title: Serological evidence for non-lethal exposures of Mongolian wild birds to highly pathogenic avian influenza H5N1 virus.
abstract: Surveillance for highly pathogenic avian influenza viruses (HPAIV) in wild birds is logistically demanding due to the very low rates of virus detection. Serological approaches may be more cost effective as they require smaller sample sizes to identify exposed populations. We hypothesized that antigenic differences between classical Eurasian H5 subtype viruses (which have low pathogenicity in chickens) and H5N1 viruses of the Goose/Guangdong/96 H5 lineage (which are HPAIV) may be used to differentiate populations where HPAIVs have been circulating, from those where they have not. To test this we performed hemagglutination inhibition assays to compare the reactivity of serum samples from wild birds in Mongolia (where HPAIV has been circulating, n = 1,832) and Europe (where HPAIV has been rare or absent, n = 497) to a panel of reference viruses including classical Eurasian H5 (of low pathogenicity), and five HPAIV H5N1 antigens of the Asian lineage A/Goose/Guangdong/1/96. Antibody titres were detected against at least one of the test antigens for 182 Mongolian serum samples (total seroprevalence of 0.10, n = 1,832, 95% adjusted Wald confidence limits of 0.09-0.11) and 25 of the European sera tested (total seroprevalence of 0.05, n = 497, 95% adjusted Wald confidence limits of 0.03-0.07). A bias in antibody titres to HPAIV antigens was found in the Mongolian sample set (22/182) that was absent in the European sera (0/25). Although the interpretation of serological data from wild birds is complicated by the possibility of exposure to multiple strains, and variability in the timing of exposure, these findings suggest that a proportion of the Mongolian population had survived exposure to HPAIV, and that serological assays may enhance the targeting of traditional HPAIV surveillance toward populations where isolation of HPAIV is more likely.
authors.affiliation: Wildlife Conservation Society, 2300 Southern Blvd, Bronx, NY, 10460, United States of America; Boyd Orr Centre for Population and Ecosystem Health, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, United Kingdom.
authors.forename: Martin
authors.initials: M
authors.lastname: Gilbert
authors.affiliation: Department of Viroscience, Erasmus Medical Center, 3015GE, Rotterdam, The Netherlands.
authors.forename: Björn F
authors.initials: BF
authors.lastname: Koel
authors.affiliation: Department of Viroscience, Erasmus Medical Center, 3015GE, Rotterdam, The Netherlands.
authors.forename: Theo M
authors.initials: TM
authors.lastname: Bestebroer
authors.affiliation: Department of Zoology, University of Cambridge, Cambridge, CB2 3EJ, United Kingdom.
authors.forename: Nicola S
authors.initials: NS
authors.lastname: Lewis
authors.affiliation: Department of Zoology, University of Cambridge, Cambridge, CB2 3EJ, United Kingdom.
authors.forename: Derek J
authors.initials: DJ
authors.lastname: Smith
authors.affiliation: Department of Viroscience, Erasmus Medical Center, 3015GE, Rotterdam, The Netherlands.
authors.forename: Ron A M
authors.initials: RA
authors.lastname: Fouchier
mesh_terms: D000818:Animals; D000835:Animals, Wild / Q000097:blood / Q000276:immunology / Q000821:virology; D000914:Antibodies, Viral / Q000097:blood / Q000276:immunology; D001717:Birds / Q000097:blood / Q000276:immunology / Q000821:virology*; D006385:Hemagglutination Inhibition Tests; D053124:Influenza A Virus, H5N1 Subtype / Q000276:immunology / Q000302:isolation & purification*; D005585:Influenza in Birds / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology; D008986:Mongolia / Q000453:epidemiology; D016036:Seroepidemiologic Studies
chemical_list: D000914:Antibodies, Viral