嚴重急性呼吸系統綜合症
Severe acute respiratory syndrome (SARS) is caused by a new type of coronavirus. Other coronaviruses were known to cause mild infections in humans, so the virulence and rapid spread of this novel virus strain caused alarm among health professionals as well as public fear. The fears of a major pandemic were not realised, and by July 2003, after causing around 8,000 cases and 800 deaths, the outbreak had ended. The exact origin of the SARS virus is not known, but evidence suggests that it came from bats.