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Dengue

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Dengue



Introduction 

Dengue is a common viral infection spread by mosquitoes. It is widespread in tropical and sub-tropical regions.

Symptoms of dengue include:



a high temperature (fever) that can reach as high as 41C (105.8F)



headache



pain behind the eyes



bone, muscle and joint pain



You should see your GP if you develop a fever or flu-like symptoms within two weeks of returning from an area where the dengue virus is common.

 

What causes dengue?

Dengue is spread by infected mosquitoes – most commonly the Aedes aegypti mosquito.

An infected human is bitten by a mosquito, the infected mosquito then bites another human, and the cycle continues.

The condition is widespread in areas of the world with a high mosquito population and has been spread by the trade in worn car tyres, which collect water where mosquitoes breed. Typically, dengue occurs in areas that have a combination of:



a warm and humid climate



overcrowding and major urban centres



The mosquitoes that spread dengue are rare in England, and cases that develop in the UK occur in travellers who picked up the infection overseas.

Dengue cannot be spread from one person to another.

 

Diagnosing dengue

If you have travelled to a country with dengue and develop symptoms after you return to the UK, go straight to your nearest healthcare professional (either a GP or hospital).

If you go to a local doctor familiar with dengue, they will probably be able to diagnose the condition just by looking at you and asking about your symptoms. Remember to tell them you have been travelling, as other tropical viruses may cause similar symptoms.

Your medical and travel history will be taken and you will be asked about your exposure to mosquitoes.

You will also be given a blood test to see what effect the infection has had on your blood, and to confirm whether the dengue virus is present in your bloodstream.

Treating dengue 

Dengue usually clears up by itself within around one to two weeks.

There are no specific medications to treat the disease, but symptoms can be managed by taking paracetamol, drinking plenty of fluids and resting.

 

Complications

A very small number of people with dengue go on to develop a more serious form of the disease known as "severe dengue". Severe dengue is a potentially fatal complication of dengue that can lead to shock (a sudden drop in blood pressure), bleeding and organ damage.

People who get this complication will need to be admitted to hospital as a precaution.

 

Prevention

There is currently no vaccine for dengue fever, so the best way to prevent catching the infection is to take common sense precautions when travelling in high-risk areas, such as:



wear protective clothing



using a mosquito repellent throughout the day



 

Who is affected

Anyone can develop dengue, and it is estimated that 100 million cases of dengue occur each year worldwide.

There can be sudden outbreaks of cases (epidemics) where thousands of people can become infected in a short space of time.

In 2013, there were 541 reported cases in England, Wales and Northern Ireland. Most of these cases were in people returning from destinations such as India, Thailand and Barbados.

 

Symptoms of dengue 

Symptoms of dengue usually develop 4-10 days after being exposed to the dengue virus.

Symptoms of dengue in adults include a fever (high temperature) of 40C (104F) and at least two of the following symptoms:



severe headache



pain behind the eyes



muscle and joint pain



nausea or vomiting



swollen glands



 

Young children may have a rash, along with a fever.

Symptoms usually pass within a week, but it can take several more weeks to make a full recovery. It's common to feel very tired when recovering from this type of infection.

When to seek medical advice

You should see your GP if you develop a fever or flu-like symptoms within two weeks of returning from an area where the dengue virus is common:



South East Asia



the Caribbean



the Indian Subcontinent



South and Central America



Africa



the Pacific Islands



Australia



There is little your GP can do to speed up the infection's course, but it's important to get your condition diagnosed in case there's a more serious cause of your symptoms.

 

Causes of dengue  

Dengue is spread by infected mosquitoes, usually the Aedes aegypti and albopictus varieties.

Transmission of the dengue virus happens in a cycle. An infected human is bitten by a mosquito, the infected mosquito then bites another human, and the cycle continues.

Aedes aegypti and albopictus mosquitoes

These mosquitoes bite during the day, most often early in the morning, or in the evening before dusk.

