Rocky Mountain Spotted Fever: Treatment

Rocky Mountain Spotted Fever (RMSF) is the most severe of all rickettsial diseases. RMSF is caused by Rickettsia Rickettsii. It is characterized by fever, headache, malaise, myalgia (muscle pain), nausea, vomiting, and anorexia for first three days. The patient becomes progressively ill.

RMSFoccurs in all 48 adjoining states in USA (highest prevalence in the south-central and southeastern states) and also in Canada, Mexico, and Central and South America. The infection is transmitted by Dermacentor  andersoni, the Rocky Mountain wood tick, in the western United States and by D. variabilis, the American dog tick, in the eastern two-thirds of the United States and California. It is transmitted by Rhipicephalus sanguineus in Mexico and by Amblyomma cajennense in Central and South America.

Humans usually become infected during tick season (from May to September in the Northern Hemisphere).

Treatment: The drug of choice for the treatment of both adults and children with RMSF is doxycycline except when the patient is allergic to this drug or pregnant. Rocky Mountain Spotted Fever Is very severe disease and prompt treatment with empirical administration of doxycycline should be given as soon as it is diagnosed or suspected strongly. Doxycycline is administered orally at 200 mg/d in two divided doses, in the presence of coma or vomiting, it is given intravenously. For children, up to five courses of doxycycline may be administered with minimal risk of dental staining.

Other drugs include oral tetracycline (25–50 mg/kg per day) in four divided doses. Chloramphenicol can be given if patients are pregnant or allergic to doxycycline.

The antirickettsial drug should be given till the patient has been afebrile (without fever) and improving clinically for 2–3 days. ?-Lactam antibiotics like penicillin, erythromycin, and aminoglycosides have no role in the treatment of RMSF, and sulfa-containing drugs can aggravate this infection.

Prevention of RMSF: tick bites should be avoided as much as possible (although it is not very practicable). Protective clothing and tick repellents can be used; inspection of the body once or twice a day, and removal of ticks before they inoculate rickettsiae reduce the risk of infection. There is no vaccine available for RMSF.