The Village that fell asleep: mystery illness that perplexes Kazakh scientists

My first guess would be some sort of chemical poisoning from the mine. Natural uranium is effectively inert in terms of radiation, but it is still a heavy metal and is pretty chemically toxic (in metallic form, I don't know how toxic the ore is). Or some leftover chemical from the mining. Or some gas leaking from underground. Or other radiation sources that are found near uranium (e.g. radon).

But the article says they tested all that. Weird weird weird.

It's not clear from the article that that's a smoking gun. Just prior to that point, we see:

"Elevated levels of radon and carbon monoxide were detected but later ruled out as a cause.", with a link to a Russian page that, Google Translated, seems to actually indicate that CO is still a leading suspect. However, the article immediately goes on to apparently quote from the same Russian page that

"...some of houses (sic) of the affected residents had carbon monoxide levels that were ten times higher than recommended. This... could have caused similar symptoms to the “sleeping sickness”."

So the article itself seems a little sloppy. Beyond that, I wonder what the sickness relationship is between high-CO houses and all inhabitants of them, given that at least one inhabitant per house has experienced the sickness. Is there a correlation? Also, is the social structure of the village such that there are frequent visitations to most or every home? If so, then one might expect to experience the sickness even if one's own house doesn't have high CO.