Science
Killing 166 million birds hasn’t helped poultry farmers stop H5N1. Is there a better way?
When the deadly H5N1 bird flu virus made its first appearance at a U.S. poultry farm in February 2022, roughly 29,000 turkeys at an Indiana facility were sacrificed in an attempt to avert a larger outbreak.
It didn’t work. Three years later, highly pathogenic avian influenza has spread to all 50 states. The number of commercial birds that have died or been killed exceeds 166 million and the price of eggs is at an all-time high.
Poultry producers, infectious disease experts and government officials now concede that H5N1 is likely here to stay. That recognition is prompting some of them to question whether the long-standing practice of culling every single bird on an infected farm is sustainable over the long-term.
Instead, they are discussing such strategies as targeted depopulation, vaccinations, and even the relocation of wetlands and bodies of water to lure virus-carrying wild birds away from poultry farms.
But each of these alternatives entails a variety of logistical, economic and environmental costs that may eclipse the intended savings.
“People talk about common-sense solutions to bird flu,” said Dr. Maurice Pitesky, a veterinarian and commercial poultry expert at UC Davis. “But that’s what mass culling is. There’s a reason we’ve been doing it: It’s common sense.”
The current version of the bird flu — known as H5N1 2.3.4.4b — is both highly contagious and highly lethal. It has has plowed through the nation’s commercial chickens, turkeys and ducks with a mortality rate of nearly 100%.
“There’s a reason why they call it ‘highly pathogenic avian influenza,’” said Angela Rasmussen, a virologist at the University of Saskatchewan’s Vaccine and Infectious Disease Research Organization. “It just goes straight through a flock like a hot knife through butter.”
And it’s why most researchers and veterinarians promote mass culling, describing it as humane and cost-effective.
A natural death from H5N1 is not pleasant for a chicken, said Rasmussen. The virus produces a gastrointestinal infection, so the birds wind up dying of diarrhea along with respiratory distress.
“It’s like Ebola without the hemorrhage,” she said.
Sparing birds that don’t look sick is a gamble. They may be infected and able to spread the virus through their poop before they have any outward signs of illness. The only way to know for sure is to test each bird individually — an expensive and time-consuming prospect. And if even a single infected bird is missed, it can spread the virus to an entire flock of replacements, Rasmussen said.
Besides, she said, all of the extra work that would go into making sure some chickens can stay alive would only drive up labor costs and ultimately make eggs more expensive.
It also has the potential to increase the total amount of virus on farms, which is dangerous for human poultry workers, said Dr. Ashish Jha, dean of the Brown University School of Public Health.
“One of the reasons to cull early is that you don’t want a lot of bird-human exposures,” he said. “The more infections we introduce to humans, the more mutations we’re going to see that increase the risk for a broader epidemic or pandemic.”
For all of these reasons, international trade agreements require mass culling — also known as “stamping out” — so that importers don’t get a side of H5N1 with their poultry, said Dr. Carol Cardona, a veterinarian and avian influenza researcher at the University of Minnesota.
That’s not the only financial incentive for mass culling. The USDA reimburses farmers for eggs and birds that have to be killed to contain an outbreak, but not for birds that die of the flu.
Yet at times, this has meant killing more than 4.2 million birds, most of which may have been healthy.
Bill Mattos, president of the California Poultry Federation, said a more targeted approach could be feasible when all birds are not living under the same roof. In California, for instance, farms that raise broiler chickens typically operate multiple stand-alone buildings with separate ventilation systems, entryways and exits.
Biosecurity measures like these can keep pathogens from spreading between barns, Cardona said. Risks could be reduced further by requiring workers to change their clothes and boots when moving from barn to barn, or by assigning workers to a single barn, she said.
But others, including Dr. John Korslund, a veterinarian and former USDA researcher, are skeptical that such a practice could work, considering the virulence of H5N1.
“Chickens are infected and shedding virus very early, before evidence of clinical illness,” Korslund said. “Odds are that ‘healthy’ buildings on infected premises are in reality in the early stages of incubating infections,” he said.
While it was possible some buildings might remain virus free, and some birds could be salvaged, the downsides of this approach are huge, Korsland said. “A lot of additional virus will be put into the environment,” he said.
