Do Cats With Bird Flu Pose a Health Risk to Humans?

By Sarah Boden, KFF Health News

More than 80 domestic cats, among many other types of mammals, have been confirmed to have had bird flu since 2022 — generally barn cats that lived on dairy farms, as well as feral cats and pets that spend time outdoors and likely caught it by hunting diseased rodents or wild birds.

Now, a small but growing number of house cats have gotten sick from H5N1, the bird flu strain driving the current U.S. outbreak, after eating raw food or drinking unpasteurized milk. Some of those cats died.

The strain of bird flu currently circulating has not adapted to efficiently spread among people. And there have been no known cases of cat-to-human transmission during the current outbreak of H5N1.

Still, there’s always been the risk that cats, which are arguably only semi-domesticated, could bring home a disease from a midnight prowl.

“Companion animals, and especially cats, are 100% a public health risk in terms of the risk of zoonotic transmission to people,” said virologist Angela Rasmussen, who studies disease progression in emerging viruses at the University of Saskatchewan’s Vaccine and Infectious Disease Organization.

This is because we snuggle with and sleep in bed with our cats. When we’re not looking, cats drink from our water glasses and walk on kitchen counters. So, cat owners should be aware of the ongoing spread of bird flu. “By reducing the risk to your cats, you reduce the risk to yourself,” Rasmussen said.

Rasmussen doesn’t think pet owners should be afraid their cats will give them bird flu but said taking precautions is good for pets, and for public health.

Signs of bird flu in cats include runny nose and discharge around the eyes, explained Michael Q. Bailey, president-elect of the American Veterinary Medical Association.

H5N1 also causes neurological problems like dizziness and seizures, which are symptoms of rabies, too. Rabies is almost always fatal, and it poses a threat to human health, so any animal suspected of having the viral disease must be euthanized. Bailey encourages people to ensure pets are up-to-date on their vaccinations.

Veterinarian Jane Sykes, who specializes in infectious diseases in cats and dogs at the University of California-Davis School of Veterinary Medicine, said people should not assume it’s bird flu if their cat is sick — even if their animal spends time outdoors or eats a raw diet. Upper-respiratory illnesses are common in cats, while H5N1 is “still pretty rare.”

Sykes gives her indoor cat, Freckles, regular kibble exclusively. She told NPR and KFF Health News she has no concerns about Freckles getting H5N1 because the heating process of making dry or canned pet food kills viruses.

‘This Is a Very Scary Virus’

Some people feed their pets raw meat or unpasteurized milk because they think it’s a more nutritious or natural diet. The American Veterinary Medical Association’s website discourages this due to foodborne pathogens like salmonella and listeria, and now the highly pathogenic H5N1.

By keeping pets healthy, veterinarians play an essential role in protecting humans from zoonotic diseases. The American Veterinary Medical Association says the risk of H5N1 spilling over from a pet to a person is “considered extremely low, but not zero.”

State and local public health agencies, including those in Los Angeles County and Washington state, have issued similar warnings against raw food diets for pets.

Concerns for human health are partly why the FDA announced last month it is now requiring cat and dog food companies to update their safety plans to protect against bird flu.

This came after the Oregon Department of Agriculture discovered a cat that was “strictly an indoor cat” had contracted H5N1 and died after consuming a frozen turkey product made by the raw pet food brand Northwest Naturals. It stated that “tests confirmed a genetic match between the virus in the raw and frozen pet food and the infected cat.”

Northwest Naturals voluntarily recalled that batch of its frozen turkey-based product. The company told KFF Health News and NPR that the recall involved “a small product run” and that it has concerns about the accuracy of the Oregon Agriculture Department’s testing.

Los Angeles County’s public health department said five cats from two households tested positive for bird flu after drinking unpasteurized raw milk from the Raw Farm dairy in California’s Central Valley.

Raw Farm voluntarily recalled its milk and cream after retail products tested positive for H5N1, but it denies any food safety issues, calling the concern “a political issue.”

Veterinarians also warn pet owners not to allow cats unsupervised time outside as there’s the risk of them getting H5N1 by interacting with other animals that might carry the disease.

“This is a very scary virus, given that it can infect so many different host species,” said Bruce Kornreich, director of Cornell University’s Feline Health Center.

At least one instance of a cat infecting a person with bird flu occurred in 2016. As NPR reported, a veterinarian in New York City caught the virus after having close contact with infected cats. The vet experienced mild symptoms and quickly recovered.

In that case, the strain of bird flu was H7N2, not the H5N1 that is now circulating in the U.S.

H7N2 is a very different type of virus, Sykes explained. But she said it shows that cat-to-human transmission of avian influenza is theoretically possible.

There isn’t a lot of research on transmission of bird flu from companion animals like cats or dogs to humans, though Rasmussen agreed it’s definitely a concern: The more infections you have in animals, “the more your luck is potentially going to run out.”

Most people who have caught H5N1 are agricultural workers who had direct contact with infected poultry or cattle. Of at least 67 confirmed human cases of H5N1 in the U.S., there’s been one fatality in an immunocompromised person who had contact with birds.

In general, zoonotic disease researchers want more H5N1 surveillance in companion animals of all types. Even if the human death toll of H5N1 remains relatively low, it remains a public health risk.

Virus Mutation

Part of the concern with this H5N1 outbreak is that bird flu viruses change. Just a few mutations could make this strain adept at spreading between people. And the more people who catch H5N1, the more likely it would adapt to be more efficient, said Suresh Kuchipudi, a virologist at the University of Pittsburgh School of Public Health, where he researches zoonotic diseases. Kuchipudi has studied H5N1 in cats.

Another concern is something called reassortment. If an animal or person is infected with two viruses at once, the viruses can trade genetic material, creating something new. This is common in influenza, so virologists are on the lookout for a case in which the bird flu reassorts to make a virus that’s far more contagious, and potentially more virulent.

Virologist Rasmussen is way more worried about this happening in pigs. Human respiratory physiology is more like that of swines than felines. So far, the current outbreak of H5N1 has not reached commercial hog operations. Rasmussen hopes it stays that way.

Kuchipudi said that reassortments are relatively rare events, but the outcome is completely unpredictable. Sometimes the results are benign, though it was likely a reassortment that involved an avian virus that led to the 1918 flu pandemic, which killed an estimated 50 million people. In the century since, virologists have established a global surveillance network to monitor influenza viruses. Scientists say continued investment in this network is key to preparing for and hopefully preventing another pandemic.

Winter is “reassortment season” because of all the influenza viruses circulating, Rasmussen said. A reassortment in cats could technically be possible since these pets occasionally get seasonal flu, but it’s highly unlikely. Rather, Rasmussen said, it’s more likely that a cat would pass H5N1 to a human who already has seasonal flu, and then a reassortment happens in the sick person. While the risk isn’t zero, Rasmussen doubts this will happen. It would depend on how ill the human was, and how much virus they’re exposed to from their cat.

