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A single modification in the protein found on the surface of the highly pathogenic avian influenza (HPAI) H5N1 influenza virus currently circulating in U.S. dairy cows could potentially allow for easier transmission among humans, according to new research funded by the National Institutes of Health (NIH) and published in the journal Science. This discovery highlights the critical need for continued surveillance and monitoring of H5N1 for potential genetic changes that could make the virus more transmissible in humans. Currently, bovine H5N1 strains aren’t known to be spreadable between people, but infections have happened in individuals exposed to infected wild birds, poultry, dairy cows, and other mammals. As part of our ongoing pandemic preparedness, we’ve been monitoring the H5N1 virus for years to understand how viral genetic mutations occur naturally and assess their impact on transmissibility. This new research is a crucial piece of the puzzle.
Understanding H5N1 Avian Influenza: A Closer Look
Influenza viruses, like H5N1, attach to cells using a surface protein called hemagglutinin (HA). This HA latches onto sugar molecule receptors on cells to initiate infection. Avian influenza viruses haven’t often infected humans because human upper respiratory tracts lack the specific avian-type cell receptors found in birds. Scientists worry about the possibility of viruses evolving to recognize human-type receptors, enabling infection and spread among people.
H5N1 Avian Influenza and Viral Mutation
Scientists at Scripps Research used a specific H5N1 strain isolated from a US human infection, to explore how mutations in the HA gene sequence impacted the protein’s binding to avian versus human-type cell receptors. They introduced several naturally occurring mutations into the viral HA protein and found one, designated Q226L, that improved the protein’s ability to attach to human-type cell receptors, especially when paired with an additional mutation. Crucially, these genetic modifications were only made to the HA protein, and the whole virus wasn’t used in this experiment.
Implications of This Research on Human Transmission
This finding, while significant, doesn’t mean HPAI H5N1 is about to become a widespread pandemic. Likely, several additional mutations are necessary for the virus to efficiently spread among people. Given the increasing number of H5N1 human cases stemming from close contact with infected animals, this research emphasizes the importance of maintaining outbreak control efforts and ongoing genomic surveillance. By meticulously monitoring for the emergence of these genetic changes, we can better prepare our public health defenses.
The Role of Surveillance and Monitoring
Our research reinforces the need for rigorous monitoring and surveillance of HPAI H5N1. We need to remain vigilant for any genetic changes that could make the virus more easily transmissible among people. This vigilance is key to maintaining public health preparedness, especially as human exposure to infected animals continues.
This research was partially funded by the National Institute of Allergy and Infectious Diseases (NIAID) through its Centers of Excellence for Influenza Research and Response program.
I hope this explanation helps to illustrate the nuances of this important scientific discovery. Leave a comment below with your thoughts on this research. Share this article with your friends to help spread awareness.
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