Yunnan sudden death syndrome
Yunnan sudden death syndrome refers to a series of cardiac arrests that 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 1,800–2,400 m (5,900–7,900 ft).
Source: Wikipedia — Yunnan sudden death syndrome (CC BY-SA 4.0)