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The recent emergence of West Nile virus (WNV) in North America highlights vulnerability to climate sensitive diseases and stresses the importance of preventive efforts to reduce their public health impact. Effective prevention involves reducing environmental risk of exposure and increasing adoption of preventive behaviours, both of which depend on knowledge and acceptance of such measures. When making operational decisions about disease prevention and control, public health must take into account a wide range of operational, environmental, social and economic considerations in addition to intervention effectiveness. The current study aimed to identify, assess and rank possible risk reduction measures taking into account a broad set of criteria and perspectives applicable to the management of WNV in Quebec under increasing transmission risk scenarios, some of which may be related to ongoing warming in higher-latitude regions. A participatory approach was used to collect information on categories of concern to relevant stakeholders with respect to WNV prevention and control. Multi-criteria decision analysis was applied to examine stakeholder perspectives and their effect on strategy rankings under increasing transmission risk scenarios. Twenty-three preventive interventions were retained for evaluation using eighteen criteria identified by stakeholders. Combined evaluations revealed that, at an individual-level, inspecting window screen integrity, wearing light colored, long clothing, eliminating peridomestic larval sites and reducing outdoor activities at peak times were top interventions under six WNV transmission scenarios. At a regional-level, the use of larvicides was a preferred strategy in five out of six scenarios, while use of adulticides and dissemination of sterile male mosquitoes were found to be among the least favoured interventions in almost all scenarios. Our findings suggest that continued public health efforts aimed at reinforcing individual-level preventive behaviours combined with the application of larvicides to manage the risk of WNV infection are the interventions most acceptable and effective at reaching current management objectives now and under future theoretical transmission risk.

OBJECTIVES: Despite its extensive use, the termSurveillanceoften takes on various meanings in the scien- tific literature pertinent to public health and animal health. A critical appraisal of this literature also reveals ambiguities relating to the scope and necessary structural components underpinning the surveillance process. The authors hypothesized that these inconsistencies translate to real or perceived deficiencies in the conceptu - al framework of population health surveillance. This paper presents a population health surveillance theory framed upon an explicit conceptual system relative to health surveillance performed in human and animal populations. METHODS: The population health surveillance theory reflects the authors' system of thinking and was based on a creative process. RESULTS: Population health surveillance includes two broad components: one relating to the human organi- zation (which includes expertise and the administrative program), and one relating to the system per se (which includes elements of design and method) and which can be viewed as a process. The population health surveil- lance process is made of five sequential interrelated steps: 1) a trigger or need, 2) problem formulation, 3) sur - veillance planning, 4) surveillance implementation, and 5) information communication and audit. CONCLUSIONS: The population health surveillance theory provides a systematic way of understanding, or- ganizing and evaluating the population health surveillance process.

Veterinary and public health surveillance programs can be evaluated to assess and improve the planning, implementation and effectiveness of these programs. Guidelines, protocols and methods have been developed for such evaluation. In general, they focus on a limited set of attributes (e.g., sensitivity and simplicity), that are assessed quantitatively whenever possible, otherwise qualitatively. Despite efforts at standardization, replication by different evaluators is difficult, making evaluation outcomes open to interpretation. This ultimately limits the usefulness of surveillance evaluations. At the same time, the growing demand to prove freedom from disease or pathogen, and the Sanitary and Phytosanitary Agreement and the International Health Regulations require stronger surveillance programs. We developed a method for evaluating veterinary and public health surveillance programs that is detailed, structured, transparent and based on surveillance concepts that are part of all types of surveillance programs. The proposed conceptual evaluation method comprises four steps: (1) text analysis, (2) extraction of the surveillance conceptual model, (3) comparison of the extracted surveillance conceptual model to a theoretical standard, and (4) validation interview with a surveillance program designer. This conceptual evaluation method was applied in 2005 to C-EnterNet, a new Canadian zoonotic disease surveillance program that encompasses laboratory based surveillance of enteric diseases in humans and active surveillance of the pathogens in food, water, and livestock. The theoretical standard used for evaluating C-EnterNet was a relevant existing structure called the “Population Health Surveillance Theory”. Five out of 152 surveillance concepts were absent in the design of C-EnterNet. However, all of the surveillance concept relationships found in C-EnterNet were valid. The proposed method can be used to improve the design and documentation of surveillance programs. It complements existing surveillance evaluation methods. Conceptual evaluation is not a performance-oriented evaluation method and so it is particularly useful for surveillance programs with a valid conceptual framework but limited technical capacity and resources. Such programs would be penalized using existing performance-based evaluation methods. Applying conjointly the conceptual evaluation along with existing performance-oriented evaluation methods will better judge the worth of surveillance programs. We recommend developing a comprehensive surveillance evaluation framework for veterinary and public health surveillance programs that integrates all existing surveillance evaluation tools and provides an appropriate way to evaluate various types of surveillance programs.

