Rocky Mountain

Rocky Mountain Spotted Fever

Rocky Mountain Spotted Fever (RMSF) is a tick-borne disease caused by the bacterium Rickettsia rickettsii. It is one of the most severe rickettsial infections in the United States and can be fatal if not treated promptly.

Transmission

RMSF is primarily transmitted to humans through the bite of infected ticks. The most common tick vectors are the American dog tick (Dermacentor variabilis), the Rocky Mountain wood tick (Dermacentor andersoni), and the brown dog tick (Rhipicephalus sanguineus).

Symptoms

Symptoms of RMSF typically begin 2 to 14 days after a tick bite and may include:

• Fever
• Headache
• Rash
• Nausea
• Vomiting
• Muscle pain
• Lack of appetite

The characteristic rash usually appears 2 to 5 days after the onset of fever and may include small, flat, pink, non-itchy spots (macules) on the wrists, forearms, and ankles. The rash can spread to the trunk and sometimes to the palms and soles.

Diagnosis

Diagnosis of RMSF is primarily based on clinical signs and symptoms, as well as a history of tick exposure. Laboratory tests, such as serology and polymerase chain reaction (PCR), can help confirm the diagnosis.

Treatment

The first-line treatment for RMSF is the antibiotic doxycycline. It is most effective when started early in the course of the disease. Treatment should not be delayed while waiting for laboratory confirmation.

Prevention

Preventive measures include:

• Avoiding areas with high tick populations
• Using insect repellent containing DEET
• Wearing long sleeves and pants
• Performing tick checks after spending time outdoors

See also

• Tick-borne diseases
• Rickettsial infections
• Doxycycline

External links

• Centers for Disease Control and Prevention - Rocky Mountain Spotted Fever
• World Health Organization - Rickettsial Diseases