I plan to go a little more in-depth into that detail later on, because there are a lot of factors that go into it.

I think it was probably influenced a lot by the novel Lord Foul's Bane. The book itself was kind of unpalatable, but those first few chapters were intense in their brutal account of the protagonist's experiences after contracting Hansen's disease (aka, leprosy), and the depression that kind of isolation can cause. Even in the 21st century (or 20th, in the book), there is a strong stigma attached to the disease, enough so that his wife left him, taking their kid, and some anonymous person in his community went so far as to start paying his utility bills so he wouldn't have to enter town.