Sleeping sickness of Kalachi, Kazakhstan

The sleeping sickness of Kalachi, Kazakhstan (with the place or the syndrome sometimes called sleepy hollow) is a conjectured medical condition which causes a person to sleep for days or weeks at a time, together with other symptoms such as hallucinations, nausea, intoxicated behavior, disorientation and memory loss. The phenomenon was only reported in Kalachi and the nearby village of Krasnogorsk. It was first reported in March 2013 and by 2016 had affected about 150 people. The syndrome appeared to be non-communicable. The disease disappeared for some time but re-emerged in 2015, and affected all age groups.

Potential causes of the syndrome were suggested to be carbon monoxide poisoning or contamination of the ground water supply by chemicals used for military operations in the region.