Over a 14-year period (1984–97) the presence of rotavirus in stool samples from children under 15 years with acute gastroenteritis was studied by enzymoimmunoanalysis. Serotyping (G1–G4) was performed using monoclonal antibodies. A total of 17348 children under 15 were investigated. Rotavirus was detected in 3637 (21·0%) specimens, 74·6% of which were from children younger than 2 years old. G1 and G4 were the most frequent serotypes. In 1991–7, the minimum incidence of rotavirus gastroenteritis in children under 4 years of age was 21·7 cases/1000 children/year. By the age of 5 years, at least 1 out of 11·3 children and probably 1 out of every 5–6 children in this area had experienced an episode of rotavirus gastroenteritis that required medical care. In the 1984–90 period a clear seasonality was not observed but in the second period of the study (1991–7), seasonality was marked, with peak activity in winter
