Acute severe hepatitis of unknown origin in children in Canada.

Background: In spring 2022, a series of reports from the United Kingdom and the United States identified an increase in the incidence of acute severe hepatitis in children. The Public Health Agency of Canada (PHAC) collaborated with provincial/territorial health partners to investigate in Canada. Clinical hepatitis, or inflammation of the liver, is not reportable in Canada, so to determine if an increase was occurring above historical levels, the baseline incidence in Canada was estimated. This article estimates the pre-existing baseline incidence of acute severe hepatitis of unknown origin in children in Canada using administrative databases. It further summarizes the outbreak investigation using information from the national case report forms. Methods: A committee with representatives from PHAC and provincial/territorial health partners was established to investigate current cases in Canada. A national probable case definition and case report form were developed, and intentionally created to be highly sensitive to capture all potential cases for etiological investigations. To estimate a nationally representative baseline incidence, hospitalization data were extracted from the Discharge Abstract Database and was combined with data from Québec from the Ministère de la Santé et des Services sociaux. Results: Twenty-eight probable cases of acute severe hepatitis of unknown origin in children were reported between October 1, 2021, to September 23, 2022, by six provinces: British Columbia=1; Alberta=5; Saskatchewan=1; Manitoba=3; Ontario=14; and Québec=4. The estimated national baseline incidence was an average of 70 cases annually, or 5.8 cases per month. Conclusion: There was no apparent increase above the estimated historical baseline levels.

Investigation of acute severe hepatitis in children: A review of liver transplant data, Canada, 2021-2022.

An increase in severe acute hepatitis of unknown etiology was first reported in the United Kingdom in April 2022. Following this report, the Public Health Agency of Canada connected with three paediatric liver transplant centres across Canada to determine if an increase in liver transplants was noted. Data demonstrated no observable increase in the number of transplants conducted in 2022. These data in conjunction with a federal, provincial, territorial investigation provided insight into the situation in Canada.

Outbreak of Escherichia coli O157:H7 Infections Linked to Mechanically Tenderized Beef and the Largest Beef Recall in Canada, 2012.

Contaminated beef is a known vehicle of Escherichia coli O157:H7 infection, although more attention is given to the control of E. coli O157:H7 in ground, rather than whole-cut, beef products. In September 2012, an investigation was initiated at an Alberta, Canada, beef plant after the detection of E. coli O157:H7 in two samples of trim cut from beef originating from this plant. Later in September 2012, Alberta Health Services identified five laboratory-confirmed infections of E. coli O157:H7, and case patients reported eating needle-tenderized beef steaks purchased at a store in Edmonton, Alberta, produced with beef from the Alberta plant. In total, 18 laboratory-confirmed illnesses in Canada in September and October 2012 were linked to beef from the Alberta plant, including the five individuals who ate needle-tenderized steaks purchased at the Edmonton store. A unique strain of E. coli O157:H7, defined by molecular subtyping and whole genome sequencing, was detected in clinical isolates, four samples of leftover beef from case patient homes, and eight samples of Alberta plant beef tested by industry and food safety partners. Investigators identified several deficiencies in the control of E. coli O157:H7 at the plant; in particular, the evaluation of, and response to, the detection of E. coli O157 in beef samples during routine testing were inadequate. To control the outbreak, 4,000 tons of beef products were recalled, making it the largest beef recall in Canadian history. This outbreak, in combination with similar outbreaks in the United States and research demonstrating that mechanical tenderization can transfer foodborne pathogens present on the surface into the interior of beef cuts, prompted amendments to Canada's Food and Drug Regulations requiring mechanically tenderized beef to be labeled as such and to provide safe cooking instructions to consumers. A detailed review of this event also led to recommendations and action to improve the safety of Canada's beef supply.

Multistate Outbreak of Listeriosis Associated with Packaged Leafy Green Salads, United States and Canada, 2015-2016.

We investigated an outbreak of listeriosis detected by whole-genome multilocus sequence typing and associated with packaged leafy green salads. Nineteen cases were identified in the United States during July 5, 2015-January 31, 2016; isolates from case-patients were closely related (median difference 3 alleles, range 0-16 alleles). Of 16 case-patients interviewed, all reported salad consumption. Of 9 case-patients who recalled brand information, all reported brands processed at a common US facility. The Public Health Agency of Canada simultaneously investigated 14 cases of listeriosis associated with this outbreak. Isolates from the processing facility, packaged leafy green salads, and 9 case-patients from Canada were closely related to US clinical isolates (median difference 3 alleles, range 0-16 alleles). This investigation led to a recall of packaged leafy green salads made at the processing facility. Additional research is needed to identify best practices and effective policies to reduce the likelihood of Listeria monocytogenes contamination of fresh produce.

Notes from the Field: Outbreak of Listeriosis Associated with Consumption of Packaged Salad - United States and Canada, 2015-2016.

In September 2015, PulseNet, the national molecular subtyping network for foodborne disease surveillance, identified a cluster of Listeria monocytogenes (Listeria) clinical isolates indistinguishable by two-enzyme pulsed-field gel electrophoresis (PFGE) pattern combination and highly related by whole-genome multilocus sequence typing (wgMLST). A case was defined as isolation of Listeria with the outbreak PFGE pattern and highly related by wgMLST with an isolation date on or after July 5, 2015, the isolate date of the earliest case in this cluster.

