2017年福建地区PRRSV分子检测及ORF5基因变异分析

Molecular detection of PRRSV and variation analysis of ORF5 gene in Fujian province in 2017

【目的】研究2017年福建地区中小规模猪场猪繁殖与呼吸综合征病毒(PRRSV)毒株的分子流行情况。【方法】从福建地区中小规模猪场收集83份疑似蓝耳阳性病料,对编码GP5蛋白的ORF5基因进行了RT-PCR检测和遗传进化分析。【结果】采集的83份疑似蓝耳病料中阳性率为73%,测得的序列之间ORF5的核苷酸相似性达80.3%～100.0%,其中所测的各个分支毒株与其所属分支的代表毒株NADC30、GM2和JXA1的核苷酸相似性分别为92.6%～93.9%、89.8%～93.0%和93.4%～99.3%,检测到新分支中新出现的毒株与JXA1的核苷酸相似性为91.0～93.0%。GP5氨基酸比对结果显示不同亚群GP5信号肽区、诱导表位、主要中和表位及高变区等功能区发生了显著变异。【结论】福建地区出现了PRRSV新分支,使福建PRRSV变异种类更加多样化,建议加强PRRSV流行及变异的监测。

【Objective】To study the molecular prevalence of the porcine peproductive and respiratory syndrome virus (PRRSV) strain in small and medium-sized pig farms of Fujian province in 2017.【Method】 We collected 83 suspected blue ear positive disease materials from small and medium-sized pig farms in Fujian province. RT-PCR detection and genetic evolution analysis of ORF5 gene which encoded GP5 protein was performed.【Result】The positive rate of 83 suspected blue ear disease samples was 73%, and the nucleotide similarity among the measured ORF5 sequences was 80.3%~100.0%. The nucleotide similarities between tested strains of different branches and the representative strains of those branches, NADC30, GM2 and JXA1, were 92.6%~93.9%, 89.8%~93.0% and 93.4%~99.3%, respectively. The new identified strain in the new branch had nucleotide similarity of 91.0%~93.0% to JXA1. The GP5 amino acid alignment showed significant variation in functional regions such as GP5 signal peptide region, induction epitope, principal neutralizing epitope and hypervariable region in different subgroups.【Conclusion】A new branch of PRRSV has emerged in Fujian area, making the PRRSV variants in Fujian more diverse. It is necessary to strengthen the monitoring of PRRSV epidemics and mutations.