Science China Life Sciences

, Volume 56, Issue 6, pp 485–492 | Cite as

Environmental connections of novel avian-origin H7N9 influenza virus infection and virus adaptation to the human

  • Jun Li
  • XinFen Yu
  • XiaoYing Pu
  • Li Xie
  • YongXiang Sun
  • HaiXia Xiao
  • FenJuan Wang
  • Hua Din
  • Ying Wu
  • Di Liu
  • GuoQiu Zhao
  • Jun Liu
  • JingCao Pan
Open Access
Cover Article

Abstract

A novel H7N9 influenza A virus has been discovered as the causative identity of the emerging acute respiratory infection cases in Shanghai, China. This virus has also been identified in cases of infection in the neighboring area Hangzhou City in Zhejiang Province. In this study, epidemiologic, clinical, and virological data from three patients in Hangzhou who were confirmed to be infected by the novel H7N9 influenza A virus were collected and analyzed. Human respiratory specimens and chicken feces from a contacted free market were tested for influenza virus by real-time reverse transcription PCR (RT-PCR) and sequencing. The clinical features of the three cases were similar featured with high fever and severe respiratory symptoms; however, only one of the patients died. A certain degree of diversity was observed among the three Hangzhou viruses sequenced from human samples compared with other reported H7N9 influenza A viruses. The sequences of the novel avian-origin H7N9 influenza viruses from Hangzhou City contained important amino acid substitutions related to human adaptation. One of the Hangzhou viruses had gained a novel amino acid substitution (Q226I) in the receptor binding region of hemagglutinin. More importantly, the virus sequenced from the chicken feces had a 627E substitution in the PB2 protein instead of the mammalian-adapted 627K substitution that was found in the PB2 proteins from the Hangzhou viruses from the three patients. Therefore, the newly-emerging H7N9 virus might be under adaptation pressure that will help it “jump” from avian to human hosts. The significance of these substitutions needs further exploration, with both laboratory experiments and extensive field surveillance.

Keywords

H7N9 influenza A virus human adaptation epidemiology substitution 

Supplementary material

11427_2013_4491_MOESM1_ESM.pdf (193 kb)
Supplementary material, approximately 193 KB.

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Copyright information

© The Author(s) 2013

Authors and Affiliations

  • Jun Li
    • 1
  • XinFen Yu
    • 1
  • XiaoYing Pu
    • 1
  • Li Xie
    • 1
  • YongXiang Sun
    • 2
  • HaiXia Xiao
    • 5
  • FenJuan Wang
    • 2
  • Hua Din
    • 1
  • Ying Wu
    • 3
  • Di Liu
    • 3
    • 6
  • GuoQiu Zhao
    • 1
  • Jun Liu
    • 3
    • 4
  • JingCao Pan
    • 1
  1. 1.Hangzhou Center for Disease Control and PreventionHangzhouChina
  2. 2.Xiaoshan Center for Disease Control and PreventionHangzhouChina
  3. 3.CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of MicrobiologyChinese Academy of SciencesBeijingChina
  4. 4.National Institute for Viral Disease Control and PreventionChinese Center for Disease Control and PreventionBeijingChina
  5. 5.Laboratory of Protein Engineering and Vaccine, Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjinChina
  6. 6.Network Information Center, Institute of MicrobiologyChinese Academy of SciencesBeijingChina

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