dengue fever

Dengue (DENG-gey) fever is a mosquito-borne disease that occurs in tropical and sub-tropical regions of the world. Mild dengue fever causes high fever and flu-like symptoms. The severe form of  fever, also called dengue hemorrhagic fever, can cause severe bleeding, a sudden drop in blood pressure (shock), and death.


Many people do not experience any signs or symptoms of dengue infection.

When symptoms do occur, they can be mistaken for other illnesses – such as the flu – and usually begin four to 10 days after being bitten by an infected mosquito.

Dengue fever causes a high fever — 104 F (40 C) — and any of the following signs and symptoms:

  • Muscle, bone or joint pain
  • Vomiting
  • Headache
  • Nausea
  • Swollen glands
  • Pain behind the eyes
  • Rash

Most people recover within a week or two. In some cases, symptoms worsen and can become life-threatening. This is called severe dengue, dengue hemorrhagic fever or dengue shock syndrome.

Severe dengue occurs when your blood vessels become damaged and leaky. And the number of clot-forming cells (platelets) in your bloodstream decreases. This can lead to shock, internal bleeding, organ failure, and even death.

The warning signs of severe dengue fever — which is a life-threatening one — can develop quickly. Warning signs usually start a day or two after your fever is gone, and may include:

  • Persistent vomiting
  • Blood in your urine, stools or vomit
  • Severe stomach pain
  • Bleeding from your gums or nose
  • Difficult or rapid breathing
  • Irritability or restlessness
  • Bleeding under the skin, which might look like bruising
  • Fatigue

When to see a doctor

Severe dengue fever is a life-threatening medical emergency. Seek immediate medical attention if you have recently visited an area where fever is known to occur, you have a fever and you get any warning signs. Warning signs include severe stomach pain, vomiting, difficulty breathing, or blood in your vomit, nose, stools,or gums.


Dengue fever is caused by any one of four types of dengue virus. You cannot get fever by being around an infected person. Instead fever is spread through mosquito bites.

The two types of mosquitoes that often transmit the dengue virus are common both in and around human habitats. When a mosquito bites a person infected with the dengue virus, the virus is transmitted to the mosquito. Then, when an infected mosquito bites another person, the virus enters that person’s bloodstream and causes infection.

After recovering from dengue fever, you have long-term immunity to the type of virus that infected you – but not to the other three dengue fever virus types. This means that you may be re-infected in the future with one of the other three virus types. Having  fever for the second, third or fourth time increases your risk of developing severe fever.


Severe dengue fever can cause internal bleeding and organ damage. Blood pressure can drop to dangerous levels, which can lead to shock. In some cases, severe fever can cause death.

Women who get fever during pregnancy may be able to transmit the virus to the baby during childbirth. Additionally, women whose babies get dengue fever during pregnancy have a higher risk of premature birth, low birth weight or fetal distress.



In areas of the world where dengue fever is common, a vaccine (Dengvaxia) is approved for people ages 9 to 45 who have already had dengue fever at least once. The vaccine is given in three doses over the course of 12 months.

Prevent mosquito bites

If you live in or travel to an area where dengue fever is common, these tips may help reduce your risk of mosquito bites:

  • Wear protective clothing. When you go into mosquito-infested areas, wear a long-sleeved shirt, long pants, socks and shoes.
  • Stay in air-conditioned or well-screened housing. Mosquitoes that carry the dengue virus are most active from dawn to dusk, but they can also bite at night.
  • Reduce mosquito habitat. Mosquitoes carrying the dengue virus typically live in and around homes, breeding in standing water that can accumulate in things like used automobile tires. At least once a week, empty and clean containers that contain standing water, such as planting containers, animal dishes, and flower vases. Keep pots of standing water covered between cleanings.
  • Use mosquito repellent. Permethrin can be applied to your clothing, shoes, camping gear and bed netting.

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