Rickettsioses

Species	Disease	Vector	Clinical Clues
Rickettsiae: Spotted fever group
R. rickettsii	Rocky Mountain spotted fever	Multiple Dermacentor, Amblyomma, and Rhipicephalus ticks	Centripetal rash without eschar in the Americas
R. conorrii	Boutonneuse fever, Mediterranean spotted fever	Rhipicephalus sanguineus ticks	Rash with eschar, predominantly Mediterranean and Black Sea
R. japonica	Oriental spotter fever	Dermacentor, Haemaphysalis, or Ixodes ticks	Rash with eschar, acquired in Asia
R. sibirica mongolitimonae		R. sanguineus	Rash with eschar, acquired in Europe, Africa, or Asia
R. sibirica sibirica		Dermacentor ticks	Rash with eschar, acquired in Asia or southern Russia
R. australis		Ixodes ticks	Vesicular rash with eschar, acquired in Australia
R. slovaca	Tick-borne lymphadenopathy	Dermacentor marginatus	Eschar (often scalp) with regional lymphadenopathy, acquired in Europe
R. africae	African tick-bite fever	Amblyomma hebraeum and Amblyomma variegatum	Vesicular rash with eschar, acquired in Africa or the Caribbean
R. honei		Bothriocroton, Haemaphysalis, Ixodes, or Rhipicephalus ticks	Rash with eschar acquired in Flinders Islands, eastern Australia, Thailand, or Nepal
R. aeschlimanii		Hyalomma or Rhipicephalus ticks	Rash with eschar, acquired in Africa or Europe
R. helvetica		Tick
R. parkeri		A. maculatum ticks	Rash with eschar, acquired in the Americas
R. heilongjianghensis		Dermacentor or Haemaphysalis ticks	Rash with eschar, acquired in Asia
R. raoultii		Dermacentor ticks	Eschar (often scalp) with regional lymphadenopathy, acquired in Europe
R. massiliae		R. sanguineous	Rash with eschar, acquired in Europe, Africa, and the Americas
R. amblyommii		Tick
R. monacensis		Tick
R. philipii strain 364D		Dermcentor occidentalis	Eschar (often scalp) with regional lymphadenopathy, acquired in California
R. felis		Flea	Rash with eschar and flea exposure
R. akari	Rickettsialpox	Liponyssoides sanguineus house mouse mites	Vesicular rash with eschar, worldwide
Rickettiae: Typhus group
R. typhi	Endemic (murine) typhus	Xenopsylla cheopis (rat flea) and Ctenocephalides felis (cat flea)	Centrifugal rash without eschar in the tropics or subtropics, with flea exposure
R. prowazekii	Epidemic (louse-borne) typhus	Pediculus humanus humanus (human body louse)	Centrifugal rash without eschar, with exposure to flying squirrel or other
Rickettsiae: Scrub typhus group
Orientia tsutsugamushi	Scrub typhus	Leptotrombidium mites (chiggers, trombiculid mites)	Rash with eschar, acquired in Asian Pacific, Chile, or Dubai
Anaplasma
A. phagocytophilum	Human granulocytotropic anaplasmosis	Tick
Ehrlichia
E. chaffeensis	Human granulocytotropic anaplasmosis	Amblyomma americanum ticks (the Lone Star tick)
E. ewingii	Human granulocytotropic anaplasmosis	A. americanum and Dermacentor variabilis ticks
E. canis		Tick
Other
Neoehrlichia mikurensis		Tick
Neorickettsia sennetsu		Raw fish
Wolbachia species		Helminths

Management

• First-line for essentially all infections is doxycycline 100 mg po BID, continue for 3 days following resolution of symptoms
• Alternatives include azithromycin and chloramphenicol

Further Reading

• Syndromic classification of rickettsioses: an approach for clinical practice. Int J Infect Dis. 2014;28:126-39. doi: 10.1016/j.ijid.2014.05.025