Establishment of Indirect ELISA Detection Method for Porcine Epidemic Diarrhea Virus

Porcine epidemic diarrhea (PED) is an acute, highly contagious enteric disease of pigs. Porcine epidemic diarrhea virus (PEDV) is the causative agent of PED. PED has caused significant economic losses to the pig industry. In this study,the purified PEDV as the coating antigen, by optimizing the ELISA reaction conditions,the indirect ELISA antibody detection method was established. The optimized reaction conditions were as follows: Antigen working concentration was 20 μg/mL; Serum sample dilution was 1:500;It was coated at 4℃ overnight; The plates were blocked by 5% calf serum incubated at 37℃ for 1 h; The secondary antibody was diluted at 1:10 000,incubated at 37℃ for 1 h. It was judged as positive when the cutoff value D_{450 nm}≥0.289,as negative when D_{450 nm}≤0.236,and as suspicious between 0.289 and 0.236.It could not react with the positive sear of other six viruses such as porcine respiratory and reproductive syndrome virus,porcine circovirus 2, classical swine fever virus, porcine parvovirus,pseudo rabies virus and foot-and-mouth disease virus. The variation coefficient of repeated test was less than 10%.74 pig serum samples from Jiangsu, Jiangxi, Fujian and Guangdong were detected,and the positive rate was 84%.It indicated that this method could be used for PEDV epidemiological surveys and diagnosis in the future.