Single Mutation in Bovine Influenza H5N1 Raises Human Transmission Concerns: Study

New Delhi: A recent study has revealed that a single genetic mutation in the haemagglutinin (HA) protein of the bovine influenza H5N1 virus enables the virus to bind human receptors, sparking concerns about its potential for human-to-human transmission. Researchers found that the Gln226Leu mutation completely switches the virus's receptor binding from avian-type to human-type receptors, a significant step towards human adaptation.

The study, led by Dr. Ting-Hui Lin and colleagues from The Scripps Research Institute, analysed the HA protein from the first human-infecting bovine H5N1 virus, detected in Texas in 2024. Using advanced structural and biochemical techniques, they demonstrated how this mutation changes the virus's ability to infect human cells.

“Our findings highlight the importance of monitoring mutations in H5N1 viruses,” said Dr. Ian A. Wilson, one of the lead researchers. “A single mutation like Gln226Leu can drastically increase the risk of the virus adapting to humans, underscoring the need for heightened surveillance and preparedness.”

The study identified the Gln226Leu mutation as a pivotal change that allows the bovine influenza H5N1 virus to bind strongly to human-type receptors while losing its affinity for avian-type receptors, marking a critical shift in host specificity.

Using advanced structural analyses, researchers solved the crystal structures of the mutant HA protein bound to human receptor analogues, uncovering the molecular mechanisms behind this receptor switch.

While no human-to-human transmission of the virus has been observed to date, the adaptation poses a significant risk by increasing the pandemic potential of the virus, highlighting the need for continued vigilance and monitoring.

Dr. James C. Paulson, another senior researcher, emphasized, “The discovery of this mutation in a bovine H5N1 strain raises the alarm for possible zoonotic spillovers. Our study provides critical insights into the mechanisms of viral adaptation and highlights the urgency of global monitoring.”

The bovine H5N1 virus has already infected humans and other species, including cats and poultry, through direct contact. While current infections have been mild, further mutations could lead to increased transmissibility among humans.

“This research is a call to action,” added Dr. Lin. “Continuous monitoring and genomic analysis of circulating H5N1 strains are essential to prevent potential outbreaks.”

The study underscores the critical need for collaboration between veterinary and public health sectors to address emerging zoonotic threats. Researchers recommend enhanced surveillance, particularly in dairy cattle and poultry farms, to identify and contain any new mutations in H5N1 viruses.

With the growing threat of zoonotic diseases, this study serves as a stark reminder of how quickly a virus can adapt to infect humans. The identification of the Gln226Leu mutation provides valuable insights for developing preventive strategies and preparing for potential future pandemics.