Medical historian John Waller makes a more psychological diagnosis: stress-induced mass psychosis. Others accuse Sydenham’s chorea, a disorder linked to strep throat and rheumatic fever that causes fluid, dance-like twitches. The cause of these dancing plagues? Some blame ergot, a poisonous mold found on damp rye that ’s related to LSD. It struck 400 people and lasted until September, when it suddenly stopped as mysteriously as it began. The Strasbourg plague, however, was the worst.
No country was immune: Italy, France, Holland, and Germany all suffered. This wasn’t the first time a European village had been plagued by “dancing mania.” The first outbreak had occurred in the seventh century, and cases sporadically struck every few decades. Authorities erected a stage and hired musicians, but the plan backfired: It just encouraged more people to dance. Local physicians ruled out supernatural causes, blaming the “dancing plague” on “hot blood.” They also decided that the best course of action was to encourage the delirium to be danced out. Seldom able to stop for food or rest, some literally danced until they dropped dead of heart attack, stroke, or exhaustion. Hyperventilating and hallucinating, most of the dancers seemed to be totally unconscious. Within a month, 100 people were frantically jigging-and none of them could stop. Troffea danced for three straight days, and by the time she was tied up and hauled away, more than 30 other people had joined in. On July 14, 1518, she stepped onto the streets of Strasbourg, France, and, although there was no music playing, began to boogie uncontrollably. The Middle Ages was no time to start a rave-but that didn’t stop Frau Troffea.