Epidemiology of enteric disease in C-EnterNet's pilot site - Waterloo region, Ontario, 1990 to 2004

Food hygiene knowledge and behaviour among domestic food handlers during COVID 19 pandemic in Bangladesh

The COVID-19 pandemic reshaped every aspect of life, including food safety. Understanding food safety behaviour at home is necessary for developing effective strategies to mitigate foodborne disease during and after this pandemic. This study administered a cross-sectional survey among 503 domestic food handlers to examine the food handlers' food safety concerns during the pandemic and pandemic-related knowledge and hygiene behaviour (PRKHB) in Bangladesh. The results found that only 35.8% of respondents in this study were more concerned about food safety because of the COVID-19 pandemic. Although the results found a good PRKHB among 95.8% of urban food handlers, overall, 62% showed a poor level of PRKHB. Only 38.8% reported washing their hands after returning home or preparing meals every time. The regression model found that food safety concerns positively related to the PRKHB, and participants who lived in rural areas had a negative association with the PRKHB. The study also explored sociodemographic variations and significant differences observed between urban and rural areas. Meticulous educational campaigns and targeted messages to the food handlers on food safety risks, food handling practices and hand hygiene are necessary to minimise the foodborne disease burden in this region.

Background prevalence of subclinical Shiga toxin-producing Escherichia coli in children attending childcare facilities in the Irish Midlands

BACKGROUND

Exclusion of asymptomatic shedders of Shiga toxin-producing Escherichia coli (STEC) from childcare facilities (CCFs) is a recognized measure to minimize risk of secondary transmission. This is predicated on factors including an assumption of low background prevalence of STEC amongst CCF attendees. There is a paucity of scientific evidence regarding the true prevalence of STEC in paediatric populations. The study aimed to develop and test a methodology to estimate background prevalence of STEC amongst CCF attendees at regional level in Ireland.

METHODS

Computerized Infectious Disease Reporting data were used to compile a list of outbreaks of STEC occurring in CCFs in the Irish Midlands since the introduction of polymerase chain reaction (PCR)-based testing. Laboratory data were used to determine background prevalence of STEC in screened children in each outbreak individually and across all outbreaks.

RESULTS

A pooled summary prevalence estimate of 2.9% (95% confidence interval 1.4-5.5%) was determined for the entire screened cohort across all outbreaks. Sensitivity analysis supported the validity of the estimate.

CONCLUSIONS

The relatively high prevalence estimate of 2.9% suggests that a public health risk assessment approach to return of prolonged asymptomatic shedders to the CCF may be appropriate in peak STEC season in the Midlands.

Distribution of heavy metal resistance elements in Canadian Salmonella 4,[5],12:i:- populations and association with the monophasic genotypes and phenotype

Salmonella 4,[5],12:i:- are monophasic S. Typhimurium variants incapable of producing the second-phase flagellar antigen. They have emerged since the mid-1990s to become one of the most prevalent Salmonella serotypes causing human disease world-wide. Multiple genetic events associated with different genetic elements can result in the monophasic phenotype. Several jurisdictions have reported the emergence of a Salmonella 4,[5],12:i:- clone with SGI-4 and a genetic element (MREL) encoding a mercury resistance operon and antibiotic resistance loci that disrupts the second phase antigen region near the iroB locus in the Salmonella genome. We have sequenced 810 human and animal Canadian Salmonella 4,[5],12:i:- isolates and determined that isolates with SGI-4 and the mercury resistance element (MREL; also known as RR1&RR2) constitute several global clades containing various proportions of Canadian, US, and European isolates. Detailed analysis of the data provides a clearer picture of how these heavy metal elements interact with bacteria within the Salmonella population to produce the monophasic phenotype. Insertion of the MREL near iroB is associated with several deletions and rearrangements of the adjacent flaAB hin region, which may be useful for defining human case clusters that could represent outbreaks. Plasmids carrying genes encoding silver, copper, mercury, and antimicrobial resistance appear to be derived from IS26 mediated acquisition of these genes from genomes carrying SGI-4 and the MREL. Animal isolates with the mercury and As/Cu/Ag resistance elements are strongly associated with porcine sources in Canada as has been shown previously for other jurisdictions. The data acquired in these investigations, as well as from the extensive literature on the subject, may aid source attribution in outbreaks of the organism and interventions to decrease the prevalence of this clone and reduce its impact on human disease.

