The strain of bird flu that’s ripped through American barns for the last four years has killed two people who caught it from sick animals. But as far as anyone can tell, humans can’t spread it. The virus has remained a true “bird” flu, tailored to attach to avian cells, not invade human throats and noses, where coughing and sneezing reliably spew droplets.

Under the right conditions, however, that could change. A single mutation could give the bird flu a foothold in people and spark a pandemic that experts fear could be deadlier than COVID-19.

For that to happen, this bird flu would likely need to find an intermediate host — an animal vulnerable to viruses that infect both birds and humans. These animals would be crowded together, each infection raising the odds that a new strain could arise through mutation. Then, for that strain to jump across species, it would have to have access to humans and time to spread among them undetected.

That perfect petri dish exists right now, a ProPublica investigation found. For over two months, an outbreak of bird flu has raged uncontrolled on a Utah farm that raises thousands of mink for fur. Mink have lungs and airways that on a cellular level are remarkably similar to those of people; they have caught and spread other flus and infected some humans with COVID-19.

Instead of trying to stop the outbreak and prevent it from spilling into humans, state and federal officials have done little except try to keep its existence quiet, our investigation shows. The failure to act amounts to a cascade of missteps flu experts called “irresponsible” and “puzzling.”One called it “playing with fire.”Utah agriculture officials learned in mid-August that mink were dying of bird flu on C&T Fenn Farms, about an hour’s drive south from Salt Lake City, according to communications released under the state’s public records law.

Had poultry been infected, the playbook would have been clear: The strain is so virulent that if a single chicken tests positive, the U.S. government requires farmers to kill the whole flock to protect other farms as well as public health. Poultry farmers are reimbursed for the loss. But there are no federal rules for how to deal with sick mink.

Handling Utah’s response was state veterinarian Amanda Price, who sought help from the U.S. Department of Agriculture, which takes the lead on bird flu outbreaks involving poultry and cows.

USDA officials said they didn’t regulate mink or have a vaccine that was approved to give them. And though officials with the Centers for Disease Control and Prevention spoke with Price’s health department counterparts who were less involved with the outbreak, they never talked to her, and she never reached out.

The threat of spillover has been far from the minds of Utah officials, records and interviews show. Instead, front and center have been the interests of a business raising animals to skin for luxury pelts to ship overseas.

“It has been devastating,” Price told ProPublica of the outbreak and its impact on the farm’s owner. “This is his life’s work that he’s seeing be destroyed. I really hope that you understand the humanity behind this situation.”Flu experts were unequivocal that the government should have ordered the farm to cull its mink, as other countries have done.

But Utah never seriously considered it. A fur trade representative warned Price that doing so would kill the business and, ultimately, the industry. Farms spend decades breeding mink to develop unique genetic lineages.

“There’s just not a lot of options out there other than kind of sitting and waiting and seeing what happens,” Price said, noting that USDA officials did not urge her to kill the mink or make her feel like bird flu in mink was any riskier than infections in other animals that have caught it, like ducks and cows. Flu experts found that response surprising.

“Every other country that I’m aware of that has had H5N1 in fur farms, depopulation has happened pretty quickly,” said Tom Peacock, an avian influenza researcher at the Pirbright Institute. “The fact that the first instinct wasn’t just to depopulate and figure stuff out later is very concerning to me.”And all the while, officials didn’t monitor the mink workers for symptoms, as guidance from the CDC urges.

Their exposure is significant: Mink sneeze. They escape. They attack. “The mink are fierce,” said a Spanish-speaking “minkero” who works on a nearby farm, showing the scars he got from the aggressive, solitary creatures. “You get scared because the fucking thing bites, and it claws at you.”Right now in Washington state, officials are working to track down the contacts of a symptomatic person exposed to dairy cattle infected with bird flu. The patient is isolating at home. Utah public health officials used to do similar, proactive monitoring. But they stopped after complaints from their colleagues in the agriculture department that farmers were annoyed by it.