SUMMARYThis 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.

Background Although Campylobacter is the leading cause of reported bacterial gastro-enteritis in industrialized countries, little is known on its recurrence. The objective of this study is to describe the risk and the patient characteristics of recurrent episodes of human campylobacteriosis reported in Quebec. Methods Laboratory-confirmed cases of campylobacteriosis reported in the province of Quebec, Canada, through ongoing surveillance between 1996 and 2006 were analyzed. The risk of having a recurrent episode of campylobacteriosis was described using life table estimates. Logistic regression was used to assess if gender, age and patient residential location were associated with an increased risk of recurrence. Results Compared to the baseline risk, the risk for a recurrent disease event was higher for a period of four years and followed a decreasing trend. This increased risk of a recurrent event was similar across gender, but higher for people from rural areas and lower for children under four years of age. Conclusions These results may suggest the absence of durable immunity or clinical resilience following a first episode of campylobacteriosis and periodical re-exposure, at least among cases reported through the surveillance system.

This study used integrated surveillance data to assess the seasonality in retail chicken contamination and of human activities and their role on the seasonality of human endemic salmonellosis. From June 2005 to May 2008, reported cases of salmonellosis were followed-up comprehensively using a standardized questionnaire, and 616 retail chicken breasts were systematically tested for Salmonella, in one Canadian community. Poisson regression was used to model seasonality of human cases, Salmonella in retail chicken, and to assess the relationship between these and selected meteorological variables. The case-case approach was used to compare the activities of salmonellosis cases that occurred during the summer peak to the other cases. There were 216 human endemic salmonellosis cases (incidence rate: 14.7 cases/100,000 person-years), predominantly of Typhimurium and Enteritidis serotypes (28.4% and 20.8%, respectively). The monthly distribution of cases was associated with ambient temperature (p0.001) with a significant seasonal peak in June (p = 0.03) and July (p = 0.0005), but it was not associated with precipitation (p = 0.38). Several activities reported by cases tended to be more frequent during summer. Particularly, attending a barbeque and gardening within the 3 days before the disease onset were two significant risk factors for salmonellosis in June or July compared with the salmonellosis cases that occurred in the other months. Out of all chicken samples, 185 (30%) tested positive for Salmonella spp., Kentucky being the dominant serotype (44.3% of positive samples). The monthly proportion of positive chicken samples showed no seasonal variations (p = 0.30) and was not associated with the monthly count of human cases (p = 0.99). In conclusion, even though evidence generally supports chicken as a primary vehicle of Salmonella to humans, the contamination of retail chicken was not driving the seasonality in human salmonellosis. Attending a barbeque or gardening during the hotter months of the year should be further assessed for their risk.

