The emergence of influenza A H7N9 in human beings 16 years after influenza A H5N1: a tale of two cities.

摘要: Summary Infection with either influenza A H5N1 virus in 1997 or avian H7N9 2013 caused severe pneumonia that did not respond to typical atypical antimicrobial treatment, and resulted high mortality. Both viruses are reassortants internal genes derived from H9N2 circulate Asian poultry. have genetic markers of mammalian adaptation their haemagglutinin polymerase PB2 subunits, which enhanced binding human-type receptors improved replication mammals, respectively. Hong Kong (affected by 1997) Shanghai 2013) two rapidly flourishing cosmopolitan megacities were increasing human population poultry consumption before the outbreaks. cities located along migratory route at Pearl River delta Yangtze delta. Whether widespread use vaccine east Asia—with suboptimum biosecurity measures live markets farms—predisposed emergence other subtypes needs further investigation. Why seems be more readily transmitted people than is still unclear.