Chikungunya Outbreaks — The Globalization of Vectorborne Diseases

In 2006, an outbreak of chikungunya fever — an arthralgic disease caused by a mosquito-borne alphavirus — swept over a number of islands in the Indian Ocean (the Comoros, Mauritius, the Seychelles, Madagascar, Mayotte, and Reunion). In Reunion, which has a population of 770,000, there were 265,000 clinical cases (an incidence of 34%), and the disease was implicated in 237 deaths (about 1 per 1000 clinical cases); a recent report by Reunion health authorities indicated that the seroprevalence was 35%, with very few asymptomatic cases. The epidemic had started with outbreaks in Kenya in 2004 and the Comoros early in . . .