H9N2 Chicken Flu Virus May Pose Human Pandemic Threat, Specialists Warn

This Neglected Chicken Flu Pressure Would possibly Be the Subsequent Pandemic Threat

By Rachel Fieldhouse & Nature journal

A hen flu virus that has usually been ignored as a result of it largely causes minor illness in birds has the potential to trigger a human pandemic, says a staff that has tracked how the H9N2 virus has develop into higher tailored to contaminate folks. The researchers say extra surveillance of the virus is required.

Up to now few years, surveillance has been centered on the avian influenza virus H5N1, which has unfold throughout most continents and might trigger extreme illness and demise in folks. Since 2020, H5N1 has killed about 21 folks. In North America, the virus can also be spreading amongst dairy cows.

Much less consideration is being paid to H9N2, says Kelvin To, a medical microbiologist on the College of Hong Kong, regardless of the virus being the second most typical pressure of hen flu that infects folks. H9N2 has triggered 173 infections in folks since 1998, largely in China, says To, who introduced his staff’s analysis on the Pandemic Analysis Alliance Worldwide Symposium in Melbourne, Australia, on 27 October.

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H9N2 could be extra prevalent than we notice, says Michelle Wille, who research hen flu on the Peter Doherty Institute for An infection and Immunity in Melbourne. Infections are most likely being missed as a result of they don’t lead to extreme an infection or hospitalization in folks, or as a result of persons are extra generally examined for the H5N1 as an alternative, she provides.

Genetic modifications

Scientists are but to seek out proof of person-to-person transmission of H9N2, which might be wanted for it to result in a pandemic. However To and his staff have discovered that H9N2 underwent genetic modifications that started round 2015 which have made the virus extra infectious. In cell-based experiments, a model of the H9N2 virus collected in 2024 contaminated extra human cells than did a historic pattern collected in 1999. The fashionable model additionally confirmed improved binding to varied receptors on human cells. This implies the virus has tailored to unfold amongst folks, reported To and his colleagues in Rising Microbes & Infections earlier this month.

The virus must bear a number of extra modifications earlier than it may trigger sustained transmission between folks, says Wille. The virus has to alter to preferentially bind to human receptors as an alternative of receptors present in hen cells and has to adapt how effectively it grows at temperatures and pH ranges of people, that are totally different from birds.

Elevated surveillance and communication in regards to the dangers of avian influenza is required, says Wille. A part of the difficulty is that international locations will not be required to report infections brought on by strains which are thought of to be of low pathogenicity, corresponding to H9N2.

To says larger virus surveillance amongst mammals in shut contact with wild birds or poultry would assist scientists perceive whether or not the virus has been tailored to mammals aside from people.

He’s involved that when animals are contaminated with a number of viruses, genetic materials will get blended and matched when the viruses replicate contained in the cell and will create new viruses that may infect people. Scientists are involved that this reassortment may additionally occur in folks, too. To says different analysis has discovered genetic materials from H9N2 among the many viruses which have triggered earlier hen flu outbreaks in folks.

This text is reproduced with permission and was first revealed on October 27, 2025.

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