RESUMO
An outbreak of gastroenteritis occurred in a school affecting more than 30% of its 535 students. An epidemiological survey questionnaire was given to all students as well as staff and maintenance personnel. Stool cultures and electronic microscopy were used to detect the presence of a Norwalk-like virus. Several analyses of water samples were also done. This outbreak occurred simultaneously in the two wings of the school (East and South). Those who used the East wing were most affected by the disease (RR = 1.45, CI 95%: 1,14-1,85). There was no indication of food or water supply contamination. A Norwalk-like virus was identified in the stool sample of one child. This along with the clinical characteristics strongly suggested that the pathogen was indeed a Norwalk-like virus. The analysis suggests transmission via contaminated surfaces but also via airborne transport of the infectious agent.
