1例婴儿感染H9N2亚型禽流感病毒特征分析  

Characteristics of an avian influenza A （H9N2） virus isolated from an infant

作　　者：黄一伟[1] 陈柏塘[2] 张恒娇[1] 谢群[2] 李文超[1] 李成华[2] 张斯钰[1] 黄超洋[1] 邓志红[1] 张红[1] 

机构地区：[1]湖南省疾病预防控制中心,长沙410005 [2]郴州市疾病预防控制中心,423000

出　　处：《中华实验和临床病毒学杂志》2017年第5期419-423,共5页Chinese Journal of Experimental and Clinical Virology

基　　金：湖南省科技厅资助一般项目（2014SK3246）;湖南省卫生厅重点课题（A2011-006）

摘　　要：目的 对1株从11月龄感染人禽流感的婴儿中分离的H9N2亚型禽流感病毒进行全基因组特征分析,推测可能的感染来源.方法 从流感哨点监测医院采集流感样病例咽拭子标本,采用细胞分离方法分离流感病毒,对细胞分离物采用血凝试验、血凝抑制试验和荧光PCR的方法进行流感病毒的型别和亚型的鉴定,并对分离的病毒进行全基因组序列测序,对测定的核酸序列和推导的氨基酸序列采用生物信息学软件构建进化树进行比对分析.结果 从l例婴儿流感样病例采集的标本中分离到1株季节性流感无法分型的流感病毒,经过荧光PCR方法分型,确认为H9N2亚型禽流感病毒,病例确诊为人感染H9N2禽流感病例.流行病学调查显示,病例无明确的禽类接触史和暴露史.病毒经全基因组测序得到8条基因序列,Blast分析表明片段均为禽源,与湖南省活禽市场外环境中分离的H9N2亚型禽流病毒的核苷酸同源性为97.5％ ～99.8％,未发现与人流感病毒发生基因片段重配.病毒属于基因型G57,推导的氨基酸序列分子特征分析显示病毒为典型的禽类中H9N2亚型禽流感病毒特征.结论 虽然病例无明确的禽类接触史和暴露史,但分子溯源表明可能的感染来源仍为禽类.Objective To analyze the genome characteristics of an avian influenza A （H9N2） virus isolated from an 11-month-old infant,and to look for possible sources of infection.Methods Throat swabs were collected from an infant with influenza-like illness in influenza sentinel surveillance hospitals and isolated for influenza viruses using cells.The isolates were identified for influenza virus types and subtypes by the method of hemagglutination assay,hemagglutination inhibition assay and fluorescence PCR.Whole genome sequencing of the isolated virus was carried out.The genome nucleic acid sequences and the deduced amino acid sequences were analyzed by comparing the phylogenetic trees which were constructed by bioinformatics software.Results A seasonal un-typed influenza virus was isolated from the infant with influenza like illness.With fluorescent PCR method,it was identified as H9N2 subtype of avian influenza virus and the case was confirmed as a human infected with an avian influenza A （H9N2） virus.Epidemiological studies revealed that the case had no clear history of poultry contact and exposure.Blast analysis shows that eight segments of the viral genome are avian origin,and 97.5%-99.8% homology with that of viruses isolated from the live-poultry markets.The virus belongs to G57 genotype,deduced amino acid sequence analysis shows that the virus has typical low pathogenic avian influenza characteristics.Conclusions Although the case does not have a clear history of contact or exposure to poultry,molecular traceability suggests that possible sources of infection may be still from poultry.

关 键 词：禽流感 婴儿 H9N2 核苷酸序列 

分 类 号：R440[医药卫生—诊断学] R725.1[医药卫生—临床医学]