Spotted Fever Group Rickettsia and Rocky Mountain Spotted Fever
Spotted Fever Group (SFG) Rickettsia and Rocky Mountain Spotted Fever (RMSF) are related infectious diseases that are transmitted to people through the bite of a tick. SFG Rickettsia can cause a fever, headache and a small open wound about ¼ inch in size that turns into a dark scab (called an eschar). A SFG Rickettsia called 364D has been recently identified from a small number of people in northern California and has been found in the Pacific Coast tick in eight counties, in both northern and southern California.
Typical symptoms of RMSF include fever, muscle aches, and a rash that often begins on the arms and legs and spreads to the rest of the body. RMSF is treatable with antibiotics. Contrary to its name, RMSF is rare in the western United States; most cases occur in the Midwest and southeastern U.S. Only one or two cases of RMSF are reported each year in California.