Overview
Dengue (DENG-gey) fever is an illness from mosquito bites that happen in tropical and subtropical areas of the world. Mild dengue fever causes a high fever and flu-like symptoms. A more serious form of dengue fever, called dengue hemorrhagic fever, can cause bleeding, a sudden drop in blood pressure and death.
There are millions of cases of dengue fever around the world each year. Dengue fever is most common in Southeast Asia, the western Pacific islands, Latin America and Africa. But the condition has spread to new areas, including parts of Europe and the United States.
Researchers are working on dengue fever vaccines. For now, in areas where dengue fever is common, the best ways to prevent infection are to keep from getting mosquito bites and to take steps to cut the number of mosquitoes in the area.
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Symptoms
Many people with dengue fever have no symptoms.
When symptoms do happen, they most often begin 4 to 10 days after a bite from an infected mosquito. The symptoms often are thought to be symptoms of another illness, such as the flu.
Dengue fever causes a high fever of 104 degrees Fahrenheit (40 degrees Celsius). Other symptoms may include:
- Headache.
- Muscle, bone or joint pain.
- Upset stomach.
- Vomiting.
- Pain behind the eyes.
- Swollen glands.
- Rash.
Most people get over dengue fever within a week or two. But they may feel tired for a few weeks. For some people, symptoms get worse and can become life-threatening. This is called severe dengue fever, dengue hemorrhagic fever or dengue shock syndrome.
This severe form of dengue fever happens when the infection harms blood vessels and causes them to leak. The number of clot-forming cells, called platelets, in the bloodstream drops. This can lead to shock, bleeding inside the body, organ failure and death.
Severe dengue fever is a life-threatening emergency. Warning signs come on quickly. These signs most often begin the first day or two after the fever goes away. They may include:
- Bad stomach pain.
- Repeat vomiting.
- Bleeding from the gums or nose.
- Blood in the urine, stools or vomit.
- Bleeding under the skin, which might look like bruising.
- Hard or fast breathing.
- Tiredness.
- Being cranky or restless.
When to see a doctor
Severe dengue fever is a life-threatening medical emergency. Seek medical help right away if you've recently visited an area where dengue fever is known to happen, you have had a fever and you get any of the warning signs of severe dengue fever.
If you get a fever and mild symptoms of dengue fever after recent travel, call your healthcare professional.
Causes
The cause of dengue fever is one of four types of dengue viruses. You can't get dengue fever from being around an infected person. Instead, bites from an infected mosquito spread dengue fever.
The two types of mosquitoes that most often spread dengue viruses are common in and around places where people live. A mosquito gets the virus from biting a person who has dengue fever. Other people bitten by the mosquito then get the infection.
After you get over dengue fever, you have immunity to the type of virus that you had, so you can't get that type of virus again. But you can get infected with one of the other three dengue fever virus types. Your risk of getting severe dengue fever rises if you get infected with another type of dengue fever.
Risk factors
You have a greater risk of getting dengue fever or a more severe form of the infection if:
- You live or travel in tropical areas. Being in tropical and subtropical areas raises the risk of getting exposed to the virus that causes dengue fever. Very high-risk areas include Southeast Asia, the western Pacific islands, Latin America and Africa.
- You have had dengue fever in the past. Having had dengue fever in the past raises the risk of bad symptoms if you get dengue fever again.
Complications
Severe dengue fever can cause bleeding inside the body and organ damage. Blood pressure can drop to harmful levels, causing shock. In some cases, severe dengue fever can lead to death.
People who get dengue fever during pregnancy may spread the virus to the baby during childbirth. Also, having dengue fever during pregnancy raises the risk of preterm birth, low birth weight or fetal distress.
Prevention
Vaccine
In areas of the world where dengue fever is common, one dengue fever vaccine (QDenga) is available for people ages 6 to 16. The vaccine is given in two shots at least three months apart. People up to age 60 in those areas can get the vaccine if they have other health issues that put them at higher risk of severe dengue fever.
Prevent mosquito bites
The World Health Organization stresses that the vaccine alone won't lower the number of cases of dengue fever in areas where the illness is common. Preventing mosquito bites and managing the mosquito population are still the main ways of preventing the spread of dengue fever.
If you live in or travel to an area where dengue fever is common, these tips may help lower your risk of mosquito bites:
- Stay in air-conditioned places or housing that has screens on all the windows and doors. The mosquitoes that carry the dengue viruses are most active from dawn to dusk. But they also can bite at night.
- Wear clothing that covers your skin. When you go into areas where there are many mosquitoes, wear a long-sleeved shirt, long pants, socks and shoes.
- Use a substance that keeps mosquitoes away, called repellent. You can put a repellent called permethrin on your clothing, shoes, camping gear and bed netting. You also can buy clothing that has permethrin on it. For your skin, use a spray, cream, lotion or stick with at least 10% DEET.
Give mosquitoes fewer places to breed. The mosquitoes that carry dengue viruses mainly live in and around houses. They breed in standing water that can collect in such things as used car tires. You can help lower the number of mosquitoes near your house by getting rid of places where they lay their eggs.
At least once a week, empty and clean containers that hold standing water, such as planting containers, animal dishes and flower vases. Keep standing water containers covered between cleanings.