Dengue is a viral infection caused by five types of viruses (DENV) 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). In 2013, scientists confirmed the existence of a fifth Dengue virus serotype which could pose a further challenge to developing a vaccine against the infection in humans.
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. Exposure to one type of Dengue virus does not provide immunity to the other three types. Contracting Dengue more than once increases the risk of developing Dengue Hemorrhagic Fever.
Travellers should take 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. There is currently no preventive medication or vaccine against Dengue.
>> For Dengue images, life cycle, and distribution maps, see Infection Landscapes.