What is dengue fever?
Dengue fever is a disease spread to humans by mosquito bites, and is caused by one of four types of dengue viruses. It can cause severe flu-like symptoms and in severe cases can be fatal.
There is no vaccine or medication that protects against dengue fever.
What is my risk?
All travellers are at risk in areas where dengue occurs.
The risk is higher during the daytime, particularly around sunrise and sunset. Mosquitoes that can transmit dengue bite even in shady areas, when it is overcast, or if you are indoors.
The risk is lower for travellers who stay only a few days in air-conditioned hotels with well-kept grounds and who participate in outdoor activities during non-peak biting periods. The risk increases for those spending longer periods of time in areas where dengue occurs, including aid and humanitarian workers and/or those who stay in the home of friends and relatives.
A person who recovers from one of the four types of dengue will have lifelong immunity against that particular type but not against the others.
How is it transmitted?
- Dengue fever is spread to humans through the bite of an infected mosquito, particularly the Aedes aegpyti and Aedes albopictus species.
- Mosquitoes carrying dengue typically bite during the daytime, particularly around sunrise and sunset. They breed in standing water and are often found in urban and semi-urban areas.
What are the symptoms?
- The symptoms most commonly appear three to fourteen days after being bitten by an infected mosquito.
- They usually include flu-like symptoms such as high fever, severe headache, pain behind the eyes, joint and muscle pain, nausea, vomiting and a rash.
- It is common for some people to show no symptoms and most people recover from dengue fever after a few days.
- In a small percentage of cases, people with dengue fever develop dengue haemorrhagic fever, also known as severe dengue. Warning signs usually occur three to seven days after the first symptoms, and include a decrease in fever, bleeding from nose or gums, fatigue, severe abdominal pain, persistent vomiting and difficulty breathing.
- Children growing up in risk areas are at a higher risk of severe dengue.
- Severe dengue can lead to shock. With proper medical care, almost all cases will survive.
Can dengue fever be treated?
There is no specific treatment for dengue fever but medical care can help with recovery and the control of symptoms.
- Dengue fever is found throughout the world, but mainly occurs in tropical and subtropical areas.
- It is widespread in regions of Africa, Central and South America, the Caribbean, the Eastern Mediterranean, South and Southeast Asia, and Oceania.
- The World Health Organization (WHO) estimates that over 40% of the world’s population live in areas where dengue viruses can be transmitted.
- A map of the areas where dengue occurs is available on the WHO’s website.
Consult a health care provider or visit a travel health clinic preferably six weeks before you travel.
- Protect yourself from mosquito bites, particularly around sunrise and sunset.
- If you develop symptoms similar to dengue fever when you are travelling or after you return, see a health care provider and tell them where you have been travelling or living.
- Fact sheet: dengue and severe dengue, World Health Organization (WHO)
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