Indeed, flu particles from one facility can escape exhaust fans and travel great distances, said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota. Studies have shown that “the movement of virus from farm to farm was associated with wind direction and speed,” he said.
Bird flu vaccines may offer some protection. Both China and France use them, and the USDA granted a conditional license this month for an H5N2 vaccine designed for chickens, according to Zoetis, the company that developed it.
While some are heralding vaccines as a potential tool to inoculate the nation’s poultry farms, others say the costs could be too much.
Most U.S. trade partners are not keen to import poultry products from countries that vaccinate their birds due to concerns that the shots can mask the presence of the virus. And most will blackball a nation’s entire poultry portfolio, even if just one region or type of poultry is infected.
The U.S. exports more than 6.7 billion pounds of chicken meat each year, second only to Brazil, according to the National Chicken Council. So as long as foreign buyers are resistant to vaccination, the shots probably won’t be deployed even if egg-laying hens are getting wiped out by the virus.
As members of the U.S. Congressional and Senate Chicken Caucuses wrote in a letter this month to the USDA, “if an egg-laying hen in Michigan is vaccinated for HPAI, the U.S. right now would likely be unable to export an unvaccinated broiler chicken from Mississippi.”
The new H5N2 vaccine might allay such concerns. While it would offer protection against H5N1, it would elicit antibodies that look distinct from the ones that arise from an actual infection, Cardona said.
Pitesky said that none of these measures will work if we don’t do a better job with flu surveillance and farm placement.
Wildlife and agriculture officials should ramp up their testing of wild birds to determine where the virus is moving and how it is evolving, he said. That will require global coordination because infected birds can travel back and forth between the U.S., Canada, Russia, East Asia and Europe.
Poultry farms near ponds, lagoons or wetlands that attract wild birds should be on high alert during migration season, Pitesky said. Farmers should use apps such as eBird, BirdCast or the Waterfowl Alert Network to keep tabs on when the birds are nearby so they can step up their biosecurity measures as needed, he said.
It may be possible to lure wild birds away from agricultural facilities by bolstering wetlands in more remote areas, he said.
“I keep pushing the idea of starting to reflood some of those wetlands, but we haven’t done it in any kind of strategic fashion,” Pitesky said.
The idea makes sense, but has been brushed off as “pie in the sky, which I push back on,” he said. “I’m like, what we’re doing right now is obviously not working.”
Science
Contributor: The crucial medical question that AI can’t ever answer
One of us got a call last spring from a longtime friend. The story was familiar: two doctors, an MRI, an online AI tool, a stack of articles — and one anxious question. “Everything tells me something different. The AI says I might need surgery. What should I do?”
We believe there’s one key response to anyone in this all-too-common conundrum: “What matters most to you?”
There was a long pause.
That pause is one of the most important moments in modern healthcare — and it is exactly the question artificial intelligence is unable to address.
In our careers as physicians and researchers, we have found, clearly and repeatedly, that for many common conditions the medical evidence does not point to a single “right” answer. The biology is often close. What determines the success of an outcome is whether the choice fits the person making it.
Some patients with back pain want the fastest possible return to physically demanding work, even if it means surgery. Others want to avoid an operation at almost any cost, even if recovery takes longer. The scan may look the same. The lives behind the scan are not.
That insight is becoming critically important as artificial intelligence moves deeper into everyday health decisions.
In our research on AI and clinical decision-making, we’ve studied what happens when systems are trained to optimize medical outcomes but are blind to human values. In plain English, today’s AI is very good at telling you what usually works for people like you with similar demographics and medical histories. It is far less capable of understanding what you are trying to protect, avoid or prioritize.
This matters because some of the most common and most expensive medical decisions are not purely biological. Should someone with low-risk prostate cancer choose surgery, radiation or careful monitoring? Should a person with atrial fibrillation undergo a procedure or manage the condition with medication? Should a patient with chronic knee or back pain operate now or try months of physical therapy to see whether surgery can be avoided?
In these situations, the medical differences between options are often small or uncertain. What makes the biggest difference is whether the treatment aligns with the patient’s goals: tolerance for risk, willingness to undergo recovery, ability to adhere to long-term therapy or simply what kind of life they want to live.
