Abstract
Little is known of the frequency of norovirus infections in sporadic gastroenteritis cases. In a 4-y study, we examined 1152 rota-, adeno- and astrovirus negative stool samples for human noroviruses; 187 (16.2%) proved to be positive. Stool samples were from paediatric patients with acute gastroenteritis. All isolates were verified as sporadic cases: there was no accumulation.