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34 Cards in this Set
- Front
- Back
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Disease, Vector Reservoir and Target Tissue for Rickettsia rickettsii
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Disease: Rocky Mt. Spotted Fever
Vector: Tick Reservoir: Dogs, Ticks Target Tissue: Vascular Endothelium |
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Disease, Vector, Reservoir and Target tissue for Rickettsia typhi
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Disease: Endemic Typhus
Vector: Flea Reservoir: Rodents Target Tissue: Vascular Endothelium |
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Disease, Vector, Reservoir and Target Tissue for Rickettsia prowazeki
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Disease:Epidemic Typhus
Vector: Louse Reservoir: Humans, Flying Squirrels Target Tissue: Vascular Endothelium, Macrophages |
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Disease, Vector, Reservoir and Target Tissue for Orientia tsutsugamushi
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Disease: Scrub Typhus
Vector: Chigger Mite Reservoir: Humans Target Tissue: Vascular Endothelium |
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Disease, Vector, Reservoir and Target Tissue for Ehrlichia chaffeensis
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Disease: Ehrlichiosis
Vector:Tick Reservoir: Deer, Rodents Target Tissue: Monocytic Leukocytes |
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Disease, Vector, Reservoir and Target Tissue for Anaplasma phagocytophilum
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Disease: Anaplasmosis
Vector:Tick Reservoir: Rodents, Deer Target Tissue: Polymorphonuclear Leukocytes |
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What are the properties of the bacteria responsible for Rickettsia and Orientia?
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Obligate intracellular
Gram negative LPS and Peptidoglycan present |
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What surface proteins do you serotype for Rickettsia and Orientia?
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OmpA &OmpB
(antibodies develop against these proteins) |
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Where do Rickettsia and Orientia bacteria invade?
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Vascular Endothelial cells via phagocytosis (escape from phagososme to cytoplasm where they obtain ATP, amino acids and phosphorylated sugars)
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How are the Ehrlichia and Anaplasma bacteria different from Rickettsia and Orientia bacteria?
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The cell walls are thinner and they DO NOT contain peptidoglycan or LPS. They also remain in membrane bound vacuoles rather than being free in the cytoplasm.
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What surface proteins do you serotype for Rickettsia and Orientia?
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OmpA &OmpB
(antibodies develop against these proteins) |
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What cells does Ehrlichia invade?
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Monocytic leukocytes
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What cells does Anaplasma invade?
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Polymorphonuclear phagocytes
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Dermacentor Tick
Name the Reservoir, Disease and most common location in the US |
Dog tick
Rocky Mt. Spotted Fever Southeastern and Southcentral US |
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Amblyomma (lone star tick)
Name the Reservoir, Disease and most common location in the US. |
Deer and mice
Ehrlichia Southeastern and Southcentral US |
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Ixodes Tick
Name the Reservoir, Disease and most common location in the US. |
Deer and mice
Anaplasma (also Borrelia and Babesia) Northeastern and Northcentral US |
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Pediculus (human body louse) What does this cause?
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Epidemic Typhus
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Xenopsylla (rodent flea)
What does this cause? |
Endemic Typhus
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Chigger Mite
What does this cause? |
Scrub Typhus
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What cells and cytokines are important in the immune response against these organisms?
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CD8+ T cells for clearance
IFN-gamma and TNF-alpha activate infected endothelial cells to kill organisms |
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Who are at high risk for Rocky Mt Spotted Fever tick exposure and at what time of the year?
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Children during the summer due to outdoor activities
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Who can develop severe / fatal cases of Rocky Mt Spotted Fever?
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Elderly and blacks with G6PD deficiency
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How long does a tick need to feed for Rickettsia to be activated and injected?
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6-10hrs
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What is the incubation time (bite to symptoms) for Rocky Mt Spotted Fever?
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7days (2-14 day range)
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What are the initial symptoms of Rocky Mt Spotted Fever?
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Fever, myalgia, headache
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When does a rash appear in Rocky Mt Spotted fever?
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3-5days after initial symptoms in 90% of patients. Starts on hands, feet or trunk as maculopapular erythema and progresses to petichiae which can progress to necrosis and gangrene.
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What is the treatement for Rocky Mt Spotted Fever?
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Doxycycline
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Where is epidemic typhus common?
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Wars and developing countries. Rare in US because of good hygiene and lack of louse infections.
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What is Brill-Zinsser Disease?
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Persons from a country with epidemic thyphus recover but harbor latent infection that can recrudesce years or decades later after they have emigrated to a country that doesnt have epidemic typhus.
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Where is Scrub Thyphus endemic to?
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Asia: common cause of fever duing Vietnam war.
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What is the classic sign for Scrub Thyphus?
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Eschar: Black Scab at the site of the mite bite. (hard to diagnose because most cases dont show eschar or have rash like Rocky Mt Spotted Fever)
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What are the clinical features of Ehrlichiosis and Anaplasmosis?
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Similar to RMSF: tick-borne, 7-day average incubation period, mostly in summer, doxycycline treatment effective.
Fever, Myalgia and headache but rash less common than RMSF. Leukopenia and thrombocytopenia more common than in RMSF. |
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How is Anaplasmosis Diagnosed?
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Blood smear with round inclusions in neutrophils.
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How is Ehrlichiosis Diagnosed?
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Blood smear with round inclusions in monocytes
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