title: Antibody responses to avian influenza viruses in wild birds broaden with age.
abstract: For viruses such as avian influenza, immunity within a host population can drive the emergence of new strains by selecting for viruses with novel antigens that avoid immune recognition. The accumulation of acquired immunity with age is hypothesized to affect how influenza viruses emerge and spread in species of different lifespans. Despite its importance for understanding the behaviour of avian influenza viruses, little is known about age-related accumulation of immunity in the virus's primary reservoir, wild birds. To address this, we studied the age structure of immune responses to avian influenza virus in a wild swan population (Cygnus olor), before and after the population experienced an outbreak of highly pathogenic H5N1 avian influenza in 2008. We performed haemagglutination inhibition assays on sampled sera for five avian influenza strains and show that breadth of response accumulates with age. The observed age-related distribution of antibody responses to avian influenza strains may explain the age-dependent mortality observed during the highly pathogenic H5N1 outbreak. Age structures and species lifespan are probably important determinants of viral epidemiology and virulence in birds.
authors.affiliation: Department of Zoology, University of Oxford, Oxford OX1 3PS, UK.
authors.forename: Sarah C
authors.identifier: 0000-0002-2995-2596
authors.initials: SC
authors.lastname: Hill
authors.affiliation: Department of Virology, Animal and Plant Health Agency (APHA), Weybridge KT15 3NB, UK.
authors.forename: Ruth J
authors.initials: RJ
authors.lastname: Manvell
authors.affiliation: Department of Zoology, University of Oxford, Oxford OX1 3PS, UK.
authors.forename: Bodo
authors.initials: B
authors.lastname: Schulenburg
authors.affiliation: Department of Virology, Animal and Plant Health Agency (APHA), Weybridge KT15 3NB, UK.
authors.forename: Wendy
authors.initials: W
authors.lastname: Shell
authors.affiliation: Department of Zoology, University of Oxford, Oxford OX1 3PS, UK.
authors.forename: Paul S
authors.initials: PS
authors.lastname: Wikramaratna
authors.affiliation: Edward Grey Institute, Department of Zoology, University of Oxford, Oxford OX1 3PS, UK.
authors.forename: Christopher
authors.initials: C
authors.lastname: Perrins
authors.affiliation: Edward Grey Institute, Department of Zoology, University of Oxford, Oxford OX1 3PS, UK.
authors.forename: Ben C
authors.initials: BC
authors.lastname: Sheldon
authors.affiliation: Department of Virology, Animal and Plant Health Agency (APHA), Weybridge KT15 3NB, UK.
authors.forename: Ian H
authors.initials: IH
authors.lastname: Brown
authors.affiliation: Department of Zoology, University of Oxford, Oxford OX1 3PS, UK oliver.pybus@zoo.ox.ac.uk.
authors.forename: Oliver G
authors.initials: OG
authors.lastname: Pybus
mesh_terms: D000375:Aging; D000818:Animals; D000835:Animals, Wild; D046090:Anseriformes / Q000276:immunology* / Q000821:virology; D000914:Antibodies, Viral / Q000097:blood; D000917:Antibody Formation; D006385:Hemagglutination Inhibition Tests; D056724:Immunity, Humoral; D053124:Influenza A Virus, H5N1 Subtype; D005585:Influenza in Birds / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral
keywords: age; avian influenza; bird; immunity; lifespan; virus