Oregon becomes 22nd state with avian flu in dairy cattle as Washington cases grow

Federal lab testing found HPAI H5 clade 2.3.4.4b in the Oregon herd. APHIS said it will release genetic sequencing results once they are available.

APHIS said it is working with the Oregon Department of Agriculture on more on-farm investigations, diagnostic testing and epidemiological data collection. The agency said the detection does not change USDA's HPAI eradication strategy.

Washington confirmed its first infected dairy herds on October 8. Sequencing of those first herds found H5N1 genotype B3.13, the strain behind most US dairy herd cases. APHIS said the findings fit with spread from Idaho, likely through cattle movement.

State officials have since confirmed a Benton County herd that routine surveillance caught before any cows got sick. According to the Associated Press, Yakima County officials have reported 33 infected herds.

Three Washington residents have been infected after exposure at dairies with infected cattle. One of them, a Yakima County resident with underlying health conditions, was hospitalized and died November 1. It was the first US avian influenza death in a year. A CDC spokesperson told the AP that the agency found no changes in that patient's virus that would make it spread more easily or cause more severe disease.

Since early October, Oregon is the third state to report its first infected dairy herd, after Washington and Indiana. Indiana's case was confirmed November 2 through routine milk testing. The dairy cattle outbreak began in March 2024, and APHIS said it has seen cases in previously unaffected states this year.

APHIS said the FDA is confident that pasteurization inactivates the virus and that the commercial pasteurized milk supply is safe. The CDC considers the risk to the general public low. People exposed to infected birds or mammals through work or recreation are at higher risk.