Identifying the environmental drivers of Campylobacter infection risk in southern Ontario, Canada using a One Health approachs

BACKGROUND

Campylobacter bacteria infect both humans and animals. Sources of human exposure include contaminated food and water, contact with animals and/or their faeces, and contact with infected individuals. The objectives of this study were to: (a) identify environmental conditions associated with the occurrence of Campylobacter in humans in four regions of Ontario, and (b) identify pooled measures of effect across all four regions and potential sources of heterogeneity.

METHODS

To address objective 1, human Campylobacter cases from four health regions of Ontario, Canada were analysed using negative binomial regression and case cross-over analysis to identify relationships between environmental factors (temperature, precipitation and hydrology of the local watershed) and the risk of human infection. To address objective 2, meta-analytic models were used to explore pooled measures of effect and when appropriate, meta-regression models were used to explore potential sources of heterogeneity.

RESULTS

Human incidence exhibited strong seasonality with cases peaking in the late spring and summer. There was a decreasing yearly effect in three of the four health regions. A significant pooled effect was found for mean temperature after a 1-week lag (OR = 1.03, 95% CI 1.02, 1.04). No significant pooled effects were found for precipitation or water flow. However, increased precipitation was associated with lower odds of campylobacteriosis in Wellington and York regions at 2- and 3-week lags, respectively, from the case cross-over analysis.

CONCLUSION

These results demonstrate that a climatic factor (specifically, mean temperature in the week prior) was associated with human case occurrence after a biologically plausible time period, but hydrologic factors are not.

Estimates of healthcare utilisation and deaths from waterborne pathogen exposure in Ontario, Canada

Burden of disease analyses can quantify the relative impact of different exposures on population health outcomes. Gastroenteritis where the causative pathogen was not determined and respiratory illness resulting from exposure to opportunistic pathogens transmitted by water aerosols have not always been considered in waterborne burden of disease estimates. We estimated the disease burden attributable to nine enteric pathogens, unspecified pathogens leading to gastroenteritis, and three opportunistic pathogens leading primarily to respiratory illness, in Ontario, Canada (population ~14 million). Employing a burden of disease framework, we attributed a fraction of annual (year 2016) emergency department (ED) visits, hospitalisations and deaths to waterborne transmission. Attributable fractions were developed from the literature and clinical input, and unattributed disease counts were obtained using administrative data. Our Monte Carlo simulation reflected uncertainty in the inputs. The estimated mean annual attributable rates for waterborne diseases were (per 100 000 population): 69 ED visits, 12 hospitalisations and 0.52 deaths. The corresponding 5th–95th percentile estimates were (per 100 000 population): 13–158 ED visits, 5–22 hospitalisations and 0.29–0.83 deaths. The burden of disease due to unspecified pathogens dominated these rates: 99% for ED visits, 63% for hospitalisations and 40% for deaths. However, when a causative pathogen was specified, the majority of hospitalisations (83%) and deaths (97%) resulted from exposure to the opportunistic pathogens Legionella spp., non-tuberculous mycobacteria and Pseudomonas spp. The waterborne disease burden in Ontario indicates the importance of gastroenteritis not traced back to a particular pathogen and of opportunistic pathogens transmitted primarily through contact with water aerosols.

Human campylobacteriosis: A public health concern of global importance

Campylobacter species are among the leading cause of bacterial foodborne and waterborne infections. In addition, Campylobacter is one of the major causative agent of bacterial gastrointestinal infections and the rise in the incidence of Campylobacter infections have been reported worldwide. Also, the emergence of some Campylobacter species as one of the main causative agent of diarrhea and the propensity of these bacteria species to resist the actions of antimicrobial agents; position them as a serious threat to the public health. This paper reviews Campylobacter pathogenicity, infections, isolation and diagnosis, their reservoirs, transmission pathways, epidemiology of Campylobacter outbreaks, prevention and treatment option, antibiotics resistance and control of antibiotics use.

