The document provides information about swine flu and answers 16 questions from the CDC about the virus. It discusses that there are different subtypes of swine influenza viruses that infect pigs, including H1N1, H1N2, H3N2, and H3N1. It notes that humans can become infected with swine flu from direct contact with pigs, though human-to-human transmission is rare. Symptoms in humans are similar to seasonal flu. While human infections are uncommon, cases increase risk of a new pandemic strain emerging. There is no vaccine to protect people but antiviral medications can treat infections.