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.

The CDC study included 45 workers in Michigan and 70 in Colorado tested between June and ... Related Articles Health | Bird flu outbreaks die down, but Colorado keeps monitoring cows and poultry Health | Colorado orders dairies to test milk to curb spread ...

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.