Antibody prevalence to avian influenza virus subtypes H5, H7 and H9 in falcons, captive and wild birds, United Arab Emirates, 2003–2006

Abstract

Background: Avian influenza viruses (AIV) may cause enormous economic losses in the poultry industry and sporadically severe disease in humans. Falconry is a tradition of great importance in the Arabian Peninsula. Falcons may catch AIV through contact with infected quarry species.Objectives: Falcons together with other bird species are the focus of this seroprevalence study, carried out on sera collected in the United Arab Emirates (UAE). AIV with the haemagglutinin subtypes H5, H7 and possibly H9 may infect humans. Methods:We investigated the antibody prevalence to these subtypes in falcons and other birds by haemagglutination inhibition test. 617 sera of falcons and 429 sera of 46 wild/captive bird species were tested. Results:From the falcons, only one was positive for H5 antibodies (0.2%), none contained antibodies to H7, but 78 had antibodies to H9 (13.2%). Regarding other birds, eight were positive for antibodies to H5 (2.1%), none had antibodies to H7, but 55 sera from 17 species contained antibodies to H9 (14.4%). Conclusions:In contrast to H5 and H7 infections, H9N2 is widespread worldwide. Its ability to reassort, thereby creating possibly pathogenic strains for humans, should remind us of the potential risk that close contact with birds entails.

First Report of Low Pathogenic Avian Influenza Subtype H9N2 in African Houbara Bustards (Chlamydotis undulata undulata) and Gamebirds in Morocco: Clinico-Pathological Findings, Molecular Characterization, and Associated Coinfections

“…Furthermore, [11] reported a prevalence of only 1.86% (18/976 samples) amongst wild birds, mostly Charadriiformes. For Anserifomes, however, the PCR for H9N2 was negative for all the sampled specimens; similarly, [25] reported negative antibody titers against all the tested subtypes (H9, H7, and H5) in mallards in the UAE, which corroborates the results of El Mellouli et al (2022) [11]. Additionally, the environmental conditions of the regions, including high temperatures and ultraviolet indexes and low humidity, do not support AIV survival and persistence [25,55].…”

“…For Anserifomes, however, the PCR for H9N2 was negative for all the sampled specimens; similarly, [25] reported negative antibody titers against all the tested subtypes (H9, H7, and H5) in mallards in the UAE, which corroborates the results of El Mellouli et al (2022) [11]. Additionally, the environmental conditions of the regions, including high temperatures and ultraviolet indexes and low humidity, do not support AIV survival and persistence [25,55]. This means that the transmission of the virus to houbara bustards might have involved birds from other taxa [55].…”

“…Moreover, a recent serological survey of antibodies against H9, H7, and H5 avian influenza viruses in falcons and other wild bird species including houbara bustards and white-bellied bustards revealed a seroprevalence of 12.1% (16/132) and 15% (3/20) positives for antibodies against H9 in these birds, respectively. Conversely, other avian influenza subtypes were negative, which demonstrates the wide distribution and circulation of AIV H9 viruses among wild birds of the UAE, including bustards [25].…”

“…Our study represents the first report of a field outbreak in these species worldwide. Still, the evaluation of the susceptibility and pathogenesis of LPAI H9N2 in Moroccan Barbary partridges is advisable in order to understand the pathobiology of the virus in these species, since striking species-specific differences in susceptibility and in the pathogenicity of the virus were previously reported by Jöstl et al [25].…”