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目的描述山西省2007年Ⅰ型疫苗衍生脊髓灰质炎(脊灰)病毒(Vaccine-derived Poliovirus,VDPV)的基因特征,分析该VDPV的来源及对当地维持无脊灰的影响。方法对山西省2007年1例急性弛缓性麻痹(Acute Flaccid Paralysis,AFP)病例采集的双份粪便标本进行病毒分离,并对分离到的脊灰病毒(CHN11061株)进行VP1编码区基因核苷酸序列测定和分析,然后与国内外报道的其它Ⅰ型VDPV构建亲缘进化树。结果从该AFP病例的双份粪便标本中分离到2株Ⅰ+Ⅱ+Ⅲ混合型脊灰病毒,其中Ⅰ型毒株的VP1编码区基因核苷酸序列与PⅠ/赛宾(Sabin)疫苗株相比变异率≥1.0%,根据世界卫生组织(WHO)的标准鉴定为Ⅰ型VDPV。VP1编码区基因进化树图表明,山西省2007年Ⅰ型VDPV与国内外至今发现的其它VDPV进化距离较远,是新发现的VDPV,不属于循环着的(Circulating)VDPV(cVDPVs),同时无证据证明患儿为免疫缺陷患者,因此将这2株VDPV归类为Ⅰ型未分类的(Ambiguous)VDPV(aVDPV)。结论结合山西省2007年Ⅰ型VDPV的基因特征和当地口服脊灰减毒活疫苗(Oral Poliomylitis Attenuated Live Vaccine,OPV)免疫覆盖率情况,推测在当地存在1例免疫缺陷患者,由他/她长期携带并向外排泄变异的脊灰病毒,引起了山西省2007年VDPV感染事件。在脊灰消灭后期,应加强对可能存在的长期排毒者的发现和管理。
Objective To describe the genotypes of the 2007 Viral Vaccine-derived Poliovirus (VDPV) in Shanxi Province and analyze the origin of the VDPV and its impact on the maintenance of poliovirus-free in Shanxi Province. Methods The double stool samples collected from one case of Acute Flaccid Paralysis (AFP) in Shanxi Province in 2007 were isolated and the nucleotide sequences of the VP1 coding region of the isolated poliovirus (CHN11061) Sequencing and analysis, and then phylogenetic tree was constructed with other type VDPV reported at home and abroad. Results Two strains of mixed poliovirus type Ⅰ + Ⅱ + Ⅲ were isolated from two stool samples of AFP. The nucleotide sequence of the VP1 coding region of type Ⅰ strain was identical to that of the PⅠ / Sabin vaccine strain Compared with the mutation rate≥1.0%, it was identified as type V VDPV according to the standard of the World Health Organization (WHO). The phylogenetic tree of VP1 coding region showed that the VDPV type Ⅰ was found in Shanxi province in 2007 and far from the other VDPVs found in China and abroad. It is a newly found VDPV and does not belong to circulating VDPV (cVDPVs) Evidence for children with immunodeficiency evidenced that the two VDPVs were classified as type I (Ambiguous) VDPV (aVDPV). Conclusion Based on the genetic characteristics of type Ⅰ VDPV in Shanxi Province in 2007 and the oral coverage rate of Oral Poliomyelitis in live attenuated oral vaccine (OPV) in our country, it is speculated that there is one case of immunodeficiency in China. Carrying and excreting the mutated poliovirus caused the VDPV infection in Shanxi Province in 2007. In the latter part of polio eradication, the detection and management of possible long-term detoxification should be strengthened.