西宁市一起学校流行性腮腺炎暴发疫情流行病学和病原学特征分析

Analysis of epidemiological and pathogenic characteristics of a mumps outbreak in a school in Xining, Qinghai province

目的分析西宁市一起学校流行性腮腺炎(流腮)暴发疫情的流行病学和病原学特征。方法采用现场流行病学调查方法分析本起流腮疫情的三间分布特征;对9例流腮疑似病例采集血清和咽拭子标本进行实验室检测。腮腺炎病毒核酸阳性的咽拭子标本进行病毒分离。采用RT-PCR方法对病毒分离株SH基因进行扩增,鉴定和分析腮腺炎病毒的基因型别与基因特征。结果本起疫情共累计报告流腮疑似病例13例。病例主以7~11岁为主,集中在8岁(69.23%,9/13)。男女比例为1.6∶1。13例病例均无明确的腮腺炎疫苗接种史。本起疫情具有明显的班内聚集性。在采集标本的9例病例中有8例腮腺炎特异性IgM抗体和病毒核酸检测双阳性。获得2株阳性腮腺炎病毒分离物,经基因型鉴定均为F基因型,2株腮腺炎病毒SH基因序列同源性100%。结论本起疫情是一起由F基因型腮腺炎病毒引起的学校流腮暴发疫情,建议当地开展中小学腮腺炎疫苗的查漏补种工作。

Objective To investigate the epidemiological and pathogenic characteristics of a mumps outbreak in a primary school in Xining,Qinghai province.Methods The epidemiological investigation was carried out to analyze the epidemiological distribution of mumps cases in the outbreak.Serum and throat swab samples were collected from 9 suspected mumps cases for laboratory testing.The throat swab samples detected positive for nucleic acid of mumps virus were subjected to virus isolation.Then the SH gene was amplified by RT-PCR for positive virus isolates,and the genotypes of mumps virus were identified and gene characteristics were analyzed.Results A total of 13 cases were reported in this outbreak.The age of cases was mainly 7-11 years old,and the cases were mainly concentrated at 8 years old(69.23%.9/13).The male to female ratio is 1.6:1.None of the 13 cases had a history of mumps vaccination.And there was an obvious in-class clustering in this mumps outbreak.Of the 9 suspected mumps cases,8 were double positive for mumps specific IgM antibody and viral nucleic acid.Two positive mumps virus isolates were obtained and identified by genotyping as F genotype,and the SH gene sequence of the two mumps virus isolates had 100%homology.Conclusions This outbreak is caused by genotype F mumps virus.MuV immunization activities were recommended to conduct among unvaccinated students in primary and secondary schools.