title: Evidence of the circulation of pandemic influenza (H1N1) 2009 with D222D/G/N/S hemagglutinin polymorphisms during the first wave of the 2009 influenza pandemic.
abstract: BACKGROUND
  The hemagglutinin HA1 D222G substitution may be associated with adverse outcomes in pandemic influenza A (H1N1) 2009 infections by enhancing the binding capacity of α2-3 sialyl receptors to pandemic influenza (H1N1) 2009 viruses.
  
  
  OBJECTIVE
  To investigate the emergence of the D222G mutation and other polymorphisms at this position during the first southern hemisphere pandemic wave in 2009.
  
  
  METHODS
  A total of 127 samples that were nucleic acid test positive for pandemic influenza (H1N1) 2009 virus were subjected to a sequence-based genotypic assessment of viral populations. Specimens showing polymorphisms at position 222 were further cloned to characterise the viral quasispecies.
  
  
  RESULTS
  A high proportion of intensive care unit (ICU) admissions (20%) and outpatients with mild symptoms (11.3%) carried polymorphisms of D/G/N/S at position 222 in hemagglutinin. Viral quasispecies derived from the upper and lower respiratory tract (URT and LRT) in ICU patients showed comparable levels of 222G populations.
  
  
  CONCLUSIONS
  The detection of 222G quasispecies present in the URT in both ICU and outpatient groups suggest ready transmission of these variants, and its frequent detection (and clusters) in outpatients imply local community transmission.
authors.affiliation: Center for Virus Research, Westmead Millennium Institute, University of Sydney, Australia. bin.wang@usyd.edu.au
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.forename: Dominic Edmund
authors.initials: DE
authors.lastname: Dwyer
authors.forename: Maly
authors.initials: M
authors.lastname: Soedjono
authors.forename: Haijing
authors.initials: H
authors.lastname: Shi
authors.forename: Kabo
authors.initials: K
authors.lastname: Matlho
authors.forename: Mala
authors.initials: M
authors.lastname: Ratnamohan
authors.forename: Christopher
authors.initials: C
authors.lastname: Blyth
authors.forename: Ken
authors.initials: K
authors.lastname: McPhie
authors.forename: Anthony Lawrence
authors.initials: AL
authors.lastname: Cunningham
authors.forename: Nitin Kumar
authors.initials: NK
authors.lastname: Saksena
mesh_terms: D019943:Amino Acid Substitution; D005260:Female; D006389:Hemagglutinins, Viral / Q000235:genetics*; D006801:Humans; D007231:Infant, Newborn; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics* / Q000302:isolation & purification* / Q000472:pathogenicity; D007251:Influenza, Human / Q000473:pathology / Q000635:transmission / Q000821:virology*; D007362:Intensive Care Units; D008875:Middle Aged; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D010045:Outpatients; D011110:Polymorphism, Genetic; D012367:RNA, Viral / Q000235:genetics; D017422:Sequence Analysis, DNA; D055815:Young Adult
chemical_list: D006389:Hemagglutinins, Viral; D012367:RNA, Viral; C458881:hemagglutinin fusogenic peptide, influenza virus