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ALL / Infectious Diseases
Typhus
Typhus
Typhus is a group of rickettsial diseases transmitted between hosts by arthropods. Examples include- endemic typhus
- caused by Rickettsia typhi
- reservoir/vector: fleas on rats
- occurs throughout the world, typically in warm costal regions
- relative bradycardia
- epidemic typhus
- caused by Rickettsia prowazekii
- reservoir/vector: body louse
- more common in central and eastern Africa, central and South America
- scrub typhus
- caused by Orientia tsutsugamushi
- reservoir: small rodents
- vector: transmitted by the bite of larval trombiculid mites (chiggers)
- more common in Asia
- black eschar at site of original inoculation
- relative bradycardia despite fever
- spotted fever
- caused by Rickettsia spotted fever group
- spread by ticks
- examples include Rocky Mountain spotted fever
Common features
- fever, headache, malaise
- rash
- typically maculopapular
- begins on the trunk and spreads to the extremities
- later complications
- meningoencephalitis
Investigation
- rickettsial serology (immunofluorescence assay)
- antibodies may be negative early in disease
- rising titre on convalescent sample confirms diagnosis
- PCR may be useful in early infection
Management
- doxycycline
+PassMedicine Notes
Typhus is a group of rickettsial diseases transmitted between hosts by arthropods. Examples include
- endemic typhus
- caused by Rickettsia typhi
- reservoir/vector: fleas on rats
- occurs throughout the world, typically in warm costal regions
- relative bradycardia
- epidemic typhus
- caused by Rickettsia prowazekii
- reservoir/vector: body louse
- more common in central and eastern Africa, central and South America
- scrub typhus
- caused by Orientia tsutsugamushi
- reservoir: small rodents
- vector: transmitted by the bite of larval trombiculid mites (chiggers)
- more common in Asia
- black eschar at site of original inoculation
- relative bradycardia despite fever
- spotted fever
- caused by Rickettsia spotted fever group
- spread by ticks
- examples include Rocky Mountain spotted fever
- fever, headache, malaise
- rash
- typically maculopapular
- begins on the trunk and spreads to the extremities
- later complications
- meningoencephalitis
- rickettsial serology (immunofluorescence assay)
- antibodies may be negative early in disease
- rising titre on convalescent sample confirms diagnosis
- PCR may be useful in early infection
- doxycycline