Dengue Fever is a viral infection spread to humans primarily by the bite of female Aedes mosquitos. They are active in both rural and urban areas, especially during the rainy season. Dengue is a growing problem in many parts of the world, with the number of cases rising into the tens of millions annually. It is now considered endemic in tropical regions of Africa, the Americas, Asia, the Caribbean, and the Pacific Islands.
Victims typically experience a sudden high fever, headache, and intense body pain about 5-8 days after being bitten by an infected mosquito. A measles-like rash near day 3 of the fever can help distinguish Dengue from other tropical illnesses. The acute illness usually concludes on its own after about a week, but fatigue and depression can last for weeks or months.
A rare but severe form of Dengue may occur in people who have been infected with one strain of Dengue virus and are subsequently infected by a different strain (there are four strains). Called Dengue Hemorrhagic Fever, this syndrome begins with high fever, abdominal pain and vomiting. The most severe untreated cases can progress to spontaneous bleeding, shock and death. Repeated infections increase risk of death. It ordinarily affects only people who live in endemic areas, but there have been cases reported in travelers.
There is no vaccine against Dengue, so it is vital to follow insect precautions when visiting areas where it occurs. Many people routinely take preventive measures against insects between dusk and dawn, when mosquitoes typically bite. The Aedes mosquitoes that are primarily responsible for spreading Dengue are most active during the day, especially in the early morning and late afternoon. They are common in urban areas where they breed outdoors or indoors in man-made containers filled with water. Travelers to endemic areas should make use of repellents (30% DEET) and other preventive measures at all times.