Severe acute respiratory syndrome (SARS) is a serious form of pneumonia. It is caused by a coronavirus (SARS-CoV) that was first identified in 2003. Infection with the SARS virus causes acute respiratory distress (severe breathing difficulty) and sometimes death. SARS was first reported in Asia in February 2003. The illness spread to more than two dozen countries in North America, South America, Europe, and Asia before the SARS global outbreak of 2003 was contained. Still there is no medication that is known to treat SARS. Treatment is supportive.