Evaluation by different diagnostic techniques of bovine abortion associated with Neospora caninum in Spain

Eighty foetuses from some of the main cattle-producing regions in Spain were analysed to investigate the participation of Neospora caninum in cases of bovine abortion. Diagnosis of the infection was determined by histopathological analysis complemented with immunohistochemistry, serology (IFAT and ELISA) and PCR tests. A total of 38.8% of the bovine foetuses analysed were considered to be infected by at least one of the diagnostic techniques used. Microscopic lesions consistent with Neospora infection in brain were identified in 31.3% of the samples, whereas only 10.7 and 15.3% were positive using serological and PCR analysis, respectively. Perfect agreement was shown between IFAT and ELISA, although there was little agreement among results of the other diagnostic techniques. Gestational age of aborted foetuses checked ranged from <3 to 9 months, with a mean of 5.9 months, and no difference in age was found between infected and non-infected foetuses (P>0.05). This study confirms the importance of N. caninum as a cause of abortion in Spain and underlines the need to use different diagnostic techniques to increase the chance to detect the infection in aborted foetuses.