2015-2016年川南地区猪繁殖与呼吸综合征病毒遗传进化分析
Genetic Evolution of the ORF5 Gene of (PRRSV) in Sichuan, China from 2015 to 2016

猪繁殖与呼吸综合征病毒(PRRSV)主要引起母猪繁殖障碍与生长猪呼吸障碍性疾病，给养猪业造成严重损失.为了解川南地区2015-2016年PRRSV遗传变异情况，该研究收集了85份疑似感染PRRSV组织样品，通过RT-PCR扩增ORF5基因，对其进行克隆、序列测定和所测序列遗传进化分析.获得15个ORF5序列，其遗传距离与序列相似性为0.0~0.25和81.1%~100%.与VR2332，JXA1，NADC30和JX1411核酸序列相似性分别为83.4%~89.1%，83.4%~99.3%，81.9%~95.7%和81.4%~92.9%.进化树分析显示，15个ORF5序列形成3个亚群，8个ORF5序列与JXA1形成subcluster Ⅰ，5个与NADC30 like形成subcluster Ⅱ，2个与ZJ1503 like毒株形成subcluster Ⅲ.研究结果表明，该地区PRRSVs毒株基因型日趋复杂，建议通过合理疫苗免疫，减少通过重组导致出现复杂的PRRSV基因型，对PRRSV的防控具有重要意义.
Porcine reproductive and respiratory syndrome (PRRS) is considered to be the most widespread viral disease in industrial swine production. It leads to reproductive failure in pregnant sows and respiratory distress in young pigs. In order to research the genetic variation of porcine reproductive and respiratory syndrome virus (PRRSV) in Sichuan, China, eighty five clinical samples were collected and detected in 2015-2016. A total of fifteen ORF5 gene sequences were identified. Their pairwise-genetic distance and sequence homology were 0.00-0.25 and 81.1%-100%, respectively. These strains had 83.4%-89.1% identity with VR2332 at the nucleotide level and 82.1%-88.1% with amino acid level. What's more, those field sequences showed 83.4%-99.3% of nucleotide and 83.1%-99.5% of amino acid identity to JXA1 strain. In addition, those ORF5 gene sequences showed 81.9%-95.7% of nucleotide and 80.6%-94.5% of amino acid identity to the NADC30 strain. Moreover, those ORF5 gene sequences showed 81.4%-92.9% of nucleotide and 81.6%-92.5% of amino acid identity to the novel type PRRSV including JX1411 strain. Phylogenetic analysis revealed that the fifteen ORF5 gene sequences formed three subclusters. The first eight ORF5 genes and JXA1 belonged to subcluster Ⅰ, In addition, five of them were subclustered with NADC30 strain into subcluster Ⅱ, and the last two ORF5 gene sequences were subclustered with ZJ1503like to form a novel subcluster Ⅲ. The above results suggest that the genotypes of the PRRSV in this region are becoming increasingly complex. It is recommended that proper immune vaccination be used to reduce the complicated genotypes of the wild strains. That will be of great significance for the control and prevention of PRRSV