Pathogenic mechanism of H7N9 avian influenza virus: single nucleotide mutation of G540A.

Most avian influenza viruses are less capable of infecting humans, with the exception of H7N9.
A genetic mutation in the H7N9 virus has allowed it to infect both birds and mammals, including humans, a team of researchers at the University of Hong Kong in China reported in the British journal Nature Communications.
new findings will help to gain insight into the pathogenic mechanisms of the avian influenza virus.
H7N9 avian influenza virus is a subsype of influenza A virus that is usually transmitted only in poultry, but human infections have recently increased.
current transmission routes are mainly respiratory transmission or close contact with the secretions of infected birds, excreta, or through contact with virus-contaminated environmental infections.
are the natural hosts of many influenza viruses, but only a few of them can cause disease in humans.
the mechanism behind the spread of such viruses from birds to humans, the academic community has long had limited understanding.
, Chen Hongxuan, Yuan Guoyong and others at the University of Hong Kong analyzed the H7N9 virus in communication and found a single nucleotide mutation called G540A in their non-structural protein (NS) genome.
Viruses that generally infect humans are limited in spread in poultry, but the G540A mutation enhances the ability of the H7N9 virus to reproduce in mammalian (including human) cells, while also allowing the virus to spread effectively in birds.
researchers say this "adaptive reproductive preset mutation" gives the H7N9 virus a critical ability to infect humans across species not found in other avian influenza viruses.
new findings provide a molecular marker for monitoring cross-species infections of avian influenza viruses and help develop new anti-flu drugs.
has been concerned about the rising number of human cases of H7N9 avian influenza.
world health organization has previously said that recent observations suggest that the H7N9 virus is becoming "highly pathogenic" to birds, but there is no evidence that the virus has acquired the ability to spread from person to person.
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