Avian Influenza FAQ: What You Need to Know About Bird Flu

The virus—known as H5N1—is an influenza virus. It’s different from the seasonal influenza viruses that circulate each winter, which primarily sicken people. H5N1 is one of many influenza viruses that typically spread among other species, particularly birds, according to William Schaffner, MD, an infectious diseases specialist at Vanderbilt University Medical Center in Nashville, Tennessee. 

Many of these other flu viruses don’t affect us, Schaffner says. But the H5N1 bird flu virus, which was first identified in 1996 when it spread from wild birds to domestic birds, can. In fact, it’s considered a highly pathogenic avian influenza, because it can cause severe disease in birds and in other species. In a 1997 outbreak, H5N1 infected more than 860 people in Southern China and Hong Kong. More than half of them died from the virus.

Many wild birds may harbor the virus but show no signs of sickness. When these birds stop during migration near other birds for food or water, they can spread the bird flu. A lot of domestic or farm birds like chickens die within days of infection, Schaffner says.

According to the CDC, people can catch the bird flu if the virus gets into their eyes, nose, or mouth, or is inhaled. So far, there have been 67 confirmed bird flu infections in people in the U.S. In most cases, the people who got sick are agricultural workers; many work with dairy cows, Schaffner says. Some infections might have occurred when a worker touched a sick or dead cow or raw milk contaminated with the virus and then their own eyes, nose, or mouth; or by liquid containing live virus splashing on a worker. In three of the U.S. cases, it’s unclear how the sick people were exposed to the virus. 

One person, in Louisiana, died from the virus, an older man who had chronic health conditions, Schaffner says. He may have inhaled H5N1 viral particles from chickens in his backyard flock.

It’s unlikely. According to Topham, some animal studies suggest consuming the virus is less likely to make you sick than, say, inhaling droplets containing the virus. And the CDC says there’s no evidence that anyone who’s caught avian influenza got sick from handling cooked poultry products.

 “These viruses are not that hardy,” Topham says. “As long as things are cooked, you’re fine.” So, whether you get your eggs, poultry, and beef from the grocery store or your local farmer’s market, be sure to cook them properly. That means cooking poultry and eggs to an internal temperature of 165˚F, ground beef to 160˚F, and cuts of beef to 145˚F and allowing them to rest for three minutes before eating. You’ll also want to thoroughly scrub any cutting boards and cooking utensils you use to prepare these foods. 

When it comes to foods you typically don’t cook, notably dairy, it’s important to avoid unpasteurized milk (also known as raw milk) and any products made from raw milk, such as soft cheese, ice cream, and yogurt. Pasteurization, which involves briefly heating milk to a high temperature, inactivates influenza viruses along with a host of other dangerous infectious agents that raw milk may harbor. You may have heard reports that avian influenza virus can be detected even in pasteurized milk, but those virus particles are inactive. “It’s not live virus, and it can’t infect you, and it can’t make you sick,” Topham says.

The percentage of people who had the virus and died from it in the 1997 outbreak in Asia may sound frightening. But in that outbreak and other outbreaks with high fatality rates, severe or deadly symptoms have occurred primarily in those who lived in close proximity to domestic birds and had limited access to medical care, Schaffner says. 

Generally, people in the U.S. don’t need to worry about getting infected right now, Topham says. The documented infections in people here so far “are very isolated cases and usually with circumstances where we can identify that there’s been intense exposure, very close contact, or repeated contact,” he notes.

Most U.S. infections have been mild, with eye redness the predominant symptom. Some people have also reported fever, coughing, and congestion. Mild cases usually last a few days to less than two weeks, according to the CDC, while moderate to severe cases may cause high fever, shortness of breath, confusion, and seizures, and symptoms may take a couple of weeks to subside 

Are some people more susceptible? We’ve long known that young children, adults older than 65, immunocompromised people, and those with underlying health conditions are at higher risk for seasonal flu. If bird flu were to shift, and start to spread more easily among people, it’s likely the same factors would be associated with higher risks for severe illness.

It’s reasonable to take the same steps you do to protect yourself against any virus, such as washing your hands regularly and cleaning surfaces around your home. And in addition to steering clear of raw milk products, avoid direct contact with sick or dead birds. If you find a dead bird, the CDC recommends reporting it to your state health department or wildlife agency. If you need to remove a dead bird on your property, the New York City’s health department advises wearing gloves and a facemask, and placing the animal in a double-bagged garbage bag, which the CDC says you can then place in a trash receptacle outside your home. Afterward, throw away the gloves and mask and wash your hands thoroughly. If you work with animals and suspect you could have been infected, reach out to your state or local health department for potential testing—your healthcare provider can help you get in contact.

If you raise backyard chickens, and any look sick, don’t touch them or anything that might be contaminated with their feces or bodily fluids without disposable gloves, safety goggles, an N95 respirator, rubber boots, and disposable, fluid-resistant coveralls. Sick birds may seem sluggish, dirty, have discharge from the eyes or nose, or diarrhea, and may eat or drink less than normal. The CDC provides more step-by-step instructions on how to safely handle suspected backyard flock infections.

In theory, cats and dogs that go outside could become infected with bird flu if they eat or otherwise are exposed to sick or dead birds. And the Los Angeles County Department of Public Health has documented a handful of cases of H5N1 influenza in cats who had eaten raw pet food or raw milk products.

To protect your pets, don’t feed them raw milk, products made from raw milk, or raw pet food. As much as possible, keep pets away from contact with wild animals and birds, especially any that are dead or appear sick. 

There’s no publicly available vaccine against H5N1 influenza, but the CDC has developed a number of candidates. Also, stockpiles of older H5N1 vaccines are in the process of being updated to better match the strains currently circulating, according to Schaffner.

Researchers are closely tracking avian flu cases around the globe. Infected commercial flocks are culled to try to prevent further spread. Scientists are also closely watching for possible changes in the virus—specifically, if it becomes able to spread from person to person—that would make it a larger concern.

That could lead to a pandemic, “because the world’s population would be completely susceptible, with no prior experience of this bird flu,” Schaffner says.