Doctors fear that one day the influenza virus will mutate to become as lethal as the so-called Spanish flu pandemic of 1918, which killed up to 50 million people worldwide. Science has never identified the virus and no one knows why it was so deadly. But last year an expedition of experts journeyed to the Arctic Circle to to exhume the graves of seven victims of the 1918 flu in the hope of solving the mystery.
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