Three experiments were undertaken to determine the efficacy of different doses of
buparvaquone in the
infection and treatment immunization of cattle against Theileria parva derived from African buffalo (Syncerus caffer). Two of these experiments also compared
buparvaquone with standard doses of long- and short-acting formulations of
oxytetracycline. In addition, different dilutions of stabilates were used in the experiments. In the first experiment,
a 10(-1.0) dilution of stabilate was used to infect groups of cattle treated with
buparvaquone at doses of between 5 and 0.625 mg kg-1
body weight (bwt) on Day 0 after
infection. All control cattle developed severe
theileriosis and none of the treatment regimes (including those utilizing long-acting
oxytetracycline) prevented the development of
theileriosis. Treatment with
buparvaquone at 2.5 mg kg-1 bwt or
oxytetracycline gave the most satisfactory results. In the second experiment when the sporozoite dose was reduced to 10(-2.0) dilution,
buparvaquone treatment at 5 and 2.5 mg kg-1 bwt and short- and long-acting formulations of
oxytetracycline reduced reactions greatly. While all the
oxytetracycline treated animals produced a serological response and were immune to a 50-fold higher challenge with the immunizing stabilate, several animals in the
buparvaquone groups did not show a serological response and were not immune to challenge. In the third experiment, groups of cattle were infected with 10(-1.2), 10(-1.4) and 10(-1.6) dilutions of stabilate and were treated with 2.5 mg kg-1 bwt of
buparvaquone. No animals developed severe
theileriosis and all seroconverted. On homologous challenge, however, two out of 14 cattle showed severe reactions. It was concluded that further work on immunization using
buparvaquone treatment at 2.5 mg kg-1 bwt and 10(-1.6) dilution of the stabilate would have to be carried out before such a system could be used in the field.