title: Unique reassortant of influenza A(H7N9) virus associated with severe disease emerging in Hong Kong.
abstract: OBJECTIVE
  Human infections caused by avian influenza virus A(H7N9) re-emerged in late 2013. We reported the first Hong Kong patient without risk factors for severe A(H7N9) disease.
  
  
  METHODS
  Direct sequencing was performed on the endotracheal aspirate collected from a 36-year-old female with history of poultry contact. Bioinformatic analysis was performed to compare the current strain and previous A(H7N9) isolates.
  
  
  RESULTS
  The influenza A/Hong Kong/470129/2013 virus strain was detected in a patient with acute respiratory distress syndrome, deranged liver function and coagulation profile, cytopenia, and rhabdomyolysis. The HA, NA and MP genes of A/Hong Kong/470129/2013 cluster with those of other human A(H7N9) strains. The PB1, PB2 and NS genes are most closely related to those of A/Guangdong/1/2013 strain identified in August 2013, but are distinct from those of other human and avian A(H7N9) strains. The other internal genes NP and PA genes are more closely related to those of non-A(H7N9) avian influenza A viruses. A unique PA L336M mutation, associated with increased polymerase activity, was found. The patient required salvage by extracorporeal membrane oxygenation.
  
  
  CONCLUSIONS
  The A/Hong Kong/470129/2013 virus is a novel reassortant derived from A/Guangdong/1/2013 virus. The unique mutation PA L336M may enhance viral replication and therefore disease severity.
authors.affiliation: State Key Laboratory for Emerging Infectious Diseases, Hong Kong Special Administrative Region; Carol Yu Centre for Infection, Hong Kong Special Administrative Region; Research Centre of Infection and Immunology, Hong Kong Special Administrative Region; Department of Microbiology, The University of Hong Kong, Hong Kong Special Administrative Region.
authors.forename: Kelvin Kai-Wang
authors.initials: KK
authors.lastname: To
authors.affiliation: Department of Microbiology, The University of Hong Kong, Hong Kong Special Administrative Region.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Song
authors.affiliation: Department of Microbiology, The University of Hong Kong, Hong Kong Special Administrative Region.
authors.forename: Siu-Ying
authors.initials: SY
authors.lastname: Lau
authors.affiliation: Department of Pathology, Tuen Mun Hospital, Hong Kong Special Administrative Region.
authors.forename: Tak-Lun
authors.initials: TL
authors.lastname: Que
authors.affiliation: Department of Pathology, Tuen Mun Hospital, Hong Kong Special Administrative Region.
authors.forename: David Christopher
authors.initials: DC
authors.lastname: Lung
authors.affiliation: Department of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region.
authors.forename: Ivan Fan-Ngai
authors.initials: IF
authors.lastname: Hung
authors.affiliation: State Key Laboratory for Emerging Infectious Diseases, Hong Kong Special Administrative Region; Carol Yu Centre for Infection, Hong Kong Special Administrative Region; Research Centre of Infection and Immunology, Hong Kong Special Administrative Region; Department of Microbiology, The University of Hong Kong, Hong Kong Special Administrative Region.
authors.forename: Honglin
authors.initials: H
authors.lastname: Chen
authors.affiliation: State Key Laboratory for Emerging Infectious Diseases, Hong Kong Special Administrative Region; Carol Yu Centre for Infection, Hong Kong Special Administrative Region; Research Centre of Infection and Immunology, Hong Kong Special Administrative Region; Department of Microbiology, The University of Hong Kong, Hong Kong Special Administrative Region. Electronic address: kyyuen@hku.hk.
authors.forename: Kwok-Yung
authors.initials: KY
authors.lastname: Yuen
mesh_terms: D000328:Adult; D016000:Cluster Analysis; D021821:Communicable Diseases, Emerging / Q000453:epidemiology* / Q000821:virology*; D019143:Evolution, Molecular; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D064766:Influenza A Virus, H7N9 Subtype / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D007251:Influenza, Human / Q000453:epidemiology* / Q000821:virology*; D008969:Molecular Sequence Data; D009154:Mutation; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics; D016865:Reassortant Viruses / Q000302:isolation & purification*; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D014132:Trachea / Q000821:virology; D014764:Viral Proteins / Q000235:genetics
chemical_list: C061290:PA protein, influenza viruses; D012367:RNA, Viral; D014764:Viral Proteins; D012324:RNA-Dependent RNA Polymerase
keywords: Avian influenza; Evolution; H7N9; L336M; PA; Phylogenetic tree