“The epidemic was characterized by episodes of laughing and crying”
Paging Dr García Márquez. Central African Journal of Medicine, May 1963:
The disease commenced on 30th January, 1962 at a mission-run girls’ middle school at Kashasha village, 25 miles from Bukoba (see map). From that date until the 18th March, 1962, when the school was forced to close down, 95 of the 159 pupils had been affected. Fifty-seven pupils were involved from the 21st May, when the school was re-opened, until it was again shut at the end of June. The spread of the disease to other areas is described below…Most of the victims have been adolescent school girls and school boys, though adult males and females have also been involved. No literate and relatively sophisticated members of society have been attacked.
The patient has had some very recent contact with someone suffering from the disease. The incubation period is from a few hours to a few days. 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.
The examination is notable for the absence of abnormal physical signs. No fever was detected, although some reported that they had had fever after a few days. The only abnormalities found were in the central nervous system. The pupils were frequently more dilated than controls, but always reacted to light. The tendon reflexes in the lower limbs were frequently exaggerated. There were no tremors or fits or losses of consciousness. The neck was not stiff.
Symptoms have lasted from several hours in a few cases up to a maximum of 16 days. During this time the patient is unable to perform her normal duties and is difficult to control.
From Olumide Abimbola in comments, listen to Radiolab on the outbreak.