Rocky Mountain spotted fever (RMSF) is caused by the bacterium Rickettsia rickettsii.  Symptoms include headaches, myalgia, and a characteristic rash usually beginning on wrists, ankles, palms and soles. Treatment is usually tetracycline.

Ticks that transmit Rocky Mountain spotted fever include Amblyomma americanum (lone star), Dermacentor variabilis (American dog) and Dermacentor andersoni (wood).