Dengue Fever
Dengue is a viral infection spread by day-biting Aedes mosquitoes, common in tropical and subtropical cities. There's no specific treatment and no prophylactic drug, so bite prevention is the main defense. Most cases resolve in about a week, but severe dengue is a medical emergency.
Vaccine
Available
Preventive medication
Not applicable
Incubation
Usually 4–10 days after being bitten.
How it spreads
Spread by Aedes mosquitoes (notably Aedes aegypti), which bite primarily during daylight hours, peaking in early morning and late afternoon.
Where it's a risk
Tropical and subtropical regions worldwide — Southeast Asia, the Pacific, the Caribbean, and Central/South America, increasingly in urban areas.
Seasonal pattern
Peaks during and after rainy seasons, though transmission is year-round in many tropical cities.
Symptoms to watch for
- High fever with severe headache and pain behind the eyes
- Intense muscle and joint pain ("breakbone fever")
- Nausea, vomiting and a skin rash
- Warning signs of severe dengue: abdominal pain, persistent vomiting, bleeding gums, fatigue
How to prevent it
- 1Use insect repellent (DEET or picaridin) during the day
- 2Wear long, loose clothing in mosquito-active areas
- 3Stay in screened or air-conditioned accommodation
- 4Eliminate standing water around lodgings where Aedes breed
Treatment
There's no antiviral cure — care is supportive: rest, fluids, and paracetamol for fever. Avoid aspirin and NSAIDs (ibuprofen), which raise bleeding risk. Severe dengue requires immediate hospital care. A second dengue infection carries a higher risk of severe disease.
Who's most at risk
Travelers to endemic urban and semi-urban areas. Those with a prior dengue infection face higher risk from a second infection.
Frequently asked questions
Is there a dengue vaccine I should get before travel?▼
A dengue vaccine exists but is generally recommended only for people with a confirmed prior dengue infection, because of the higher risk of severe disease on a second infection in the never-infected. Discuss it with a travel-medicine provider; for most travelers, bite prevention is the mainstay.
Why should I avoid ibuprofen with dengue?▼
NSAIDs like ibuprofen and aspirin increase bleeding risk, which is dangerous in dengue. Use paracetamol (acetaminophen) for fever and pain instead, and seek medical care.
Where to watch for it
Country guides where this is a notable risk.
ThailandRelated disease guides
Malaria is a serious, sometimes fatal disease spread by night-biting Anopheles mosquitoes. There's no vaccine for travelers, but prophylactic medication plus bite prevention are highly effective. Symptoms (fever, chills, flu-like illness) can appear weeks to months after travel.
Rabies is a virus transmitted through the bite or scratch of an infected animal — usually dogs. It is almost always fatal once symptoms begin, but entirely preventable with prompt post-exposure treatment. Wash any bite immediately and seek medical care the same day.
Prepare before you go
Build a Trip Kit and we’ll flag Dengue Fever risk for your destinations and match the right prevention to your itinerary.
Build my Trip KitSources: CDC Travelers' Health · WHO International Travel and Health. Last updated 2026-07-31. This page is informational and not a substitute for advice from a travel-medicine provider.