Color enhanced transmission electron micrograph (TEM) of the Dengue virus (Flaviviridae). The virus is transmitted via mosquitos of the species Aedes aegypti, primarily in the tropics. Dengue virus causes dengue fever and dengue hemorrhagic fever, with estimates of 50 million cases of dengue infection a year. The virus has four strains and no specific treatment or vaccine is available. Magnification: 170,000x.