A common, symptom-based case definition for gastroenteritis

ArticleinEpidemiology and Infection 136(7):886-94 · July 2008with54 Reads
Impact Factor: 2.54 · DOI: 10.1017/S0950268807009375 · Source: PubMed
Abstract

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.

    • "" Foodborne " indicates the mode of transmission, so definitions of FBD might vary depending on the targets of surveillance programs/projects. Two common definitions used in surveillance programs are the World Health Organization's (WHO) definition, " a disease of an infectious or toxic nature caused by or thought to be caused by the consumption of food or water, " (Schmidt and Gervelmeyer, 2003) and a symptom-based case definition for gastroenteritis, " a case of gastroenteritis is an individual with ≥ 3 loose stools, or any vomiting, in 24 h, " (Majowicz et al., 2008) although FBD may include other diseases than gastroenteritis (Flint et al., 2005). FBD outbreaks are defined as " two or more people who got gastrointestinal disorder after eating the same meal " (Lynch, Painter, Woodruff, and Braden, 2006; Olsen, MacKinnon, Goulding, Bean, and Slutsker, 2000; WHO, 2008). "
    [Show abstract] [Hide abstract] ABSTRACT: Foodborne diseases (FBD), with their varied clinical characteristics and causes, are a global public health concern. The World Health Organization (WHO) estimates that one billion people in developing countries and one-third of the population in developed countries are affected by FBD annually, resulting in significant economic losses. In Vietnam, approximately 200 foodborne outbreaks, 6,000 cases, and 50 deaths are reported annually. The majority of detected foodborne outbreaks have been linked to large canteens, while almost all fatal cases were associated with family meals. Public health statutory surveillance systems rely on outbreak investigation reports, and most outbreaks are only detected when severe cases are admitted to health facilities or when deaths occur. It is therefore clear that these figures are an underestimate, which implicates FBD as a significant public health and economic burden in Vietnam. In developing countries, public health systems face many challenges in ensuring food safety, including shortages of human resources, laboratory capacities, and financial resources. These shortcomings result in poor surveillance and response systems, which are not able to accurately estimate the burden of FBD, trends, contributing factors, and source attribution. Principles of food safety and best practices of food production are critical for comprehensive FBD prevention and control. However, capacity to monitor the complete food production chain is limited and outside the jurisdiction of public health. Therefore, studies in this dissertation focus on improving surveillance and response systems for food safety. The five studies (I to V) in this dissertation describe and evaluate the public health surveillance systems and responses to various foodborne outbreaks in Southern Vietnam from 2009 to 2013. Studies I to IV aim to identify the vehicles, sources, causative agents, and risk factors associated with the outbreak. These studies use various analytic methods to identify gaps and shortcomings in the surveillance and investigation of foodborne outbreaks. Study V then evaluates food-handlers’ food safety knowledge, attitudes, and practices at large canteens. The main findings of these studies help to identify feasible approaches to build capacity and improve public health practices in resource-poor settings. We identified likely outbreak vehicles and sources in four outbreak investigations, although we were unable to identify causative agents in Studies I and III. We identified risk factors contributing to these outbreaks, particularly the inadequate personal hygiene and food hygiene practices of food-handlers. Additionally, findings of outbreak investigations showed that only severe cases sought care at hospitals, clinicians alerted public health officials to suspected outbreaks, and these notifications were usually delayed. The notifiable disease system, operated by Southern Vietnam Preventive Medicine Centers, failed to detect clusters of cases or suspected foodborne outbreaks; it was also rare that surveillance data were analyzed and disseminated to Vietnam Food Safety Agencies (FSAs). Foodborne notification/complaint systems were not set up to receive FBD complaints from the public. Currently, only outbreak investigation reports are used to track food safety, but these reports usually contain only limited information and state few contributing factors and recommendations. Almost all public health/preventive medicine personnel in Southern Vietnam were trained to conduct outbreak investigations, but standard epidemiologic methods were not appropriately applied. For example, no standard case definitions and questionnaires were developed for conducting outbreak investigations. Most case information that food safety authorities reported was transcribed from hospital records. Investigators did not request or obtain any specimens from patients; conclusions regarding the causes of outbreaks were mainly based on results of laboratory tests of food samples. Food-preparation site investigations yielded inadequate information. No flow charts of food operations were drawn and no interviews with food-handlers were conducted, and stool samples of food-handlers and environmental samples were not taken as required. Although most FSAs had limited capacity to perform foodborne outbreak investigations, they rarely requested technical support from the central level. Most microorganism and physico-chemical testing in water and foods were conducted in laboratories at the central level. In Study V, we conducted a cross-sectional survey on food safety knowledge, attitudes, and practices (KAP) and on the training needs of food-handlers in large canteens. Of the 909 food-handlers participating in the study, knowledge, attitudes, and practices were considered adequate for 26%, 36%, and 26%, respectively. After controlling for potential confounders in logistic regression models, the number of food-handlers reporting adequate KAP in schools was about twice as high as the number of such food-handlers in factories. Food-handlers’ suggestions for training needs included appropriate location of the training venue at the workplace, involvement of managers, fewer trainees per course, more practical exercises, and longer course duration. In these studies, we found that public health surveillance systems for food