Kalachi sleeping sickness

The Kalachi sleeping sickness (Russian: Сонная болезнь Калачей, Kazakh: Калачи ұйқы ауруы) was an outbreak of sudden, uncontrollable sleep that affected residents of the village of Kalachi and the nearby settlement of Krasnogorskiy in the Akmola Region of northern Kazakhstan between approximately 2012 and 2016. Over 140 people, roughly a quarter of the local population, experienced episodes of prolonged sleep lasting from hours to days, accompanied by hallucinations, memory loss, dizziness, and headaches. The illness was diagnosed as "encephalopathy of unknown etiology" and was found to be non-communicable.

Kalachi sleeping sickness

Date	c. 2010/2012 – 2016
Location	Kalachi and Krasnogorskiy, Akmola Region, Kazakhstan
Type	Medical mystery / environmental health event
Cause	Disputed; officially attributed to carbon monoxide and hydrocarbon emissions from a disused uranium mine
Deaths	0
Injuries	Over 140 people affected

The cause of the outbreak remains disputed. In July 2015, the Kazakh government announced that elevated levels of carbon monoxide and hydrocarbons, emanating from an abandoned Soviet-era uranium mine near the villages, were reducing oxygen in the air and producing the syndrome. A competing theory, advanced by epidemiologists from Nazarbayev University in 2020, proposed that chemical contaminants had leached into the village's common water supply from buried waste in the mine shafts. After the outbreak subsided in 2016, the government resettled most of Kalachi's inhabitants, declaring the village unviable.

Background

Kalachi is a village in the Esil District of the Akmola Region, approximately 500 kilometres west of Astana. At the time of the outbreak, it had a population of roughly 600 to 680, mostly ethnic Russians and Germans. The neighboring settlement of Krasnogorskiy (also called Krasnogorsk) had been a mining town of 6,500 residents during the Soviet period, when uranium ore was extracted from nearby shafts between the 1960s and the early 1990s. After the mine closed following the dissolution of the Soviet Union, Krasnogorskiy's population dwindled to around 130, and its apartment blocks were left derelict.

Outbreak

Sporadic cases of unusual sleepiness were reported in Kalachi as early as 2010 or 2011, but the first major cluster occurred in March 2013, when around ten people suddenly fell asleep and were hospitalized. Further waves followed, typically in the spring and autumn months. By early 2015, over 100 people had been affected, and the total would eventually exceed 140 across both settlements. Some individuals suffered multiple episodes.

Viktor Kazachenko, a Kalachi resident, fell asleep while driving his motorcycle with his wife riding pillion on 28 August 2014; he regained consciousness in hospital on 2 September with no memory of the intervening days. His was one of the more dramatic cases, but the pattern was similar throughout the village: people would suddenly feel drowsy, lose the ability to stay awake, and fall into a deep sleep from which they were difficult to rouse. Some episodes lasted up to six days.

The illness affected all age groups. Children fell asleep at school. Some children, including two named in press reports as Rudolf Boyarinos and Misha Plyukhin, reported hallucinations of winged horses, snakes in their beds, and worms eating their hands. Even animals were affected: one resident, Yelena Zhavoronkova, told reporters that her cat Marquis had become agitated on a Friday night, attacking walls, furniture, and the family dog, before falling asleep and snoring like a human until Saturday lunchtime, unresponsive to any stimulus.

Upon waking, affected individuals experienced memory loss, disorientation, grogginess, weakness, headaches, and in some cases dizziness and nausea. Doctors diagnosed the condition as "encephalopathy of unknown etiology", a catch-all term for brain disorders with no identified cause.

Investigation

The outbreak attracted national attention and was placed on what officials described as the "personal radar" of President Nursultan Nazarbayev. An interdepartmental working group was created at the instruction of the prime minister, involving the ministries of health, energy, and interior, as well as the national security committee. Over 20,000 laboratory and clinical tests were conducted on air, soil, water, food, animals, building materials, and the residents themselves.

Ruled-out hypotheses

The proximity of the abandoned uranium mine made radiation an early suspect, but gamma-background measurements in Kalachi recorded 0.08 to 0.14 μSv/h, well below the permissible limit of 0.30 μSv/h. Some homes showed elevated radon levels (226 to 567 Bq/m³, against a norm of 200 Bq/m³), but specialists concluded this was insufficient to explain the acute symptoms.

