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For further information, see CMDT Part 32-12: Spotted Fevers
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Caused by Rickettsia rickettsii, a parasite of ticks, transmitted by tick bites
Most cases occur in only five states: North Carolina, South Carolina, Tennessee, Oklahoma, and Arkansas
Most cases occur in late spring and summer
Typical incubation period is 2–14 days (median, 7 days)
Mortality rate is over 70% in untreated patients
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Initial symptoms include fevers, chills, headache, nausea and vomiting
Cough and pneumonitis often occur early in the disease
In more severe cases, delirium, lethargy, seizures, stupor, and coma may also appear
Rash (not always found) begins as a faint macule that progresses to large maculopapules and often petechiae
Rash begins on the wrists and ankles, characteristically involves palms and soles, and spreads to arms, legs, and trunk
Splenomegaly, hepatomegaly, jaundice, myocarditis (which may mimic an acute coronary syndrome), adrenal hemorrhage, polyarticular arthritis, or uremia are occasionally present
About 3–5% of recognized cases in the United States are fatal
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Doxycycline (100 mg orally twice daily for 4–10 days) or chloramphenicol (50–100 mg/kg/day in four divided doses, orally or intravenously for 4–10 days) are usually highly effective
Prevention: protective clothing and avoiding tick bites