Dengue is a mosquito-borne viral infection common in tropical areas, caused by four related viruses (DENV-1 to -4). It's primarily spread by Aedes aegypti mosquitoes.Symptoms range from mild, flu-like illness (high fever, severe headache, muscle/joint pain, rash) to severe dengue, which can be life-threatening due to plasma leakage, bleeding, and organ impairment. Warning signs for severe dengue include severe abdominal pain, persistent vomiting, and restlessness, usually appearing as fever subsides.Diagnosis is based on symptoms, travel history, and blood tests (e.g., NS1 antigen, antibody tests).There treatment is supportive: rest, fluids, and acetaminophen for fever (avoid aspirin/NSAIDs). Severe dengue requires immediate hospitalization for fluid replacement and monitoring.Prevention focuses on mosquito control (eliminating breeding sites in standing water) and personal protection (repellent, protective clothing, screens)