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20 Cards in this Set
- Front
- Back
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what does typhus mean?
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confusion or delirium
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what is the morphology of the rickettsia?
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small rods or coccoid, gram neg, cytoplasmic membrane-peptidoglycan-outer mebrane - LPS.
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what is the general cycle of rickettsia?
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animal to arthropod (flea or tick). lives in intestine of arthropod and infects humans when it bites them, accidental host, also have transovarian infection with the arthropod.
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describe the pathogenesis of rickettsias.
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insect bite or scratching insect feces into skin leads to local necrotic lesion. Rickettsias are obligate intracellular pathogens that want to get to vascular endothelial cells. Bacteremia ensues and the BV's especially caps are damaged leading to edema, rash from the RBC's, hypotension, etc. Fever and rash from vasculitis and then see petechial rash. eventually hypovolemia, hypoproteinemia and shock (stupor). Can lead to organ failure
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what aids in making clinical diagnosis?
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time of year and where have they been, hiking?? know your endemic areas.
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what labs can be done?
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get a tissue or blood specimen, needs to be grown on live tissue, can do giemsa stain or FLUORESCENT Ab's, PCR in some places, Weil Felix agglutination is no longer performed
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what are the treatments and preventions?
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Tx is tetracycline. Prevent via protective clothing, insect repellents, rodent control... no vaccines
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which bug cause rocky mtn spotted fever?
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R. rickettsii
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what is the epidemiology of rocky mtn?
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tick bite that must last 24 + hrs for saliva to activate the bacs. wood tick is the tick in rocky mtns (rodent tick) and the dog tick is the tick in the east and west. usually in the summer mo's and most common in OK and NC
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what are the symptoms of rocky mtn?
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fever, chills, headache, myalgia, rash that starts at extremities and goes to trunk, hypovolemia, and hypoproteinemia
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what is the pathonumonic symptom of spotted fever?
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rash on hands
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what is the 20% mortality rate of spotted fever due to?
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delayed diagnosis
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what bac causes epidemic AKA louse born typhus?
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R. prowazekii
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what is the epidemiology of louse born typhus?>
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usually human to human via the body louse, usually in crowded conditions, later recrudescence (Brill Zinsser disease). Sporadic in US
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what are the symptoms of louse born typhus?
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normal systemic stuff with fever, rash on trunk of body, stupor... note the recrudescent disease (Brill Zinsser) is usually shorter live bc of our antibodies against it when it goes active again
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what are the lab protocols, treatments and preventions for louse typhus?
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serology, tetracycline, chloramphenicol, louse control and a vaccine that is not given anymore
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what bac causes endemic (murine) typhus?
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R. typhi
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what is the arthropod vector of murine typhus? epidemiology?
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rat flea. rare in US but mainly in gulf states, travelers from tropic or subtropical climate
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what are the symptoms of endemic typhus?
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normal systemic symptoms with a cough, spread of rash from trunk to extremities
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how do you diagnose endemic typhus? how do you treat it?
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serology. tetracycline, chloramphenicol, doxycycline
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