“Us doing active monitoring was making it so that farms didn’t want to work with them,” said Pamela Gomez Pinedo, a respiratory disease epidemiologist for Utah’s health department. As a result, public health workers had a “pretty difficult time” getting details from agriculture officials, she said.

As part of a 2025 agreement, the Utah Department of Agriculture and Food agreed to share information about bird flu outbreaks on farms — so long as the health officials didn’t do anything to track workers’ health.

“We will only do active monitoring in the case of evidence of human-to-human transmission,” Pinedo said in emails with a CDC epidemiologist. As the outbreak stretched to a month, CDC officials expressed concerns, asking how anyone would know if a worker had been infected if they weren’t getting tested.

Price said the state’s policy not to monitor workers is meant to allow farmers to decide whether to contact the health department, rather than “forcing it on them.”“If we started seeing people actively dying from this, obviously that would change how we respond to this,” she said.

A telltale sign of bird flu infection in humans is eye redness. It is present in over 90% of cases and is often the sole symptom a person displays.

Last Saturday, a ProPublica reporter tracked down two people who worked at the Utah mink farm. One had a visibly red eye. The CDC explicitly urges testing for the symptom.

After ProPublica reached out to the farm, its owner, Chad Fenn, contacted the Utah County Health Department about the red eye, which had cleared up by Monday, he told ProPublica. He said the worker got dust in his eye; the department didn’t recommend testing.

“They’re not going to do anything,” Fenn said. “They said they don’t see that there’s a need.”He said the department recommended testing only if other symptoms, like a cough or sore throat, developed.

A half dozen flu experts had no shortage of adjectives to describe their disbelief at the government decisions not to cull the mink or monitor and test the workers.

“It’s amazing to me,” said Gail Hansen, a former Kansas state public health veterinarian and epidemiologist. “Utah doesn’t want to be the epicenter of the next human flu outbreak, right?”Most of the new viruses that have shaken humanity in the past century have spilled over from animals. Ebolas likely came from fruit bats; HIV, from chimpanzees. The leading theory for COVID-19 is that it jumped from bats to humans via an intermediate host mammal such as a raccoon dog. And all the modern flu pandemics have been bird flu viruses that mutated to spread in humans.

ProPublica reported extensively on spillover in a 2023 series called “Roots of an Outbreak.”To prevent more deadly spillovers, experts worldwide urge governments to take a “one health” approach to viral threats, treating dangers to animals as dangers to humans.

That’s not happening in Utah, experts said after reviewing ProPublica’s findings. Both the state and federal government are to blame.

“There’s no leader of this ‘one health’ team to take charge,” said Erin Sorrell, a senior scholar at the Johns Hopkins Center for Health Security. “That is going to allow the virus to continue to circulate, potentially adapt and potentially spill over into another host, whether it’s avian, mammalian or human.”This strain of bird flu, which began ripping through American poultry farms in early 2022, has proved adept at jumping to other species. It took hold in cows in 2024 and since then has run rampant through dairies.

Yet federal guidance to prevent the spread into mink farms hasn’t considered cows a threat. Farmers are encouraged to keep wild birds from infiltrating their barns and avoid feeding them raw poultry. It has said nothing about feeding beef parts to mink, which farmers commonly do in summer months to encourage the animals to put on weight and grow.

Dairy cows, which are not “depopulated” if exposed to bird flu, can still be slaughtered with the meat sold to farms and humans even though researchers have found the virus in the tissues of sick cows. USDA officials have insisted that beef for human consumption is free of bird flu, in part because the virus concentrates itself in sections of the cow people don’t usually eat. Fenn said that the mink are routinely fed raw organs of livestock, including cows.

The genomic data from the samples of mink lungs and brains sent from Utah to a USDA lab shows that the mink were stricken with the same strain of the virus that has spread in dairy herds. Officials said they didn’t know whether contaminated beef was the way the mink got infected.

