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16 Cards in this Set
- Front
- Back
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name the 5 medically important zoonotic gram neg rods?
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Yersinia
Franciscella Brucella Pasteurella bartonella |
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Which zoonotic organisms are facultative intracellular organisms?
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Franciscella, Brucella and Yersinia
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Describe the morphology of Yersinia pestis?
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Non-motile, bipolar staining pleomorphic Gram neg coccobacillus,.
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What diseases does Y. pestis cause?
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Bubonic plague
septicemic plague pneumonic plague |
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How is Y. pestis typically transmitted?
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Rat flea bite/contact with infected animal or via respiratory aerosols(pneumonic plague).
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What are the important animal reservoirs for Y. pestis?
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rats and prarie dogs(US)
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How virulent is Y. pestis?
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Extremely. 1-10 organisms can cause disease.
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name the important virulence factors for Y. pestis.
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F1 envelope antigen
V antigen W antigen endotoxin |
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What is the purpose of the F1 envelope antigen?
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Inhibits phagocytosis and allows Y. pestis to survive intracellularly in the lymph nodes causing necrosis and bubboes.
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What is the progression of disease in a person infected with Y. pestis?
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Initially lymph nodes will swell and become erythematous, warm and painful(buboes). Then fever and myalgia begin. Next, lung infection(pneumonic form) is virtually fatal and sepsis may occur.
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Why is the black plague referred to as the "Black death".
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Cutaneous hemorrhage and DIC cause a black discoloration.
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How is Y. pestis treated/
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Streptomycin, gentamicin or doxycycline.
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What type of vaccine against Y. pestis is available?
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A killed whole cell vaccine protects against bubonic plague and not pneumonic plague.
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How is Yersinia enterocolitica transmitted to humans and what does it cause?
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Consumption of contaminated meat, animal feces and unpasteurized milk leads to enterocolitis(fever and bloody diarrhea) similar to salmonella and Shigella infections.
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Y. enterocolitica infection is often confused with what condition?
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Appendicitis. Y. enterocolitica causes mesenteric adenitis(focal ulcerations in the ileum with swelling of the mesenteric lymphnodes, presenting with fever, right lower quadrant pain and leukocytosis.
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How is Y. enterocolitica treated?
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Fluoroquinolones or TMP-SMX. It is resistant to cephalosporins.
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