“Unless the cat is really shedding a ton of virus, and you’re kind of making out with the cat, I think it would be hard,” she said.

Rasmussen and Kuchipudi caution there isn’t enough research to know for sure how much virus cats shed, or even how they shed the virus.

The Centers for Disease Control and Prevention was poised to release a new study about H5N1 in cats, but that was delayed when the Trump administration paused the Morbidity and Mortality Weekly Report. That investigation, revealed through emails obtained by KFF Health News in a public records request, found that house cats likely got bird flu from dairy workers.

Scientists and public health agencies should question previously held assumptions about bird flu, Kuchipudi urged. He noted that 20 years ago nobody would have predicted that bird flu would infect dairy cattle as it is now.

Dogs Have Lower Risk

The FDA says other domesticated animals, including dogs, can get bird flu infections. There are no confirmed cases of H5N1 among dogs in the U.S., though in other countries they have died from the virus.

There’s some disagreement and an overall lack of research on whether cat biology makes them more susceptible to H5N1 than other mammals, including humans, pigs, or dogs.

But cat behaviors, such as their love of dairy and predation of wild birds, put them at higher risk, Kuchipudi said. Also, living in groups might play a role as there are more feral cat colonies in the U.S. than packs of stray dogs.

There’s very little people can do about the H5N1 circulating in wild birds. As Rasmussen explained, “It’s flying around in the skies. It’s migrating north and south with the seasons.”

But she said there’s a lot people can do to keep the virus out of their homes.

That includes limiting a pet’s exposure to H5N1 by not feeding them raw food or unpasteurized milk, and trying to keep them from interacting with animals like rodents and wild birds that could be infected with the virus.

This article is from a partnership that includes NPR and KFF Health News, a national newsroom that produces in-depth journalism about health issues.  

Trump Administration Delays Release of Bird Flu Studies

By Amy Maxmen, KFF Health News

The Trump administration has intervened in the release of important studies on the bird flu, as an outbreak escalates across the United States.

One of the studies would reveal whether veterinarians who treat cattle have been unknowingly infected by the bird flu virus. Another report documents cases in which people carrying the virus might have infected their pet cats.

The studies were slated to appear in the official journal of the Centers for Disease Control and Prevention, the Morbidity and Mortality Weekly Report. The distinguished journal has been published without interruption since 1952.

Its scientific reports have been swept up in an “immediate pause” on communications by federal health agencies ordered by Dorothy Fink, the acting secretary of the Department of Health and Human Services. Fink’s memo covers “any document intended for publication,” she wrote, “until it has been reviewed and approved by a presidential appointee.” It was sent on President Donald Trump’s first full day in office.

That’s concerning, former CDC officials said, because a firewall has long existed between the agency’s scientific reports and political appointees.

“MMWR is the voice of science,” said Tom Frieden, a former CDC director and the CEO of the nonprofit organization Resolve to Save Lives.

“This idea that science cannot continue until there’s a political lens over it is unprecedented,” said Anne Schuchat, a former principal deputy director at the CDC. “I hope it’s going to be very short-lived, but if it’s not short-lived, it’s censorship.”

White House officials meddled with scientific studies on covid-19 during the first Trump administration, according to interviews and emails collected in a 2022 report from congressional investigators. Still, the MMWR came out as scheduled.

“What’s happening now is quite different than what we experienced in covid, because there wasn’t a stop in the MMWR and other scientific manuscripts,” Schuchat said.

Neither the White House nor HHS officials responded to requests for comment. CDC spokesperson Melissa Dibble said, “This is a short pause to allow the new team to set up a process for review and prioritization.”

News of the interruption hit suddenly last week, just as Fred Gingrich, executive director of the American Association of Bovine Practitioners, a group for veterinarians specializing in cattle medicine, was preparing to hold a webinar with members. He planned to disclose the results of a study he helped lead, slated for publication in the MMWR later that week.

Back in September, about 150 members had answered questions and donated blood for the study. Researchers at the CDC analyzed the samples for antibodies against the bird flu virus, to learn whether the veterinarians had been unknowingly infected earlier last year.

Although it would be too late to treat prior cases, the study promised to help scientists understand how the virus spreads from cows to people, what symptoms it causes, and how to prevent infection. “Our members were very excited to hear the results,” Gingrich said.

Like farmworkers, livestock veterinarians are at risk of bird flu infections. The study results could help protect them. And having fewer infections would lessen the chance of the H5N1 bird flu virus evolving within a person to spread efficiently between people — the gateway to a bird flu pandemic.

At least 67 people have tested positive for the bird flu in the U.S., with the majority getting the virus from cows or poultry. But studies and reporting suggest many cases have gone undetected, because testing has been patchy.

Just before the webinar, Gingrich said, the CDC informed him that because of an HHS order, the agency was unable to publish the report last week or communicate its findings. “We had to cancel,” he said.

Another bird flu study slated to be published in the MMWR last week concerns the possibility that people working in Michigan’s dairy industry infected their pet cats. These cases were partly revealed last year in emails obtained by KFF Health News. In one email from July 22, an epidemiologist pushed to publish the group’s investigation to “inform others about the potential for indirect transmission to companion animals.”

Jennifer Morse, medical director at the Mid-Michigan District Health Department and a scientist on the pending study, said she got a note from a colleague last week saying that “there are delays in our publication — outside of our control.”

A person close to the CDC, speaking on the condition of anonymity because of concerns about reprisal, expected the MMWR to be on hold at least until Feb. 6. The journal typically posts on Thursdays, and the HHS memo says the pause will last through Feb. 1.

“It’s startling,” Frieden said. He added that it would become dangerous if the reports aren’t restored. “It would be the equivalent of finding out that your local fire department has been told not to sound any fire alarms,” he said.

In addition to publishing studies, the MMWR keeps the country updated on outbreaks, poisonings, and maternal mortality, and provides surveillance data on cancer, heart disease, HIV, and other maladies. Delaying or manipulating the reports could harm Americans by stunting the ability of the U.S. government to detect and curb health threats, Frieden said.

The freeze is also a reminder of how the first Trump administration interfered with the CDC’s reports on covid, revealed in emails detailed in 2022 by congressional investigators with the House Select Subcommittee on the Coronavirus Crisis. That investigation found that political appointees at HHS altered or delayed the release of five reports and attempted to control several others in 2020.

In one instance, Paul Alexander, then a scientific adviser to HHS, criticized a July 2020 report on a coronavirus outbreak at a Georgia summer camp in an email to MMWR editors, which was disclosed in the congressional investigation.

“It just sends the wrong message as written and actually reads as if to send a message of NOT to re-open,” he wrote. Although the report’s data remained the same, the CDC removed remarks on the implications of the findings for schools.

Later that year, Alexander sent an email to then-HHS spokesperson Michael Caputo citing this and another example of his sway over the reports: “Small victory but a victory nonetheless and yippee!!!”

