Attempted transmission ofBabesia major byBoophilus microplus

Summary

Two experiments were carried out to determine ifBabesia major could be transmitted byBoophilus microplus. In experiment 1, aBabesia-free batch of laboratory rearedBo. microplus larvae were applied to an intact calf infected by inoculation with aB. major stabilate. The calf showed aB. major parasitaemia while the larvae, nymphs and adult ticks were engorging. The engorged females were cultured and batches were incubated at one of the three following temperatures: 24, 28 or 32°C. Approximately 10,000 larvae derived from each of the females were used to infest each of three splenectomized calves. In experiment 2,Babesia-freeBo. microplus larvae were applied to a splenectomized calf; the calf was injected withB. major stabilate and showed aB. major parasitaemia during the adult stage of tick development. The engorged females were incubated at room temperature and the resulting larvae (approximately 10,000) were used to infest a splenectomized calf. Examination of blood films for the presence ofB. major from the four calves infested by the second generation larvae in the two experiments were negative.