摘要Human outbreaks of highly pathogenic avian influenza (HPAI) such as H5N1 and novel avian strains such as H7N9 have provoked significant public health concern.An outbreak of H5N1 in humans was first reported in Hong Kong (HK),China in 1997.This event was curtailed by a variety of public health measures including the culling of over 1.5 million chickens in the city.1H5N1 has since re-emerged in multiple countries with over 600 reported infections and,since 2003,a case fatality of about 59％ (World Health Organization (WHO) report,as of January 24,2014).A clear picture of the prevalence and transmissibility of avian influenza strains in humans is lacking,in part due to sparse epidemiological data and limitations in current detection methods.A recent meta-analysis estimated a 1.2％ (95％ CI:0.6％-2.1％)seropositive rate for H5N1 in humans.2 Here we argue that H5N1 seroprevalence could be region specific,due to differing levels of exposure to wild and domestic fowl.