Rinderpest vaccination and the incidence and development of trypanosomosisin cattle

An investigation was made into whether recent vaccination of cattle with ti ssue culture rinderpest virus would cause immunosuppression and lead to mor e frequent or more severe infection with trypanosomes in animals grazing in tsetse-infested areas. Herds of cattle on Galana Ranch in Kenya were divid ed, with approximately half of each herd being vaccinated with tissue cultu re rinderpest virus strain Kabete 'O', while the rest remained unvaccinated . The herds were then exposed to the risk of natural infection with trypano somes on the ranch. Three experiments were performed during different seaso ns. Infections with Trypanosoma congolense and Trypanosoma vivax were frequ ently detected but there was no evidence that vaccinated animals were more likely to acquire trypanosome infections or to show a more severe disease t han unvaccinated cattle. It is concluded that tissue culture rinderpest vac cine does not cause immunosuppression and can safely be used in cattle like ly to be exposed to tsetse flies and trypanosomosis.