Shigellosis is a bacterial gastrointestinal disease characterized by the onset of feverish diarrhea, vomiting, and abdominal pain. The typical incubation period ranges from 1 to 3 days. The primary reservoir for the bacteria is humans, and it spreads very easily through the fecal-oral route, including via asymptomatic carriers. Food or water previously contaminated by an infected person can also be a source of transmission. On June 21, 2004, a general practitioner alerted the Aude Department of Health and Social Affairs (DDASS) to the occurrence of several cases of diarrhea with stool cultures positive for Shigella sonnei among children living in the same municipality. The Ddass then decided to conduct an investigation in collaboration with the Interregional Epidemiology Unit (Cire) and the Institute for Public Health Surveillance (Invs). (Introduction)