Surveillance of Chikungunya and Dengue Fever In mainland France, surveillance of chikungunya and dengue fever is part of a single plan to prevent the spread of chikungunya and dengue fever in mainland France. This plan, developed by the Ministry of Health, aims to strengthen entomological and epidemiological surveillance, particularly in areas where Aedes albopictus is present, to prevent and assess the risks of the spread of these two viruses (see directive of April 16, 2015). Poitou-Charentes and Limousin are not geographic areas where the Aedes albopictus mosquito (“tiger mosquito”) is established.The goal of epidemiological surveillance of chikungunya and dengue in mainland France is to prevent or limit the establishment of an indigenous transmission cycle for these viruses. It relies on several components, including the mandatory reporting (DO) of biologically confirmed cases.The following must be immediately reported to the ARS by any appropriate means (telephone, fax) and then notified using the mandatory reporting form: - any case of chikungunya (imported or indigenous) defined by the presence of a sudden-onset fever exceeding 38.5°C, debilitating joint pain, and biological confirmation,- any case of dengue (imported or autochthonous) defined by the presence of a sudden-onset fever exceeding 38.5 °C, at least one pain-related symptom (headache, arthralgia, myalgia, low back pain, retro-orbital pain), and biological confirmation.In 2014, 489 cases of chikungunya—including 478 imported cases and 11 locally acquired cases—and 201 cases of dengue—including 198 imported cases and 3 locally acquired cases—were subject to a DO in mainland France.In 2015, since the start of enhanced surveillance (May 1), 168 suspected cases of dengue or chikungunya have been reported, including 22 confirmed imported cases of dengue and 7 confirmed imported cases of chikungunya, in the 20 departments where the presence of the vector has been confirmed.