title: Increase in outbreaks of gastroenteritis linked to bathing water in Finland in summer 2014.
abstract: An increased number of suspected outbreaks of gastroenteritis linked to bathing water were reported to the Finnish food- and waterborne outbreak (FWO) registry in July and August 2014. The investigation reports were assessed by a national outbreak investigation panel. Eight confirmed outbreaks were identified among the 15 suspected outbreaks linked to bathing water that had been reported to the FWO registry. According to the outbreak investigation reports, 1,453 persons fell ill during these outbreaks. Epidemiological and microbiological data revealed noroviruses as the main causative agents. During the outbreaks, exceptionally warm weather had boosted the use of beaches. Six of eight outbreaks occurred at small lakes; for those, the investigation strongly suggested that the beach users were the source of contamination. In one of those eight outbreaks, an external source of contamination was identified and elevated levels of faecal indicator bacteria (FIB) were noted in water. In the remaining outbreaks, FIB analyses were insufficient to describe the hygienic quality of the water. Restrictions against bathing proved effective in controlling the outbreaks. In spring 2015, the National Institute for Health and Welfare (THL) and the National Supervisory Authority for Welfare and Health (Valvira) published guidelines for outbreak control to prevent bathing water outbreaks.
authors.affiliation: National Institute for Health and Welfare, Department of Health Security, Water and Health Unit, Kuopio, Finland.
authors.forename: Ari
authors.initials: A
authors.lastname: Kauppinen
authors.affiliation: National Institute for Health and Welfare, Department of Health Security, Viral Infections Unit, Helsinki, Finland.
authors.forename: Haider
authors.initials: H
authors.lastname: Al-Hello
authors.affiliation: National Institute for Health and Welfare, Department of Health Security, Water and Health Unit, Kuopio, Finland.
authors.forename: Outi
authors.initials: O
authors.lastname: Zacheus
authors.affiliation: National Supervisory Authority for Welfare and Health, Helsinki, Finland.
authors.forename: Jaana
authors.initials: J
authors.lastname: Kilponen
authors.affiliation: University of Helsinki, Faculty of Veterinary Medicine, Department of Food Hygiene and Environmental Health, Helsinki, Finland.
authors.forename: Leena
authors.initials: L
authors.lastname: Maunula
authors.affiliation: National Institute for Health and Welfare, Department of Health Security, Infectious Disease Control Unit, Helsinki, Finland.
authors.forename: Sari
authors.initials: S
authors.lastname: Huusko
authors.affiliation: Helsinki University Hospital, Laboratory Services (HUSLAB), Department of Clinical Microbiology, Helsinki, Finland.
authors.forename: Maija
authors.initials: M
authors.lastname: Lappalainen
authors.affiliation: National Institute for Health and Welfare, Department of Health Security, Water and Health Unit, Kuopio, Finland.
authors.forename: Ilkka
authors.initials: I
authors.lastname: Miettinen
authors.affiliation: National Institute for Health and Welfare, Department of Health Security, Viral Infections Unit, Helsinki, Finland.
authors.forename: Soile
authors.initials: S
authors.lastname: Blomqvist
authors.affiliation: National Institute for Health and Welfare, Department of Health Security, Infectious Disease Control Unit, Helsinki, Finland.
authors.forename: Ruska
authors.initials: R
authors.lastname: Rimhanen-Finne
mesh_terms: D001493:Bathing Beaches; D017250:Caliciviridae Infections / Q000175:diagnosis / Q000453:epidemiology / Q000821:virology; D003141:Communicable Diseases / Q000453:epidemiology* / Q000209:etiology; D018563:Disease Notification / Q000706:statistics & numerical data; D004196:Disease Outbreaks; D005759:Gastroenteritis / Q000453:epidemiology* / Q000821:virology; D006801:Humans; D029322:Norovirus / Q000302:isolation & purification*; D015995:Prevalence; D011998:Recreation; D012621:Seasons; D014871:Water Microbiology; D014876:Water Pollution
keywords: bathing water; faecal indicator bacteria; gastrointestinal disease; norovirus; surveillance; waterborne outbreaks