Dengue
Dengue is an infection caused by the dengue virus of which there are four different types (serogroups) DENV-1, DENV-2, DENV-3 and DENV-4. The disease is spread through the bite of an infected mosquito. The mosquitoes that spread dengue usually breed in urban areas close to human habitation and are most active during daylight hours. Although unpleasant, dengue is usually a self-limiting illness. However, a small, but significant, number of people can develop more life-threatening infection (severe dengue).
The disease is common in the tropics. Affected areas include the Caribbean, South and Central America, Africa, Asia and the Pacific Islands. Although less common, outbreaks are increasingly being reported outside tropical areas, including in Europe, with locally acquired cases reported in Croatia, France, Italy, Madeira and Spain.
Dengue does not occur naturally in the United Kingdom (UK) but is reported in travellers returning from dengue affected areas. Cases of dengue in UK travellers are increasing, with most reported in travellers who visited Asia, Central and South America or the Caribbean. Country-specific information on dengue is available on our Country Information pages and current dengue outbreaks are listed on our Outbreak Surveillance section.
All travellers to dengue endemic countries are at risk of dengue infection. The chance of becoming infected with dengue is determined by several factors, including destination, length of exposure and season of travel. Risk is thought to be higher during periods of intense mosquito feeding activity (two to three hours after dawn and during the early evening). Travellers, who spend long periods in areas where dengue is common, are at increased risk, but even short-term visitors can be infected.
Approximately 40 to 80 percent of people infected with dengue remain symptom-free. If symptoms do occur, the illness usually begins abruptly with a high fever, and is often accompanied by a severe headache, muscle and joint pain, nausea, vomiting and a rash. Most infections are self-limiting, with a rapid recovery three to four days after the rash appears.
A small number of people develop more severe illness with symptoms which can include dangerously low blood pressure (shock), fluid build-up in the lungs and severe bleeding. There is no specific drug treatment for severe dengue illness, although hospital admission and careful management of fever, fluid balance and pain can help with recovery. If left untreated, severe dengue illness can be fatal. With good medical care, death due to severe dengue is typically less than one percent.
Prevention
Travellers can check our Country Information pages for information on the risk of dengue at their destination. Mosquito bite avoidance is recommended. As dengue is spread by day-biting mosquitoes, particular care with bite avoidance is advised during the day, especially around dawn and dusk.
A vaccine, Qdenga®▼ has been licensed in the UK for the prevention of dengue disease in individuals from 4 years of age.
The UK Joint Committee on Vaccination and Immunisation (JCVI) has advised that Qdenga®▼ vaccine can be considered for individuals aged 4 years of age and older who have had dengue infection in the past and are:
- planning to travel to dengue where there is a risk of dengue infection or areas with an ongoing outbreak of dengue
or
- exposed to dengue virus through their work, for example, laboratory staff working with the virus.
Guidance on use of Qdenga®▼ is available in the JCVI minutes February 2024.
Qdenga®▼ is a live vaccine (it contains live, attenuated dengue virus) and cannot be given to travellers who are immunosuppressed (have a weakened immune system), pregnant or breastfeeding. This vaccine is also contraindicated (cannot be given) for those with hypersensitivity to any component of the vaccine and for children under four years of age.
Resources
- More detailed information on can be found in our dengue factsheet
- UKHSA: Dengue: guidance, data and analysis
- World Health Organization (WHO): Fact sheets: dengue and severe dengue
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Dengue in USA
On 2 October 2024, the Los Angeles County Department of Public Health reported a locally acquired dengue case in a resident of El Monte. The case had no history of travel to areas where dengue is endemic. It is the fifth case of locally acquired dengue in Los Angeles County in 2024.
Dengue in Italy
As of 3 October 2024, a total of 130 locally acquired dengue cases have been reported in Italy since the start of 2024. A total of 102 cases have now been confirmed as dengue virus type 2 (DENV-2) in the Marche Region. Sporadic cases of locally acquired DENV type 1, 2 and 3 continue to be reported in Abruzzo, Emilia-Romagna, Lombardy, Tuscany and Veneto regions.
Dengue in France
As of 25 September 2024, a total of 68 locally acquired dengue cases have now been reported in France since the start of the year.
Dengue in USA
As of 14 September 2024, a total of 35 cases of locally acquired dengue have been reported in Florida since the start of the year. Most of the cases (24) were DENV-3, 4 cases were DENV-1 and for the remaining 4 cases, the serogroup is unknown.
