[The burden of acute gastrointestinal illness in Hesse--a telephone survey].

Introduction: Mandatory notifications of laboratory diagnosed cases of acute gastroenteritis are essential for public health surveillance of food-borne diseases; however, reported cases represent a subset of infection in the community. We aimed to determine the magnitude and distribution of self-reported, acute gastrointestinal illness in Hesse, Germany, and to describe factors associated with seeking medical care.

Methods: We conducted a retrospective, cross-sectional telephone survey in 4 551 randomly selected households from September 2004 to August 2006. We used a standardised questionnaire to collect data on the interview partner and all children ≤ 15 years living in the household. The case definition was 3 or more loose stools or any vomiting in 24 h, during the 4 weeks preceding the interview, but excluding those with non-infectious causes. Frequency data were weighted to the Hessian population.

Results: Among the contacted households, 81% participated. 137 of the 2 100 children ≤ 15 years met the case definition, yielding an adjusted annual incidence rate of 0.86 (95% CI 0.72-1.03) episodes per person-year. 167 of the 4 551 study participants ≥ 16 years met the case definition, yielding an adjusted annual incidence rate of 0.46 (95% CI 0.37-0.51) episodes per person-year. This extrapolates to 807 000 (95% CI 672 000-962 000) cases of acute gastroenteritis in Hesse each year for children ≤ 15 years of age and 2 225 000 (95% CI 1 880 000-2 625 000) cases in individuals ≥ 16 years. On multivariate analysis, among individuals aged ≤ 15 years with an acute gastroenteritis, factors associated with seeking medical care included age, vomiting ≥ 3 times in 24 h, fever, and duration of illness. Among cases ≥ 16 years, duration of illness was associated with seeking medical care. Of those seeking medical care, 15% provided a stool sample.

Conclusion: Acute gastrointestinal illness appears to pose a significant burden in the Hessian population. Cases of acute gastrointestinal illness ascertained through laboratory-based public health surveillance likely differ systematically from unreported cases. Further research into the pathogen-specific burden is needed to better target intervention strategies.