In plain words
Dengue is a viral infection spread to people by infected mosquitoes, common in tropical and subtropical climates. Most people have mild or no symptoms, but some develop severe dengue, which can be fatal.
Key facts
- About half the world population is at risk, with an estimated 100 to 400 million infections a year.
- There is no specific treatment. Prevention relies on vector (mosquito) control, and early detection and proper care greatly lower deaths from severe dengue.
Symptoms
Usually begin 4 to 10 days after infection and last 2 to 7 days: high fever (up to 40 C), severe headache, pain behind the eyes, muscle and joint pain, nausea, vomiting, swollen glands and rash. Most people recover in 1 to 2 weeks. People infected a second time are at greater risk of severe dengue, whose symptoms often appear after the fever has gone.
Care and prevention
Treatment is pain management. WHO advises avoiding mosquito bites, especially during the day, and notes severe cases need hospital care.
Sources
- WHO fact sheet, Dengue, published 21 August 2025, read 9 October 2026.
Last reviewed: 9 October 2026. Reviewer: none yet. This page is general education and is not medical advice. Figures are WHO's and may have been updated since.