Aims:  Quantitative PCR and a culture method were used to investigate Campylobacter occurrence over 3 years in a watershed located in southern Ontario, Canada that is used as a source of drinking water. Methods and Results:  Direct DNA extraction from river water followed by quantitative PCR analysis detected thermophilic campylobacters at low concentrations (<130 cells 100 ml−1) in 57–79% of samples taken from five locations. By comparison, a culture‐based method detected Campylobacter in 0–23% of samples. Water quality parameters such as total Escherichia coli were not highly correlated with Campylobacter levels, although higher pathogen concentrations were observed at colder water temperatures (<10°C). Strains isolated from river water were primarily nalidixic acid‐susceptible Campylobacter lari, and selected isolates were identified as Campylobacter lari ssp. concheus. Campylobacter from wild birds (seagulls, ducks and geese) were detected at a similar rate using PCR (32%) and culture‐based (29%) methods, and although Campylobacter jejuni was isolated most frequently, C. lari ssp. concheus was also detected. Conclusions:  Campylobacter were frequently detected at low concentrations in the watershed. Higher prevalence rates using quantitative PCR was likely because of the formation of viable but nonculturable cells and low recovery of the culture method. In addition to animal and human waste, waterfowl can be an important contributor of Campylobacter in the environment. Significance and Impact of the Study:  Results of this study show that Campylobacter in surface water can be an important vector for human disease transmission and that method selection is important in determining pathogen occurrence in a water environment.

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This study used histo-blood group antigen-conjugated beads to detect norovirus (NoV) in contaminated strawberries, green onions, lettuce, and deli ham. In addition, multiple strains of NoV from genogroups I and II were recovered. This provides an effective protocol for food testing in the investigation of suspected NoV outbreaks.

Frozen raw breaded chicken products (FRBCP) have been identified as a risk factor for Salmonella infection in Canada. In 2017, Canada implemented whole genome sequencing (WGS) for clinical and non-clinical Salmonella isolates, which increased understanding of the relatedness of Salmonella isolates, resulting in an increased number of Salmonella outbreak investigations. A total of 18 outbreaks and 584 laboratory-confirmed cases have been associated with FRBCP or chicken since 2017. The introduction of WGS provided the evidence needed to support a new requirement to control the risk of Salmonella in FRBCP produced for retail sale.

SUMMARYEnteric viruses including norovirus and rotavirus are leading causes of gastroenteritis in Canada. However, only a small number of clinical cases are actually tested for these pathogens leading to systematic underestimation of attributed hospitalizations in administrative databases. The objective of this analysis was to estimate the number of hospitalizations due to norovirus and rotavirus in Canada. Hospitalization records for acute gastroenteritis-associated discharges at all acute-care hospitals in Canada between 2006 and 2011 were analysed. Cause-unspecified gastroenteritis hospitalizations were modelled using age-specific negative binomial models with cause-specified gastroenteritis admissions as predictors. The coefficients from the models were used to estimate the number of norovirus and rotavirus admissions. The total annual hospitalizations for rotavirus were estimated to be between 4500 and 10 000. Total annual hospitalizations for norovirus were estimated to be between 4000 and 11 000. The mean total annual cost associated with these hospitalizations was estimated to be at least $16 million for rotavirus and $21 million for norovirus (all figures in Canadian dollars). This study is the first comprehensive analysis of norovirus and rotavirus hospitalizations in Canada. These estimates provide a more complete assessment of the burden and economic costs of these pathogens to the Canadian healthcare system.

As of May 23, 2017, 29 cases of a new Escherichia coli O121 infection have been identified in six provinces (Alberta, British Columbia, Newfoundland and Labrador, Ontario, Quebec and Saskatchewan) linked with the consumption of uncooked flour. One additional case was identified in a U.S. resident who traveled to Canada during the exposure period. Patients' ages ranged from 2-79 years (median = 23.5 years) and 50% were female.Eight patients were hospitalized, and one developed hemolytic uremic syndrome. Because of the recent emergence of E. coli outbreaks linked to flour, public health professionals should consider flour as a possible source in E. coli outbreaks and communicate the risk associated with flour and raw batter/dough exposure in public health messaging.Affiliations

On December 29, 2016, PulseNet Canada identified a cluster of six Escherichia coli non-O157 isolates with a matching pulsed-field gel electrophoresis (PFGE) pattern combination that was new to the PulseNet Canada database. The patients resided in three geographically distinct provinces. In January 2017, the Public Health Agency of Canada (PHAC) initiated an investigation with local, provincial, and federal partners to investigate the source of the outbreak. A case was defined as isolation of E. coli non-O157 with the outbreak PFGE pattern or closely related by whole genome sequencing (WGS) in a Canadian resident or visitor with onset of symptoms of gastroenteritis on or after November 1, 2016. Patients' illness onset dates ranged from November 2016 to April 2017 (Figure). As of May 23, 2017, a total of 29 cases were identified in six provinces (Alberta,

Background: Cyclospora is an intestinal parasite that is not endemic in Canada. However, national outbreaks of locally acquired cases have been reported since 2013. These outbreaks were suspected to be associated with consumption of produce imported from countries where Cyclospora is endemic. Identification of the source can be challenging because of reporting delays and limited traceability of produce. Objective: To report on a national outbreak of locally acquired cyclosporiasis, highlight the challenges of investigating these outbreaks and document the first time use of a control bank to recruit controls for a national outbreak case-control study in Canada. Methods: Cases of cyclosporiasis were identified through provincial laboratory testing and reported through provinces to the national level. Cases were interviewed about food exposures using a questionnaire and food exposures reported by cases were compared to Foodbook reference values. To narrow down the food items of interest, a matched case-control study was conducted. Controls for the study were recruited primarily from a control bank, that is, a list of individuals who had previously agreed to participate in public health-related surveys. Results: In total, 87 cases of locally acquired cyclosporiasis with onset or report dates between May 19, 2016 and August 10, 2016 were reported by four provinces. Comparing case exposures to Foodbook reference values identified several food items of interest, including blackberries, other berries, herbs and leafy greens. The case-control study identified only blackberries and mesclun greens as significantly more frequently consumed by cases than controls. Due to lack of product details for blackberries and mesclun greens, the source of the outbreak was not conclusively identified. Conclusion: Blackberries were the primary food item of interest, but could not be identified as the conclusive source due to lack of traceability. The control bank was found to be a useful tool for control recruitment.