Post Reply - A new pandemic

20 November 2024​
By Heidi Ledford​

doi: https://doi.org/10.1038/d41586-024-03805-4​

In a children’s hospital in Vancouver, Canada, a teenager is in critical condition after being infected with an avian influenza virus that has researchers on high alert.

Viral genome sequences released last week suggest that the teenager is infected with an H5N1 avian influenza virus bearing mutations that might improve its ability to infect the human airway. If true, it could mean that the virus can rapidly evolve to make the jump from birds to humans.

It’s a worrying development but it doesn’t mean that a new pandemic is imminent, says immunologist Scott Hensley at the University of Pennsylvania in Philadelphia. At present, there is no sign that the virus — which is related but not identical to the H5N1 virus infecting US dairy cattle— has been transmitted from the sick adolescent to other people.

“There is reason to be concerned,” he says. “But not reason to totally freak out.”

How did the teenager get infected?

That is unclear. The adolescent did not work or live on a poultry farm, and researchers have found no signs of H5N1 infection in household pets, said Bonnie Henry, a public health officer for the province of British Columbia in Victoria, Canada, during a press conference. “There is a very real possibility that we may not ever determine the source,” Henry said.

Why is this virus so concerning?

The sequencing data suggest that the teenager is infected with a mixture of viruses, all of which are similar to a lineage of H5N1 viruses that is currently infecting poultry and waterfowl in the region. But researchers have homed in on three key differences between those viruses and the teenager’s: two possible mutations that could enhance the virus’s ability to infect human cells, and another that could allow it to replicate more easily in human cells, not just in the cells of its usual avian host.

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