Rickettsia prowazekii

From IDWiki
Rickettsia prowazekii


  • Cause of epidemic typhus


Life Cycle

  • Adult louse becomes infected when feeding on a rickettsemic patient
  • The louse poops on another person
  • The person scratches their skin or touches their mucous membrane, innoculating themselves with louse feces


  • Carried by the human body louse, Pediculus humanus corporis
  • Outbreaks are associated with poverty, refugee camps, jails, and cold climate
  • The only non-human reservoir is the flying squirrel (Glaucomys volans) in the US
  • Previously-infected patients may still have latent infection

Clinical Manifestations

  • Incubation period 1 to 2 weeks
  • High fever, severe headache, myalgia, non-producive cough, delirium
  • Dull, red rash starting on the trunk and spreading peripherally
    • Spares palms and soles
    • Rash not always present
  • Delirium, hemorrhagic rash
  • In its severe form, can progress to pulmonary edema, encephalitis, shock, and death

Brill-Zinsser disease (BZD)

  • Reactivation or recrudescence of dormant typhus years after the initial infection
  • Often in the context of malnutrition, chronic illness, and poor hygeine
  • Rash may be evanescent or absent, and resolves faster


  • Four-fold rise in indirect immunofluorescence assay for IgG
  • PCR may be useful during acute illness


  • Need to treat even without confirmed diagnosis
  • Doxycycline 100 mg po bid for 7 to 10 days, until afebrile for 24 to 48 hours
  • Chloramphenicol is the alternative
  • Wash clothing to prevent outbreaks