Dengue is a mosquito-borne viral illness carried by the Aedes mosquito. Dengue fever is the non-severe type and dengue haemorrhagic fever is when the illness is more severe. It is called haemorrhagic because people with it are more likely to have symptoms related to bleeding such as nosebleeds and bleeding gums.
This is a companion discussion topic for the original article at https://patient.info/travel-and-vaccinations/dengue-leaflet