Annual incidence (per million persons) for Rocky Mountain Spotted Fever in the United States, 2018

Although RMSF cases have been reported throughout most of the contiguous United States, five states (North Carolina, Oklahoma, Arkansas, Tennessee, and Missouri) account for over 60% of RMSF cases. The primary tick that transmits Rickettsia rickettsii in these states is the American dog tick (Dermacentor variabilis, Dermacentor andersoni).