The use of immunochistochemistry for the diagnosis of neosporosis in cattle and dogs

Abstract Extract A goat anti-Neosporum caninum serum and an avidinbiotin-peroxidase conjugate were used in a retrospective study of paraffin-embedded tissues from aborted calves and CNS tissues from dogs with neurological disease. Labelled cyst-like structures and individual or clusters of zoites were found in the brain of some aborted calves, usually associated with necrotic foci. No protozoa1 organisms could be clearly identified in the placentae of the same animals. Labelled cysts and zoites were found in the brain and spinal cord of three of 15 dogs with CNS lesions. The three dogs had a history of nervous signs and had previously been misdi- agnosed as having toxoplasmosis or granulomatous meningoencephalomyelitis.