Schuchat, who was at the CDC at the time, said she had never experienced such attempts to spin or influence the agency’s scientific reports in more than three decades with the agency. She hopes it won’t happen again. “The MMWR cannot become a political instrument,” she said.

Gingrich remains hopeful that the veterinary study will come out soon. “We’re an apolitical organization,” he said. “Maintaining open lines of communication and continuing research with our federal partners is critical as we fight this outbreak.”

KFF Health News is a national newsroom that produces in-depth journalism about health issues.  

How U.S. Set the Stage for a Bird Flu Pandemic

By Amy Maxmen, KFF Health News

Keith Poulsen’s jaw dropped when farmers showed him images on their cellphones at the World Dairy Expo in Wisconsin in October. A livestock veterinarian at the University of Wisconsin, Poulsen had seen sick cows before, with their noses dripping and udders slack.

But the scale of the farmers’ efforts to treat the sick cows stunned him. They showed videos of systems they built to hydrate hundreds of cattle at once. In 14-hour shifts, dairy workers pumped gallons of electrolyte-rich fluids into ailing cows through metal tubes inserted into the esophagus.

“It was like watching a field hospital on an active battlefront treating hundreds of wounded soldiers,” he said.

Nearly a year into the first outbreak of the bird flu among cattle, the virus shows no sign of slowing. The U.S. government failed to eliminate the virus on dairy farms when it was confined to a handful of states, by quickly identifying infected cows and taking measures to keep their infections from spreading. Now at least 875 herds across 16 states have tested positive.

Experts say they have lost faith in the government’s ability to contain the outbreak.

“We are in a terrible situation and going into a worse situation,” said Angela Rasmussen, a virologist at the University of Saskatchewan in Canada. “I don’t know if the bird flu will become a pandemic, but if it does, we are screwed.”

To understand how the bird flu got out of hand, KFF Health News interviewed nearly 70 government officials, farmers and farmworkers, and researchers with expertise in virology, pandemics, veterinary medicine, and more.

Together with emails obtained from local health departments through public records requests, this investigation revealed key problems, including deference to the farm industry, eroded public health budgets, neglect for the safety of agriculture workers, and the sluggish pace of federal interventions.

Case in point: The U.S. Department of Agriculture this month announced a federal order to test milk nationwide. Researchers welcomed the news but said it should have happened months ago — before the virus was so entrenched.

“It’s disheartening to see so many of the same failures that emerged during the covid-19 crisis reemerge,” said Tom Bollyky, director of the Global Health Program at the Council on Foreign Relations.

Far more bird flu damage is inevitable, but the extent of it will be left to the Trump administration and Mother Nature.

Already, the USDA has funneled more than $1.7 billion into tamping down the bird flu on poultry farms since 2022, which includes reimbursing farmers who’ve had to cull their flocks, and more than $430 million into combating the bird flu on dairy farms.

In coming years, the bird flu may cost billions of dollars more in expenses and losses. Dairy industry experts say the virus kills roughly 2% to 5% of infected dairy cows and reduces a herd’s milk production by about 20%.

Worse, the outbreak poses the threat of a pandemic. More than 60 people in the U.S. have been infected, mainly by cows or poultry, but cases could skyrocket if the virus evolves to spread efficiently from person to person. And the recent news of a person critically ill in Louisiana with the bird flu shows that the virus can be dangerous.

RUNNY NOSE OF DAIRY COW

Just a few mutations could allow the bird flu to spread between people. Because viruses mutate within human and animal bodies, each infection is like a pull of a slot machine lever.

“Even if there’s only a 5% chance of a bird flu pandemic happening, we’re talking about a pandemic that probably looks like 2020 or worse,” said Tom Peacock, a bird flu researcher at the Pirbright Institute in the United Kingdom, referring to covid. “The U.S. knows the risk but hasn’t done anything to slow this down,” he added.

Beyond the bird flu, the federal government’s handling of the outbreak reveals cracks in the U.S. health security system that would allow other risky new pathogens to take root.

“This virus may not be the one that takes off,” said Maria Van Kerkhove, director of the emerging diseases group at the World Health Organization. “But this is a real fire exercise right now, and it demonstrates what needs to be improved.”

A Slow Start

It may have been a grackle, a goose, or some other wild bird that infected a cow in northern Texas. In February, the state’s dairy farmers took note when cows stopped making milk. They worked alongside veterinarians to figure out why. In less than two months, veterinary researchers identified the highly pathogenic H5N1 bird flu virus as the culprit.

Long listed among pathogens with pandemic potential, the bird flu’s unprecedented spread among cows marked a worrying shift. It had evolved to thrive in animals that are more like people biologically than birds.

After the USDA announced the dairy outbreak on March 25, control shifted from farmers, veterinarians, and local officials to state and federal agencies. Collaboration disintegrated almost immediately.

Farmers worried the government might block their milk sales or even demand sick cows be killed, as poultry are, said Kay Russo, a livestock veterinarian in Fort Collins, Colorado.

Instead, Russo and other veterinarians said, they were dismayed by inaction. The USDA didn’t respond to their urgent requests to support studies on dairy farms — and for money and confidentiality policies to protect farmers from financial loss if they agreed to test animals.

The USDA announced that it would conduct studies itself. But researchers grew anxious as weeks passed without results. “Probably the biggest mistake from the USDA was not involving the boots-on-the-ground veterinarians,” Russo said.

Will Clement, a USDA senior adviser for communications, said in an email: “Since first learning of H5N1 in dairy cattle in late March 2024, USDA has worked swiftly and diligently to assess the prevalence of the virus in U.S. dairy herds.” The agency provided research funds to state and national animal health labs beginning in April, he added.

The USDA didn’t require lactating cows to be tested before interstate travel until April 29. By then, the outbreak had spread to eight other states. Farmers often move cattle across great distances, for calving in one place, raising in warm, dry climates, and milking in cooler ones. Analyses of the virus’s genes implied that it spread between cows rather than repeatedly jumping from birds into herds.

Milking equipment was a likely source of infection, and there were hints of other possibilities, such as through the air as cows coughed or in droplets on objects, like work boots. But not enough data had been collected to know how exactly it was happening. Many farmers declined to test their herds, despite an announcement of funds to compensate them for lost milk production in May.

“There is a fear within the dairy farmer community that if they become officially listed as an affected farm, they may lose their milk market,” said Jamie Jonker, chief science officer at the National Milk Producers Federation, an organization that represents dairy farmers. To his knowledge, he added, this hasn’t happened.

Speculation filled knowledge gaps. Zach Riley, head of the Colorado Livestock Association, said he suspected that wild birds may be spreading the virus to herds across the country, despite scientific data suggesting otherwise. Riley said farmers were considering whether to install “floppy inflatable men you see outside of car dealerships” to ward off the birds.

