Kazakhstan's Health Ministry has pinpointed a possible cause of the mysterious "sleeping illness" that has gripped a small village, causing sufferers to fall asleep for no apparent reason, a slumber that lasts for days at a time.
The baffling illness attracted attention earlier this month, when a 58-year-old Russian national was struck down while visiting the village of Kalachi. She and three Kazakh citizens were airlifted from Kalachi — to which the outbreak of the illness seems to be confined — to the Kazakh capital Astana for treatment last week, Interfax reported at the time, citing the deputy chief of the Esil district, Saule Agymbayeva.
On Sunday, the republic's Health Ministry said a high concentration of certain vapors could be the culprit, Kazakh news site Diapazon.kz reported.
"On the basis of results from the working group, a preliminary conclusion has been made on the possible connection between the symptoms and high concentrations of vapors that have built up during the heating season in basements and poorly ventilated living spaces. Tests conducted in the homes of patients are evidence of this," the ministry said in a statement, according to Diapazon.kz.
The statement was not available on the ministry's official website as of Sunday afternoon.
Tests are still being conducted to rule out any possible radiation from a Soviet-era uranium mine in the area, as well as any possible tainted water in the village, according to Diapazon.kz.
More than 100 people have contracted the disease since the first case was recorded in the spring of 2013, Agymbayeva was quoted by Interfax as saying last week. Doctors and researchers have struggled to come up with any coherent explanation for the mysterious disorder, nicknamed the "sleeping illness" in Russian media.
Those suffering from the illness simply fall asleep at random — on the streets, at work or at school — with nothing able to wake them up. Many then awaken days later, often suffering from memory loss and hallucinations, according to Russian and Kazakh media reports.
Speculation about the roots of the disease abound, with theories including mass psychosis, poisoning, insect bites, alien invasion and the radioactive effects of the abandoned Soviet-era uranium mine in the area.
But researchers have found no trace of any anomalies, poisons or elevated radiation levels around the village, nor any abnormal test results in the sufferers — except for the fact that they just stay asleep, according to media reports.
The official name for the illness is "encephalopathy of unknown etiology" — or, in layman's terms, a brain disorder that nobody can explain.
"We have ruled out infections, we checked blood and spinal fluid, nothing is there," Doctor Kabdrashit Almagambetov from Esil, the capital of the district, told The Siberian Times.
Doctors had initially "categorized it as toxic encephalopathy, but 'toxic' is just a guess here, and encephalopathy is just the title of the set of brain diseases," he was quoted as saying.
The quantity of new cases had previously peaked in late spring and declined in the fall, spurring hopes that colder weather was somehow reining in the spread of the illness. But this year, a new peak began around Dec. 20, putting more than 30 people to sleep, Kazakhstan's Tengri News reported last week.
That is a staggering number, especially given the fact that Kalachi has a population of only 680, according to Interfax.
The village lies not far from Krasnogorsk, a nearly abandoned town of 130 that once housed a population of nearly 6,500, most of whom worked in the local uranium mines.
No cases of the "sleeping illness" have been reported in Krasnogorsk, and workers who toiled at the uranium mines told local media that whatever side effects they might have suffered, inexplicable cases of sleepiness were not among them.
The Russian retiree who is among the latest victims had arrived in Kalachi to visit her uncle — and then promptly fell asleep, Tengri News reported.
Regional authorities have pledged to relocate Kalachi residents to other towns starting early this year, the report said.