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23 Cards in this Set
- Front
- Back
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What is the structure of Y. pestis?
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Encapsulated small rods or coccobacillus
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Which animals are reservoirs for Y. pestis?
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Prairie dogs
Rats Squirrels |
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Which is the predominant reservoir in the US for Y. pestis?
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Prairie dogs
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How is Y. pestis transmitted to humans?
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Fleas
Respiratory droplets Ingestion of contaminated human tissue |
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Does Y. pestis replicate in humans?
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NO
humans are dead-end hosts |
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What does it mean that humans are dead-end hosts for Y. pestis?
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Dead-end hosts accidentally become infected and do not participate in the life cycle of the pathogen
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What is the incubation period for Y. pestis?
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2-8 days
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How does the virulene of Y. pestis compare to other organisms?
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It is highly virulent:
1 to 10 organisms are sufficient to elicit disease |
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What are five major virelence factors of Y. pestis?
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1) F-1 envelope antigen confers antiphagocytic properties
2) Endotoxin 3) Exotoxin 4) V antigen 5) W antigen |
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What are three clinical manifestations of Y. pestis?
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Bubonic plague
Pneumonic plague Meningitic plague |
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What are the symptoms of bubonic plague?
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Buboes
Fever chills Headache Myalgias Weakness |
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What are buboes?
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Swollen, painful, sometimes weepy lymph nodes typically found in the groin, axilla, and neck
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What are the clinical manifestations of pneumonic plague?
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Purulent pneumonia
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What are the endotoxin-related symptoms of plague?
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DIC
Septic shock Cutaneous hemorrhages Hypotension |
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What is a complication of disseminated infection?
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Plague meningitis
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How is Y. pestis diagnosed?
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Clinical presentation
Gram stain Culture on MacConkey or blood agar |
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How does Y. pestis appear on Gram stain?
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Rods or coccobacilli with bipolar staining.
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What does bipolar staining mean regarding Y. pestis?
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Staining on either end of the organism with a central clear area.
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What is the treatment for Y. pestis?
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Streptomycin is best, but gentamycin and tetracycline are alternatives.
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What is the treatment for plague meningitis?
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Chloramphenicol, because of good CNS penetration.
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What is the mortality rate of untreated bubonic plague?
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50%
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What is the mortality rate of untreated pneumonic plague?
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Almost always fatal.
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What type of vaccine is available for Y. pestis?
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Killed vaccine for those at high risk
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