Incidence of self-reported acute gastrointestinal infections in the community in Poland: a population-based study.

A retrospective cross-sectional survey of self-reported acute gastrointestinal infection (AGI) incidence in the community was performed in Poland, from December 2008 to November 2009. The aim of the study was to estimate the magnitude and distribution of self-reported AGI, in order to calibrate the routine AGI surveillance system in Poland. The study population were randomly selected residents of all Polish regions, having a fixed telephone line. An equal number of telephone interviews were collected each month, requesting the interviewee to identify gastrointestinal symptoms that had occurred in the previous 4 weeks. The international AGI case definition was used. In total 3583 complete interviews were obtained. The compliance ratio was 26%. Of 3583 respondents, 240 (6.7%) individuals fulfilled the AGI case definition. The annualized incidence of acute gastroenteritis was 0.9/person-year (95% confidence interval 0.8-1.0). Comparison of the obtained annual AGI estimate (33.3 million infections) with the number of cases reported to national surveillance during the corresponding period (73 512), yielded an underreporting factor of 453 cases occurring in the community for each reported case. Of the 240 AGI cases, 30.4% consulted a general practitioner, and 4.6% were admitted to hospital. Samples for microbiological confirmation were collected from four (1.6%) cases. This first population-based study in eastern Europe has confirmed that AGI places a high burden on Polish society, which is underestimated by national surveillance data. Efforts are necessary to improve AGI reporting and diagnostic practices in order to increase the effectiveness of the Polish surveillance system in detecting threats related to new AGI pathogens, new routes of transmission or the potential for international spread.