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10 Cards in this Set
- Front
- Back
Blood and Lymph- Viral Hemorrhagic Fevers by Blue
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Blood and Lymph- Viral Hemorrhagic Fevers by Blue
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What is the biggest factor in the spread of dengue fever?
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limited mosquito control in most dengue-endemic countries.
vector control is the best way to control these diseases |
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Where is yellow fever? what is the host/vector? how about dengue hf?
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yellow fever- africa/south america; monkeys/mosquitos
dengue hf- global/tropical; monkeys mosquitos *both are flavivirus |
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Pathogenesis, clinical overall summary
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Virus-specific; May involve endothelial cell infection of blood vessels during initial viremia. Mesothelial, reticuloendothelial. Increased vascular permeability (cytokine-induced; e.g., Dengue...macrophage, t cell and b cell... huge cytokine response).
Fever, rash, malaise, myalgia, hemorrhage (petechial, most organs; GI, hepatic most prominent), edema; jaundice. History of recent travel to endemic area. |
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Treatment, prevention overall summary
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Treatment: Fluid and electrolyte balance, transfusion (or plasma,platelets, clotting factor). Isolation, infection control precautions (all body fluids). Ribavirin (Arenavirus and Bunyavirus). *anything to prevent more fluid loss.
Prevention: Vaccine for yellow fever. Under development for dengue, Ebola, Argentinian, Rift Valley. Vector control/eradication, insect repellents; rodent control. *category A biological warfare agents |
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Arbovirus (which includes flavivirus) has something unique and not seen anywhere else in nature. what is that?
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Unique ambisense [mixed (+) and (–) sense] single-stranded RNA genomes.
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clinical presentations of Yellow Fever
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YF mild fever/headache to liver infection (hepatitis & jaundice), nephritis, encephalitis.
Hemorrhage in YF a direct action of the virus (gastric mucosa, *“black vomit”). Liver damage may also induce coagulation defects. *Councilman bodies – intracellular inclusions of viral antigens in hepatocytes. |
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What are the characteristics of the intial infection of Dengue fever (3)?
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fever,
rash muscle and joint pain |
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What is the principle site of replication?
where is the characteristic pain located? |
Entry via mosquito bite.
Dendritic cell is principle site of replication, then through-out reticulo-endothelial system. Mild hepatitis (compared to YF) Fever, headache, anorexia, nausea/vomiting, retro-orbital pain, back pain, skin rash. Deep “bone” pain = “breakbone fever”. Immune complex deposition. Incubation period 3-7 days, disease course 3-9 days. Uncomplicated recovery.Severity directly related to blood virus titer. 4 strains of DF, and protection against one is not protection against other 3. |
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ok, so that was the first exposure to dengue. what happens during second exposure (from a different strain)?
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first exposure: breakbone fever.
second exposure: Dengue Hemorrhagic Fever Antibody-dependent enhancement (ADE) enhanced virus growth cytokine storm, increased vascular permeability (plasma loss) spontaneous hemorrhage, dengue shock syndrome (DSS). |