Following a CDC study showing bird flu exposure among dairy workers, health officials recommend increased testing and preventative measures for farmworkers, even if they show no symptoms, to prevent virus spread and mutation.

After a new study showed that bird flu has spread to dairy farm workers more often than previously known, the US Centers for Disease Control and Prevention is expanding its recommendations for testing and treatment of workers on farms where animals have tested positive.

The updated testing and Tamiflu recommendations aim to "drive that risk down as low as possible," Shah said. Bird flu hasn't affected the nation’s dairy supply. Milk is safe to drink once it is pasteurized, a process that kills pathogens. (This story has ...