河北省猪繁殖与呼吸综合征病毒遗传变异分析

Genetic Variation Analysis of Porcine Reproductive and Respiratory Syndrome Virus in Hebei Province

为了解河北省猪群中猪繁殖与呼吸综合征病毒(PRRSV)的流行情况及毒株遗传变异趋势,应用RTPCR方法,对河北省10个地区的18个发病猪场进行调查,分别扩增出23株缺失部分NSP2基因和完整ORF5基因的毒株。序列分析结果显示,23株PRRSV NSP2基因均缺失了不连续的30个氨基酸,从而证实河北省存在美洲型PRRSV变异株的流行。23株PRRSV ORF5核苷酸序列与国内外已发表的基因序列绘制的遗传进化树表明:20个毒株与JXA1形成一个基因亚群;而另3个毒株与NADC30毒株形成一个基因亚群,并且变异最大,是以后的主要临床研究对象。推导编码氨基酸的比较结果表明,河北省流行的PRRSV毒株ORF5基因编码蛋白已发生较大变异,需在今后临床诊断与疫苗防控中引起重视。

In order to recognize the prevalence status of Porcine reproductive and respiratory syndrome virus（PRRSV）and its genetic variation trend in pigs in Hebei Province,the 18 pig farms that were attacked by PRRSV in 10 areas were investigated. Applying the RT-PCR,a total of 23 virus strains with partial loss of NSP2 gene and complete loss of ORF5 gene were identified. The sequence analysis results showed that all the 23 strains exhibited a 30 discrete amino acid deletion,confirming the prevalence situation of PRRSV variant strain of America type in Hebei Province. According to the phylogenetic tree of ORF5 gene drew by reference to the 23 isolates and the gene sequences published in and outside China,there were 20 isolates belonging to the subgroup that included JXA1 strain,and the other 3 isolates belonged to the subgroup that included DADC30 strain. With the largest variability,the latter 3 isolates would be the main objects of future clinical research. At last,the comparison results of amino acid showed there was much variation in the protein encoded by ORF5 gene in the prevalent PRRSV strain in Hebei Province,therefore more attention should be raised in the process of PRRS future clinical diagnosis and prevention and control by vaccine.