I read a book about infectious diseases in pre-industrial era Finland. It was called "Plague and Prayer" (Rutto ja rukous) and I thought it was super interesting because it combined biological facts with cultural history.
I had no idea we had malaria up here in the north as late as in the 19th century.

I also thought it was quite interesting that while some diseases stigmatized people, some almost did the opposite. Leprosy was considered a disfiguring and terrible disease that was carried by "tainted" people, whereas tuberculosis was regarded as a rather poetic and classy disease that affected artists and other soulful people... It's pretty silly, since both diseases are caused by Myobacteria.
Edit: I noticed there's at least one other topic for books, but I thought it wouldn't hurt to have one only for the very latest book you just happened to read for some reason or the other, regardless of whether you liked it or not.