I’m not definitively ruling any possibility out, at this stage of the story...
There have been a number of ‘suspicious’ (and under-reported) outbreaks of Pneumonic Plague (which is a relatively rare form of the disease, according to the literature) in various places around the world over the past couple of years - most notably, an outbreak in one of the North African nations that was associated with a bio-research facility, earlier this year....
However, the reported details of this story make it a fairly low-probability (but not zero) scenario....
Thank you for posting this information -- I was certain that when I saw the phrase, pneumatic plague, that I'd read about it several times in recent years in regards to bioterror fears.
Incidentally, with the Keyword: UKRAINE, did you see this latest article?
Putin in new Ukraine gas warning http://www.freerepublic.com/focus/f-news/2376051/posts