Development and Application of A RT-PCR Method for Detection and Differentiation of Classical and Variant Porcine Reproductive and Respiratory Syndrome Virus

To establish a rapid differential diagnosis method of porcine reproductive and respiratory syndrome virus(PRRSV) classic and variant strains,a pair of primers corresponding to the highly conserved regions of Nsp2 gene of PRRSV genome were synthesized according to the sequences of PRRSV on GenBank,a RT-PCR method for detection and differentiation of classical and variant PRRSV was established.A fragment of 549 and 459 bp was amplified from genomic RNA of classical or high-pathogenic PRRSV respectively,no specific products were achieved after differentiating detection of porcine originated viral pathogens including HCV,JEV,PEDV,TGEV,PRV,PCV2 and PPV.The RT-PCR could detect 1 pg RNA of classical and 0.1 pg RNA of variant PRRSV respectively.The established RT-PCR method had good specificity,sensitivity,repeatability,could accurately and quickly identify the classical and variant PRRSV,it provided a kind of efficient,rapid,specific and sensitive detection method for clinical diagnosis,disease detection and molecular epidemiology of material such as porcine reproductive and respiratory syndrome virus.