2007～2010年江苏地区猪繁殖与呼吸综合征病毒RT-PCR检测及部分Nsp2基因序列分析

RT-PCR DETECTION AND PARTIAL NSP2 GENE ANALYSIS OF PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME VIRUS IN JIANGSU PROVINCE FROM 2007 TO 2010

本研究参考GenBank已发表的猪繁殖与呼吸综合征病毒（Porcine reproductive and respiratory syndrome virus，PRRSV）Nsp2基因序列，在高致病性病毒Nsp2基因缺失区的两端保守区设计并合成了一对引物，建立并优化了能够区分经典PRRSV和高致病性PRRSV的RT-PCR诊断方法，并利用该方法对2007～2010年间江苏地区的45份可疑临床病料进行了检测。结果表明临床病料阳性率为40％，所有毒株均属于高致病性毒株。对PRRSV阳性病毒的Nsp2基因序列分析表明，所有18株PRRSV均属于美洲型毒株，与中国高致病性PRRSV代表毒株JXA1、WUH1的氨基酸同源性分别在82．2％～97．6％、80．4％～95.3％。此外，18株病毒的Nsp2共同存在不连续的30个氨基酸缺失，缺失位置与同期中国高致病性PRRSV具有相同的特征。通过本研究掌握了江苏地区2007～2010年间PRRSV流行情况及Nsp2基因变异特征，为地方猪繁殖与呼吸综合征的临床诊断和防治提供参考依据。

A RT-PCR to amplify the Nsp2 gene sequence of highly Pathogenic porcine reproductive and respiratory syndrome virus （PRRSV） was optimized with a pair of primers designed according to sequence published in GenBank. This RT-PCR method could differentiate classical PRRSVs and highly pathogenic PRRSVs. Clinical samples collected during 2007-2010 were detected with the RT-PCR and 40% samples（18/45） were positive for PRRSV, and all these viruses were similar to highly pathogenic PRRSV with deletion at Nsp2 region. The Nsp2 gene analysis revealed that the 18 strains belonged to North American genotype and the amino acids sequences showed 82.2%-97.6% and 80.4%-95.3% identity with JXA1 and WUH1 strains isol＇ated in China, respectively. The 30 amino acid discontinuous deletion was also found in the 18 positive viruses, which shared the same deletion position with the highly pathogenic PRRSV.