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Rocky Mountain Spotted Fever (RMSF) is an infection caused by the bite of an infected tick. It affects about 250 to 1,200 people a year in the US and usually occurs from April until September, but it can occur anytime during the year where weather is warm. The mid-Atlantic and southeastern states are most affected. The disease is spread to humans through a bite from an infected tick; it is not spread from one person to another.
In the U.S., the American dog tick (Dermacentor variabilis) and the Rocky Mountain wood tick (Dermacentor andersoni) have been identified as vectors who transmit the RMSF bacteria, as well as the brown dog tick (Rhipicephalus sanguineus).
The following are the most common symptoms of RMSF. However, each person may experience symptoms differently. Symptoms may include:
Death has occurred in untreated cases of RMSF.
Symptoms of RMSF may resemble other conditions or medical problems. Consult a physician for diagnosis.
Diagnosis is based on symptoms and past history of a tick bite. The appearance and character of the rash is important. Skin samples and lab tests (antibody titer, kidney function tests, platelet count, prothrombin time, partial thromboplastin time, urinalysis, red blood cell count) are usually done to rule out other conditions and confirm diagnosis.
Specific treatment for RMSF will be determined by your physician and may include antibiotics and supportive care.
Once a person has RMSF, he/she cannot be re-infected. Some general guidelines for preventing RMSF include: