title: High seroprevalence of antibodies to avian influenza viruses among wild waterfowl in Alaska: implications for surveillance.
abstract: We examined seroprevalence (presence of detectable antibodies in serum) for avian influenza viruses (AIV) among 4,485 birds, from 11 species of wild waterfowl in Alaska (1998-2010), sampled during breeding/molting periods. Seroprevalence varied among species (highest in eiders (Somateria and Polysticta species), and emperor geese (Chen canagica)), ages (adults higher than juveniles), across geographic locations (highest in the Arctic and Alaska Peninsula) and among years in tundra swans (Cygnus columbianus). All seroprevalence rates in excess of 60% were found in marine-dependent species. Seroprevalence was much higher than AIV infection based on rRT-PCR or virus isolation alone. Because pre-existing AIV antibodies can infer some protection against highly pathogenic AIV (HPAI H5N1), our results imply that some wild waterfowl in Alaska could be protected from lethal HPAIV infections. Seroprevalence should be considered in deciphering patterns of exposure, differential infection, and rates of AIV transmission. Our results suggest surveillance programs include species and populations with high AIV seroprevalences, in addition to those with high infection rates. Serologic testing, including examination of serotype-specific antibodies throughout the annual cycle, would help to better assess spatial and temporal patterns of AIV transmission and overall disease dynamics.
authors.affiliation: United States Fish and Wildlife Service, Migratory Bird Management, Anchorage, Alaska, USA. heather_wilson@fws.gov
authors.forename: Heather M
authors.initials: HM
authors.lastname: Wilson
authors.forename: Jeffery S
authors.initials: JS
authors.lastname: Hall
authors.forename: Paul L
authors.initials: PL
authors.lastname: Flint
authors.forename: J Christian
authors.initials: JC
authors.lastname: Franson
authors.forename: Craig R
authors.initials: CR
authors.lastname: Ely
authors.forename: Joel A
authors.initials: JA
authors.lastname: Schmutz
authors.forename: Michael D
authors.initials: MD
authors.lastname: Samuel
mesh_terms: D000413:Alaska; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D004372:Ducks / Q000821:virology*; D005260:Female; D005777:Geese / Q000821:virology*; D005843:Geography; D053124:Influenza A Virus, H5N1 Subtype; D005585:Influenza in Birds / Q000453:epidemiology*; D008297:Male; D016017:Odds Ratio; D012044:Regression Analysis; D016036:Seroepidemiologic Studies; D013997:Time Factors
chemical_list: D000914:Antibodies, Viral