These types of mosquitoes are often found in pools of stagnant water near humans – for example, containers near building sites or other discarded human waste. Old car tyres are a particular problem, because water collects inside them, allowing Aedes albopictus mosquitoes to breed.

Rates of dengue are often high in major cities in the developing world that have poor sanitation.

Risk factors

Your risk of catching dengue increases if you spend time living or working in larger towns and cities in the developing world. For example, many aid workers contract dengue at least once in their career.

Areas of the world where the dengue virus is common include:



South East Asia



the Caribbean



the Indian Subcontinent



South and Central America



Africa



the Pacific Islands



Australia



 

Complications

There are four different strains of the dengue virus: DEN 1, DEN 2, DEN 3 and DEN 4. 

Once you are infected by one of the strains, you should develop life-long immunity against that strain, but further infections with a different strain are possible.

If you're infected by a different strain, you have a slightly increased chance of developing more serious complications, such as severe dengue

Growing populations and an increase in global travel have resulted in the virus spreading.

 

Treating dengue 

There is currently no cure for dengue, so treatment involves trying to relieve your symptoms while the infection runs its course.

It is recommended that you:



use paracetamol to relieve symptoms of pain and fever – the use of aspirin or ibuprofen is not recommended, as they can trigger internal bleeding in people with dengue



drink plenty of fluids to prevent dehydration – if you are currently travelling, make sure you only drink bottled water from properly sealed bottles and not tap water



get plenty of bed rest



If you do not notice any improvement in your symptoms after three to five days, you should seek further medical advice.

Getting back to normal

You will feel tired and unwell for a while. Most people recover within two weeks, although it can sometimes take up to six weeks for you to get completely better.

If you are worried about any aspect of your treatment or diagnosis when abroad, see your GP when you get home. Make sure you tell them where you have been, what your symptoms were and what treatment you received.

 

Complications of dengue  

In rare cases, a person with dengue goes on to develop a more serious and potentially life-threatening form of the condition, known as severe dengue.

People who have had dengue before are thought to be the main group at risk of severe dengue when they become infected again. For this reason, it's rare for travellers to develop severe dengue.

The warning signs of severe dengue usually appear three to seven days after the original symptoms, and include:



fever decreasing



an intense and persistent abdominal pain



persistent vomiting and blood in your vomit



rapid breathing



bleeding gums



feeling tired



Another related complication is that people with sever dengue can experience a sudden and severe drop in blood pressure. This is known as dengue shock syndrome.  

 

Symptoms of dengue shock syndrome include:



cold, clammy skin



a weak rapid pulse



dry mouth



reduced flow of urine



fast breathing



If you have any of the symptoms of severe dengue, you should seek immediate medical help to prevent the disease progressing.

Call 999 and ask for an ambulance.

You will probably need to be admitted to hospital and given fluids via a drip into one of your blood vessels to prevent dehydration and stabilise your blood pressure.

With treatment, the vast majority of people make a rapid recovery and are usually well enough to leave hospital after a few days. Without treatment, severe dengue is fatal in up to 40% of cases.

 

Preventing dengue  

There is no vaccine to prevent dengue. The best way to prevent getting the disease is to avoid being bitten by an infected mosquito.

Avoid being bitten by a mosquito by:



using insect repellent to avoid being bitten, especially around dawn and dusk – products containing N-diethylmetatoluamide (DEET) are effective, but products containing this ingredient should not be used in babies younger than two months and in lower concentrations in younger children (20-30% DEET)



wearing loose-fitting but protective clothing – mosquitoes are able to bite through tight-fitting clothes; trousers, long-sleeved shirts, and socks and shoes (not sandals) are ideal



sleeping under a mosquito net to avoid being bitten at night



be aware of your environment – mosquitoes that cause dengue breed in standing water in crowded urban environments; this can range from communal toilets to water that gathers inside a stack of old tyres



 



Dengue