北京地区1起人副流感病毒1型感染暴发疫情分子流行特征

Molecular epidemiological characteristics of an outbreak caused by human parainfluenza virus type 1 in Beijing

目的对北京地区1起人副流感病毒(human parainfluenza viruses,HPIV)感染暴发疫情进行流行病学调查及病原学分析,为疫情防控提供科学依据。方法对北京地区某托幼机构发热病例开展现场流行病学调查分析,采集病例咽拭子标本,利用实时荧光定量聚合酶链反应进行病原筛查。对人副流感病毒1型(human parainfluenza viruses 1,HPIV1)检测阳性的样本核酸,扩增HN和F基因并测序,通过生物信息软件分析病毒的基因特征。结果本次疫情中12名患儿均有发热症状,部分患儿有咽痛(7/12)、咳嗽(5/12)、流涕(5/12)等症状。7名患儿HPIV1核酸阳性,其他病原体检测阴性。系统进化树显示,本次研究的毒株位于进化支2.3,其HN基因中有4个氨基酸特异取代位点(G5E、V22A、P29S、T68A),F基因中有3个氨基酸特异取代位点(N333S、T475K、I509M),与进化支2中的其他毒株不同。结论本次疫情由HPIV1引起,对其进行流行病学调查和病毒基因特征分析有助于疫情的溯源和防控。

Objective To conduct an epidemiological investigation and etiological analysis of an outbreak of human parainfluenza virus in Beijing,providing scientific evidence for the prevention and control of the epidemic.Methods A field epidemiological investigation was conducted on fever cases in kindergartens.Throat swab samples were collected from the cases,and real-time fluorescence quantitative polymerase chain reaction was used for pathogen screening.For samples that tested positive for human parainfluenza virus type 1(HPIV1),the HN and F genes were amplified and sequenced,and the genetic characteristics of the virus were analyzed using bioinformatics software.Results All the 12 children affected in this outbreak exhibited symptoms of fever,and additional symptoms included sore throat(7/12),cough(5/12),and runny nose(5/12).Seven children were positive for HPIV1 nucleic acid and negative for other pathogens.The phylogenetic tree showed that the strains in this study belonged to clade 2.3.There were four specific substitution sites(G5E,V22A,P29S,T68A)in the HN gene and three specific substitution sites(N333S,T475K,I509M)in the F gene of the strains,differentiating these strains from others within clade 2.Conclusions This outbreak was caused by HPIV1.The epidemiological investigation and genetic characteristics analysis of HPIV1 could help to trace the source of the outbreak and prevent it.