Rocky Mountain spotted fever (RMSF) is a severe tick-borne infection caused by the bacterium Rickettsia rickettsii. R. rickettsii is transmitted via infected ticks, most commonly by the species Dermacentor. These 'hard ticks' are typically found in the western, south, and southeast regions of Washington state, however RMSF is uncommon. Activities that increase contact with ticks include hiking or walking in wooded and dense brush areas, meadows, and in areas with weeds and tall grass. Over half of the nationally reported cases occur in the south-Atlantic region of the United States.

Resources for the general public

• Rocky Mountain Spotted Fever facts, CDC

Resources for health care professionals

• Rocky Mountain Spotted Fever in-depth information, CDC

Rocky Mountain Spotted Fever in King County

Purpose of surveillance:

• To detect cases of rare and emerging diseases
  
• To understand the epidemiology of rare and emerging diseases