Rickettsiae

obligate intracellular organisms

Rickettsial triad

Headache + Fever + Rash

RMSF

Rickettsia rickettsii

Endemic typhus

Rat fleas

Rickettsia typhi

Epidemic typhus

Human body lice

Rickettsia prowazekii

starts centrally and spreads outwards

Weil-Felix reaction

Rickettsial infections have antibodies against Rickettsia

Those anti-rickettsial antibodies cross-react and agglutinate --> positive Weil-Felix reaction

Some serotypes of (non-motile) Proteus are also positive

Coxiella = negative Weil-Felix reaction

Tx

Doxycycline for all Rickettsial infections