The differential diagnosis of the bovine theilerias of Southern Africa.

It is currently thought that the following species or sub-species of Theileria occur in cattle in southern Africa: Theileria parva parva (East Coast fever), Theileria parva lawrencei (Corridor disease), Theileria parva bovie (Rhodesian theileriosis), Theileria mutans proper (transmitted by Amblyomma species), so-called Theileria mutans (a non-pathogenic species transmitted by Rhipicephalus appendiculatus, possibly identical with Theileria taurotragi) and Theileria velifera. The parasites can be differentiated on serological, morphological and epidemiological grounds. The four true species are serologically distinct. T. mutans proper and T. velifera show morphological differences from the other two species in some stages of their development. The T. parva group are the only parasites that are commonly pathogenic. Differentiation of the three members of this group is based on differences in the numbers of schizonts and piroplasms present and on differences in the epidemiology of the diseases they cause.