Rickettsia: Difference between revisions

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Latest revision as of 14:57, 11 November 2025

Background

A genus of obligate mostly-tick-borne intracellular Gram-negative bacteria

Species	Disease	Vector	Distribution
Typhus Group
Rickettsia prowazekii	epidemic typhus	body louse
Rickettsia typhi	murine/endemic typhus	rat/cat fleas
Spotted Fever Group
Rickettsia rickettsii	Rocky Mountain spotted fever (RMSF)	Dermacentor variabilis ticks	eastern, central, and Pacific coast of US
		Dermacentor andersoni ticks	western US
		Rhipicephalus sanguineus ticks	Mexico and southern US
		Amblyomma cajennense ticks	Central and South America
Rickettsia parkeri	American tick-borne fever	Amblyommma maculatum ticks	southern US
Rickettsia parkeri	American tick-borne fever	Amblyomma triste ticks	Uruguay, Brazil, and Argentina
Rickettsia conorii	Mediterranean spotted fever	Rhipicephalus sanguineus ticks
Rickettsia japonica	Oriental spotter fever
Rickettsia heilongiangensis	Far Eastern spotted fever		eastern Russia, Thailand, and China
Rickettsia africae	African tick bite fever	Amblyomma ticks
Rickettsia slovaca	tick-borne lymphadenopathy (TIBOLA)	Dermacentor marginatus ticks
Transitional Group
Rickettsia akari	rickettsialpox	Liponyssoides sanguineus house mouse mites
Rickettsia australis	North Queensland tick typhus
Rickettsia felis	flea-borne spotted fever
Ancestral Group
Rickettsia bellii
Rickettsia canadensis
Other Rickettsiae
Orientia tsutsugamushi	scrub typhus	chiggers
Ehrlichia species	human monocytotropic ehrlichiosis	Amblyomma americanum and other ticks
Anaplasma species	human granulocytic anaplasmosis	Ixodes scapularis and Ixodes pacificus ticks
Neorickettsia		helminths
Wolbachia		helminths and arthropods

Management

Spotted Fever Group

Doxycycline 100 mg po bid for 7 to 10 days
- Alternatively: tetracycline 2 g/day or chloramphenicol 2 g/d
- Alternatively: ciprofloxacin 750 mg po bid for 5 to 7 days
  - But no good evidence for this
Can use doxycycline safely for these duration in children <8 years, and is strongly indicated for rickettsioses
May use azithromycin or clarithromycin in pregnant women
Avoid TMP-SMX, which appears to worsen severity of disease!

@@ Line 1: / Line 1: @@
 ==Background==
-===Microbiology===
 * A genus of obligate mostly-tick-borne intracellular Gram-negative bacteria
+{| class="wikitable"
-===Typhus Group===
+! Species
-* ''[[R. prowazekii]]'': causes epidemic typhus, transmitted by the body louse
+! Disease
-* ''[[R. typhi]]'': causes murine/endemic typhus, transmitted by rat/cat fleas
+! Vector
+! Distribution
-===Spotted Fever Group===
+|-
-* ''[[R. rickettsii]]'': causes Rocky Mountain spotted fever (RMSF)
+! colspan=4 | Typhus Group
-* ''[[R. parkeri]]'': carried by ''A. maculatum'' in the southern US and ''A. triste'' in Uruguay, Brazil, and Argentina
+|-
-* ''[[R. conorii]]'': causes boutonneuse fever
+| [[Rickettsia prowazekii]]|| epidemic typhus || body louse ||
-* ''[[R. japonica]]'': causes oriental spotter fever
+|-
-* ''[[R. heilongiangensis]]'': causes Far Eastern spotted fever in eastern Russia, Thailand, and China
+| [[Rickettsia typhi]]|| murine/endemic typhus || rat/cat fleas ||
-* ''[[R. africae]]'': causes African tick bite fever
+|-
-* ''[[R. slovaca]]'': causes tick-borne lymphadenopathy (TIBOLA)
+! colspan=4 | Spotted Fever Group
-** Transmitted by ''Dermacentor marginatus'' ticks
+|-
+| rowspan=4 | [[Rickettsia rickettsii]]
-===Transitional Group===
+| rowspan=4 | Rocky Mountain spotted fever (RMSF)
-* ''[[R. akari]]'': causes rickettsialpox, transmitted by the house mouse mite, ''Liponyssoides sanguineus''
+| [[Dermacentor variabilis]] ticks || eastern, central, and Pacific coast of US
-* ''[[R. australis]]'': causes North Queensland tick typhus
+|-
-* ''[[R. felis]]'': causes flea-borne spotted fever
+| [[Dermacentor andersoni]] ticks || western US
+|-
-=== Ancestral Group ===
+| [[Rhipicephalus sanguineus]] ticks || Mexico and southern US
-* ''[[Rickettsia bellii]]''
+|-
-* ''[[Rickettsia canadensis]]''
+| [[Amblyomma cajennense]] ticks || Central and South America
+|-
-===Other Rickettsiae===
+| rowspan=2 | [[Rickettsia parkeri]]
-* ''[[Orientia tsutsugamushi]]'': causes scrub typhus, transmitted by chiggers
+| rowspan=2 | American tick-borne fever
-* ''[[Ehrlichia]]'': transmitted by ticks
+| [[Amblyommma maculatum]] ticks || southern US
-* ''[[Anaplasma]]'': transmitted by ticks
+|-
-* ''[[Neorickettsia]]'': transmitted by helminths
+| [[Amblyomma triste]] ticks || Uruguay, Brazil, and Argentina
-* ''[[Wolbachia]]'': transmitted by helminths and arthropods
+|-
+| [[Rickettsia conorii]]|| Mediterranean spotted fever || [[Rhipicephalus sanguineus]] ticks ||
+|-
+| [[Rickettsia japonica]]|| Oriental spotter fever || ||
+|-
+| [[Rickettsia heilongiangensis]]|| Far Eastern spotted fever || || eastern Russia, Thailand, and China
+|-
+| [[Rickettsia africae]]|| African tick bite fever || [[Amblyomma]] ticks ||
+|-
+| [[Rickettsia slovaca]]|| tick-borne lymphadenopathy (TIBOLA) || [[Dermacentor marginatus]] ticks ||
+|-
+! colspan=4 | Transitional Group
+|-
+| [[Rickettsia akari]]|| rickettsialpox || [[Liponyssoides sanguineus]] house mouse mites ||
+|-
+| [[Rickettsia australis]]|| North Queensland tick typhus || ||
+|-
+| [[Rickettsia felis]]|| flea-borne spotted fever || ||
+|-
+! colspan=4 | Ancestral Group
+|-
+| [[Rickettsia bellii]]|| || ||
+|-
+| [[Rickettsia canadensis]]|| || ||
+|-
+! colspan=4 | Other Rickettsiae
+|-
+| [[Orientia tsutsugamushi]]|| scrub typhus || chiggers ||
+|-
+| ''[[Ehrlichia]]'' species || human monocytotropic ehrlichiosis || [[Amblyomma americanum]] and other ticks ||
+|-
+| [[Anaplasma]] species || human granulocytic anaplasmosis ||  [[Ixodes scapularis]] and [[Ixodes pacificus]] ticks ||
+|-
+| [[Neorickettsia]]|| || helminths ||
+|-
+| [[Wolbachia]]|| || helminths and arthropods ||
+|}
 ==Management==
@@ Line 44: / Line 80: @@
-{{DISPLAYTITLE:''Rickettsia'' species}}
+{{DISPLAYTITLE:''Rickettsia''}}
 [[Category:Rickettsioses]]