Severe acute respiratory syndrome (SARS) is a serious illness caused by a virus called a coronavirus. SARS was first described in Asia in February 2003. It was discovered in Chinese patients who had fever and severe breathing problems. In spring 2003, SARS quickly spread among humans with close person-to-person contact. More than 8000 people in Asia, Europe, and North and South America became sick with SARS. Some places, such as Hong Kong, set up quarantine hospitals to handle the large numbers of patients with the illness. By July 2003, the SARS outbreak was contained. Because SARS is a newly discovered viral illness, most doctors don't know how patients presented with the illness or what their outcomes were.