Development and application of an indirect ELISA for the Neospora caninum based on a fusion protein rSRS2- SAG1-GRA7

Introduction: Neospora caninum is an important apicomplexan parasite causing neosporosis in cattle. The disease is recognized as one of the most important cause of reproductive problems and abortion in cattle worldwide. In this context, we developed an indirect ELISA with fusion protein rSRS2-SAG1-GRA7 for the diagnosis of neosporosis in aborted dairy cattle. Results: : The reaction conditions of the developed indirect ELISA were optimized. This indirect ELISA was compared to indirect immunoinfluscent assay (IFA), a total of 56 sera samples from cattle were used to evaluate the ELISA, the antibodies against N. caninum were tested by this ELISA to evaluate the prevalence of N. caninum in Ningxia. The sensitivity and specificity results of the rSRS2-SAG1-GRA7 indirect ELISA were 83.33% and 100%, the overall coincidence rate was 94.64%. N. caninum was prevalent in all the 4 cities investigated in Ningxia. The positive rate was from 16.67 to 100 %, and the mean rate was 41.64%. Conclusions: : This established rSRS2-SAG1-GRA7 indirect ELISA is capable of detecting serum antibodies against N. caninum , and due to its high sensitivity and specificity, it could be applied for serological evaluation and indirect diagnosis of N. caninum infection. And we assessed N. caninum seroprevalence in aborted dairy cattle from Ningxia province of China with this rSRS2-SAG1-GRA7 indirect ELISA.