Clusters of sudden unexplained death associated with the mushroom, Trogia venenata, in rural Yunnan Province, China

Since the late 1970's, time-space clusters of sudden unexplained death (SUD) in northwest Yunnan, China have alarmed the public and health authorities. From 2006-2009, we initiated enhanced surveillance for SUD to identify a cause, and we warned villagers to avoid eating unfamiliar mushrooms. We established surveillance for SUD, defined as follows: sudden onset of serious, unexplained physical impairment followed by death in