河南省2016-2017年致病性猪圆环病毒遗传演化分析

Phylogenetic analysis of prevailing pathogenic porcine circovirus in Henan province during 2016-2017

采集了2016—2017年间不同地区临床疑似圆环病毒病病例样本65份，提取病毒核酸后，分别用PCV2和PCV3特异性引物进行PCR扩增，鉴定出PCV2阳性样品43份，阳性率为66．15％；PCV3阳性样品3份，阳性率为4．61％。选取其中13份PCV2阳性样品和3份PCV3阳性样品进行ORF2基因克隆、测序和进化分析。结果显示：河南省PCV2和PCV3流行毒株ORF2基因序列主要存在是单个碱基突变，没有缺失或插入。进化树分析显示，PCV2流行毒株均处于2b和2d2个基因群，其中7份属于2b型，6份属于2d型，2016年和2017年PCV2基因型并没有明显差别；3份PCV3阳性样品中KF-PCV3、AY—PCV3处于一个分支，SX-PCV3与MF589108形成一个分支。结果表明：2016—2017年间河南省感染和流行的PCV2主要为2b和2d2个基因群，表现出遗传进化稳定性，部分地区出现PCV3感染的情况。

In order to determine the genotype and genetic variation of pathogenic porcine circovirus （PCV） in partial region of Henan province, 65 suspected cases of porcine circovirus disease from different region of Henan province were collected during 2016--2017. The gene fragments were amplified by PCR with the specific primers of PCV2 and PCV3 . There were 43 PCV2 positive samples with positive rate of 66.15% and 3 PCV3 positive samples with positive rate of 4.61%. 13 PCV2 positive samples and 3 PCV3 positive samples were selected for cloning,sequencing and sequence analysis of ORF2 gene. Sequence alignment showed that variation among 16 samples was small and there wasonly single point mutations,no insertion or deletion changes. The phylogenetic analysis based on nucleotide sequence of ORF2 showed that 13 PCV2 were classified into two genotypes （7 PCV2b and 6 PCV2d） ,indicating that PCV2b and PCV2d were the predominant epidemic strains in Henan. Among the three PCV3 positive samples,KF-PCV3 and AY-PCV3 belonged to the same branch,and SX-PCV3 located in the branch with MF589108. Moreover,there were no significant difference in PCV2 genotype between 2016 and 2017 and showing genetic stability. PCV3 was detected in parts region of Henan province.