Video By: Centers for Disease Control and Prevention br August 2016: 8 human cases of Swine flu confirmed in Lansing, Michigan. br Swine flu is a human respiratory infection caused by an influenza strain that started in pigs. br Swine flu was first recognized in the 1919 pandemic and still circulates as a seasonal flu virus. Swine flu is caused by the H1N1 virus strain, which started in pigs. br Symptoms include fever, cough, sore throat, chills, and body aches. br Typical treatment includes rest, pain relievers, and fluids.