DENGUE FEVER

In most cases, the dengue virus causes no symptoms or only mild symptoms, which disappear within a few days and up to a week. Classic dengue fever may initially present with flu-like symptoms. Typical symptoms at the beginning include a fever up to 40 degrees, chills and headaches. The headaches are often perceived as a strong feeling of pressure behind the eyes. Additional symptoms include muscle pain and joint pain, which is why dengue fever is also called ‘break-bone fever’. It can also cause a skin rash with small, pale red spots on the body. The lymph nodes can become swollen. It often takes several weeks for the symptoms of classic dengue fever to completely disappear.

A severe form of dengue fever can develop in a very small number of sufferers. Children and people who have already experienced a dengue infection are particularly at risk.

The severe form is accompanied by other symptoms, such as severe abdominal pain, vomiting, shortness of breath and impaired consciousness. Blood clotting disorders typically occur over the course of the disease. Signs of this can be small, pinpoint bleeding on the skin (petechiae) or more severely nosebleeds and internal bleeding.

The severe form of dengue fever can lead to circulatory collapse and organ failure. If dengue fever is detected and treated early, the mortality rate is below 1%. In Germany, severe forms of the disease and dengue deaths are extremely rare.

It usually takes 4 to 7 days from infection to the onset of the initial symptoms. Less often symptoms occur after 3 days or only after up to 14 days. Sufferers cannot transmit the virus themselves to other people. They are therefore not contagious to other people, except in the case of a needle injury, for example.

However, if the infected person is bitten by an Aedes mosquito, the virus can be transmitted to the mosquito. This mosquito can then infect other people through a bite.

The dengue virus can infect people living in tropical or subtropical regions in particular (when travelling in Central America, South America, Southeast Asia or parts of Africa, for instance). The risk of transmission is particularly high around the rainy season. Transmission has already occurred in some European countries too, such as France, Italy, Spain and Croatia. Certain groups of people have an increased risk of a severe case of dengue fever:

• Children under 15 years of age
• People who have already been infected with the dengue virus

Protection against mosquito bites

The best way to protect yourself from dengue fever is to protect yourself from mosquito bites when travelling. The following measures are suitable:

• Wear clothing that covers as much skin as possible.
• Apply mosquito repellent to the skin. If you use sunscreen, let it absorb well before applying the repellent.
• Clothing can also be made more repellent by applying mosquito repellent to it.
• Attach insect screens to windows and doors or use mosquito nets.
• Stay in air-conditioned rooms if possible.

When travelling in the subtropics or tropics, you can unknowingly become infected with dengue viruses without falling ill. In order to keep the risk of transmission in Germany low, travellers returning from regions where the dengue virus is endemic and who are staying in Germany after returning to areas of the country where the Asian tiger mosquito is common should continue to protect themselves from mosquito bites for 2 to 3 weeks in summer and early autumn.

The vaccine Qdenga is available to protect against dengue fever. In November 2023, a recommendation for this vaccine was issued by the Standing Committee on Vaccination (STIKO). The STIKO recommends vaccination only for people aged 4 years and older who have been proven to have been infected with the dengue virus (i.e. infection with dengue viruses has been confirmed by a laboratory) and who

• are planning a trip to a risk area or
• carry out targeted activities with dengue viruses (e.g. in research institutions or laboratories) outside endemic areas.

Vaccination should take place at the earliest 6 months after a laboratory-confirmed infection with the dengue virus.

2 doses of the vaccine at least 3 months apart are required for adequate vaccination protection