IMMUNIZATION OF CATTLE IN ZIMBABWE USING THEILERIA-PARVA (BOLENI) WITHOUT CONCURRENT TETRACYCLINE THERAPY

Five hundred and ten cattle were immunised using the Theileria parva ( Boleni) stock without concurrent chemotherapy with tetracycline on 2 f arms in Zimbabwe, both of which had a history of theileriosis. The sta bilate had been titrated in Friesian calves to determine a 50% protect ive dose (PD50) and 2 or 3 (PD50s) were used to immunise the cattle. N one of the cattle showed a clinical reaction following the immunisatio n procedure. However, the cattle were shown to have responded immunolo gically on testing for antibodies to a T. parva antigen in an indirect fluorescent antibody test. The immunised cattle were then exposed to a natural field challenge causing severe theileriosis in control cattl e. Immunisation against theileriosis without the need for concurrent c hemotherapy is much less expensive than the infection and treatment me thod (US$2.72) compared to US$10.23 in the first year) and would be mu ch more attractive to commercial and traditional farmers.