Parvovirus infection in children.

Human parvovirus, discovered fortuitously in 1975, is probably most often associated with an asymptomatic or mild nonspecific illness. This small DNA virus, like other members of the Parvoviridae, has a predeliction for rapidly growing cells, especially the erythroid precursor cells of bone marrow. The virus has now clearly been associated with specific clinical syndromes. Epidemiologic and experimental evidence clearly document human parvovirus as the etiologic agent of the acute aplastic crisis associated with various forms of chronic hemolytic anemia. It is also the etiologic agent of erythema infectiosum, the most frequent presentation of acute parvovirus infection in the normal child. The rash of erythema infectiosum is faint and evanescent and may not always be present or recognized, especially in black children. Frequently this infection may occur as a nonspecific viral syndrome in children or adults, accounting for the high incidence of seropositivity among adults despite an infrequent history of erythema infectiosum. The attack rate is highest among 7- to 10-year old contacts. Severe infection in the fetus has been associated with second trimester abortion. Persistent infection in an immunocompromised child has been associated with chronic aplasia of all marrow elements, suggesting the importance of a normal host immune system to contain this infection. The arthritis and arthralgia seen in older patients, especially women, occur after the viremia has ended, suggesting a possible immunologic pathogenesis for this complication. Volunteer studies have delineated the time course of the various manifestations of parvovirus infection. The ability to infect volunteers intranasally and the finding of virus in respiratory secretions suggests that this may be the route of spread to susceptible contacts.