Center for Disease Control and prevention: update: July 27, 2015
CDC has received multiple reports of malaria among US travelers returning from the Dominican Republic. With the exception of Santiago and Santo Domingo cities, the Dominican Republic continues to be a country with malaria transmission. Transmission also occurs in resort areas including popular areas of tourism such as Punta Cana and Puerto Plata.
Travelers to Dominican Republic are reminded to take malaria prevention measures. CDC recommends antimalarial medication for travelers going to the Dominican Republic, outside of Santiago and Santo Domingo cities.
There are many effective preventive antimalarial options for travel to these areas including: atovaquone-proguanil (Malarone), chloroquine (or hydroxychloroquine), doxycycline, or mefloquine.
Malaria and other diseases including dengue and chikungunya are spread by mosquito bites, therefore measures to prevent mosquito bites should be taken regardless of area of travel in the Dominican Republic.
These measures include using insect repellent when outdoors, staying in an air-conditioned or well-screened area, and sleeping under an insecticide treated bed net during the peak biting period for mosquitoes (dusk and dawn).