Since April 2005, the department of Réunion has been facing a Chikungunya epidemic. The persistence of active outbreaks despite the end of the 2005 southern winter indicates that the efforts made by the DRASS vector control service and the preventive measures taken were not sufficient to eradicate the virus during this first epidemic episode. In this context, the Minister of Health and Solidarity and the Minister for Overseas Territories requested that a support mission be established with the following objectives (see Appendix 1): - to identify the reasons, including any shortcomings in prevention, that allowed the epidemic to develop; - to establish epidemiological forecasts, assess the risks of an epidemic, and evaluate the possibilities for eradication; - to determine the resources and assess the effectiveness of the vector control methods to be implemented, including communication strategies, as well as the contribution of local authorities, and to make recommendations for improvements; - to assist, as needed, the various local stakeholders in their efforts to prepare for the transfer of vector control activities to the departmental council under the best possible conditions. The mission was led by Gilles DUHAMEL, a member of the General Inspectorate of Social Affairs (IGAS), Dominique GOMBERT of the Integrated Expertise Department of the French Agency for Environmental and Occupational Health Safety (AFSSET), Christophe PAUPY, a medical entomologist at the French National Research Institute for Sustainable Development (IRD), and Dr. Isabelle QUATRESOUS of the International and Tropical Department of the French Institute for Public Health Surveillance (InVS). (R.A.)