THE INCIDENCE AND GENETIC-VARIABILITY OF SMALL ROUND-STRUCTURED VIRUSES IN OUTBREAKS OF GASTROENTERITIS IN THE NETHERLANDS

Small round-structured viruses (SRSV) are a group of RNA viruses that can cause gastroenteritis in persons of all ages. To determine the inc idence of SRSV-associated gastroenteritis in The Netherlands and to st udy the genetic variability of outbreak strains, all outbreaks that we re reported to the epidemiologists of the regional health services in 1996 were investigated using a standardized protocol. In 60 (87%) of t he 69 reported outbreaks, SRSV could be detected, showing the etiologi c significance of SRSV in outbreaks of gastroenteritis in The Netherla nds. Of these outbreaks, 84% occurred in semiclosed communities, such as nursing homes (59%) and hospital wards (25%). Sequence analysis of the outbreak strains revealed that the majority of the strains from Ja nuary to November 1996 formed a tight cluster within genogroup II SRSV , In November 1996, a shift toward genogroup I SRSV occurred, suggesti ng a change to a new predominant strain.