As Bird Flu Spreads, Feds Might Undercut States by Firing Scientists, Removing Data

Michael Crusan, a spokesperson for the Minnesota Board of Animal Health, compared state-federal bird flu cooperation to a dance.

“You can’t swing dance without a partner,” Crusan said. “So how are we supposed to keep this process running smoothly?”

70 Human Cases
The highly pathogenic avian influenza virus, known as H5N1, has killed millions of wild birds and has led to emergency culling of commercial flocks.

Nationwide, there have been 70 confirmed human cases since 2024, according to the CDC. Most of these cases have been among farmworkers, who are in daily close contact with poultry and cattle.

California has tracked the most cases, with 38 patients, nearly all exposed to the virus from dairy herds, followed by Washington state with 11 cases. Other infections in humans have been confirmed in Colorado, Iowa, Louisiana, Michigan, Missouri, Nevada, Oregon, Texas and Wisconsin.

In recent weeks, Ohio and Wyoming reported their first human cases of the virus. A CDC study found cases among three dairy veterinarians, with one working in a state that had no infected cattle.

In January, a patient in Louisiana died after contracting the virus, the first human death from bird flu. The patient was an older adult with underlying medical conditions, and had contracted the virus after exposure to a backyard flock and wild birds.

Hospitalization remains rare. For now, bird flu doesn’t easily infect humans and doesn’t spread from person to person, health experts say. The CDC says there is little risk to the general public, but that could change as the virus mutates and continues to infect mammals such as cattle. The virus also has been found in domestic cats.

To eradicate bird flu, experts are emphasizing comprehensive case surveillance, testing and an overall public health strategy that recognizes the interdependence of humans, animals and the environment.

“You can’t have healthy humans without healthy animals, wild and domestic, and healthy environments,” said Maurice Pitesky, a food security expert at the University of California, Davis School of Veterinary Medicine. “Ultimately, you’re trying to reduce the potential of the virus to move from those wild waterfowl to those farm animals.”

Dr. Amesh Adalja, an infectious disease physician and scholar at the Johns Hopkins Center for Health Security, said the pressure is mounting to safeguard farms.

“The longer this virus circulates on farms, especially infecting dairy cattle and exposing humans that work on those farms, the more chances it has to evolve to something that is more dangerous for humans,” Adalja said.

The virus has been detected in more than 200 mostly wild and feral mammals in the U.S. since 2022. Those mammals may have become infected from eating fresh wild bird carcasses, but there is no indication of transmission from mammal to mammal, experts say.

A recent CDC study found cases in two indoor cats belonging to dairy farmworkers. Other infections in cats have been linked to raw pet food. Officials are urging people to refrain from drinking raw milk and from feeding dogs and cats raw pet food.

“The more mammals it infects,” Adalja said, “the more chances it has to adapt to mammals.”

All 50 States
More than 166 million birds across all 50 states have been infected nationwide since 2022, according to CDC data as of Tuesday. Over the past month, the virus has been detected in 86 commercial flocks and 51 backyard flocks. Infected poultry flocks must be culled when an outbreak occurs. In groceries nationwide, egg prices have surged amid the shortages.

The virus is also suspected in recent die-offs of wild birds. In five Michigan counties as of mid-February, more than 300 dead wild birds, including geese and mallard ducks, have been found, the state Department of Natural Resources reported. The department has issued guidance on how waterfowl hunters and property owners can stay safe when encountering dead birds.

Melinda Cosgrove, laboratory scientist manager at the department’s Wildlife Health Section, said her state’s confirmed positive cases are mostly in poultry flocks. To stay abreast of potential cases in the wild, the state has an “Eyes in the Field” webpage by which residents can report sick or dead wildlife to help the department track potential cases.

Those migratory birds are behind the spread across farms, said Kevin Snekvik, executive director of the Washington Animal Disease Diagnostic Laboratory. “Birds migrating north and south up to Alaska, they’re the culprits,” said Snekvik, who is also a professor at Washington State University’s Department of Veterinary Microbiology and Pathology.

States have also been monitoring changes in bird flu patterns by tracking the virus in wastewater. The U.S. has long avoided vaccination of poultry because many of its trading partners will not import vaccinated birds. But federal officials earlier this month gave conditional approval of an updated version of a previous vaccine to protect poultry against the H5N1 virus.

Farmworker Testing
In Nevada, a recent spillover to dairy cattle of a specific H5N1 genotype previously found in birds was detected in a milk sample, officials announced earlier this month.

Seventeen states have reported outbreaks in dairy cows. Cows usually recover from the virus, but cattle must be isolated when the virus is detected to prevent further spread. It can be spread to humans through close contact.

Despite the widespread cases in dairy farms, not all states have joined a federal-state partnership to test milk. Currently, 36 states test under the surveillance strategy.

Helping dairy and poultry farmworkers get tested is important for public health response. But many farmworkers are immigrants with no sick leave and who may speak primarily Indigenous languages or Spanish. The Trump administration’s deportation efforts have caused further reticence to report symptoms, said Laura-Anne Minkoff-Zern, a food systems scholar and human geographer at Syracuse University who studies agricultural labor.

“You have a population of workers who don’t have access to health care to begin with,” she said, noting how many dairy farm laborers live in rural or remote places far from city centers. “You have this geographical barrier. You have a linguistic barrier. You have a cultural barrier. And then, of course, today, you have on top of it a lot of fear.”

Since dairy cattle infections were first detected in California in September 2024, the state’s Animal Health and Safety Lab, the only lab in the state handling the most dangerous samples, has received between 400 and 2,000 samples weekly, lab director Ashley Hill wrote in an email to Stateline.

The lab currently has just five technicians authorized to do most of the testing and a handful of support staff who can chip in. Lab technicians are set to strike this week along with university health care, research and technical professionals across the state, according to the union, which represents 20,000 workers.

Nada Hassanein is a health care reporter for Stateline with a focus on inequities. The article originally appeared in Stateline.