Increase in tick-borne diseases, U.S.A.
Rates of tick-borne infections in the United States have been increasing dramatically since 2000. See attached graph
(Lyme disease displayed as cases/100,000 to allow fit). Although this phenomenon might reflect changes in human population density and artifacts of reporting and diagnosis, I suspect that these data are related to increasing tick and animal reservoir populations.
Update: Also referenced in ProMED

