A single mutation in the H5N1 flu virus is enough for the avian flu virus to increase its ability to adhere to human cells, thus increasing the risk of transmission between people and potentially favoring the emergence of a pandemic.
Ours in study published in ‘Science‘, which underlines the urgent need to monitor the evolution of H5N1, especially in a context where this virus has spread rapidly among herds of cattle in North America.
Since its emergence in North America in 2021, the H5N1 2.3.4.4b variant has infected different species, including birds, marine mammals and humans. By 2024, it had already been detected in 282 dairy herds in 14 US states, and several human cases of infection had been recorded.
Although human-to-human transmission has not yet occurred, the adaptation of the virus to infect humans remains a serious concern for public health experts.
The study, led by Ting-Hui Lin, showed how a specific mutation in the hemagglutinin protein (HA) of the virus could change its affinity for human-type receptors. This mutation, Gln 226 Leu, significantly improves the virus’s ability to adhere to the receptors of human cells.
Furthermore, a second mutation, Asn 224 Lys, further reinforces this affinity, bringing the H5N1 at a level of binding to human receptors similar to that observed in the 2009 H1N1 virus.
Crucial discovery
This discovery is crucial as it shows how a single mutation could allow the H5N1 virus to adapt to infect humans.
However, the researchers emphasize that this mutation alone does not guarantee transmission between people. Other genetic modifications, such as those that affect viral replication, would still be necessary for the virus to spread effectively between humans.
The researchers used advanced testing to analyze how the modified H5N1 hemagglutinin protein interacted with human receptors. The results showed that the Q226L mutation greatly facilitates the binding of the virus to human cells, indicating that H5N1 could evolve towards a greater ability to infect and transmit between humans.
However, this evolution has not yet been observed in the currently circulating virus.
The study highlights the importance of continuing surveillance for mutations in H5N1 and other avian influenza viruses. While there is no immediate cause for alarm, researchers warn that even a mutation that alters how the virus binds to human cells should be closely monitored for possible signs of increased transmissibility.
«The constant surveillance of the genetic changes “It gives us an advantage to anticipate possible increases in transmissibility,” says Ian Wilson, co-author of the study. “This type of research helps us identify key mutations that could trigger a pandemic, allowing us to take appropriate measures to protect global public health.”
These findings highlight the risk of interspecies transmission, particularly in people who work closely with livestock or in situations of co-infection with seasonal influenza viruses. Experts warn that, given the history of the H5N1 virus and its ability to adapt, surveillance and monitoring of its mutations are essential to prevent a possible future pandemic.
#single #mutation #H5N1 #flu #virus #facilitate #human #transmission
