Epidemiology and transmission of Theileria sp of cattle in Australia.

Theileria sp occurs in cattle in Australia where Boophilus microplus is not present. Two species of ixodid ticks namely Haemaphysalis longicornis and H. bancrofti have been implicated as natural vectors. Experimental transmission was obtained with these two species but attempts to transmit the infection with B. microplus, Ixodes holocyclus and Amblyomma triguttatum were not successful. Although calves born in the enzootic area may become infected before one-month-old most show evidence of infection by 5 months of age. Calves born in the winter also become infected earlier than those born at other times of the year.