Bird flu reaches Oregon dairy cows as union warns worker cases go uncounted

H5N1 bird flu has been confirmed in an Oregon dairy herd for the first time, the U.S. Department of Agriculture's Animal and Plant Health Inspection Service announced this week. The finding pushes the dairy outbreak into one more Western state just as neighboring Washington deals with a surge in infected herds and a farmworkers' union warns that human infections there are going uncounted.

Since the virus was first found in U.S. dairy cattle in 2024, it has turned up in 22 states. The latest numbers show the outbreak is active, not winding down. In the last 30 days, 51 cattle herds have been infected. In the past week alone, the virus was detected in two Idaho herds as well as the Oregon herd. Washington has recorded 43 herd detections since Oct. 8, with much of the recent activity concentrated in the Yakima Valley.

The infected Oregon herd was identified through the state's ongoing surveillance of dairy cattle for highly pathogenic avian influenza, according to the USDA. The agency said the herd had repeatedly tested negative under the National Milk Testing Strategy before this detection.

That detail is the most encouraging part of the announcement. The national milk testing program was built to find infections by sampling milk rather than waiting for farmers to notice sick cows, and here it appears to have done exactly that: it flagged a herd with a clean record. A system that only confirmed what everyone already knew would be of little use. This one caught a change.

The USDA said the detection does not alter its strategy. It urged producers to report livestock showing clinical signs of illness, along with any unusually sick or dead wildlife, to their state veterinarian.

Federal officials also moved to reassure consumers. "This detection does not pose a risk to consumer health or affect the safety of the commercial milk supply," the USDA said. The agency added that the Food and Drug Administration is confident pasteurization inactivates the virus and that the commercial, pasteurized milk supply is safe. That reassurance is specifically about pasteurized milk. Raw milk sits outside it, and federal health agencies have long warned about the risks of drinking it.

The more troubling development came from Washington. In a statement posted on X late Tuesday, United Farm Workers said H5N1 infections among Yakima Valley dairy workers are being widely underreported. The union cited several reasons. Many of the workers are immigrants, and the union pointed to an ongoing surge of U.S. Immigration and Customs Enforcement activity in the valley.

"Workers with milder symptoms are reluctant to be tested or miss work because sick cattle still need care," the union wrote. It also said: "Workers are very afraid of ICE-related retaliation if they don't follow employers' instructions."

The union said many more workers are sick than official counts reflect. It also said workers are being given only goggles and gloves for handling raw milk, which is where much of the exposure risk on an infected dairy lies. According to the union, symptoms range from a mild upper respiratory infection with pinkeye to severe flu-like illness with bone pain, a severe cough and a high fever.

The union was also careful about what it is not claiming. "We do not have reports that indicate human-to-human transmission, just workplace exposure to infected animals and milk," it said. That matters. The central fear with H5N1 has always been a virus that spreads easily between people, and nothing in the union's account points to that. What it describes is a workplace exposure problem that may be bigger than the official numbers show.

The union's claims have not been independently confirmed. Its account of why workers avoid testing is its own characterization, not an official finding.

According to the Centers for Disease Control and Prevention, the United States has recorded 74 human H5N1 cases since 2024, including three deaths. One of those deaths came earlier this month. A Yakima County resident with an underlying health condition died, and two other people were reported infected. All three had worked around dairy cows. It is the only U.S. H5N1 death recorded this year and the third since 2024.

The union's warning goes straight to how much weight that 74 can bear. Human case counts are one of the main tools public health officials use to judge how the virus behaves in people: how often it jumps from cows, how severe illness tends to be, and whether anything about the pattern is changing. If workers with mild illness stay home untested, or keep working because they fear the consequences of stepping away, the count captures mostly the people sick enough to seek care. The result would be fewer cases than reality and a skewed picture of how severe infections typically are.

The symptoms the union describes also fit what has been seen before. Many of the earliest dairy-linked human cases in 2024 involved conjunctivitis, or pinkeye, which is consistent with milk splashing into workers' eyes during milking. That history is part of why protective equipment matters so much in this outbreak. If the union's description of goggles and gloves alone is accurate, workers in a heavily affected valley may be facing raw milk with less protection than the risk calls for.

Taken together, the week's news points in two directions. The milk-testing system is doing its job on the animal side, finding infections in herds that had looked clean. On the human side, surveillance depends on people agreeing to be tested. If the union is right, the outbreak's biggest blind spot is on the dairy floor, among the workers closest to the virus, and not in the cattle data.