Researchers have warned that a mutation in a subtype of the avian flu virus could lead to an epidemic or pandemic.
The study was conducted by researchers at the University of Nottingham, in collaboration with the China Agricultural University in Beijing, the Chinese Academy of Sciences and the Chinese Center for Disease Control and Prevention.
They discovered that the H3N8 avian influenza virus (AIV), endemic in poultry farms in China, is mutating in a way which could increase the risk of the disease passing to humans.
The scientists used laboratory mice and ferrets as models for human infection, which identified several adaptive changes which caused severe animal infections and made it transmissible in the air through respiratory droplets.
This means that human populations could be vulnerable to infection by the newly mammalian adapted H3N8 AIV at an epidemic or pandemic proportion.
If contracted by humans, the H3N8 AIV has been found to cause acute respiratory distress syndrome and could be fatal.
The first case of H3N8 AIV infecting a human was identified in April 2022 when a five-year-old boy in China contracted the virus, suffering only mild symptoms.
Including this, the virus has now caused two confirmed human cases in 2022, followed by a fatal infection in 2023.
However the mutated virus has not yet overcome acid resistance to influenza virus which, if achieved, could give it transmissibility and adaptability in mammals and humans.
The researchers stress that further research should be conducted to closely monitor how such viruses in poultry and humans mutate.
Professor Kin-Chow Chang, of the University of Nottingham, said: “We demonstrate that an avian H3N8 virus isolated from a patient with severe pneumonia replicated efficiently in human bronchial and lung epithelial cells, was extremely harmful in its effects in laboratory mammalian hosts and could be passed on through respiratory droplets,”
He continued: “Human populations, even when vaccinated against human H3N2 virus, appear immunologically naive to emerging mammalian-adapted H3N8 AIVs and could be vulnerable to infection at epidemic or pandemic proportion.”
The full study can be found in the journal Cell.
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