The Tanganyika laughter epidemic of 1962 was an outbreak of mass hysteria – or mass psychogenic illness (MPI) – rumored to have occurred in or near the village of Kashasha on the western coast of Lake Victoria in the modern nation of Tanzania (formerly Tanganyika) near the border of Kenya.
The laughter epidemic began on January 30, 1962, at a mission-run boarding school for girls in Kashasha. The laughter started with three girls and spread haphazardly throughout the school, affecting 95 of the 159 pupils, aged 12–18. Symptoms lasted from a few hours to 16 days in those affected. The teaching staff were not affected but reported that students were unable to concentrate on their lessons. The school was forced to close down on March 18, 1962.
After the school was closed and the students were sent home, the epidemic spread to Nshamba, a village that was home to several of the girls. In April and May, 217 people had laughing attacks in the village, most of them being school children and young adults. The Kashasha school was reopened on May 21, only to be closed again at the end of June. In June, the laughing epidemic spread to Ramashenye girls’ middle school, near Bukoba, affecting 48 girls.
The school from which the epidemic sprang was sued; the children and parents transmitted it to the surrounding area. Other schools, Kashasha itself, and another village, comprising thousands of people, were all affected to some degree. Six to eighteen months after it started, the phenomenon died off. The following symptoms were reported on an equally massive scale as the reports of the laughter itself: pain, fainting, flatulence, respiratory problems, rashes, attacks of crying, and random screaming. In total 14 schools were shut down and 1000 people were affected.
The Chicago Tribune in 2003, asks Christian F. Hempelmann, a University of Purdue linguistics doctorate candidate at the time some questions regarding her research into the 1962 epidemic.
Something did happen in Tanganyika. The bad news is, it had nothing to do with humor. There was no merriment. Laughter was one of many symptoms.
Read more of her interview here