2016—2020年浙江地区猪圆环病毒2型分子流行病学分析  

Molecular epidemiological analysis of porcine circovirus type 2 in Zhejiang Province from 2016 to 2020

作　　者：徐丽华[1] 苏菲[1] 李军星[1] 余斌[1] 叶十一 杨富文[1] 邓利荣 毛慧敏 袁秀芳[1] XU Lihua;SU Fei;LI Junxing;YU Bin;YE Shiyi;YANG Fuwen;DENG Lirong;MAO Huimin;YUAN Xiufang(Institute of Animal Husbandry and Veterinary Science,Zhejiang Academy of Agricultural Sciences,Hangzhou 310021,China;Jiangshan Kangnong Agricultural Development Co.,Ltd.,Quzhou 324100,Zhejiang,China)

机构地区：[1]浙江省农业科学院畜牧兽医研究所,杭州310021 [2]江山康农农业发展有限公司,浙江衢州324100

出　　处：《浙江大学学报（农业与生命科学版）》2022年第5期644-652,共9页Journal of Zhejiang University:Agriculture and Life Sciences

基　　金：浙江省重点研发计划项目(2019C02052-3,2020C02011-05)。

摘　　要：为了解猪圆环病毒2型(porcine circovirus type 2,PCV2)在浙江地区的流行病学特点和遗传变异规律,本研究采用聚合酶链反应(polymerase chain reaction,PCR)对2016—2020年采自浙江省不同地区猪场的1725份疑似猪圆环病毒2型感染的临床病料进行PCV2的病原学检测,同时对部分阳性样品进行全基因组扩增、克隆和测序,并与GenBank中收录的16株参考株序列进行比对和遗传进化分析。结果表明:PCV2检测阳性的样品有359份,平均阳性率为20.8%,2016—2020年PCV2阳性率分别为38.1%、23.2%、24.1%、12.5%和10.7%;测序所得PCV236个全基因序列的核苷酸同源性为94.0%~99.9%,与国产疫苗株核苷酸同源性为94.7%~98.5%,与参考株核苷酸同源性为92.9%~99.8%;遗传进化分析显示PCV236个全基因序列可分为3个基因型,其中11株为PCV2a型,8株为PCV2b型,17株为PCV2d型,PCV2d为优势基因型;ORF2基因全长分别为705 bp(16株)和702 bp(20株),相互间核苷酸同源性为88.7%~100.0%,与国产疫苗株核苷酸同源性为90.2%~99.6%,与参考株核苷酸同源性为85.0%~100.0%。Cap蛋白的氨基酸序列分析表明,36株序列除了唯一糖基化位点呈高度保守外,存在较多的点突变,且不同基因型具有其代表性突变位点,优势基因型PCV2d的特异性突变位点主要集中在I^(53)、N^(68)、L^(89)、T^(121)、R^(168)、I^(215)。本研究为浙江地区PCV2的免疫预防提供了参考,为新型疫苗的研制积累了有效材料。In order to investigate the molecular epidemiology and genetic variation of porcine circovirus type 2(PCV2)in Zhejiang Province,a total of 1725 clinical samples suspected of PCV2 infection were collected from different regions of Zhejiang Province between 2016 and 2020.All these samples were subjected to pathogenic detection by polymerase chain reaction(PCR).The whole genomes of some positive samples were amplified,cloned and sequenced,and compared with sequences of 16 reference strains in the GenBank for genetic evolution analysis.The results showed that 359 samples were tested positive,with an average positive rate of 20.8%,and the positive rates from 2016 to 2020 were 38.1%,23.2%,24.1%,12.5%,and 10.7%,respectively.The whole genomes of 36 isolates were sequenced.Multiple sequence alignments showed that the nucleotide sequence homologies among 36 PCV2 strains were 94.0%−99.9%,while the homologies were up to 94.7%−98.5%compared with the domestic vaccine strains,and 92.9%−99.8%compared with the reference strains.The phylogenetic analysis showed that these 36 isolates belong to three genotypes,including 11 strains of PCV2a genotype,eight strains of PCV2b genotype and 17 strains of PCV2d genotype.Among these,PCV2d was the predominant genotype.The length of PCV2 ORF2 gene was 705 bp in 16 isolates and 702 bp in 20 isolates.The nucleotide sequence homologies of ORF2 gene among these 36 isolates were 88.7%−100.0%,while the homologies were 90.2%−99.6%compared with the domestic vaccine strains,and 85.0%−100.0%compared with the reference strains.The amino acid sequence analysis of Cap protein indicated a large number of point mutations in addition to the only highly conserved glycosylation site.Moreover,different genotypes had characteristic mutation sites,and the specific mutation sites of dominant genotype PCV2d were mainly concentrated in I^(53),N^(68),L^(89),T^(121),R^(168) and I^(215).This study provides a reference for the immune prevention of PCV2 in Zhejiang Province and accumulates effective materials

关 键 词：猪圆环病毒2型 全基因组 CAP蛋白 分子流行病学 遗传变异 

分 类 号：S855.3[农业科学—临床兽医学]