@Europe and the plague: Hm, valid point there. It probably depends on how contagious the disease is, you know, whether it spreads through fluids, touch or other.

At any rate, dwarves huddling in fortresses tend to be more hygienic and thus simply less affected.

Another point to be considered: since the land is visibly affected, documenting a spreading of the plague - I don't think the black plague did that. So we'd be more into a "contamination-thing". But radiation, for example, doesn't exactly spread... so what is the plague?

I say, we have a question to drive Groam's intellectual elite mad! MAD! ;-)