title: Molecular characterization and comparative analysis of pandemic H1N1/2009 strains with co-circulating seasonal H1N1/2009 strains from eastern India.
abstract: During the peak outbreak (July-September 2009), a total 1886 patients were screened in eastern India, of which 139 (7.37%) and 52 (2.76%) were positive for pH1N1 and seasonal H1N1, respectively. Full-length HA1, NA, NS1 and PB1-F2 genes of representative strains were sequenced. Phylogenetic analysis of deduced amino acid sequences of pH1N1 strains revealed HA1 and NS1 to be of North American swine lineage, and the NA gene of Eurasian swine lineage. Consistent with previous reports, the PB1-F2 gene of pH1N1 strains was unique due to a mutation resulting in a truncated protein of 11 aa. The HA, NA and NS1 genes of H1N1/2009 strains clustered with H1N1 strains of 2000-2009, whereas a subset of strains contained a pH1N1-like truncated PB1-F2. The truncated PB1-F2 may confer the advantage of lower pathogenicity but higher replication and infectivity to the human H1N1 strains. This is the first report of seasonal H1N1/2009 strains with a pH1N1/2009-like gene segment.
authors.affiliation: Division of Virology, National Institute of Cholera and Enteric Diseases, P-33 C.I.T. Road, Scheme XM, Beliaghata, Kolkata, West Bengal, India.
authors.forename: Mehuli
authors.initials: M
authors.lastname: Sarkar
authors.forename: Anurodh S
authors.initials: AS
authors.lastname: Agrawal
authors.forename: Rakhi
authors.initials: R
authors.lastname: Sharma Dey
authors.forename: Shiladitya
authors.initials: S
authors.lastname: Chattopadhyay
authors.forename: Ranajoy
authors.initials: R
authors.lastname: Mullick
authors.forename: Papiya
authors.initials: P
authors.lastname: De
authors.forename: Sekhar
authors.initials: S
authors.lastname: Chakrabarti
authors.forename: Mamta
authors.initials: M
authors.lastname: Chawla-Sarkar
mesh_terms: D000595:Amino Acid Sequence; D005814:Genes, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics; D006801:Humans; D007194:India / Q000453:epidemiology; D053118:Influenza A Virus, H1N1 Subtype / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity; D007251:Influenza, Human / Q000453:epidemiology* / Q000821:virology*; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D009154:Mutation; D009439:Neuraminidase / Q000235:genetics; D058873:Pandemics; D010802:Phylogeny; D012621:Seasons; D017386:Sequence Homology, Amino Acid; D017361:Viral Nonstructural Proteins / Q000235:genetics; D014764:Viral Proteins / Q000235:genetics
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus; C085820:INS1 protein, influenza virus; C442816:PB1-F2 protein, Influenza A virus; D017361:Viral Nonstructural Proteins; D014764:Viral Proteins; C483468:hemagglutinin, human influenza A virus; C487630:NA protein, influenza A virus; D009439:Neuraminidase