Susceptibility of different breeds of goats in Kenya to experimental infection with Trypanosoma congolense.

To assess whether there was any evidence of genetic resistance to African trypanosomiasis, five breeds of goat (East African, Galla, and crossbreds between East African and Galla, Nubian or Toggenburg) were experimentally infected with Trypanosoma congolense either by needle inoculation or by tsetse-transmission. The goats had not been previously exposed to trypanosomiasis. With both methods of infection all breeds were found to be highly susceptible and suffered severe disease. Following tsetse-transmitted infection no significant differences were observed between breeds in the development, duration and size of the chancre reaction or in the degree and duration of parasitaemia. While Nubian goats developed anaemia more rapidly than the other breeds, all animals experienced a pronounced reduction in packed red cell volume. Similarly following needle inoculation no differences were found between breeds in the severity of anaemia or in the kinetics of parasitaemia. Immune responses against both metacyclic and bloodstream trypanosomes of the infecting serodeme were similar in all breeds as were the erythropoietic responses to the infection. No alterations in leucocyte parameters occurred.