Much less serious than the Dancing Plague (but equally as humorous) was the Tanganyika laughter epidemic of 1962. On January 30th, three girls at a boarding school in Kashasha, Tanzania began laughing. The laughter spread like wildfire throughout the school, affecting nearly 60% of the students. Symptoms of those affected lasted from a few hours to 16 days. The behavior was so disruptive, the school was forced to close down.
Soon after, the epidemic had spread to neighboring villages. In April and May, over 200 people had long disruptive laughing attacks. By June, the epidemic had spread to another school affecting an additional 50 students. In July, another outbreak occurred in nearby Kanyangereka, and another two schools were closed.
According to reports, the laughter was incapacitating when it struck. General pain, fainting, respiratory problems, rashes, crying bouts, and random screaming were all common traits of those affected. By the end of the epidemic 14 schools were shut down and over 1,000 people had been afflicted – but there were no known deaths reported. To this day, scientists do not have an explanation for this one-time epidemic that occurred in Tanzania. The most popular hypothesis was a form of Mass Psychogenic Illness (MPI) – otherwise known as mass hysteria – most likely brought about by tainted food sources. That all those affected were isolated to a single area supports this theory, although the fact that the laughter epidemic only appeared to affect children (and not adults) has researchers stumped.
Perhaps even more fascinating is that this type of hysteria has only one recorded instance in history.