DENGUE FEVER Risk factors Factors that put you at greater risk of developing dengue fever or a more severe form of the disease include: Living or traveling in tropical areas. Being in tropical and subtropical areas increases your risk of exposure to the virus that causes dengue fever. Especially high-risk areas are Southeast Asia, the western Pacific islands, Latin America and the Caribbean. Prior infection with a dengue fever virus. Previous infection with a dengue fever virus increases your risk of having severe symptoms if you're infected again.