Dengue fever is a mosquito-borne viral illness caused by the dengue virus and transmitted primarily by Aedes mosquitoes in tropical and subtropical regions. It typically presents with sudden high fever, severe headache, pain behind the eyes, joint and muscle pain, rash, nausea, and fatigue, and is sometimes referred to as “breakbone fever” due to intense body aches. Most cases are self-limiting and resolve within one to two weeks, but some individuals may develop severe dengue, which can lead to bleeding, low blood pressure, organ impairment, or shock. There is no specific antiviral treatment, so care focuses on supportive measures such as hydration and monitoring for complications. Prevention relies mainly on mosquito control, protective clothing, repellents, and vaccination where available.