Rickettsia: Difference between revisions

Revision as of 18:42, 30 June 2020

Background

Microbiology

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

Typhus Group

R. prowazekii: causes epidemic typhus, transmitted by the body louse
R. typhi: causes murine/endemic typhus, transmitted by rat/cat fleas

Spotted Fever Group

R. rickettsii: causes Rocky Mountain spotted fever (RMSF)
R. parkeri: carried by A. maculatum in the southern US and A. triste in Uruguay, Brazil, and Argentina
R. conorrii: causes boutonneuse fever
R. japonica: causes oriental spotter fever
R. heilongiangensis: causes Far Eastern spotted fever in eastern Russia, Thailand, and China
R. africae: causes African tick bite fever
R. slovaca: causes tick-borne lymphadenopathy (TIBOLA)
- Transmitted by Dermacentor marginatus ticks

Transitional Group

R. akari: causes rickettsialpox, transmitted by the house mouse mite, Liponyssoides sanguineus
R. australis: causes North Queensland tick typhus
R. felis: causes flea-borne spotted fever

Ancestral Group

Other Rickettsiae

Orientia tsutsugamushi: causes scrub typhus, transmitted by chiggers
Ehrlichia: transmitted by ticks
Anaplasma: transmitted by ticks
Neorickettsia: transmitted by helminths
Wolbachia: transmitted by 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 3: / Line 3: @@
 * A genus of obligate mostly-tick-borne intracellular Gram-negative bacteria
-==Typhus Group==
+===Typhus Group===
 * ''[[R. prowazekii]]'': causes epidemic typhus, transmitted by the body louse
 * ''[[R. typhi]]'': causes murine/endemic typhus, transmitted by rat/cat fleas
-==Spotted Fever Group==
+===Spotted Fever Group===
 * ''[[R. rickettsii]]'': causes Rocky Mountain spotted fever (RMSF)
 * ''[[R. parkeri]]'': carried by ''A. maculatum'' in the southern US and ''A. triste'' in Uruguay, Brazil, and Argentina
@@ Line 17: / Line 17: @@
 ** Transmitted by ''Dermacentor marginatus'' ticks
-==Transitional Group==
+===Transitional Group===
 * ''[[R. akari]]'': causes rickettsialpox, transmitted by the house mouse mite, ''Liponyssoides sanguineus''
 * ''[[R. australis]]'': causes North Queensland tick typhus
 * ''[[R. felis]]'': causes flea-borne spotted fever
-===Management===
+=== Ancestral Group ===
-* [[Is treated by::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 &lt;8 years, and is strongly indicated for rickettsioses
-* May use [[azithromycin]] or [[clarithromyci]]n in pregnant women
-* ''Avoid'' [[TMP-SMX]], which appears to ''worsen'' severity of disease!
-== Ancestral Group ==
 * ''[[Rickettsia bellii]]''
 * ''[[Rickettsia canadensis]]''
-== Other Rickettsiae ==
+===Other Rickettsiae===
 * ''[[Orientia tsutsugamushi]]'': causes scrub typhus, transmitted by chiggers
 * ''[[Ehrlichia]]'': transmitted by ticks
@@ Line 41: / Line 32: @@
 * ''[[Neorickettsia]]'': transmitted by helminths
 * ''[[Wolbachia]]'': transmitted by helminths and arthropods
+==Management==
+===Spotted Fever Group===
+* [[Is treated by::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 &lt;8 years, and is strongly indicated for rickettsioses
+* May use [[azithromycin]] or [[clarithromyci]]n in pregnant women
+* ''Avoid'' [[TMP-SMX]], which appears to ''worsen'' severity of disease!
 {{DISPLAYTITLE:''Rickettsia'' species}}