Is the highly pathogenic avian influenza the new normal in wild birds?

The return of spring means migratory birds will soon flock to the Bering Strait region. And now for a few years in a row, that also comes with a potential threat: the spread of a contagious form of bird flu, known as highly pathogenic avian influenza, or HPAI.

As the outbreak continues, researchers and wildlife managers say it’s important for residents to continue reporting strange-behaving and sick-looking animals.

HPAI has been spreading in bird populations around the world since 2020. The virus spreads quickly among domestic birds and has led to the killing of millions of animals at industrial poultry farms. But this outbreak of HPAI is different from previous events in that it has proved deadly for wild birds, too. And it’s jumped to mammals like foxes, bears, seals and, in at least one case in Utqiagvik, a polar bear.

A few human infections have also been documented globally, though none have proved deadly. Just this week, the U.S. Centers for Disease Control confirmed that a person in Texas tested positive for HPAI after exposure to dairy cattle presumed to be infected.

“The patient reported eye redness (consistent with conjunctivitis), as their only symptom, and is recovering,” the CDC said in a statement on Monday. “The patient was told to isolate and is being treated with an antiviral drug for flu.”

This case did not change the health agency’s assessment that the virus poses a low risk to human health.

“However, people with close or prolonged, unprotected exposures to infected birds or other animals (including livestock), or to environments contaminated by infected birds or other animals, are at greater risk of infection,” the CDC said.

That risk assessment might not be so comforting to residents of the Bering Strait region who depend on subsistence harvests and regularly handle wild animals, as Alaska Sea Grant agent Gay Sheffield noted during a Strait Science lecture last week.

“We’re getting into things that are a little nerve-wracking if your livelihood is accessing clean, healthy populations of many, many different food sources in this region,” Sheffield said. “So, are we going to have to learn to live with this? And if that’s the case will there be some consistent monitoring and surveillance, so we know where we are with it?”

Andy Ramey and Christina Ahlstrom, who are both research scientists at the USGS Alaska Science Center in Anchorage, had been presenting the latest findings in the HPAI outbreak during the lecture.

Ramey said no one knows the ultimate outcome of this outbreak, but he wanted to provide some historical context from past outbreaks. Other forms of bird flu known as low pathogenic avian influenza are widely present in birds but cause few or no symptoms. With these low pathogenic viruses, there is sometimes a “selective sweep,” Ramey explained, where one virus outcompetes others, and the competitors disappear. If there eventually becomes a low pathogenic avian influenza that’s similar to but more transmissible than the current highly pathogenic avian influenza, then it might spread around the world and lead to antibodies that are similar enough to help promote immunity.

“There’s a roadmap that that could happen,” Ramey said.

But Ramey also offered a more pessimistic scenario: Between 1961 and 2002, there were just two detections of HPAI in wild birds. “Things have changed quite a bit,” he said. This new regime where infections are now common among wild birds might turn out to be more unpredictable.

Despite this novel situation, funding for monitoring avian influenza is much smaller than it was even as recently as 2009 when another outbreak of HPAI was documented in Alaska, Ramey said. And all samples from suspected HPAI cases from across the country have to go through one USDA lab in Iowa to be confirmed through testing, which causes delays in reporting.

Many of the samples from Alaska that have been tested at the USDA’s lab have also been genetically sequenced. Scientists hope that by studying the DNA of different HPAI strains, they can understand more about the future risks associated with the virus.

Christina Ahlstrom, the other scientist at the lecture, explained that researchers were able to look at the genetic sequence of the different HPAI strains found in infected animals from 16 different boroughs or census areas in Alaska in 2022. She and her colleagues examined 14 viruses from poultry, 159 viruses from 24 species of wild birds, and four viruses from mammals (one from a black bear, two from a brown bear and two from foxes).

They detected seven different variations of HPAI among those samples. The researchers found that the three most widespread genotypes were also the three estimated to be the first to be introduced into the state.

Ahlstrom said a logical explanation for this might be that wildlife at the beginning of the outbreak may be more susceptible to infection from a virus they haven’t been exposed to before, but as time goes on, they may develop antibodies that prevent them from getting sick.

Wildlife managers and researchers continue to urge residents to report cases of strange behavior and suspicious deaths in wild birds. Concerned observers can contact Sheffield or Kawerak’s Subsistence Director Chuck Menadelook. Strange behavior and deaths in animals could also be reported to the Alaska Department of Fish and Game.

Sheffield noted that efforts to monitor the health of other wild species have been undermined elsewhere. The U.S. Fish and Wildlife Service announced recently that it was discontinuing a program in which it hired local people to collect tissue to look at the health of walruses. Her take on the overall monitoring situation: “We are on our own, we are responsible for what we see around us, we always seem to have to volunteer and we’re going to have to continue to do that.”

Ramey said that a high volume of reports of suspected HPAI cases, even if samples aren’t collected and tested, might help managers and re“We are on our own, we are responsible for what we see around us, we always seem to have to volunteer and we’re going to have to continue to do that.”

searchers at various agencies make the case for more funding and monitoring.

“I just want to stress that your reports are important,” Ramey said.

Health officials’ recommendations for minimizing risk of human infection also remain the same.They have urged anyone hunting birds or collecting eggs for subsistence to wear protective gear like gloves and, if available, eye and respiratory protection like goggles and face masks. People are also advised to keep hunting and processing equipment clean, to avoid harvesting animals that appear sick and to thoroughly cook meat and eggs to an internal temperature of 165°F. People should not smoke, eat or drink while handling harvested birds. Dogs should also be prevented from eating sick or dead birds.

“We are on our own, we are responsible for what we see around us,

we always seem to have to volunteer

and we’re going to have to continue that.” to do

- Gay Sheffield