This 6-year research program aims to understand the ecological drivers for the geographic variation in Lyme disease risk in eastern North America. More information is available at http://lyme-gradient.tennessee.edu
CNN has a recent article about Powassan virus, spread by blacklegged ticks: http://www.cnn.com/2017/05/03/health/powassan-tick-virus/index.html Here's a map of the locations of Powassan cases in recent years. While the article claims "everyone" is at risk, there is in fact currently no significant risk of this disease for folk in southern states. I know of one report of a patient being treated for Powassan in TN, however I checked with the doctor involved, who says the child contracted the infection on Long Island NY.
Regional variation in tick-borne disease risk deserves more attention than it gets.