on 29.1.09 with 0 comments

  • EPIDEMIOLOGY: Insect spread.
    • Mosquito-born viruses: prevalent in summer generally.
    • Tick-born viruses: Prevalent year-around.
  • MANIFESTATIONS: Usually asymptomatic, but may be severe disease. 4-7 incubation period for clinical symptoms.
    • Initial Infection: Viruses will replicate in vascular endothelial cells, in subclinical infection.
    • VIREMIA: Most common mild disease. Fever, arthralgia, rash, nausea, vomiting.
      • Dengue Fever: Most common cause
      • Sindbis virus
      • Colorado Tick Fever
    • HEMORRHAGIC FEVER: Extensive hemorrhages from almost any epithelial surface. Can lead to CV collapse and death. Fatality rate ranges from 2% - 50%.
      • Dengue Virus: Dengue Shock Syndrome
      • Yellow Fever: Hemorrhagic fever with hepatitis.
      • From highest to lowest lethality:
        • Eastern Equine Encephalitis
        • St. Louis Encephalitis
        • Western Equine Encephalitis
        • California
      • Symptoms:
        • Starts with Meningitis -- fever, headache, vomiting, stiff neck.
        • Followed by lethargy, confusion, paralysis, and coma and death in most serious cases.
        • May see neuropsychiatric sequelae in non-fatal cases, such as mental retardation, paralysis.
  • IMMUNITY: Acquired and lifelong.
  • DIAGNOSIS: Must use serology. Acute:convalescent titers, or IgM.

Category: Microbiology Notes



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