AI systems can calculate probabilities. They cannot determine what those probabilities mean to a particular person.
In some respects, artificial intelligence may know more medicine than any individual physician. It can synthesize millions of scientific papers, clinical studies and patient records in seconds. Yet it knows remarkably little about the person sitting across from it. AI does not know a patient’s goals, fears, obligations, tolerance for risk or personal definition of a good outcome. And because it knows little about either the patient or the physician, it knows even less about the conversation between them — the place where facts, values and trust come together to produce the right decision for a particular person.
A second patient story brought this home. A retired teacher was referred after an AI-based symptom checker flagged a heart rhythm abnormality and “favored” an invasive procedure. The patient arrived frightened, convinced there was one correct path. When we talked, it became clear that what mattered most was avoiding a long recovery and staying healthy enough to travel to see grandchildren.
Medication and monitoring — less dramatic, but well-supported by evidence — fit those goals better. The AI wasn’t wrong. It just didn’t know what mattered.
This blind spot is not trivial. Roughly a quarter of U.S. healthcare spending flows through decisions in which patient preferences meaningfully affect outcomes. When those preferences are ignored — by people or by algorithms — care becomes misaligned. That can mean unnecessary procedures, poor adherence, regret and rising costs without better health.
So what should consumers do when an app, portal or “smart” tool recommends a course of action?
Start with three questions.
First: “Best for whom?” If a tool says one option is best, ask whether it means best on average — or best for someone with your priorities.
Second: “What does this system not know about me?”
AI can see lab values and imaging results. It cannot see your job, your family responsibilities, your fears or what you are trying to get back to.
Third: “What happens if I wait or choose differently?”
Many important medical decisions are not emergencies. When options are close, taking time to reflect is often part of good care.
Artificial intelligence is becoming a powerful partner in medicine. It can help explain options, surface evidence and reduce confusion. But it should inform human decisions, not replace them.
AI may know more medicine than any physician.
It knows far less about any patient.
And it knows least about the conversation between them.
The most important variable in your healthcare is not in any algorithm. It is you.
James N. Weinstein is a surgeon and former chief executive of Dartmouth Health. He is a clinical professor at Northwestern University’s Kellogg School of Management and global head of Health Futures at Microsoft, which develops AI systems. Ogan Gurel is a physician and assistant professor at the University of Texas at Arlington, where he researches AI, causal inference and patient decision-making.
Science
Fans slam FIFA’s cooling breaks. Why the U.S. World Cup team doctor disagrees
While it may not be remembered as FIFA’s most controversial decision of the 2026 World Cup, the institution of mandatory cooling breaks in all matches has been met with boos and derision, with critics saying the pauses disrupt the game’s flow and offer little benefit in air-conditioned environments.
“They’re in a dome here! Temperature-controlled, climate-controlled — why are we having a break?” fumed one England fan to a radio reporter outside the England-Croatia match in Arlington, Texas, where field temperatures inside AT&T Stadium approached a comfortable 70 degrees Fahrenheit despite an outdoor heat and humidity index near 105 degrees.
But for Dr. Bert Mandelbaum, chief medical officer for U.S. men’s soccer and vice chair of Cedars-Sinai Medical Center’s orthopedic surgery department, the breaks set an important precedent for prioritizing athlete health in extreme heat, even at the highest levels of competition.
“I do think the cooling breaks are an important part of the game. I’m really excited and happy that we are employing those,” he said by phone Tuesday morning, hours after the U.S. team’s 4-1 knockout loss to Belgium.
“Difficult weather environments bring on dehydration and can create severe exhaustion, heat exhaustion, and those [conditions] have tremendous and dire consequences,” Mandelbaum said. “Talk radio could discuss it over and over again, but from our standpoint, the real messaging should be to our communities, our club players, that this is an important part of our game, and the cooling break is how we help manage it.”
Warming climate conditions are forcing changes to human behavior all around the globe, including on the pitch.
Extreme heat kills more people each year than all other forms of extreme weather combined. Elite athletes are not immune to its effects.
As temperatures during a game rise, the circulatory system diverts blood to the skin to lower core body temperatures at the same time that active muscles require oxygen-rich blood. This places extra strain on the heart, which pumps harder to keep up with demand. Sweating players lose electrolytes faster than they can consume them, leading to muscle cramps, fatigue and dizziness.