Analysis of foodborne outbreak data is one approach to estimate the proportion of human cases of specific enteric diseases attributable to a specific food item (food attribution). Although we recognize that for a variety of reasons reported outbreaks represent only a small portion of all actual outbreaks, using outbreak data for food attribution is the only methodological approach where, theoretically, there is an actual direct link between the pathogen, its source and each infected person. The purpose of this study was to explore the usefulness of foodborne outbreak data extracted from publicly available international electronic reports and publications to provide estimates of food attribution, to derive and compare these estimates between regions, while improving the understanding of the pathogen/food vehicle combination. Electronic reports and publications of foodborne outbreaks that occurred globally since the 1980s were systematically scanned and their data were extracted and compiled in a database. A system of food categorization was developed and food vehicles assigned accordingly. The association between the aetiology and the food source was statistically described for outbreaks with both reported aetiology and incriminated food vehicle. Differences in associations between Australia and New Zealand, Canada, the European Union (EU) and the United States (US) were explored using multiple correspondence analysis and were formally tested between the EU and the US for selected pathogens and food sources. As a result, the food and aetiology cross tabulation of 4093 foodborne outbreaks that occurred globally between 1988 and 2007 is presented and discussed. For a few aetiologies and some foods the association is very specific. The lack of a specific association between the other foods and aetiologies highlights the potential roles of cross-contamination, environmental contamination and the role of the infected foodhandler along the food chain from farm to fork. Detailed analysis of the four regions highlighted some specific associations: Salmonella Enteritidis outbreaks occurred relatively often in the EU states with eggs as the most common source; Campylobacter associated outbreaks were mainly related to poultry products in the EU and to dairy products in the US; there was an association between Escherichia coli outbreaks and beef in Canada; and while Salmonella Typhiumurium outbreaks were relatively common in Australia and New Zealand, across all regions, Salmonella was associated with a variety of food groups. The value and limitations of the study are discussed, as well as the extrapolation of the food attribution estimates beyond their outbreak context.

Porcine proliferative enteropathy caused by Lawsonia intracellularis is an important enteric disease in swine throughout the world. Information regarding the distribution of this pathogen in Canadian swine herds would be beneficial for the creation of control protocols. Pigs from Ontario, Quebec, and Alberta were tested by using an indirect immunofluorescence assay for antibodies to L. intracellularis. Pig seroprevalence was calculated as the proportion of pigs positive from total pigs tested in the targeted population. Seroprevalence (+/- standard error [s(x)]) in market hogs in Ontario from farrow-finish (FF) farms and finishing (FIN) farms were significantly different at 77% (s(x) = 7%) and 29% (s(x) = 15%), respectively. Seroprevalence for sows and gilts in FF and farrowing and nursery (FAR + NUR) farms in Ontario were 90% (s(x) = 3%) and 93% (s(x) = 6%), respectively. Seroprevalence in breeding females in Quebec from FF and FAR farms was 82% (s(x) = 5%) and 87% (s(x) = 3%), respectively. Seroprevalence (57%, s(x) = 8%) in finishing pigs in Alberta from FF farms was significantly different from that of multisite (MS) farms and FIN farms, 6% (s(x) = 6%) and 9% (s(x) = 5%), respectively. Lawsonia intracellularis appears to be widespread in Canada and the seroprevalence on FF farms is higher than that on FIN and MS farms, possibly due to the presence of breeding females or management differences.

In the context of meat inspection modernization, the current mandatory incision and visual inspection of all hog mandibular lymph nodes (MLNs) to detect signs of infection by Mycobacterium bovis, a zoonotic infection is examined. Canadian data of MLN pathology and microbial contamination are scarce and the performance of the current regulatory inspection of MLNs in actually detecting lesions and contamination by Mycobacterium bovis has not been documented. A survey of MLN condition in market hogs according to various inspection schemes was undertaken to fill the data gap. One MLN of a representative sample of 149 483 hogs were submitted to standard pathological and bacteriological analyses. Actual abnormal MLNs actually were rare (below 8%). They are often under detected by the current inspection because of limited sensitivity (18%). Such abnormalities, even undetected, have very limited, if any, impact on human health since the pathological and microbiological analyses failed to provide evidence of Mycobacterium bovis infection. On the other hand, MLNs can be contaminated with several bacteria potentially pathogenic to humans, raising the risk of cross-contamination during the inspection with incision. Finally, the current incision and visual inspection of all hog MLNs and the proposed visual-only inspection perform similarly in identifying abnormal MLNs.