In mink, the dairy strain of bird flu may have found a much better host for mutating into a human flu, because mink airways have an abundance of the type of cell receptors in people’s throats and noses that are a common pathway for infection.

A 2024 study of the dairy strain of the bird flu found that a single mutation could switch the virus from preferring the bird-type receptors to human-type receptors. And in studies using ferrets, a close relative of mink, the virus acquired mutations that let it attack human-type cell receptors.

It’s not clear to scientists just how much of an evolutionary leap would be needed for this strain of bird flu to spread among humans, or whether mink are the host that would allow that leap to happen.

How this ultimately plays out “really depends on what happens with the virus,” said Meghan Davis, an epidemiologist at Johns Hopkins University.

“We might get lucky, and a response that is not robust may not have dire consequences,” she said. “But we may get unlucky.”There’s also a risk of something called “reassortment,” where another flu virus could infect the same cell as a bird flu virus and swap wide swaths of genetic code already adapted to humans.

When the outbreak in the mink farm started, there was very little seasonal flu it could mix with, but September saw one of the earliest starts to flu season on record, compared with November, when flu normally takes off.

“The most likely scenario for a pandemic is that we have a virus that reassorts with another virus,” said Jennifer Nuzzo, director of the Pandemic Center at the Brown University School of Public Health. “Obviously, having this circulate amid human flu season is not great.”Utah officials were far more responsive to the threat of spillover in 2020, when outbreaks of COVID-19 spread explosively on mink farms – including this very farm. They invited federal officials to the state to research how the virus adapted and moved.

Given mink’s reputation as escape artists, wildlife experts set up traps around infected farms. The traps frequently caught mink carrying COVID-19 that had originated in the nearby barns. The virus infected both escaped mink and wildmink they had come in contact with. Mink and farmworkers were frequently tested, tracking the way that the virus was spreading and mutating.

As other states and countries took the same measures, they identified humans infected by the mink with COVID-19 and, ultimately, human-to-human transmission. There are no similar efforts now in Utah with bird flu.

A USDA spokesperson told ProPublica that it was more involved in 2020 because the virus that causes COVID-19 had “significant” potential to transmit between humans and animals and vice versa.

Scientists with the USDA sequenced and published bird flu genomic data from the first samples of dead mink. Those sequences didn’t show any particularly concerning mutations, experts and the CDC told ProPublica.

But in the past two months, experts said, the virus is sure to have continued mutating as it spread – it’s only a question of whether those mutations could confer some advantage in infecting humans as well.

“As long as it continues to go mink to mink, then it becomes more and more likely that it could jump to a human,” Hansen said. Fenn said new samples were taken two weeks ago. Price said she is still waiting for the results.

John Korslund, a retired USDA official who helped coordinate the response to COVID-19 on mink farms several years prior, was one of several experts who said officials need to look closely at newer genetic samples to see how the virus is evolving.

“I really want to know what the virus has done, from when it started to today,” he said. “Are we getting accumulated mutations making the virus more dangerous?”ProPublica began reporting on the outbreak late this summer after the USDA updated a bird flu dashboard that showed seven captive mink had tested positive in Utah. But neither the USDA nor state officials had said anything publicly, and, when asked, they wouldn’t discuss what was actually happening on the farm.

Communications obtained under the state’s public records law — first published by the Animal Welfare Institute and reported on by the Salt Lake Tribune — show Utah officials took pains to protect the farm’s privacy amid the outbreak. The state did not declare an emergency, because doing so, officials said, “may alert animal rights groups,” according to the messages.

Willy Lanier, a public health veterinarian with the state health department, told colleagues to keep the outbreak under “closer hold” than outbreaks of bird flu on poultry and dairy farms. Keeping the information confidential was consistent with state protocol, a spokesperson in his department said, adding that it was still shared with local health officials. But when ProPublica reached out to the spokesperson for the Utah County Health Department about a possible bird flu outbreak, she said, “That would be news to me.”Price is so deferential to the family that owns the farm that she has not set foot on the property.

