An outbreak of human parainfluenza virus 3 infection in an outpatient hematopoietic stem cell transplantation clinic

BackgroundParainfluenza viruses cause respiratory tract infections in adults and children, with peak activity during the spring and summer months. Human parainfluenza virus type 3 (hPIV-3) can contribute to significant morbidity and mortality in patients undergoing hematopoietic stem cell transplantation (HSCT).MethodsAutomated surveillance software was used to identify an hPIV-3 outbreak in an HSCT clinic. Active surveillance for respiratory illness and infection control measures were instituted. A retrospective molecular investigation of outbreak viral strains was performed by direct sequencing.ResultsTwelve of 196 HSCT recipients attending the clinic during the outbreak period had hPIV-3; one of these patients died. Sequencing demonstrated highly related strains in 9 of 10 patients studied. Despite the ongoing presence of hPIV-3 outside the inpatient/outpatient care continuum clinic, only 2 cases were observed after institution of respiratory season infection control measures.ConclusionsThis investigation demonstrates the utility of surveillance software in the identification of respiratory virus outbreaks and the importance of rapid implementation of infection control/prevention measures for containment of outbreaks.