In the context of a risk-based meat inspection modernization, the change towards a visual only inspection of all hog mandibular lymph nodes (MLN) has been made in some countries and is considered in Canada. In fact, the current mandatory incision and visual inspection of all MLNs put in force a century ago to detect signs of infection by Mycobacterium bovis may no longer be relevant and may even generate cross-contamination by bacteria potentially pathogenic to humans. To support a science-based decision, a qualitative risk-benefit assessment following the European Food Safety Authority framework was undertaken for each inspection approach (with or without systematic incision). Both risk-benefit assessments led to similar results in concluding that the benefit of any MLN inspection for the detection of M. bovis infection in hogs is no longer existent. For the risk associated with this incision, data is lacking to differentiate the risk between both inspections on the qualitative scale chosen. In conclusion, the scientific opinion is that the replacement of the current systematic incision and visual inspection of all hog MLNs by a systematic visual-only inspection of all MLNs will not affect the food safety risks and in fact may reduce some of them.

OBJECTIVE:To describe rates of antimicrobial resistance (AMR) amongSalmonellaandShigellaisolates reported in five Canadian provinces, focusing on clinically important antimicrobials.METHODS:The authors retrospectively investigated AMR rates among 6219Salmonellaand 1673Shigellaisolates submitted to provincial public health laboratories in Alberta, Newfoundland and Labrador, Ontario, Prince Edward Island and Saskatchewan from 1997 to 2000; these isolates were estimated to represent 41% ofSalmonellacases and 72% ofShigellacases reported by the study provinces.RESULTS:AmongSalmonellaisolates, 27% (1704 of 6215) were resistant to ampicillin, 2.2% (135 of 6122) to trimethoprim/sulfamethoxazole, 1.5% (14 of 938) to nalidixic acid, 1.2% (one of 84) to lomafloxacin and 0.08% (five of 6163) to ciprofloxacin. AmongShigellaisolates, 70% (1144 of 1643) were resistant to trimethoprim/sulfamethoxazole, 65% (1079 of 1672) to ampicillin, 3.1% (eight of 262) to nalidixic acid, 0.49% (eight of 1636) to ciprofloxacin, 0.14% (one of 700) to ceftriaxone and 0.08% (one of 1292) to ceftazidime.CONCLUSIONS:Higher rates of resistance to clinically important antimicrobials (including ciprofloxacin) were observed among bothSalmonellaandShigellaisolates than has previously been reported. Current Canadian data on rates of AMR for these pathogens are required.

Five protocols were compared to determine the combined effects of different sample weights and culture methods for the recovery of Salmonella from 310 pig cecal samples taken in abattoirs as part of the Canadian Integrated Program for Anti-microbial Resistance Surveillance. Sample weights evaluated were 1 and 10 g. Culture methods used with each sample weight were modified semisolid Rappaport-Vassiliadis agar (MSRV) and brilliant green agar with sulfa and novobiocin (BGSN) and xylose-lysine-tergitol-4 agar (XLT4). A preliminary sample preparation step in saline was also evaluated using a 10-g sample and MSRV. The Salmonella recovery rate varied from 20% for the saline MSRV 10-g protocol to 32% for the MSRV 10-g and the BGSN-XLT4 10-g protocols. A good agreement (K > 0.8) was observed between pairs of protocols except whenever the saline MSRV 10-g and the MSRV 1-g protocols were compared. Larger samples (10 g) yielded higher detection of Salmonella than 1-g samples for the MSRV protocol (32 versus 25%), whereas the differences were not statistically significant for the BGSN-XLT4 protocols. Protocols using the BGSN-XLT4 agar yielded higher detection rates of Salmonella compared with MSRV with 1-g samples (30 versus 25%), whereas it was equivalent with 10-g samples. Considering a greater recovery rate, the ease of use, and a better time and resource efficiency, the MSRV 10-g protocol was therefore adopted by the Canadian Integrated Program for Antimicrobial Resistance Surveillance.

