Bovine abortion associated with Neospora caninum in northern Spain

During 1996, aborted bovine fetuses from dairy herds in northern Spain were examined by histopathological, immunohistochemical and serological methods for evidence of infection by Neospora caninum. Microscopical brain changes consistent with those of neosporosis were detected in 36 of 81 fetuses and specific antibodies (IFAT titres greater than or equal to 1/16) in 32 of 6 3. Eight fetuses with neurological lesions were seronegative, and eight wit hout lesions were seropositive. In 25 of 34 fetal brains with lesions consi stent with published descriptions of neosporosis immunohistochemical analys is revealed the presence of N caninum antigen. Depending on the diagnostic criteria, the prevalence of neosporosis related to bovine abortion was betw een 32 and 57 per cent of the fetuses submitted and between 33 and 58 per c ent of the herds involved. Data on the geographical, seasonal and fetal age distribution of the infection are given for the fetuses examined and the v alue of the different diagnostic methods is discussed.