This virus causes, erythema infectiosum, also sometimes called "fifth disease" or "slapped cheek disease" because of the facial rash. Parvovirus B19 replicates in red cell precursors in the bone marrow, and may cause a temporary shut-down in red cell production that will will precipitate an "aplastic crisis" i.e. severe anaemia.
Parvoviruses are the smallest known DNA-containing viruses. The capsids have icosahedral symmetry, and are approximately 25nm in diameter.