SARS is an infectious respiratory illness caused by a coronavirus. The first cases of SARS occurred in late 2002 in the Guangdong Province of the People's Republic of China. Because of the contagious nature of the disease and the delayed public-health response, the epidemic spread rapidly around the globe. Final statistics from the World Health Organization showed 8,096 reported illnesses and 774 deaths.

The rapid transmission and high mortality rate (about 10%) of SARS drew international attention and concern. Fortunately, efforts to identify and quarantine infected people proved highly effective. By July 2003, sustained human-to-human transmission of SARS had been eliminated. This was a public-health triumph that is often under-appreciated. Although illnesses such as anthrax or bird flu are potential threats, SARS was a very real problem. Unfortunately, future outbreaks of SARS are still possible because the virus lives in some wild bats and civets in China and also exists in laboratory cultures. In fact, there were a few human cases of SARS in 2004 as a result of laboratory accidents in the People's Republic of China. No human cases have been identified since.