The pink intranuclear inclusions in the erythroid precursors seen here are characteristic for parvovirus infection. Parvovirus, or "fifth disease" is a self-limited infection that can produce a "slapped cheek" appearance of a rash in children, and often goes unnoticed in adults. However, pregnant mothers can pass the virus to the fetus, and a severe anemia with fetal hydrops and intrauterine demise can result.