How Concerned Should We Be About Avian Flu Cases in Cattle, Poultry?

Danielle Nierenberg

Danielle Nierenberg

I’m always happiest when I can discuss stories of scientific advances and food system research success—what’s going well in the world. 

But at the same time, there’s so much we don’t understand.

To me, a particularly scary reminder of our vulnerability is contagious disease pathogens, like viruses. Right now, we’re seeing a panzootic—the animal equivalent of a pandemic—of bird flu cases. The strain is formally called Highly Pathogenic Avian Influenza A H5N1, or just H5N1, and in just the past 30 days, the U.S. Department of Agriculture has recorded 8.8 million cases of H5N1 in poultry.

More concerning, a multi-state outbreak of H5N1 bird flu in dairy cows was reported in March 2024—the first time these viruses have been found in cattle. The virus strain has now been found in 34 herds of cattle in 9 states across the United States, and a goat in Minnesota tested positive for the disease in March. 

Spikes in H5N1 among poultry flocks and dairy herds have particularly concerning food system implications, and raise the risk that humans could become infected—making prevention and containment urgent.

“Any time a pathogen like H5N1 shifts from one species suggests that it is evolving,” Dr. Barbara Kowalcyk, Director of the Food Policy Institute at George Washington University, tells Food Tank. “The primary concern is that it will evolve into a pathogen that can cause illness in humans.”

The U.S. Centers for Disease Control and Prevention (CDC) states the public health risk from H5N1 is currently low, Dr. Kowalcyk says, “but the situation needs to be monitored closely.”

There are lots of questions right now around what H5N1 means for our communities and for the global food system. Let’s clear them up with answers from Food Tank’s research team.

Q: What about people? Can humans catch H5N1?

A: Yes—it’s rare, but extremely serious. Only 888 cases of H5N1 in humans were reported worldwide from January 2023 to March 2024, but the fatality rate is roughly 50 percent.

(For context, during the first three years of the Covid-19 pandemic in the U.S., approximately 1.03 million cases were reported; the fatality rate was approximately 1.1 percent, per Johns Hopkins University.)

Nearly all the human cases of H5N1 in recent years were associated with lengthy contact with infected birds or with their saliva, mucus, or feces without proper safety measures like gloves and respiratory or eye protection.

But in April 2024, a human case of H5N1 was identified in a farmworker in Texas who was believed to have contracted the disease from dairy cattle. The farmworker recovered, but the World Health Organization believes this to be the first-ever instance worldwide of a human case of H5N1 contracted from a mammal, rather than from poultry.

Q: Can people spread H5N1 to other people?

A: We don’t know for sure. So far, there has been no known human-to-human spread of the current H5N1 virus, according to the U.S. Centers for Disease Control and Prevention. 

Here’s the thing: As we saw with the spread of Covid-19, viruses are able to mutate and adapt to their environments. Cases of H5N1 showing up in mammals—and spreading from mammals to humans—is a concerning development.

Unlike Covid-19, H5N1 does not currently appear to be a respiratory disease, said Jared Taylor, a professor of veterinary pathobiology at Oklahoma State University. Current cases have been transferred through fluids or direct contact, rather than through the air, which makes the disease easier to contain.

“The concern is, if it becomes effective as a respiratory pathogen in cattle, it’s more likely to become effective as a respiratory pathogen in humans,” Taylor said.

Q: Are beef, dairy, and eggs safe to consume? 

A: Long story short, yes. 

Current results from tests by the U.S. Food and Drug Administration show that pasteurization effectively inactivates the virus. The FDA reiterated its longstanding guidance that people avoid consuming raw milk.

About 1 in 5 samples of pasteurized milk from commercial retailers contained remnants of the virus, but virologists and food scientists are confident that this is merely a sign that the virus may have been widespread on the farm—not that it’s currently dangerous in the milk. No live, active virus was detected in any milk samples the FDA analyzed in its most recent round of testing.

For beef, the U.S. Department of Agriculture began collecting retail samples of ground beef for testing this week, but scientists believe there is also no current threat of any kind to the safety of meat.

It also seems like eggs are safe. It’s unlikely that eggs from infected chickens would make it to retail in the first place, the FDA says, and there’s no evidence that the virus would be transmitted to humans from well-cooked eggs. However, the agency is continuing to test.

“There have been no cases of any human being contracting bird flu or H5N1 from meat or milk,” says Scott Haskell, a Professor of Food Safety at the Institute for Food Laws and Regulations at Michigan State University.

Q: What protections are currently in place to keep us safe from H5N1? What more can we do?

A: As we learn more about the current strain of avian flu, stronger policy protections and scientific barriers are being developed. 

Many current efforts are focusing on containment. In the U.S. last week, for example, government officials began requiring that lactating dairy cows test negative for bird flu before crossing state lines, and all labs and veterinarians nationwide must report positive tests. We can't ignore the impact of industrial poultry production on bird flu cases, and we need to make sure corporations take meaningful action beyond only "de-populating" infected flocks.

And if you work with poultry or livestock—as a farmer, veterinarian, animal health responder, slaughterhouse worker, or own backyard chickens—please be sure to avoid direct contact with sick animals or surfaces the animals have touched, and clean your hands and surfaces regularly.

Looking forward, we need a One Health initiative, experts say. This means that medical professionals, veterinarians, ecologists, farmers, and other researchers across disciplines need to be in close collaboration, and they need to consider how people, animals, plants, and the environment all intersect.

"The key to protecting human and animal health is containing the spread of the virus within cattle through a One Health approach,” Dr. Kowalcyk tells Food Tank. “Managing the spread of H5N1 requires increased surveillance to gain a better understanding of the scope of the spread of the virus and identify potential points for intervention.”

What other questions do you have about H5N1? We’re stronger when we’re armed with all the facts—we can make more effective decisions and push for more meaningful change. So share what’s on your mind by emailing me at danielle@foodtank.com, and we’ll continue to keep a close watch and share updates with Food Tankers.

(Danielle Nierenberg is the President of Food Tank and can be reached at danielle@foodtank.com)