Gaceta Sanitaria (Feb 2008)
Brote de shigellosis con 146 casos relacionado con una feria Shigellosis outbreak with 146 cases related to a fair
Abstract
Fundamento: El 3 de septiembre de 2005, el Servicio de Salud Pública de Ciudad Real conoció la existencia de 20 casos de gastroenteritis en el municipio de Daimiel. Se inició una investigación, con los objetivos de determinar las causas y establecer medidas de control. La mayor parte de los afectados eran jóvenes que habían visitado la feria de la localidad. Métodos: Se llevó a cabo un estudio descriptivo y otro analítico de casos y controles. En el descriptivo se incluyeron todas las variables de interés disponibles en las historias clínicas de los pacientes. Se diseñó un estudio de casos y controles apareado por edad (más o menos 5 años), sexo y asistencia a la feria, que incluyó a 65 casos y a 65 controles. Se llevaron a cabo inspecciones de establecimientos y toma de muestras clínicas y de alimentos. Resultados: Se notificaron 196 casos, de los cuales 146 fueron confirmados. La curva epidémica sugiere una fuente común de corta duración. El estudio de casos y controles apareado muestra una asociación con el consumo de patatas con salsa en uno de los chiringuitos (odds ratio [OR] = 20,56; intervalo de confianza [IC] del 95%, 6,15-75,93; p Background: On September 3, 2005, the Ciudad Real Public Health Service (Spain) received a report of 20 cases of gastroenteritis in the municipality of Daimiel. We conducted an investigation to determine the cause or causes of the outbreak and to implement control measures. Most of the cases involved young people who visited the municipality's fair. Methods: We carried out a descriptive study and an analytic case-control study. In the descriptive study, all variables of interest available in the medical records were included. In the case-control study, each case was matched with a control by age (plus or minus 5 years), gender, and attendance at the fair. Sixty-five cases and 65 controls were finally included in the study. Samples of foods and stools from food handlers were taken. Results: We found 196 cases, 146 of which were confirmed. The epidemic curve suggested a common source of infection with a short period of activity. The case-control study showed an association between infection and eating potatoes with a sauce at any of the fair's five food stalls (OR = 20.56; 95%CI, 6.15-75.93; p < 0.0001). Logistic regression analysis showed an association with eating potatoes in food stall number 2 (OR = 6.38; 95%CI, 1.70-23.90; p < 0.0059). Neither samples of foods nor stools from food handlers yielded any positive results. However, Shigella sonnei was isolated from stool samples from 20 cases. Conclusions: The epidemiological study suggested that the most probable cause of the outbreak was a sauce, handmade with garlic, milk, and oil and served with the potatoes.
