Bird Flu Outbreak Hits Oregon; Wildlife officials say ‘it’s definitely serious’
An outbreak of highly pathogenic avian influenza in wild birds and backyard flocks has killed thousands of birds across the state, Oregon Wildlife and Agriculture officials say.
The disease, typically known as bird flu, has been detected in nearly every county in Oregon. Its current strain is particularly deadly to wild birds, which are dying in greater numbers than during previous outbreaks.
The number of backyard flocks – which include chickens, ducks and other domesticated birds – also affected was much higher than in recent outbreaks. Although turkeys are particularly susceptible to the disease, only a few have died locally because Oregon is not a turkey-producing state, officials said.
Sick birds act as if they are drunk. They are uncoordinated and lethargic; they shake, swim in circles and fly to the sides of houses. Those who show symptoms usually die within 72 hours.
“It’s definitely serious,” said Ryan Scholz, state veterinarian with the Oregon Department of Agriculture.
Avian influenza viruses occur naturally in the environment, and avian influenza does not always cause mortality or even illness in birds. Some birds, such as mallards, have developed immunity to the disease, even to its highly pathogenic strains. They have no symptoms, but transmit the disease, most often through feces.
The virus usually arrives in the US from Europe or Eurasia, carried by waterfowl that fly thousands of miles. Birds spread the disease every time they land to rest.
Deadlier strains of bird flu have been on the rise in recent years. Highly pathogenic avian influenza has devastated wild birds and the poultry industry worldwide. The virus is now endemic in Europe and Asia.
This year may be even more deadly than usual. The virus usually disappears with dry and hot weather, as low-pathogenic strains of the disease naturally outcompete it. This happened in 2014-15, the last major domestic bird outbreak in the US.
But birds haven’t stopped getting sick this summer in the Pacific Northwest. They continued to die during the warmest months and well into the fall — an anomaly in how the virus usually works.
In recent weeks, wild birds have been sickened and dying from Fernhill Wetlands in Forest Grove to the Tualatin River Wildlife Refuge to the Willamette Valley Wildlife Refuge. It’s impossible to know exactly how many wild birds are affected, said Colin Gillin, state wildlife veterinarian.
“To say it was in the thousands would be an understatement,” Gillin said.
About 17 percent of the waterfowl tested tested positive for the disease, a “significant number,” Gillin said. Currently, the most affected species are cackling geese, but the disease also kills numerous bald eagles, hawks, owls and herons.
Songbirds and wild turkeys aren’t affected, Gillin said, because they don’t typically interact with waterfowl and aren’t a scavenger species.
There is also concern about snow geese afterwards nearly 400 sick or dead geese were found on Lake Wiser in western Washington state a few days ago and several tested positive for bird flu. Many of the dead birds were snow geese. Those birds are just starting to arrive in Oregon, so many more could die in the coming weeks in our state, Gillin said.
In other states, avian influenza has also been detected in mammals such as ferrets, foxes and coyotes – usually in younger animals.
The disease does not pose a great risk to humans, although some are infected with avian influenza viruses. Still, it’s a mutating disease, officials said, so hunters should wear protective gear like masks and gloves to safely handle wild birds, and should change clothes when they get home. Hunters should not kill birds that appear sick. They should also minimize dog interactions with waterfowl.
Some hunters worry whether the extinction will affect the duck and goose hunting seasons, which are now open.
“I see a lot of dead geese on Sauvie Island and a lot of sick ones,” local hunter Eric Strand said via email.
But Brandon Reishus, Oregon’s migratory bird coordinator, said it’s too early to predict. “We have no plans to close the hunt. But it is an evolving situation.”
The Oregon Department of Agriculture said 16 cases have been confirmed this year in smaller domestic bird flocks. That’s a significant increase from the two confirmed cases in the 2014-2015 outbreak, said Scholz, the Department of Agriculture veterinarian. More flocks are being tested following an increase in flock numbers in the past week.
About two thousand domestic birds have been euthanized or died from bird flu in Oregon this year in reported cases, Scholz said. Some backyard flock owners use only the birds or their eggs for home consumption, while others have hundreds of birds and sell their products to the public. The state imposed several bird flu in quarantine this summer and fall to prevent the sale of meat or eggs from areas affected by the virus.
There are no reported cases in commercial farms – farms with much larger herds that are often raised in large barns — probably because they have strict biosecurity measures, Scholz said.
Sick flocks ranged in size from 4 to 500. The larger the flocks, the more birds die quickly – so the disease risk for larger farms is significant. In the case of one large backyard farm with about 400 chickens, Scholz said, the birds started dying on Saturday, and by Monday there were “barrels of dead birds.” Agricultural officials had to euthanize the others.
And it’s not just a chicken problem. In addition to hundreds of dead chickens, this year’s epidemic has taken home ducks, quails, pheasants, and even a few emus.
With cooler weather and wild bird migration peaking in the coming weeks, the environment is ripe for transmission, Scholz said.
“Weather like this … it’s an opportunity for a perfect storm,” he said.
Wildlife officials say it’s OK to bag up and dispose of one to two dead wild birds in the trash. People can also shallow bury birds or simply leave them where they are in the wild. Officials said people should be careful handling the birds and should never transport them.
As for domestic birds, responsible owners can help prevent exposure of their flocks to wild waterfowl by fencing off access to ponds or grass fields, Scholz said.
Domestic flock owners should call the Department of Agriculture if more than one bird in their flock dies quickly, officials said. Reported cases are examined by a veterinarian and samples are collected for testing. If the disease is confirmed, all the birds are euthanized, Scholz said.
“Bird flu is 100 percent fatal” for domestic birds, which haven’t developed the immunity that some wild birds have, he added. “All the birds will die of disease. We would rather humanely euthanize them than wait for them to get sick and die.”
– Gosia Wozniacki; [email protected]; @gosiawozniacka
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