为了解我国川渝地区猪繁殖与呼吸综合征病毒(porcine reproductive and respiratory syndrome virus,PRRSV)的流行情况及分子特征,本试验以RT-PCR方法对2021-2022年间收集的来自川渝地区的临床样本进行PRRSV检测,并进一步对阳性样本的ORF5基因进行测序分析,探究其流行现状以及遗传变异情况.结果显示,川渝两地PRRSV阳性率为20.5％(40/195),其中四川PRRSV阳性率为18.1％(15/83),重庆为22.3％(25/112).对其中23份阳性样本的ORF5基因分析显示,所获PRRSV均为基因Ⅱ型,包含谱系1、3、5和8,以NADC30类毒株为主;其中四川地区毒株与上海、辽宁、湖南等地区毒株存在较近的亲缘关系,重庆地区与当地毒株的同源性较高;与 目前临床中使用的疫苗毒株比较,发现23株临床样本ORF5序列中有3个B细胞表位和1个T细胞表位与疫苗株存在较大差异.本试验结果表明PRRSV感染在川渝部分地区仍较为严重,美洲型NADC30类毒株是当前流行的优势毒株,且与疫苗株存在一定的变异,该结果对川渝地区PRRSV的防控具有借鉴意义.
Molecular epidemiology and ORF5 genetic characteristics of PRRSV in clinical samples in Sichuan and Chongqing during 2021-2022
To investigate the prevalence and molecular characteristics of porcine reproductive and respiratory syndrome virus(PRRSV)in Sichuan and Chongqing regions of China,clinical samples were collected from some areas of Sichuan and Chongqing during 2021 to 2022,and PRRSV was detected by PCR method.In addition,the ORF5 gene of positive samples was cloned and sequenced to explore its epidemic status and genetic variation.The results showed that the positive rates of PRRSV were 18.1％(15/83)and 22.3％(25/112)in Sichuan and Chongqing,respectively.The ORF5 gene analysis of 23 positive samples showed that all PRRSVs obtained were genotype Ⅱ,in-cluding lineages 1,3,5,and 8,with NADC30 like strain being the main strain;Among them,the strains in Sichuan region were closely related to strains in Shanghai,Liaoning,Hunan,and other regions in China,while the strains in Chongqing region had higher homology with local strains.Compared with the vaccine strains currently used in clinical practice,it was found that there were three B cell epitopes and one T cell epitope in the ORF5 sequence of 23 clinical samples that differ significantly from the vaccine strains.The results of this experiment indicated that PRRSV infection was still relatively severe in some areas of Sichuan and Chongqing.What's more,NADC30 like strain was the dominant strain in that area.Our results have reference significance for the pre-vention and control of PRRSV in Sichuan and Chongqing regions.
porcine reproductive and respiratory syndrome virusmolecular epidemiologyORF5 genegenetic variation analysis
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