A multi-provincial Salmonella Typhimurium outbreak in Canada associated with exposure to pet hedgehogs, 2017-2020.

Background: In October 2020, an investigation began in Canada on an outbreak of Salmonella Typhimurium infections of the same strain as a concomitant outbreak in the United States (US) that was linked to pet hedgehogs. The objective of this article is to identify the source of the outbreak, determine if there was a link between the Canadian and US outbreaks and identify risk factors for infection to inform public health interventions. Methods: Cases were identified through whole genome sequencing of S. Typhimurium isolates. Information was collected on case exposures, including animal contact. Hedgehog and environmental specimens were tested for S. Typhimurium and a trace back investigation was conducted. Results: There were 31 cases in six provinces, with illness onset dates from June 1, 2017, to October 15, 2020. Median case age was 20 years and 52% were female. Isolates grouped together between 0-46 whole genome multi locus sequence typing allele differences. Of 23 cases with available exposure information, 19 (83%) reported contact with hedgehogs in the seven days prior to symptoms; 15/18 (83%) reported direct contact and 3/18 (17%) reported indirect contact. Trace back investigation did not identify a common source of hedgehogs but uncovered an industry with a complex distribution network. The outbreak strain was detected in samples collected from a hedgehog in one case's home and from a hedgehog in a Québec zoo. Conclusion: Direct and indirect contact with hedgehogs was identified as the source of this S. Typhimurium outbreak. Public health communications aimed to increase awareness about the risks of zoonoses from hedgehogs and shared key hygienic practices to reduce disease transmission.

Acute Toxoplasmosis among Canadian Deer Hunters Associated with Consumption of Undercooked Deer Meat Hunted in the United States.

We conducted a recent investigation in Quebec, Canada, concerning Canadian deer hunters who went to the United States to hunt deer and returned with symptoms of fever, severe headache, myalgia, and articular pain of undetermined etiology. Further investigation identified that a group of 10 hunters from Quebec attended a hunting retreat in Illinois (USA) during November 22-December 4, 2018. Six of the 10 hunters had similar symptoms and illness onset dates. Serologic tests indicated a recent toxoplasmosis infection for all symptomatic hunters, and the risk factor identified was consumption of undercooked deer meat. Among asymptomatic hunters, 2 were already immune to toxoplasmosis, 1 was not immune, and the immune status of 1 remains unknown. Outbreaks of acute toxoplasmosis infection are rare in North America, but physicians should be aware that such outbreaks could become more common.

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.

Veal Liver as Food Vehicle for Human Campylobacter Infections.

A matched case-control study in Quebec, Canada, evaluated consumption of veal liver as a risk factor for campylobacteriosis. Campylobacter was identified in 28 of 97 veal livers collected concurrently from slaughterhouses and retailers. Veal liver was associated with human Campylobacter infection, particularly when consumed undercooked.

Multi-Province Listeriosis Outbreak Linked to Contaminated Deli Meat Consumed Primarily in Institutional Settings, Canada, 2008.

A multi-province outbreak of listeriosis occurred in Canada from June to November 2008. Fifty-seven persons were infected with 1 of 3 similar outbreak strains defined by pulsed-field gel electrophoresis, and 24 (42%) individuals died. Forty-one (72%) of 57 individuals were residents of long-term care facilities or hospital inpatients during their exposure period. Descriptive epidemiology, product traceback, and detection of the outbreak strains of Listeria monocytogenes in food samples and the plant environment confirmed delicatessen meat manufactured by one establishment and purchased primarily by institutions was the source of the outbreak. The food safety investigation identified a plant environment conducive to the introduction and proliferation of L. monocytogenes and persistently contaminated with Listeria spp. This outbreak demonstrated the need for improved listeriosis surveillance, strict control of L. monocytogenes in establishments producing ready-to-eat foods, and advice to vulnerable populations and institutions serving these populations regarding which high-risk foods to avoid.

Escherichia coli O157:H7 Outbreak Associated with the Consumption of Beef and Veal Tartares in the Province of Quebec, Canada, in 2013.

