Verotoxigenic Escherichia coli: costs of illness in Canada, including long-term health outcomes.

The main objective of this study was to provide cost estimates of human Escherichia coli O157 infection to facilitate future assessment of the benefits and costs of alternative preventive strategies to reduce illness. We investigated the costs of illness to Canadians from primary human infection by verotoxigenic E. coli O157 (also called Shiga toxin-producing E.

Respiratory symptoms and the case definition of gastroenteritis: an international analysis of the potential impact on burden estimates.

Estimates of the burden of foodborne disease rely on attributing a proportion of syndromic gastroenteritis to foodborne transmission. Persons with syndromic diarrhoea/vomiting can also present with concurrent respiratory symptoms that could be due to respiratory infections, gastrointestinal infections, or both. This distinction is important when estimating the foodborne disease burden but has rarely been considered.

Burden of acute gastrointestinal illness in Canada, 1999-2007: interim summary of NSAGI activities.

Introduction: The National Studies on Acute Gastrointestinal Illness (NSAGI) initiative was designed to generate baseline period prevalence rates of self-reported AGI in communities across Canada, assess the burden associated with AGI, and quantify the under-reporting of AGI in Canada's national enteric disease reporting systems.

Methods: Methods utilized included population surveys administered randomly via telephone services. Three population surveys in three locations within Canada included over 10,000 residents.

Estimation of the costs of acute gastrointestinal illness in British Columbia, Canada.

The costs associated with gastrointestinal infection (GI) in the province of British Columbia, Canada, were estimated using data from a population-based survey in three health service delivery areas, namely Vancouver, East Kootenay and Northern Interior. The number of cases of disease, consequent expenditure of resources and associated economic costs were modeled as probability distributions in a stochastic model. Using 2004 prices, the estimated mean annual cost per capita of gastrointestinal infection was CAN$128.

Syndromic Surveillance of Norovirus using Over-the-counter Sales of Medications Related to Gastrointestinal Illness.

Objective: To assess whether over-the-counter (OTC) sales of gastrointestinal illness (GI)-related medications are associated with temporal trends of reportable community viral, bacterial and parasitic infections.

Methods: The temporal patterns in weekly and seasonal sales of nonprescription products related to GI were compared with those of reportable viral, bacterial and parasitic infections in a Canadian province.

Results: Temporal patterns of OTC product sales and Norovirus activity were similar, both having highest activity in the winter months.

Estimated Numbers of Community Cases of Illness Due to Salmonella, Campylobacter and Verotoxigenic Escherichia Coli: Pathogen-specific Community Rates.

Objective: To estimate the annual number of cases of illness due to verotoxigenic Escherichia coli (VTEC), Salmonella and Campylobacter in the Canadian population, using data from the National Notifiable Disease registry (NND), estimates of under-reporting derived from several National Studies on Acute Gastrointestinal Illness, and the literature.

Methods: For each of the three pathogens (VTEC, Salmonella and Campylobacter), data were used to estimate the percentage of cases reported at each step in the surveillance system. The number of reported cases in the NND for each pathogen was then divided by these percentages.

West Nile virus surveillance and diagnostics: A Canadian perspective.

A surveillance program has been in place since 2000 to detect the presence of West Nile virus (WNV) in Canada. Serological assays are most appropriate when monitoring for human disease and undertaking case investigations. Genomic amplification procedures are more commonly used for testing animal and mosquito specimens collected as part of ongoing surveillance efforts.

Physician diagnostic and reporting practices for gastrointestinal illnesses in three health regions of British Columbia.

Objectives: To estimate seasonal proportions of patient visits due to acute gastrointestinal illness (GI), assess factors influencing physicians' stool sample requests, their understanding of laboratory testing protocols and adherence to provincial stool request guidelines in three British Columbia (BC) health regions.

Methods: During a one-year period, eligible physicians were mailed four self-administered questionnaires used to estimate proportions of patients diagnosed with GI, related stool sample requests in the preceding month, and to assess factors prompting stool sample requests.

Results: The response rate overall for the initial comprehensive questionnaire was 18.

A common, symptom-based case definition for gastroenteritis.

National studies determining the burden of gastroenteritis have defined gastroenteritis by its clinical picture, using symptoms to classify cases and non-cases. The use of different case definitions has complicated inter-country comparisons. We selected four case definitions from the literature, applied these to population data from Australia, Canada, Ireland, Malta and the United States, and evaluated how the epidemiology of illness varied.

Development of a geographic information-driven real-time surveillance system for disease surveillance.

To respond to emerging public health threats such as West Nile virus, an advanced geographic information systems (GIS) -driven Web-based real-time surveillance system was developed to serve the National West Nile virus dead bird surveillance programme in Canada. The development of this system uses real-time Web GIS technologies and services to enhance conventional real-time surveillance systems based on real-time GIS requirements. The system has three modules: QuickTrack, QuickMap and QuickManage.