The Influence of Climate and Livestock Reservoirs on Human Cases of Giardiasis

Giardia duodenalis is an intestinal parasite which causes diarrhoeal illness in people. Zoonotic subtypes found in livestock may contribute to human disease occurrence through runoff of manure into multi-use surface water. This study investigated temporal associations among selected environmental variables and G. duodenalis occurrence in livestock reservoirs on human giardiasis incidence using data collected in the Waterloo Health Region, Ontario, Canada. The study objectives were to: (1) evaluate associations between human cases and environmental variables between 1 June 2006 and 31 December 2013, and (2) evaluate associations between human cases, environmental variables and livestock reservoirs using a subset of this time series, with both analyses controlling for seasonal and long-term trends. Human disease incidence exhibited a seasonal trend but no annual trend. A Poisson multivariable regression model identified an inverse association with water level lagged by 1 month (IRR = 0.10, 95% CI 0.01, 0.85, P < 0.05). Case crossover analysis found varying associations between lagged variables including livestock reservoirs (1 week), mean air temperature (3 weeks), river water level (1 week) and flow rate (1 week), and precipitation (4 weeks). This study contributes to our understanding of epidemiologic relationships influencing human giardiasis cases in Ontario, Canada.

Modelling the transmission dynamics of Campylobacter in Ontario, Canada, assuming house flies, Musca domestica, are a mechanical vector of disease transmission

Campylobacter's complicated dynamics and multiple transmission routes have made it difficult to describe using a mathematical framework. Vector-borne disease transmission has been proposed as a potential transmission route of Campylobacter with house flies acting as a mechanical vector. This study aimed to (i) determine if a basic SIR compartment model that included flies as a mechanical vector and incorporated a seasonally forced environment compartment could be used to capture the observed disease dynamics in Ontario, Canada, and (ii) use this model to determine potential changes to campylobacteriosis incidence using predicted changes to fly population size and fly activity under multiple climate change scenarios. The model was fit to 1 year of data and validated against 8 and 12 years of data. It accurately captured the observed incidence. We then explored changes in human disease incidence under multiple climate change scenarios. When fly activity levels were at a 25% increase, our model predicted a 28.15% increase in incidence by 2050 using the medium-low emissions scenario and 30.20% increase using the high emissions scenario. This model demonstrates that the dynamics of Campylobacter transmission can be captured by a model that assumes that the primary transmission of the pathogen occurs via insect vectors.

The need for community-led, integrated and innovative monitoring programmes when responding to the health impacts of climate change

In Northern Canada, climate change has led to many acute and interrelated health and environmental impacts experienced among Inuit populations. Community-based monitoring, in which community members participate in monitoring initiatives using various forms of technology, is a key strategy increasingly used to detect, monitor and respond to climate change impacts. To better understand the landscape of existing environmental and health monitoring programmes mobilising different technologies and operating in the North we conducted a review that used environmental scan methodologies to explore and contextualise these programmes. We consulted with academic researchers with experience in community-led monitoring, conducted systematic searches of grey and peer-reviewed literature, and conducted a secondary search for environment-health mobile-phone applications. Following specific criteria, we identified 18 monitoring programmes using information and communication technologies in the North, and three global monitoring mobile-phone applications, which cumulatively monitored 74 environment and health indicators. Several themes emerged, including the need for: (1) community leadership, (2) indicators of environment and/or human health and (3) innovative technology. This synthesis supports the development of community-led, environment-health monitoring programmes that use innovative technology to monitor and share information related to the health implications of climate change in and around Indigenous communities throughout the Circumpolar North.

Estimated Annual Deaths, Hospitalizations, and Emergency Department and Physician Office Visits from Foodborne Illness in Ontario

Public Health Ontario is working to estimate the burden of disease from environmental hazards in Ontario, Canada. As part of this effort, we estimated deaths and health care utilization resulting from exposure to pathogens and toxic substances in food. We applied fractions for the proportion of illness attributable to foodborne transmission to the annual (2008–2012) counts of deaths, hospitalizations, emergency department (ED) visits, and physician office visits for 15 diseases (13 pathogen-specific diseases and 2 nonspecific syndromes) captured by administrative health data. Nonspecific gastroenteritis (causative agent unknown) was the dominant disease, accounting for 98% of ED visits, 94% of hospitalizations, and 88% of deaths annually attributed to the 15 diseases. We estimated that foodborne nonspecific gastroenteritis results in ∼137,000 physician office visits (1000/100,000 population), 40,000 ED visits (310/100,000), 6200 hospitalizations (47/100,000), and 59 deaths (0.45/100,000) in Ontario per year (mean estimates). Our results indicate that pathogen-specific approaches to foodborne disease surveillance can substantially underestimate the deaths and illness resulting from exposure to foodborne pathogens and other causes of foodborne illness.

