Bovine theileriasis in South Africa with special reference to Theileria mutans

Abstract

1. It would appear that in East Coast fever areas in South Africa, the appearance of Koch's bodies in organ smears in a large percentage of single deaths must be attributed to T. mutans. 2. Under certain conditions T. mutans in non-East Coast fever areas may assume the pathological picture of T. parva from which it cannot be differentiated. It is, however, believed that under natural conditions in South Africa this seldom occurs. T. parva on the other hand causes mortality direct without the operation of other agencies without which T. mutans remains a harmless parasite. 3. Acute theileriasis in South Africa (T. parva and T. mutans) under certain conditions is associated with fairly characteristic changes in the lymphoid system particularly as revealed in the spleen and lymph glands. The pathogenesis of this is at the present moment not yet understood. 4. Although the Koch's bodies of T. mutans, after splenectomy, is of the nature of a "relapse", yet at the present moment it is not possible to state whether the greater majority of cases is of such a nature, or a re-infection, probably with a different strain. If it is of the nature of a relapse, then the pathogenesis of the various agencies that can bring this about is not yet understood. 5. The present East Coast fever policy, with the full co-operation of the farming community should be persisted in to eradicate the disease in South Africa, and every endeavour should be made to carry out the slaughter out policy where East Coast fever has been diagnosed.