OBJECTIVES: An Escherichia coli O157:H7 outbreak occurred in 2013 that was associated with the consumption of beef and veal tartares in the province of Quebec. This report describes the results of the ensuing investigation. MATERIALS AND METHODS: As the outbreak was identified, all individuals in the province of Quebec affected with the same strain of E. coli O157:H7 as defined by pulsed-field gel electrophoresis were interviewed using a standardized questionnaire. Cases reported from other provinces in Canada were interviewed by their public health authorities and the results were reported to the Quebec public health authorities. Microbiological and environmental investigations were conducted by the Sous-ministériat à la santé animale et à l'inspection des aliments du Ministère de l'Agriculture, des Pêcheries et de l'Alimentation du Québec, by the Ville de Montréal's Food Inspection Branch, and by the Canadian Food Inspection Agency at the restaurants, suppliers, and slaughterhouses identified. RESULTS: In total, seven individuals in three different Canadian provinces became ill following infection with the same outbreak strain of E. coli O157:H7. Two cases were hospitalized and one had severe hemolytic uremic syndrome. No deaths were reported. Two restaurant locations serving different tartare meals including, beef, veal, salmon, tuna, and duck were identified as potential sources of the outbreak. No deficiencies at the restaurant locations were observed during inspections by food inspectors. CONCLUSIONS: The risk of consuming tartare can be lowered when basic hygienic rules are followed, temperature is strictly controlled, and fresh meat is used. However, even if handling, chopping, and temperature control during storage of the meat are considered adequate, tartare is a raw product and the risk of contamination is present. Consumers should be advised that consuming this product can lead to serious illness.

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.

Challenges in listeriosis cluster and outbreak investigations, Province of Quebec, 1997-2011.

OBJECTIVES: Public health authorities place a high priority on investigating listeriosis outbreaks, and these epidemiological investigations remain challenging. Some approaches have been described in the literature to address these challenges. This review of listeriosis clusters and outbreaks investigated in the Province of Quebec (Quebec) highlights investigative approaches that contributed to identifying the source of these outbreaks. MATERIALS: The Laboratoire de Santé Publique du Québec (LSPQ) implemented pulsed-field gel electrophoresis (PFGE) molecular subtyping in 1997 to identify Listeria monocytogenes clusters among isolates from invasive listeriosis cases identified throughout Quebec. A cluster was defined as three cases or more with the same or similar PFGE profiles (≤3 band difference) occurring over a 4-month period. An investigation was initiated if the epidemiologic indicators suggested a common source. Listeriosis data from LSPQ's database were reviewed to identify and describe clusters detected from 1997 to 2011, including those that led to an outbreak investigation. Epidemiological reports prepared following each outbreak were also reviewed. RESULTS: Eleven clusters were identified in the province by LSPQ between 1997 and 2011. Outbreak investigations were initiated for six clusters, four of which involved more than 10 cases. Factors that contributed to identifying the source for three of these outbreaks highlighted the value of (1) making all stakeholders (food safety and inspection services, public health authorities, and laboratories) aware of any ongoing investigation and sharing relevant information even if the source is not yet identified; (2) promptly collecting food samples identified and considered as possible vehicles of infection identified during the interview of a Listeria case; (3) collecting food items and/or environmental samples in locations reported in common by cases in the same cluster. CONCLUSIONS: Multiple approaches should be considered when investigating L. monocytogenes clusters. Networks to facilitate continuous exchange of human and food data between public health and food safety partners should be encouraged.

Multiple outbreaks of gastroenteritis that were associated with 16 funerals and a unique caterer and spanned 6 days, 2011, Québec, Canada.

In January 2011, multiple acute gastroenteritis outbreaks that spanned many days and were related to attendance at funerals were reported to public health units in Quebec. An epidemiological investigation was initiated to identify the source of the contamination and to explain the extent of the contamination over time. Thirty-one cohorts of individuals attended different funerals held between 14 and 19 January. All attendees were served a cold buffet made by the same caterer. Of these 31 cohorts, 16 (with a total of about 800 people) contained individuals who reported being ill after the funeral. Symptoms were mainly diarrhea (89 to 94% of individuals), vomiting (63 to 90%,) and fever (26 to 39%), with a median incubation period of 29 to 33 h and a median duration of symptoms of 24 to 33 h, suggesting norovirus-like infection. Among the 16 cohorts, 3 were selected for cohort studies. Among those three cohorts, the mean illness rate was 68%. Associations were found between those who fell ill and those who had consumed pasta salad (relative risk [RR] = 2.4; P = 0.0022) and ham sandwiches (RR = 1.8; P = 0.0096). No food handlers reported being sick. No stool samples were provided by individuals who became ill. Environmental and food samples were all negative for causative agents. Although the causative agent was not clearly identified, this investigation raised many concerns about the importance of preventing foodborne transmission of viral gastroenteritis and generated some recommendations for management of similar outbreaks.

Escherichia coli O157:H7 outbreak linked to raw milk cheese in Quebec, Canada: use of exact probability calculation and casecase study approaches to foodborne outbreak investigation.

