Cluster of Parvovirus Infection Among Hospital Staff Working in Coronary Care Units

Background: Parvovirus B19 is associated with erythema infectiosum in children or arthralgia and arthritis in adults. The virus is relatively conserved and nucleotide identity is expected in viruses that are epidemiologically related. Here, we describe the first cluster of parvovirus infection among hospital staff documented in Taiwan. Methods: Active surveillance was conducted in coronary care units (CCUs) at a 2200-bed teaching hospital for 1 month in 2007. A case defined clinically as occurring in a patient or staff in CCUs with new onset of fever or rash. Serum was tested for parvovirus B19 IgM and IgG by immunoblotting and DNA by nested polymerase chain reaction. When viremia was detected, nucleotide sequences were analyzed and compared with those of two clinical isolates. The attack rate was defined as the cumulative incidence of acute infection in CCU staff and patients during the study period. Results: Among 57 staff and 15 patients, five nurses met the clinical case definition. Three had acute infection as demonstrated by viral DNA and IgM. The attack rate was 5.3% for the staff and zero for patients. Seroprevalence rate was lower in staff than in patients (26.3% vs. 53.3%). The isolates collected from three cases were highly similar to a community isolate, and they varied with each other by 2-6 nucleotides. The isolate collected from a nurse was identical to that from her friend 3 weeks apart and was concordant with mutual transmission. A sequence with 45 nucleotide variations was identified from a staff member with chronic infection who was negative for IgM and had only weak IgG anti-VP1 reaction with immunoblotting. We did not find any patient as the source of infection. Conclusion: We identified a cluster of parvovirus infection that was caused by three circulating strains which did not support the hypothesis of transmission of a single strain in CCUs.