Understanding the profile of human cases of different AIV subtypes would guide control strategy. Continued monitoring of human infections with AIVs is essential for pandemic preparedness.
We described the characteristics of more than 2,500 laboratory-confirmed human infections with AIVs. Human infections with H5N1 and H7N9 were more frequently reported than other subtypes. The risk of death was highest among reported cases infected with H5N1, H5N6, H7N9 and H10N8 infections. Older people and males tended to have a lower risk of infection with most AIV subtypes, except for H7N9. Visiting live poultry markets were mostly reported by H7N9, H5N6 and H10N8 cases, while exposure to sick or dead bird mostly reported by H5N1, H7N2, H7N3, H7N4, H7N7 and H10N7 cases.
We reviewed the epidemiology of human infections with AIV from the literature including reports from the World Health Organization, extracting information on virus subtype, time, location, age, sex, outcome and exposure.
Avian influenza A viruses (AIVs) are among the most concerning emerging and re-emerging pathogens because of the potential risk in causing an influenza pandemic with catastrophic impact. The recent increase in domestic animals and poultry worldwide was followed by an increase of human AIV outbreaks reported.