Bird Flu Found in Mammals But Risk to Humans Low, Experts Say

AFP-Jiji

13:20 JST, March 2, 2023

PARIS (AFP-Jiji) — Experts have warned that the recent detection of bird flu in mammals including foxes, otters, minks, seals and even grizzly bears is concerning but emphasized that the virus would have to significantly mutate to spread between humans.

Since late 2021, Europe has been gripped by its worst-ever outbreak of bird flu, with North and South America also experiencing severe outbreaks.

This has led to the culling of tens of millions of domestic poultry worldwide, many with the H5N1 strain. The global outbreak is also responsible for the deaths of tens of thousands of wild birds.

Tom Peacock, a virologist at the Imperial College London, told AFP that it constitutes a “panzootic” — a pandemic among animals, in this case birds.

“We are not fully sure why it’s happening now but we think this might be driven by a slightly different strain of H5N1 which is spreading very effectively in wild, migratory birds,” Peacock said.

It is rare that bird flu jumps over into mammals — and rarer still that humans catch the potentially deadly virus.

Last month, the U.K. Health Security Agency said that a fox had recently tested positive for H5N1.

It joins eight foxes and otters that tested positive in the U.K. last year, all of which had a PB2 mutation.

Peacock said that this mutation “allows the virus to replicate better in mammalian cells.”

But further mutations would be “required for the virus to cause a flu pandemic” in humans, he added.

France announced in January that a cat had been put down after testing positive for H5N1, and the U.S. state of Montana’s parks service said three grizzly bears with bird flu had been euthanized.

All of these mammals were suspected to have eaten infected birds.

Paul Wigley, a professor of animal microbial ecosystems at the U.K.’s Bristol University, said that while “there is no transmission within mammalian populations, the risk to humans remains low.”