Rickettsia rickettsii
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Rickettsia rickettsii
- Characteristics
- Gram negative
- Obligate intracellular
- Transmission
- Vector is tick
- Specifically by ticks of the Dermacentor family
- Seen after exposure to infected dogs or outdoors settings
- Occurs primarily in the South Atlantic states, especially North Carolina
- Cases occur in western US, but is rarer
- Contrast w/ Lyme disease caused by Borelia burgdorferi, a tick-mediated disease which occurs in Northeastern US
- Vector is tick
- Presentation: Rocky Mountain spotted fever
- Classic triad of headache, fever, rash
- Rash spreads inwards (centripetally)
- Starts at wrists and ankles (including palms and soles), moves to trunk
- Palm + soles rash is also seen in secondary syphilis and Coxsackievirus A infection
- Contrast w/ typhus (Rickettsia typhi + prowazekii), which present with rash that spares the palms and soles
- Treatment
- Doxycycline
- Caution during pregnancy; alternative is chloramphenicol
- Doxycycline