Ehrlichiosis is transmitted to humans by the lone star tick (Ambylomma americanum), found primarily in the southcentral and eastern U.S.
Powassan disease is transmitted by the blacklegged tick (Ixodes scapularis) and the groundhog tick (Ixodes cookei). Cases have been reported primarily from northeastern states and the Great Lakes region.
Rickettsia parkeri rickettsiosis is transmitted to humans by the Gulf Coast tick (Amblyomma maculatum).
Tickborne relapsing fever (TBRF) is transmitted to humans through the bite of infected soft ticks. TBRF has been reported in 15 states: Arizona, California, Colorado, Idaho, Kansas, Montana, Nevada, New Mexico, Ohio, Oklahoma, Oregon, Texas, Utah, Washington, and Wyoming and is associated with sleeping in rustic cabins and vacation homes.
364D rickettsiosis (Rickettsia phillipi, proposed) is transmitted to humans by the Pacific Coast tick (Dermacentor occidentalis ticks). This is a new disease that has been found in California.