Dengue fever is an infectious disease caused by one of four types of dengue virus. It is transmitted by the aedes mosquito in tropical and sub-tropical areas of the world, principally in urban areas and mainly during and shortly after the rainy season. The disease is now endemic in more than 100 countries, with some 2,500 million people at risk and an estimated 50 million cases of dengue infection every year. The disease is not fatal, although it can develop into dengue haemorrhagic fever which is fatal in one in five cases without proper treatment. The disease has spread rapidly in recent decades, attributed to a rise in urban populations and the subsequent creation of areas favourable to breeding the predominantly urban aedes aegypti mosquito.
The disease is transmitted through the bite of an infected aedes mosquito and symptoms including a high fever, severe headache and joint and muscle pain appear within 5-6 days. Dengue haemorrhagic fever is a complication and symptoms include those associated with dengue plus bleeding and in severe cases, circulatory failure.
There is no specific treatment for dengue other than careful clinical management, nor is there a vaccine. The only way of preventing and controlling the disease is to target the vector, the aedes mosquito, through environmental control and pesticide use.