In 1962, at a little boarding school in the tiny village of Katasha, in what is now Tanzania, a small group of children started doing what kids often do: they began laughing.
The laughter was jovial at first, so much in fact that other students not privy to the original humor joined in as well. Some kids laughed so hard they cried. It was fun. It was innocent.
But then it wasn't.
It's very difficult to breathe when laughing. That's why you can only laugh for about twenty seconds. However, some of the kids had been laughing almost constantly for ten minutes! They began experiencing pain in their throats, and some started fainting. Soon screams rent the air, creating a cacophony with the unceasing laughter.
The laughter continued off and on throughout the rest of the day, slowly spreading like a contagion amongst the students. Laughing children even spread the condition to their parents when they returned home. Two physicians, A.M. Rankin and P.J. Philip, who were called in to examine the situation, described the malady as follows:
"The onset is sudden, with attacks of laughing and crying lasting for a few minutes to a few hours, followed by a respite and then a recurrence. The attack is accompanied by restlessness and on occasions violence when restraint is attempted. The patient may say that things are moving around in the head and that she fears that someone is running after her."
Strangely, the physicians didn't find any abnormal physical signs among the afflicted, apart from slightly dilated pupils.
Six weeks after the original outbreak, the boarding school was forced to shut down. Ninety-five of the 159 pupils had been "infected." In the twelve months that followed, the laughter spread to two other villages and fourteen schools, affecting approximately 1,000 people. Locals called the epidemic "Enwara Yokusheka" -- "the illness of laughing" -- or "Akajanja," which simply means "madness."
In their later examinations, Rankin and Philip managed to rule out a host of physical factors, such as poisoning or viruses. To date, the best explanation remains of the psychological sort, specifically mass hysteria, which is the spontaneous manifestation of hysterical physical symptoms by a group of people.
"Now we call it Mass Psychogenic Illness," Purdue University's Christian Hempelmann told the Chicago Tribune. "It's psychogenic, meaning it is all in the minds of the people who showed the symptoms. It's not caused by an element in the environment, like food poisoning or a toxin. There is an underlying shared stress factor in the population... It's an easy way for them to express that something is wrong."
Mass hysteria begins with a few people experiencing symptoms of severe stress, such as fits, headaches, or nausea. When these manifest, they become rapidly magnified throughout the rest of the stressed population, driven by our innate tendencies to imitate and follow others with whom we closely sympathize.
After about 18 months, Tanzania's laughter epidemic subsided completely. There were no fatalities. Residents of Katasha and the surrounding villages still laughed of course, but their merriment was now normal; it didn't persist to pain nor spread beyond normal bounds.
(Image: Pal Teravagimov / Shutterstock.com)