Dengue virus has four stereotypes. It is possible to get infected four times as there is no cross-protection. Usually, a repeat dengue infection with a different stereotype virus is found to be severe and life-threatening. Nevertheless, recovery from dengue infection with a stereotype can provide lifelong immunity for that particular stereotype.
Dengue Hemorrhagic Fever (DHF) is a severe form of dengue. It is life-threatening. The following symptoms are associated with DHF: severe abdominal pain, severe vomiting, bleeding through the nose or mouth or in stools, internal bleeding, external bruising on the skin, rashes, severe body pain, breathing difficulty and restlessness.
Without prompt treatment, the condition may worsen to hemorrhagic shock (Dengue Shock Syndrome), and death.