Elimination of Theileria buffeli infections from cattle by concurrent treatment with primaquine phosphate and halofuginone lactate.

Fifty splenectomised calves naturally infected with Theileria buffeli were treated with primaquine phosphate (ICI, UK) and halofuginone lactate (Hoechst, Australia) either separately or in combination. Infections in treated calves were monitored for up to 26 weeks by examining Giemsa stained peripheral blood films for piroplasms and by an immunofluorescent antibody test. When used alone neither of the drugs eliminated infection. The most successful results were obtained when two treatments of halofuginone lactate, at a rate of 1 mg kg-1 body weight and six treatments of primaquine phosphate, at a rate of 2 mg kg-1 body weight, were administered concurrently. No theilerial relapses were observed in 14 of 16 calves so treated, and no antibody to T. buffeli was detected in these calves beyond the twelfth week after treatment. The results have application in the preparation of Theileria-free calves for use in the production of living vaccines against babesiosis and anaplasmosis.