Since December, an outbreak of swine flu in India has killed more than 1,200 people, and a new study suggests that the strain has acquired mutations that make it more dangerous than previously circulating strains of H1N1 influenza.
Since December, an outbreak of swine flu in India has killed more than 1,200 people, and a new study suggests that the strain has acquired mutations that make it more dangerous than previously circulating strains of H1N1 influenza.