Dengue fever

Published by Bupa's Health Information Team, April 2010.

This factsheet is for people who have dengue fever, or who would like information about it.

Dengue fever is a severe, flu-like illness that is caused by a virus and is spread by mosquitoes. It occurs in many tropical countries and can affect people from the UK who are travelling abroad.

About dengue fever

Dengue fever (also known as breakbone fever) is a viral illness transmitted by a type of mosquito called Aedes mosquitoes. It's found in many countries throughout the world, and is particularly common in South-East Asia, India, the Caribbean, South and Central America, and Africa. If you travel to one of these areas and don't protect yourself against mosquito bites, you may be at risk of catching dengue fever. Most people in the UK who catch dengue fever have travelled to South-East Asia and India.

Symptoms of dengue fever

The exact symptoms you get depend on your age.

In older children, adolescents and adults, the most common symptoms of dengue fever are:

• high fever that comes on quickly and lasts two to seven days
• severe headache
• muscle and joint pain - this is why dengue is often referred to as breakbone fever
• a bumpy, red rash (called a maculopapular rash) that starts on your chest, back or stomach and spreads to your limbs and face
• pain behind your eyes, especially when you move your eyes
• flushing of your face
• feeling sick and vomiting

The symptoms of dengue fever usually begin between five and eight days after an infected mosquito bites you. However, you may not have any symptoms at all.

Young children with dengue often have a fever with a rash, but other symptoms are minor.

These symptoms can also be caused by problems other than dengue fever. If you have any of these symptoms, see your GP and tell him or her where you have travelled to.

Complications of dengue fever

Dengue fever can sometimes develop into a more serious illness called dengue haemorrhagic fever. You are unlikely to get this condition if you are just visiting areas where the disease is common (eg South-East Asia and India). Children under 15 who live in countries where the dengue fever virus is widespread, and people who are infected more than once with different forms of the virus, are more likely to develop dengue haemorrhagic fever.

If you have dengue haemorrhagic fever, you may have bleeding under your skin, from your gums, and from your nose. You may also vomit blood or pass blood in your faeces. If you have any of these symptoms, see your GP.

In more severe cases of dengue haemorrhagic fever, the condition can suddenly worsen and lead to shock (dengue shock syndrome). You may develop severe pain in your abdomen (tummy), keep vomiting, feel irritable and your temperature may suddenly drop. Dengue shock syndrome can be life threatening without proper medical treatment. If you have any of these symptoms, you must seek urgent medical attention.

Causes of dengue fever

Dengue fever is caused by a type of virus called a flavivirus, which is transmitted by infected female Aedes mosquitoes. You can catch the virus if you are bitten by an infected mosquito. Mosquitoes become infected when they bite an infected person and are able to pass on the virus for the rest of their life (two to three months).

There are four different, but closely related forms (serotypes) of the flavivirus that cause dengue fever. Once you have been infected by one form of the virus you're immune against that form for the rest of your life. However, infection with one form of the virus doesn't protect you against catching one of the other three forms. If you're infected a second time, you will be at greater risk of developing dengue haemorrhagic fever.

Diagnosis of dengue fever

Your GP will ask about your symptoms and examine you. You should tell him or her if you have recently travelled abroad.

If your GP suspects you could have dengue fever, he or she may ask you to have a blood test. This is to see whether you have certain antibodies for dengue fever in your blood, and will confirm whether you have the infection. Your GP can also look at your blood tests to see if you have developed dengue haemorrhagic fever or if there is any evidence of another infection such as malaria. Your blood tests will be sent to a laboratory and the results may take several days.

Treatment of dengue fever

Self-help

There isn't a specific treatment for dengue fever, but your body will usually fight off the virus by itself after four to seven days. In the meantime, you should make sure you rest and drink enough fluids. Your GP may suggest that you take oral rehydration therapy (a solution containing salts and other substances) to help prevent you becoming dehydrated. You can take paracetamol to help relieve your pain and reduce your fever, but you should not take aspirin or ibuprofen, as this can worsen any bleeding you may have. Always read the patient information leaflet that comes with your medicine and if you have any questions, ask your pharmacist for advice.

It can take some time to recover from dengue fever. At first, you may feel tired and depressed, and lose your appetite. However, you should be back to normal within several weeks.

Hospital treatment

If you're severely dehydrated, have severe symptoms of dengue haemorrhagic fever or your symptoms suddenly become worse, you will need to be admitted to hospital. In hospital, you will be given fluids via a drip in your arm to make sure you don't become dehydrated. Most people make a full recovery if they receive appropriate treatment.

Prevention of dengue fever

At present, there are no vaccines that can stop you from being infected by any of the four types of dengue virus. The only way to prevent catching dengue fever is to protect yourself from getting bitten by mosquitoes. Advice for avoiding mosquito bites is as follows.

• Wear light-coloured, loose-fitting, protective clothing that covers as much of your body as possible.
• Use an insect repellent on areas of your skin that are exposed and on your clothing - especially around loose parts such as collars or cuffs. Repellents containing a chemical known as DEET (N, N-diethylmetatoluamide) are thought to be most effective.
• Use plug-in devices, which have insecticides in them, to kill mosquitoes.
• Sleep under a mosquito net to avoid being bitten at night.
• Avoid areas where the mosquitoes breed (normally in standing water in domestic containers, around urban areas). You can also remove such sources of water or cover them to prevent access by mosquitoes.

It's most important to follow these precautions around dawn and dusk, as this is when the Aedes mosquito is most active. However, it's important to remember that the Aedes mosquito can bite at any time of the day or night, so making sure you always take the necessary precautions can help to reduce your risk of catching dengue fever.

For answers to frequently asked questions on this topic, see Common questions.

For sources and links to further information, see Resources.