Dengue is an infection caused by the dengue virus of which there are 4 different subtypes (serogroups). The disease is transmitted through the bite of an infected mosquito and although unpleasant dengue is usually a self-limiting illness. A small but significant number of patients will go on to develop more severe life-threatening forms of the disease.
Mosquitoes that transmit dengue usually breed in urban areas close to human habitation and are most active during daylight hours. The disease is common in the tropics, affected areas include: the Caribbean, South and Central America, Africa, SE Asia, Indian sub-continent and the Pacific Islands. Although less common, outbreaks are increasingly being reported outside tropical areas, with locally acquired cases reported in Croatia, France and Madeira. Country-specific information on the risk of dengue can be found in our Country Information pages. Current outbreaks of dengue are recorded in our Outbreak Surveillance section.
All travellers to tropical countries where dengue is endemic are at risk of infection, although determining the actual level of risk is difficult. Travellers who spend a long period in areas where dengue is common are at increased risk. However, even short-term visitors may be exposed to dengue.
Symptoms begin with high fever, often accompanied by a severe headache, muscle and joint pain, nausea, and vomiting. Most infections are self-limiting with improvement in symptoms and rapid recovery occurring three to four days after the onset of the rash. A small number of people will progress to severe dengue. Features may include: dangerously low blood pressure (shock), fluid accumulation in the lungs and severe bleeding. There is no specific antiviral treatment for dengue; treatment aims to manage the symptoms of the disease. If untreated a high proportion of patients with severe dengue may die however with appropriate management most patients make a full recovery.
Travellers should be aware of the risk of dengue in the destination to be visited. There is no vaccine to prevent dengue. Prevention is by minimising mosquito bites. Particular vigilance with bite precautions should be taken around dawn and dusk.