CDC Confirms First ‘Severe’ Case of H5N1 Bird Flu in U.S.

The CDC has declared the first “severe” case of H5N1 bird flu in the U.S., according to a press release published Wednesday. The good news? The person who contracted the virus appears to have gotten it from backyard poultry, meaning they didn’t acquire it from human-to-human transmission, which has been long feared as something that could fuel mutations and a new pandemic in humans. The bad news? Bird flu cases in humans continue to tick up as the guy who grossly mismanaged America’s last pandemic is about to take power 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 a press release. The virus in this case was identified as D1.1 genotype, which is related to other D1.1 cases that have been found in humans from Washington state and British Columbia, Canada. That genotype is different from the B3.13 genotype detected in dairy cows throughout the U.S. which has been the dominant method of human infection. The state of California, which has the highest number of known dairy herd infections in the country at 645, declared a state of emergency Wednesday.

The D1.1 cases in humans have come from birds, though the new case in Louisiana is the first acquired from a backyard flock. Most human cases have come from farm workers exposed to commercial poultry. There was also a case in Missouri and a case in California where the route of infections had not been determined since they had no known exposure to farm animals. Recent wastewater detection of bird flu in many states like Florida, Maine, and New Jersey has also been perplexing since there are no known cases of infected birds or cattle in those states.

The CDC’s announcement Wednesday didn’t include any biographical information about the case in Louisiana and The Washington Post reports CDC officials declined to provide even basic information about the timeline of how this person may have been infected or their symptoms. The only information shared in that regard is that they have symptoms consistent with flu.

The CDC launched a bird flu tracker online that breaks down the confirmed cases in humans, as well as the U.S. states where they’ve been identified, and the animal believed to have been the source of the infection. There are a total of 61 confirmed cases in eight states, though suspected cases are not included. Delaware, for instance, currently has a suspected case that hasn’t been confirmed by testing yet. If that case is confirmed by the CDC Delaware will become the ninth state to see human cases of bird flu during this outbreak. Delaware has notably also seen wastewater detection of the virus recently.

There have been no known human cases of bird flu acquired in the U.S. through the consumption of milk or beef, but that possibility has been a concern lately. Pasteurization kills bird flu in milk, but a recent study showed the virus can survive for five days in raw milk. Incoming president Donald Trump has named Robert F. Kennedy Jr., a vocal advocate of raw milk, to be the head of the U.S. Department of Health and Human Services. Cats that had been seen drinking raw milk recently in California died and health officials in Los Angeles believe they were 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 population in the U.S. is still low.

“A sporadic case of severe H5N1 bird flu illness in a person is not unexpected; avian influenza A(H5N1) virus infection has previously been associated with severe human illness in other countries during 2024 and prior years, including illness resulting in death,” the CDC said in a statement.

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