Zoonotic Influenza Viruses from China: An Increasing Pandemic Threat?
Yi Guan School of Public Health, The University of Hong Kong
The 2009 H1N1 influenza pandemic emphasised the threats continually emerging from the animal kingdom. Every year in China, different zoonotic influenza viruses are deemed to have “pandemic potential” despite uncertainties over their real and relative levels of threat. Three subtypes of influenza viruses have circulated at high prevalence in poultry in China for many years, persistently causing human infections. Phenotypically similar, yet genetically diverse; their surface genes form antigenically distinct sub-lineages, and incorporation of internal gene segments of varied origins has led to many genotypes but, as yet, no widespread human to human transmission. In China all known swine influenza virus types are hosted and frequent reassortment and sporadic human infections occur. Thus, China has all the attributes to generate a 2009 pandemic-like virus, but, to date, has not. We examine avian and swine influenza viruses uncovered by surveillance in China to more accurately assess their pandemic threat.