Dengue fever

What is Dengue Fever?
Dengue Fever (also known as break bone fever) is a severe, flu-like viral illness that affects infants, young children and adults, but rarely causes death. It is spread by the bite of an infected mosquito and is common throughout the tropics and subtropics. Dengue Fever has increased greatly the last few decades, especially in urban and semi-urban areas. WHO now estimates that there might be as many as 50 million cases worldwide each year. Dengue Fever is a notifiable disease in Ireland.

What are the symptoms of Dengue Fever?
The incubation period (time between being infected and becoming ill) is usually 4 to 7 days after being bitten by an infected mosquito. The illness is generally milder in children and more severe in adults and usually lasts up to 10 days. Full recovery is normal.

The most common symptoms include:

  • Fever
  • Chills
  • Headache
  • Backache
  • Extreme exhaustion

In some cases, the disease may progress to dengue haemorrhagic fever (DHF) or dengue shock syndrome (DSS) both of which can be fatal. These complications are rare however, and are more common in people who live in an area affected by Dengue Fever and have been repeatedly exposed to the virus.

How is Dengue Fever spread?
Dengue Fever is transmitted (spread) by the bite of an infected mosquito. The type of mosquito that causes Dengue Fever tends to bite more during the daytime and at dawn and dusk. It is found mostly throughout the tropics and subtropics and is endemic (common) in about 100 countries. Dengue fever cannot be prevented by vaccination or medicine - the only way to reduce the risk of being infected is by avoiding mosquito bites.

How is Dengue Fever treated?
There is no specific medicine to treat dengue infection. If you think you may have Dengue Fever, you should see your doctor as soon as possible. You should also rest and drink plenty of fluids.

How is Dengue Fever diagnosed?
Your doctor will arrange for you to have a blood test which will show if you have been infected or not.

Have cases of Dengue Fever been diagnosed in Ireland?
Each year a small number of cases of Dengue Fever are reported in travellers returning from an affected area.

Are people in Ireland at risk of Dengue Fever?
Dengue Fever can be brought into Ireland by a traveller who was infected in an affected area. As you can only become infected by being bitten by an infected mosquito, you cannot catch Dengue Fever from another person.

What countries are affected by Dengue Fever?
Dengue fever is present in Asia, the Pacific, the Caribbean, the Americas and Africa.

What do I do if I’m living/working in an area where Dengue Fever is circulating?
If you become ill, you should contact your doctor who will be able to advise you. You should also try to avoid being bitten by mosquitos – see advice below.

What do I do if I am travelling to an area where Dengue Fever is circulating?
The best way for travellers to endemic areas (areas where Dengue Fever is common) to avoid becoming infected is to avoid being bitten by mosquitoes. The list below highlights the best ways of preventing this.

Time: As dengue is associated with a day-biting mosquito, precautions to reduce bites should be taken at all times during the day, and at dawn and dusk.
Risky areas: Avoid areas where mosquitoes are likely to be found, i.e. near water including ponds, outdoor swimming pools, lakes and marshes.
Use mosquito repellents (bug sprays): Spray onto exposed skin whenever you are in an area where mosquitoes may be present. Repellents applied to clothing, shoes, tents, mosquito nets and other gear will increase protection. Your local pharmacist can advise you on the most suitable product to use.
Dress safely: If in areas where mosquitoes are likely, wear long sleeves, long trousers, socks and closed shoes.
Indoors: Mosquito bites can be reduced by air conditioning, insect-proof screens on windows and doors and spraying the room with insecticide (bug spray).
Mosquito nets: Bed nets and cot nets can be used if necessary, as an additional precaution.

Information on protecting yourself and your family against biting mosquitoes is available on the HPSC website.

What do I do if I’m returning to Ireland from an area where Dengue Fever is circulating?
If you become ill when you return to Ireland, you should visit your doctor and let him/her know of your recent travel history.

Last updated: 16 May 2018