Scientists discover mutation that could enhance the ability of the H5N1 bird flu virus to infect humans and potentially enable its transmission.
As the H5N1 bird flu virus spreads rapidly among animals in the United States scientists are closely monitoring for any signs of human-to-human transmission. Recent research indicates that the virus may require only a single mutation to gain the ability to spread between humans.
H5N1 is an extremely deadly virus with a fatality rate of 50% among infected humans. Experts emphasize the importance of tracking animal infections to control the virus prevent mutations and reduce the risk of human infection thereby averting a potential global outbreak.
Typically bird flu viruses require several mutations to pose a significant threat to humans. However scientists at the Scripps Research Institute in California warn that H5N1 may adapt more rapidly this time raising concerns about the possibility of a pandemic.
The study published in the journal Science on December 5 2024 underscores the urgent need to monitor the evolution of H5N1.
According to a release by the Scripps Research Institute there are currently no confirmed cases of H5N1 transmission between humans. Human infections have been linked to direct contact with contaminated environments or infected animals, including birds, poultry, dairy cows and other species. Public health officials remain concerned however about the virus potentially evolving to transmit efficiently between people which could lead to a deadly pandemic.
The flu virus infects hosts through a protein called hemagglutinin which binds to glycan receptors on the surfaces of host cells. Glycans chains of sugar molecules found on cell surface proteins serve as binding sites for certain viruses. Avian influenza viruses like H5N1 typically target sialic acid containing glycan receptors found in birds (avian type receptors). However if the virus evolves to recognize sialylated glycan receptors present in humans (human type receptors) it could potentially infect and spread between people.
Monitoring changes in receptor specificity the way a virus recognizes host cells is essential because receptor binding is a critical step toward transmissibility explains Ian Wilson, DPhil, co-senior author and the Hansen Professor of Structural Biology at Scripps Research. That said receptor mutations alone do not guarantee the virus will spread between humans.
Ting Hui Lin a postdoctoral associate at Scripps Research and the study first author adds the findings illustrate how easily this virus could evolve to recognize human type receptors. However our study does not suggest that this evolution has already occurred or that the current H5N1 virus with this mutation would necessarily be transmissible between humans.
