1st fatal case of bird flu in polar bear reported – 01/04/2024 – Environment

A highly lethal form of bird flu that has been spreading around the world has now been detected in a dead polar bear in Alaska. It is the first known case in Arctic animals, which are listed as endangered under the US Endangered Species Act.

The infected polar bear provides further evidence of how widespread this virus, a highly pathogenic form of H5N1, has become and how unprecedented its behavior has been. Since the virus emerged in 2020, it has spread to every continent except Australia. It also infected an unusually wide range of wild birds and mammals, including foxes, opossums, cougars and sea lions.

“The reported number of mammals with infections continues to grow,” said Bob Gerlach, Alaska’s state veterinarian responsible for local epidemiological control.

In most cases, the virus has not caused mass deaths in wild mammal populations (with the notable exception of South American sea lions). But it poses a new threat to the already vulnerable polar bear, which is threatened by climate change and the loss of sea ice.

“The concern is that we don’t know the general extent of what the virus can do to the polar bear species,” Gerlach said.

The polar bear was found dead last fall in far northern Alaska, near the town of Utqiagvik. Fluid samples collected from the animal initially tested negative for the virus.

However, according to Gerlach, when experts did a more comprehensive investigation, performing a necropsy and collecting tissue samples from the bear, they found clear signs of inflammation and disease.

Last month, tissue samples tested positive for the virus, according to the Alaska Department of Environmental Conservation. The virus was identified in several organs, Gerlach said. “I think it would be safe to say he died from the virus,” he said.

Alaska has already reported infections in a grizzly bear and a black bear, as well as several red foxes.

It is unclear how the polar bear contracted the virus, but there have been reports of sick birds in the area. According to Gerlach, the bear may have become infected after eating a dead or sick bird.

And scientists don’t know if this case is isolated or if there are other infected polar bears that have gone undetected. It can be difficult to monitor the virus in wild animal populations, especially those that live in places as remote as northern Alaska. “How do you know how many are affected?” Gerlach said. “We really don’t know.”

Local scientists, authorities and other experts will continue to look for signs of the virus in wild animals, including polar bears that appear dead or appear sick, Gerlach said.