Barriers and Facilitators to Safe Food Handling among Consumers: A Systematic Review and Thematic Synthesis of Qualitative Research Studies

Foodborne illness has a substantial health and economic burden on society, and most cases are believed to be due to unsafe food handling practices at home. Several qualitative research studies have been conducted to investigate consumers' perspectives, opinions, and experiences with safe food handling at home, and these studies provide insights into the underlying barriers and facilitators affecting their safe food handling behaviours. We conducted a systematic review of previously published qualitative studies in this area to synthesize the main across-study themes and to develop recommendations for future consumer interventions and research. The review was conducted using the following steps: comprehensive search strategy; relevance screening of abstracts; relevance confirmation of articles; study quality assessment; thematic synthesis of the results; and quality-of-evidence assessment. A total of 39 relevant articles reporting on 37 unique qualitative studies were identified. Twenty-one barriers and 10 facilitators to safe food handling were identified, grouped across six descriptive themes: confidence and perceived risk; knowledge-behaviour gap; habits and heuristics; practical and lifestyle constraints; food preferences; and societal and social influences. Our overall confidence that each barrier and facilitator represents the phenomenon of interest was rated as high (n = 11), moderate (11), and low (9). Overarching analytical themes included: 1) safe food handling behaviours occur as part of a complex interaction of everyday consumer practices and habituation; 2) most consumers are not concerned about food safety and are generally not motivated to change their behaviours based on new knowledge about food safety risks; and 3) consumers are amenable to changing their safe food handling habits through relevant social pressures. Key implications and recommendations for research, policy and practice are discussed.

Campylobacter species in animal, food, and environmental sources, and relevant testing programs in Canada

Campylobacter species, particularly thermophilic campylobacters, have emerged as a leading cause of human foodborne gastroenteritis worldwide, with Campylobacter jejuni, Campylobacter coli, and Campylobacter lari responsible for the majority of human infections. Although most cases of campylobacteriosis are self-limiting, campylobacteriosis represents a significant public health burden. Human illness caused by infection with campylobacters has been reported across Canada since the early 1970s. Many studies have shown that dietary sources, including food, particularly raw poultry and other meat products, raw milk, and contaminated water, have contributed to outbreaks of campylobacteriosis in Canada. Campylobacter spp. have also been detected in a wide range of animal and environmental sources, including water, in Canada. The purpose of this article is to review (i) the prevalence of Campylobacter spp. in animals, food, and the environment, and (ii) the relevant testing programs in Canada with a focus on the potential links between campylobacters and human health in Canada.

A systematic review and meta-analysis of the effectiveness of food safety education interventions for consumers in developed countries

BACKGROUND

Foodborne illness has a large public health and economic burden worldwide, and many cases are associated with food handled and prepared at home. Educational interventions are necessary to improve consumer food safety practices and reduce the associated burden of foodborne illness.

METHODS

We conducted a systematic review and targeted meta-analyses to investigate the effectiveness of food safety education interventions for consumers. Relevant articles were identified through a preliminary scoping review that included: a comprehensive search in 10 bibliographic databases with verification; relevance screening of abstracts; and extraction of article characteristics. Experimental studies conducted in developed countries were prioritized for risk-of-bias assessment and data extraction. Meta-analysis was conducted on data subgroups stratified by key study design-intervention-population-outcome categories and subgroups were assessed for their quality of evidence. Meta-regression was conducted where appropriate to identify possible sources of between-trial heterogeneity.

RESULTS

We identified 79 relevant studies: 17 randomized controlled trials (RCTs); 12 non-randomized controlled trials (NRTs); and 50 uncontrolled before-and-after studies. Several studies did not provide sufficient details on key design features (e.g. blinding), with some high risk-of-bias ratings due to incomplete outcome data and selective reporting. We identified a moderate to high confidence in results from two large RCTs investigating community- and school-based educational training interventions on behaviour outcomes in children and youth (median standardized mean difference [SMD] = 0.20, range: 0.05, 0.35); in two small RCTs evaluating video and written instructional messaging on behavioural intentions in adults (SMD = 0.36, 95% confidence interval [CI]: 0.02, 0.69); and in two NRT studies for university-based education on attitudes of students and staff (SMD = 0.26, 95% CI: 0.10, 0.43). Uncontrolled before-and-after study outcomes were very heterogeneous and we have little confidence that the meta-analysis results reflect the true effect. Some variation in outcomes was explained in meta-regression models, including a dose effect for behaviour outcomes in RCTs.

CONCLUSIONS

In controlled trials, food safety education interventions showed significant effects in some contexts; however, many outcomes were very heterogeneous and do not provide a strong quality of evidence to support decision-making. Future research in this area is needed using more robust experimental designs to build on interventions shown to be effective in uncontrolled before-and-after studies.

