The sleeping village.. its residents sleep in the streets for days without realizing

The village of Kalechi is located in the north of Kazakhstan, 230 km from the Russian border, and 300 km from the west of the Kazakh capital Astana. Scientists have been baffled by the sudden sleep that occurs to its residents, who sleep while working, driving, or talking with others.
The villagers do not sleep for a few moments or hours, as their slumber lasts from two to six days, and when they wake up they are not aware of what happened to them.
According to the villagers, their suffering with sudden sleep began in 2010, when Lipov Laipuka suddenly fell from her chair while talking to her friends one morning, falling into a deep sleep, from which she only woke up four days later.
Despite efforts to find out the reason behind this, scientists are still unable to explain it.
Viktor Kazachenko, one of them, as he was heading to a neighboring town to accomplish some tasks, but his brain stopped working, and he cannot remember anything else, and it seems that he contracted a sleeping sickness that hits his village Kalchi and did not wake up until after several days.
Many of the villagers suffered from coma-like fainting, and the accompanying symptoms of nausea, headache, and temporary memory loss.
More than 120 residents suffered from it in the first period, and this number constitutes about a quarter of the village's population.
Scientists from neighboring Russia came to find out the reasons for this phenomenon and studied the water, air and food used, but to no avail. It has been proven that the radiation in it does not cause any harm or symptoms such as sudden sleep

Many health and official bodies and scientific institutes have not been able to scientifically determine the reason behind this phenomenon.