title: Summary of 11 years of enteric outbreak investigations and criteria to initiate an investigation, Province of Quebec, 2002 through 2012.
abstract: This article presents a retrospective analysis of enteric disease outbreak investigations led by or conducted in collaboration with provincial health authorities in the Province of Quebec from 2002 through 2012. Objectives were to characterize enteric disease outbreaks, quantify and describe those for which a source was identified (including the control measures implemented), identify factors that contributed to or impeded identification of the source, and recommend areas for improvement in outbreak investigations (including establishment of criteria to initiate investigations). A descriptive analysis of enteric disease outbreak summaries recorded in a provincial database since 2002 was conducted, and corresponding outbreak reports were reviewed. Among 61 enteric disease outbreaks investigated, primary pathogens involved were Salmonella (46%), Escherichia coli O157:H7 (25%), and Listeria monocytogenes (13%). Sources were identified for 37 (61%) of 61 of the outbreaks, and descriptive studies were sufficient to identify the source for 26 (70%) of these. During the descriptive phase of the investigation, the causes of 21 (81%) of 26 outbreaks were identified by promptly collecting samples of suspected foods based on case interviews. Causes of outbreaks were more likely to be detected by weekly surveillance or alert systems (odds ratio = 6.0, P = 0.04) than by serotyping or molecular typing surveillance and were more likely to be associated with a common event or location (odds ratio = 11.0, P = 0.023). Among the 37 outbreaks for which causes were identified, 24 (65%) were associated with contaminated food, and recalls were the primary control measure implemented (54%). Review of enteric outbreaks investigated at the provincial level in Québec has increased the province's ability to quantify success and identify factors that can promote success. Multiple criteria should be taken into account to identify case clusters that are more likely to be resolved.
authors.affiliation: Ministère de la Santé et des Services sociaux du Québec, 1075 chemin Ste-Foy, Québec, Province de Québec, Canada G1S 2M1. colette.gaulin@msss.gouv.qc.ca.
authors.forename: Colette
authors.initials: C
authors.lastname: Gaulin
authors.affiliation: Outbreak Management Division, Centre for Foodborne, Environmental and Zoonotic Infectious Diseases, Public Health Agency of Canada, Unit 120, 255 Woodlawn Road West, Guelph, Ontario, Canada N1H 8J1.
authors.forename: Andrea
authors.initials: A
authors.lastname: Currie
authors.affiliation: Ministère de la Santé et des Services sociaux, 201 rue Crémazie Est, Montréal, Province de Québec, Canada H2M 1L2.
authors.forename: Geneviève
authors.initials: G
authors.lastname: Gravel
authors.affiliation: Outbreak Management Division, Centre for Foodborne, Environmental and Zoonotic Infectious Diseases, Public Health Agency of Canada, 2932 Baseline Road, Tower A, Room 327B, AL 3303B, Ottawa, Ontario, Canada K1A 0K9.
authors.forename: Meghan
authors.initials: M
authors.lastname: Hamel
authors.affiliation: Ministère de la Santé et des Services sociaux du Québec, 1075 chemin Ste-Foy, Québec, Province de Québec, Canada G1S 2M1.
authors.forename: Marie-Andree
authors.initials: MA
authors.lastname: Leblanc
authors.affiliation: Ministère de l'Agriculture, des Pêcheries et de l'Alimentation du Québec, 200 chemin Ste-Foy, 11ème étage, Québec, Province de Québec, Canada G1R 4X6.
authors.forename: Danielle
authors.initials: D
authors.lastname: Ramsay
authors.affiliation: Laboratoire de santé publique du Québec, 20045 chemin Ste-Marie, Sainte-Anne de Bellevue, Québec, Province de Québec, Canada H9X 3R5.
authors.forename: Sadjia
authors.initials: S
authors.lastname: Bekal
mesh_terms: D004196:Disease Outbreaks / Q000266:history; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000266:history / Q000382:microbiology; D019453:Escherichia coli O157 / Q000302:isolation & purification / Q000502:physiology*; D049674:History, 21st Century; D006801:Humans; D008089:Listeria monocytogenes / Q000302:isolation & purification / Q000502:physiology*; D008088:Listeriosis / Q000453:epidemiology* / Q000266:history / Q000382:microbiology; D016017:Odds Ratio; D011792:Quebec / Q000453:epidemiology; D012189:Retrospective Studies; D012475:Salmonella / Q000302:isolation & purification / Q000502:physiology*; D012480:Salmonella Infections / Q000453:epidemiology* / Q000266:history / Q000382:microbiology