Summary

Every summer, around the time the monsoon rains begin to fall in late June, a killer stalks the rugged highlands of Yunnan Province in southwest China. For more than 30 years, people of all ages have been dropping dead from sudden cardiac arrest in northern Yunnan. The vast majority of deaths occur during the rainy season, from June to August. Yunnan Unknown Cause Sudden Death, as it is called, often strikes in clusters, so the first victim in a village instills dread in the rest of the inhabitants. Since 1978, more than 400 deaths and several dozen nonfatal cardiac cases have been attributed to the syndrome. But this summer, people across Yunnan may be able to rest easy. After a 5-year investigation, a team led by the Chinese Center for Disease Control and Prevention believes it has uncovered the syndrome's chief cause. CDC and Yunnan Provincial Health Department have embarked on a campaign to warn against eating an innocuous-looking mushroom deemed so trifling that most villages don't even have a name for it. If they have fingered the real culprit—known for lack of a better description as the "little white mushroom"—then this summer could be the first in decades without a death from the syndrome. The case is not closed, however. Some researchers believe that a substantial percentage of syndrome deaths may be from another cause.