The dengue virus
Dengue is spread by a type of infected mosquito called the Aedes aegypti mosquito. The mosquito bites during daytime hours, particularly around the hours of dawn and dusk.
There are four different strains of the dengue virus: DEN 1, DEN 2, DEN 3 and DEN 4. They can all potentially cause either classic dengue or a more serious form of the disease called dengue haemorrhagic fever (see Dengue - complications).
Growing populations and an increase in global travel have resulted in the transmission of the virus between different populations.
Transmission of the dengue virus happens in a cycle. An infected human is bitten by a mosquito, the infected mosquito then bites another human, and the cycle continues. Jungle animals in Africa and Southeast Asia can also become bitten and infected with the virus, contributing to the spread of the disease.
Risk factors
Factors that increase your risk of being bitten by a mosquito include:
- travelling during the rainy season
- staying in cities of high-risk countries, particularly slums with few or no public health measures
The risk of contracting dengue haemorrhagic fever is increased if you have been infected with a dengue virus before.
