2020年新疆维吾尔自治区喀什市环境污水中首次分离到Ⅰ型疫苗衍生脊髓灰质炎病毒的早期应对

Early response to a typeⅠvaccine-derived poliovirus isolated from environmental sewage in Kashgar city of Xinjiang Uygur Autonomous Region in 2020

目的对新疆喀什市2020年9月环境污水中Ⅰ型疫苗衍生脊髓灰质炎(脊灰)病毒(Vaccine derived poliovirus,VDPV)分离株进行鉴定和早期应对。方法2020年9月-2021年6月在喀什市每月采集1-2份环境污水标本,2020年12月10-12日对环境污水覆盖区域内<5岁健康儿童采集粪便标本,进行脊灰病毒(Poliovirus,PV)分离,采用实时荧光定量PCR对PV分离株进行型内鉴定,分析VP_(1)区核苷酸序列变异,构建系统进化树以确定来源。结果在14份环境污水标本中11份标本分离到38株PV,在51份健康儿童粪便标本中2份标本分离到2株PV,其中2020年9月环境污水标本分离的1株PV的VP_(1)区有12个核苷酸变异,鉴定为I型VDPV,与中国既往或GenBank中Ⅰ型VDPV序列均不同源,之后连续7个月未再检出遗传学相关的VDPV,该分离株确定为未分类VDPV。结论本研究从喀什市环境污水中检出的I型VDPV来源不明确;环境监测有助于VDPV或脊灰野病毒的及时发现和早期应对。

Objective To describe early identification and response to a typeⅠvaccine-derived poliovirus(VDPV)isolated from environmental sewage in Kashgar,Xinjiang in September 2020.Methods We collected environmental sewage samples in Kashgar once or twice a month from September 2020 to June 2021 for surveillance and isolation of poliovirus(PV).During December 10 to 12,2020,we obtained fecal samples for PV isolation from 5-year-old healthy children residing in the areas covered by the environmental sewage surveillance.We used real-time quantitative PCR to conduct intratypic differentiation of isolated PVs,analyzed nucleotide sequence variations in VP_(1) regions,and constructed a phylogenetic tree to determine origins of isolates.Results Thirty-eight PV strains were isolated from 11 of 14 environmental sewage samples,and two PV strains were isolated from two of 51 fecal samples from healthy children.One PV isolate from environmental sewage in September 2020 had 12 nucleotide changes in the VP_(1) region and was identified as a typeⅠVDPV.The isolate was not homologous to any previous typeⅠVDPV strains from China or GenBank.No genetically related VDPVs were detected in the subsequent seven months.The isolate was confirmed to be an ambiguous VDPV(aVDPV).Conclusions The origin of a typeⅠVDPV isolated from environmental sewage in Kashgar was not able to be determined.Environmental surveillance is helpful for timely detection of and early response to VDPVs or wild polioviruses.