Clusters of Sudden Unexplained Death Associated with the Mushroom, Trogia venenata, in Rural Yunnan Province, China

Abstract

IntroductionSince 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.MethodsWe established surveillance for SUD, defined as follows: sudden onset of serious, unexplained physical impairment followed by death in <24 hours. A mild case was onset of any illness in a member of the family or close socially related group of a SUD victim within 1 week of a SUD. We interviewed witnesses of SUD and mild case-persons to identify exposures to potentially toxic substances. We tested blood from mild cases, villagers, and for standard biochemical, enzyme, and electrolyte markers of disease.ResultsWe identified 33 SUD, a 73% decline from 2002–2005, distributed among 21 villages of 11 counties. We found a previously undescribed mushroom, Trogia venenata, was eaten by 5 of 7 families with SUD clusters compared to 0 of 31 other control-families from the same villages. In T. venenata–exposed persons SUD was characterized by sudden loss of consciousness during normal activities. This mushroom grew nearby 75% of 61 villages that had time-space SUD clusters from 1975 to 2009 compared to 17% of 18 villages with only single SUD (p<0.001, Fisher's exact test).DiscussionEpidemiologic data has implicated T. venenata as a probable cause of clusters of SUD in northwestern Yunnan Province. Warnings to villagers about eating this mushroom should continue.

Mycetism: A Review of the Recent Literature

“…Elevated AST, ALT, LDH, and CK are also reported [65,68,69]; however, in one study, only elevation of AST was statistically significant, when compared to controls [68]. Postmortem examinations of 29 cases revealed mild, focal lymphocytic myocarditis, with breakage of the muscle fibers [68]. Postmortem examination also revealed occasional lymphocytic infiltration of the liver, pulmonary alveolar edema, acute kidney necrosis, hepatocyte necrosis, and congestion of the liver, lung, or spleen [68].…”

“…Ventricular tachycardia and fibrillation may precede death. Elevated AST, ALT, LDH, and CK are also reported [65,68,69]; however, in one study, only elevation of AST was statistically significant, when compared to controls [68]. Postmortem examinations of 29 cases revealed mild, focal lymphocytic myocarditis, with breakage of the muscle fibers [68].…”

“…These mushrooms also contain the proconvulsant toxin, gammaguanidinobutyric acid, which is structurally similar to GABA [22,66]. The exact toxin responsible for the syndrome is not yet well established [67,68] Initially, patients report nausea, vomiting, diarrhea, abdominal pain, and fatigue. Recurrent syncope and eventual sudden unexpected death may occur.…”

“…Postmortem examinations of 29 cases revealed mild, focal lymphocytic myocarditis, with breakage of the muscle fibers [68]. Postmortem examination also revealed occasional lymphocytic infiltration of the liver, pulmonary alveolar edema, acute kidney necrosis, hepatocyte necrosis, and congestion of the liver, lung, or spleen [68]. The public campaign to educate against T. venenata consumption has dramatically reduced the incidence of SUD [66,68].…”

Evidence against Barium in the Mushroom Trogia venenata as a Cause of Sudden Unexpected Deaths in Yunnan, China

“…ince 1978, over 400 sudden unexpected deaths (SUDs) have been reported in Yunnan in southwest China (11,13). The vast majority of these deaths occurred in apparently healthy people in northwest Yunnan and over 90% clustered in the rainy season between June and August, generating significant concerns among health authorities, the general public, and all levels of government (13,14).…”