En mayo de 1989 se produjo un brote de toxiinfección alimentaria (TIA) en el colegio público de Adzaneta, Castellón. Se realizó un estudio para describirlo, averiguar sus causas y adoptar las medidas de control adecuadas. Afectó a 16 niños y 2 profesores (tasa de ataque: 28,57 %). Se cumplieron los criterios clínicos y epidemiológicos para considerar al virus Norwalk como agente responsable. Probablemente su origen estuvo en un manipulador enfermo. En heces de éste y de un caso se visualizaron (ME) estructuras redondas de tamaño similar al virus Norwalk. En España el número de brotes de TIA sin agente causal conocido ha aumentado en los últimos años. Quizá este microorganismo sea responsable de una parte de estos brotes en los que, por diversos motivos, no se llega a identificar su agente causal.

In May 1989, a foodborne outbreak of acute gastroenteritis was Identified in a state school in Adzaneta, Castellón. A dtudy was undertaken to describe it, investigate its causes, and recommend adequate control measures. Sixteen children and 2 teachers were affected (attack rate: 28.57 %). Kaplan and cols clinical and epidemiological criteria for Norwalk-like virus as the responsable agent were present. The probable origin of the outbreak was a foodhandler who was already ill beforehand. The examination of stools of the foodhandler and a patient showed small round structures similar to the Norwalk virus. In Spain, the number of foodborne outbreaks without known causal agent has steadily increased in recent years. It may be that this microorganism is responsible for some of these outbreaks in which, for several reasons, the causal agent cannot be Identified.