WASHINGTON (AP) - Put swine flu in a room with other strains of influenza and it doesn't mix into a new superbug - it takes over, researchers reported Tuesday.
University of Maryland researchers deliberately co-infected ferrets to examine one of the worst fears about the new swine flu. But fortunately, the flu didn't mutate. The researchers carefully swabbed the ferrets' nasal cavities and found no evidence of gene-swapping.
The animals who caught both kinds of flu, however, had worse symptoms. And they easily spread the new swine flu, what scientists formally call the 2009 H1N1 virus, to their uninfected ferret neighbors - but didn't spread regular winter flu strains nearly as easily.
The Maryland study reinforces concern about how easily swine flu may sweep through the country.