NOSOCOMIAL OUTBREAK OF PARVOVIRUS B19 INFECTION IN A RENAL TRANSPLANT UNIT

Abstract

842 Parvovirus B19 (PV B19) infection may cause aplastic anemia in immunocompromised patients. Outbreak of PV B19 infection among renal transplant patients has not been reported. We described an outbreak of PV B19 associated aplastic anemia in a renal transplant unit. Possible nosocomial transmission was investigated. Sera were tested for PV B19 IgG & IgM antibodies by an indirect immunofluorescence assay (Biotrin International, Dublin, Ireland). PV B19 DNA was detected using a nested PCR method. Phylogenetic analysis was performed on a 508bp segment of the NS-1 gene using the clustal method (DNASTAR, London, UK). Sera from 2 patients with active PV B19 infection not related to this outbreak were used as control. From August to September 1997, three renal transplant patients from the same ward developed sudden onset of anemia. There was no evidence of hemolysis or GI bleeding. Bone marrow biopsy performed in 2 of the 3 patients revealed erythroid hypoplasia and the presence of giant pronormoblasts. All 3 patients were seropositive for PV B19 IgM and IgG antibodies. PV B19 DNA was also detected in their sera. Sera from 14 staff and 13 other patients from the same ward were tested for PV B19 IgM antibody and none of them showed positive results. Phylogenetic analysis on the PV B19 isolates from these 3 patients showed that they were genetically identical and different from those isolated from the control cases. Two patients received IVIG therapy. The first patient who had received the most intense immunosuppression failed to respond and died subsequently because of overwhelming sepsis. The other patient recovered. The third patient's anemia resolved spontaneously without treatment. Strict infection control measures were implemented in our unit after the outbreak and no more cases of PV B19 infection were diagnosed afterwards. Our findings documented the nosocomial transmission of PV B19 infection among renal transplant recipients. Early detection and effective isolation measures are essential to prevent spreading of the infection among immunocompromised patients.