Moreover, a seroprevalence study, conducted on a random sample of residents in the village with the largest number of reported cases, shows a 10.2% of protected individuals [18] . Specifically, 82% were symptomatic -similar to 72.3% estimated in Mayotte, Indian Ocean [19] 285% of which satisfied the surveillance case definition, 63% of which were identified by the active surveillance system [18] . Higher prevalences were observed in La Reunion Island and in Mayotte, Indian Ocean, 38.2% and 37.2% respectively [19, 20] .