Dengue fever, also known as breakbone fever, is a mosquito-borne disease caused by the dengue virus, primarily transmitted by the Aedes aegypti mosquito. It presents in three phases: febrile, critical, and recovery, with symptoms including high fever, headache, and muscle pain, while severe cases can lead to complications such as dengue hemorrhagic fever and dengue shock syndrome. Management includes fluid resuscitation, supportive care, and monitoring for warning signs to prevent severe outcomes.