Advisories from agriculture departments to farmers were somewhat speculative, too. Officials recommended biosecurity measures such as disinfecting equipment and limiting visitors. As the virus kept spreading throughout the summer, USDA senior official Eric Deeble said at a press briefing, “The response is adequate.”

The USDA, the Centers for Disease Control and Prevention, and the Food and Drug Administration presented a united front at these briefings, calling it a “One Health” approach. In reality, agriculture agencies took the lead.

This was explicit in an email from a local health department in Colorado to the county’s commissioners. “The State is treating this primarily as an agriculture issue (rightly so) and the public health part is secondary,” wrote Jason Chessher, public health director in Weld County, Colorado. The state’s leading agriculture county, Weld’s livestock and poultry industry produces about $1.9 billion in sales each year.

Patchy Surveillance

In July, the bird flu spread from dairies in Colorado to poultry farms. To contain it, two poultry operations employed about 650 temporary workers — Spanish-speaking immigrants as young as 15 — to cull flocks. Inside hot barns, they caught infected birds, gassed them with carbon dioxide, and disposed of the carcasses. Many did the hazardous job without goggles, face masks, and gloves.

By the time Colorado’s health department asked if workers felt sick, five women and four men had been infected. They all had red, swollen eyes — conjunctivitis — and several had such symptoms as fevers, body aches, and nausea.

State health departments posted online notices offering farms protective gear, but dairy workers in several states told KFF Health News that they had none. They also hadn’t heard about the bird flu, never mind tests for it.

Studies in Colorado, Michigan, and Texas would later show that bird flu cases had gone under the radar. In one analysis, eight dairy workers who hadn’t been tested — 7% of those studied — had antibodies against the virus, a sign that they had been infected.

Missed cases made it impossible to determine how the virus jumped into people and whether it was growing more infectious or dangerous.

“I have been distressed and depressed by the lack of epidemiologic data and the lack of surveillance,” said Nicole Lurie, an executive director at the international organization the Coalition for Epidemic Preparedness Innovations, who served as assistant secretary for preparedness and response in the Obama administration.

Citing “insufficient data,” the British government raised its assessment of the risk posed by the U.S. dairy outbreak in July from three to four on a six-tier scale.

Virologists around the world said they were flabbergasted by how poorly the United States was tracking the situation. “You are surrounded by highly pathogenic viruses in the wild and in farm animals,” said Marion Koopmans, head of virology at Erasmus Medical Center in the Netherlands. “If three months from now we are at the start of the pandemic, it is nobody’s surprise.”

Although the bird flu is not yet spreading swiftly between people, a shift in that direction could cause immense suffering. The CDC has repeatedly described the cases among farmworkers this year as mild — they weren’t hospitalized. But that doesn’t mean symptoms are a breeze, or that the virus can’t cause worse.

“It does not look pleasant,” wrote Sean Roberts, an emergency services specialist at the Tulare County, California, health department in an email to colleagues in May. He described photographs of an infected dairy worker in another state: “Apparently, the conjunctivitis that this is causing is not a mild one, but rather ruptured blood vessels and bleeding conjunctiva.”

Over the past 30 years, half of around 900 people diagnosed with bird flu around the world have died. Even if the case fatality rate is much lower for this strain of the bird flu, covid showed how devastating a 1% death rate can be when a virus spreads easily.

Like other cases around the world, the person now hospitalized with the bird flu in Louisiana appears to have gotten the virus directly from birds. After the case was announced, the CDC released a statement saying, “A sporadic case of severe H5N1 bird flu illness in a person is not unexpected.”

‘The Cows Are More Valuable Than Us’

Local health officials were trying hard to track infections, according to hundreds of emails from county health departments in five states. But their efforts were stymied. Even if farmers reported infected herds to the USDA and agriculture agencies told health departments where the infected cows were, health officials had to rely on farm owners for access.

“The agriculture community has dictated the rules of engagement from the start,” said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota. “That was a big mistake.”

Some farmers told health officials not to visit and declined to monitor their employees for signs of sickness. Sending workers to clinics for testing could leave them shorthanded when cattle needed care. “Producer refuses to send workers to Sunrise [clinic] to get tested since they’re too busy. He has pinkeye, too,” said an email from the Weld, Colorado, health department.

“We know of 386 persons exposed — but we know this is far from the total,” said an email from a public health specialist to officials at Tulare’s health department recounting a call with state health officials. “Employers do not want to run this through worker’s compensation. Workers are hesitant to get tested due to cost,” she wrote.

Jennifer Morse, medical director of the Mid-Michigan District Health Department, said local health officials have been hesitant to apply pressure after the backlash many faced at the peak of covid. Describing the 19 rural counties she serves as “very minimal-government-minded,” she said, “if you try to work against them, it will not go well.”

Rural health departments are also stretched thin. Organizations that specialize in outreach to farmworkers offered to assist health officials early in the outbreak, but months passed without contracts or funding. During the first years of covid, lagging government funds for outreach to farmworkers and other historically marginalized groups led to a disproportionate toll of the disease among people of color.

Kevin Griffis, director of communications at the CDC, said the agency worked with the National Center for Farmworker Health throughout the summer “to reach every farmworker impacted by H5N1.” But Bethany Boggess Alcauter, the center’s director of public health programs, said it didn’t receive a CDC grant for bird flu outreach until October, to the tune of $4 million. Before then, she said, the group had very limited funds for the task. “We are certainly not reaching ‘every farmworker,’” she added.

Farmworker advocates also pressed the CDC for money to offset workers’ financial concerns about testing, including paying for medical care, sick leave, and the risk of being fired. This amounted to an offer of $75 each. “Outreach is clearly not a huge priority,” Boggess said. “I hear over and over from workers, ‘The cows are more valuable than us.’”

The USDA has so far put more than $2.1 billion into reimbursing poultry and dairy farmers for losses due to the bird flu and other measures to control the spread on farms. Federal agencies have also put $292 million into developing and stockpiling bird flu vaccines for animals and people. In a controversial decision, the CDC has advised against offering the ones on hand to farmworkers.

“If you want to keep this from becoming a human pandemic, you focus on protecting farmworkers, since that’s the most likely way that this will enter the human population,” said Peg Seminario, an occupational health researcher in Bethesda, Maryland. “The fact that this isn’t happening drives me crazy.”

Nirav Shah, principal deputy director of the CDC, said the agency aims to keep workers safe. “Widespread awareness does take time,” he said. “And that’s the work we’re committed to doing.”

As President-elect Donald Trump comes into office in January, farmworkers may be even less protected. Trump’s pledge of mass deportations will have repercussions whether they happen or not, said Tania Pacheco-Werner, director of the Central Valley Health Policy Institute in California.

Many dairy and poultry workers are living in the U.S. without authorization or on temporary visas linked to their employers. Such precarity made people less willing to see doctors about covid symptoms or complain about unsafe working conditions in 2020. Pacheco-Werner said, “Mass deportation is an astronomical challenge for public health.”

First Human-to-Human Transmission?

