Tanganyika laughter epidemic
The Tanganyika laughter epidemic of 1962 was an outbreak of mass hysteria in or near the village of Kashasha on the western coast of Lake Victoria in Tanganyika (now part of Tanzania), near the border with Uganda. == History == The laughter epidemic began on January 30, 1962, at a mission-run boarding school for girls in Kashasha.
Source: Wikipedia — Tanganyika laughter epidemic (CC BY-SA 4.0)