Outbreak of H5N1 avian influenza on dairy farms in Washington state

According to the United States Department of Agriculture as of October 30, 2026, the H5N1 avian influenza virus has been confirmed in 40 dairy herds in Washington State. The majority of outbreaks (39) were recorded in Yakima County, with one more in neighboring Benton County. Against this backdrop, the total number of affected states nationwide increased to 21 after the virus was detected for the first time in Newton County, Indiana.

Three confirmed human cases of infection among individuals who had contact with infected cows have been registered in Yakima County. One of the patients, who had underlying health issues, died after hospitalization. The third patient is experiencing the disease without severe symptoms and hospitalization. At the same time, medical organizations, including the Yakima County Health District, the Washington State Department of Health, and the CDC, have not released overall statistics on testing dairy farm workers for the virus.

According to health authorities' recommendations, farm workers and individuals with close contact with livestock animals are at the highest risk. Workers are advised to use protective gear, including respirators, safety goggles, gloves, and rubber boots, and to consult doctors or the Yakima County Health District if symptoms appear.

Experts note that pasteurized milk remains safe for consumption, but the public should completely avoid raw milk and unpasteurized dairy products, and refrain from giving them to domestic pets. The risk of human-to-human transmission is assessed as extremely low and has never been documented before in the US. Genetic analysis of the biomaterial did not reveal any changes that would facilitate easier spread of the virus or make the disease more severe.