Another cause for concern: flu season is underway in the U.S., and as seasonal influenza virus goes around, “humans, ourselves, could be a mixing vessel,” Davis says. If a person were simultaneously infected with bird flu and seasonal flu, the two viruses could theoretically combine to create a more transmissible strain.

Testing of dairy workers in Michigan and Colorado shows that more workers may be catching bird flu than thought.

The number of H5N1 bird flu cases in dairy cattle workers in the U.S. may be much higher than reported, indicates a new CDC study.

People have been hearing a lot about H5N1 bird flu -- or highly pathogenic avian influenza -- since a B.C. teen became the first human to get the virus in Canada and is in hospital.