湖北地区猪流行性腹泻病毒流行病学调查及N基因的序列分析

Epidemiological Investigation and Sequence Analysis of N Gene of Porcine Epidemic Diarrhea Virus In Hubei Province

为了解湖北地区猪流行性腹泻病毒(PEDV)的流行特征及变异情况。2021年3月-2022年2月,从湖北地区共收集腹泻症状的粪便-肛门棉拭子1580份,采用双重巢式PCR法进行检测,分析不同养殖阶段、季节间的感染差异;并选取部分阳性样品进行PEDV-N基因的扩增与遗传进化分析。1580份样品共检出阳性样品318份,阳性率为20.13%(318/1580)。其中0~28 d仔猪、28~70 d保育猪、70~120 d后备猪、120~270 d中大猪和>270 d猪只的阳性率分别为40.27%、26.89%、10.33%、8.07%和5.50%。冬季为PEDV感染的高发期(36.66%),其次是春季(19.00%)和秋季(11.49%),夏季(5.55%)的检出率相对较低。将部分阳性样品进行PEDV-N基因测序,随机挑选12株测序序列与24株参考株进行遗传进化分析,测序序列间N基因的核苷酸同源性为94.0%~99.7%,氨基酸同源性为93.9%~100.0%;测序序列与参考毒株的核苷酸同源性为94.5%~99.8%,氨基酸同源性为94.6%~100.0%。通过系统性发育进化树分析,PEDV流行株可分为三个亚型,G1-a、G1-b和G2-a型,其中2株属于G1-a型,1株属于G1-b型,其余均属于G2-a型。本研究结果为明确PEDV在湖北地区的流行特点及变异情况提供了参考依据。

To understand the epidemic characteristics and variation of porcine epidemic diarrhea virus in Hubei Province.A total of 1580 fecal-anal cotton swabs with diarrhea symptoms were collected from Hubei province from March 2021 to February 2022 detected by nested PCR to analyze the infection differences among different breeding stages and seasons,some positive samples were selected for amplifi cation and genetic evolution analysis of PEDV-N gene.A total of 318 positive samples were detected from 1580 samples,the positive rate was 20.13%(318/1580).The positive rates of 0~28 d piglets,28~70 d nursery pigs,70~120 d reserve pigs,120~270 d large pigs and>270 d pigs were 40.27%,26.89%,10.33%,8.07%and 50%,respectively.The highest incidence of PEDV infection(36.66%)in winter,followed by(19.00%)in spring and(11.49%)in autumn.The detection rate of PEDV infection was relatively low in summer at(5.55%).Partial positive samples were sequenced for PEDV-N gene,and 12 strains were randomly selected for genetic evolution analysis with 24 reference strains. The nucleotide homology of N gene and amino acid homology were 94.0%~99.7% and 93.9%~100.0%, respectively. The nucleotide homology and amino acid homology were 94.5%~99.8% and 94.6%~100.0% respectively. According to phylogenetic tree analysis, PEDV epidemic strains can be divided into three subtypes: G1-a, G1-b and G2-a, among them, 2 strains belong to G1-a, 1 strain belongs to G1-b, and the rest belong to G2-a. The results of this study provide a reference for clarifying the epidemic characteristics and variation of PEDV in a certain place in Hubei Province.