safety are mainly based on foodborne outbreak investigations, response capacities to foodborne outbreaks are limited, and food-handlers’ KAP are poor. We therefore recommend the following: i) For public health surveillance and response in resource-poor settings, food safety authorities and policy-makers should consider including syndromic surveillance in food safety systems, based on existing notifiable disease reporting for infectious diseases. Notification/complaint systems should be available to receive calls from the public. ii) The Vietnam Field Epidemiology Training Program of the Ministry of Health, in collaboration with the Ministry of Agriculture and Rural Development, should develop a strategy and plan to train outbreak response teams at all administrative levels, in order to reach the target of making at least one trained field epidemiologist available per 200,000 people. iii) Efforts to educate food-handlers, together with supportive supervision conducted by managers, have great potential to improve food-handlers’ KAP, especially among those working in factories. iv) We recommend that further studies investigate contributing factors in food preparation and foodborne outbreaks, the burden of foodborne diseases, and source attribution.
    Full-text · Thesis · Jan 2016
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    • "An individual was classified as having diarrhea if the primary respondent reported (for himself or another member of the household) any occurrence of watery and/or soft diarrhea in the seven days preceding the survey while those classified as having vomiting reported any vomiting in the seven days preceding the survey. In addition, we adopted a case definition of acute gastroenteritis (AGI) recommended by Majowicz et al. [21] with some modifications due to limited clinical details. In our study we define a case of AGI as an individual with three or more loose stools or any vomiting in 24 h, but excluding those with irritable bowel syndrome, Crohn's disease, ulcerative colitis, celiac disease, or another condition with symptoms of diarrhea or vomiting such as pregnancy. "
    [Show abstract] [Hide abstract] ABSTRACT: Background: Community water supplies in underserved areas of the United States may be associated with increased microbiological contamination and risk of gastrointestinal disease. Microbial and health risks affecting such systems have not been systematically characterized outside outbreak investigations. The objective of the study was to evaluate associations between self-reported gastrointestinal illnesses (GII) and household-level water supply characteristics. Methods: We conducted a cross-sectional study of water quality, water supply characteristics, and GII in 906 households served by 14 small and medium-sized community water supplies in Alabama's underserved Black Belt region. Results: We identified associations between respondent-reported water supply interruption and any symptoms of GII (adjusted odds ratio (aOR): 3.01, 95% confidence interval (CI) = 1.65-5.49), as well as low water pressure and any symptoms of GII (aOR: 4.51, 95% CI = 2.55-7.97). We also identified associations between measured water quality such as lack of total chlorine and any symptoms of GII (aOR: 5.73, 95% CI = 1.09-30.1), and detection of E. coli in water samples and increased reports of vomiting (aOR: 5.01, 95% CI = 1.62-15.52) or diarrhea (aOR: 7.75, 95% CI = 2.06-29.15). Conclusions: Increased self-reported GII was associated with key water system characteristics as measured at the point of sampling in a cross-sectional study of small and medium water systems in rural Alabama in 2012 suggesting that these water supplies can contribute to endemic gastro-intestinal disease risks. Future studies should focus on further characterizing and managing microbial risks in systems facing similar challenges.
    Full-text · Article · Jan 2016 · PLoS ONE
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    • "In five recently completed telephone surveys conducted across European Union Member States, self-reported illness rates ranged from 1.4 cases per person per year in Denmark to 0.33 cases per person per year in France56789 . However, comparing international rates is hampered by disparities in case definitions , study designs, periods of recall of symptoms and the characteristics of the populations studied [10,11]. Most people with IID do not seek medical attention [2,4], and even when they do their illness is often not investigated or reported [12] , so it is difficult to determine accurately the population incidence of disease based on national surveillance or other routinely collected data. "
    [Show abstract] [Hide abstract] ABSTRACT: To estimate the burden of intestinal infectious disease (IID) in the UK and determine whether disease burden estimations using a retrospective study design differ from those using a prospective study design. A retrospective telephone survey undertaken in each of the four countries comprising the United Kingdom. Participants were randomly asked about illness either in the past 7 or 28 days. 14,813 individuals for all of whom we had a legible recording of their agreement to participate. Self-reported IID, defined as loose stools or clinically significant vomiting lasting less than two weeks, in the absence of a known non-infectious cause. The rate of self-reported IID varied substantially depending on whether asked for illness in the previous 7 or 28 days. After standardising for age and sex, and adjusting for the number of interviews completed each month and the relative size of each UK country, the estimated rate of IID in the 7-day recall group was 1,530 cases per 1,000 person-years (95% CI: 1135-2113), while in the 28-day recall group it was 533 cases per 1,000 person-years (95% CI: 377-778). There was no significant variation in rates between the four countries. Rates in this study were also higher than in a related prospective study undertaken at the same time. The estimated burden of disease from IID varied dramatically depending on study design. Retrospective studies of IID give higher estimates of disease burden than prospective studies. Of retrospective studies longer recall periods give lower estimated rates than studies with short recall periods. Caution needs to be exercised when comparing studies of self-reported IID as small changes in study design or case definition can markedly affect estimated rates.
    Full-text · Article · Jan 2016 · PLoS ONE
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