Dengue and chikungunya fevers are viral illnesses transmitted by day-biting mosquitoes in many tropical areas. While dengue has been long present in the tropics worldwide, chikungunya has been emerging and rapidly spreading in recent years, including to the Caribbean and Latin America.. There are no approved vaccines or pills to prevent these illnesses, and symptoms are similar to those of malaria: high fever and chills. Avoid mosquito bites as much as possible (with repellents and bed nets), and seek medical attention if you develop a high fever. In addition to dengue and chikungunya, other notable mosquito-borne viral infections include West Nile fever and Zika fever.