Testing of the latest human case of bird flu has revealed a “remarkable” mutation in the virus, officials said.
The case, which was discovered this month in a Michigan dairy worker, marks the second human infection linked to the multi-state H5N1 outbreak among U.S. livestock.
Genomic sequencing has now found a change in the virus compared to a previous infection in a Texas dairy worker, raising concerns that the virus is evolving to better infect people.
The small change in the virus's genetic makeup is “associated with viral adaptation to mammalian hosts,” the Center for Disease Control said in a statement. published on Friday.
This change has also been found to result in an improvement in virus replication and disease severity in mice during studies with avian flu viruses, the agency added.
“This is precisely why I have tried to draw attention to the in-depth analysis of every virus from cows, cats and humans infected with H5N1, which is necessary for a rapid and effective global response to the development of vaccines and antivirals” , says Dr. Rick. Bright, an immunologist and flu expert, on X (formerly Twitter).
Despite the evolution of the virus, the CDC emphasizes that the strain is still closely related to the H5N1 group circulating among U.S. dairy cattle, and closely matches the two vaccine candidates currently available to manufacturers, should they be needed.
Experts believe it's likely we'll see more human cases of H5N1 among dairy workers in the coming weeks and months as surveillance efforts ramp up across America.