Epidemic of human-infected H7N9 avian influenza:advances in its biological research

In 2013, the Chinese CDC reported that the H7N9 avian influenza virus firstly infected human beings by poultry, and human infection with H7N9 avian influenza continued to be seasonally prevalent among the population.The H7N9 avian influenza virus had an amino acid mutation (Q226L, G186V) associated with the cross-species barriers on the HA protein, and possessed mammalian adaptive mutations, and the E627K, D701N mutation on the polymerase PB2 enhanced viral polymerase activity and virulence in mammals.As of September 2018, a total of 1 567 cases were reported and 615 died.In February 2017, H7N9 detected in patients in Guangdong Province showed high pathogenicity and lethality, and had a limited human-to-human transmission ability, posing a huge potential threat to humans.Sequence analysis revealed that several consecutive base fragments (KRTA) were added at the cleavage site of the amino acid sequence of HA protein.This paper reviews the current research on the epidemiological characteristics, genetic characteristics, prevention and therapy status of H7N9 avian influenza virus, in order to provide evidence for the prevention and control of H7N9 avian influenza.