CDC confirms first ‘severe’ case of H5N1 bird flu in US

The CDC announced the first “severe” case of H5N1 bird flu in the U.S., according to a press release issued Wednesday. The good news? The person who contracted the virus appears to have gotten it from backyard poultry, meaning they didn’t get it through human-to-human transmission, which has long been feared as something that could fuel mutations and a new pandemic in humans. The bad news? Human cases of bird flu continue to rise as the man who mismanaged America’s last pandemic is about to take over again.

The severe case announced by the CDC on Wednesday was first confirmed on Dec. 13 after tests came back for a patient in Louisiana, the agency said in press release. The virus in this case was identified as genotype D1.1, which is related to other cases of D1.1 found in people from Washington state and British Columbia, Canada. This genotype is different from the B3.13 genotype found in US dairy cows, which is the dominant method of human infection. The state of California, which has the highest number of known infections in dairy herds in the country at 645, declared a state of emergency on Wednesday.

Human cases of D1.1 have come from birds, although the new case in Louisiana is the first from a backyard flock. Most human cases come from agricultural workers exposed to commercial birds. There was also a case in Missouri and a case in California where the route of infection was not determined because there was no known exposure to farm animals. Recent wastewater detection of bird flu in many states such as Florida, Maine, and New Jersey is also confusing because there are no known cases of infected birds or cattle in those states.

The CDC’s announcement Wednesday did not include any biographical information about the Louisiana case and The Washington Post reports that CDC officials have refused to provide even basic information about the timeline of how this person may have been infected or his symptoms. The only information shared in this regard is that they have flu-like symptoms.

CDC launched a bird flu tracking tool online which breaks down the confirmed human cases, as well as the US states where they were identified and the animal believed to be the source of the infection. There are a total of 61 confirmed cases in eight states, although suspected cases are not included. Delaware, for example, currently has a suspicious case this has not yet been confirmed by tests. If this case is confirmed by the CDC, Delaware would become the ninth state to have human cases of bird flu during this outbreak. Delaware also recently saw the detection of the virus in wastewater.

There are no known cases of bird flu in humans in the US through consumption of milk or beef, but the possibility has been a recent concern. Pasteurization kills bird flu in milk, but a recent study showed the virus can survive five days in raw milk. President-elect Donald Trump appointed Robert F. Kennedy Jr., an outspoken advocate of raw milk, to head the US Department of Health and Human Services. Cats that were recently seen drinking raw milk in California have died, and Los Angeles health officials believe they infected with bird flu.

Even with this new serious case of bird flu in Louisiana, the CDC remains steadfast in its belief that the threat to the broader US population is still low.

“A sporadic case of severe H5N1 bird flu disease in a human is not unexpected; Avian influenza A(H5N1) infection was previously associated with severe human illness in other countries in 2024. and previous years, including illness leading to death,” the CDC said in a statement.

“No human-to-human spread of H5 avian influenza has been detected,” the statement continued. “This case does not change CDC’s overall assessment of the immediate public health risk from H5N1 avian influenza, which remains low.”