Infections by enteropathogenic microorganisms linked to agroenvironmental contamination represent a significant threat to urban and rural communities. To better characterize and manage this risk, it is necessary, not only to accurately describe enteric illnesses occurring over time or across regions, but also to correctly assess exposure attributable to this environmental pollution. New agroenvironmental hygienic pressure indicators (AHPIs) were developed to synthesise relevant data expressing this exposure. They were derived from a conceptual framework for developing sustainable agriculture indicators and specifically adapted for describing the microbial risk of water contamination by livestock operations. The proposed indicators include two components, and five attributes whose values are calculated at the livestock operation level from a set of available data related to the fields of microbiology, animal production, agronomy, hydrology, and meteorology. They are then aggregated at a higher geographical level to better express exposure of human populations to potential of water contamination by zoonotic enteropathogens. The indicators are calculated separately by zoonotic enteropathogens, and by water source (surface or groundwater). They take into account the various animal species within each livestock operation. When validated, the proposed indicators will allow decision-makers and public health officials to better manage crucial issues in the area of water safety and agriculture.

Assessment in Québec of a french ecopathologic tool designed to investigate postweaning digestive disorders in piglets. This study was designed to assess whether an ecopathologic tool made for the investigation of postweaning digestive disorders in piglets could be used in Québec intensive herds. This French tool allows to determine from 13 variables evaluated on the farm the level of the clinical problems and the level of specific risk factors. The tool was applied in 60 pig randomly selected herds in Québec. For each farm, the 13 variables were measured and the clinical problems and risk levels were determined. Practical and methodological problems are discussed. Some variables are difficult to measure. There are four units of observation all considered as only one. The tool is applied in a static way upon dynamic processes. Moreover, the conditions for its use described by the designers were not met. The distributions of 10 out 13 variables from the Québec data set were significantly different from the French one from which the tool was developed. It was concluded that the echopathological tool cannot be used in Québec., Cette étude avait pour objectif de déterminer l’applicabilité au Québec d’un outil écopathologique français d’investigation des troubles digestifs après le sevrage en élevage porcin intensif. Cet outil détermine le niveau des troubles cliniques et le niveau du risque circonstanciel associé à partir de 13 variables. Il a été appliqué dans 60 élevages québécois choisis au hasard. Pour chacun, la valeur des 13 variables a été mesurée, parfois avec difficulté et les niveaux des troubles et du risque déterminés. Cette présentation discute des problèmes pratiques et méthodologiques liés à l’utilisation de l’outil. Il y a quatre niveaux de mesure tous analysés sur le même plan. De plus, l’outil s’applique de façon statique sur des phénomènes dynamiques. Enfin, la similitude entre l’élevage d’application et les élevages bretons qui ont servi à l’élaboration de l’outil n’a pas été rencontrée. Les distributions de 10 des 13 variables sont significativement différentes entre l’échantillon d’élevages québécois et l’échantillon d’élevages bretons. Comme cette similitude est nécessaire pour appliquer l’outil, celui-ci n’est donc pas utilisable au Québec., Ravel André, Allaire Sylvie d’, Bigras-Poulin Michel, Martineau Guy-Pierre. Applicabilité au Québec d’un outil français d'investigation écopathologique des troubles digestifs après le sevrage en élevage porcin. In: Bulletin de l'Académie Vétérinaire de France tome 144 n°1, 1991. pp. 85-92.

Twenty-four sows (six littermate groups of four sows each) from 29 to 106 kg liveweight were fed either 0 or 8% solvent-extracted rapeseed meal, substituted on an isonitrogenous basis for soybean meal and wheat. The two groups were then subdivided to receive either 0 or 8% rapeseed meal in their diets through two complete reproductive cycles.Average daily gain of gilts fed rapeseed meal was lower throughout the growing period but was significantly depressed only from 90 to 106 kg liveweight. Number of services to conception, gestation weight gains, gestation length and lactation weight losses were not significantly influenced by dietary treatment. In the first reproductive cycle, sows fed rapeseed meal during the growing period farrowed only 0.2 pigs less per litter than those fed the diet containing soybean meal, but weaned 2.5 pigs less which resulted in a reduced litter weaning weight.During the second reproductive cycle, treatment during growth had no significant influence on performance of the sows or litters. Sows fed rapeseed meal during gestation and lactation performed as well during both reproductive cycles as those fed the soybean meal diet. The results indicate that levels of 8% rapeseed meal should not be fed to growing gilts that are to be saved for reproduction.

