Establishment and Application of Multiplex PCR Assay for Detection of Porcine Parvovirus and Porcine Circovirus Type 2

Porcine parvovirus(PPV) and porcine circovirus type 2(PCV2) are two main viral pathogens of porcine reproduction barrier diseases.To identify and differentiate rapidly the cause(s) of clinical diseases,a multiple PCR/ RT-PCR assay was developed.Based on the similarity of the viral sequences deposited in the GenBank database,the VP2 gene of PPV and the ORF2 gene of PCV2 were selected as the diagnostic targets.By using two pairs of virus-specific primers,two PCR/ RT-PCR assay were established to amplify the conservative regions of the two viruses,respectively.Consequently,a multiplex PCR/ RT-PCR method to detect the two viruses in one tube was developed.The multiple PCR/RT-PCR system would amplify a 313 bp fragment for PPV and a 447 bp for PCV2 simultaneously or separately in the samples,depending on its infection status.By comparison,the test proved that the multiplex PCR method being 100% coincidence with the single PCRs,and it could be used for this two virus detection and differential diagnosis.211 samples of pigs collected from 10 nosopoietic pig farms and outpatient cases were detected with the multiplex PCR assay studied by group,the result showed that the positive rate of 56 positive PCV2 was 27% and the positive rate of 42 positive PPV was 20%,and the positive rate of 17 two diseases mixed infection was 8%.The study provided a basis for the infection situation of these two diseases in Shanxi.