Given the poor general hygiene conditions and inadequate sanitation, typhoid fever remains an endemic disease in Mayotte, with an estimated incidence of 13.7 cases per 100,000 inhabitants in 2011 (a total of 29 cases confirmed by the laboratory at the Mayotte Hospital Center, CHM). In recent years, clusters of cases have emerged in several locations across the island. Since January 2011, the ARS’s Health Surveillance, Alert, and Management Unit (CVAGS) has been conducting an investigation into each confirmed case to identify undiagnosed secondary cases and the potential source of infection.