Under-reporting of infectious gastrointestinal illness in British Columbia, Canada: who is counted in provincial communicable disease statistics?

Under-reporting of infectious gastrointestinal illness (IGI) in British Columbia, Canada was calculated using simulation modelling, accounting for the uncertainty and variability of input parameters. Factors affecting under-reporting were assessed during a cross-sectional randomized telephone survey. For every case of IGI reported to the province, a mean of 347 community cases occurred (5th and 95th percentile estimates ranged from 181 to 611 community cases, respectively).

Population distribution and burden of acute gastrointestinal illness in British Columbia, Canada.

Background: In developed countries, gastrointestinal illness (GI) is typically mild and self-limiting, however, it has considerable economic impact due to high morbidity.

Methods: The magnitude and distribution of acute GI in British Columbia (BC), Canada was evaluated via a cross-sectional telephone survey of 4,612 randomly selected residents, conducted from June 2002 to June 2003. Respondents were asked if they had experienced vomiting or diarrhoea in the 28 days prior to the interview.

A GIS-driven integrated real-time surveillance pilot system for national West Nile virus dead bird surveillance in Canada.

Background: An extensive West Nile virus surveillance program of dead birds, mosquitoes, horses, and human infection has been launched as a result of West Nile virus first being reported in Canada in 2001. Some desktop and web GIS have been applied to West Nile virus dead bird surveillance. There have been urgent needs for a comprehensive GIS services and real-time surveillance.

Burden and cost of gastroenteritis in a Canadian community.

This study estimated the health burden and costs associated with gastroenteritis in the City of Hamilton (Ontario, Canada). The number of cases, number of different resource units used, and cost per resource unit were represented by probability distributions and point estimates. These were subsequently integrated in a stochastic model to estimate the overall burden and cost in the population and to depict the uncertainty of the estimates.

Estimating the burden of acute gastroenteritis, foodborne disease, and pathogens commonly transmitted by food: an international review.

The burden of foodborne disease is not well defined in many countries or regions or on a global level. The World Health Organization (WHO), in conjunction with other national public health agencies, is coordinating a number of international activities designed to assist countries in the strengthening of disease surveillance and to determine the burden of acute gastroenteritis. These data can then be used to estimate the following situations: (1) the burden associated with acute gastroenteritis of foodborne origin, (2) the burden caused by specific pathogens commonly transmitted by food, and (3) the burden caused by specific foods or food groups.

Estimating the under-reporting rate for infectious gastrointestinal illness in Ontario.

Background: In Ontario, infectious gastrointestinal illness (IGI) reporting can be represented by a linear model of several sequential steps required for a case to be captured in the provincial reportable disease surveillance system. Since reportable enteric data are known to represent only a small fraction of the total IGI in the community, the objective of this study was to estimate the under-reporting rate for IGI in Ontario.

Methods: A distribution of plausible values for the under-reporting rate was estimated by specifying input distributions for the proportions reported at each step in the reporting chain, and multiplying these distributions together using simulation methods.

Prospective surveillance of Canadian children with the haemolytic uraemic syndrome.

We determined prospectively the incidence of childhood diarrhoea associated haemolytic uraemic syndrome (D+ HUS) or HUS due to Streptococcus pneumoniae (SP+ HUS) in Canada through the Canadian Paediatric Surveillance Program (CPSP) network. From April 2000, to March 2002, 82% (1,886/2,300) of all Canadian paediatricians reported possible new cases of D+ HUS or SP+ HUS. Diagnosis was validated with a second questionnaire.

Syndromic surveillance of gastrointestinal illness using pharmacy over-the-counter sales. A retrospective study of waterborne outbreaks in Saskatchewan and Ontario.

Objective: To ascertain if monitoring over-the-counter (OTC) drug sales could provide a timely syndromic surveillance method of detecting outbreaks of gastrointestinal illness.

Method: This study evaluated the potential of a syndromic surveillance system by comparing retrospective pharmacy OTC sales of anti-nauseants and anti-diarrheals to emergency room visits and case numbers from two Canadian outbreaks related to water contamination by Cryptosporidium, and E.coli O157:H7 and Campylobacter.

From stool to statistics: reporting of acute gastrointestinal illnesses in Canada.

Background: Limitations associated with the under-reporting of enteric illnesses have long been recognized but the extent and variation of this under-reporting in Canada has not been examined. Given the public health value of surveillance data, a closer examination of under-reporting of enteric illnesses in Canada was warranted.

Methods: Paper-based surveys were administered (a) to all laboratories in Canada licensed to process stool specimens and (b) to all local public health authorities in two provinces.

Magnitude and distribution of acute, self-reported gastrointestinal illness in a Canadian community.

To estimate the magnitude and distribution of self-reported, acute gastrointestinal illness in a Canadian-based population, we conducted a retrospective, cross-sectional telephone survey of approximately 3500 randomly selected residents of the city of Hamilton (Ontario, Canada) from February 2001 to February 2002. The observed monthly prevalence was 10% (95 % CI 9.94-10.