title: A Systematic Review of Waterborne Disease Outbreaks Associated with Small Non-Community Drinking Water Systems in Canada and the United States.
abstract: BACKGROUND
  Reports of outbreaks in Canada and the United States (U.S.) indicate that approximately 50% of all waterborne diseases occur in small non-community drinking water systems (SDWSs). Summarizing these investigations to identify the factors and conditions contributing to outbreaks is needed in order to help prevent future outbreaks.
  
  
  OBJECTIVE
  The objectives of this study were to: 1) identify published reports of waterborne disease outbreaks involving SDWSs in Canada and the U.S. since 1970; 2) summarize reported factors contributing to outbreaks, including water system characteristics and events surrounding the outbreaks; and 3) identify terminology used to describe SDWSs in outbreak reports.
  
  
  METHODS
  Three electronic databases and grey literature sources were searched for outbreak reports involving SDWSs throughout Canada and the U.S. from 1970 to 2014. Two reviewers independently screened and extracted data related to water system characteristics and outbreak events. The data were analyzed descriptively with 'outbreak' as the unit of analysis.
  
  
  RESULTS
  From a total of 1,995 citations, we identified 50 relevant articles reporting 293 unique outbreaks. Failure of an existing water treatment system (22.7%) and lack of water treatment (20.2%) were the leading causes of waterborne outbreaks in SDWSs. A seasonal trend was observed with 51% of outbreaks occurring in summer months (p<0.001). There was large variation in terminology used to describe SDWSs, and a large number of variables were not reported, including water source and whether water treatment was used (missing in 31% and 66% of reports, respectively).
  
  
  CONCLUSIONS
  More consistent reporting and descriptions of SDWSs in future outbreak reports are needed to understand the epidemiology of these outbreaks and to inform the development of targeted interventions for SDWSs. Additional monitoring of water systems that are used on a seasonal or infrequent basis would be worthwhile to inform future protection efforts.
authors.affiliation: Department of Population Medicine, University of Guelph, Guelph, Ontario, Canada.
authors.forename: Wendy
authors.initials: W
authors.lastname: Pons
authors.affiliation: Department of Population Medicine, University of Guelph, Guelph, Ontario, Canada; Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, Guelph, Ontario, Canada.
authors.forename: Ian
authors.initials: I
authors.lastname: Young
authors.affiliation: Department of Population Medicine, University of Guelph, Guelph, Ontario, Canada.
authors.forename: Jenifer
authors.initials: J
authors.lastname: Truong
authors.affiliation: Department of Population Medicine, University of Guelph, Guelph, Ontario, Canada.
authors.forename: Andria
authors.initials: A
authors.lastname: Jones-Bitton
authors.affiliation: Department of Population Medicine, University of Guelph, Guelph, Ontario, Canada.
authors.forename: Scott
authors.initials: S
authors.lastname: McEwen
authors.affiliation: Department of Population Medicine, University of Guelph, Guelph, Ontario, Canada; FoodNet Canada, Centre for Food-borne, Environmental and Zoonotic Infectious Diseases, Public Health Agency of Canada, Ottawa, Ontario, Canada.
authors.forename: Katarina
authors.initials: K
authors.lastname: Pintar
authors.affiliation: Department of Population Medicine, University of Guelph, Guelph, Ontario, Canada.
authors.forename: Andrew
authors.initials: A
authors.lastname: Papadopoulos
mesh_terms: D002170:Canada / Q000453:epidemiology; D004196:Disease Outbreaks; D060766:Drinking Water; D006801:Humans; D014481:United States / Q000453:epidemiology; D014871:Water Microbiology; D014881:Water Supply; D000069578:Waterborne Diseases / Q000453:epidemiology* / Q000209:etiology*
chemical_list: D060766:Drinking Water