There are several types of  mosquitoes that breed in the Punta Cana region .  To guard against bites, you should use a mosquito repellent and also use cream and antihistimine to treat any bites. If you are concerned about about Malaria and other diseases carried by the mosquito, you are advised to consult a medical professional in your home country and  not to take the word of other non medical  professionals on this forum.