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Rickettsiae = obligate intracellular bacterial parasite

Incubation: 2-23 days


Carried by host anthropods


Widespread vasculitis and endothelial proliferation may affect any organ

Thrombotic occlusion may lead to gangrene

Clinical features

Typhus clinical features

Rickettsial rash
Rickettsial rash


TypeBacteriaVectorEpidemiology Notes
Epidemic typhusR. prowazekiiLice on humansoften causes epidemics following wars and natural disasters i.e. Caused hundreds of deaths in Nazi concentration camps 


this is usually the condition meant when just talking about “typhus”


Rash begins in trunkal region, the spreads to peripheries.

Murine / endemic typhusR.typhiFleas on ratsMore prevalent in warm coastal regions most commonly, southern California, Texas and Hawaii. 

Generally causes flu-like symptoms(often confused with flu)

Rocky mountain spotted typhusR.rickettsiiTick-borneEndemic in rocky mountains and SE USARash begins peripherally as macules and then becomes petechial/


Scrub typhusOrientia tsutsugamushiHarvest mites on humans or rodentsMost common is SE AsiaSigns include sudden deafness and lung signs



Should be considered in all travellers form endemic areas with apparent septicaemia but negative blood cultures

  • Rise in antibody titre in paired sera is diagnostic
  • Skin biopsy may be diagnostic in rocky mountain spotted fever.


Doxycycline or chloramphenicol


Vaccine available


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Dr Tom Leach

Dr Tom Leach MBChB DCH EMCert(ACEM) FRACGP currently works as a GP and an Emergency Department CMO in Australia. He is also a Clinical Associate Lecturer at the Australian National University, and is studying for a Masters of Sports Medicine at the University of Queensland. After graduating from his medical degree at the University of Manchester in 2011, Tom completed his Foundation Training at Bolton Royal Hospital, before moving to Australia in 2013. He started almostadoctor whilst a third year medical student in 2009. Read full bio

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