Dengue virus. Coloured transmission electron micrograph of dengue virus particles (red), in an enveloping membrane (orange outline). Dengue, or Breakbone Fever, is transmitted to humans by the mosquito, Aedes aegypti, & causes symptoms of aching joints & muscles, fever, sore throat & a rash. A severe form, called dengue haemorrhagic fever, may be fatal. The dengue virus is similar to the Yellow Fever virus: both belong to the flavivirus section of the Togavirus group. Members of this group of RNA-containing viruses are enveloped & possess cubic capsid symmetry. Magnification: x75,000 6x4.5cm size.