What is SARS?

According to the Centers for Disease Control and Prevention (CDC), SARS was recognized as a global threat in March 2003. The viral disease first appeared in Southern China in November, 2002 and spread to more than 24 countries in Asia, Europe, North America, and South America. There have not been any new cases of SARS since 2004, and the risk is relatively low.

A virus known as SARS-associated coronavirus (SARS-CoV) causes the illness. Coronaviruses commonly cause mild to moderate upper-respiratory illness in humans, but can cause respiratory, gastrointestinal, liver, and neurologic diseases in animals.

As researchers quickly rushed to stop the spread of SARS in 2003, they learned more about the characteristics of SARS-CoV, which had never been identified before. While they still have not confirmed the disease's origin, many believe SARS-CoV first occurred in animals and then spread to humans.