Dengue fever

Dengue viruses (a member of the Flaviridae family) are transmitted to humans through bites of infected female Aedes aegypti mosquitoes. These are found mainly in Asia, Africa, Central and South America, where it is a common cause of fever and may be fatal. After an incubation period of 5-6 days there is an abrupt onset of fever, headache, retro-orbital pain and severe myalgia, often with a skin rash. Dengue haemorrhagic fever is a severe form with thrombocytopenia and spontaneous bleeding. The additional signs of circulatory failure (hypotension, tachycardia, poor peripheral perfusion) indicate dengue shock syndrome. Diagnosis during the acute phase is by detection of the virus (by cell culture, reverse transcription PCR) or its components (non-structural protein NS1) in the blood. Treatment is supportive particularly with adequate fluid resuscitation.