Human parvovirus infections.

Discovered by chance in 1974, the human serum parvovirus B19 is at present the only recognized, autonomous, pathogenic human parvovirus. For some years following its discovery, B19 was not associated with any defined clinical syndrome; although a high titre viraemia was often noted in infected individuals they were largely asymptomatic. In 1980 the causal association between B19 infection and aplastic crisis in chronic haemolytic anaemia began to emerge with the discovery of B19 as the agent responsible for aplastic crisis in sickle cell anaemia. This fulfilled the expectation of a disease of tissue comprising a large proportion of dividing cells, namely the erythropoietic elements of the bone marrow, anticipated in autonomous parvovirus infection where viral replication is confined to dividing cells. More recently, erythema infectiosum, an illness sharing many of the clinical features of rubella, has been found to be the common result of B19 infection, although a spectrum of disease is now emerging. Much effort is currently directed toward the elucidation of the effects of maternal B19 infection on the developing fetus.