The first cases of disease in humans are believed to have occurred in Guangdong province, China, in November 2002, but the syndrome was only recognised three months later.
Arvatakse, et esimesed haigusjuhtumid inimesel tekkisid Hiinas Guangdongi provintsis 2002. aasta novembris, kuid sündroom tuvastati alles kolm kuud hiljem.