Term
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Definition
- gram- obligate intracellular parasites
- phospholipase
- important for their life cycle
- cause release of factors that produce rash and other pathology
- can polymerize actin (like Listeria and Shigella)
- require host nucleotide cofactors (NAD, CoA) --> leak vital substances when removed from host cells
- most have animal reservoirs and arthropod vectors
- multiply in cytoplasm
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Term
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Definition
- morphologically similar but exhibit pleomorphism
- obligate intracellular parasites
- grow in lymphocytic vesicles
- Erlichiae grow in phagosomes called morulae
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Term
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Definition
- Epidemic typhus
- headache, malaise, mild to high fever in 2-3 days
- rash in 4-7 days: trunk→ extremities
- infect endothelium - thrombosis, hemorrhage, plasma leakage, hemoconcentration, shock (high mortality)
- human body louse vector
- Brill-Zinssner disease - usually mild relapse
- typhus vaccine lessons disease but does not prevent it
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Term
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Definition
- Endemic or murine typhus
- fever, headache, vascular lesions, possible rash, renal involvement
- rat flea vector
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Term
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Definition
- scrub typhus
- south Pacific
- Eschar, headache, rash (trunk→extremities), CNS
- trombiculid mite vector
- significant mortality
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Term
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Definition
- Rickettsial pox
- rash at mite bite, trunk, palm, sole, oropharyngeal mucosa
- can look like chicken pox but lesions get much worse
- house mouse mite vector
- recovery in 10 days without treatment
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Term
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Definition
- Rocky Mountain Spotted Fever
- rash from extremities→trunk
- sever endothelial damage, thrombosis, disseminated intravascular coagulation
- significan mortality
- wood and dog tick vectors - seasonal occurence
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Term
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Definition
- Erlichiosis
- like RMSF w/out rash - fever, chills, headache, myalgia
- organism multiplies in WBCs - large and small forms found (like Chlamydia)
- transmitted by Ixodis ticks
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Term
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Definition
- gram- obligate intracellular pleomorphic parasite
- air stable and highly infective - 1 bacterium can cause symptoms
- transmitted by droplet - does not require vector
- clinical picture of Q fever
- acute disease
- 2-3 wk incubation
- high fever, severe fatigue, myalgia
- pneumonia or hepatitis may develop
- chronic disease
- involves heart, more difficult to treat
- 1-2% mortality due to myocarditis, pericarditis, encephalitis
- Pathogenesis
- associated with contact with infected livestock
- inhalation of dust or droplets containing live organisms, drinking unpasteurized milk
- transmission by arthropod vector b/w animals but rare in humans
- person to person transfer also rare
- Diagnosis
- symptoms + history
- serology
- Treatment
- tetracycline + fluoroquinolone
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