Shigella outbreak in an elementary school Brote de shigelosis en una escuela de educatión básica

In autumn 1996, children from an elementary school in Santiago were affected by an outbreak caused by Shigella sonnei. Initially 35 children out of 350 beneficiaries of the feeding program got sick. However, in the next five days, 189 new cases appeared. Sixty eight patients submitted stool samples for culture (65 children and 3 food handlers); 20.5% of stool cultures from the children were positive for S. sonnei, and all samples from food handlers were negative. The presentation of the outbreak states a toxiinfection due to S. sonnei, which probably started by ingestion of contaminated food (rate of primary attack 10%) and then person to person transmission (rate of secondary attack 16.9%). To control the outbreak, the personal sanitation rules were enforced as well as those concerning the environment with educational lectures to all the school community and with sanitary in situ control. Five days after beginning the first case, trimethoprim-sulpha was administered to only those sym