Viewpoint: High susceptibility to Chikungunya virus of Aedes aegypti from the French West Indies and French Guiana.

To estimate the vector competence of Aedes aegypti populations sampled from distinct anthropogenic environments in French Guiana, Guadeloupe and Martinique for the strain CHIKV 06.21. F/F females were orally infected at titres of 10 and 10 pfu/ml in blood-meals. Disseminated infection rates (DIR) of mosquitoes were estimated using indirect fluorescent antibody assay on heads' squashes, 7 or 14 days post-infection (pi). At a titre of 10 pfu/ml, DIR ranged from 88.9% to 100.0% and were not significantly different whether assessed at day 7 or 14 pi. At a titre of 10 pfu/ml, DIR observed 7 days pi ranged from 37.6 to 62.0%. Ae. aegypti from French Guiana and French West Indies are highly competent to transmit CHIKV. An evaluation of DIR 7 days rather than 14 days pi is adequate to estimate vector competence. The titre of 10 pfu/ml allows us to distinguish Ae. aegypti populations originating from distinct environments (dense or diffuse housing) by their vector competence. This assessment is a prerequisite to better evaluate the potential risk of Chikungunya outbreaks once the virus is introduced from endemic regions. [ABSTRACT FROM AUTHOR]