BACKGROUND: The great impact of rotavirus disease on morbidity and medical health care costs in industrialized countries together with the withdrawal of the live oral rotavirus vaccine have made a reassessment of rotavirus gastroenteritis necessary. Such a reassessment should provide sufficient data for developing alternative disease prevention strategies and for allocating resources efficiently. OBJECTIVES: To compare characteristics and management of community- and nosocomially acquired rotavirus disease in Austria, Germany and Switzerland. PATIENTS AND METHODS: In a prospective, population-based, trinational (Austria, Germany, Switzerland), multicenter (9 cities, 10 hospitals and 30 pediatric practices) study, a total of 174 552 children months and 78 516 hospital days were evaluated. Participants were all children 4 years of age and younger, who either presented at one of the pediatric practices with community-acquired gastroenteritis, or who had acquired gastroenteritis nosocomially. From December, 1997, to May, 1998, prospective antigen testing was done by enzyme-linked immunosorbent assay, and serotyping was done by reverse transcription polymerase chain reaction. Disease severity was scored by the Vesikari severity scale. RESULTS: Rotavirus was detected in 29.5, 27 and 37.5% of children with community-acquired gastroenteritis and in 57, 69 and 49% of children with nosocomial gastroenteritis in Austria, Germany and Switzerland, respectively. Severity of community-acquired rotavirus gastroenteritis was more pronounced in Austria (median severity score, 11) than in Germany (median score, 9) or Switzerland (median score, 10). However, only 2% of Austrian and Swiss children compared with 12% of German children presented to their pediatricians more than four times. Nosocomially acquired rotavirus gastroenteritis was mildest in Austria but occurred within the shortest median duration of hospitalization (4 days vs. 5 and 7 in Germany and Switzerland, respectively). In a multivariant analysis age, family size, day care, breast-feeding and nationality were not predictive factors for enhanced risk to contract rotavirus infection. Alimentation was changed frequently; diet was used between 23 and 83%; special formulas were used between 10 and 57%. CONCLUSION: The cumulative experience from three European countries suggest that rotavirus is an important cause of diarrhea in Central Europe, but significant local differences clearly demonstrate the need for obtaining national data as a reliable basis for control and prevention of the disease.