Tick-borne diseases are caused by bacteria transmitted to humans through the bite of an infected tick. Examples of tick-borne diseases include Lyme disease, Ehrlichiosis and Rocky Mountain Spotted Fever (RMSF).

Anyone is susceptible to these diseases, but persons who spend time outdoors in tick-infested environments are at increased risk of exposure. Although ehrlichiosis and RMSF are less likely to occur, infected deer ticks are present in Illinois and can transmit Lyme disease.