US health authorities have confirmed that the patient hospitalized in Louisiana with a severe form of H5N1 avian flu had genetic mutations of the virus. These changes, seen in part of the virus taken from the patient’s throat, could indicate “increased binding” with certain cellular receptors in the human airways, the US Centers for Disease Control and Prevention (CDC) said on Thursday.
These mutations, probably occurring during the replication of the virus in the patient’s body, mark a significant step in the potential adaptation of H5N1 to humans. However, the CDC emphasized that no human-to-human transmission has been identified and these changes were not detected in infected birds, including those in this patient’s environment.
What are the implications?
According to Angela Rasmussen, a virologist at the University of Saskatchewan in Canada, the identified mutation could allow the virus to enter cells in the upper respiratory tract more easily. “It is a necessary step for a virus to become more contagious, but I insist that it is not the only one,” she clarified. Further testing in animal models will be necessary to confirm these observations.
Experts remain cautious about the implications of these changes. Thijs Kuiken, a specialist at the Erasmus University Medical Center in the Netherlands, believes that these mutations could lead to less serious infections. “The virus becomes more likely to infect the upper respiratory tract, causing runny nose or sore throat, rather than the lower respiratory tract,” he explained. This could reduce the risk of serious complications such as pneumonia.
The world on the brink of a pandemic?
Angela Rasmussen insisted that these observations do not mean the world is on the brink of a pandemic. “This is not a sign that we are getting closer to that eventuality,” she said. Since the start of the year, 65 mild cases of avian flu have been detected in the United States, in addition to the serious case in Louisiana.
To read, our file on avian flu
The CDC believes, however, that some cases may have gone unnoticed. Although H5N1 first appeared in 1996, a significant increase in outbreaks of infection has been observed since 2020, affecting more and more mammals. The situation remains under close monitoring, with analyzes underway to better understand the potential impact of the genetic mutations observed.
