Rickettsia typhi

Cell Wall: Gram Negative Shape: Rod
Life Cyle: Obligate Intracellular Parasite
  • R. typhi is transmitted to humans by fleas which have previously taken a blood meal from infected rodents. Inoculation occurs during scratching of skin contaminated by organisms which are shed in the feces of infected fleas.
Clinical Consequences
  • Endemic Typhus can be thought of as a milder form of Epidemic Typhus caused by Rickettsia prowazekii. Disease is characterized by fever and headache roughly 1-2wks following inoculation. Only a minority of patients display a skin rash which manifests as red macules which most often involves the trunk and spreads outwardly sparing the palms and soles of the feet. Disease is self-limited in most cases but can be fatal in a fraction of cases. Notably, Rickettsia prowazekii and R. typhi are so serologically similar that infection with one provides immunity to the other.
  • Doxycycline or chloramphenicol