The number of workers at a Franklin County commercial egg farm who have now tested positive for avian influenza has increased to eight, according to preliminary test results.

The outbreak at the large farm has the first human cases of highly pathogenic avian influenza, or H5N1, known in the state of Washington.

Of the eight preliminary positive cases, two were confirmed positive Thursday night with additional testing by the Centers of Disease Control and Prevention. Confirmation testing of the other six cases in pending.

The Washington state Department of Agriculture says two more cases in birds of the highly pathogenic form of avian influenza have been reported in two more counties since the Pasco area outbreak was confirmed Oct. 15.

A backyard flock was confirmed to be infected in Kitsap County Oct. 18, and preliminary positive results for a backyard flock in Lewis County were reported Wednesday Oct. 23.

The three detections in Washington state this month are believed to have been caused by migrating waterfowl spreading the virus to domestic chickens and, in the case of backyard flocks, other domestic birds. They are the first three reports in 2024 in the state.

Oregon also is impacted.

It reported Thursday that a commercial poultry operation in Clackamas County had H5N1 detected and that 150,000 birds were being euthanized.

At the egg farm near Pasco, about 800,000 birds were euthanized and eggs were destroyed.

The United States Department of Agriculture says since 2022, when the outbreak started in the United State, 104 million birds have been affected in 48 states.

Clinic set up at farm

No infected birds or eggs have entered the food supply and the immediate risk to the general public of the current strain of the virus remains low, according to the Department of Agriculture.

The workers in Franklin County known or suspected to have avian influenza were infected by their work in heavily contaminated environments as they cared for the chickens and then euthanized them at a large egg-producing farm near Pasco.

None of the workers infected at the egg farm near Pasco has been hospitalized.

Benton Franklin Health District has set up a makeshift clinic at the Franklin County farm and has taken nasal or eye swabs to test 69 workers, said Carla Prock, senior manager of community health in the district.

The number of presumed positive test results has doubled from four as of Sunday, Oct. 20, to the eight suspected cases Thursday.

The health district also is offering workers Tamiflu and seasonal flu shots at its temporary farm clinic

Tamiflu is a prescription antiviral medicine commonly used for seasonal influenza that is being offered as a preventative measure for avian influenza, said Dr. Steven Krager, the interim health officer for Benton and Franklin counties. It also is being offered to workers who have symptoms or have tested positive to help them fight the infection.

The seasonal flu shot that workers are being offered will not protect them against avian influenza. But it could help workers from getting both types of flu at once.

There are no known cases in the United States of human-to-human transmission of the disease.

Avian and seasonal influenza

However, infection with both avian influenza and seasonal influenza at the same time increases the risk that viruses can share information and a strain of avian influenza virus could arise that spreads easily from person to person as the seasonal influenza does, according to the Washington state Department of Health and Krager.

The current strain of avian influenza does not easily infect people, Krager said.

Both local and temporary workers who have been staying at hotels have had preliminary positive test results.

The temporary workers may have been helping with the difficult job of euthanization and composting of chickens and eggs.

The Benton Franklin Health District has been offering guidance on isolation, both for workers living with their families, and those staying in hotels, Prock said. That includes recommending that a worker with preliminary positive results and a worker without symptoms not share the same hotel room.

Dr. Umair Shah, the Washington secretary of health, was in the Tri-Cities on Thursday to learn more about the response to the Franklin County incident and offer his support to Benton Franklin Health District staff.

Three employees of the CDC also are in the Tri-Cities to provide help, Prock said.

"We're watching this very closely," Krager said. "We're very concerned about worker safety and keeping workers as safe as possible."

Public health workers also are looking at possible ways to prevent another outbreak, he said.

No bird flu in WA dairies found

Although the large operation with the bird flu outbreak in Franklin County has not been identified by state or Tri-Cities officials, it follows a similar event in December 2022 at the large Oakdell Farms poultry operation north of Pasco.

And a Washington state surveillance zone established in the outbreak area near Pasco this month includes an Oakdell Farms egg operation.

Oakdell Farms also has farms in Utah and Idaho and sells eggs in 11 Western U.S. states under the Oakdell Egg Farms and store brands.

Active surveillance within about six miles of the commercial egg farm will continue until roughly 14 to 16 days after compost piles for potentially infected birds and their eggs are capped, according to the Washington state Department of Agriculture.

There have been no confirmed or suspected cases on dairy farms in Washington state, according to the state Department of Agriculture.

The CDC announced the first detected outbreak of H5N1 in several dairy herds in March and has now found infections in 338 dairy herds in 14 states.

Employees or contractors who may have worked on a poultry farm in Benton or Franklin counties since Oct. 7 should contact the local health department at 509-460-4550 if they have symptoms such as red eyes, feeling feverish, cough, sore throat or other flu-like symptoms, says the Washington state Department of Health.

People with backyard poultry should report any sick or dead birds to the Washington state Department of Agriculture at 1-800-606-3056 or report sick domestic birds online. Veterinarians should report sick or dead domestic animals or livestock suspected of having avian influenza to the Department of Agriculture at fortress.wa.gov/agr/apps/rad/.

Contact with sick or dead wildlife should be avoided by both people and their pets. Sick or dead wildlife should be reported to the Washington state Department of Fish & Wildlife.

For more information on safety precautions, go to WA-DOH.wa.gov/avian-influenza. 

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