In early 2005, a major outbreak of Chikungunya infection struck the Comoros, where more than 5,000 cases were reported between January and March. The virus then spread to other islands in the Indian Ocean, with cases reported in Mayotte and Mauritius. Réunion Island was affected starting in March, and the virus began circulating there in an epidemic manner. This study reviews the epidemiology of Chikungunya disease 10 months after the first cases appeared on Réunion Island, noting that the situation is constantly evolving. It also highlights the existence of neurological forms of the disease that have not yet been described. (Introduction)