“I’m really the only one here at this facility that’s been dealing with the producer. They’re a very private bunch,” Price said. “A lot of what I’m going off of is what I’ve seen from Google Maps, what I’ve talked to the producer about, what I’ve talked to the vet about. I haven’t felt the need to go out there based on those conversations.”She said she “became very comfortable” in conversations with the owner that the virus wouldn’t spread off the farm. It doesn’t have animals moving on and off over the course of the year like on a dairy or poultry farm; mink leave only when they’re slaughtered and skinned for pelts at the end of the year. She also said that she was confident the owner would recapture any escaped mink.

Short of a formal quarantine, Price gave the farm a “verbal hold” to not move any mink, or manure or carcasses, off the farm. “We haven’t seen spread off of this farm. We have not had additional cases in Utah that are linked to this, so thus far the verbal hold orders and the measures that have been taken look to be successful: There is not spread happening from this farm from this case.”Price’s assertion didn’t allay the concerns of experts that ProPublica spoke with.

When poultry test positive for this strain of bird flu, all nearby farms are quarantined and tested for the virus. But the approach in Utah relies on farms reporting cases or the public calling in reports of dead birds in the area.

“If you’re not looking for something, you won’t find it,” Sorrell said. “Unless you’re doing active surveillance, you can’t claim that you haven’t had cases.”Fenn told ProPublica his conversations with state officials made him less worried about any kind of spread. When the outbreak started, Fenn said, he asked whether the bird flu could infect people.

“Right off the bat, the state people we reported to, they said you don’t need to worry too much,” Fenn said. “My guys wear masks every day. They have glasses they can wear,” Fenn said. “ Me? I don’t wear it at all. Never have, never will, because I’ve been doing it for 40 years.”Fenn said he wished he could vaccinate the mink for bird flu to keep the rest of his animals from catching it and dying; Price asked the USDA about a vaccine that had been used to save endangered wild species but said she got nowhere with that request.

The USDA told ProPublica its division responsible for protecting animal health has no “species-specific regulatory authority or dedicated programs” for vaccinating mink, depopulating them or paying owners back for such a culling.

Fenn told ProPublica he thinks concerns about mink as a particularly risky bird flu host are trumped up by anti-fur activists, the same forces that he believed were behind the reactions in Spain and Finland, which depopulated mink farms hit with bird flu. “Europeans are a little scared of everything,” he said. “They’re going to do what they’re going to do, and here in the United States, we’re going to do what we’re going to do.”Price said she was aware that Finland and Spain had depopulated their fur farms when the same strain infected them.

“I didn’t really look much further into it,” she said, explaining that she was interested in those cases only for lessons about how to handle the outbreak, but not the particular reasons those countries chose to depopulate the farms.

A USDA spokesperson said Congress would have to specifically fund a program to depopulate mink. (The program to cull poultry to stop the spread of bird flu has cost well over $1 billion since 2022.) The events in Utah are a “clear warning sign” about the dangers of mink farms, said Neil Vora, executive director for the Preventing Pandemics at the Source Coalition.

“Fur farms are to produce pelts purely for luxury goods, to make fancy coats,” he said. “It’s absurd that we’re willing to gamble with the lives of millions of people just to keep an industry alive.”The industry has struggled as American consumers increasingly reject fur. Though domestic farms peaked about a decade ago, selling luxury pelts that often ended up in China, foreign farms have sprung up, threatening the business.

While animal rights advocates have pushed for Congress to adopt legislation that would phase out the fur industry, buying out farmers over the course of a year to end the practice once and for all, winds in Congress are blowing the other direction. The Senate will soon weigh in on the latest Farm Bill, which now seeks to expand market opportunities for mink farmers by undoing a prohibition in federal law on subsidizing the fur trade.

The virus continues to spread on the Utah farm, said Fenn, though at a slower pace. Experts told ProPublica it still poses a risk.

“I would want a full on hazmat suit if I were on that farm,” Peacock said. “Or, preferably, I’d rather not to be on that farm.”