The CDC reports the potential discovery of the bird flu virus in a few wastewater sites.
On Tuesday, the Centers for Disease Control and Prevention (CDC) stated that there is currently no conclusive evidence of bird flu transmission among humans, despite an ongoing outbreak of the virus in dairy cows.
Recent data from 189 wastewater sampling sites, as of May 4, revealed elevated levels of influenza A virus detected at several locations nationwide, including Alaska, California, Florida, Illinois, and Kansas. The strain circulating among cows, known as H5N1, falls under the category of influenza A. Notably, one site in Saline County, Kansas, exhibited significantly heightened levels of flu virus for this time of year. The CDC also reported four positive tests among herds in Kansas during April.
However, it remains unclear whether the high virus levels in Kansas wastewater samples are solely from human waste or if they also include agricultural runoff. Furthermore, it’s uncertain whether these elevated levels indicate infections in humans, cows, birds, or other animals. Despite the findings, there hasn’t been a noticeable increase in flu-like illnesses in recent weeks, according to the CDC.
Jonathan Yoder, deputy director of the CDC’s division of infectious disease readiness and innovation, expressed a desire to understand the factors behind the influenza A increase, particularly during what is typically considered a low transmission season for the virus.
Regarding the situation in Saline County, a representative from a major hospital did not provide comment, while Dr. Cameron Wolfe, an infectious disease expert at Duke University School of Medicine, described the CDC’s new data as reassuring. Wolfe noted that it’s currently mid-May, a time when flu activity is typically low, and he hasn’t observed an increase in flu-like illnesses in his medical practice.
As of Tuesday, 42 herds across nine states—Kansas, Colorado, Idaho, Michigan, New Mexico, North Carolina, Ohio, South Dakota, and Texas—have been affected. The CDC is monitoring 260 individuals exposed to infected dairy cows for flu-like symptoms, with 33 people tested for the virus. To date, only one person—a dairy farm worker in Texas—has been diagnosed with bird flu linked to the dairy cow outbreak. He experienced severe conjunctivitis (pinkeye) but has since recovered.