Establishment Of Indirect Competitive ELISA For Rapid Diagnosis Of Transmissible Gastroenteritis Virus

The virions were lysed by nonionic detergent and the nucleoprotein was exposed. The selection of blocking solution and other paremeters were optimized, the analyzation shows that blocking for 2h at 37℃with 0.5% PVP induces the best result. Indirect competitive ELISA method was established with the recombinant nucleoprotein(rNP)of transmissible gastroenteritis virus(TGEV)and the monoclonal antibody against TGEV N protein to detect intestinal contents of 20 piglets infected with TGEV. The inhibition ratio of the samples which were more than 14.5% was regarded as positive value under the condition that N OD492nm >0.9 by statistical analysis. The specific assay was carried out by indirect competitive ELISA method and the results showed that the detection of porcine rotavirus (PRV) and porcine epidemic diarrhea virus (PEDV) were negative.Colostrum-deprived piglets were orally infected with TGEV TH-98 virulent strain, and the faecal samples were collected since 24 hours post-infection. Indirect competitive ELISA and RT-PCR were carried out for the detection of TGEV. Enteric proliferated TGEV were detected by indirect competitive ELISA in faecal samples obtained since 62 hours post-infection and also detected by RT-PCR in faecel samples taken since 57 hours post-infection. TGEV was detected by RT-PCR 5h earlier than by indirect competitive ELISA. TGEV can be detected by RT-PCR and indirect competitive ELISA in 10-fold diluted faecal samples taken ever since 63h post-infection. However, TGEV in 20-fold and 40-fold diluted faecel samples could only be detectied by RT-PCR. Results shows that RT-PCR is more sensitive than indirect competitive ELISA.