fifth (5th) disease

Last reviewed 03/2022

Parvovirus B19 virus, discovered accidentally in 1975, is a single-stranded DNA virus belonging to the Parvoviridae family of viruses (1) and it is identified as one of the smallest viruses to infect the mammalian cell (2).

Parvoviruses are species specific and humans are exclusively affected by the type B19 (1).

Transmission of the disease can occur via:

  • respiratory route
  • hand-to-mouth contact
  • blood products
  • vertically from the mother to the fetus (3)

Replication of the virus occurs in rapidly dividing erythroid progenitor cells although other target cells have also been identified e.g – myocardial tissue (1).

The most typical manifestations of parvovirus B19 infection are

  • erythema infectiosum (ie, fifth disease)
  • transient aplastic crisis
  • chronic red cell aplasia
  • arthropathy
  • nonimmune hydrops fetalis (3)

Fifth disease is due to infection with human erythrovirus (formerly parvovirus) type B19, and tends to occur in school-aged children, sometimes occurring in epidemics. As the alternative name indicates, the maculopapular rash associated with this disease often resembles slap marks on the cheeks.

One episode of infection will provide life long immunity in individuals (1).

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