title: Norovirus outbreaks from drinking water.
abstract: As part of an intensified monitoring program for foodborne disease outbreaks in Finland, waterborne outbreaks were investigated for viruses. The diagnostic procedure included analysis of patients' stool samples by electron microscopy and reverse transcription-polymerase chain reaction (RT-PCR) for noroviruses and astroviruses. When these test results were positive for a virus, the water sample was analyzed. Virus concentration was based on positively charged filters from 1-L samples. Of the total 41 waterborne outbreaks reported during the observation period (1998-2003), samples from 28 outbreaks were available for analysis. As judged by RT-PCR results from patient samples, noroviruses caused 18 outbreaks. In 10 outbreaks, the water sample also yielded a norovirus. In all but 1 instance, the amplicon sequence was identical to that recovered from the patients. The ubiquity of waterborne norovirus outbreaks calls for measures to monitor water for viruses.
authors.affiliation: Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, HUCH Laboratory Diagnostics, University of Helsinki, 00014 Helsinki, Finland. Leena.Maunula@Helsinki.Fi
authors.forename: Leena
authors.initials: L
authors.lastname: Maunula
authors.forename: Ilkka T
authors.initials: IT
authors.lastname: Miettinen
authors.forename: Carl-Henrik
authors.initials: CH
authors.lastname: von Bonsdorff
mesh_terms: D017250:Caliciviridae Infections / Q000453:epidemiology* / Q000821:virology; D004196:Disease Outbreaks; D005243:Feces / Q000821:virology; D005387:Finland / Q000453:epidemiology; D005618:Fresh Water / Q000821:virology*; D005759:Gastroenteritis / Q000453:epidemiology* / Q000821:virology; D006801:Humans; D008969:Molecular Sequence Data; D029322:Norovirus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D012367:RNA, Viral / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014881:Water Supply
chemical_list: D012367:RNA, Viral