H1N1 flu may not mutate with seasonal flu

COLLEGE PARK, Md., Sept. 1 (UPI) -- University of Maryland researchers say laboratory tests indicate the H1N1 flu virus spread quickly but it may not mutate into a "superbug" this fall.

Lead researcher Daniel Perez and colleagues conducted laboratory tests and found the H1N1 flu did not take a virulent turn when combined with other strains of seasonal flu, HealthDay News reported. But it did spread more rapidly than the other viruses, confirming the need for swine flu vaccinations, Perez said.

Perez and colleagues exposed ferrets to three different viruses, the H1N1 swine flu and two seasonal strains of flu. The study, published in the journal PLoS Currents, found the H1N1 strain dominated the others, reproducing by about twice as much.

"I'm not surprised to find that the pandemic virus is more infectious, simply because it's new, so hosts haven't had a chance to build immunity yet," Perez said in a statement. "Meanwhile, the older strains encounter resistance from hosts' immunity to them."

The researchers also found some ferrets infected with H1N1 flu as well as one of the more familiar seasonal viruses developed intestinal illness in addition to respiratory symptoms.