Area-level global and local clustering of human Salmonella Enteritidis infection rates in the city of Toronto, Canada, 2007-2009

BACKGROUND

Salmonella enterica serotype Enteritidis (S. Enteritidis) remains a major foodborne pathogen in North America yet studies examining the spatial epidemiology of salmonellosis in urban environments are lacking. Our ecological study combined a number of spatial statistical methods with a geographic information system to assess area-level heterogeneity of S. Enteritidis infection rates in the city of Toronto.

METHODS

Data on S. Enteritidis infections between January 1, 2007 and December 31, 2009 were obtained from Ontario's surveillance system, and were grouped and analyzed at the forward sortation area (FSA)-level (an area signified by the first three characters of the postal code). Incidence rates were directly standardized using the FSA-level age- and sex-based standard population. A spatial empirical Bayes method was used to smooth the standardized incidence rates (SIRs). Global clustering of FSAs with high or low non-smoothed SIRs was evaluated using the Getis-Ord G method. Local clustering of FSAs with high, low, or dissimilar non-smoothed SIRs was assessed using the Getis-Ord Gi* and the Local Moran's I methods.

RESULTS

Spatial heterogeneity of S. Enteritidis infection rates was detected across the city of Toronto. The non-smoothed FSA-level SIRs ranged from 0 to 16.9 infections per 100,000 person-years (mean = 6.6), whereas the smoothed SIRs ranged from 2.9 to 11.1 (mean = 6.3). The global Getis-Ord G method showed significant (p ≤ 0.05) maximum spatial clustering of FSAs with high SIRs at 3.3 km. The local Getis-Ord Gi* method identified eight FSAs with significantly high SIRs and one FSA with a significantly low SIR. The Local Moran's I method detected five FSAs with significantly high-high SIRs, one FSA with a significantly low-low SIR, and four significant outlier FSAs (one high-low, and three low-high).

CONCLUSIONS

Salmonella Enteritidis infection rates clustered globally at a small distance band, suggesting clustering of high SIRs in small distinct areas. This finding was supported by the local cluster analyses, where distinct FSAs with high SIRs, mainly in downtown Toronto, were detected. These areas should be evaluated by future studies to identify risk factors of disease in order to implement targeted prevention and control programs. We demonstrated the usefulness of combining several spatial statistical techniques with a geographic information system to detect geographical areas of interest for further study, and to evaluate spatial processes that influenced S. Enteritidis infection rates. Our study methodology could be applied to other foodborne disease surveillance data.

Spatial and temporal variation in the association between temperature and salmonellosis in NZ

OBJECTIVE

Modelling the relationship between weather, climate and infectious diseases can help identify high-risk periods and provide understanding of the determinants of longer-term trends. We provide a detailed examination of the non-linear and delayed association between temperature and salmonellosis in three New Zealand cities (Auckland, Wellington and Christchurch).

METHODS

Salmonella notifications were geocoded to the city of residence for the reported case. City-specific associations between weekly maximum temperature and the onset date for reported salmonella infections (1997-2007) were modelled using non-linear distributed lag models, while controlling for season and long-term trends.

RESULTS

Relatively high temperatures were positively associated with infection risk in Auckland (n=3,073) and Christchurch (n=880), although the former showed evidence of a more immediate relationship with exposure to high temperatures. There was no significant association between temperature and salmonellosis risk in Wellington.

CONCLUSIONS

Projected increases in temperature with climate change may have localised health impacts, suggesting that preventative measures will need to be region-specific. This evidence contributes to the increasing concern over the public health impacts of climate change.

Global Epidemiology of Campylobacter Infection

Campylobacter jejuni infection is one of the most widespread infectious diseases of the last century. The incidence and prevalence of campylobacteriosis have increased in both developed and developing countries over the last 10 years. The dramatic increase in North America, Europe, and Australia is alarming, and data from parts of Africa, Asia, and the Middle East indicate that campylobacteriosis is endemic in these areas, especially in children. In addition to C. jejuni, there is increasing recognition of the clinical importance of emerging Campylobacter species, including Campylobacter concisus and Campylobacter ureolyticus. Poultry is a major reservoir and source of transmission of campylobacteriosis to humans. Other risk factors include consumption of animal products and water, contact with animals, and international travel. Strategic implementation of multifaceted biocontrol measures to reduce the transmission of this group of pathogens is paramount for public health. Overall, campylobacteriosis is still one of the most important infectious diseases that is likely to challenge global health in the years to come. This review provides a comprehensive overview of the global epidemiology, transmission, and clinical relevance of Campylobacter infection.

