The first cases of H5N1 avian influenza have been detected in cows in Washington.

The first cases of H5N1 avian influenza in dairy cows have been confirmed in Washington State. The virus was detected in Yakima County on two dairy farms, which are currently under quarantine following confirmation of the diagnosis by federal laboratories. Prior to this, no positive results had been recorded: over the past two years, more than 7,000 tests were conducted as part of monitoring, and all of them returned negative results. The national disease outbreak among dairy livestock began in March 2024, affecting farms across 19 states.

Strict biosecurity measures have been implemented on the affected farms, specialists are conducting investigations and additional inspections, and veterinarians are treating sick livestock animals. According to the department, most affected cows recover with supportive care in about six weeks. The routes of virus spread between herds include infected livestock animals, contaminated milk, as well as the movement of equipment, vehicles, and people, whereas wild birds are not considered the primary source of transmission.

For the general public and households, the immediate risk is assessed as low. Officials state that pasteurized milk and dairy products are safe, and a shortage is not expected, as pasteurization inactivates the virus. At the same time, raw milk and raw dairy products are recognized as unsafe, since infected cows can shed the virus through them; the agencies do not recommend giving them to people and livestock animals. The highest risk is faced by farmers, veterinarians, and facility workers who come into contact with sick livestock animals or raw milk, and they are instructed to use protective equipment and monitor for symptoms. No human infection cases associated with the Yakima County farms have been registered at this time.