Dengue fever is transmitted by Aedes aegypti mosquitoes in urban areas. It is endemic in rural Africa and common in adults. The incubation period is 2-3 days, with symptoms including fever, joint pain, headaches, and rash. Joint pain is migratory and most commonly affects the hands, ankles, wrists and feet. Laboratory tests may show leukopenia, thrombocytopenia, and elevated liver enzymes. Recovery takes weeks but joint pain can persist for years in some adults. Treatment is symptomatic with paracetamol and naproxen. A vaccine is currently in trials.