Using environmental health officers' opinions to inform the source attribution of enteric disease: further analysis of the "most likely source of infection"

Background

Policies and programs are needed to mitigate the burden of enteric disease in Canada. Source attribution, a goal of FoodNet Canada, can inform such strategies and can be accomplished with the information provided by expert opinion. This includes environmental health officers’ (EHOs) opinions on the “most likely source of infection” (MLSI) of confirmed cases of enteric disease that are investigated by the Fraser Health Authority in British Columbia, FoodNet Canada’s second sentinel site.

Methods

Exposure data from the MLSI were categorized into ten groups and summarized for five enteric disease groups using endemic cases in the first analysis, and a combination of endemic and international travel cases for the second analysis. An exploratory analysis was also conducted on risk setting information in the MLSI. The final analysis involved using a logistic regression model (Wald test) to describe the inherent biases in the data.

Results

Exposure proportions, by disease group, were similar to those of an analysis of MLSI data from FoodNet Canada’s Ontario sentinel site. Food exposure represented the greatest proportion of overall enteric disease (32.0%), as well as for salmonellosis (45.0%), verotoxigenic E. coli (VTEC) infection (38.1%), and campylobacteriosis (30.0%) cases. The majority of parasitic diseases (41.2%) were attributed to water exposure. Food safety practices and consuming unpasteurized products were more frequently reported for campylobacteriosis (19.7% and 5.4%, respectively) compared to other enteric diseases. More VTEC infection was attributed to domestic travel (4.8%) than the other enteric diseases. Among endemic and international travel-related cases combined, VTEC infection was attributed more to endemic food exposure (35.5%) than international travel (16.1%), but similar proportions of campylobacteriosis were attributed to endemic food exposure (25.1%) and international travel (25.1%). Variations existed in the exposure and risk setting information that EHOs included in the MLSI, and in their propensity to enter food sources over other types of exposures.

Conclusions

Results from the MLSI analysis for exposure, risk setting, and EHO bias, are valid contributions for informing source attribution. Important considerations from this work, including strategies to standardize and improve the quality of MLSI data, will enhance source attribution hypotheses.

Stool submission data to help inform population-level incidence rates of enteric disease in a Canadian community

Laboratory-based surveillance data is essential for monitoring trends in the incidence of enteric disease. Current Canadian human enteric surveillance systems report only confirmed cases of human enteric disease and are often unable to capture the number of negative test results. Data from 9116 hospital stool specimens from the Waterloo Region in Canada, with a mixed urban and rural population of about 500 000 were analysed to investigate the use of stool submission data and its role in reporting bias when determining the incidence of enteric disease. The proportion of stool specimens positive for Campylobacter spp. was highest in the 15-29 years age group, and in the 5-14 years age group for Salmonella spp. and E. coli O157:H7. By contrast, the age-specific incidence rates were highest for all three pathogens in the 0-4 years age group which also had the highest stool submission rate. This suggests that variations in age-specific stool submission rates are influencing current interpretation of surveillance data.

Antimicrobial resistance and antimicrobial use associated with laboratory-confirmed cases of Campylobacter infection in two health units in Ontario

AIM

A population-based study was conducted over a two-year period in the Perth District (PD) and Wellington-Dufferin-Guelph (WDG) health units in Ontario to document antimicrobial resistance and antimicrobial use associated with clinical cases of laboratory-confirmed campylobacteriosis.

METHODS

Etest (bioMérieux SA, France) was used to determine the minimum inhibitory concentration of amoxicillin/clavulanic acid, ampicillin, chloramphenicol, ciprofloxacin (CIP), clindamycin, erythromycin (ERY), gentamicin, nalidixic acid and tetracycline. Data regarding antimicrobial use were collected from 250 cases.

RESULTS

Of the 250 cases, 165 (65.7%) reported staying home or being hospitalized due to campylobacteriosis. Fifty-four per cent of cases (135 of 249) reported taking antimicrobials to treat campylobacteriosis. In 115 cases (51.1%), fecal culture results were not used for treatment decisions because they were not available before the initiation of antimicrobial treatment and/or they were not available before the cessation of symptoms. Of the 250 cases, 124 (49.6%) had available Campylobacter isolates, of which 66 (53.2%) were resistant to at least one of the antimicrobials tested. No resistance to ampicillin, chloramphenicol or gentamicin was found in these isolates. Six isolates (4.8%) were resistant to CIP. Two isolates (1.6%) were resistant to ERY; however, no isolates were resistant to both CIP and ERY.

