萨斯 is a phonetic transliteration of the English acronym SARS. The full Chinese medical term is
严重急性呼吸综合征 (yánzhòng jíxìng hūxī zōnghézhēng). Also written as
非典 (fēidiǎn), short for
非典型肺炎 (atypical pneumonia), which is the more common colloquial term in mainland China.