Dengue fever is a viral infection caused by the dengue virus that is spread by mosquitoes. It's widespread in many parts of the world.
Mosquitoes in Ireland do not spread the dengue virus. But you could catch it if you visit or live in Asia, the Americas or the Caribbean.
The infection is usually mild and passes after about 1 week and does not cause any lasting problems. In rare cases it can be very serious and life-threatening.
There's no single treatment or widely available vaccine for dengue.
Try to avoid being bitten by mosquitoes if you visit an area where the infection is found. Do this by using insect repellent or taking other preventative measures.
Symptoms of dengue fever
Symptoms of dengue fever usually develop suddenly, about 5 to 8 days after you become infected.
Symptoms can include:
- a temperature of 38 degrees Celsius or above
- feeling hot or shivery
- a severe headache
- pain behind the eyes
- muscle and joint pain
- feeling sick
- a widespread red rash
- tummy pain and loss of appetite
The symptoms normally pass after about 1 week. But you may feel tired and a little unwell for a few weeks afterwards.
In rare cases severe dengue fever can develop after the initial symptoms.
When to get medical advice
See your GP if you develop a fever or flu-like symptoms up to 2 weeks after visiting a country that has the dengue virus.
Tell the nurse or GP where you've been travelling.
Go to a GP or hospital if you develop symptoms while travelling or living in an area where dengue is common.
There's little a GP 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 fever
There's no cure or single treatment for dengue fever. You can only relieve the symptoms until the infection has gone.
You can usually look after yourself at home.
It may help to:
- take paracetamol for pain and fever – do not take aspirin or ibuprofen. These can cause bleeding problems in people with dengue
- drink plenty of fluids to prevent dehydration
- get plenty of rest
If you're abroad, only drink bottled water from a bottle that was properly sealed.
You should start to feel better after about 1 week. But it may be a few weeks before you feel your normal self again. Get medical advice if your symptoms don't improve.
Where the dengue virus is found
Mosquitoes in Ireland do not spread dengue virus. Cases in Ireland usually happen to people who recently travelled to an area where it is common.
Dengue virus is found in parts of:
- Southeast Asia
- the Caribbean
- the Indian subcontinent
- South and Central America
- the Pacific Islands
How dengue virus is spread
Infected mosquitoes spread dengue virus. The type of mosquito is usually the Aedes aegypti and Aedes albopictus varieties.
These mosquitoes bite during the day. It's usually early in the morning or in the early evening before dusk.
They're often found near still water in built-up areas, such as in wells, water storage tanks or in old car tyres.
Dengue virus is not spread from person to person.
There are 4 types of the dengue virus. You can get it again if you've had it before, as you'll only be immune to one type of the virus.
Preventing dengue virus
There's no widely available vaccine for dengue virus. You can prevent it by avoiding mosquito bites.
Reduce your risk of bites by:
- using insect repellent
- wearing loose clothing
- sleeping under a mosquito net – one treated with insecticide is best
- be aware of your environment – dengue mosquitoes breed in still water in urban areas
Speak to a GP, practice nurse or visit a travel clinic before travelling. They can give you advice about what you can do to avoid dengue fever and other travel illnesses.
Products containing 50% DEET are most effective. Children should us a lower strength (15% to 30% per cent DEET).
Sprays containing DEET must never be used in infants younger than 2 months old. You should speak to your pharmacist for advice.
Mosquitoes can bite through tight-fitting clothes. Trousers, long-sleeved shirts, and socks and shoes (not sandals) are best.
Severe dengue fever
In rare cases dengue fever can be very serious and potentially life threatening. This is known as severe dengue or dengue haemorrhagic fever.
You may be most at risk of severe dengue fever if you have had dengue and become infected again. It's very rare for travellers to get severe dengue fever.
Signs of severe dengue fever can include:
- severe tummy pain
- a swollen tummy
- being sick repeatedly 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 fever, call 999 or 112 immediately. Go to an emergency department or call the local emergency number if you're abroad.
Content supplied by the NHS and adapted for Ireland by the HSE