The analytical studies used to investigate foodborne outbreak are mostly case-control or retrospective cohort studies. However, these studies can be complex to perform and susceptible to biases. This article addresses basic principles of epidemiology, probability, and the use of case-case design to identify the source of an Escherichia coli O157:H7 outbreak linked to raw milk cheese consumption in Quebec, Canada; a small number of cases with the same pulsed-field gel electrophoresis (PFGE) profile were involved. Between 4 December 2008 and 15 January 2009, a cumulative total of 16 E. coli O157:H7 cases with the same PFGE profile were reported to Quebec public health authorities. Among the first six cases reported, three had consumed raw milk cheese from the same producer (cheese A). Raw milk cheese is consumed by about 2 % of the Quebec population. By using the exact probability calculation, it was found that a significantly higher proportion of E. coli O157:H7 cases (with the specific PFGE profile) than expected had consumed cheese A (P < 0.001). These computations were updated during the course of the investigation to include subsequent cases and gave the same results. A case-case study corroborated this result. This article considers alternative statistical and epidemiological approaches to investigate a foodborne outbreak-in particular with an exact probability calculation and case-case comparisons. This approach could offer a fast and inexpensive alternative to regular case-control studies to target public health actions, particularly during a foodborne outbreak.

Widespread listeriosis outbreak attributable to pasteurized cheese, which led to extensive cross-contamination affecting cheese retailers, Quebec, Canada, 2008.

A major Listeria monocytogenes outbreak occurred in the province of Quebec, Canada, in 2008, involving a strain of L. monocytogenes (LM P93) characterized by pulsed-field gel electrophoresis (PFGE) and associated with the consumption of pasteurized milk cheese. This report describes the results of the ensuing investigation. All individuals affected with LM P93 across the province were interviewed with a standardized questionnaire. Microbiological and environmental investigations were conducted by the Quebec's Food Inspection Branch of Ministère de l'Agriculture, des Pêcheries et de l'Alimentation du Québec among retailers and cheese plants involved in the outbreak. Between 8 June and 31 December 2008, 38 confirmed cases of LM P93 were reported to public health authorities, including 16 maternal-neonatal cases (14 pregnant women, and two babies born to asymptomatic mothers). The traceback of many brands of cheese that tested positive for LM P93 collected from retailers identified two cheese plants contaminated by L. monocytogenes strains on 3 and 4 September. PFGE profiles became available for both plants on 8 September, and confirmed that a single plant was associated with the outbreak. Products from these two plants were distributed to more than 300 retailers in the province, leading to extensive cross-contamination of retail stock. L. monocytogenes is ubiquitous, and contamination can occur subsequent to heat treatment, which usually precedes cheese production. Contaminated soft-textured cheese is particularly prone to bacterial growth. Ongoing regulatory and industry efforts are needed to decrease the presence of Listeria in foods, including pasteurized products. Retailers should be instructed about the risk of cross-contamination, even with soft pasteurized cheese and apply methods to avoid it.

Epidemiological patterns and hospital characteristics associated with increased incidence of Clostridium difficile infection in Quebec, Canada, 1998-2006.

OBJECTIVE: To explore epidemiological patterns of the incidence of Clostridium difficile infection (CDI) and hospital characteristics associated with increased incidence during nonepidemic and epidemic years. DESIGN: Retrospective and prospective ecological study. SETTING: Eighty-three acute care hospitals participating in CDI surveillance in the province of Quebec, Canada. METHODS: A Serfling-type regression model applied to data obtained from an administrative database (1998-2006) and prospective Quebec CDI surveillance (2004-2006) was used to calculate expected CDI baseline incidence and to detect incidence exceeding the defined epidemic threshold at the provincial and hospital level. Multivariable Poisson regression was used to determine hospital characteristics associated with increased incidence during nonepidemic (1998-2001) and epidemic (2003-2005) periods. RESULTS: During the study period (1998-2006), 4,525,847 discharges, including 45,508 with a CDI in any diagnosis field, were reported by 83 hospitals. During 1998-2001, the average Quebec incidence of CDI was 10,304 cases in 1,775,822 discharges (5.8 cases per 1,000 discharges) and presented a pattern of seasonality, with similar patterns at the hospital level for some hospitals. The Quebec epidemic started in October-November 2002 and peaked in March 2004 at 845 cases in 40,852 discharges (20.7 cases per 1,000 discharges). In multivariable analysis, higher incidence was associated with location in Montreal and surrounding regions, greater hospital size, larger proportion of hospitalized elderly patients, longer length of stay, and greater proportion of comorbidities in patients, whereas teaching profile was associated with decreased incidence during both nonepidemic and epidemic periods. The effect of geographical location on incidence was greater during the epidemic. CONCLUSION: Baseline incidence from nonepidemic years and hospital characteristics associated with CDI incidence should be taken into account when estimating the efficacy of interventions.

