SARS, in full severe acute respiratory syndrome, highly contagious respiratory illness characterized by a persistent fever, headache, and bodily discomfort, followed by a dry cough that may progress to great difficulty in breathing. SARS appeared in November 2002 in Guangdong province, China, where it was first diagnosed as an atypical pneumonia. . . . SARS is caused by a coronavirus, a type of virus usually associated with pneumonia and the common cold. Read the entire article from Britannica online here.