Researchers have documented a hundred more cases of wild birds in Alaska infected with highly pathogenic avian influenza [HPAI], commonly known as bird flu, since last year. Yet there is evidence that a variety of species in the state are building up immunity to the fatal disease.
Andy Ramey, a Research Wildlife Geneticist at the Alaska Science Center under the U.S. Geological Survey (USGS), gave an update about the bird flu across the state during the annual fall meeting of the Alaska Migratory Bird Co-Management Council held in Kodiak on Sept. 11 & 12.
Although the number of documented cases in Alaska pales in comparison to other parts of the world, the virus is still persisting in the state.
“Here in Alaska mortality among wild birds and mammals has so far been reportedly to be far more sporadic and of lower magnitude," Ramey explained. "So for an example, HPAI has been confirmed among a total of only 329 wild birds in Alaska as of Wednesday, Sept. 11.”
Ramey said more than half of those cases were found in ducks that appeared to be healthy when harvested or sampled by hunters. The Alaska Science Center has been conducting an annual sampling effort since 2011 in partnership with the community of Cold Bay and local subsistence hunters in the Izembek National Wildlife Refuge area, just north of the city. Ramey said that area is an important crossroads where avian diseases are commonly introduced from East Asia into North America.
The bird flu has spread to other mammals like red foxes and brown bears over the last couple years. This includes a polar bear on the North Slope that died in October of 2023 from the virus, and an infected Kodiak brown bear cub in 2022.
So far in Alaska, the virus has not been documented in marine mammals, but it has been linked to a die-off of various species of seals in Maine. Ramey said it is still possible this could happen in the state and encourages communities and subsistence hunters to report any potential cases they find going forward.
Most recently, the disease turned up at the beginning of this month on Sept. 4 in a bald eagle in the Aleutians. Ramey said eagles are one of the most common species to experience death or become sick from the bird flu in Alaska.
“Bald eagles and common ravens have been the most commonly reported species affected. Other wild bird species reported to be adversely affected by HPAI in Alaska include Black Brant, cackling and Canada geese, common murres, various gulls, and short tailed shearwaters," Ramey stated.
Despite more cases of avian influenza documented in Alaska this year, Ramey said there is evidence to suggest that at least some wild ducks in the Aleutians and possibly other widespread species in Alaska, are starting to build up immunity to the virus by developing antibodies after surviving the bird flu.
“So there are several independent lines of evidence that suggest widespread exposure of Alaska wildlife to HPAI viruses, since late 2021, which may have led to significant numbers of animals with antibodies to these viruses.”
For example, roughly 30% of cackling geese sampled in 2022 had antibodies to HPAI, but that increased to 50% in 2023.
The evidence suggests the same is happening for other species of mammals that have been exposed to the virus too, such as red foxes or brown bears.
For humans so far 15 cases in the U.S. have been reported by the Center for Diseases Control or CDC since 2022. None of those came from exposure to infected wild birds, but the majority involved the poultry industry.
Going into the fall subsistence hunting season for migratory birds, Ramey encourages hunters to remain vigilant and safely cook and prepare the meat before eating it, which includes cooking it to an internal temperature of 165 degrees Fahrenheit. When handling and cleaning game, hunters should wear gloves, wash hands, and disinfect knives and equipment used for cleaning.
If you see an animal or bird that appears to have the bird flu, demonstrates strange behavior, or seems sick, then you can report that information to the U.S. Fish and Wildlife Service (USFWS) by calling 1-866-527-3358. or 907-229-6357 which is the sick and dead bird hotline. Take photos and videos to help officials better document any report of HPAI.
