Single Mutation in H5N1 Bird Flu Virus Enhances Human Cell Attachment, Raising Pandemic Concerns
Single Mutation in Bird Flu Virus Raises Pandemic Concerns
Scripps Research Study Finds H5N1 Could More easily Infect Humans
A recent study has revealed a worrying development in the H5N1 ”bird flu” virus currently circulating in the U.S. Scientists at Scripps Research discovered that a single mutation in the virus, which has recently infected dairy cows, could considerably increase its ability to attach to human cells. This finding, published in Science on december 5, 2024, highlights the urgent need to closely monitor the evolution of H5N1.
While there are currently no documented cases of H5N1 spreading between humans, public health officials remain concerned about the virus’s potential to evolve and trigger a new pandemic.
How Viruses Jump Species
Flu viruses infect their hosts by attaching to specific sugar molecules called glycans on the surface of cells. Avian influenza viruses like H5N1 primarily target glycans found in birds. However, if they evolve to recognize glycans found in humans, they could gain the ability to infect and possibly spread among people.
“Monitoring changes in receptor specificity – how a virus recognizes host cells – is crucial because receptor binding is a key step toward transmissibility,” says Ian Wilson, DPhil, co-senior author and the Hansen Professor of Structural Biology at Scripps Research.
A Single Change,a Big Difference
Past instances of avian viruses adapting to infect humans required multiple mutations. however, the Scripps Research team found that a single amino acid change in the H5N1 2.3.4.4b strain, isolated from the first human case linked to a bovine H5N1 infection in the U.S.,could dramatically shift its receptor preference towards human-type glycans.
“the findings demonstrate how easily this virus could evolve to recognize human-type receptors,” says first author Ting-Hui Lin, a postdoctoral associate at Scripps Research.
A Red Flag, Not an Alarm
While this mutation is a cause for concern, it doesn’t necessarily mean the virus is immediately capable of spreading between humans. Other genetic changes are likely needed for efficient human-to-human transmission.
Nevertheless, the study underscores the importance of proactive surveillance of H5N1 and similar avian flu strains.
“Continuing to track genetic changes as they happen will give us an edge in preparing for signs of increased transmissibility,” adds Wilson. “This type of research helps us understand what mutations to watch for and how to respond appropriately.”
Bird flu Mutation Raises Pandemic Concerns: An Interview wiht Dr.Ian Wilson
NewsDirectory3: Dr. wilson, your recent study published in Science revealed a concerning mutation in the H5N1 bird flu virus. Can you explain what makes this mutation so worrisome?
Dr. Ian Wilson: Certainly. What we found is that a single amino acid change in the H5N1 virus, specifically the 2.3.4.4b strain found in the first human case linked to a bovine infection in the U.S., can significantly change its ability to bind to human cells.
NewsDirectory3: Could you elaborate on how viruses like H5N1 infect their hosts?
Dr. Ian Wilson: Flu viruses infect cells by attaching to specific sugar molecules called glycans on the surface of cells. Avian influenza viruses like H5N1 primarily target glycans found in birds.Though, if thay acquire the ability to recognize glycans found in humans, they could perhaps infect and spread among people.
NewsDirectory3: In the past, wasn’t it thought that multiple mutations were needed for avian influenza viruses to adapt to infect humans?
Dr. Ian Wilson: Yes, that’s been the historical understanding. However, our findings show that a single mutation can already lead to a significant shift towards recognizing human-type glycans.
NewsDirectory3: Does this meen we are on the verge of a pandemic?
Dr. Ian Wilson: Not necessarily. While this mutation is a red flag, it doesn’t necessarily mean the virus is promptly capable of spreading efficiently between humans. Other genetic changes are likely needed for that to occur.
NewsDirectory3: What are the implications of your study for public health efforts?
Dr. Ian Wilson: Our study highlights the urgent need for continued surveillance of H5N1 and similar avian flu strains. Tracking these genetic changes allows us to anticipate and prepare for potential increases in transmissibility. Understanding which mutations to watch for will help us respond appropriately to evolving threats.