Medical Microbiology

332 4 BacteriaasHumanPathogens

Table4. 13 PathogensandClinicalPicturesoftheRickettsiosesandofQFever

Pathogen Vector/host Disease Clinicalpicture

Typhusgroup

Rickettsia

prowazekii

Body

louse/humans

Epidemictyphus

(ET)

Incubation 10 – 14 days;high

fever; 4 – 7 daysafteronset

maculousexanthem;lethalityas

highas 20 %ifuntreated

Brill-Zinsser

disease

Endogenoussecondaryinfection

byrickettsiaepersistinginthe

RES;resultsfromreductionof

immuneprotection;milder

symptomsthanET

R.typhi Ratflea/rat Murinetyphus SymptomsasinET,butmilder

Spottedfevergroup

R.rickettsii Hardtick/

rodents,tick

RockyMountain

spottedfever

(RMSF)

Incubation: 6 – 7 days;continuing

fever 2 – 3 weeks;maculopapu-

lousexanthemonextremities

R.conori Hardtick/

rodents

Fie`vrebouton-

neuse(Mediterra-

neanfever)

SymptomsasinRMSF,necrotic

lesionssometimesdevelopat

bitelocus

R.sibirica Hardtick/

rodents

NorthAsiantick

fever

SymptomsasinRMSF,necrotic

lesionssometimesdevelopat

bitelocus

R.akari Mite/rodents Rickettsialpox Fever;exanthemresemblesthat

ofchickenpox

Tsutsugamushifever

Orientiatsu-

tsugamushi

Mitelarvae/

rodents

Japanesespotted

fever

SymptomssimilartoETplus

locallesionatbitelocusand

lymphadenitis

Qfever(Queryfever)

Coxiella

burnetii

Dust/sheep,

cattle,goats,

rodents

Qfever Incubation 2 – 3 weeks;interstitial

pneumonia(clinicalpictureoften

atypical);chronicQfever(endo-

carditis)withonsetyearsafter

primaryinfection,poorprog-

nosis

4

Kayser, Medical Microbiology © 2005 Thieme