A switch flipped in September among experts who study pandemics as national security threats. A patient in Missouri had the bird flu, and no one knew why. “Evidence points to this being a one-off case,” Shah said at a briefing with journalists. About a month later, the agency revealed it was not.

Antibody tests found that a person who lived with the patient had been infected, too. The CDC didn’t know how the two had gotten the virus, and the possibility of human transmission couldn’t be ruled out.

Nonetheless, at an October briefing, Shah said the public risk remained low and the USDA’s Deeble said he was optimistic that the dairy outbreak could be eliminated.

Experts were perturbed by such confident statements in the face of uncertainty, especially as California’s outbreak spiked and a child was mysteriously infected by the same strain of virus found on dairy farms.

“This wasn’t just immaculate conception,” said Stephen Morrison, director of the Global Health Policy Center at the Center for Strategic and International Studies. “It came from somewhere and we don’t know where, but that hasn’t triggered any kind of reset in approach — just the same kind of complacency and low energy.”

Sam Scarpino, a disease surveillance specialist in the Boston area, wondered how many other mysterious infections had gone undetected. Surveillance outside of farms was even patchier than on them, and bird flu tests have been hard to get.

Although pandemic experts had identified the CDC’s singular hold on testing for new viruses as a key explanation for why America was hit so hard by covid in 2020, the system remained the same. Bird flu tests could be run only by the CDC and public health labs until this month, even though commercial and academic diagnostic laboratories had inquired about running tests since April. The CDC and FDA should have tried to help them along months ago, said Ali Khan, a former top CDC official who now leads the University of Nebraska Medical Center College of Public Health.

As winter sets in, the bird flu becomes harder to spot because patient symptoms may be mistaken for the seasonal flu. Flu season also raises a risk that the two flu viruses could swap genes if they infect a person simultaneously. That could form a hybrid bird flu that spreads swiftly through coughs and sneezes.

A sluggish response to emerging outbreaks may simply be a new, unfortunate norm for America, said Bollyky, at the Council on Foreign Relations. If so, the nation has gotten lucky that the bird flu still can’t spread easily between people. Controlling the virus will be much harder and costlier than it would have been when the outbreak was small. But it’s possible.

Agriculture officials could start testing every silo of bulk milk, in every state, monthly, said Poulsen, the livestock veterinarian. “Not one and done,” he added. If they detect the virus, they’d need to determine the affected farm in time to stop sick cows from spreading infections to the rest of the herd — or at least to other farms. Cows can spread the bird flu before they’re sick, he said, so speed is crucial.

Curtailing the virus on farms is the best way to prevent human infections, said Jennifer Nuzzo, director of the Pandemic Center at Brown University, but human surveillance must be stepped up, too. Every clinic serving communities where farmworkers live should have easy access to bird flu tests — and be encouraged to use them. Funds for farmworker outreach must be boosted. And, she added, the CDC should change its position and offer farmworkers bird flu vaccines to protect them and ward off the chance of a hybrid bird flu that spreads quickly.

The rising number of cases not linked to farms signals a need for more testing in general. When patients are positive on a general flu test — a common diagnostic that indicates human, swine, or bird flu — clinics should probe more deeply, Nuzzo said.

The alternative is a wait-and-see approach in which the nation responds only after enormous damage to lives or businesses. This tack tends to rely on mass vaccination. But an effort analogous to Trump’s Operation Warp Speed is not assured, and neither is rollout like that for the first covid shots, given a rise in vaccine skepticism among Republican lawmakers.

Change may instead need to start from the bottom up — on dairy farms, still the most common source of human infections, said Poulsen. He noticed a shift in attitudes among farmers at the Dairy Expo: “They’re starting to say, ‘How do I save my dairy for the next generation?’ They recognize how severe this is, and that it’s not just going away.”

KFF Health News is a national newsroom that produces in-depth journalism about health issues.

‘We’re Flying Blind’: Response to Bird Flu Outbreak Mirrors Covid Errors

By Amy Maxmen, KFF Health News

It’s been nearly three months since the U.S. government announced an outbreak of the bird flu virus on dairy farms. The World Health Organization considers the virus a public health concern because of its potential to cause a pandemic, yet the U.S. has tested only about 45 people across the country.

“We’re flying blind,” said Jennifer Nuzzo, director of the Pandemic Center at the Brown University School of Public Health. With so few tests run, she said, it’s impossible to know how many farmworkers have been infected, or how serious the disease is. A lack of testing means the country might not notice if the virus begins to spread between people — the gateway to another pandemic.

“We’d like to be doing more testing. There’s no doubt about that,” said Nirav Shah, principal deputy director of the Centers for Disease Control and Prevention. The CDC’s bird flu test is the only one the Food and Drug Administration has authorized for use right now. Shah said the agency has distributed these tests to about 100 public health labs in states.

“We’ve got roughly a million available now,” he said, “and expect 1.2 million more in the next two months.”

But Nuzzo and other researchers are concerned because the CDC and public health labs aren’t generally where doctors order tests from. That job tends to be done by major clinical laboratories run by companies and universities, which lack authorization for bird flu testing.

As the outbreak grows — with at least 114 herds infected in 12 states as of June 18 — researchers said the CDC and FDA are not moving fast enough to remove barriers that block clinical labs from testing. In one case, the diagnostics company Neelyx Labs was on hold with a query for more than a month.

“Clinical labs are part of the nation’s public health system,” said Alex Greninger, assistant director of the University of Washington Medicine Clinical Virology Laboratory. “Pull us into the game. We’re stuck on the bench.”

The CDC recognized the need for clinical labs in a June 10 memo. It calls on industry to develop tests for the H5 strain of bird flu virus, the one circulating among dairy cattle.

“The limited availability and accessibility of diagnostic tests for Influenza A(H5) poses several pain points,” the CDC wrote. The points include a shortage of tests if demand spikes.

Testing Failures Made Pandemic Worse

Researchers, including former CDC director Tom Frieden and Anthony Fauci, who led the nation’s response to covid, cite testing failures as a key reason the U.S. fared so poorly with covid. Had covid tests been widely available in early 2020, they say, the U.S. could have detected many cases before they turned into outbreaks that prompted business shutdowns and cost lives.

In an article published this month, Nuzzo and a group of colleagues noted that the problem wasn’t testing capability but a failure to deploy that capability swiftly. The U.S. reported excess mortality eight times as high as other countries with advanced labs and other technological advantages.

A covid test vetted by the WHO was available by mid-January 2020. Rather than use it, the United States stuck to its own multistage process, which took several months. Namely, the CDC develops its own test then sends it to local public health labs. Eventually, the FDA authorizes tests from clinical diagnostic labs that serve hospital systems, which must then scale up their operations. That took time, and people died amid outbreaks at nursing homes and prisons, waiting on test results.

In contrast, South Korea immediately rolled out testing through private sector laboratories, allowing it to keep schools and businesses open. “They said, ‘Gear up, guys; we’re going to need a ton of tests,’” said Frieden, now president of the public health organization Resolve to Save Lives. “You need to get commercials in the game.” 

