Oct.26th: Ukraine detains three suspected Islamic militants
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....