Other hypotheses were considered and discarded. Tests ruled out viral and bacterial causes, as the illness was non-communicable and patients had no fever. Counterfeit alcohol was an early suspicion, but some affected individuals did not drink alcohol at all. One somnologist suggested mass psychosis comparable to the "Bin Laden itch", a psychosomatic rash that had affected children in the United States in 2002, but this failed to account for the physical symptoms and the involvement of animals. Professor Leonid Rikhvanov of Tomsk Polytechnic University proposed that local farmers' use of insecticides, particularly dust, might be responsible, but this was not confirmed.

Carbon monoxide hypothesis

In June 2015, Sergey Lukashenko, deputy director general of Kazakhstan's National Nuclear Centre, announced preliminary findings. His team had detected elevated carbon monoxide (CO) and hydrocarbon (CH) concentrations in the village, combined with reduced oxygen. Lukashenko explained that each of the three factors was individually within normal limits, but their combination produced what he called a "classic synergy effect": periodic inhalation of air with low oxygen and high CO and CH levels induced the sleep episodes.

He proposed that the abandoned mine, which had flooded after its closure, was producing carbon monoxide through the decomposition of wooden structures (fixtures, flooring, and supports) left underground. The gas then leaked to the surface, particularly under certain weather conditions.

On 15 July 2015, Deputy Prime Minister Berdibek Saparbaev announced that the government considered the mystery solved: "The uranium mines were closed at some point, and at times a concentration of carbon monoxide occurs there. The oxygen in the air is reduced accordingly, which was the real reason for the sleeping sickness in these villages."

The carbon monoxide theory faced criticism. Earlier that year, the health ministry had reported that blood tests of affected residents showed no evidence of CO poisoning. Claude Piantadosi, a pulmonologist at Duke University Medical Center, told Wired that while CO symptoms were consistent with the reported effects, "the symptoms are not specific, and that's the problem." Robert Ferriter, a mine safety specialist at the Colorado School of Mines, questioned how enough gas could escape from the mine and travel to open-air locations at sufficient concentration to knock someone off a motorcycle or cause sleep at a market stall.

Water contamination hypothesis

In 2020, a team led by epidemiologist Byron Crape of Nazarbayev University published an alternative theory. After interviewing over 200 present and former villagers, Crape's team found that all Kalachi residents purchased drinking water from a single underground pump operated by a local resident. Animals, which generally drank river water, were not affected, with the notable exception of one cat that may have been given the pumped water.

Crape proposed that chemical waste, possibly of military origin, had been disposed of in barrels within the mine shafts during the Soviet era. Over decades, the barrels corroded, leaking chemicals into the groundwater that fed the village's pump. His team's analysis also found that illness episodes did not correlate with wind direction, as would be expected if the cause were airborne gas from the mine.

The team ruled out bacterial meningitis, genetic diseases, and carbon monoxide as primary causes. They noted that people fell ill more often during cold seasons, when water consumption from the pump was higher and ventilation in homes was poorer.

Crape acknowledged that confirming or refuting the hypothesis would require entering the mine shafts to take samples, but the abandoned tunnels were too dangerous to enter. He proposed building a specialized drone to navigate the mine and collect samples.

Resettlement and aftermath

Faced with a health hazard that could not be definitively explained or remediated, the government opted to relocate the villages. In January 2015, the governor of the Akmola Region announced a voluntary resettlement plan to move all of Kalachi's roughly 680 residents, initially targeting completion by May 2015. By July 2015, 68 of 223 families had been relocated, with eventual plans to move the rest.

Residents were offered housing in the district center of Esil and in Derzhavinsk. The resettlement was described as voluntary, but some residents resisted, unwilling to abandon homes and gardens they had occupied for decades. Those who stayed expressed frustration with the size and conditions of the replacement housing, which in some cases was rented rather than owned.

The sleeping sickness ceased as abruptly as it had begun. By 2016, no new cases had been reported for months. The village of Kalachi was largely depopulated: abandoned houses, overgrown gardens, and a population reduced to a fraction of its former size.

As of 2020, roughly a third of the original population remained in Kalachi, demanding that the government fulfill outstanding compensation commitments. Some former residents continued to report persistent health problems, including headaches and elevated blood pressure, years after their episodes.

See also

• Encephalitis lethargica, a different condition also known as "sleeping sickness"
• Dancing plague of 1518
• Mass psychogenic illness