Sporadic infections of Salmonella Paratyphi B, var. Java associated with fish tanks.

OBJECTIVE: Identify a source of contamination to explain the increase in the number of cases of S. Paratyphi B var. Java infection. METHOD: A descriptive study was conducted to gather more information about cases and potential risk factors for infection. Between January 2000 and June 2003, we identified and interviewed by questionnaire 53 people with S. Paratyphi B infection. Due to the suspected link with fish tanks, an environmental investigation was conducted for each case at patients' homes as well as at pet stores and wholesalers. Various samples were taken from fish tanks. The fish were purchased at different pet shops. The pulsed field gel electrophoresis method was used to compare the human and aquarium strains. RESULTS: Of those infected, 60% had bought or had contact with an aquarium or tropical fishes before becoming ill. More than 50% of the samples taken from fish tanks in homes, pet shops, and wholesaler operations contained a number of serotypes of Salmonella in addition to Salmonella Paratyphi B var. Java. There were similarities between the PFGE patterns of human strains and aquarium samples. DISCUSSION: Contact with fish tanks could be a risk factor for developing a Salmonella infection and the public may be unaware of this risk. It was recommended that information be produced and distributed to pet shops and their customers to inform them of safety precautions in order to reduce the risk of contamination from bacterial pathogens that may be present in aquarium water.

An outbreak of Bacillus cereus implicating a part-time banquet caterer.

CONTEXT AND OBJECTIVES: In the aftermath of a party, 70% (25 of 36) of attendees had gastroenteritis. The objectives of this study were to identify a risk factor associated with the food during the banquet and to identify measures of control for avoiding this kind of outbreak in the future. METHOD: A retrospective cohort study was used. We tried to reach by telephone all guests who had attended this banquet. A standardized questionnaire was used to provide information about identification of a risk factor, especially in relation to food. RESULTS: The cohort study has shown that potato salad served at the party was significantly associated with the disease. The mayonnaise used to prepare the salad was analyzed and Bacillus cereus was isolated (10(3) bacteria per gram). DISCUSSION: Bacillus microorganisms are usually found in decaying organic matter, dust, soil, vegetables and water. The bacteria has a remarkable ability to survive strong environmental stresses. There are strains of B. cereus that can cause food poisoning episodes with infective doses as low as 10(3) to 10(4) bacteria per gram. B. cereus is an infrequently reported cause of foodborne illnesses in Quebec and in North America but this may be due to underreporting of episodes. In this outbreak, bacterial multiplication was facilitated at several points in the interval between the preparation of the meal and the consumption of the banquet by the guests. Because the spores are ubiquitous and resistant to inactivation with most food grade disinfectants, temperature control should be the main focus of B. cereus outbreak prevention. CONCLUSION: The meal was prepared by a restaurateur who was inexperienced in catering services and temperature control in particular when food is served outside the restaurant. This outbreak underscores the importance of maintaining meticulous hygienic procedures in food processing. Restaurateurs who offer catering services should be familiar with the constraints that are specific to this sector of the food industry.

Travel agents and the prevention of health problems among travelers in Québec.

BACKGROUND: Among the factors influencing travelers to seek preventive health advice before departure, the travel agent's recommendation plays an important role. The objective of our study was to document the practices and needs of travel agents in Québec (Canada) in relation to the prevention of health problems among travelers. METHODS: In June 2000, a cross-sectional descriptive survey was carried out among travel agents from all travel agencies in Québec. One agent per agency was asked to answer our questions. Data were collected using a 32-item telephone questionnaire. RESULTS: Altogether, 708 travel agents from the 948 agencies contacted answered our questionnaire (participation rate: 75%). Most respondents (81%) believed that the travel agent has a role to play in the prevention of health problems among travelers, especially to recommend that travelers consult a travel clinic before departure. Although over 80% of the agents interviewed mentioned recommending a visit to a travel clinic before an organized tour to Thailand or a backpacking trip in Mexico, less than half said they make the same recommendation for a stay in a seaside resort in Mexico. The majority of respondents were acquainted with the services offered in travel health clinics, and these clinics were the source of travel health information most often mentioned by travel agents. However, nearly 60% of the agents questioned had never personally consulted a travel clinic. When asked about the best way to receive information about travelers' health, more than 40% of respondents favoured receiving information newsletters from public health departments regularly whereas 28% preferred the Internet. CONCLUSION: Despite the limits of this study, our results should help the public health network better target its interventions aimed to inform travel agents on prevention of health problems among travelers.