The significance of Eperythrozoon ovis in ill-thrift in sheep in the eastern Cape coastal areas of South Africa.

Ill-thrift in sheep in the coastal region of the Eastern Cape is described. It is shown to be a complex problem attributable to many causes, most of which can be eliminated by supplementary feeding, drenching, vaccination, dipping and management. However, studies on the aetiology of ill-thrift in young sheep indicate that arthropod-borne anaemia-producing pathogens are an important contributing factor, which cannot readily be diagnosed and controlled. Experiments were conducted on various farms to determine whether Eperythrozoon ovis occurred in sheep in the coastal areas of the Eastern Cape and to what extent infection affected these animals. Other blood parasites found in sheep in the Eastern Cape included Borrelia theileri, Anaplasma ovis, Ehrlichia ovina, Cytoecetes phagocytophila and Theileria ovis. E. ovis, either alone or in combination with one or more of these parasites, caused a severe prolonged anaemia accompanied by the development of ill-thrift.