Evaluation of attenuated variety of Neospora caninum for diagnosis of infection in cattle by agglutination test

The protozoan parasite Neospora caninum is a major cause of abortion in cattle worldwide. It has been found in various animal species such as dogs, cattle, horses, sheep and goats. This is conclusive proof that long-term passage of tachyzoites in tissue culture can attenuate virulence of Neospora caninum in vivo. But whether the attenuation procedure could reduces the diagnostic value of attenuated variety is the issue of the impact that this study tries to evaluate it. In other word the aim of this study was to evaluate the attenuated variety of Neospora caninum for diagnosis of neosporosis in cattle by agglutination method. The study was conducted with 184 sera collected from cattle with a history of abortion during the past year from the farms of Fars province. The sera were tested for the detection of antibodies against Neospora caninum with commercial ELISA kit and agglutination method. The results of this study showed that the positivity rate for the sera was 54 (29.34%) for agglutination method compared to 59(32.07 %) obtained by ELISA kit. The difference of agglutination method with ELISA kits according to the McNemar test was not significant and this result was also very good agreement with the Kappa test. This study proved that the attenuated variety of Neospora caninum still preserves its own diagnostic value.