title: The Genomic Contributions of Avian H1N1 Influenza A Viruses to the Evolution of Mammalian Strains.
abstract: Among the influenza A viruses (IAVs) in wild aquatic birds, only H1, H2, and H3 subtypes have caused epidemics in humans. H1N1 viruses of avian origin have also caused 3 of 5 pandemics. To understand the reappearance of H1N1 in the context of pandemic emergence, we investigated whether avian H1N1 IAVs have contributed to the evolution of human, swine, and 2009 pandemic H1N1 IAVs. On the basis of phylogenetic analysis, we concluded that the polymerase gene segments (especially PB2 and PA) circulating in North American avian H1N1 IAVs have been reintroduced to swine multiple times, resulting in different lineages that led to the emergence of the 2009 pandemic H1N1 IAVs. Moreover, the similar topologies of hemagglutinin and nucleoprotein and neuraminidase and matrix gene segments suggest that each surface glycoprotein coevolved with an internal gene segment within the H1N1 subtype. The genotype of avian H1N1 IAVs of Charadriiformes origin isolated in 2009 differs from that of avian H1N1 IAVs of Anseriformes origin. When the antigenic sites in the hemagglutinin of all 31 North American avian H1N1 IAVs were considered, 60%-80% of the amino acids at the antigenic sites were identical to those in 1918 and/or 2009 pandemic H1N1 viruses. Thus, although the pathogenicity of avian H1N1 IAVs could not be inferred from the phylogeny due to the small dataset, the evolutionary process within the H1N1 IAV subtype suggests that the circulation of H1N1 IAVs in wild birds poses a continuous threat for future influenza pandemics in humans.
authors.affiliation: Department of Infectious Diseases, Division of Virology, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America.
authors.forename: Zeynep A
authors.initials: ZA
authors.lastname: Koçer
authors.affiliation: Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America.
authors.forename: Robert
authors.initials: R
authors.lastname: Carter
authors.affiliation: Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America.
authors.forename: Gang
authors.initials: G
authors.lastname: Wu
authors.affiliation: Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America.
authors.forename: Jinghui
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Infectious Diseases, Division of Virology, St. Jude Children's Research Hospital, Memphis, Tennessee, United States of America; Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Webster
mesh_terms: D000483:Alleles; D019943:Amino Acid Substitution; D000818:Animals; D019143:Evolution, Molecular; D005814:Genes, Viral; D016679:Genome, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000145:classification / Q000235:genetics* / Q000276:immunology; D010802:Phylogeny; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics; D016865:Reassortant Viruses / Q000235:genetics; D013552:Swine; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D014764:Viral Proteins / Q000235:genetics
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus; C108309:NS protein, influenza virus; C057027:PB2 protein, Influenzavirus A; D017361:Viral Nonstructural Proteins; D014764:Viral Proteins; D012324:RNA-Dependent RNA Polymerase