Yunnan sudden death syndrome

Yunnan sudden death syndrome is a sudden unexplained death from cardiac arrest, which afflicted significant numbers of rural villagers in Yunnan province in southwest China. Cases almost always occurred during the midsummer rainy season (from June to August), at an altitude of 1800 - 2400 m. An estimated 400 deaths occurred over three decades.

The cause of the deaths was unknown until researchers from the Chinese Center for Disease Control and Prevention isolated a significant factor common in every case: a toxic mushroom which was unintentionally gathered and consumed during wild mushroom harvests in the region. Previously the syndrome was thought to be caused by Keshan disease, which is caused by the Coxsackie virus.

The mushroom, Trogia venenata, is also known as 'Little White'. It was determined that families collecting fungi to sell had been eating these mushrooms as they have no commercial value. Three amino acids present in the mushrooms have been shown to be toxic. The mushrooms have also been shown to contain very high quantities of barium, which may have caused some of the deaths.

In the hours before death, about two-thirds of the victims experienced nausea, dizziness, heart palpitations, seizures and fatigue.