Norovirus outbreak among primary schoolchildren who had played in a recreational water fountain

Background. A gastroenteritis outbreak was associated with playing in a norovirus-contaminated recreational fountain. Objective and study design. A retrospective cohort study was performed to estimate the magnitude of the outbreak and identify its source. Epidemiological investigation included standardized questionnaires about sex, age, school, class, risk exposures, and illness characteristics. Stool samples and environmental water samples were analyzed for the presence of bacteria, viruses, and parasites. Results. Questionnaires were returned for 191 schoolchildren (response rate, 83%) with a mean age of 9.2 years, of whom 47% were ill (diarrhea and/or vomiting). Children were more likely to have been ill if they had played in the recreational fountain (relative risk, 10.4). Norovirus (Birmingham) was detected in 22 (88%) stool specimens from ill children and in 6 (38%) specimens from healthy children. The water sample from the fountain contained a norovirus strain that was identical to the RNA sequence found in stools. Conclusions. Recreational water may be the source of gastroenteritis outbreaks. Adequate water treatment can prevent these types of outbreak.