2021-2022年湖南省PRRSV流行病学调查及基因组特征分析
Epidemiological survey and genomic characteristics of PRRSV in Hunan during 2021-2022
周宇骏 1龙明英 1孟芳 2王文梅 3邹玖零 4廖淑玲 1杜雅萍 1禹思宇2
作者信息
- 1. 湖南中科基因技术有限公司,湖南长沙 410128
- 2. 长沙海关技术中心,湖南长沙 410004
- 3. 宁乡市动物疫病预防控制中心,湖 南宁乡 410600
- 4. 永州市动物疫病预防控制中心,湖南永州 425100
- 折叠
摘要
[目的]了解当前湖南省猪繁殖与呼吸综合征病毒(PRRSV)流行情况及主要流行基因型占比情况,并明确其遗传进化关系及重组特征,为湖南省PRRS的科学防控提供参考依据.[方法]2021年3月—2022年10月,从湖南省14个市(州)396个疑似暴发PRRS的猪场采集1184病料样品,采用荧光定量PCR检测PRRSV阳性率,统计不同季节和不同地区的感染情况;利用RT-PCR扩增部分阳性病料样品ORF5序列后进行序列相似性及遗传进化分析;将部分病料接种Marc-145细胞进行病毒分离,采用二代测序技术完成全基因序测序后进行遗传进化分析,并以SimPlot分析是否发生组重组事件.[结果]共有167份病料样品检测结果呈PRRSV阳性(检出率14.1%),湖南省不同地区和不同季节的PRRSV样品阳性率分别为0～46.43%和6.95%～19.67%;高致病性PRRSV(HP-PRRSV)株、经典型PRRSV株和类NADC30株的占比分别为43.11%、15.57%和41.32%.共扩增获得21株PRRSV的完整ORF5序列(600～603 bp),其中,7株与HP-PRRSV参考株的GP5氨基酸序列相似性较高(92.1%～98.9%),13株与类NADC30株的相似性较高(91.3%～93.4%);1株与PRRSV经典株的相似性较高(98.6%～99.1%).不同PRRSV的GP5氨基酸序列变异程度高,其中2株类NADC30株GP5氨基酸序列高变区存在氨基酸残基缺失,且部分病毒株氨基酸变异区域位于GP5氨基酸序列的细胞表位区域.共分离获得2株PRRSV(HuN-A和HuN-B),其中,HuN-A株属于类NADC30株,且以类NADC30株为主要亲本株,以HP-PRRSV株为次要亲本株;HuN-B株属于类HP-PRRSV株.[结论]湖南省PRRSV流行情况较严重,且PRRSV流行株基因型繁多,其中类NADC30株和HP-PRRSV株属于主要流行基因型.分离获得的2株PRRSV中,HuN-A株是类NADC30株与类HP-PRRSV株(JXA1)间发生重组变异而来,HuN-B株可能是JXA1弱毒疫苗株出现毒力返祖而产生.
Abstract
[Objective]To investigate the epidemiological characteristics and genotype proportion of porcine reproduc-tive and respiratory syndrome virus(PRRSV)in Hunan Province,which will provide reference for the prevention and control of PRRS in Hunan province.[Method]1184 tissue samples of pigs suspected of PRRSV infection were collected from 396 pig farms in Hunan Province from 2021 to 2022,and the positive rates of different genotypes were determined by fluorescence quantitative RT-PCR,and the PRRSV infection rates in different regions and seasons were counted.The ORF5 sequences of some positive samples were amplified by RT-PCR,and their sequence homology and genetic features were analyzed.Furthermore,the supernatant of some PRRSV-positive sample was incubated with Marc-145 cells for viral isolation,and the complete genomes of PRRSV strains were amplified using the Illumina technology for genetic evolution analysis,the SimPlot software was employed to identify the potential recombinant events occurred in the viral genome.[Result]167 tissue samples(14.1%)were PRRSV-positive,the positive rate of PRRSV in different regions and seasons were 0.0%～46.4%and 6.95%～19.67%,respectively.Moreover,the proportions of highly pathogenic PRRSV(HP-PRRSV),classical PRRSV and NADC30-like strains were 43.11%,15.57%,and 41.32%,respectively.A total of 21 complete ORF5 gene sequences(600 bp～603 bp)were obtained in this study,the homology analysis showed that 7 strains had the highest homology(92.1%～98.9%)with the reference HP-PRRSV strains;13 strains showed the highest amino acid sequence identities(91.3%～93.4%)with the reference NADC30-like strains;only one strain were genetically identified with the classical PRRSV strains,with the sequence identities of 98.6%～99.1%.The amino acid sequence align-ment analysis showed that the amino acid sequence variation rate of different PRRSV GP5 remained high,and the GP5 hypervariable regions of two NADC30-like strains had amino acid deletion,and the amino acid variation regions of some PRRSV strains were mainly located in the GP5 cell epitope region.Two PRRSV strains(named HuN-A and HuN-B)were isolated.The whole genome sequence analysis results showed that HuN-A strain belonged to the NADC30-like strain in subgenotype 1.5,and which was a recombinant virus with NADC30 strain as the main parent and HP-PRRSV strain as the secondary parent;However,the HuN-B strain belongs to HP-PRRSV strain.[Conclusion]This study revealed the se-vere prevalence of PRRSV in pig populations in Hunan Province,where PRRSV strains were divided into several geno-types.Among which the NADC30 and HP-PRRSV strains are the dominant genotypes.Two PRRSV strains were success-fully isolated here,the HuN-A strain was recombinant from the NADC30-like strain and the HP-PRRSV like strain(JXA1),while the HuN-B strain might be derived from the JXA1 attenuated vaccine strain,owing to the virulence re-gression.
关键词
猪繁殖与呼吸综合征病毒(PRRSV)/流行病学调查/ORF5基因/重组分析/湖南省Key words
porcine reproductive and respiratory syndrome virus(PRRSV)/epidemiological investigation/ORF5 gene/virus isolation/recombination analysis/Hunan引用本文复制引用
基金项目
湖南省自然科学基金—科教联合项目(2021JJ60091)
出版年
2023
国家科技期刊平台
NSTL
万方数据