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. Questions pertained to recent symptoms as well as socio-demographic factors, use of the health care system and missed work or school due to illness. RESULTS: In summary of published results, there are an estimated 1.3 episodes of AGI per person-year and an estimated 10-47, 13-37 and 23-49 cases in the community for every case of verotoxigenic Escherichia coli, Salmonella and Campylobacter, respectively, captured within the national surveillance system. AGI represents an annual per capita cost of $115 CAD. DISCUSSION: The work of NSAGI highlights the significant burden and impact of AGI in the Canadian population. These results will also be incorporated into the current work at the World Health Organization (WHO) to estimate the global burden of food related illnesses.

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$128.61 (207.96 euros), with a mean annual cost per case of CAN$1,342.57 (2,170.99 euros). The mean estimate of the overall economic burden to British Columbia was CAN$514.2 million (831.5 million euros) (95% CFI CAN$161.0 million to CAN$5.8 billion; 260.3 million euros to 9.38 billion euros). The major element of this cost was the loss of productivity associated with time away from paid employment by both the sick and their caregivers. Sensitivity analysis suggested that the uncertainty associated with the base model assumptions did not significantly affect the estimates. The results are comparable to those obtained in an earlier study using a similar analytical framework and data from the city of Hamilton, Ontario, Canada.

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. Based on the results, we developed a standard case definition. The choice of case definition impacted on the observed incidence of gastroenteritis, with a 1.5-2.1 times difference between definitions in a given country. The proportion of cases with bloody diarrhoea, fever, and the proportion who sought medical care and submitted a stool sample also varied. The mean age of cases varied by <5 years under the four definitions. To ensure comparability of results between studies, we recommend a standard symptom-based case definition, and minimum set of results to be reported.

The study of infectious intestinal disease in England: socio-economic impact.

To assess the socio-economic impact of infectious intestinal disease (IID) on the health care sector, cases and their families, cases of IID ascertained from a population cohort component and those presenting to general practices were sent a socio-economic questionnaire 3 weeks after the acute episode. The impact of the illness was measured and the resources used were identified and costed. The duration, severity and costs of illness linked to viruses were less than those linked to bacteria. The average cost per case of IID presenting to the GP was Pound Sterling253 and the costs of those not seeing a GP were Pound Sterling34. The average cost per case was Pound Sterling606 for a case with salmonella, Pound Sterling315 for campylobacter, Pound Sterling164 for rotavirus and Pound Sterling176 for SRSV. The estimated cost of IID in England was Pound Sterling743m expressed in 1994/5 prices. The costs of IID are considerable and the duration of the illness was found to be longer than previous reports have suggested.

Enteric and foodborne disease in children: A review of the influence of food- and environment-related risk factors.

Canadian statistics show that children from birth to four years of age are more likely to be reported with an infection from Campylobacter, Giardia, Salmonella and Shigella species, and verotoxigenic Escherichia coli than any other age group. A review of the Canadian and international literature, and an analysis of case and outbreak data suggest that the risk factors for infection in young children (ages birth to four years) are different from the risk factors for older children and adults. In children from birth to four years of age, infant formula, fast foods, snacks and candies have caused major outbreaks of enteric and foodborne diseases; however, the contamination of a child's environment or the presence of ill individuals in a household may be highly significant to disease expression. Contact with animals (including family pets) and contaminated surfaces, together with experimental touching and testing behaviours, are important routes of infection for infants and preschool children. Risk factors for enteric infections in children appear to be related, occasionally, to specific foods that are particularly attractive to all children (all age groups from infants up to and including elementary school-aged childen), to an infected person or pet in the same household, or to the contamination of a child's environment. Nonfood-related risk factors may be of particular significance in infection in infants and very young children. Contact with animals, particularly exotic pets and farm animals, or their environments should be considered to be a potential source of infection in children in situations in which there is an absence of other risk factors. The evidence presented in the current paper emphasizes the importance of personal and home hygiene practices in limiting children's exposure to enteric pathogens. Strict hand washing practices and restrictions on touching birds, reptiles and other animals at petting zoos or in nursery and primary school facilities are recommended to avoid widespread infection. Public health authorities should consider the development of guidelines on the provision of hand washing facilities and instruction notices in settings where the public may come into contact with farm or other animals in jurisdictions where such guidelines do not already exist.

A study of infectious intestinal disease in England: plan and methods of data collection.

The Committee on the Microbiological Safety of Food, set up in 1989 by the Department of Health in response to national epidemics of foodborne infection, considered the available evidence and commissioned a study of infectious intestinal disease (IID) in England. Seventy practices (with 489,500) patients overall) recruited from the Medical Research Council's General Practice Research Framework between August 1993 and January 1995 collected data for one year. The practice populations were representative of practices in England by area and urban/rural location, but with fewer small and affluent practices. There were five main components. i) A population cohort of 9776 (40% of those eligible) were enrolled to estimate the incidence and aetiology of IID in the community, and a large proportion were followed up. A median of 10% of patients on practice age-sex registers had moved away or died. ii) A nested case control component based on cases ascertained in the cohort was used to identify risk factors for IID in the community. iii) In a case control component used to identify risk factors and to estimate the incidence and aetiology of IID presenting in 34 general practices 70% of the 4026 cases returned risk factor questionnaires, 75% submitted stools, and matched controls were found for 75% of cases. iv) An enumeration component was used to estimate the incidence of IID presenting to general practitioners (GPs) in 36 practices and the proportion of specimens sent routinely for microbiological examination. v) In a socioeconomic costs component used to estimate the burden of illness of IID in the community and presenting to GPs 63% of those who returned a risk factor questionnaire also returned a socioeconomic questionnaire and were representative by age, sex, and social class. Despite variable enrolment and compliance the study sample had sufficient power for the multivariable analysis. The characteristics associated with low enrollment and compliance must be considered in the interpretation of the main study results.

