MOLECULAR EPIDEMIOLOGY OF A PARAINFLUENZA TYPE-3 VIRUS OUTBREAK ON A PEDIATRIC WARD

Parainfluenza type 3 virus (PIV-3), an important cause of acute lower respiratory illness in children, can be transmitted nosocomially. To d ifferentiate between nosocomial transmission and community-acquired in fection, a polymerase chain reaction-based sequencing assay was develo ped for the 5' noncoding region of the PIV-3 fusion protein gene and w as applied to virus specimens from 10 children infected with PIV-3 dur ing a hospital outbreak. Four strains of PIV-3 were identified among t he 10 virus isolates. Six isolates, which appeared to belong to 1 stra in, were obtained from a cluster of nosocomial cases in a pediatric in termediate care unit. In contrast, the remaining 4 isolates, which app eared to belong to 3 different strains, were obtained from children in fected in the community or elsewhere in the hospital. These data indic ate that multiple strains of PIV-3 can be found during a single epidem ic and provide evidence that infections within the intermediate care u nit were probably caused by transmission of 1 strain of virus within t he unit rather than reintroduction of virus by new patients or staff.