CDC Expands Bird Flu Testing for Dairy Workers Amid Asymptomatic Infections

On Thursday, November 7th, the Centers for Disease Control and Prevention (CDC) announced new guidelines for testing dairy workers exposed to bird flu (H5N1) following a study that revealed asymptomatic cases among workers. Conducted on farms in Colorado and Michigan, the CDC study tested 115 workers, with blood samples showing that eight had been exposed to the virus, even though only half of them remembered experiencing mild symptoms like red eyes or a runny nose.

Previously, the CDC recommended testing only workers showing symptoms after contact with infected animals. Now, however, the agency advises testing all exposed workers, even if they don’t show symptoms, and providing Tamiflu as a precaution. This measure, aimed at reducing the risk of illness and preventing possible mutations of the virus, is part of a broader initiative to limit H5N1’s spread and monitor any potential shifts in its behavior. “Simply put, the less room we give this virus to run, the fewer chances it has to cause harm or to change,” said Dr. Nirav Shah, the CDC’s Principal Deputy Director.

The new approach emerged after CDC officials found a lack of personal protective equipment (PPE) use among farm workers, many of whom were unaware that the animals they were handling were infected. In the study, most infected workers reported milking cows and cleaning the milking parlor without protective gear. The CDC emphasizes the importance of PPE and has issued culturally tailored safety guidance to educate workers, many of whom speak Spanish.

To date, 46 people in the U.S. have been diagnosed with H5N1, all linked to contact with infected livestock, with cases concentrated in states like California and Washington. Fortunately, all reported cases have been mild, with symptoms similar to conjunctivitis or minor respiratory issues, contrasting with past global outbreaks where the H5N1 strain showed high mortality rates.

The CDC assures the public that commercial milk and beef supplies remain safe, with no evidence of contamination. However, experts emphasize that minimizing human infection on farms is crucial to preventing wider outbreaks. “Containing the spread of infection in cows is believed to be the best way to control transmission to farm workers,” noted Lori Tremmel Freeman of the National Association of County and City Health Officials.

The CDC continues to work with local health departments to monitor bird flu’s progression, reiterating that the risk to the broader public remains low.