Bird flu keeps spreading on a Utah mink farm as officials hold off on culling or vaccinating

Bird flu has been spreading for more than two months on a Utah mink farm, and federal and state officials have not culled the animals, vaccinated them or put the farm under a formal quarantine, according to ProPublica reporting published October 23. It is the first documented outbreak of its kind in the United States, according to the Animal Welfare Institute.

What officials have said

ProPublica reported that Utah agriculture officials learned of the deaths in mid-August and that the U.S. Department of Agriculture’s dashboard showed seven captive mink had tested positive. The outbreak is on C&T Fenn Farms, a mink fur farm west of Provo, ProPublica reported. Sick mink carry the same strain that has spread through dairy herds, and officials told ProPublica they did not know whether contaminated beef caused the infections.

Records from the Utah Department of Agriculture and Food show seven avian influenza cases among captive mink, according to a Utah News Dispatch report carried by KSL on October 3. The department said its data may be incomplete. A public records request by the Animal Welfare Institute found the farm expected to lose about 80% of its mink, KSL reported.

Leon Page, a department public information officer, said there is no existing precedent for treating or responding to avian flu in mink. A state official told the Animal Welfare Institute: “our only options at this point are to watch them die or get emergency vaccine approval,” according to KSL.

No federal rules for mink

ProPublica reported that no federal rules cover sick mink. A USDA spokesperson told ProPublica the agency has no “species-specific regulatory authority or dedicated programs” for mink vaccination or depopulation. Poultry flocks are culled when one bird tests positive, ProPublica reported, and the USDA spokesperson said Congress would need to fund any mink depopulation program. Poultry culling has cost more than $1 billion since 2022, according to ProPublica.

State veterinarian Amanda Price issued a “verbal hold” on moving mink, manure or carcasses instead of a formal quarantine, ProPublica reported. KSL reported that the options under consideration are depopulation, quarantine and vaccination, and that only Agriculture Secretary Brooke Rollins can approve a vaccine. Page said there is little guidance on vaccine dosage or efficacy in mink.

According to ProPublica, Utah never seriously considered culling the mink after a fur trade representative warned that it would end the business. Finland and Spain depopulated mink farms with this strain, and experts told ProPublica Utah’s response was far slower.

Fenn told ProPublica the virus is still spreading, though more slowly. New samples were taken about two weeks before publication, and Price was still awaiting results.

Questions about worker exposure

Officials did not monitor or test workers, ProPublica reported. Utah public health officials stopped active monitoring after agriculture officials said farms objected, according to ProPublica. A worker with red eye, a symptom the Centers for Disease Control and Prevention says warrants testing, was not tested, ProPublica reported. The Utah County Health Department said the worker had gotten dust in his eye.

Page told KSL that human transmission “has not yet proven to be a high risk.” The Utah Department of Agriculture and Food cited the limited reach of the outbreak and the producer’s privacy in declining to answer some questions, KSL reported.

What experts say

Experts cited by ProPublica pointed to mink airways that contain human-type cell receptors, a 2024 study showing a single mutation could shift the virus toward human receptors, and an unusually early flu season in September that raises the risk of different flu viruses swapping genes.

Tom Peacock of the Pirbright Institute called the lack of an immediate culling decision “very concerning,” according to ProPublica. Erin Sorrell of Johns Hopkins said no one is leading a “one health” effort in Utah, ProPublica reported. Meghan Davis of Johns Hopkins said the outcome “really depends on what happens with the virus.”

Kate Dylewsky, assistant director of government affairs at the Animal Welfare Institute, told KSL: “It only takes one unlucky mutation of this dangerous virus to trigger a human health crisis.”

Earlier mink outbreaks

In 2020, COVID-19 killed about 12,000 mink in Utah, KSL reported. ProPublica reported that Utah responded more aggressively to COVID-19 on mink farms that year, including on this same farm.

Neil Vora, executive director of the Preventing Pandemics at the Source Coalition, wrote in a commentary for Think Global Health that Denmark culled about 17 million mink in 2020 after hundreds of people fell ill with mink-related COVID-19 strains. He wrote that H5N1 spread among mink in Spain in October 2022 and that about 50,000 mink were killed. U.S. mink production has fallen 80% since 2015, and fewer than 70 mink farms remain, with Utah second to Wisconsin, Vora wrote.