Abstract: A duplex PCR assay for detection of pseudorabies virus (PRV) gE-deleted vaccine and PRV was established using the primers designed based on the characteristics of PRV possessing surface antigen gD and gE virulence genes, and PRV gE-deleted vaccine only owing gD gene but no gE gene. The specificity, sensitivity and repetition tests were conducted, moreover, samples which were taken from clinic suspicious PRV infected pigs had been testified by the established duplex PCR assay. The results showed that a duplex PCR assay for detection of PRV gE-deleted vaccine and PRV was successfully established. The sensitivity and specificity of the duplex PCR assay revealed that the threshold of the duplex PCR was 100 copies/μL of gD or gE gene, and gD/gE gene could be amplified specifically from wild virus or gD gene from PRV gE-deleted vaccine but no products were amplified from the nucleic acid of PK-15 cell or the other 8 kinds of pathogenic viral or bacterial microorganism. The four repetition tests indicated that the duplex PCR was repeatable. Total of 267 gD and gE positive samples and 28 gD positive samples were detected from 835 clinic suspicious PRV infected pigs. Selecting 26 PRV gD and gE positive samples detected by the duplex PCR assay for pathogen cell culture, the coincidence rate between the two methods was 96.1%. The study suggested that the established duplex PCR method was highly specific and sensitive, and was suitable for clinic rapid differential diagnosis of PRV gE-deleted vaccine and PRV.

Key words: pseudorabies virus (PRV); gE-deleted vaccine; gD/gE gene; duplex PCR; differential diagnosis