For the study, swine flu virus strains were isolated from patients affected by the recent pandemic. They were then assessed for their ability to cause disease in four animal models.
In mice, ferrets and macaques, infection with the new swine-origin influenza viruses was associated with more severe disease than a seasonal H1N1 strain.
The researchers, from the University of Wisconsin, also found that all antiviral drugs tested, including Tamiflu, were effective in cell culture against the new virus, lending support to the use of the drugs as a first line of defence against a pandemic.
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