Nosocomial outbreak of parvovirus B19 infection in a renal transplant unit

Background. Parovirus B19 (B19) infection is known to cause chronic infecti on leading to anemia in immunocompromised patients, Although nosocomial B19 infections in immunocompetent patients have been documented, no outbreaks in immunocompromised patients have been previously reported. Whether transm ission can occur from a patient with chronic infection is also unknown. Methods. An outbreak of B19 infection in a renal transplant unit was invest igated by molecular analysis of the virus strains and a case-control study. Results. Three patients had genetically identical virus strains suggesting the occurrence of nosocomial transmission. The index case transmitted infec tion many weeks after the onset of her clinical symptoms. Other patients at risk of acquiring infection were those most intensively immunosuppressed, Viral load in the serum correlated with the hematological response. A rebou nd in the viral load was associated with clinical relapse and the failure o f i.v. immunoglobulin therapy. Conclusion. Nosocomial transmission of B19 can occur from immunocompromised patients even when they are in the chronic stage of the infection. The cli nical and virological response to i.v. immunoglobulin therapy is variable a nd depends on the overall level of immunosuppression of the patient.