Rickettsia parkeri rickettsiosis, caused by infection with R. parkeri, is spread by the Gulf Coast tick, Amblyomma maculatum pdf icon[PDF – 1 page], which is found in the southeastern United States.

Pacific Coast tick fever is caused by the bacteria R. philipii (known previously as Rickettsia sp. 364D). Pacific Coast tick fever is spread by the bite of infected Pacific Coast ticks, Dermacentor occidentalis, which can be found along the western coastline in California, Oregon, and Washington.

Rickettsialpox is caused by R. akari. Unlike the other spotted fevers described here, R. akari is spread through the bite of infected mouse mites (Liponyssoides sanguineus). Cases occur occasionally throughout the United States, and are most often reported out of the northeastern United States, particularly New York City.