Bird Flu Outbreak: Vets Contract Virus Without Reporting

A new study from the Centers for Disease Control and Prevention (CDC) has uncovered three dairy veterinarians who contracted bird flu (H5N1) without any reported exposure to infected cows. This latest finding suggests a more widespread infection in the U.S. than previously reported.

Undetected Infections Among Vets

The study, published in the CDC’s Morbidity and Mortality Weekly Report, involved antibody testing of 150 veterinarians practicing in 46 U.S. states. Among these, three tested positive for the H5N1 virus.

Notably, none of the three vets had known contact with sick cows. One of them had worked exclusively in Georgia and South Carolina, where no bird flu outbreaks among dairy herds had been reported.

Broader Implications

Experts suggest that the virus might be more prevalent in cattle populations across the country than currently acknowledged. Seema Lakdawala, a virologist at Emory University, stated, “We do not know the extent of this outbreak in the U.S. There are clearly infections happening that we’re missing.”

Since March 2024, bird flu has been confirmed in over 950 herds in 16 states and has affected 68 people, with 41 of them having direct contact with sick cows.

Delayed Publication

The study’s publication was initially delayed due to the Trump administration’s pause on health and science communications. Dr. Nahid Bhadelia, director of the Boston University Center on Emerging Infectious Diseases, emphasized the importance of this data for public health preparedness.

The research was conducted at a veterinary conference in September 2024, with participating veterinarians working in various U.S. states and Canada. Twenty-five of these vets had reported exposure to cows suspected of having bird flu, but none of them tested positive for antibodies.

Routine Contact and Infections

The study revealed that none of the three vets who tested positive recalled experiencing flu-like symptoms. They also did not report wearing safety equipment like masks or goggles, which are not typically required in areas considered unaffected.

Lakdawala noted that the vets involved in the study are involved in the full care of the animals, suggesting that they may come into contact with various bodily fluids and excretions from the cows, which could lead to infection.

Need for Enhanced Testing

The findings underscore the necessity for more robust testing methods, including asymptomatic dairy workers and veterinarians, and broader surveillance of the milk supply. The USDA announced a national program to test bulk milk samples in December, and as of February 2025, 40 states have been actively participating.

Testing efforts have already led to the discovery of a new variant of the virus in Nevada, distinct from the one affecting dairy herds over the past year.

Dr. Bhadelia advises that all states should adopt bulk milk testing to avoid complacency.

Conclusion

The revelation of bird flu infections in veterinarians without known exposure highlights the complexity and spread of the virus. It emphasizes the need for more comprehensive testing and increased awareness among veterinarians, dairy workers, and public health officials.

Stay informed about the latest developments in this ongoing situation to protect public and animal health.

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