Neospora caninum in aborted twin calves.

Neospora caninum was detected in the brains of twin aborted calves by means of a specific immunohistochemical test on formalin-fixed, wax-embedded tissues. Microscopic lesions associated with this infection included multifocal necrosis and gliosis in the brain accompanied by a mononuclear, perivascular inflammatory reaction and meningitis; and severe, diffuse epicarditis and subepicardial myocarditis characterised by infiltration of macrophages, lymphocytes and plasma cells. This report documents the first diagnosis of this parasite as a cause of bovine abortion in South Africa.