Dengue is a viral infection spread by mosquitoes. It's widespread in many parts of the world.
In most people the infection is mild and passes in about a week without causing any lasting problems. But in rare cases it can be very serious and potentially life threatening.
There's no specific treatment or widely available vaccine for dengue, so it's important to try to avoid being bitten by mosquitoes when visiting an area where the infection is found.
This page covers:
Symptoms of dengue
Symptoms of dengue usually develop suddenly 4 to 10 days after becoming infected.
Symptoms can include:
- a high temperature (fever), which can reach 40C (104F) or higher
- a severe headache
- pain behind the eyes
- muscle and joint pain
- feeling or being sick
- a widespread red rash
- loss of appetite
The symptoms normally pass in about a week, although you may feel tired and slightly unwell for several weeks afterwards.
In rare cases severe dengue can develop after the initial symptoms.
When to get medical advice
Remember to tell them where you've been travelling.
Go to a local doctor or hospital if you develop symptoms while travelling or living in an area where dengue is common.
There's little a doctor can do to help you recover, but it's important to get a proper diagnosis in case there's another cause of your symptoms.
You may need a blood test to confirm that you have dengue.
Treatment for dengue
There's no cure or specific treatment for dengue. Treatment involves relieving your symptoms while the infection runs its course.
You can usually look after yourself at home.
The following can help:
- take paracetamol to relieve pain and fever - avoid aspirin or ibuprofen, as these can cause bleeding problems in people with dengue
- drink plenty of fluids to prevent dehydration - if you're currently abroad, only drink bottled water from properly sealed bottles
- get plenty of rest
You should start to feel better in around a week, although it may be a few weeks before you feel your normal self again. Get medical advice if your symptoms don't improve.
Where dengue is found
Dengue isn't found in the UK. Cases in the UK only occur in people who've recently travelled to an area where the virus is common.
Dengue is found in parts of:
- southeast Asia
- the Caribbean
- the Indian subcontinent
- South and Central America
- the Pacific Islands
Use the NHS Fit for Travel destination guide to find out if dengue is a risk in a country you're planning to visit.
How dengue is spread
Dengue is spread by infected mosquitoes, usually the Aedes aegypti and Aedes albopictus varieties.
These mosquitoes bite during the day, most often early in the morning or in the early evening before dusk.
They're often found living around sources of stagnant water in built-up areas, such as wells, water storage tanks or old car tyres.
Dengue isn't spread from person to person.
You can get it again if you've had it before, as you'll only be immune to one particular variant of the virus.
There's currently no widely available vaccine for dengue. You can prevent it by avoiding being bitten by mosquitoes.
The following can reduce your risk of being bitten:
- use insect repellent - products containing 50% DEET are most effective, but lower concentrations (15-30% DEET) should be used in children, and alternatives to DEET should be used in children younger than two months
- wear loose but protective clothing - mosquitoes can bite through tight-fitting clothes; trousers, long-sleeved shirts, and socks and shoes (not sandals) are ideal
- sleep under a mosquito net - ideally one that has been treated with insecticide
- be aware of your environment - mosquitoes that spread dengue breed in standing water in urban areas
It's a good idea to speak to your GP, practice nurse or a travel clinic before travelling to get specific advice about what you can do to avoid dengue and other travel illnesses.
In rare cases dengue can be very serious and potentially life threatening. This is known as severe dengue or dengue haemorrhagic fever.
People who've had dengue before are thought to be most at risk of severe dengue if they become infected again. It's very rare for travellers to get it.
Signs of severe dengue can include:
- severe tummy (abdominal) pain
- a swollen tummy
- persistent vomiting and vomiting blood
- bleeding gums or bleeding under the skin
- breathing difficulties or fast breathing
- cold, clammy skin
- a weak but fast pulse
- drowsiness or loss of consciousness
If you have symptoms of severe dengue, call 999 (or the local emergency number if you're abroad) for an ambulance immediately.
'I wouldn't want to repeat the experience of having dengue'
'I wouldn't want to repeat the experience of having dengue'
Hugh Wilson didn't know anything about dengue until he came down with the illness on holiday in Thailand.
"I never seemed to get bitten while I was travelling," says Hugh. "I wasn't really concerned about mosquitoes."
Hugh and his partner were staying in Krabi in southern Thailand when Hugh started to experience symptoms.
"It started off as a mild headache and then fever. I also had a rash of tiny red spots over my shoulders, chest and back.
"The fever was awful, but the worst thing was the headache. It was the worst headache I'd ever had, like torture. Painkillers didn't have any effect and it was worse when I tried to sleep. So I got no sleep at all, which was horrible."
Hugh was staying on a small island only accessible by boat. He suffered for three days and nights before he sought medical help.
"I was first seen by a nurse attached to one of the hotels on the island. She looked at me and said she wasn't equipped to diagnose me. I realised I was going to have to get back on a boat and get help on the mainland. I was too weak to carry my rucksack, so thank goodness my partner was there to help me."
Hugh went to the nearest hospital. The doctors gave him blood tests. At first, they were unable to confirm the dengue virus, but there had been a recent outbreak of the disease.
"They told me to come back in two days if I wasn't feeling any better and to take paracetamol. But that night I just felt awful and went back the next day. They admitted me and did other tests, which confirmed it was dengue.
"Luckily, I didn't have any dangerous complications. They gave me an injection, which I think may have been a muscle relaxant, but the language barrier was difficult to overcome. I just let things happen.
"I felt very relieved that I was in hospital and someone was looking after me."
Hugh stayed in hospital for two nights and three days. He started feeling a lot better after the first day. Doctors monitored his condition. They told him the fever had peaked and the worst was over.
Hugh left hospital feeling much better. "I was incredibly weak for weeks afterwards," he says. "All I could do was wander around and try to keep out of the sun. We went to Bangkok a week later and I collapsed after drinking three pints of beer. It took a while to recover."
Hugh says he'll never be casual about bite protection again. "I wouldn't ever want to repeat the experience of having dengue," he says.
"I wish I'd known more about dengue. The real fear seemed to be malaria. But after I'd had dengue, I found out it's a big problem, but just not as well known as malaria. We had mosquito nets and coils, which we only used at night. We were quite slack about putting on repellent during the day. But now I've learned my lesson."