Prolonged anemia by superinfection of parvovirus B19 in a boy with enterohemorrhagic Escherichia coli O157-associated hemolytic uremic syndrome.

We report a 3-year-old boy with enterohemorrhagic Escherichia coli (EHEC) O157-associated hemolytic uremic syndrome (HUS). His anemia was associated with decreased reticulocyte count and persisted after the recovery from HUS. Superinfection of parvovirus B19 (PVB19) was proven by a transient febrile episode associated with IgM antibodies to the virus and the delayed appearance of IgG antibodies and typical rashes. We conclude that PVB19 infection could induce severe persistent anemia in EHEC-associated HUS. Reticulocytopenia is a clue to the diagnosis in such cases.