Dengue fever is a viral infection spread by daytime-biting Aedes mosquitoes across the tropics and subtropics. Most travellers prevent it through diligent mosquito-bite avoidance, with a vaccine available for selected travellers who have had dengue before.
How it spreads
Through the bite of infected Aedes mosquitoes, which bite mainly during the day; it is not spread directly between people in everyday contact.
Where it occurs
In more than 100 countries across the tropics and subtropics, including Southeast Asia, the Indian subcontinent, the Pacific, the Caribbean, and Central and South America.
Main symptoms
Sudden high fever, severe headache, pain behind the eyes, muscle and joint pain, nausea, vomiting and a rash, usually 4 to 10 days after being bitten.
Who is most at risk
Travellers visiting affected regions, especially during and after the rainy season, on longer trips or staying in urban and suburban areas.
Is a vaccine available
Yes. The Qdenga vaccine is licensed in the UK but is generally considered only for people aged 4 and over with confirmed evidence of a previous dengue infection.
How to reduce your risk
Diligent all-day mosquito-bite avoidance using DEET repellent, covering up with clothing and sleeping in screened or air-conditioned accommodation.
Dengue fever is a viral infection spread by daytime-biting Aedes mosquitoes in tropical and subtropical regions, causing high fever, severe headache and joint pain, with a small risk of life-threatening severe dengue. Travellers avoid it mainly through diligent mosquito-bite avoidance during the day, using DEET repellent, covering up and sleeping in screened or air-conditioned rooms. A dengue vaccine (Qdenga) is available for selected travellers who have had dengue before. Crewe Travel Clinic in Crewe, Cheshire offers tailored travel health advice and dengue vaccination where appropriate.
Dengue fever is one of the most common mosquito-borne viral infections affecting travellers, with hundreds of millions of cases estimated worldwide each year. It is caused by the dengue virus, of which there are four closely related types (serotypes), and is spread by the bite of infected Aedes mosquitoes, principally Aedes aegypti and Aedes albopictus. These mosquitoes bite mainly during daylight hours, peaking in the early morning and late afternoon, and thrive in urban and suburban areas where they breed in small collections of standing water.
For most people, dengue causes a flu-like illness that resolves within a week or two, but a minority go on to develop a more serious form known as severe dengue, which can be life-threatening and requires urgent medical care. There is no specific antiviral cure for dengue; treatment is supportive, focusing on rest, fluids and careful monitoring. Because of this, prevention is central to staying well, and the cornerstone of protection for travellers is avoiding mosquito bites throughout the day.
A dengue vaccine (Qdenga) is available in the UK for certain travellers, but it is not suitable for everyone and is generally considered only for those with evidence of a previous dengue infection. At Crewe Travel Clinic in Crewe, Cheshire, our travel health team can review your destination, planned activities and medical history, advise on robust bite-avoidance measures, and discuss whether dengue vaccination may be appropriate for you.
Dengue is transmitted to humans through the bite of an infected Aedes mosquito, mainly Aedes aegypti and Aedes albopictus. These mosquitoes are most active during the daytime, with peak biting in the early morning and late afternoon, and they readily breed in urban and built-up areas using small amounts of standing water such as that found in containers, plant pots, tyres and water storage vessels. A mosquito becomes infected after biting a person carrying the virus and can then pass it on to others. Dengue is not spread directly from person to person through everyday contact, although in rare cases it can be transmitted through blood transfusion, organ donation or from a pregnant woman to her baby.
Many dengue infections cause mild or no symptoms, but when illness develops it typically begins suddenly, around 4 to 10 days after being bitten. Common symptoms include a high fever, severe headache, pain behind the eyes, muscle, joint and bone aches (dengue has historically been called "breakbone fever"), nausea, vomiting, swollen glands and a skin rash. Most people recover within one to two weeks. A small number develop severe dengue, which usually appears as the fever begins to settle and is a medical emergency. Warning signs of severe dengue include severe abdominal pain, persistent vomiting, bleeding from the gums or nose, blood in vomit or stools, rapid breathing, restlessness, fatigue and signs of fluid leakage. Anyone who becomes unwell with a fever during or after travel to a dengue-affected area should seek prompt medical assessment and mention their travel history.
Dengue occurs in more than 100 countries across the tropics and subtropics. Risk is present throughout much of Southeast Asia, the Indian subcontinent, the Pacific islands, sub-Saharan Africa, the Caribbean, and Central and South America. Popular destinations with ongoing dengue transmission include Thailand, Indonesia, Vietnam, the Philippines, India, Sri Lanka, Brazil and many parts of the Caribbean. Transmission tends to increase during and after the rainy season when mosquito numbers rise, and large outbreaks can occur. Cases have also been reported in parts of southern Europe, and the geographic range of the mosquitoes is expanding. The risk to any individual traveller depends on the destination, the season, the length of stay and the type of trip.
There is no medication that prevents dengue, so for most travellers protection relies on avoiding mosquito bites throughout the day, since the Aedes mosquito bites mainly in daylight. Recommended measures include applying an effective insect repellent containing DEET (around 50%) to exposed skin, reapplying as directed, and wearing loose, long-sleeved clothing and trousers, ideally treated with permethrin. Staying in air-conditioned or well-screened accommodation, using a mosquito net where rooms are not screened, and reducing standing water around accommodation all help lower the risk. A dengue vaccine, Qdenga, is licensed in the UK and may be considered for some travellers, but current guidance generally limits its use to people aged 4 years and over who have laboratory-confirmed evidence of a previous dengue infection, because of the risk of more severe illness in those who have never had dengue. A travel health consultation is the best way to assess whether vaccination is suitable for you. Antimalarial tablets do not protect against dengue, as dengue and malaria are different diseases, although both are mosquito-borne.
Dengue is spread by the bite of infected Aedes mosquitoes, principally Aedes aegypti and Aedes albopictus. Unlike the mosquitoes that spread malaria, these bite mainly during daylight hours, with peaks in the early morning and late afternoon, and they thrive in urban and suburban areas. A mosquito becomes infected after biting someone carrying the virus and can then pass it on when it bites others.
There is no medication that prevents dengue, so for most travellers protection depends on avoiding mosquito bites throughout the day. Because the Aedes mosquito bites in daylight, bite-avoidance measures may be advised from morning to evening, not only at night. Reducing standing water around accommodation also helps lower the local mosquito population.
Many infections are mild or cause no symptoms, but illness typically begins suddenly around 4 to 10 days after being bitten and usually settles within one to two weeks. A small number of people develop severe dengue, which often appears as the fever starts to settle and is a medical emergency. Anyone who becomes unwell with a fever during or after travel to a dengue-affected area is advised to seek prompt medical assessment and to mention their travel history.
A dengue vaccine, Qdenga, is licensed in the UK, but it is not suitable for everyone. Current guidance generally limits its use to people aged 4 years and over who have laboratory-confirmed evidence of a previous dengue infection, because of the risk of more severe illness in those who have never had dengue. A travel health consultation is the best way to assess whether vaccination may be appropriate for you.
The following vaccinations can help protect against Dengue Fever.
Book an appointment with our travel health team for tailored advice on protecting against Dengue Fever.