A patient over the age of 65 was hospitalized in Louisiana more than a week ago.
The avian flu virus detected in a critically ill patient in the United States has mutated, adapting more effectively to human respiratory pathways. While this mutation raises concerns, U.S. authorities emphasize that there is currently no evidence the virus in its mutated form has spread to other individuals.
The patient, hospitalized in Louisiana, presented with severe respiratory symptoms associated with H5N1 avian flu after contact with sick and deceased poultry.
The Centers for Disease Control and Prevention (CDC) analyzed the virus and identified genetic changes in a portion of the virus found in the patient’s throat. These mutations enhance the virus’s ability to bind to specific receptors in the upper respiratory tract of humans.
However, the same genetic changes were not observed in the poultry kept by the patient. CDC experts believe these mutations likely occurred as the virus replicated within the patient, who was already suffering from advanced illness. Experts consulted by AFP caution that it is too early to determine whether these mutations make the virus more transmissible or capable of causing severe disease in humans.
“This specific mutation is one step toward increasing the virus’s transmissibility,” stated Angela Rasmussen, a virologist at Canada’s University of Saskatchewan. She added, however, that it is not the sole factor required for such a development.
Thijs Kuiken, a researcher at Erasmus MC University Medical Center in the Netherlands, echoed this sentiment. He explained that while the virus’s ability to bind effectively to cells in the human upper respiratory tract is critical, it is not sufficient for efficient human-to-human transmission. Successful replication of the virus involves several additional steps in the human cell cycle.
Rasmussen expressed greater concern about the overall spread of avian flu than about this specific case in Louisiana. In 2024, the CDC reported 65 confirmed cases of avian flu in humans across the U.S., with more cases likely going undetected, particularly among workers in poultry and dairy facilities.
