The H5 bird flu is widespread in wild birds and is causing outbreaks in U.S. poultry and dairy farms, the CDC says. There have been outbreaks in 443 U.S. dairy herds, and 48 states have reported outbreaks in poultry.

Seven percent of tested workers on dairy farms where cows were infected with bird flu caught the virus themselves, according to a new study.

By Grace WadeThere may be more bird flu cases in humans in the US than we previously thought. Health departments in two states took blood tests of workers on dairy farms known to have hosted infected cattle and found that about 7 per cent of them have antibodies for the disease.