Rocky Mountain Spotted Fever is a tick-borne disease caused rickettsia rickettsii, which is a gram negative obligate intracellular bacteria.
It is endemic in both North and South America.
Symptoms begin 2 to 14 days after the tick bite:
- fever
- headache
- abdominal pain
- myalgia
- rash - appears an average of 3 days after onset of illness - classically petechial
Diagnosis: ELISA. Note blood cultures are of little use as rickettsia rickettsii is poorly cultured, and that PCR of its DNA isn't that useful either as it lacks sensitivity.
Treatment is doxycycline
Prognosis: mortality rate untreated is up to 80%; treated is 3%.
