Encephalitis lethargica

Encephalitis lethargica is an atypical form of encephalitis. Also known as "sleeping sickness" or "sleepy sickness" (distinct from tsetse fly-transmitted sleeping sickness), it was first described in 1917 by the neurologist Constantin von Economo and the pathologist Jean-René Cruchet. The disease attacks the brain, leaving some victims in a statue-like condition, speechless and motionless. Between 1915 and 1926, an epidemic of encephalitis lethargica spread around the world. Nearly five million people were affected, a third of whom died in the acute stages. Many of those who survived never returned to their pre-existing "aliveness".