Virtually all aspects of the game degrade in the heat, Mandelbaum said. Players’ performance, recovery ability and decision making erode. Artificial turf becomes intolerably hot, and the soil in natural grass can harden until it’s like playing on concrete. Air molecules inside the ball expand, making it a harder and faster object. Even fans risk injury: 22 people were treated for heat-related illnesses at a FIFA Fan Festival in Houston last month.
Mandelbaum directs the FIFA Medical Center of Excellence at Cedars-Sinai and was part of the FIFA Medical Committee in 2014, when the first World Cup cooling break was called during a Netherlands-Mexico match in Fortaleza, Brazil.
At the time, the sport’s governing body recommended hydration breaks if temperatures surpassed 102.2 degrees.
This year’s World Cup, hosted across the U.S., Canada and Mexico, is the hottest played since the tournament began in 1930. It has coincided with a withering heat wave in the eastern U.S. With a heat index of nearly 104 degrees at kickoff, the July 4 match in Philadelphia between France and Paraguay is believed to be the second-hottest game in World Cup history, after a 105-degree match in 1994 between Ireland and Mexico in Orlando, according to meteorologist Brad Maushart.
FIFA announced in December that this year’s tournament would be the first in which all matches must pause once in each half for hydration and cooling, regardless of temperature conditions.
FIFA President Gianni Infantino said mandatory breaks equalize playing conditions in all matches. When they haven’t been loudly booing, many fans have noticed that teams often appear to spend as much time strategizing during the pauses as they do hydrating.
Given this, “if we were to use hydration breaks only in those matches where it was too hot and not in the other matches, we would give an advantage or a disadvantage to some of the coaches or some of the teams,” Infantino told Sports News Television.
Harry Brown, a postdoctoral research associate at the University of Sydney’s Heat and Health Research Centre, expressed frustration over the universal breaks in an op-ed in the journal Nature.
“Although it might seem fair to treat all games in the same way, this blanket approach risks undermining trust in heat-safety measures. If breaks are always used, regardless of risk, they stop being meaningful and start looking like routine stoppages,” Brown wrote.
Without active efforts to lower players’ core temperatures, pausing game play may not be enough to effectively stave off heat injury, he wrote. In his own research, Brown’s team compared the effects of passive breaks against breaks with active cooling measures on the health of players participating in 90-minute soccer games in 104-degree heat and 41% humidity.
When players cooled themselves with cold drinks and icy towels during short breaks and took longer halftimes, their core temperatures and cardiovascular strain lowered considerably more than they did after only passive breaks, Brown wrote.
Other physicians argued that even an under-utilized break was better for athletes than nothing at all.
“I would say that it’s better to err on the side of having cooling breaks rather than risk not having them,” said Dr. Miho J. Tanaka, an associate professor of orthopedic surgery at Harvard Medical School who also serves as a team physician for the Boston Red Sox and the New England Revolution.
“Ultimately, an individualized screening or monitoring process may be the safest approach, but we are still far from being able to precisely identify and intervene when an individual player may be at risk,” she said. “Until we are able to do so, having standardized breaks is a step in the right direction, as long as teams and players are informed when to escalate their level of concern and take action when more aggressive measures are truly needed.”
While a cooling break is rarely medically necessary inside a climate-controlled indoor stadium, Mandelbaum said it still sends a valuable message to players around the world: If hydration breaks are a part of the sport’s biggest event, they should be allowed at every other level of play.
“Not only is [the hydration break] a good thing, it’s a necessary thing,” Mandelbaum said. “This is the world’s game … we have to figure out how to help players at all levels and ages to have the ability to thermoregulate, hydrate, how to do it well.”
Science
New FireSat satellites promise faster wildfire detection over California and beyond
A trio of satellites set to launch early Tuesday will give wildland firefighters more time to respond and scientists more information about fire-prone regions across the globe.
The launch from Vandenberg Space Force Base is the first phase in a constellation called FireSat that will eventually cover the globe with 50 satellites collecting high-resolution imagery of fires and conditions on the ground every 20 minutes.
