The swine flu that hit the world in 1918 was first discovered in the spring of that year. Just like now, it was a mild flu. It is a virus that normally is seen in pigs. The pig virus really does not know how to attack the body in a human, but by December, the flu had mutated into a super human virus and killed over 10 million people. The swine flu is credited with ending WW1. The fear is, that this virus will do the same, and by December of this year, it will come back and be a killer again.