Researchers challenge 'superbug theory' in animal tests using three flu strains
TUESDAY, Sept. 1 (HealthDay News) -- Fears that the H1N1 swine flu will turn into a "superbug" this year may be unfounded, say researchers at the University of Maryland.
In laboratory tests, the virus responsible for the swine flu pandemic did not take a virulent turn when combined with other strains of seasonal flu. But it did spread more rapidly than the other viruses, confirming the need for swine flu vaccinations, the researchers said.
The researchers exposed ferrets to three different viruses, the H1N1 swine flu and two seasonal strains of flu. The H1N1 strain dominated the others, reproducing by about twice as much, the researchers reported online in the journal PLoS Currents.
"The H1N1 pandemic virus has a clear biological advantage over the two main seasonal flu strains and all the makings of a virus fully adapted to humans," Daniel Perez, the lead researcher and program director of the University of Maryland-based Prevention and Control of Avian Influenza Coordinated Agricultural Project, said in a Sept. 1 university news release.
"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. Meanwhile, the older strains encounter resistance from hosts' immunity to them," Perez added.
In the lab tests, after being infected with the new swine flu virus and one of the more familiar seasonal viruses (H3N2), some of the ferrets developed intestinal illness in addition to respiratory symptoms. The researchers hope further studies will determine if this type of co-infection and multiple symptoms are behind some of the deaths caused by the new pandemic virus.
Also, the swine flu virus caused infections deeper in the ferrets' respiratory system than the H1 and H3 seasonal viruses, which remained in the nasal passag
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