In spatial epidemiology, the choice of an appropriate geographical unit of analysis is a key decision that will influence most aspects of the study. In this study, we proposed and applied a set of measurable criteria applicable for orienting the choice of geographical unit. Nine criteria were selected, covering many aspects such as biological relevance, communicability of results, ease of data access, distribution of exposure variables, cases and population, and shape of unit. These criteria were then applied to compare various geographical units derived from administrative, health services, and natural frameworks that could be used for the study of the spatial distribution of campylobacteriosis in the province of Quebec, Canada. In this study, municipality was the geographical unit that performed the best according to our assessment and given the specific objectives and time period of the study. Future research areas for optimizing the choice of geographical unit are discussed.

Background Campylobacter is a common cause of bacterial gastro-enteritis characterized by multiple environmental sources and transmission pathways. Ecological studies can be used to reveal important regional characteristics linked to campylobacteriosis risk, but their results can be influenced by the choice of geographical units of analysis. This study was undertaken to compare the associations between the incidence of campylobacteriosis in Quebec, Canada and various environmental characteristics using seven different sets of geographical units. Methods For each set of geographical unit, a conditional autoregressive model was used to model the incidence of reported cases of campylobacteriosis according to environmental (poultry density, ruminant density, slaughterhouse presence, temperature, and precipitation) and demographic (population density, level of education) characteristics. Models were compared in terms of number of significant predictors, differences in direction and magnitude of predictors, and fit of the models. Results In general, the number of significant predictors was reduced as the aggregation level increased. More aggregated scales tend to show larger but less precise estimates for all variables, with the exception of slaughterhouse presence. Regional characteristics associated with an increased regional risk of campylobacteriosis, for at least some geographical units, were high ruminant density, high poultry density, high population density, and presence of a large poultry slaughterhouse, whereas a reduction in risk was associated with a lower percentage of people with diplomas, a lower level of precipitation, and warmer temperature. Two clusters of elevated residual risk were observed, with different location and size depending on the geographical unit used. Conclusions Overall, our results suggest that the use of municipality or census consolidated subdivision were the most optimal scales for studying environmental determinants of campylobacteriosis at a regional level. This study highlights the need for careful selection and analysis of geographical units when using ecological study designs.

Background Lyme disease (LD) is a vector-borne disease that is endemic in many temperate countries, including Switzerland, and is currently emerging in Canada. This study compares the importance of knowledge, exposure and risk perception for the adoption of individual preventive measures, within and between two different populations, one that has been living in a LD endemic region for several decades, the Neuchâtel canton in Switzerland, and another where the disease is currently emerging, the Montérégie region in the province of Québec, Canada. Methods A web-based survey was carried out in both study regions (814 respondents) in 2012. Comparative analysis of the levels of adoption of individual preventive measures was performed and multivariable logistic regression analyses were used to test and compare how knowledge, exposure and risk perception were associated with the adoption of selected measures in both regions and globally. Results In Montérégie, the proportion of reported adoption of five of the most commonly recommended preventive measures varied from 6% for ‘applying acaricides on one’s property’ to 49% for ‘wearing protective clothing’, and in Neuchâtel, proportions ranged from 6% (acaricides) to 77% for ‘checking for ticks (tick check)’. Differences were found within gender, age groups and exposure status in both regions. The perceived efficacy of a given measure was the strongest factor associated with the adoption of three specific preventive behaviors for both regions: tick check, protective clothing and tick repellent. Risk perception and a high level of knowledge about LD were also significantly associated with some of these specific behaviors, but varied by region. Conclusions These results strongly suggest that social and contextual factors such as the epidemiological status of a region are important considerations to take into account when designing effective prevention campaigns for Lyme disease. It furthermore underlines the importance for public health authorities to better understand and monitor these factors in targeted populations in order to be able to implement preventive programs that are well adapted to a population and the epidemiological contexts therein. Electronic supplementary material The online version of this article (doi:10.1186/s12889-015-1539-2) contains supplementary material, which is available to authorized users.