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Typhus fever


There are 3 clinical forms of typhus fever: epidemic, endemic, and scrub typhus; none are to be confused with typoid fever (Salmonella). Epidemic typhus fever is caused by the highly infectious Rickettsia prowazekii and is common in Africa and South America. Epidemic typhus fever has a human reservoir and is transmitted by the human body louse. Endemic typhus, present on most continents but less so in the US, is caused by R. typhi is a zoonotic disease (rodent reservoir) transmitted by fleas, and scrub typhus (Orientia tsutsugamushi) is a zoonotic disease carried in and transmitted by mites. It is most common in Asia and Australia. Rickettsialpox is caused by R. akari and is seen in metropolitan areas (rodent reservoir, mite vector) and includes formation of an eschar at the bite site which resembles cutaneous anthrax. A generalized pox-like rash follows later.


Epidemic typhus
Endemic typhus
Scrub typhus