Immunisation 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 farms in Zimbabwe, both of which had a history of theileriosis. The stabilate had been titrated in Friesian calves to determine a 50% protective dose (PD50) and 2 or 3 (PD50s) were used to immunise the cattle. None of the cattle showed a clinical reaction following the immunisation procedure. However, the cattle were shown to have responded immunologically 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 cattle. Immunisation against theileriosis without the need for concurrent chemotherapy is much less expensive than the infection and treatment method (US $2.72) compared to US $10.23 in the first year) and would be much more attractive to commercial and traditional farmers.