Epidemiology of tick-borne diseases of cattle in Zimbabwe. III. Theileria parva group.

A survey of the occurrence of antibodies to Theileria parva using the IFA test in calves up to one year old at 244 localities in Zimbabwe revealed that the parasite occurred throughout the country although the prevalence of positive serological reactors was generally low. Outbreaks of theileriosis in high rainfall areas in the north, east and west of the country were attributed to Theileria parva bovis transmitted from cattle to cattle by Rhipicephalus appendiculatus. Outbreaks in high and low rainfall areas in the south and west of the country were attributed to Theileria parva lawrencei transmitted from buffalo to cattle by Rhipicephalus zambeziensis or R. appendiculatus. R. appendiculatus was not uniformly distributed in Zimbabwe. It occurred very commonly in foci in the commercial farming areas but was rare in most overgrazed communal farming areas. Outbreaks of disease attributed to T. parva bovis were recorded in some but not all the R. appendiculatus foci. The disease was present in areas infested with R. zambeziensis but it did not cause cattle deaths in these areas.