Experts warn of rapidly changing bird flu viruses in record outbreak

PARIS – The virus causing record cases of bird flu around the world is mutating rapidly, experts warn as countries call for vaccination of poultry.

While emphasizing that Although the risk to humans remains low, Experts who spoke to AFP said the rapid increase in the number of mammals infected with bird flu was a cause for concern.

Since its first appearance in 1996, the H5N1 avian influenza virus has been largely restricted to seasonal outbreaks.

But in mid-2021 “something happened” and a group of viruses was created. much more contagious, According to Dr. Richard Webby, director of the World Health Organization’s Collaborating Center for Animal Influenza.

Since then, the epidemic has continued throughout the year, spreading to new areas and leading to mass bird mortality and the culling of tens of millions of poultry.

Dr. Webby, a researcher at St. Jude Children’s Research Hospital in Memphis, USA, told AFP it was “by far” the largest bird flu outbreak the world has ever seen.

He led a study published this week in Nature Communications that showed the virus evolved rapidly as it spread from Europe to North America.

The study said viruses arriving in North America were becoming more virulent, meaning they caused more dangerous illnesses.

When researchers infected ferrets with one of the new strains of bird flu, they found an unexpectedly “large amount” of the virus in their brains, which caused more severe illness than previous strains. said Dr. Webby.

“This virus is not static, it is changing,” he said, stressing that the risk to humans remains low.

This makes it more likely that “even if by accident,” the virus “acquires genetic features that make it more like a human virus,” he said.

Rarely, humans can become infected with this sometimes fatal virus, usually after close contact with infected birds.

The virus has also been detected in a surging number of mammals, which Dr. Webby described as “a really, really troubling sign.”

Chile announced last week that around 9,000 sea lions, penguins, otters, porpoises and dolphins have died from bird flu along its northern coast since the beginning of the year.

Most mammals are thought to have contracted the virus by eating infected birds.