Dengue

Cause of dengue

Dengue is a viral disease spread by mosquitoes. There are 4 different dengue virus types dengue-1, dengue-2, dengue-3 and dengue-4.

Symptoms of dengue

Dengue can cause a range of illness, from mild to severe. In most cases, symptoms resolve within one to two weeks.

Typical symptoms of dengue may include:

• fever
• severe headache
• pain behind the eyes
• joint and muscle aches
• nausea and vomiting
• skin rash
• feeling generally unwell or fatigue.

Although rare, a small number of people may develop severe dengue, which is also known as dengue-haemorrhagic fever. This can result in serious complications and even death.

Symptoms of dengue-haemorrhagic fever may include:

• heavy bleeding
• extremely low blood pressure caused by blood loss (shock)
• coma.

People who are infected for a second time are at greater risk of severe dengue.

Diagnosis of dengue

See a doctor immediately if you think you may have dengue. Early diagnosis is important to reduce the risk of complications.

Your doctor will ask about your medical history, including any travel, and will do a physical examination. Blood tests are required to diagnose dengue.

Treatment for dengue

There is no specific treatment for dengue. Medical care manages the symptoms and reduces the risk of complications while the person recovers. Most cases of uncomplicated dengue resolve fully within one to two weeks.

Hospital admission is usually required if the person develops warning signs of severe dengue.

Where dengue commonly occurs

Dengue is the most common mosquito-borne disease Victorians acquire while travelling overseas.

In 2024, the Victorian Department of Health received the most notifications of dengue in any year on record. This was nearly double that of the year before.

Dengue is common throughout tropical and subtropical areas of the following regions and countries:

• Indonesia (including Bali)
• Southeast Asia (such as Thailand, Vietnam, Malaysia and the Philippines)
• Southern Asia (such as India, Sri Lanka and Bangladesh)
• Pacific Islands (such Fiji and Samoa)
• Central and South America
• Africa
• the Caribbean
• China
• the Middle East.

Dengue in Australia

Cases of dengue occur in northern Queensland from time to time when travellers who have been infected overseas return and introduce the virus to the local mosquito population. To date, it is not as common as in other subtropical regions.

How dengue is spread

Mosquitoes contract the virus when they bite an infected person or animal. The mosquito is then infectious for the rest of its life and can spread the virus every time it bites someone else. The mosquito vector of dengue virus is not currently present in Victoria.

Protect yourself from dengue while travelling overseas

The best protection from mosquito-borne diseases is to avoid mosquito bites. The following steps can help protect against dengue and other mosquito-borne diseases.

Check your accommodation is mosquito-proof

Check that your accommodation has:

• fly screens on the doors and windows
• a mosquito net
• outward opening doors and windows
• ceiling fans – to increase internal air pressure.

Spraying insecticide inside of a closed mosquito net before going out in the evenings can help to ensure there are no mosquitoes when you go to sleep. Make sure your mosquito net touches the floor to stop mosquitoes flying inside of the net.

Use mosquito repellent

Mosquito repellents containing picaridin or diethyltoluamide (DEET) as the active ingredient provide the best protection.

Apply mosquito repellent to all exposed skin regularly as directed by the product’s instructions.

• use a thin, even layer, rubbing into all exposed skin to ensure no spots are missed
• reapply repellent after exercising, showering or swimming
• repellent should be applied over sunscreen.

Repellents come in different applications. The best repellents are lotions that can be applied and rubbed into the skin. Other forms include spray for clothing and a roll-on for near and on the face. Consider buying mosquito repellent and 'knock-down' fly spray before you leave Australia as you may not be able to buy your preferred one overseas.

Pack and wear mosquito proof clothing

Pack clothes that are:

• long-sleeved and legged – for maximum coverage
• light-coloured – mosquitoes are attracted to dark colours
• loose-fitting – mosquitoes can bite through tight clothes
• socks and closed-toe shoes
• a hat – mosquitoes can bite through hair.

Mosquitoes are most active at dawn and dusk. Make sure you are wearing protective clothing and repellent during these times.

Protect your children

When mosquitoes are out, dress children in long, loose-fitting clothes. Make sure cuffs around ankles and wrists are firm.

Never allow young children to apply their own repellent. Choose a lower strength repellent (no more than 20% picaridin or DEET) and apply a thin, even layer rubbed into the skin, as required. Avoid applying repellent to your children’s hands, eyes and mouth.

Drape mosquito nets over prams, strollers and infant carriers, ensuring there are no gaps.

Dengue vaccination

Qdenga® is a vaccine that helps protects against dengue. It is now available in Australia for people aged 4 years and over.

Before travelling overseas to countries where dengue occurs, talk to your doctor or travel health provider for advice about vaccination and whether it is suitable for you The vaccine is given as two doses, three months apart.

People who receive the vaccine should continue to follow mosquito bite prevention measures. Avoiding mosquito bites is the most effective way to prevent dengue..

Where to get help

• Australian Centre for Disease Control - Dengue
• Your GP or travel doctor
• Your pharmacist
• Your Local Public Health Unit Tel. 1300 651 160