Over the weekend, California state health officials warned the public to avoid drinking raw milk from a Fresno-based dairy farm that was being sold in stores. H5N1, the virus driving the current bird flu outbreak, was detected in a retail milk sample.

New research and discussions with dairy farmers in the Central Valley suggests H5N1 bird flu is more widespread among people than the reported numbers indicate.

Bird flu virus has been found in a batch of raw milk sold in California, and consumers should not drink it, the state Department of Public Health warned Sunday.