Dengue fever

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.

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.

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.

Treatment

There is no treatment for dengue fever, but there are ways to ease symptoms.

While recovering from dengue fever, rest and drink plenty of fluids. Call your healthcare professional right away if you get symptoms of severe dengue fever.

Also call your healthcare professional if you get any of the following symptoms. They could mean you've lost too much body fluid. This is a condition called dehydration.

• Less urinating.
• Few or no tears.
• Dry mouth or lips.
• Lack of energy or feeling confused.
• Cold or clammy hands and feet.

You can take acetaminophen (Tylenol, others) that you can get without a prescription to help lessen muscle pain and fever. But for dengue fever, don't take other pain relievers, including aspirin, ibuprofen (Advil, Motrin IB, others) and naproxen sodium (Aleve). These medicines can raise the risk of bleeding from dengue fever.

If you have severe dengue fever, you may need to go to a hospital for:

• Fluid and electrolyte replacement through a vein.
• Checking blood pressure and platelet count.
• Getting donor blood to replace blood loss.