CONCLUSION

Prudent use practices should be promoted among physicians to reduce the use of antimicrobials for the treatment of gastroenteritis in general and campylobacteriosis in particular, as well as to minimize the future development of resistance to these antimicrobials in Campylobacter species.

Incidence, distribution, seasonality, and demographic risk factors of Salmonella Enteritidis human infections in Ontario, Canada, 2007-2009

BACKGROUND

In Canada, surveillance systems have highlighted the increasing trend of Salmonella enterica serovar Enteritidis (S. Enteritidis) human infections. Our study objectives were to evaluate the epidemiology of S. Enteritidis infections in Ontario using surveillance data from January 1, 2007 through December 31, 2009.

METHODS

Annual age-and-sex-adjusted incidence rates (IRs), annual and mean age-adjusted sex-specific IRs, and mean age-and-sex-adjusted IRs by public health unit (PHU), were calculated for laboratory-confirmed S. Enteritidis cases across Ontario using direct standardization. Multivariable Poisson regression with PHU as a random effect was used to estimate incidence rate ratios (IRRs) of S. Enteritidis infections among years, seasons, age groups, and sexes.

RESULTS

The annual age-and-sex-adjusted IR per 100,000 person-years was 4.4 [95% CI 4.0-4.7] in 2007, and 5.2 [95% CI 4.8-5.6] in both 2008 and 2009. The annual age-adjusted sex-specific IRs per 100,000 person-years ranged from 4.5 to 5.5 for females and 4.2 to 5.2 for males. The mean age-adjusted sex-specific IR was 5.1 [95% CI 4.8-5.4] for females and 4.8 [95% CI 4.5-5.1] for males. High mean age-and-sex-adjusted IRs (6.001-8.10) were identified in three western PHUs, one northern PHU, and in the City of Toronto. Regression results showed a higher IRR of S. Enteritidis infections in 2009 [IRR = 1.18, 95% CI 1.06-1.32; P = 0.003] and 2008 [IRR = 1.17, 95% CI 1.05-1.31; P = 0.005] compared to 2007. Compared to the fall season, a higher IRR of S. Enteritidis infections was observed in the spring [IRR = 1.14, 95% CI 1.01-1.29; P = 0.040]. Children 0-4 years of age (reference category), followed by children 5-9 years of age [IRR = 0.64, 95% CI 0.52-0.78; P < 0.001] had the highest IRRs. Adults ≥ 60 years of age and 40-49 years of age [IRR = 0.31, 95% CI 0.26-0.37; P < 0.001] had the lowest IRRs.

CONCLUSIONS

The study findings suggest that there was an increase in the incidence of S. Enteritidis infections in Ontario from 2007 to 2008-2009, and indicate seasonal, demographic, and regional differences, which warrant further public health attention.

A descriptive study of reportable gastrointestinal illnesses in Ontario, Canada, from 2007 to 2009

Background

Gastrointestinal illnesses (GI) continue to pose a substantial burden in terms of morbidity and economic impact in Canada. We describe the epidemiology of reportable GI in Ontario by characterizing the incidence of each reportable GI, as well as associated demographics, clinical outcomes, seasonality, risk settings, and likely sources of infection.

Methods

Reports on laboratory confirmed cases of amebiasis, botulism, campylobacteriosis, cryptosporidiosis, cyclosporiasis, giardiasis, hepatitis A, listeriosis, paratyphoid fever, salmonellosis, shigellosis, typhoid fever, illness due to verotoxin-producing Escherichia coli (VTEC-illness), and yersiniosis, from January 1, 2007 to December 31, 2009 were obtained from Ontario’s passive reportable disease surveillance system. Cases were classified by history of relevant travel, association with outbreaks, and likely source of infection, obtained through follow-up of reported cases by local health authorities.

