It was 1962, the girls wouldn’t stop laughing and nobody knew why.

And even stranger, the laughter was spreading. Like a virus.

This was at an all-girls school in Kashasha, Tanzania. A few students had started laughing and they couldn’t stop. And this inexplicable behavior spread from girl to girl until 95 of the 159 students were affected. After 6 weeks the school had to close because of it. But that didn’t stop the laughter.

It had already spread to a neighboring village, Nshamba. 217 more girls afflicted. And then it spread to Bukoba, “infecting” 48 more girls.

All told this “outbreak” lasted 18 months, closed 14 schools, and affected over 1000 children.

Sound crazy? It’s true. While certainly uncommon, this kind of thing is not unheard of. During the Middle Ages there were outbreaks of “choreomania” – uncontrollable, infectious dancing that spread throughout Europe sometimes affecting tens of thousands of…