Table 1.

Classification, distribution, vector, clinical features of some common rickettsial infections

Group	Organism	Disease	Geographic distribution	Vector	Clinical features	Rash	Eschar	Case fatality rate
Scrub typhus group	Orientia tsutsugamushi	Scrub typhus	Asia, Northern Australia, Pacific and Indian Ocean islands	Mite	Fever, headache, myalgia, breathlessness	<50%; maculopapular rash; centrifugal	40–90%	5–25%
	Rickettsia prowazekii	Epidemic typhus (louse-borne typhus)	Worldwide	Louse	Fever, headache, myalgia, rash, severe illness if untreated	20–80%; macular; centrifugal spread	None	6–30%
Typhus group	Rickettsia typhi	Murine typhus or endemic typhus	Worldwide	Flea	Fever, headache, myalgia, rash, milder illness than epidemic typhus	50% maculopapular rash on the trunk	None	0–0.4%
	Rickettsia rickettsii	Rocky Mountain spotted fever	United States, South America	Tick	Fever, headache, malaise, nausea, vomiting, abdominal pain.	>90%; macular; centripetal spread	None	10–25%
Spotted fever group	Rickettsia conorii	Indian tick typhus or Mediterranean spotted fever	Mediterranean countries; Africa; Middle East; India	Tick	Fever, headache, rash, vomiting	>90%; maculopapular rash; centripetal spread from extremities	50%	6–32%
	Rickettsia sibirica	Siberian tick typhus	Northern and Central Asia	Tick	Fever, headache, rash, eschar	>90%, maculopapular, petechial or purpuric	>90%	low
	Rickettsia akari	Rickettsial pox	United States; Russia; Korea; South Africa	Mite	Fever, headache, vesicular rash, photophobia	100%; papulo-vesicular	90%	low
Transitional group	Rickettsia australis	Queensland tick typhus	Queensland tick typhus	Tick	Fever, rash of trunks and limbs	Maculopapular, petechial, or vesicular	50–66%	3%