Nuzzo and her colleagues describe a step-by-step strategy for rolling out testing in health emergencies, in response to mistakes made obvious by covid. But in this bird flu outbreak, the U.S. is weeks behind that playbook.

Ample testing is critical for two reasons. First, people need to know if they’re infected so that they can be quickly treated, Nuzzo said. Over the past two decades, roughly half of about 900 people around the globe known to have gotten the bird flu died from it.

Although the three farmworkers diagnosed with the disease this year in the United States had only mild symptoms, like a runny nose and inflamed eyes, others may not be so lucky. The flu treatment Tamiflu works only when given soon after symptoms start.

The CDC and local health departments have tried to boost bird flu testing among farmworkers, asking them to be tested if they feel sick. Farmworker advocates list several reasons why their outreach efforts are failing. The outreach might not be in the languages the farmworkers speak, for example, or address such concerns as a loss of employment.

If people who live and work around farms simply see a doctor when they or their children fall ill, those cases could be missed if the doctors send samples to their usual clinical laboratories. The CDC has asked doctors to send samples from people with flu symptoms who have exposure to livestock or poultry to public health labs.

“If you work on a farm with an outbreak and you’re worried about your welfare, you can get tested,” Shah said.

But sending samples to public health departments requires knowledge, time, and effort.

“I really worry about a testing scheme in which busy clinicians need to figure this out,” Nuzzo said.

‘Get Prepared Before Things Get Crazy’

The other reason to involve clinical laboratories is so the nation can ramp up testing if the bird flu is suddenly detected among people who didn’t catch it from cattle. There’s no evidence the virus has started to spread among people, but that could change in coming months as it evolves.

The fastest way to get clinical labs involved, Greninger said, is to allow them to use a test the FDA has already authorized: the CDC’s bird flu test. On April 16 the CDC opened up that possibility by offering royalty-free licenses for components of its bird flu tests to accredited labs.

Several commercial labs asked for licenses. “We want to get prepared before things get crazy,” said Shyam Saladi, chief executive officer of the diagnostics company Neelyx Labs, which offered covid and mpox tests during shortages in those outbreaks. His experience over the past two months reveals the types of barriers that prevent labs from moving swiftly.

In email exchanges with the CDC, shared with KFF Health News, Saladi specifies the labs’ desire for licenses relevant to the CDC’s test, as well as a “right to reference” the CDC’s data in its application for FDA authorization.

That “right to reference” makes it easier for one company to use a test developed by another. It allows the new group to skip certain analyses conducted by the original maker, by telling the FDA to look at data in the original FDA application. This was commonplace with covid tests at the peak of the pandemic.

At first, the CDC appeared eager to cooperate. “A right of reference to the data should be available,” Jonathan Motley, a patent specialist at the CDC, wrote in an email to Saladi on April 24. Over the next few weeks, the CDC sent him information about transferring its licenses to the company, and about the test, which prompted Neelyx’s researchers to buy testing components and try out the CDC’s process on their equipment.

But Saladi grew increasingly anxious about the ability to reference the CDC’s data in the company’s FDA application. “Do you have an update with respect to the right of reference?” he asked the CDC on May 13. “If there are any potential sticking points with respect to this, would you mind letting us know please?”

He asked several more times in the following weeks, as the number of herds infected with the bird flu ticked upward and more cases among farmworkers were announced. “Given that it is May 24 and the outbreak has only expanded, can CDC provide a date by which it plans to respond?” Saladi wrote.

The CDC eventually signed a licensing agreement with Neelyx but informed Saladi that it would not, in fact, provide the reference. Without that, Saladi said, he could not move forward with the CDC’s test — at least not without more material from the agency. “It’s really frustrating,” he said. “We thought they really intended to support the development of these tests in case they are needed.”

Shah, from the CDC, said test manufacturers should generate their own data to prove that they’re using the CDC’s test correctly. “We don’t have a shortage such that we need to cut corners,” he said. “Quality reigns supreme.”

The CDC has given seven companies, including Neelyx, licenses for its tests — although none have been cleared to use them by the FDA. Only one of those companies asked for the right of reference, Shah said. The labs may be assisted by additional material that the agency is developing now, to allow them to complete the analyses — even without the reference.

“This should have happened sooner,” Saladi told KFF Health News when he was told about the CDC’s pending additional material. “There’s been no communication about this.”

Greninger said the delays and confusion are reminiscent of the early months of covid, when federal agencies prioritized caution over speed. Test accuracy is important, he said, but excessive vetting can cause harm in a fast-moving outbreak like this one. “The CDC should be trying to open this up to labs with national reach and a good reputation,” he said. “I fall on the side of allowing labs to get ready — that’s a no-brainer.”

Clinical laboratories have also begun to develop their own tests from scratch. But researchers said they’re moving cautiously because of a recent FDA rule that gives the agency more oversight of lab-developed tests, lengthening the pathway to approval. In an email to KFF Health News, FDA press officer Janell Goodwin said the rule’s enforcement will occur gradually.

However, Susan Van Meter, president of the American Clinical Laboratory Association, a trade group whose members include the nation’s largest commercial diagnostic labs, said companies need more clarity: “It’s slowing things down because it’s adding to the confusion about what is allowable.”

Creating tests for the bird flu is already a risky bet, because demand is uncertain. It’s not clear whether this outbreak in cattle will trigger an epidemic or fizzle out. In addition to issues with the CDC and FDA, clinical laboratories are trying to figure out whether health insurers or the government will pay for bird flu tests.

These wrinkles will be smoothed eventually. Until then, the vanishingly slim numbers of people tested, along with the lack of testing in cattle, may draw criticism from other parts of the world.

“Think about our judgment of China’s transparency at the start of covid,” Nuzzo said. “The current situation undermines America’s standing in the world.”

KFF Health News is a national newsroom that produces in-depth journalism about health issues.  

Lack of Testing Raises Risk of Bird Flu Pandemic

By Amy Maxmen and Arthur Allen, KFF Health News

Stanford University infectious disease doctor Abraar Karan has seen a lot of patients with runny noses, fevers, and irritated eyes lately. Such symptoms could signal allergies, covid, or a cold. This year, there’s another suspect, bird flu — but there’s no way for most doctors to know.

If the government doesn’t prepare to ramp up H5N1 bird flu testing, he and other researchers warn, the United States could be caught off guard again by a pandemic.

“We’re making the same mistakes today that we made with covid,” Deborah Birx, who served as former President Donald Trump’s coronavirus response coordinator, said June 4 on CNN.

To become a pandemic, the H5N1 bird flu virus would need to spread from person to person. The best way to keep tabs on that possibility is by testing people.

