Dengue is a viral infection caused by four types of viruses (DENV-1, DENV-2, DENV-3, DENV-4) belonging to the Flavivirdae family. The viruses are transmitted through the bite of infected Aëdes aegypti and Aëdes albopictus female mosquitoes that feed both indoors and outdoors during the daytime (from dawn to dusk). The mosquitoes thrive in areas with standing water, including puddles, water tanks, containers and old tires. Lack of reliable sanitation and regular garbage collection also contribute to the spread of the mosquitoes.
The viruses are present in tropical and subtropical areas of Central America, South America, Africa, Asia, and Oceania. All travellers are at risk during epidemics. Long-term travellers and aid or missionary workers going to areas where Dengue is endemic are at higher risk. Dengue occurs in urban and suburban settings with higher transmission rates happening during the rainy season.
In some cases, Dengue infection is asymptomatic (persons do not exhibit symptoms). Those with symptoms get ill between 4 to 7 days after the bite. The infection is characterized by flu-like symptoms which include a sudden high fever coming in separate waves, pain behind the eyes, muscle, joint, and bone pain, severe headache, and a skin rash characterized by bright red spots.
The illness may progress to Dengue Hemorrhagic Fever (DHF). Symptoms include severe abdominal pain, vomiting, diarrhea, convulsions, bruising, and uncontrolled bleeding. High fever can last from 2 to 7 days. Complications can lead to circulatory system failure and shock, and can be fatal (also known as Dengue Shock Syndrome). If you are infected with the same Dengue virus serotype you become immune to subsquent infections. However, immunity wanes for the other three serotypes over time which increases your risk of developing Dengue Hemorrhagic Fever.
Travellers should take meticulous measures to prevent mosquito bites during the daytime. Insect-bite prevention measures include applying a DEET-containing repellent to exposed skin, applying permethrin spray (or solution) to clothing and gear, wearing long sleeves and pants, getting rid of water containers around dwellings and ensuring that door and window screens work properly. A vaccine is available for people living in Dengue endemic communities in some countries, but is not commercially available for travellers.
Dengue Fever viruses images, life cycle, and distribution maps
Health risk description last reviewed: March 6, 2016
Country information last updated: May 20, 2016