Swine flu may refer to influenza in pigs or to an infection in humans caused by the H1N1v or H3N2v viruses. Learn more about how to prevent.
WebMD explains the H1N1 flu virus (swine flu), what causes it, and its nervous system, neuromuscular, or metabolic problems; Adults and.
Most U.S. cases of H1N1 swine flu have been in children and young adults. It's not clear whether this will change as the H1N1 pandemic.