An outbreak of mass hysteria is reported to have struck three indigenous communities living near the river Coco in northern Nicaragua. A total of 43 people have reportedly fallen ill with what is known locally as grisi siknis ("crazy sickness").
Doctors, anthropologists and sociologists who have studied previous cases of mass hysteria  also known as mass psychogenic illness  have so far failed to come up with any clear explanation for the phenomenon.
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Interesting. It must be terrifying for those afflicted, and those around them.
Cheers,
Scott.