Bird flu: What are the human symptoms and how does it spread?
At least nine U.S. farm workers had tested positive for the H5N1 strain of avian influenza, or bird flu, as ...
At least nine U.S. farm workers had tested positive for the H5N1 strain of avian influenza, or bird flu, as ...
The polio vaccine has all but obliterated the illness that once killed thousands and paralyzed 15,000 people nationwide every year. ...