All Aedes mosquitoes carry dengue fever

Dengue fever

Pathogen and transmission

Dengue fever is a viral disease and is infected by mosquitoes of the genus Aedes spread, mainly through Aedes aegypti, but also through Aedes albopictus.

Clinical picture

Dengue fever usually occurs 4 to 7 days (rarely 3 to 14 days) after being bitten by an infected mosquito. Infection is asymptomatic in 40 to 80% of cases. However, it can also cause a wide range of clinical symptoms: In classic dengue fever, there is a high fever, headache, pain in the limbs and skin rashes. In rare cases, a severe form has been reported - dengue hemorrhagic fever or dengue shock syndrome - which sometimes leads to death. The pathophysiology of this form is not yet fully understood. However, it often occurs after a renewed infection with a different dengue serotype.

So far there is no effective drug, i.e. the therapy is symptomatic. Symptoms can only be alleviated with antipyretic and analgesic preparations, whereby those based on salicylates are contraindicated due to their blood-thinning effects.

Distribution and frequency

In the last few years the number of dengue fever cases has increased enormously worldwide. While the disease was only registered in 10,000 to 20,000 people annually in the 1960s, there are currently around 50 to 100 million cases per year. According to the World Health Organization (WHO), around 50% of the world's population live in a risk area. But not only the number of cases has increased, but also the geographical spread, for example recently to the USA and to China and Japan. There have also been individual transmissions in Europe (e.g. in Croatia, France and Madeira).

The global increase is reflected in the number of people who have traveled in Switzerland. So far, there has been no transfer in Germany. However, Aedes mosquitoes introduced to Europe are also spreading in Switzerland. The Asian tiger mosquito has already established itself in several regions in this country. Even the Asian bush mosquito, Aedes japonicus, has established itself regionally. This species of mosquito can also transmit dengue under laboratory conditions. There is therefore a general risk of dengue transmission in Switzerland, but this is very low and only exists under certain conditions. To do this, for example, the mosquitoes would have to pick up the virus from a returnee who is infected with dengue.


There is a risk of disease in places where dengue fever occurs. The only preventive measure when traveling to affected countries is currently protection against mosquito bites. It is advisable to wear long-sleeved, insecticide-treated baggy clothes, apply mosquito repellent during the day and evening, and sleep under a mosquito net.

You can obtain further information on the worldwide spread and prevention of the disease from your family doctor or a specialist in travel medicine (see Safetravel).