Possible mechanism of H7N9 infectivity in humans
In March, 2013, a new H7N9 substrain of the bird flu virus was found. It is a typical low infectivity virus that is 38.6% fatal to humans.
A possibility is that the infective ability of the H7N9 virus in mammals, especially its infective ability in human cells, is determined by the PB2 polymerase gene, the M gene, surface influenza hemagglutinin (HA), the influenza virus nucleoprotein (NP), and neuramidinase (NA).
Within four days after a mammal is infected, adaptation to host occurs, and a mutagenic place change occurs, enabling the virus to rapidly realize cross species infection. The adaptation enhances the infective strength of the mutated virus in human cells, and this stregthened infectivity becomes fatal to humans. It may also be a molecular infectivity mechanism.