Interaction between Trypanosoma evansi and Haemonchus contortus infection in goats

An experimental study on interaction between Trypanosoma evansi and Haemonchus contortus infections was conducted in 42 male Barbari goats of 6-9 months age. Parasitological observations like prepatent period, faecal egg count, worm burden and mortality were made in animals infected with H. contortus followed 1 week later with T. evansi and vice versa. These parameters were also examined in animals with single infection with each of these parasites. It was revealed that T. evansi infection in goats lowered the normal resistance to H. contortus. The prepatent period was markedly reduced to 16-18 days in cases where T. evansi preceded H. contortus as compared to 21-25 and 21-23 days in single H. contortus and in a H. contortus preceding T. evansi infection, respectively. The rate of L(3) establishment was significantly enhanced in infection where T. evansi preceded H. contortus. A higher rate of mortality and more pronounced pathological effects were observed in combined infections than in single ones.