Dengue (dandy fever)

dengue klm health services

Prevent dengue, also known as dandy fever. It is a viral infection, which is caused by a mosquito bite. It used to be rare, but is now the fastest spreading mosquito-borne disease in the world. The disease spreads rapidly mainly over all tropical and subtropical regions.

How do you catch it?

The dengue virus is transmitted by the bite of a mosquito (tiger mosquito). This mosquito broods in stagnant water that collects in objects found in a domestic environment, such as old car tyres, tins, buckets and vases. The dengue mosquito is predominantly active during the day, mainly in the morning and evening hours.

Where does it occur?

Dengue can be caught mainly to the tropical regions of Asia, the islands of the Pacific Ocean, the Caribbean islands, Central and South America, and Africa. Cases have also been reported in Mexico, southern Texas and North East Australia. The risk of dengue is greatest in highly urbanised regions, and less pronounced in rural areas. Dengue epidemics occur mainly during the weeks following the monsoons.

What are the symptoms?

Dengue is similar to the flu and is primarily characterised by a (high) fever. It has a short incubation time (the time between being bitten by the infected mosquito and the manifestation of the first symptoms) averaging between about five to seven days.

The general symptoms of dengue are:

  • a sudden and rapidly rising fever (up to 40 °C or higher), often preceded by shivering
  • headache and pain behind the eyes (retro-orbital pain)
  • muscle-, bone- and joint-aches
  • after a few days, nausea and vomiting, sore throat, coughing and a rash
  • in most cases dengue is not serious and will clear up after about seven days
  • however, some people can feel exhausted for several weeks or even months afterwards

How can you avoid catching dengue?

Of course, preventing mosquito bites is most important, especially in the early morning and afternoon when Aedes mosquitoes are active. Wear covering clothing and use a mosquito repellent based on DEET.

Vaccination against dengue

A vaccine against dengue became available in april of 2023. This vaccine (Qdenga) offers around 80% protection against dengue, but is mainly effective for people who were previously infected with the virus. The reason being that an initial infection usually leads to relatively mild symptoms, while a second infection can lead to more serious complaints. Vaccination ensures that those infected have a 95% chance of avoiding hospitalisation for the disease.

How many vaccinations are necessary?

A vaccination series consists of 2 vaccinations with an interval of 3 months. Between the two vaccinations, it is not allowed to travel to a destination where the risk of dengue infection is high. It is therefore very important to start the vaccination series at least 3 months before departure. If you have already experienced dengue and can show written proof of this during the consultation, in some cases it is allowed to travel to a dengue risk area after the first vaccination. The series still has to be finished after the trip.

Who is not eligible for the Qdenga vaccine?

Based on a study of the Qdenga vaccine, the following groups are not eligible for this vaccine:

  • Children under the age of 4;
  • Pregnant women;
  • Women who are breastfeeding;
  • People with immunodeficiencies (immune diseases).

How long does a vaccination against dengue protect?

The vaccine against dengue (Qdenga) has only been available since april 2023. Therefore it is not (yet) known how long this vaccination protects.

The following general advice applies: prevention is better than cure. The Dengue mosquito is active all day, but is most likely to sting in the early morning after sunrise and in the late afternoon before sundown. Please check all insect repellent measures, ensuring that you are fully prepared for travel.