Parvovirus

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