A highly contagious bird flu has spread across more than 30 states, according to the U.S. Department of Agriculture.
This week alone, the strain, known as H5N1, likely killed hundreds of birds at a lake northwest of Chicago, and at least three bald eagles in Georgia. Two cases of H5N1 were also found in birds at U.S. zoos.
Since January, the USDA has detected H5N1 among tens of millions of wild birds and domestic and commercial flocks, predominantly in the South, Midwest and the East Coast. Nearly 27 million chickens and turkeys have been killed to prevent the virus's spread.
So far, no cases have been reported among people in the U.S., and the risk to public health is low, according to the Centers for Disease Control and Prevention. Just one recent human infection has been documented: a person in England who raised birds got sick. That case, reported in January, was asymptomatic.
But the bird flu outbreak is affecting consumers' lives in the form of rising egg and poultry prices. The average weekly price for large eggs is up 44 percent compared with this time last year, the USDA reported Monday. Wholesale poultry prices rose 4 percent in February, and the USDA predicts they could climb between 9 and 12 percent in 2022.
'Watchful eyes around people working in poultry facilities'
Over time, it's possible that a small number of people could contract the virus. Past versions of H5N1 flu infected 864 people between 2003 and 2021, according to the World Health Organization. About half of those cases were fatal.
"Sporadic human infections with current H5N1 bird flu viruses would not be surprising, especially among people with exposures who may not be taking recommended precautions," the CDC says on its website.
But Andrew Bowman, an associate professor at Ohio State University’s College of Veterinary Medicine, said he'd be surprised to see this particular bird flu spill over into people on a large scale. Ancestors of this virus have been circulating in other parts of the world for a while, he said, and people have been relatively spared.
"The current lineage we’re seeing is really not fit to go into mammalian hosts, so it’s got to be pretty unlikely," Bowman said.
If a person does get infected, disease experts should be able to quickly test them, he added.
"We have a lot of watchful eyes around people working in poultry facilities, especially if they’re involved in a flock that becomes infected," Bowman said.
Still, the Covid pandemic has made some experts hesitant to make guesses about the bird flu's trajectory.
"Look at coronavirus. There were a couple of outbreaks of MERS and SARS in the past and they didn’t go anywhere, and then look what happened," said Dr. Elizabeth Buckles, an associate clinical professor at Cornell University’s College of Veterinary Medicine.
The history and spread of H5N1
Ancestors of the current H5N1 bird flu were first detected in geese in China in 1996. The current set of H5N1 bird flu viruses was identified in Europe in 2020, then found in North and South Carolina in January.
The recent U.S. outbreak is the worst since 2015, when multiple bird flu strains, including some H5N1 viruses, spread across the country. Nearly 50 million birds were slaughtered or died. Bowman said this new outbreak appears to be even more geographically widespread.
Experts attribute the spread of H5N1 to the migration of wild birds, which pass the virus through saliva, mucus and droppings.
The Raptor Center at the University of Minnesota recently recommended in a Facebook post that people to stop using bird feeders or bird baths to stop birds from congregating.
But experts said songbirds aren't the main drivers of the spread.
"There’s 10,000 species of birds and (the virus) doesn’t infect them all the same," Bowman said. "For the primary transmission, we’re really focused on the waterfowl, especially the dabbling ducks."
Buckles said it's important to keep chickens and turkeys away from wild birds to prevent the virus from entering our food supply. As a precaution, people should cook poultry and eggs to a temperature of 165 degrees Fahrenheit, according to the CDC.
If you've come into contact with a bird, wash your hands, Buckles added.
"Anytime that you have animals — I don’t care whether it’s your pet dog or your chicken — you need to practice good hand hygiene," she said. "We all know how wash for 20 seconds with soap and water. That applies to this as as well."