Novel H1N1 pandemic: when pigs fly.

On April 21, 2009, the "Morbidity and Mortality Weekly Report" Dispatch was entitled "Swine Influenza A (H1N1) Infection in 2 Children-Southern California, March to April 2009".[1,2] This marked the beginning of a long awaited influenza pandemic. Within days, there were reports of widespread influenza with high mortality in young adults in Mexico. These cases were subsequently confirmed to be due to a novel strain. The viral genome is part swine, part avian, and part human influenza; thus, it is truly novel.[3] Following the initial 2 cases in California, there were dozens and then hundreds of cases throughout the United States and across the Northern hemisphere.