Results

There were 29,897 GI reported by health authorities in Ontario from 2007 to 2009. The most frequently reported diseases were campylobacteriosis (10,916 cases or 36.5% of all GI illnesses) and salmonellosis (7,514 cases, 25.1%). Overall, 26.9% of GI cases reported travel outside of Ontario during the relevant incubation period. Children four years of age and younger had the highest incidence rate for most GI, and significantly more (54.8%, p<0.001) cases occurred among males than females. The most commonly reported sources of infections were food (54.2%), animals (19.8%), and contact with ill persons (16.9%). Private homes (45.5%) and food premises (29.7%) were the most commonly reported exposure settings. Domestic cases of campylobacteriosis, cryptosporidiosis, giardiasis, salmonellosis, and VTEC-illness showed seasonal patterns with incidence peaking in the summer months.

Conclusions

Reportable GI continues to be a burden in Ontario. Since more than one in four GI cases experienced in Ontario were acquired outside of the province, international travel is an important risk factor for most GI. Because private homes are the most commonly reported risk settings and the main suspect sources of infection are food, animal contact and ill persons, these findings support the continued need for public health food safety programs, public education on safe handling of food and animals, and proper hand hygiene practices.

Epidemiological and clinical description of the top three reportable parasitic diseases in a Canadian community

This study provides a comprehensive epidemio-clinical picture of sporadic, domestically acquired cases of amoebiasis, cryptosporidiosis and giardiasis in one Canadian community based on patient symptom, outcome and exposure data from an enhanced surveillance system. It yields valuable data for estimating the burden of those diseases including the proportion of bloody diarrhoea, hospitalization, and disease duration. Age differences were observed by incidence rate and for some clinical information and exposures to risk factors. For each of the three diseases, the animal/environment-to-person route was the most common possible main transmission route according to the exposure reported, whereas the person-to-person route was the least common. Exposure was higher for the 10–24 years age group of giardiasis cases for swimming in recreational waters (79%) and attending a barbeque (50%). Therefore, comparisons between groups of cases or extrapolation of results when estimating the burden of illness should be adjusted for age.

Seasonality in human zoonotic enteric diseases: a systematic review

Background

Although seasonality is a defining characteristic of many infectious diseases, few studies have described and compared seasonal patterns across diseases globally, impeding our understanding of putative mechanisms. Here, we review seasonal patterns across five enteric zoonotic diseases: campylobacteriosis, salmonellosis, vero-cytotoxigenic Escherichia coli (VTEC), cryptosporidiosis and giardiasis in the context of two primary drivers of seasonality: (i) environmental effects on pathogen occurrence and pathogen-host associations and (ii) population characteristics/behaviour.

Methodology/Principal Findings

We systematically reviewed published literature from 1960–2010, resulting in the review of 86 studies across the five diseases. The Gini coefficient compared temporal variations in incidence across diseases and the monthly seasonality index characterised timing of seasonal peaks. Consistent seasonal patterns across transnational boundaries, albeit with regional variations was observed. The bacterial diseases all had a distinct summer peak, with identical Gini values for campylobacteriosis and salmonellosis (0.22) and a higher index for VTEC (Gini = 0.36). Cryptosporidiosis displayed a bi-modal peak with spring and summer highs and the most marked temporal variation (Gini = 0.39). Giardiasis showed a relatively small summer increase and was the least variable (Gini = 0.18).

Conclusions/Significance

Seasonal variation in enteric zoonotic diseases is ubiquitous, with regional variations highlighting complex environment-pathogen-host interactions. Results suggest that proximal environmental influences and host population dynamics, together with distal, longer-term climatic variability could have important direct and indirect consequences for future enteric disease risk. Additional understanding of the concerted influence of these factors on disease patterns may improve assessment and prediction of enteric disease burden in temperate, developed countries.

The epidemiology of human salmonellosis in New Zealand, 1997–2008

This study describes the epidemiology of human salmonellosis in New Zealand using notified, hospitalized and fatal cases over a 12-year period (1997–2008). The average annual incidence for notifications was 42·8/100 000 population and 3·6/100 000 population for hospitalizations. Incidence was about twice as high in summer as in winter. Rural areas had higher rates than urban areas (rate ratio 1·23, 95% confidence interval 1·22–1·24 for notifications) and a distinct spring peak. Incidence was highest in the 0–4 years age group (154·2 notifications/100 000 and 11·3 hospitalizations/100 000). Hospitalizations showed higher rates for Māori and Pacific Island populations compared to Europeans, and those living in more deprived areas, whereas notifications showed the reverse, implying that notifications are influenced by health-seeking behaviours.SalmonellaTyphimurium was the dominant serotype followed byS. Enteritidis. For a developed country, salmonellosis rates in New Zealand have remained consistently high suggesting more work is needed to investigate, control and prevent this disease.