How do I recognise yellow fever?

In most people, yellow fever occurs without symptoms. About 1 in 10 infected people become ill. The symptoms can vary greatly, from mild flu to high fever with bleeding. Symptoms may include:

• fever
• headache
• muscle pain
• lower back pain
• nausea
• exhaustion
• dizziness
• reddened eyes
• red tongue
• slow heart rate
• very rarely jaundice

Most people recover after 3 to 4 days. 15 to 25% of patients experience worsening symptoms after a short break from symptoms, such as:

• high fever
• jaundice
• stomach pain, vomiting (blood)
• bleeding from all orifices
• spots on the skin
• limited urination/dark urine
• inflamed heart muscle
• low blood pressure/shock
• onset of coma
• epileptic seizures

Some of the patients with severe symptoms die from yellow fever.

How do I get yellow fever?

Tropical mosquitoes transmit the yellow fever virus. If the mosquito stings a human or animal infected with the virus, the mosquito can also become infected. This can only happen in the first 3 to 5 days of the disease. After that, the mosquito can infect other people or animals by biting them. People do not directly infect other people. The period between an infected mosquito bite and the first symptoms is 2 to 9 days.

How do I prevent yellow fever?

There is a vaccine against yellow fever. This vaccine is given to travellers to countries where yellow fever occurs. In some countries, vaccination against yellow fever is mandatory for travellers. You will need a vaccination certificate to enter the country.

The site of the National Coordination Centre of Travel Advice tells you the countries for which vaccination is recommended and where it is mandatory.

Is yellow fever treatable?

There is no cure for yellow fever. The treatment consists of relieving the symptoms. Someone who has had yellow fever is then immune to the virus.

How often does yellow fever occur?

Yellow fever does not occur in the Netherlands. The yellow fever mosquito is found in Africa, South America, Asia and some parts of Australia and Europe. In Europe, this mosquito is found only on Madeira and in a region of north-east Turkey. The disease only occurs in some tropical regions of Africa and South America. The yellow fever mosquito can also transmit other diseases, such as dengue fever, chikungunya and Zika fever.

In 2017, one patient developed yellow fever in the Netherlands after a trip to Suriname. This was the first report since 1985, when someone brought back yellow fever to the Netherlands after travelling abroad. In 2018, one patient was reported after a trip to Brazil. Most travellers are vaccinated and are therefore protected against the disease.

There is a small chance that the yellow fever mosquito could be carried to the Netherlands by plane or ship. The Netherlands Food and Consumer Product Safety Authority (NVWA) monitors for exotic mosquitoes entering the Netherlands. Mosquito traps are used in places where international transport takes place, such as Schiphol airport, in the seaports and at companies that import second-hand car tyres from countries where the mosquito occurs. Because the Dutch climate is not suitable for the yellow fever mosquito, these mosquitoes cannot establish themselves in the Netherlands.

Another tropical or sub-tropical mosquito that is found in more and more parts of Europe is the tiger mosquito. The tiger mosquito cannot transmit yellow fever.