Cyclospora infection linked to travel to Mexico, June to September 2015.

Cyclospora cayetanensis was identified in 176 returned travellers from the Riviera Maya region of Mexico between 1 June and 22 September 2015; 79 in the United Kingdom (UK) and 97 in Canada. UK cases completed a food exposure questionnaire. This increase in reported Cyclospora cases highlights risks of gastrointestinal infections through travelling, limitations in Cyclospora surveillance and the need for improved hygiene in the production of food consumed in holiday resorts.

Summary of 11 years of enteric outbreak investigations and criteria to initiate an investigation, Province of Quebec, 2002 through 2012.

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.

Exposure to hospital roommates as a risk factor for health care-associated infection.

BACKGROUND: Numerous patient- and hospital-level characteristics have been established as risk factors for the transmission of health care-associated infections (HAIs). Few studies have quantitatively assessed the impact of exposure to hospital roommates on the acquisition of infections. This study evaluated the association between roommate exposures and the risk of HAIs. METHODS: A retrospective cohort of adult patients admitted to a Canadian teaching hospital between June 30, 2001, and December 31, 2005, was studied. Exposures were characterized as total daily roommate exposures and daily unique roommate exposures. Outcomes examined were methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and Clostridium difficile. RESULTS: The number of roommate exposures per day was significantly associated with MRSA and VRE infection or colonization (MRSA: hazard ratio [HR] = 1.10, 95% confidence interval [CI] = 1.05 to 1.15; VRE: HR = 1.11, 95% CI = 1.02 to 1.21), and with C difficile infection (HR = 1.11, 95% CI = 1.03 to 1.19). A significant association also was found for number of unique roommate exposures per day and VRE (HR = 1.15, 95% CI = 1.02 to 1.28). CONCLUSIONS: The significant associations found between daily roommate exposures and the infection outcomes suggest a possible role for limiting patient-to-patient contact in an infection prevention and control program in this facility. These findings have implications for the deployment and design of acute care hospitals.

Plasma organochlorine levels and prostate cancer risk.

A case-control study was conducted to determine the association between plasma organochlorine levels and prostate cancer risk. Male clinic patients scheduled for prostate core biopsy or seeing their urologist for other conditions from 1997 through 1999 in Kingston, Ontario were eligible, excluding those with an earlier cancer. Age frequency matched controls (n=329) were compared with 79 incident prostate cancer cases. Before knowledge of diagnosis, the patients completed a questionnaire and donated 15 ml of blood for the measurement of 14 PCBs, and 13 organochlorine pesticides by gas chromatography. At least 70% of patients had detectable levels of nine PCB congeners and seven pesticides, and these chemicals were included in the risk analysis adjusted for total lipids. Geometric means for these PCB congeners, total PCBs, and p,p'-DDE are slightly lower for cases than controls, whereas the levels of p,p'-DDT and other pesticides are virtually equal. Adjusting for age and other confounders in multivariable logistic regression, odds ratios (ORs) are consistently below 1.0 for PCB congeners and total PCBs. For pesticides, most ORs are very close to the null. This study suggests that long-term low-level exposure to organochlorine pesticides and PCBs in the general population does not contribute to increased prostate cancer risk.

A comparison of direct versus self-report measures for assessing physical activity in adults: a systematic review.

BACKGROUND: Accurate assessment is required to assess current and changing physical activity levels, and to evaluate the effectiveness of interventions designed to increase activity levels. This study systematically reviewed the literature to determine the extent of agreement between subjectively (self-report e.g. questionnaire, diary) and objectively (directly measured; e.g. accelerometry, doubly labeled water) assessed physical activity in adults. METHODS: Eight electronic databases were searched to identify observational and experimental studies of adult populations. Searching identified 4,463 potential articles. Initial screening found that 293 examined the relationship between self-reported and directly measured physical activity and met the eligibility criteria. Data abstraction was completed for 187 articles, which described comparable data and/or comparisons, while 76 articles lacked comparable data or comparisons, and a further 30 did not meet the review's eligibility requirements. A risk of bias assessment was conducted for all articles from which data was abstracted. RESULTS: Correlations between self-report and direct measures were generally low-to-moderate and ranged from -0.71 to 0.96. No clear pattern emerged for the mean differences between self-report and direct measures of physical activity. Trends differed by measure of physical activity employed, level of physical activity measured, and the gender of participants. Results of the risk of bias assessment indicated that 38% of the studies had lower quality scores. CONCLUSION: The findings suggest that the measurement method may have a significant impact on the observed levels of physical activity. Self-report measures of physical activity were both higher and lower than directly measured levels of physical activity, which poses a problem for both reliance on self-report measures and for attempts to correct for self-report - direct measure differences. This review reveals the need for valid, accurate and reliable measures of physical activity in evaluating current and changing physical activity levels, physical activity interventions, and the relationships between physical activity and health outcomes.