Material about this "respiratory disease of pigs caused by type A influenza. ... In late March and early April 2009, cases of human infection with swine influenza A (H1N1) viruses were first reported in Southern California and near San Antonio, Texas," and have been reported in other states and internationally. Provides background, fact sheets and guidance, widget, and reports on U.S. human cases of swine flu. From the Centers for Disease Control and Prevention (CDC).