Neosporosis in Mexican dairy herds: Lesions and immunohistochemical detection of Neospora caninum in fetuses

Of 211 aborted bovine fetuses collected from Mexican dairy herds between Ja nuary 1996 and March 1999, 73 showed microscopical lesions consistent with neosporosis. Of these 73 fetuses, 38 (79%) showed lymphocytic myocarditis, 39 (53%) showed microgliosis and multifocal necrosis in the brain, 39 (53%) showed lymphocytic hepatitis, and 19 (26) sowed lymphocytic myositis. Immu nohistochemical examination of brain, myocardium and liver from 53 of the s ame 73 fetuses demonstrated, Neospora caninum antigens in 41 (77%), of whic h 19 (46%) gave positive results in one of the three sites. 15 (37%) in two , and seven (17%) in three. The results indicated the presence of neosporos is in a number of the main dairy farming regions of Mexico. (C) 2001 Harcou rt Publishers Ltd.