CDC Reports Potentially Troublesome Mutations in Bird Flu Found in Louisiana Patient

MONDAY, Dec. 30, 2024 (HealthDay News) — Federal health officials have confirmed unsettling new details about the first United States case of severe bird flu, reported recently in a hospitalized patient in Louisiana.

Genetic samples from the patient contained mutations that could, in theory, help the virus better infect human cells.

Importantly, these mutations were observed in the later stages of infection and were not present in the virus samples taken from the backyard poultry flock that infected the patient, a media report from The New York Times shows.

This suggests that the changes occurred as the virus adapted to its human host, rather than spreading widely in nature, the U.S. Centers for Disease Control and Prevention (CDC) said in an update published Dec. 26.

Still, experts are concerned about the broader implications. “Every additional human case gives H5N1 more opportunities to adapt to people,” The Times reported.

“It has the potential to really harm a lot of people,” Angela Rasmussen, a virologist at the Vaccine and Infectious Disease Organization in Canada, said.

In a positive finding, the CDC emphasized that there is no evidence the virus has spread from the Louisiana patient to others, and the mutations alone are unlikely to spread from person to person.

CDC scientists also confirmed, however, that the Louisiana virus samples are closely related to candidate vaccine strains already developed for bird flu.

Yet, Rasmussen questioned why those vaccines are not being used to protect high-risk groups, such as farmworkers, who have the greatest exposure.

Sixty-six other cases of H5N1 avian flu have been reported in people across the United States since April of this year, but have resulted in relatively mild symptoms that resolved after treatment.

However, the Louisiana case — the first-ever reported H5N1 illness in that state — “marks the first instance of severe illness linked to the virus in the United States,” the CDC said in a previous statement.

Most of the other bird-to-human cases have occurred in workers at major poultry farms; “this is the first case of H5N1 bird flu in the U.S. that has been linked to exposure to a backyard flock,” the CDC noted.

The agency also stressed that an eventual case of severe H5N1 avian flu in an American was “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 stated.

The case does serve as a reminder, however, that anyone with close exposures to birds needs to be careful. “This means that backyard flock owners, hunters and other bird enthusiasts should also take precautions,” the agency said.

In a health alert issued Dec. 13, state officials said the case involves a resident of southwestern Louisiana.

“The individual had exposure to sick and dead birds that are suspected to have been infected with H5N1,” the virus that causes bird flu.