Development And Application Of An Indirect ELISA For The Neospora Caninum Based On A Fusion Protein RSRS2-SAG1-GRA7

Neospora caninum is an apicomplexan parasite with a variety of intermediate hosts,and its terminal host is the canids.N.caninum can cause neurological and reproductive system disorders in dogs and a variety of animals,cause the most serious harm to cattle,aborting of cattle caused by neosporosis results in enormous economic losses in the cattle industry worldwide.Therefore,the establishment of indirect ELISA testing methods for cattle neosporosis is important for the diagnosis and control of neosporosis.In this study,based on the principle of homologous recombination,the Nc SRS2,Nc SAG1 and Nc GRA7 genes were linked to the p ET-28 a vector skeleton,and the28a-S2-G1-A7 expression plasmid was constructed and induced expression of the N.caninum r SRS2-SAG1-GRA7 fusion protein.After the purified fusion protein was qualified for reactivity and specificity,an indirect ELISA for diagnostic cattle neosporosis was established using the purified fusion protein as a diagnostic antigen.The reaction conditions of this assay were optimized and its critical value was determined.The method was high sensitivity,specific and reproducible,and compared with the authoritative method IFA,this method has excellent sensitivity and extremely high specificity.This assay was used to investigate aborting dairy cattle in several cattle farms in Ningxia.The results showed that the prevalence rate of all cattle farms ranged from 16.67% to100%,and the total prevalence rate of neosporosis in the area was 41.64%.The research of this paper has good application value,and the research results will provide a new effective method for the serological diagnosis and epidemiological monitoring of neosporosis of cattle.