The socio-economic impact of human Salmonella enteritidis infection.

Recent government and public concern about the recorded increase in human salmonellosis in the UK and abroad has stimulated investigations of both the causes and consequences of these infections. This paper discusses the framework for economic analysis of food-borne disease and problems associated with the estimation of costs. A brief review of the literature in this area is given and the results of a national study of the costs of human salmonellosis in England and Wales are presented and used to estimate the likely costs of S. enteritidis infection.

Foodborne disease surveillance in England and Wales: 1989-1991.

This review summarises reports of food poisoning, salmonellosis, campylobacteriosis and other acute foodborne illness to the PHLS Communicable Disease Surveillance Centre, and notifications of food poisoning collated by the Office of Population Censuses and Surveys, in the period 1989-1991. During this period there were continuing rises in notifications of food poisoning and reports of salmonellosis and campylobacteriosis. There was considerable success in the control of foodborne listeriosis. Newly emerging pathogens, such as Vero cytotoxin producing Escherichia coli, became more important. There was unprecedented scrutiny of the salmonella data by experts and politicians, reflecting continuing concern over the role of eggs as well as poultry meat in the increase of Salmonella enteritidis phage type 4 infection. This concern, along with advances in information technology, has led to developments in the collection and dissemination of information which continue to be implemented.

Brucellosis: imported and laboratory-acquired cases, and an overview of treatment trials.

Following the successful eradication of Brucella abortus infection in cattle, human brucellosis in England and Wales has become an uncommon imported disease. Culture of the organism presents a major laboratory hazard, and difficulties in identification may occur using a biochemical test-strip method. An overview of recent treatment trials of brucellosis indicates that regimens combining streptomycin and doxycycline are associated with a higher success rate (judged by the frequency of treatment failure and relapse following therapy) than combinations of rifampicin and doxycycline.

The social and economic impact of salmonellosis. A report of a national survey in England and Wales of laboratory-confirmed Salmonella infections.

This study presents the findings of a national survey of 1482 cases of salmonellosis reported to Environmental Health Departments in England and Wales between August 1988 and March 1989. A questionnaire survey of ill individuals and the environmental health officers who investigated them sought information about costs which were imposed upon public health authorities, the health sector, individuals and their families and the costs to the wider economy in terms of lost production. Costs of 996,339 pounds were identified. Over half (507,555 pounds) resulted from lost production due to sickness absence and more than a third (392,822 pounds) were costs to the public sector which resulted from health care and local authority investigation of cases. The remaining costs (95,962 pounds), although the smallest proportion of the total, indicated that salmonellosis can have a significant impact on affected individuals and their families.

Food poisoning outbreaks associated with manufactured foods in England and Wales: 1980-1989.

In the ten-year period, 1980-89, 294 reported outbreaks of food poisoning were associated with eating pre-cooked sliced meats, meat products and other manufactured foods in England and Wales, including 65 outbreaks in which the product was imported. Salmonellas were the most commonly reported agent, causing 132 (45%) of the outbreaks; other bacteria caused a further 51 (17%) outbreaks. The remainder were due to viruses (five outbreaks), scombrotoxin (60 outbreaks), or were of unknown cause (46 outbreaks). The number of outbreaks associated with manufactured foods accounted for only a small proportion (less than 5%) of food poisoning outbreaks reported to CDSC during this period and needs to be set against the huge amounts of manufactured foods consumed. However, because of the quantities made and the widespread distribution of particular products, such outbreaks may affect many individuals who are geographically widespread.

The tangible cost implications of a hospital outbreak of multiply-resistant Salmonella.

A hospital outbreak of multiply-resistant Salmonella heidelberg infection, which affected 17 patients and 2 staff, is described. The tangible cost of the outbreak was estimated at 21 pounds 151, 17 pounds 989 (85.1%) of which was borne by the hospital. The cost to the Microbiology Department was 3596 pounds (17.0% of the total). A detailed analysis of the costs and implications for staffing disruption is given and a comparison is made with the costs of preventive activities. Ways of containing expenses in the event of an outbreak and the economic implications for clinical budgeting and privatization of the laboratory service are considered.

Economic impact of a nationwide outbreak of salmonellosis: cost-benefit of early intervention.

The recognition and investigation of an outbreak of food poisoning in 1982 due to chocolate contaminated with Salmonella napoli enabled the food that carried the salmonella to be identified and four fifths of the implicated consignment of chocolate to be withdrawn. The economic benefits of prompt intervention in the outbreak have been assessed. The cost of the outbreak was over 0.5 pounds m. It is estimated that five deaths were prevented by the intervention and that 185 admissions to hospital and 29,000 cases of S napoli enteritis were avoided. This successful investigation yielded a 3.5-fold rate of return to the public sector and a 23.3-fold return to society on an investment in public health surveillance. A methodology is described that can be used to estimate the benefits of early intervention in outbreaks of foodborne illness and topics for further research are suggested. It is concluded that public health authorities and industry have much to gain by collaborating in the research into the design of cost effective programmes to prevent foodborne infections.