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.

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.

Shah said the updated precautions are aimed at keeping workers healthy and slowing the spread of the H5N1 virus, known as bird flu. "The less room we give this virus to run, the fewer chances it has to cause harm or to change," Shah said. "And the best way ...