Key Points

• Togaviruses
  • Characteristics
    • RNA viruses
      • replicate in the cytoplasm of cells
      • Single-stranded
    • + sense
    • Linear chromosome
    • Enveloped
    • Icosahedral capsid
  • Viruses of Medical importance
    • Chikungunya virus
      • Transmission
        • Arthropod-borne: Aedes mosquito
          • Co-infection with Dengue virus can occur
      • Presentation: Chikungunya fever
        • Flu-like illness (fever, nausea/vomiting, myalgias, malaise)
        • Polyarthralgias
        • Diffuse macular rash
    • Rubella virus
      • Transmission
        • Respiratory droplets
          • usually affects children
        • Vertical transmission
      • Presentation
        • Rubella
          • Also known as German Measles or 3-day Measles
          • Fever
          • Lymphadenopathy (esp. postauricular)
          • Arthralgias
          • Maculopapular rash
            • Starts on face and spreads downwards to involve trunk and extremities
        • Congenital Rubella
          • Sensorineural deafness
          • Cataracts
          • Cardiac malformations (e.g. PDA)
            • Close with indomethacin
          • Blueberry muffin appearance
            • due to dermal extramedullary hematopoiesis
          • Developmental delay may be seen
      • Treatment
        • Supportive
      • Prophylaxis
        • MMR vaccine (Measles, Mumps, Rubella) - live attenuated
          • Given at 12-15 months of age
          • Has greatly reduced incidence of congenital rubella
    • Eastern and Western Encephalitis