Dengue Fever

What is dengue?

Dengue is a disease caused by any one of four closely related dengue viruses. The viruses are transmitted to humans by the bite of an infected mosquito. In the Western Hemisphere, the Aedes aegypti mosquito is the most important transmitter or vector of dengue viruses.

Who gets dengue?

Dengue is transmitted to people by the bite of an infected yellow fever mosquito or the Asian tiger mosquito, which are found in tropical and temperate zones throughout the world.

How is dengue spread?

For transmission to occur, the mosquito must feed on a person during a 5-day period when large amounts of virus are circulating in the person’s blood; this period usually begins before the person develops illness symptoms. Some people will not have significant symptoms but can still infect mosquitoes. Once the virus enters the mosquito, the virus will then require an additional 8–12 days incubation before it can then be transmitted by mosquito bite to another human. The mosquito remains infected for the remainder of its life, which might be days or a few weeks. In rare cases dengue can be transmitted in organ transplants or blood transfusions from infected donors, and there is evidence of transmission from an infected pregnant mother to her fetus. But in the vast majority of infections, a mosquito bite is responsible.

What are the symptoms of dengue?

The major symptom of dengue is fever along with headache, pain behind the eyes, joint pain, muscle and/or bone pain, rash, mild bleeding of the nose or gums, and easy bruising. About 1 in 20 patients with dengue progress to develop severe, life threatening disease called severe dengue.  Severe dengue can start 1 to 2 days after the fever goes away. Severe dengue may be accompanied by stomach pain or tenderness, persistent vomiting (may include blood), bleeding from nose or gums, and blood in the stool.

How soon after exposure do symptoms appear?

Symptoms of dengue fever infection usually begin 5–7 days after the infectious mosquito bite and typically last 2–9 days.

How is dengue diagnosed?

Dengue can be diagnosed by testing whole blood samples by RT-PCR to isolate the virus (detect the viral RNA). This test is reliable and can detect the virus within two to seven days after illness onset. After seven days of illness onset, serological tests can be used to measure the antibody response to dengue.

What is the treatment for dengue?

Persons suffering from dengue should consult a physician for care. There is no specific medication for treatment of a dengue infection other than supportive care. Persons who think they have dengue should only use pain relievers (analgesics) with acetaminophen. Due to potential for bleeding during dengue infection, Ibuprofen, Naproxen, aspirin or aspirin containing drugs should be avoided. Additionally, one should also rest, drink plenty of fluids to prevent dehydration, and avoid mosquito bites while febrile.

Do people who have been in contact with someone with dengue need to be tested and treated?

Contacts of individuals with dengue should be tested if they exhibit similar symptoms and have a history of travel or mosquito exposure. Dengue is not transmitted directly from person to person, but an infected individual may pass the virus to mosquitoes, potentially exposing others.

How can dengue be prevented?

Prevention of mosquito bites is the best protection against dengue:

  • Use insect repellent containing DEET, picaridin, IR3535 or oil of lemon eucalyptus on exposed skin and/or clothing. The repellent/insecticide permethrin can be used on clothing to protect through several washes. Always follow the directions on the package.
  • Wear long sleeves and pants when weather permits.
  • Have secure, intact screens on windows and doors to keep mosquitoes out.
  • Eliminate mosquito breeding sites around the home by emptying standing water from flowerpots, buckets, barrels, and other containers. Drill holes in tire swings so water drains out. Empty children’s wading pools and store on their side after use.

How can I get more information about dengue?

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Last Updated: February 4, 2025