A MUTATION in H7N9 avian flu virus that can enhance the ability of the virus to infect humans was identified by researchers from the University of Hong Kong, which made the finding public yesterday.

    The research team from the university’s State Key Laboratory for Emerging Infectious Diseases of and the Department of Microbiology analyzed the H7N9 virus genome collected from 2013 onwards and revealed that efficient infection of both avian and human cells by H7N9 viruses is supported by a unique nucleotide substitution (NS-G540A) in NS segment, where the mutation is located within a previously undefined exonic splicing enhancer (ESE).

    Mutation in ESE identified in the viral genome of H7N9 virus enhances the ability of virus replication in mammalian cells. It is notable that human infections with H10N8 and H5N6 subtype avian influenza viruses contain the same mutation in the viral genome.

    This mutated nucleotide emerged in early 2000 in H9N2 strains and has since spread in avian influenza viruses, becoming the dominant genotype among avian influenza viruses from 2012 onwards, the researchers said. (Xinhua)