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Parvovirus

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Key Points

  • Parvovirus B19 virus
    • Characteristics
      • DNA virus
        • Replicates in nucleus
        • Single-stranded
      • No envelope
      • Linear chromosome
      • Smallest DNA virus
    • Transmission
      • Several routes of transmission
        • Respiratory droplets
        • Vertical transmission from mother to fetus
        • Blood/hematogenous
    • Pathogenesis
      • Infects RBC precursors in bone marrow and blood
        • P antigen (bound by parvovirus B19 receptors) expressed mainly on RBCs and precursors
          • May also be found on endothelial cells and other blood components
        • Parvovirus B19 replicates in bone marrow, killing RBC precursors
    • Presentation
      • Erythema infectiosum (Fifth Disease)
        • Note: Fifth disease is historical; one of 6 childhood rashes, named for order they were discovered 
        • Begins with non-specific flu-like prodrome
          • Manifested symptoms of brief viremia
        • “Slapped cheek” rash (malar rash) in children
          • Thought to be mediated by antibody-induced inflammation from immune response to virus
        • Generalized reticular (lace-like) rash on arms, legs, trunk
      • Aplastic anemia
        • Common in sickle cell disease
          • Usually manifests as a pure-red blood cell aplasia, but other blood cell lines may be affected
        • Pure RBC aplasia also seen in adults
          • Rare form of marrow failure
      • Hydrops fetalis
        • Can cause death in fetus if pregnant woman is infected
      • Arthralgia/arthritis
        • Knees, ankles, wrists, and hands involved, with stiffness and pain
      • May cause myocarditis
        • Causal link has not yet been established
    • Diagnosis
      • Anti-parvovirus IgM or IgG on serologies
      • PCR detection
    • Treatment
      • Self-limiting; supportive
        • NSAIDs may be used for arthritic symptoms