
Reuters - Tue Jul 26,12:06 PM ET
Strains of the influenza virus are constantly swapping genes among
themselves and giving rise to new, dangerous strains at a rate
faster than previously believed, U.S. researchers reported on July
25, 2005. File photo shows an Influenza Virus Vaccine vial sitting
on the counter of medical center in Great Neck, New York October
22, 2004. (Shannon Stapleton/Reuters)