[Norovirus outbreak in Majorca (Spain) associated with oyster consumption]. / Brote de norovirus en Mallorca asociado al consumo de ostras.

We describe investigation into an outbreak of norovirus gastroenteritis associated with oyster consumption. A survey was conducted in 346 exposed persons, 266 of whom were cases. Only 14 feces samples from patients were sent to the National Microbiology Laboratory. Oysters collected at the production site were sent to the National Food Center. The oysters met the microbiological quality standard required before sale, which did not include virus investigation. Epidemiological analysis showed an association between gastroenteritis and consumption of oysters (OR = 60.4; 95% CI: 26.2-139.3) and razor shells (OR = 3.13; 95% CI: 1.4-6.9). Microbiological analysis confirmed norovirus in affected individuals but not in the oysters that had been tested after a longer purification period than those consumed. Food with a special risk of norovirus transmission should be strictly monitored. Investigators should dispose of the necessary laboratory resources to study food-borne norovirus outbreaks.

[Incidence and risk factors for acute gastroenteritis among pilgrims following the French way to Santiago de Compostela (Spain) in 2008]. / Incidencia y factores de riesgo de gastroenteritis en los peregrinos del Camino de Santiago durante el verano de 2008 en el camino francés.

OBJECTIVES: To determine the incidence of acute gastroenteritis in pilgrims on St. James' Way, as well as associated risk factors and microbiological characteristics. METHODS: Two studies were designed simultaneously: a cross-sectional study through self-completed questionnaires among pilgrims reaching Santiago, and a case-control study of pilgrims traveling along the Way. Multivariate analysis was performed using logistic regression. RESULTS: In the cross-sectional study, the incidence rate was 23.5 episodes of acute gastroenteritis/10³ pilgrims-day (95% CI: 18.9-2.4/10³. In the case-control study, the major risk factors were age <20 years (OR=4.72; 95% CI: 2.16-10.28), traveling in groups (three or more) (OR=1.49; 95% CI: 0.98-2.28), and drinking unbottled water (OR=2.09; 95% CI: 0.91-4.82). The most frequent etiologic agent was norovirus (56%). CONCLUSIONS: Age less than 20 years, traveling in groups and drinking unbottled water were important risk factors for acute gastroenteritis.