title: [Investigation on the source of the first human of avian influenza A (H5N1) case in Beijing].
abstract: OBJECTIVE
  To investigate the source of the first human case of avian influenza A (H5N1) infection in Beijing.
  
  
  METHODS
  Interviewing the relatives of the case and other key persons, collecting and detecting samples of related biological, epidemiological and environmental data of the case were conducted. Later, the infection source was thoroughly investigated.
  
  
  RESULTS
  The case ever contacted a slaughtered duck 5 days prior to the onset of illness, and the duck was bought from a stall of a wet market in Yanjiao area of Hebei province. Ten environmental samples were collected in this stall and the neighboring stall of the market. Another 6 samples were tested positive for H5N1 virus by PCR method, with 5 virus strains isolated. The whole-genome sequencing indicated that the amino acid homology between the H5N1 virus strains from the environment and the virus isolated from the case reached 99.8% - 100%.
  
  
  CONCLUSIONS
  From both epidemiological and virological evidence, it was proved that the first human case of avian influenza A (H5N1) infection in Beijing was infected by a duck that carrying H5N1 virus the case contacted 5 days proceeding the onset of illness.
authors.affiliation: Institute of Infectious and Endemic Diseases Control, Beijing Center for Disease Control and Prevention, Beijing 100013, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Yang
authors.forename: Jian
authors.initials: J
authors.lastname: Shi
authors.forename: Jian-xin
authors.initials: JX
authors.lastname: Ma
authors.forename: Xiu-jun
authors.initials: XJ
authors.lastname: Liu
authors.forename: Shun-xiang
authors.initials: SX
authors.lastname: Qi
authors.forename: Fang
authors.initials: F
authors.lastname: Huang
authors.forename: Wei-xian
authors.initials: WX
authors.lastname: Shi
authors.forename: Xiao-min
authors.initials: XM
authors.lastname: Peng
authors.forename: Yan-ning
authors.initials: YN
authors.lastname: Lv
authors.forename: Hui-jie
authors.initials: HJ
authors.lastname: Liang
authors.forename: Xin-yu
authors.initials: XY
authors.lastname: Li
authors.forename: Xiang-feng
authors.initials: XF
authors.lastname: Dou
authors.forename: Xiao-li
authors.initials: XL
authors.lastname: Wang
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xing-huo
authors.initials: XH
authors.lastname: Pang
authors.forename: Xiong
authors.initials: X
authors.lastname: He
authors.forename: Quan-yi
authors.initials: QY
authors.lastname: Wang
mesh_terms: D000328:Adult; D000818:Animals; D002681:China / Q000453:epidemiology; D004372:Ducks / Q000821:virology*; D005260:Female; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000453:epidemiology* / Q000821:virology*