In late 2002, cases of life-threatening respiratory disease with no identifiable cause were reported from Guangdong Province China, and they were followed by reports from other countries. The syndrome was designated "severe acute respiratory syndrome" (SARS). Investigators used a combination of traditional methods and molecular techniques to identitify the unknown pathogen. Researches showed that SARS is caused by a new coronavirus, never detected before and which is not related to - any of the known coronaviruses.