Scientifically speaking, many diagnostic laboratories could detect the virus. However, red tape, billing issues, and minimal investment are barriers to quickly ramping up widespread availability of testing. At the moment, the Food and Drug Administration has authorized only the Centers for Disease Control and Prevention’s bird flu test, which is used only for people who work closely with livestock.

State and federal authorities have detected bird flu in dairy cattle in 12 states. Three people who work on separate dairy farms tested positive, and it is presumed they caught the virus from cows. Yet researchers agree that number is an undercount given the CDC has tested only about 40 people for the disease.

“It’s important to know if this is contained on farms, but we have no information because we aren’t looking,” said Helen Chu, an infectious disease specialist at the University of Washington in Seattle who alerted the country to covid’s spread in 2020 by testing people more broadly.

Reports of untested sick farmworkers — as well as a maternity worker who had flu symptoms — in the areas with H5N1 outbreaks among cattle in Texas suggest the numbers are higher. And the mild symptoms of those who tested positive — a cough and eye inflammation, without a fever — are such that infected people might not bother seeking medical care and, therefore, wouldn’t be tested.

The CDC has asked farmworkers with flu symptoms to get tested, but researchers are concerned about a lack of outreach and incentives to encourage testing among people with limited job security and access to health care. Further, by testing only on dairy farms, the agency likely would miss evidence of wider spread.

“It’s hard to not compare this to covid, where early on we only tested people who had traveled,” said Benjamin Pinsky, medical director of the clinical virology laboratory at Stanford University. “That left us open to not immediately recognizing that it was transmitting among the community.”

In the early months of covid, the rollout of testing in the United States was catastrophically slow. Although the World Health Organization had validated a test and other groups had developed their own using basic molecular biology techniques, the CDC at first insisted on creating and relying on its own test. Adding to delays, the first version it shipped to state health labs didn’t work.

The FDA lagged, too. It didn’t authorize tests from diagnostic laboratories outside of the CDC until late February 2020.

On Feb. 27, 2020, Chu’s research lab detected covid in a teenager who didn’t meet the CDC’s narrow testing criteria. This case sounded an alarm that covid had spread below the radar. Scaling up to meet demand took time: Months passed before anyone who needed a covid test could get one.

Chu notes this isn’t 2020 — not by a long shot. Hospitals aren’t overflowing with bird flu patients. Also, the country has the tools to do much better this time around, she said, if there’s political will.

‘We Should Absolutely Get Prepared’

For starters, tests that detect the broad category of influenzas that H5N1 belongs to, called influenza A, are FDA-approved and ubiquitous. These are routinely run in the “flu season,” from November to February. An unusual number of positives from these garden-variety flu tests this spring and summer could alert researchers that something is awry.

Doctors, however, are unlikely to request influenza A tests for patients with respiratory symptoms outside of flu season, in part because health insurers may not cover them except in limited circumstances, said Alex Greninger, assistant director of the clinical virology laboratory at the University of Washington.

That’s a solvable problem, he added. At the peak of the covid pandemic, the government overcame billing issues by mandating that insurance companies cover tests, and set a lucrative price to make it worthwhile for manufacturers. “You ran into a testing booth on every other block in Manhattan because companies got $100 every time they stuck a swab in someone’s nose,” Greninger said.

Another obstacle is that the FDA has yet to allow companies to run their influenza A tests using eye swabs, although the CDC and public health labs are permitted to do so. Notably, the bird flu virus was detected only in an eye swab from one farmworker infected this year — and not in samples drawn from the nose or throat.

Overcoming such barriers is essential, Chu said, to ramp up influenza A testing in regions with livestock. “The biggest bang for the buck is making sure that these tests are routine at clinics that serve farmworker communities,” she said, and suggested pop-up testing at state fairs, too.

In the meantime, novel tests that detect the H5N1 virus, specifically, could be brought up to speed. The CDC’s current test isn’t very sensitive or simple to use, researchers said.

Stanford, the University of Washington, the Mayo Clinic, and other diagnostic laboratories that serve hospital systems have developed alternatives to detecting the virus circulating now. However, their reach is limited, and researchers stress a need to jump-start additional capacity for testing before a crisis is underway.

“How can we make sure that if this becomes a public health emergency we aren’t stuck in the early days of covid, where things couldn’t move quickly?” Pinsky said.

A recent rule that gives the FDA more oversight of lab-developed tests may bog down authorization. In a statement to KFF Health News, the FDA said that, for now, it may allow tests to proceed without a full approval process. The CDC did not respond to requests for comment.

But the American Clinical Laboratory Association has asked the FDA and the CDC for clarity on the new rule. “It’s slowing things down because it’s adding to the confusion about what is allowable,” said Susan Van Meter, president of the diagnostic laboratory trade group.

Labcorp, Quest Diagnostics, and other major testing companies are in the best position to manage a surge in testing demand because they can process hundreds per day, rather than dozens. But that would require adapting testing processes for their specialized equipment, a process that consumes time and money, said Matthew Binnicker, director of clinical virology at the Mayo Clinic.

“There’s only been a handful of H5N1 cases in humans the last few years,” he said, “so it’s hard for them to invest millions when we don’t know the future.”

The government could provide funding to underwrite its research, or commit to buying tests in bulk, much as Operation Warp Speed did to advance covid vaccine development.

“If we need to move to scale this, there would need to be an infusion of money,” said Kelly Wroblewski, director of infectious disease programs at the Association of Public Health Laboratories. Like an insurance policy, the upfront expense would be slight compared with the economic blow of another pandemic.

Other means of tracking the H5N1 virus are critical, too. Detecting antibodies against the bird flu in farmworkers would help reveal whether more people have been infected and recovered. And analyzing wastewater for the virus could indicate an uptick in infections in people, birds, or cattle.

As with all pandemic preparedness efforts, the difficulty lies in stressing the need to act before a crisis strikes, Greninger said.

“We should absolutely get prepared,” he said, “but until the government insures some of the risk here, it’s hard to make a move in that direction.”

KFF Health News is a national newsroom that produces in-depth journalism about health issues. 

Will Bird Flu Be the Next Pandemic?

By Amy Maxmen, KFF Health News

Headlines are flying after the Department of Agriculture confirmed that the H5N1 bird flu virus has infected dairy cows around the country. Tests have detected the virus among cattle in nine states, mainly in Texas and New Mexico, and most recently in Colorado, said Nirav Shah, principal deputy director at the Centers for Disease Control and Prevention, at a May 1 event held by the Council on Foreign Relations.

A menagerie of other animals have been infected by H5N1, and at least one person in Texas. But what scientists fear most is if the virus were to spread efficiently from person to person. That hasn’t happened and might not. Shah said the CDC considers the H5N1 outbreak “a low risk to the general public at this time.”

Viruses evolve and outbreaks can shift quickly. “As with any major outbreak, this is moving at the speed of a bullet train,” Shah said. “What we’ll be talking about is a snapshot of that fast-moving train.” What he means is that what’s known about the H5N1 bird flu today will undoubtedly change.

