Dengue and dengue hemorrhagic fever (DHF) are acute febrile diseases, found in the tropics, with a geographical spread similar to malaria. Caused by one of four closely related virus serotypes of the genus Flavivirus, each serotype is sufficiently different that there is no cross-protection and epidemics caused by multiple serotypes (hyperendemicity) can occur. It is transmitted to humans by the mosquito Aedes aegypti (rarely Aedes albopictus).
The disease is manifested by a sudden onset of fever, with severe headache, joint and muscular pains (myalgias and arthralgias, severe pain gives it the name break-bone fever), leukopenia and rashes, the dengue rash is characteristically bright red and covers most of the body. DHF also shows higher fever, haemorrhagic phenomena, thrombocytopenia and haemoconcentration. In around 5% of cases there is dengue shock syndrome (DDS) and hemorrhage, leading to death. There is no commercially ready vaccine.
The first epidemics occurred almost simulataneously, in Asia, Africa, and North America in the 1780s, the disease was identified and named in 1779. Initially it was rather benign. A global pandemic began in Southeast Asia in the 1950s, by 1975 DHF had become a leading cause of death among children in many countries in that region. Epidemic dengue has become more common since the 1980s, by the late 1990s dengue was the most important mosquito-borne viral disease affecting humans after malaria, there are around 40 million cases of dengue fever and several hundred thousand cases of dengue hemorrhagic fever each year. In February 2002 there was a serious outbreak in Rio De Janeiro, affecting around 1m people but only killing sixteen.\n