For the first time, bird flu has been detected on a commercial dairy farm in Oregon. The Oregon Department of Agriculture on Tuesday confirmed a positive test for highly pathogenic avian influenza at a Morrow County dairy, and state officials have placed the farm under quarantine while they investigate how the cows became infected.
The detection came through the Oregon Department of Agriculture's routine statewide milk surveillance program, which began weekly testing in late 2024. State veterinarian Dr. Ryan Scholz said the finding was significant but not surprising. He said the virus is spreading among dairy cattle across the country. Scholz said in a statement that Oregon's milk surveillance program worked exactly as intended, identifying the infection quickly and allowing a rapid response with state and federal partners.
Bird flu was first detected in dairy cattle in March 2024 and has since been found in multiple states, including Washington, Idaho and California. The same virus has affected millions of poultry birds across the U.S. since 2022, including more than one million commercial and backyard chickens in Oregon, according to the U.S. Department of Agriculture. The virus was also detected last year in at least one pig and several wild mammals. Unlike in poultry, where the virus typically comes from wild migratory waterfowl, evidence suggests the virus in dairy cattle is mainly spreading from cow to cow.
Oregon health officials are monitoring farmworkers exposed to the infected animals. Dr. Melissa Sutton, medical director of respiratory viral pathogens at the Oregon Health Authority, said in a statement that with the use of appropriate personal protective equipment, the risk to farmworkers remains low. She added that the public health approach is focused on ensuring rapid testing and treatment for any individuals who develop symptoms to prevent severe disease.
According to the Centers for Disease Control and Prevention, the current public health risk to the general population remains low, although people working in close contact with dairy cattle or poultry are at higher risk. Officials say the nation's milk supply and other dairy products are safe to consume because pasteurization effectively inactivates the virus, and milk from sick animals is diverted or destroyed.
In Washington, the virus has spread rapidly, with at least 41 dairy farms testing positive over the last 30 days. A farmworker in Yakima County died earlier this month after contracting the virus, though human deaths linked to bird flu are very rare; health officials said the worker had underlying health conditions. Two other Yakima farmworkers contracted the virus but did not experience severe illness.
Analysis
Why This Matters
- First detection of bird flu in Oregon dairy cattle signals continued spread of the virus among livestock in the Pacific Northwest
- Raises monitoring and safety concerns for farmworkers and the dairy industry
- Oregon's milk surveillance program may serve as a model for early detection in other states
Background
Bird flu (highly pathogenic avian influenza) was first detected in U.S. dairy cattle in March 2024 and has since been confirmed in multiple states. While the virus primarily affects birds, it can jump to mammals, including cattle, pigs, and humans. Human infections are rare and generally linked to close contact with infected animals. Oregon had previously detected the virus in poultry and wild mammals, but this is the first confirmed case in dairy cattle.
Key Perspectives
Oregon Department of Agriculture: Dr. Ryan Scholz, state veterinarian, said the state's milk surveillance program worked exactly as intended, allowing rapid identification and response.
Oregon Health Authority: Dr. Melissa Sutton said the risk to farmworkers remains low with appropriate protective equipment, and the focus is on rapid testing and treatment.
Centers for Disease Control and Prevention: Maintains that the public health risk to the general population is low, but people working closely with dairy cattle or poultry are at higher risk.
What to Watch
- The investigation into how the Morrow County cows became infected and whether other farms test positive
- Health monitoring of exposed farmworkers for symptoms
- Any further spread within Oregon or neighboring states, including Washington's ongoing outbreak
Checked
12 claims in this story checked against 1 source: 12 supported.
Show each claim
- SupportedBird flu was detected on a commercial dairy farm in Oregon for the first time.OPB: “For the first time, bird flu has been detected on a commercial dairy farm in Oregon.”
- SupportedThe Morrow County farm is under quarantine.OPB: “Oregon agriculture officials say they’ve put the Morrow County farm under quarantine”
- SupportedOfficials say the nation’s milk supply and other dairy products are safe to consume.OPB: “Officials maintain the nation’s milk supply and other dairy products are safe to consume since pasteurization effectively inactivates the virus.”
- SupportedOn Tuesday, the Oregon Department of Agriculture confirmed a positive test for highly pathogenic avian influenza at a Morrow County dairy.OPB: “On Tuesday, the Oregon Department of Agriculture confirmed a positive test result for the virus, known as highly pathogenic avian influenza, at a Morrow County dairy.”
- SupportedOfficials will investigate how the cows got sick.OPB: “Oregon agriculture officials say they’ve put the Morrow County farm under quarantine and will continue to investigate how the cows got sick.”
- SupportedThe detection came through Oregon’s routine statewide milk surveillance program, which began weekly testing in late 2024.OPB: “Oregon officials first discovered the virus in Morrow County through the state Department of Agriculture’s routine statewide milk surveillance program, which began weekly testing in late 2024.”
- SupportedScholz said the surveillance program worked as intended, identifying the infection quickly and allowing a rapid response with state and federal partners.OPB: ““Oregon’s milk surveillance program worked exactly as intended, identifying this infection quickly and allowing us to respond rapidly with our state and federal partners,” Scholz said in a statement.”
- SupportedScholz said the virus is spreading among dairy cattle across the country.OPB: “The virus is spreading among dairy cattle across the country, he said.”
- SupportedMore than one million commercial and backyard chickens in Oregon have been affected by the virus since 2022.OPB: “This is the same virus that has affected millions of poultry birds across the U.S. since 2022, including more than one million commercial and backyard chickens in Oregon, according to the U.S. Department of Agriculture .”
- SupportedOregon health officials are monitoring farmworkers exposed to the infected animals.OPB: “But they are monitoring farmworkers exposed to the infected animals and will keep checking them for symptoms, said Dr. Melissa Sutton”
- SupportedSutton said appropriate personal protective equipment keeps the risk to farmworkers low.OPB: ““With the use of appropriate personal protective equipment, the risk to farm workers remains low,” Sutton said in a statement.”
- SupportedAt least 41 dairy farms in Washington tested positive for bird flu over the last 30 days.OPB: “In Washington, the virus has spread rapidly with at least 41 dairy farms testing positive for bird flu over the last 30 days.”