CDC Confirms Human Case of Bird Flu in Texas—What Does This Mean for Public Health?

A dairy worker in Texas has tested positive for avian influenza, the Centers for Disease Control and Prevention (CDC) confirmed Monday.

The announcement comes just a week after the United States Department of Agriculture (USDA) first announced avian flu outbreaks in certain dairy cow herds in Texas.

It’s uncommon for humans to catch the H5N1 subtype avian influenza—also known as H5N1 bird flu—and the CDC said this case is only the second one reported in the U.S. The first case was in Colorado in 2022.

The H5N1 bird flu is often found in wild bird populations, and sick birds can sometimes pass the virus to livestock or other mammals.

In this most recent case, the person in Texas likely became infected after coming in close contact with sick cattle, health officials said.

The case is relatively mild; the CDC said the patient has eye redness (conjunctivitis) but has no other symptoms. The person is being treated with an antiviral for flu, and is isolating.

“This infection does not change the H5N1 bird flu human health risk assessment for the U.S. general public, which CDC considers to be low,” the agency said in a press release. It acknowledged, however, that people who come into more frequent contact with possibly infected birds or other animals have a higher risk.

Since 2022, bird flu has been detected in wild, commercial, and hobbyist bird flocks—in total, over 82 million birds have been affected across 48 states and 512 counties. These outbreaks can cause issues for farmers—on Tuesday, Cal-Maine Foods, Inc., the country’s largest egg producer and distributor, culled nearly 2 million hens after an outbreak of avian flu at one of its facilities.

The USDA also found herds of dairy cows testing positive for bird flu in Kansas, Texas, Michigan, and New Mexico. It’s assuming a herd in Idaho will test positive, too.

“That worries me, because humans interact pretty closely with dairy cattle,” said Jill Foster, MD, professor of pediatric infectious diseases at the University of Minnesota Medical School. “You’ve got these dairy cows now that are infected, and people in the barn [are] pretty close with the dairy cows…I think that there’s probably going to be more spread to humans.”

Here’s what to know about bird flu, how it spreads between animals and humans, and what this infection means for public health.

What to Know About Bird Flu

This particular type of avian flu—H5N1—is one of many different subtypes of influenza A. It’s “still the same influenza that humans get,” but the naming refers to slight differences in proteins, Foster told Health.

Certain types of influenza A can lead to pandemics, such as the H1N1 “swine flu” in 2009 and the H1N1 “Spanish flu” in 1918 (which was later determined to be an “avian-like” virus.)

This is what infectious disease experts have feared happening since this H5N1 virus started causing outbreaks among wild birds and poultry in late 2021, Foster explained.

Luckily, however, this current strain of bird flu doesn’t seem to be mutating and making jumps into human populations in the same way as other problematic viruses, she said. 

“[The bird flu] seems to be something that just simmers and spreads quite easily. But it doesn’t seem to be one that changes a lot, the way that COVID [does],” said Foster. “Bird flu has been around for a couple of years, but has stayed mostly in the birds.”

Though it can spread easily between birds and other animals, the H5N1 flu virus does not seem to be very efficient at transmitting between animals and humans or from human to human, Foster added. Whereas increasing COVID infections provided more opportunities for the virus to mutate and better evade our immune systems, the same cannot be said for H5N1, at least for now.

In fact, limited spread between humans hasn’t been reported since 2007, and there’s no evidence that the bird flu could have sustained transmission in human populations.

However, when people do get sick with bird flu, it can be a cause for concern. Some people are asymptomatic or have mild infections, where they’ll experience conjunctivitis or flu-like upper respiratory symptoms. But others will have more serious cases that can lead to pneumonia, fever, body aches, shortness of breath, and in very rare cases, diarrhea, nausea, or seizures.

Since 2021, hospitalizations linked to various strains of bird flu have been reported in China and Cambodia, and China has reported over a dozen deaths.

People who get sick with bird flu can be treated with the antiviral Tamiflu (oseltamivir), which works against influenza A.

How Might Bird Flu Affect Your Health?

Because the risk to the general public in connection with this confirmed bird flu case is low, the average person doesn’t need to be too worried about contracting the H5N1 virus.

“Human infection based on close occupational exposure to a sick animal is of course important to know about, but is also very different than the case of human-to-human transmission, which would be a concern for public health,” Sarah Hamer, PhD, DVM, director of the Schubot Center for Avian Health and professor of epidemiology at the Texas A&M University School of Veterinary Medicine and Biomedical Sciences, told Health.

However, those who may be coming into contact with sick poultry or dairy cows could be seeing a higher risk. “As soon as you start getting cases, you’re going to have more spread,” Foster said.

Because of this, the CDC recommends anyone who could be coming into contact with ill or dead animals use proper personal protective equipment (PPE), including vented safety goggles, disposable gloves, boots, masks, disposable coveralls, and a head covering.

“PPE is a big one. And then it’s just re-emphasizing things like proper hand hygiene, washing your hands frequently, if you’re not feeling well, staying home,” said Mike Kleinhenz, DVM, PhD, clinical associate professor of dairy cattle production at Texas A&M University School of Veterinary Medicine and Biomedical Sciences. “Just reinforcing some of those good hygiene practices is important for dairy farmers to do—for their employees and for themselves.”

As for where the average person comes into contact with dairy—the grocery store—there’s also little cause for concern.

There’s no risk of people accidentally getting bird flu from consuming cow’s milk or other dairy products, so long as it’s pasteurized, the Food and Drug Administration (FDA) said. That process is able to effectively kill viruses such as influenza.

And though transmission among cows is something experts are monitoring, for now, there’s no evidence that bird flu could lead to any major disruptions in the U.S. dairy market, Kleinhenz told Health.

“From what we’re seeing on farms that are affected by this, [it’s] a small percentage of the cows that are actually becoming infected, and having to have their milk diverted from the saleable pool,” he said. “For the overall milk supply, we don’t expect to have shortages.”