Region braces for return of avian flu

The start of spring means millions of migrating birds will soon flock to the Bering Strait region. While subsistence users and other residents welcome this return, they unfortunately need to be on the lookout for signs of sick and dead birds for the second year in a row.
A highly contagious strain of avian influenza is still running rampant among wild birds across the globe. The infection can make birds behave erratically—they might spin in circles on the water or lack their normal fear of humans before they drop dead.
The latest outbreak of this virus has affected about 150 bird species, and it has been detected in land and marine mammals, including seals, foxes and pet dogs.
“Many of us here in Alaska are anticipating an uptick in reports of highly pathogenic avian influenza-affected wildlife in the months ahead,” said Andy Ramey, director of the Molecular Ecology Lab at the Alaska Science Center in Anchorage, which is run by the U.S. Geological Survey.
Ramey gave a Strait Science talk last week to update residents on the recent detections of highly pathogenic avian influenza in wild birds and mammals. These outbreaks were once thought to be a problem only for domestic birds, but as Ramey explained, these viruses now seem to spread readily in the wild, too.
There’s a huge diversity of avian influenza viruses that wild birds carry. These viruses usually don’t cause sickness, but a small portion of those viruses can make domestic poultry sick when they spill over to birds like chickens and turkeys.
“The viruses that cause severe disease and death among chickens and turkeys are termed highly pathogenic avian influenza viruses,” Ramey said. “The tendency for viruses to cause serious disease and death among birds, or to become highly pathogenic, typically only occurs after these viruses have been introduced into poultry.”
These more severe viruses that evolve in poultry can spread rapidly and may result in the death and destruction of large numbers of domestic birds, he explained. For example, since the recent poultry outbreaks began last year, more than 58 million birds have died or have been culled in the United States.
While this was historically a problem exclusive to domestic birds, in the last two decades, more outbreaks have been detected among wild birds.
“Prior to 2002, there had been only one outbreak of highly pathogenic avian influenza and wild birds reported globally,” Ramey said. “Specifically, this was in terns in South Africa in 1961…Things have changed. Since 2002, outbreaks of highly pathogenic avian influenza and wild birds have become more common and more geographically widespread.”
Nearly all of these outbreaks in wild birds have been caused by the descendants of a virus that first emerged in domestic geese and Guangdong, China, in 1996, Ramey said.
“It is becoming increasingly clear that recent highly pathogenic avian influenza viruses have evolved such that they are now readily maintained and dispersed by wild birds,” he said. “These most recent highly pathogenic avian influenza viruses are sporadically spilling back from wild birds into domestic poultry. Viruses are also spilling over into domestic, captive and wild mammals. Outcomes for infected birds and mammals have been varied, though some level of mortality has been observed in virtually all species confirmed to be infected.”
Ramey said there were at least 229 confirmed detections of highly pathogenic avian influenza among wild birds in Alaska. The birds with the most infections include waterfowl, bald eagles, common ravens and gulls. In other parts of the world, seabirds have suffered major mortality events associated with highly pathogenic avian influenza.
“Terns, gulls, gannets and cormorants are among the seabirds most commonly reported to be affected,” Ramey said. “I therefore encourage residents of the Bering Strait region to please remain vigilant in watching for and reporting sick or abnormal numbers of dead or dying seabirds.”
So far, only a few cases of highly pathogenic avian influenza have been confirmed in wild mammals in Alaska—in a black bear, a brown bear and two foxes, including one that was killed in Unalakleet last year.
In other parts of North America, domestic mammals have also shown signs of infection. Earlier this month, the Canadian Food Inspection Agency issued a statement saying that avian flu was confirmed in a pet dog in Ontario. Before developing symptoms of the disease and dying, the dog had apparently chewed on a wild goose. Highly pathogenic avian influenza has also been detected in domestic cats.
Mammals that have died of these infections often displayed neurologic signs, such as seizures, circling, a lack of coordination, tremors and a lack of fear of humans. Necropsies often revealed that these animals had pneumonia, widespread damage to their organs and brain lesions. In these cases, it seemed that each animal independently contracted the infection from wild birds. Ramey said that so far there is no strong evidence of mammal-to-mammal transmission.
Worldwide, there have been 11 detections of highly pathogenic avian influenza in humans since January 2022, and the U.S. Centers for Disease Control & Prevention, or CDC, has maintained that the overall risk to human health remains low. Health officials have said they expect the risk to be especially low for those exposed to wild birds. However, it seems that a link between potential wild animal or environmental exposure and a recent human case in South America is now being investigated. The CDC announced this month that Chile is dealing with its first reported human infection of highly pathogenic avian influenza.
“The Chilean patient was a 53-year-old man with symptom onset on March 13,” the CDC said in a statement. “He was hospitalized with severe illness and remains in respiratory isolation under multidisciplinary management, with mechanical ventilation due to pneumonia. After hospital admission on March 22, the patient received antiviral treatment with oseltamivir and antibiotic treatment.”

Highly pathogenic avian influenza had been detected in wild birds and sea lions in the coastal region of northern Chile where the patient lived.
“Potential contact of the patient with wild birds, marine mammals and /or environmental exposures remains under investigation,” the CDC said. “Close contacts of the patient have been asymptomatic and have tested negative for influenza viruses, indicating that no known human-to-human transmission occurred.”
Because marine mammals like seals and sea lions have been affected by the virus in the North Atlantic and off the coast of South America, Ramey said residents of the Bering Strait region should be vigilant, too. He said they should look for sick or abnormal numbers of dead marine mammals, “especially if encountered in proximity to sick seabirds, or unusual numbers of birds found dead.”
Health officials 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.  
Ramey encouraged those who see sick or dead wild birds to call the U.S. Fish and Wildlife Service Alaska Sick and Dead Bird Hotline at 1-866-527-3358 or 907-229-6357. Sick and dead wild mammals, such as foxes, should be reported to the Alaska Department of Fish and Game: dfg.dwc.vet@alaska.gov.
Reports can also be posted to the Local Environmental Observer Network, www.leonetwork.org, or locally to Gay Sheffield, UAF Alaska Sea Grant at (907) 434-1149.