Parvovirus B19 is a nonenveloped, single-stranded DNA virus that targets erythroid progenitor cells, inhibiting erythropoiesis and causing varied clinical manifestations. Parvovirus B19 infection occurs worldwide and is commonly seen during the late winter to early summer. Three genotypes (genotypes 1, 2, and 3) have been identified and vary in geographic distribution. Genotype 1 is the most common and is found worldwide. Genotype 2 is restricted to the United States and Europe. Genotype 3 is found in sub-Saharan Africa and South America. 

Parvovirus B19 is most often transmitted via respiratory droplets; however, vertical transmission and hematogenous transmission may occur. Infection can occur throughout life. Approximately half of individuals are seropositive by 15 years of age, while over 70% of adults have measurable parvovirus B19-specific IgG antibodies.

Clinical manifestations and severity of disease depend on host characteristics, including age, sex, and general health prior to infection. Most individuals are either asymptomatic or experience nonspecific, flu-like symptoms. Approximately 25% will experience clinical conditions associated with parvovirus B19 infection, including erythema infectiosum, arthropathy, transient aplastic crisis, chronic red cell aplasia, and/or fetal death. Individuals most at risk for development of serious complications include patients with underlying hematologic disease, immunosuppressed patients, and pregnant patients (infection during pregnancy may rarely lead to fetal death).