Texas Dairy Worker Contracts Bird Flu from Cow, Recovers

A dairy farm worker in Texas has contracted avian influenza A (H5N1) from cattle, marking a highly likely case of cow-to-human transmission of the virus, according to a detailed case report from the Centers for Disease Control and Prevention (CDC) and the Texas Department of State Health Services. The worker, who exhibited only mild symptoms of conjunctivitis in both eyes, was treated with oral oseltamivir (Tamiflu) and recovered rapidly.

Why this matters: This case highlights the potential for animal-to-human transmission of the H5N1 virus, which could have significant implications for public health and pandemic preparedness. It also underscores the need for increased vigilance and proactive measures to prevent further transmission between animals and humans, particularly in high-risk settings like dairy farms.

The worker developed painful red, swollen, weeping eyes with burst blood vessels in late March 2024, but had no fever and clear lungs. He had no contact with sick or dead birds or other animals, but had repeated, direct, close contact with dairy cows in the same part of Texas with other infected herds. Genome sequencing revealed that the H5N1 virus isolated from the worker was closely related to viruses detected in dairy cattle and wild birds in Texas in March.

Swabs of the patient's eyes revealed they were teeming with the H5N1 virus, while there was hardly any virus in his lungs, suggesting possible infection through his eyes rather than lungs. The authors noted that "if cow-to-human transmission occurred, to our knowledge, this would be the first reported case of mammal-to-human HPAI A (H5N1) virus transmission reported worldwide."

The case highlights concerns over the pandemic potential of H5N1 viruses and the need for preventive measures, particularly in high-risk settings like dairy farms. The worker wore gloves but no other protective equipment when working with the cows. Health officials tested other sick dairy workers in Texas, including some with red eyes, but they turned out to have other illnesses, not bird flu.

Farmworkers may be hesitant to report symptoms due to economic desperation and lack of paid sick leave. "For farmworkers specifically, certainly these are folks that are living in a state of economic desperation, and what they're not going to do is test for something if they don't have paid sick leave, because they cannot afford to be sent home and told to stay home and not work," said Elizabeth Strater, director of strategic campaigns for United Farm Workers.

Key Takeaways

• Texas dairy farm worker contracts H5N1 avian flu from cattle, likely first case of cow-to-human transmission.
• Worker had mild symptoms, treated with Tamiflu, and recovered rapidly.
• Infection likely occurred through eyes, not lungs, highlighting need for protective equipment.
• Farmworkers may hesitate to report symptoms due to economic concerns and lack of paid sick leave.
• CDC seeks farms for epidemiological studies to understand avian flu outbreak and protect human health.