Research progress in influenza A H9N2 avian virus related novel human infection:an overview

Since a novel avian influenza A(H7N9)virus emerged in China in 2013,China experienced seasonal epidemic waves of human infection and then subsequent human infections with H10N8 avian influenza virus were reported in some areas.Part of internal genes of H7N9 and H10N8 are derived from H9N2 virus and the two types of viruses present the difference in receptor binding property and the variation in key amino acid sites.The incidences of human infections with H9N2 and H10N8 virus were highly sporadic,with a significantly lower prevalence than that of H7N9 avian influenza virus.In addition,no familial cluster infection of the two viruses like that related to H7N9 infection were reported.The fundamental cause for the different epidemics related to the three viruses and whether a novel reassortment virus could result in new epidemics are still unclear.Therefore,we should carry out more researches on the novel avian influenza viruses and enhance etiology surveillance in order to cope with possible avian influenza pandemic.