Dengue virus disease

Dengue is caused by infection with one of four closely related viruses, known as DEN-1, DEN-2, DEN-3 and DEN-4. Infection with one of these serotypes gives lifelong immunity to that particular serotype. However, it does not protect you against the other three, so it is possible to catch dengue more than once. Someone who has had dengue once is at greater risk of more severe symptoms if they are infected again.

Symptoms#

The typical signs and symptoms of dengue may include:

• high temperature
• severe headache
• pain behind the eyes
• joint and muscle aches
• loss of appetite
• nausea and vomiting
• skin rash
• generally feeling unwell (malaise)

In most cases, symptoms resolve within one to two weeks.

Although it is uncommon, some people develop severe dengue. Babies, young children, and people who have had dengue more than once are at increased risk of this complication. Warning signs of severe dengue include the typical symptoms together with some or all of the following:

• severe abdominal pain
• restlessness and fatigue
• persistent vomiting (which may include blood)
• nose bleeds and bleeding gums
• shortness of breath

Most people with these symptoms recover fully. A small number go on to have severe dengue, which can include severe bleeding, extremely low blood pressure caused by blood loss (shock), coma and, rarely, death.

Where dengue occurs#

Dengue is common throughout many tropical and subtropical regions, including parts of Africa, the Caribbean, Central America, the Central Pacific, China, India, the Middle East, South America and Southeast Asia. Outbreaks can begin when a traveler carrying the virus introduces it to the local mosquito population in an area where the right mosquitoes live.

How dengue is spread#

Dengue is not passed directly from person to person. Only infected mosquitoes transmit it. A mosquito is thought to pick up the virus when it bites an infected person. It then stays infectious for the rest of its life and can spread the virus each time it bites someone.

Several different kinds of mosquito are suspected of carrying dengue. These mosquitoes are found in tropical and subtropical regions and are not present everywhere, so dengue is mainly a risk in the areas where they live.

Avoiding mosquito bites#

If you are in a dengue-affected area, the best protection is to avoid mosquito bites (which also helps prevent other mosquito-borne diseases). Suggestions include:

• Wear socks, long pants and light-colored, loose-fitting clothing.
• Apply insect repellent to exposed skin and reapply regularly, following the directions for safe use on the label. For children, it can be safer to spray repellent onto their clothes rather than their skin.
• Apply repellent first thing in the morning, because dengue mosquitoes bite during the day, both outdoors and inside homes and buildings.
• Apply a product such as permethrin to your clothes or bedding.
• Use a bed net (mosquito net).
• Stay in air-conditioned accommodation with flyscreens on the windows.

Diagnosis#

See a doctor immediately if you think you may have dengue. Early diagnosis is important to reduce the risk of complications and to help avoid further spread of the virus. Your doctor will ask about your medical history, including any recent travel, and will carry out a physical examination. Blood tests are required to confirm the diagnosis.

Treatment#

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

During this time, your doctor may advise:

• bed rest
• plenty of fluids
• medication to reduce fever, such as paracetamol (do not take aspirin, because of its blood-thinning properties)

Hospital admission is usually required if the person develops warning signs of severe dengue. Treatment for these complications may include intravenous fluids and replacement of lost electrolytes.

Key points#

• Dengue is caused by infection with one of four closely related viruses known as DEN-1, DEN-2, DEN-3 and DEN-4
• Typical signs and symptoms may include high temperature, headache, pain behind the eyes, muscle and joint aches, and a skin rash
• In most cases, symptoms resolve within one to two weeks
• Babies, young children, and people who have had dengue more than once are at increased risk of severe dengue
• Most people who experience these symptoms recover fully

Where to get help#