For Your Health (1)

Swine flu arose as a normal, non-lethal flu in the spring or 1918, but somehow, over the following months -- no-one knows how or where -- it mutated into something more severe. Then in 1933, the 50s and again in the seventies a strain of the same flu known as the Russian H1N1 broke out - Bill Bryson. The current virus of 2009 is known as: Pandemic H1N1/09 virus. "This new strain appears to be a result of reassortment of human influenza and swine influenza viruses, in all four different strains of subtype H1N1." - Wikipedia