With that in mind, KFF Health News explains what you need to know now.

Q: Who gets the bird flu?

Mainly birds. Over the past few years, however, the H5N1 bird flu virus has increasingly jumped from birds into mammals around the world. The growing list of more than 50 species includes seals, goats, skunks, cats, and wild bush dogs at a zoo in the United Kingdom. At least 24,000 sea lions died in outbreaks of H5N1 bird flu in South America last year.

What makes the current outbreak in cattle unusual is that it’s spreading rapidly from cow to cow, whereas the other cases — except for the sea lion infections — appear limited. Researchers know this because genetic sequences of the H5N1 viruses drawn from cattle this year were nearly identical to one another.

The cattle outbreak is also concerning because the country has been caught off guard. Researchers examining the virus’s genomes suggest it originally spilled over from birds into cows late last year in Texas, and has since spread among many more cows than have been tested. “Our analyses show this has been circulating in cows for four months or so, under our noses,” said Michael Worobey, an evolutionary biologist at the University of Arizona in Tucson.

Q: Is this the start of the next pandemic?

Not yet. But it’s a thought worth considering because a bird flu pandemic would be a nightmare. More than half of people infected by older strains of H5N1 bird flu viruses from 2003 to 2016 died. Even if death rates turn out to be less severe for the H5N1 strain currently circulating in cattle, repercussions could involve loads of sick people and hospitals too overwhelmed to handle other medical emergencies.

Although at least one person has been infected with H5N1 this year, the virus can’t lead to a pandemic in its current state. To achieve that horrible status, a pathogen needs to sicken many people on multiple continents. And to do that, the H5N1 virus would need to infect a ton of people. That won’t happen through occasional spillovers of the virus from farm animals into people. Rather, the virus must acquire mutations for it to spread from person to person, like the seasonal flu, as a respiratory infection transmitted largely through the air as people cough, sneeze, and breathe. As we learned in the depths of covid-19, airborne viruses are hard to stop.

That hasn’t happened yet. However, H5N1 viruses now have plenty of chances to evolve as they replicate within thousands of cows. Like all viruses, they mutate as they replicate, and mutations that improve the virus’s survival are passed to the next generation. And because cows are mammals, the viruses could be getting better at thriving within cells that are closer to ours than birds’.

The evolution of a pandemic-ready bird flu virus could be aided by a sort of superpower possessed by many viruses. Namely, they sometimes swap their genes with other strains in a process called reassortment. In a study published in 2009, Worobey and other researchers traced the origin of the H1N1 “swine flu” pandemic to events in which different viruses causing the swine flu, bird flu, and human flu mixed and matched their genes within pigs that they were simultaneously infecting. Pigs need not be involved this time around, Worobey warned.

Q: Can I get sick from contaminated milk?

Cow’s milk, as well as powdered milk and infant formula, sold in stores is considered safe because the law requires all milk sold commercially to be pasteurized. That process of heating milk at high temperatures kills bacteria, viruses, and other teeny organisms. Tests have identified fragments of H5N1 viruses in milk from grocery stores but confirm that the virus bits are dead and, therefore, harmless.

Unpasteurized “raw” milk, however, has been shown to contain living H5N1 viruses, which is why the FDA and other health authorities strongly advise people not to drink it. Doing so could cause a person to become seriously ill or worse. But even then, a pandemic is unlikely to be sparked because the virus — in its current form — does not spread efficiently from person to person, as the seasonal flu does.

Q: What should be done?

A lot! Because of a lack of surveillance, the U.S. Department of Agriculture and other agencies have allowed the H5N1 bird flu to spread under the radar in cattle. To get a handle on the situation, the USDA recently ordered all lactating dairy cattle to be tested before farmers move them to other states, and the outcomes of the tests to be reported.

But just as restricting covid tests to international travelers in early 2020 allowed the coronavirus to spread undetected, testing only cows that move across state lines would miss plenty of cases.

Such limited testing won’t reveal how the virus is spreading among cattle — information desperately needed so farmers can stop it. A leading hypothesis is that viruses are being transferred from one cow to the next through the machines used to milk them.

To boost testing, Fred Gingrich, executive director of a nonprofit organization for farm veterinarians, the American Association of Bovine Practitioners, said the government should offer funds to cattle farmers who report cases so that they have an incentive to test. Barring that, he said, reporting just adds reputational damage atop financial loss.

“These outbreaks have a significant economic impact,” Gingrich said. “Farmers lose about 20% of their milk production in an outbreak because animals quit eating, produce less milk, and some of that milk is abnormal and then can’t be sold.”

The government has made the H5N1 tests free for farmers, Gingrich added, but they haven’t budgeted money for veterinarians who must sample the cows, transport samples, and file paperwork. “Tests are the least expensive part,” he said.

If testing on farms remains elusive, evolutionary virologists can still learn a lot by analyzing genomic sequences from H5N1 viruses sampled from cattle. The differences between sequences tell a story about where and when the current outbreak began, the path it travels, and whether the viruses are acquiring mutations that pose a threat to people. Yet this vital research has been hampered by the USDA’s slow and incomplete posting of genetic data, Worobey said.

The government should also help poultry farmers prevent H5N1 outbreaks since those kill many birds and pose a constant threat of spillover, said Maurice Pitesky, an avian disease specialist at the University of California-Davis.

Waterfowl like ducks and geese are the usual sources of outbreaks on poultry farms, and researchers can detect their proximity using remote sensing and other technologies. By zeroing in on zones of potential spillover, farmers can target their attention. That can mean routine surveillance to detect early signs of infections in poultry, using water cannons to shoo away migrating flocks, relocating farm animals, or temporarily ushering them into barns. “We should be spending on prevention,” Pitesky said.

Q: What could happen to people who get the H5N1 bird flu?

No one really knows. Only one person in Texas has been diagnosed with the disease this year, in April. This person worked closely with dairy cows, and had a mild case with an eye infection. The CDC found out about them because of its surveillance process. Clinics are supposed to alert state health departments when they diagnose farmworkers with the flu, using tests that detect influenza viruses, broadly. State health departments then confirm the test, and if it’s positive, they send a person’s sample to a CDC laboratory, where it is checked for the H5N1 virus, specifically. “Thus far we have received 23,” Shah said. “All but one of those was negative.”

State health department officials are also monitoring around 150 people, he said, who have spent time around cattle. They’re checking in with these farmworkers via phone calls, text messages, or in-person visits to see if they develop symptoms. And if that happens, they’ll be tested.

Another way to assess farmworkers would be to check their blood for antibodies against the H5N1 bird flu virus; a positive result would indicate they might have been unknowingly infected. But Shah said health officials are not yet doing this work.

“The fact that we’re four months in and haven’t done this isn’t a good sign,” Worobey said. “I’m not super worried about a pandemic at the moment, but we should start acting like we don’t want it to happen.”

KFF Health News is a national newsroom that produces in-depth journalism about health issues.