Rickettsia species
From IDWiki
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!
