Rickettsia rickettsii is a bacterial pathogen responsible for Rocky Mountain spotted fever (RMSF), one of the most severe tick-borne diseases in North and South America. RMSF is primarily transmitted to humans through the bites of infected ticks, including the American dog tick (Dermacentor variabilis), the Rocky Mountain wood tick (Dermacentor andersoni), and, in some areas, the brown dog tick (Rhipicephalus sanguineus). The bacteria enter the bloodstream through the tick bite and begin to infect cells lining blood vessels, leading to widespread inflammation.
Rocky Mountain spotted fever typically begins with flu-like symptoms, including fever, headache, muscle pain, and nausea, often within 2 to 14 days after the tick bite. A distinctive rash usually appears a few days later, beginning on the wrists and ankles and spreading to the rest of the body. If left untreated, RMSF can lead to severe complications, including organ failure, vascular damage, and even death, particularly if treatment is delayed.
The preferred treatment for RMSF is the antibiotic doxycycline, which is effective when administered early in the course of the disease. Preventive measures include avoiding tick-prone areas, using insect repellents, wearing protective clothing, and thoroughly checking for ticks after outdoor activities. Rapid diagnosis and prompt treatment are essential to improve outcomes and prevent severe complications associated with RMSF.
