When Laughter (Almost) Kills

Laughter is the best medicine, or so the old saying goes. But what if laughter wasn’t the best medicine? What if laughter was the disease?

It all started in a boarding school in Tanganyika in January of 1962. These were heady times for the nation on Africa’s east coast: the country had only received its independence from Britain a few weeks previously, and it had yet to merge with Zanzibar to form the modern nation of Tanzania. Perhaps the joy of independence or the stress of what the future might hold was just too much. No one, it seems, will ever know for sure what the root cause of the epidemic was. All that’s known for sure is that someone told someone else a joke at an all-girls boarding school at Kashasha village on the morning of January 30, 1962. The three students involved in the joke became subject to uncontrollable fits of laughter, sometimes lasting only a few minutes, other times lasting as long as 16 hours. Since laughter is, in some sense, contagious, the laughter fits quickly spread to 95 of the school’s 159 students. The attacks left no permanent injuries, but the laughter fits did mean that few students could learn anything, so the school was shut down on March 18th.

You’ve probably seen a movie or TV show about communicable diseases where the doctors plot the spread of the disease. There will usually be at least one scene in the show or movie where the doctors urge a public official to act on the matter. As part of their plea, they’ll almost always have a fancy computer graphic of the disease spreading across the nation. Like the tentacles of an evil octopus, the graphic shows the disease spreading out from “ground zero” to invade the rest of the country.

As soon as the Kashasha school closed, all of the students went home… and the laughter epidemic spread across the region, almost exactly as it would in one of those maps in a Hollywood movie. Within 10 days of the school’s closure, 217 of the 10,000 people in the village of Nshamba, home to several of the boarding school girls, came down with the “laughing disease”. Several girls that attended a school in Ramashenye but lived near some of the girls from Kashasha infected their own school; within a couple of weeks, 48 of the 154 students there became “infected” and the school was shut down in mid-June. One of the girls that attended the Ramashenye school went back to her home in Kanyangereka when the school closed and promptly “infected” several members of her own family, who in turn “infected” other villagers, who in turn “infected” people from other villages, causing two more schools to close. The “infection” would prove to be tough to eradicate at Kashasha school: after re-opening on May 21st, 57 additional students rapidly became “infected” and the school was shut down again in June.

By the time the “disease” finally ran its course in June 1964, the laughter epidemic had “infected” around 1,000 people and caused the closure of 14 schools in the area. Just like a “real” epidemic, the only effective preventative measure seemed to be quarantining villages yet to be touched by the disease.

Scientists, both then and now, have been able to conclusively rule out any biological or environmental cause of the “disease”. Whatever it was, the epidemic was not caused by a virus or bacteria, or some chemical in the food supply or environment. There is no historical mention of a similar disease in the area, nor is there any word for it in any of the indigenous languages. In fact, scientists were completely puzzled by the initial spread of the “disease” at the Kashasha school. The girls lived in a dormitory-style arrangement there, yet the “disease” didn’t seem to follow any of the known rules of modern pathology. Girls that shared rooms with “infected” students didn’t necessarily become infected themselves. The disease didn’t follow any known pattern of friendship or location.

Once the disease left the school, however, a pattern became clear: adolescent females at mission-run schools were first to be infected. They would then take the disease home to infect their mothers and other female relatives. Young boys appeared to be somewhat susceptible to the disease, however adult men appeared to be completely immune to the epidemic. There is also not a single instance of a “person of stature” in the community – policemen, doctors or schoolteachers, either male or female – becoming infected. Europeans and other Westerners seemed to have immunity, too. In fact, the disease seemed to follow a strict path along tribal and familial lines. If a female relative, a male relative, and a complete stranger of either gender were locked in a room with an “infected” person, the disease would probably infect the female relative, possibly infect the male, and would almost never infect the stranger.

The “Tanganyika Laughter Epidemic”, as the disease is called, has remained a curiosity in medical textbooks for 40 years now. Although many in the medical community are interested in the epidemic, the fact that the disease only caused laughter, sore muscles and extreme irritability in its subjects means that there’s little priority in researching the matter further. “Mass hysteria” seems to be modern medicine’s conclusion about the incident, although that in itself it pretty interesting, as certifiable cases of mass hysteria are vanishingly rare in human history, especially in the modern era. Cases of mass hysteria in Germany and Italy in the wake of the Black Death are well-known (and I’ll write something about that in the next few days), but examples in the modern era are limited to lynchings and a few other incidents. Cases such as the Tanganyika Laughter Epidemic are amazingly rare.

So enjoy your day… but you might want to think twice about telling that joke at the water cooler!