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Organism
- obligate intracelluar bacteria
- coccobacilli
- giemsa stain
- Cell wall has LPS, peptidoglycan
- Grow in cytoplasmof eukaryotic cells
- Endocytosis -> enter cytoplasm
- Spread using host cytoskeleton
- require Coenzyma A, NAD, ATP
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RMSF: Epidemiology
- Ticks
- Reservoir: rodents, dogs
- Central, mid atlantic states
- young kids, adults 40-65
- Hx of tick bite
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RMSF: Pathogenesis
- Vascular endothelium
- Vasculitis in endothelial cells
- Thrombosis, leakage of RBCs into local area -> rash, petechia
- Vascular lesions throughout body
- LPS mediated infection
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RMSF: Manifestations
- Fever, severe headache, rash (triad) toxicity mental confusion
- rash - 2or 3 days post infection
- Rash - petechia
- Appears at wrists/feet and moves to trunk
- Rash - necrosis, gangrene
- Incubation 2-6 days
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RMSF: Diagnosis
- Serologic tests
- Clinical signs
- Tx: antibiotics in early illness
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Typhus: Epidemiology
- Louse borne
- war, famine, poverty
- Relapses possible - Brills Zissner disease
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Typhus: Manifestations
- Fever, headache, rash 1-2 weeks post bite
- Maculopapular rash on trunks, spreads to limbs
- headache, malaise, myalgia
- Complications: mycarditis, CNS dysfunction, pneumonia
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Typhus: Diagnosis + Tx
- Epidemiology, clinical signs
- Serological tests most reliable/sensitive
- Treat with tetracycline
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Q Fever: Bacteriology/epidemiology
- Differs from other rickettsia in DNA composition
- Zoonoses via inhalation (cattle, sheep, goats)
- Worldwide distribution (grows well in placental tissues)
- Survives in lysosomal vacule
- Slaughterhouse workers
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Q Fever: Manifestations
- 9-20 days post inhalation
- Abrupt onset of fever, chills, headache, dry hacking cough
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Q Fever: Diagnosis/treatment
- High or rising titers of Ab
- Resolve spontaneously, tetracycline to shorten course
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