[Outbreak of food-borne Norovirus associated with the consumption of sandwiches]. / Toxiinfección alimentaria por Norovirus debida al consumo de bocadillos.

BACKGROUND AND OBJECTIVE: The aim of this study was to conduct an investigation into an outbreak of food-borne disease at a hotel, when epidemiological and microbiological results determined that the etiological agent was Norovirus and the source of infection was food handlers. PATIENTS AND METHOD: We detected an outbreak of gastroenteritis in a group of 59 students and teachers from a secondary school who were staying at a hotel in Espot, Lleida (Spain). A historic cohort study was conducted into the consumption of water and food and clinical symptoms were also analyzed. We studied the water supply and various food items. Faecal specimens from 14 patients and four food handlers were cultured and examined for Norovirus by PCR-RT. The influence of each foodstuff was assessed by relative risk (RR) at 95% confidence intervals. RESULTS: We interviewed 96.6% of the patients (57/59). The overall attack rate was 66.7% (38/57). The median period of incubation was 25.0 hours (maxim 59 and minimum 19 hours). Symptoms included abdominal pain 94.7% (36/38), vomiting 86.8% (33/38), nausea 76.3% (29/38), diarrhoea 52.6% (20/38) and fever 48.6% (17/35). Of the four different kinds of drinking water and 13 food items studied, the only significant factor was the consumption of sandwiches (RR = 2.3; CI 95%, 1.1-5.1). Cultures were negative for bacteria. PCR-RT tests were positive for Norovirus in 12 of 14 faecal samples. There were also positive results for the same virus in two of four faecal samples from food handlers, although neither of them presented clinical symptoms. CONCLUSIONS: This research highlights the fact that food-handlers should always be investigated in the case of outbreaks of food borne Norovirus. They must strictly follow hygiene rules, especially when they produce food that is to be eaten without any form of cooking.

Toxiinfección alimentaria por norovirus debida al consumo de bocadillos / Outbreak of food-borne norovirus associated with the consumption of sandwiches

FUNDAMENTO Y OBJETIVO: Se ha investigado un brote de toxiinfección alimentaria que afectó a los clientes de un hotel y en el que la epidemiología analítica y el análisis microbiológico permitieron determinar que el agente etiológico fue Norovirus y la fuente de infección, los manipuladores de alimentos. PACIENTES Y MÉTODO: El día 26 de junio de 2002 se detectó un brote de gastroenteritis que afectaba a un grupo de 59 alumnos y profesores de un colegio alojados en un hotel de Espot (Lleida).Se realizó un estudio de cohortes históricas sobre la exposición a aguas y alimentos y síntomas clínicos. Se estudiaron el sistema de suministro y distribución del agua de la red municipal y los menús consumidos. La investigación microbiológica consistió en el coprocultivo y la determinación de Norovirus en heces de 14 enfermos y de 4 manipuladores. La implicación de cada alimento se estudió mediante el riesgo relativo (RR) y el intervalo de confianza del 95%. RESULTADOS: Se entrevistó al 96,6% de los expuestos (57/59). La tasa de ataque global fue del 66,7% (38/57). La mediana del período de incubación fue de 25,0 h (máximo de 51 y mínimo de 19 h). La proporción de síntomas fue: dolor abdominal en el 94,7% (36/38), vómitos en el86,8% (33/38), náuseas en el 76,3% (29/38), diarrea en el 52,6% (20/38) y fiebre en el48,6% (17/35). De los 4 tipos de agua y de los 13 alimentos estudiados, el único que resultó implicado fue el consumo de bocadillos (riesgo relativo = 2,3; intervalo de confianza del 95%, 1,1-5,1).Los coprocultivos fueron negativos. En el análisis por reacción en cadena de la polimerasa, 12 de las 14 muestras de heces de enfermos resultaron positivas a Norovirus. También se obtuvo un resultado positivo al mismo virus en 2 de los 4 manipuladores. Ninguno de ellos había presentado síntomas clínicos. CONCLUSIONES: Los manipuladores deben ser investigados sistemáticamente en los brotes por Norovirus y además deben cumplir de forma estricta las recomendaciones higiénicas, especialmente en la preparación de alimentos de consumo en crudo

BACKGROUND AND OBJECTIVE: The aim of this study was to conduct an investigation into an outbreakof food-borne disease at a hotel, when epidemiological and microbiological results determined that the etiological agent was Norovirus and the source of infection was food handlers. PATIENTS AND METHOD: We detected an outbreak of gastroenteritis in a group of 59 students and teachers from a secondary school who were staying at a hotel in Espot, Lleida (Spain). Ahistoric cohort study was conducted into the consumption of water and food and clinical symptoms were also analyzed. We studied the water supply and various food items. Faecal specimens from 14 patients and four food handlers were cultured and examined for Norovirusby PCR-RT. The influence of each foodstuff was assessed by relative risk (RR) at 95% confidence intervals. RESULTS: We interviewed 96.6% of the patients (57/59). The overall attack rate was 66.7% (38/57). The median period of incubation was 25.0 hours (maxim 59 and minimum 19 hours). Symptoms included abdominal pain 94.7% (36/38), vomiting 86.8% (33/38), nausea 76.3%(29/38), diarrhoea 52.6% (20/38) and fever 48.6% (17/35). Of the four different kinds of drinking water and 13 food items studied, the only significant factor was the consumption of sandwiches (RR = 2.3; CI 95%, 1.1-5.1). Cultures were negative for bacteria. PCR-RT tests were positive for Norovirus in 12 of 14 faecalsamples. There were also positive results for the same virus in two of four faecal samples from food handlers, although neither of them presented clinical symptoms. CONCLUSIONS: This research highlights the fact that food-handlers should always be investigated in the case of outbreaks of food borne Norovirus. They must strictly follow hygiene rules, especially when they produce food that is to be eaten without any form of cooking