FILE- In this undated file photo provided byt he USDA, an aedes aegypti mosquito is shown on human skin. Health officials in the Dominican Republic said this Tuesday April 29, 1014, that the mosquito-borne chikungunya virus has spread widely since making its first appearance in the country. According to the Centers for Disease Control the chikungunya virus is most often spread to people by Aedes aegypti and Aedes albopictus mosquitoes. These are the same mosquitoes that transmit dengue virus. They bite mostly during the daytime. (AP Photo/USDA, File)