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. 2015 May 1;211(9):1399-407.
doi: 10.1093/infdis/jiu529. Epub 2014 Oct 29.

Avian influenza A(H5N1) and A(H9N2) seroprevalence and risk factors for infection among Egyptians: a prospective, controlled seroepidemiological study

Mokhtar R Gomaa  1 , Ahmed S Kayed  1 , Mona A Elabd  2 , Dina Abu Zeid  2 , Shaimaa A Zaki  2 , Amira S El Rifay  2 , Lobna S Sherif  2 , Pamela P McKenzie  3 , Robert G Webster  3 , Richard J Webby  3 , Mohamed A Ali  1 , Ghazi Kayali  3
Affiliations

Avian influenza A(H5N1) and A(H9N2) seroprevalence and risk factors for infection among Egyptians: a prospective, controlled seroepidemiological study

Mokhtar R Gomaa et al. J Infect Dis. .

Abstract

Background: A(H5N1) and A(H9N2) avian influenza viruses are enzootic in Egyptian poultry, and most A(H5N1) human cases since 2009 have occurred in Egypt. Our understanding of the epidemiology of avian viruses in humans remains limited. Questions about the frequency of infection, the proportion of infections that are mild or subclinical, and the case-fatality rate remain largely unanswered.

Methods: We conducted a 3-year, prospective, controlled, seroepidemiological study that enrolled 750 poultry-exposed and 250 unexposed individuals in Egypt.

Results: At baseline, the seroprevalence of anti-A(H5N1) antibodies (titer, ≥80) among exposed individuals was 2% significantly higher than that among the controls (0%). Having chronic lung disease was a significant risk factor for infection. Antibodies against A(H9N2) were not detected at baseline when A(H9N2) was not circulating in poultry. At follow-up, A(H9N2) was detected in poultry, and consequently, the seroprevalence among exposed humans was between 5.6% and 7.5%. Vaccination of poultry, older age, and exposure to ducks were risk factors for A(H9N2) infection.

Conclusions: Results of this study indicate that the number of humans infected with avian influenza viruses is much larger than the number of reported confirmed cases. In an area where these viruses are enzootic in the poultry, human exposure to and infection with avian influenza becomes more common.

Keywords: avian; cohort; epidemiology; influenza; seroprevalence.

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Figures

Figure 1.
Figure 1.
Titer categories at study time points among subjects with or without exposure to poultry.
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References

    1. Saad MD, Ahmed LS, Gamal-Eldein MA, et al. Possible avian influenza (H5N1) from migratory bird, Egypt. Emerg Infect Dis 2007; 13:1120–1. - PMC - PubMed
    1. Meleigy M. Egypt battles with avian influenza. Lancet 2007; 370:553–4. - PubMed
    1. Kayali G, El-Shesheny R, Kutkat MA, et al. Continuing threat of influenza (H5N1) virus circulation in Egypt. Emerg Infect Dis 2011; 17:2306–8. - PMC - PubMed
    1. El-Shesheny R, Kandeil A, Bagato O, et al. Molecular characterization of avian influenza H5N1 virus in Egypt and the emergence of a novel endemic sub-clade. J Gen Virol 2014; 95:1444–63. - PMC - PubMed
    1. El-Shesheny R, Kayali G, Kandeil A, et al. Antigenic diversity and cross-reactivity of avian influenza H5N1 viruses in Egypt between 2006 and 2011. J Gen Virol 2012; 93:2564–74. - PubMed

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