"Highly pathogenic" bird flu has jumped from wild birds to poultry. Here's what we know.

A major bird flu outbreak would be an economic disaster

Avian influenza is tremendously dangerous for birds, but it poses less of a threat to people. According to Matthew Koci, a viral immunologist at North Carolina State University, the disease "can kill, depending on the strain, between 60 to 100 percent of [a] flock."

The outbreak "should be relatively minor" if "we catch it early and we can keep it contained to a couple of farms," he told a CBS affiliate in North Carolina. If government and industry don't manage to keep the burgeoning epidemic under control, "the economic impact could be devastating," he said.

In the U.S., chickens and turkeys outnumber humans more than two-to-one.

These reports have pushed the U.S. agricultural sector into high alert, with state authorities, federal regulators, and industry activating plans designed for situations like this. The last major outbreak happened seven years ago and was centered in the Midwest. That wave of bird flu led to the death of more than 50 million turkeys and chickens, either from the disease or in precautionary culling. Exports of poultry products fell by roughly $1.3 billion, and the federal government spent approximately $900 million to fix the problem.

Avian influenza does not pose a significant risk to the general public 

While these reports mark the first time the disease has been found in U.S. commercial poultry since 2020, there have been plenty of reports of avian influenza in the wild bird population, which the USDA monitors with a special disease surveillance program.

As of writing, the agency has reported 139 positive cases in a wide range of species this year. Those sick birds were found up and down the east coast, from Florida to New Hampshire. The agency says the findings are "not unexpected" because wild birds "can carry the disease to new areas when migrating" and often show no symptoms. The agency says that inspectors anticipate finding more cases as sampling ramps up during spring migration.

Luckily, bird flu generally doesn't pose much of a threat to the general public. At least, it hasn't so far. According to the CDC, the designation of "highly pathogenic" refers to the virus's ability to spread in birds, not humans. In fact, no human in the U.S. is known to have ever contracted a highly pathogenic strain of the disease. In the last two decades, just four people in the U.S. have contracted the disease. All of them were infected with low pathogenic strains of the virus.

More than 700 cases have been reported worldwide since 2003, mostly in workers who directly contacted infected birds. While the illness can cause severe complications and even death, the agency says it does not spread easily among humans.