Antivirals still effective against mutated bird flu strain
Researchers at Texas Biomed have identified nine mutations in a human strain of bird flu (H5N1) isolated in Texas. These mutations make the strain more capable of causing severe disease and replicating in human cells, particularly in brain tissue. However, approved antiviral medications remain effective against the virus, offering a critical line of defense.
H5N1, commonly found in wild birds and poultry, began spreading to mammals, including dairy cattle, in 2024. The virus infected dozens of people, mostly farm workers, by early 2025. While human cases often result in mild illness, one fatality linked to infected chickens occurred in January 2025.
“The clock is ticking for the virus to evolve to more easily infect and potentially transmit from human to human, which would be a concern,” said Professor Luis Martinez-Sobrido of Texas Biomed.
In recent studies, researchers compared human and bovine H5N1 strains. They found that the human strain replicated more efficiently and caused more severe disease than the bovine strain.
Despite these differences, FDA-approved antivirals remain effective, providing a buffer against a potential pandemic until vaccines are widely available.
Ongoing studies aim to understand why H5N1 infects such a wide range of mammals and causes varying levels of disease severity.
Recommendations include a One Health approach, focusing on eradicating bird flu from dairy cattle through decontamination and stricter quarantine measures.
For more information, visit www.texasbiomed.org.