An outbreak of avian cholera just downriver from the Tri-Cities has killed as many as 3,300 birds, most of them ducks, state and federal officials said Monday.
About 3,000 dead birds have been picked up at the McNary National Wildlife Refuge, nearby ponds east of Burbank and elsewhere near the refuge on private land and the Columbia River.
U.S. Fish and Wildlife Services continued collecting and incinerating carcasses on the McNary refuge this weekend, bringing the total there to 1,092 dead birds of the estimated 3,000 found in Washington state.
Most were ducks, but a few other birds, including a barn owl and great blue herons, also may have been killed by the avian cholera bacteria. Tests on the carcasses of emaciated raptors showed they did not have the bacteria.
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In addition, about 250 to 300 dead birds have been found in Oregon.
People are not at high risk of infection, but should avoid handling sick or dead birds.
When you pack so many waterfowl so close, it is going to make it tough when an avian cholera-infected bird shows up.
Mark Kirsch, John Day watershed acting manager
Many of the dead birds in Oregon were found along the Columbia River from the state border to Irrigon and also near Milton-Freewater, Ore., south of Walla Walla, in what is suspected to be a linked outbreak.
McNary refuge crews had been finding fewer dead birds each day, until the weather recently turned colder again and numbers jumped, said Dan Haas, visitor services manager for the Mid-Coumbia River National Wildlife Refuge.
Ducks are congregating where they find open water that has not frozen over.
“When you pack so many waterfowl so close, it is going to make it tough when an avian cholera-infected bird shows up,” said Mark Kirsch, John Day watershed acting manager for the Oregon Department of Fish and Wildlife.
As high temperatures warm into the 40s, the outbreak should dissipate, Haas said.
Washington State Fish and Wildlife Department staff have not seen a recurrence of the recent outbreak on private ponds east of Burbank, said Matt Wilson, waterfowl specialist for the department.
Avian cholera is caused by a bacteria that is highly contagious and spreads quickly through bird-to-bird contact, ingestion of food or water containing the bacteria, or scavenging of infected carcasses.
Infected birds may be lethargic, swim in circles of fly erratically. They die quickly after infection, sometimes in as little as six hours.