Severe Acute Respiratory Syndrome (SARS) is a form of atypical pneumonia occurring in a person who has traveled to a country with an outbreak or come in contact with a person with SARS. SARS, the cause of which has not yet been identified, begins as an influenza-like illness, with such symptoms as rapid onset of high fever, muscle aches, headache, sore throat, dry cough and shortness of breath.