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Dengue Fever

Topic Overview

What is dengue fever?

Dengue (say "DEN-gay") fever is a disease caused by a virus that is carried by mosquitoes. Mild cases cause a rash and flu-like symptoms. Some people, especially children, can get more serious forms of the illness (severe dengue).

What causes dengue fever?

Dengue fever is spread through the bite of mosquitoes that carry the virus. These mosquitoes bite during the day. The biggest risk is at cooler times of the day like sunrise or late in the afternoon. The mosquitoes breed in standing water, usually in cities or towns. The virus cannot spread from person to person through casual contact. People who have dengue fever should be protected from mosquito bites. If a mosquito bites an infected person, the mosquito becomes infected with the virus and can pass it to other people.

Dengue is found throughout the tropics and subtropics. It is widespread throughout Central and South America, Africa, Asia, and Oceania. Dengue outbreaks have happened in southern parts of the United States and Hawaii.

What are the symptoms?

The symptoms most commonly appear 3 to 14 days after a person gets bitten by an infected mosquito. They usually include flu-like symptoms such as:

  • High fever.
  • Severe headache.
  • Pain behind the eyes.
  • Joint and muscle pain.
  • Nausea and vomiting.
  • Rash.

It is common for some people to show no symptoms and most people recover from dengue fever after a few days. In rare cases, people with dengue fever develop severe dengue. Warning signs usually happen 3 to 7 days after the first symptoms, and include a decrease in fever, bleeding from the nose or gums, fatigue, severe abdominal pain, persistent vomiting and trouble breathing.

If you have symptoms of dengue fever, see your doctor or go to the hospital right away.

How is dengue fever diagnosed?

Your doctor will ask about your symptoms and any recent travel. He or she may order a blood test to confirm whether you have dengue fever.

How is it treated?

There is no medicine for treating dengue fever. Mild cases may be treated at home with rest and plenty of fluids to prevent dehydration. You may take acetaminophen (Tylenol) for pain. But don't take anti-inflammatory medicines like aspirin, ibuprofen (such as Advil or Motrin), or naproxen (such as Aleve). They may increase the risk of bleeding. Be safe with medicines. Read and follow all instructions on the label. People with mild cases of dengue fever usually feel better within 2 weeks.

Severe dengue, the more serious form of dengue fever, usually requires treatment in a hospital. You may need intravenous (IV) fluids to treat dehydration. You also may need a blood transfusion to replace lost blood. You will be closely watched for signs of shock.

How can you prevent dengue fever?

There is no vaccine to prevent dengue fever. And people who have had it before can get it again. Avoid areas where dengue fever and mosquitoes are present if you are at higher risk (e.g., are pregnant, very young, or very old). If you plan to travel to an area where dengue fever is common, make sure to protect yourself against mosquito bites. Here are some guidelines:

  • Use insect repellent with 20-30% DEET (N,N diethylmetatoluamide) or 20% icaridin (1-piperidinecarboxylic acid 2-(2-hydroxyethyl)-1-methylpropylester). Children ages 6 months to 12 years should use products with icaridin instead of DEET.
  • The Committee to Advise on Tropical Medicine and Travel (CATMAT) recommends that children younger than age 6 months use 10% icaridin when travelling in areas where the risk of dengue fever infection is high.
  • The mosquitoes that transmit dengue fever bite during the day, so you need to use repellents whenever you are outside. Spray clothing with an insect repellent, because mosquitoes may bite through thin clothing. (Be aware that DEET can damage plastic items, such as watch crystals or eyeglass frames, and some synthetic fabrics.) Permethrin is not available as an insect repellent in Canada, but travel health clinics may be able to advise you on how to buy permethrin or permethrin-treated gear.
  • Sleep under bed nets (mosquito netting) sprayed with or soaked in an insecticide such as permethrin or deltamethrin.
  • Use flying-insect spray indoors around sleeping areas.

If you are planning international travel, you can learn about the risk of dengue fever in the area you're travelling to by contacting:

  • The Canadian government travel health website on dengue fever:
  • Your local travel clinic.



  1. Centers for Disease Control and Prevention (2010). Dengue: Epidemiology. Available online:
  2. Centers for Disease Control and Prevention (2010). Locally acquired dengue—Key West, Florida, 2009–2010. MMWR, 59(19): 577–581. Also available online:
  3. Centers for Disease Control and Prevention (2007). Dengue hemorrhagic fever—U.S.-Mexico border, 2005. MMWR, 56(31): 785–789. Also available online: [Erratum in MMWR, 56(32):822. Also available online:]


Adaptation Date: 7/31/2019

Adapted By: Alberta Health Services

Adaptation Reviewed By: Alberta Health Services

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