From March 2005 to April 2007 the French overseas department and Indian Ocean island of Réunion was significantly affected by an epidemic of chikungunya. Chikungunya is a vector-spread disease (by the aedes albopictus mosquito) that leads to painful rheumatic symptoms. The disease infected approximately one third of the island's total population of 802,000 inhabitants (Rallu 2009 ). This article is a discussion of local etiological accounts of chikungunya. The primary topic raised by informants was whether chikungunya was a vector- or air-borne disease. Even though informants had access to substantial biomedical information concerning the disease and its transmission, some were convinced by it and others were not. In order to make meaning of the disease, the Réunionese drew on various types of medical knowledge from different health sectors simultaneously. To understand people's experiences with chikungunya, we must account for all of their etiological explanations.