Swine flu is a respiratory disease spread between pigs and humans through coughing, sneezing, or direct contact. It can cause symptoms like fever, cough, sore throat, and fatigue. To prevent catching or spreading swine flu, wash hands regularly with soap, avoid contact with infected people, and clean surfaces frequently. The document provides information on swine flu symptoms, transmission, prevention tips, and testing locations in Delhi for those concerned they may have the virus.