Rocky Mountain Spotted Fever and Spotted Fever Group Rickettsia
Rocky Mountain Spotted Fever (RMSF) and Spotted Fever
group (SPG) are diseases caused by
Rickettsia
bacteria that are transmitted to people through the bite
of an infected tick. RMSF, caused by
Rickettsia
rickettsii, is the most severe and most frequently
reported rickettsial illness in the US. Contrary to its
name, RMSF is rare in the western US; most cases occur
in the Midwestern and southeast US. Only one or two
cases of RMSF are reported each year in California.
Initial signs and symptoms of the disease include sudden
onset of fever, headache, and muscle pain, followed by
development of rash. The disease can be difficult to
diagnose in the early stages, and without prompt and
appropriate treatment, can be fatal.
SFG
Rickettsia can cause fever, headache, and a
small open wound about 1/4 inch in size that turns into
a dark scab (called an eschar). A SFG
Rickettsia
called 364D has been 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.
New and Noteworthy
- CDC Health Advisory:
Severe and Fatal Confirmed Rocky Mountain Spotted Fever among People with Recent Travel to Tecate, Mexico
(12-8-23)
Los Angeles County
Additional Resources
Laboratory Testing
