SciFocus/Dec 6, 2024 — A recent study published in Science highlights a chilling revelation: a single genetic mutation in the bovine H5N1 influenza virus can switch its receptor preference from avian to human types, heightening the risk of a pandemic. Conducted by Lin et al., the study analyzed hemagglutinin (HA) mutations in the H5N1 strain linked to outbreaks in dairy cattle and mild human cases in the U.S.
The findings underscore the critical need for vigilant surveillance of zoonotic influenza viruses, given the potential for these mutations to enable efficient human-to-human transmission.
“Study reveals that a single mutation could dramatically increase the likelihood of H5N1 adapting to humans, underscoring the pandemic risk of zoonotic viruses.”
Key Highlights:
- Mutation Discovery: A single Gln226Leu mutation in the hemagglutinin protein of H5N1 changes its receptor specificity from avian to human types.
- Wider Implications: While other mutations usually require three or more changes, this singular mutation significantly raises the probability of adaptation to humans.
- Structural Insights: Crystal structures reveal how the mutation enhances binding to human receptors, a step critical for human transmission.
- Epidemiological Concern: Human infections in 2024 associated with the bovine strain (clade 2.3.4.4b) were mild but highlight the evolutionary potential of the virus.
- Historical Context: H5N1, with a known fatality rate of up to 30% in humans, remains a major pandemic threat.
- Additional Risk Factors: Coinfection with seasonal influenza could lead to reassortment, creating hybrid viruses more adept at human transmission.
Call to Action:
The study emphasizes the importance of:
- Continuous surveillance of emerging mutations in avian and mammalian H5N1 strains.
- Developing proactive measures for detecting and mitigating zoonotic virus spillovers.
- Investigating additional factors, like HA stability and NA activity, that contribute to transmissibility.
This discovery is a stark reminder of the thin line separating zoonotic infections from global pandemics. The world must remain prepared.
