Dengue fever

Dengue can make you very sick, and can be life threatening. There are four types of the virus that cause dengue fever – type 1, 2, 3, and 4. People can become immune to one type once they have been infected with it, but can still get sick from the other types of dengue if exposed because cross-protection immunity among the four dengue virus types is limited.

Transmission and symptoms

Dengue fever is a viral illness spread by infected mosquitoes. There's no specific treatment or widely available vaccine for dengue. It's important to avoid being bitten by mosquitoes when visiting an area where the infection is found.

Catching different types of dengue, even years apart, increase the risk of developing severe dengue. A list of common symptoms and warning signs of severe dengue can be found on the Te Whatu Ora, Health NZ website.

Where to take care

Dengue fever is not endemic (normally present) in New Zealand. It is found in tropical and sub-tropical climates world-wide, including Africa, the Central and South Americas, the Mediterranean region, South-East Asia, and the Western Pacific region including North Queensland (Australia) and Pacific Island countries. The virus is always present in endemic countries but cannot be spread directly from person-to-person.

Currently, there are a number of ongoing outbreaks of dengue fever in South-East Asia, Africa and Pacific countries. Increased holiday and business travel to these countries increases the number of dengue cases and outbreaks around the world. It is especially important for people travelling to these countries to take extra steps to avoid mosquito bites and to know how they can protect themselves and their families from dengue fever.

Prevention advice for travellers

To avoid dengue fever when travelling outside New Zealand in countries where the disease is common, travellers should take precautions to prevent mosquito bites.
Indoors:

• Stay in places with screens on windows and doors. Turn on the air conditioning if you have it as cool air keeps mosquitoes away.
• Use insect sprays indoors when mosquitoes are around.
• Use mosquito coils.

Outdoors:

• Wear a repellent cream or spray, preferably containing diethyltoluamide (DEET). Repellents containing less than 35 percent DEET are recommended because higher concentrations are no more effective – they just work for longer – and in rare cases they can cause poisoning. Other products containing 20-25 percent picaridin and those containing about 30 percent lemon eucalyptus oil (equating to about 20 percent para-methane-diol (PMD)) are also appropriate to use. Repellents should not be applied to wounds, irritated skin, eyes or mouth.
• If you use both sunscreen and insect repellent, apply the sunscreen first and then the repellent.
• Wear protective clothing such as long-sleeved shirts, long pants and hats. Clothing can be treated with repellent.
• Use screens on tents.

What to do if you are concerned about dengue fever

• If you feel unwell during your trip or in the first three weeks after your return, you are advised to seek immediate medical advice and tell the doctor about your travel.
• Drink plenty of fluids.
• Use paracetamol against fever and pain. Avoid aspirin and ibuprofen as they can increase the risk of bleeding from dengue infection. 

Useful links

• Te Whatu Ora, Health NZ - avoiding mosquito bites while travelling
• Healthmap.org - current worldwide dengue outbreaks
• World Health Organisation (WHO) - dengue and severe dengue