Earth Fire Alliance, the nonprofit group behind FireSat, got the project off the ground with $69 million in grants from the Bezos Earth Fund, Google and the Gordon and Betty Moore Foundation.
San José-based Muon Space built the satellites. Muon and the California Department of Forestry and Fire Protection are both FireSat partners.
The satellites use advanced thermal sensors to detect heat and can pick up signals from fires as small as a beach bonfire, as well as cooler fires that have been smoldering for days, according to Michael Falkowski, lead scientist at Earth Fire Alliance. That information will help fire officials, including the Los Angeles and Los Angeles County fire departments, understand whether blazes are growing, where they are headed and how much soot and smoke they are generating.
FireSat’s infrared instruments detected this small roadside fire in Medford, Ore., during a 2025 test flight.
(Muon Space)
“If we can differentiate between a smoldering fire and a flaming combustion fire, it really has a big impact on how we can understand the air quality emissions coming off the fire,” Falkowski said.
Fires that burn at low temperature produce more harmful gases than hot fires. Think about a campfire. When it’s burning hot with bright flames, there is relatively little smoke. When it’s smoldering, it produces lots of thick, white or gray smoke.
Wildfires work the same way.
A hot, fast-burning fire has enough oxygen and heat to burn with more complete combustion, producing less smoke for every pound of wood burned.
Earth Fire Alliance will provide data from these first three satellites in the next few months to Cal Fire and fire agencies in Oregon, Texas, Australia and Portugal. Cal Fire will share it with Southern California fire agencies.
The network will also turn its sensors on in the Amazon Basin for the Brazilian nonprofit Amazon Environmental Research Institute.
Cal Fire should begin receiving data from the scientists later this year, according to Falkowski, who joined Earth Fire Alliance last year from NASA, where he was an earth science program manager running the agency’s fire science program.
Instruments on the satellites will be able to detect fires the size of a shipping container, and distinguish between hot, intense wildfires and cooler, smoldering ones.
(Muon Space)
Falkowski said the new FireSat satellites are a big improvement over existing ones because they will be able to see smaller fires with better resolution and distinguish low-intensity “cool” fires from high-intensity hot ones.
“The satellites are really designed to measure fire across the entire temperature profile, so we can see cool fires all the way up to really hot fires,” he said.
That kind of granular information is important for emergency responders in the field and planners who make decisions about calling for extra help or ordering evacuations.
The National Oceanic and Atmospheric Administration operates three satellites that can detect a fire somewhere inside a square 1,230 feet across.
In contrast, instruments on the FireSat satellites will be able to detect small brush and roadside fires 16 feet across.
Cal Fire officials have long embraced new technology to get ahead of wildfires in recent years, testing autonomous firefighting helicopters and partnering with UC San Diego to use artificial intelligence to filter images from a network of more than 1,200 cameras on lookout towers and mountain tops. The Alert California program is able to spot smoke in a video and sends automated messages to one of 21 agency command centers across California.
In 2025, Alert California sent out automated warnings before authorities even received 911 calls from the public 51% of the time, according to Phillip SeLegue, staff chief of Cal Fire’s intelligence program.
A worker at Mountain View-based Muon Space puts the final touches on a wildfire-detection satellite scheduled to launch Tuesday on a SpaceX rocket. The satellites will be tracking fires across the globe.
(Muon Space)
FireSat will help incident commanders get better information more quickly, and, unlike fire-spotting aircraft, the satellites can linger over a fire for days or weeks and aren’t hampered by high winds or smoke.
Travis Medema, chief deputy for the Oregon State Fire Marshall, said his office will use FireSat to plan escape routes and monitor fires. “If we can fight these when they are small, we feel we will be more efficient and can protect Oregonians,” he said.
One expert noted that turning satellite data into information useful to firefighters and forestry managers will take some time. The FireSat data will “be amazing for fire nerds, but how and whether it helps individual fires remains to be seen,” said Joe H. Scott, founder of Pyrologix, a wildfire analysis firm based in Missoula, Mont. “Right now, we are not basing decisions on where satellites tell us a fire is,” Scott said.
Pyrologix develops wildfire risk management models for federal agencies, local governments and utilities. Scott said FireSat’s high-resolution data will help him build better prediction models that take into account weather, drought, plants and the history of fires in a region.
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