A common, symptom-based case definition for gastroenteritis

Foodborne, Waterborne, and Zoonotic Infections Division, Public Health Agency of Canada, Guelph and Ottawa, ON, Canada.
Epidemiology and Infection (Impact Factor: 2.54). 07/2008; 136(7):886-94. DOI: 10.1017/S0950268807009375
Source: PubMed


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.

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Available from: Shannon Majowicz, May 05, 2014
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    • "One reason for the change in illness definition was to allow consideration of viral illness (such as norovirus) which may not produce high fever in combination with GI symptoms. This case definition is more similar to that suggested by a group of international experts who proposed that a uniform international definition should include vomiting or diarrhea constituting greater than or equal to three soft stools in a 24 hour period without a requirement of fever [13], as well as by the World Health Organization [14]. The revised definition is also similar to definitions used in other epidemiology studies of GI illness in relation to waterborne exposures in North America [15-17]. "
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    ABSTRACT: Background The United States Environmental Protection Agency (USEPA) and its predecessors have conducted three distinct series of epidemiological studies beginning in 1948 on the relationship between bathing water quality and swimmers’ illnesses. Keeping pace with advances in microbial technologies, these studies differed in their respective microbial indicators of water quality. Another difference, however, has been their specific health endpoints. The latest round of studies, the National Epidemiological Assessment of Recreational (NEEAR) Water studies initiated in 2002, used a case definition, termed “NEEAR GI illness” (NGI), for gastrointestinal illness corresponding closely to classifications employed by contemporary researchers, and to that proposed by the World Health Organization. NGI differed from the previous definition of “highly credible gastrointestinal illness” (HCGI) upon which the USEPA’s 1986 bathing water criteria had been based, primarily by excluding fever as a prerequisite. Methods Incidence of NGI from the NEEAR studies was compared to that of HCGI from earlier studies. Markov chain Monte Carlo method was used to estimate the respective beta binomial probability densities for NGI and HCGI establish credible intervals for the risk ratio of NGI to HCGI. Results The ratio of NGI risk to that of HCGI is estimated to be 4.5 with a credible interval 3.2 to 7.7. Conclusions A risk level of 8 HCGI illnesses per 1000 swimmers, as in the 1986 freshwater criteria, would correspond to 36 NGI illnesses per 1000 swimmers. Given a microbial DNA-based (qPCR) water quality vs. risk relationship developed from the NEEAR studies, 36 NGI per 1000 corresponds to a geometric mean of 475 qPCR cell-equivalents per 100 ml.
    BMC Public Health 05/2013; 13(1):459. DOI:10.1186/1471-2458-13-459 · 2.26 Impact Factor
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    • "It is difficult to compare AGI rates between studies due to the use of different case definitions and study designs. Using the standard symptom-based case definition for AGI proposed by Majowicz et al. [9], we obtained similar results as compared with those using the chosen definition in our primary analysis. We thus reported the suggested minimum set of results in this article, in order to facilitate international comparisons. "
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    ABSTRACT: Background Acute gastrointestinal illness (AGI) is an important public-health problem worldwide. Previous national studies of the incidence of AGI in China were performed decades ago, and detailed information was not available. This study therefore sought to determine the magnitude, distribution, and burden of self-reported AGI in China. Methods Twelve-month, retrospective face-to-face surveys were conducted in 20 sentinel sites from six provinces between July 2010 and July 2011. Results In total, 39686 interviews were completed. The overall adjusted monthly prevalence of AGI was 4.2% (95% confidence interval, 4.0–4.4), corresponding to 0.56 episodes of AGI per person-year. Rates of AGI were highest in children aged < 5 years. Healthcare was sought by 56.1% of those reporting illness. Of the cases who visited a doctor, 32.7% submitted a stool sample. The use of antibiotics was reported by 49.7% of the cases who sought medical care and 54.0% took antidiarrhoeals. In the multivariable model, gender, age, education, household type, residence, season, province and travel were significant risk factors of being a case of AGI. Conclusions This first population-based study in China indicated that AGI represents a substantial burden of health. Further research into the specific pathogens is needed to better estimate the burden of AGI and foodborne disease in China.
    BMC Public Health 05/2013; 13(1):456. DOI:10.1186/1471-2458-13-456 · 2.26 Impact Factor
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    • "Another of the major challenges in international comparisons of IID incidence rates, regardless of the study design, is the variation in case definitions. Indeed the case definition can influence the observed incidence of gastroenteritis by as much as 1.5-2.1 times in a given country [19]. To overcome this, a standard, symptom-based definition has been developed that should allow international comparison in the future [19]. "
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    ABSTRACT: Infectious intestinal disease (IID), usually presenting as diarrhoea and vomiting, is frequently preventable. Though often mild and self-limiting, its commonness makes IID an important public health problem. In the mid 1990s around 1 in 5 people in England suffered from IID a year, costing around pound0.75 billion. No routine information source describes the UK's current community burden of IID. We present here the methods for a study to determine rates and aetiology of IID in the community, presenting to primary care and recorded in national surveillance statistics. We will also outline methods to determine whether or not incidence has declined since the mid-1990s. The Second Study of Infectious Intestinal Disease in the Community (IID2 Study) comprises several separate but related studies. We use two methods to describe IID burden in the community - a retrospective telephone survey of self-reported illness and a prospective, all-age, population-based cohort study with weekly follow-up over a calendar year. Results from the two methods will be compared. To determine IID burden presenting to primary care we perform a prospective study of people presenting to their General Practitioner with symptoms of IID, in which we intervene in clinical and laboratory practice, and an audit of routine clinical and laboratory practice in primary care. We determine aetiology of IID using molecular methods for a wide range of gastrointestinal pathogens, in addition to conventional diagnostic microbiological techniques, and characterise isolates further through reference typing. Finally, we combine all our results to calibrate national surveillance data. Researchers disagree about the best method(s) to ascertain disease burden. Our study will allow an evaluation of methods to determine the community burden of IID by comparing the different approaches to estimate IID incidence in its linked components.
    BMC Medical Research Methodology 05/2010; 10(1):39. DOI:10.1186/1471-2288-10-39 · 2.27 Impact Factor
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