H/He mice with caesium 137 at 900 Gy showed a high peak of parasitaemia; NMRI and Balb/c mice succumbed very rapidly to a similar radiation dose. Serial maintenance of one stock of T. vivax was achieved in normal NMRI and lethally irradiated A/J mice. Both stocks failed to develop in the proboscis of Glossina morsitans morsitans or of G. m. centralis, and hence cyclical transmission to goats also failed. However, non-cyclical transmission by tsetse from goat to goat, and from cattle to goats, was successful. The infection caused acute and fatal disease in goats which were anaemic at death. The Boran cattle used eventually suppressed the infection and recovered.