Dairy Cattle H5N1 Virus Stays Bird-Adapted with Minimal Human Transmission

Recent research from St. Jude Children's Research Hospital has provided insights into the behavior of H5N1 avian influenza virus detected in dairy cattle since 2024. Despite initial concerns that the virus might adapt to infect humans more effectively, the findings suggest that the virus remains primarily bird-adapted with limited risk of human transmission.

Scientists analyzed a panel of H5N1 viruses isolated from dairy cows and found they closely resembled avian influenza strains both genetically and biologically. These cow-derived viruses could infect mammals through direct contact but showed no capacity to spread through airborne transmission, the primary mode of human-to-human infection. This indicates that, in its current form, the virus does not pose a significant threat of becoming a pandemic in humans.

While the viruses from cows have caused at least 41 known human infections via close contact, laboratory studies suggest that existing flu vaccines and antiviral treatments remain effective against these strains. The research included testing the efficacy of common antiviral drugs, which showed no signs of resistance, providing reassurance that current therapeutics could manage infections should they occur.

Despite these reassuring findings, health experts emphasize vigilance, especially for individuals working closely with infected cattle or consuming raw dairy products. The virus continues to evolve, and each infection presents an opportunity for it to mutate and possibly gain greater infectivity in humans.

In conclusion, while the current data suggest a low risk for widespread human infection, monitoring and preventive measures are essential to prevent potential future mutations that could alter the virus's threat level.

Source: https://medicalxpress.com/news/2025-07-dairy-cattle-h5n1-virus-birds.html