Dengue Fever: Global Update

Released: March 18, 2009

• Travel Health Notice
• About Dengue Fever
• Where is Dengue Fever a concern?
• Recommendations to Travellers
• Don't Forget...
• Other Related Information

Travel Health Notice

Outbreaks caused by four types of the dengue fever virus have increased in the past 25 years.  About 40% of the world's population live in areas where there is a risk of dengue fever.

The Public Health Agency of Canada (PHAC) recommends that travellers protect themselves from mosquito bites when travelling to areas where dengue fever may occur . 

About Dengue Fever

Dengue fever is the most common viral disease spread to humans by mosquitoes.  Dengue fever can cause flu-like symptoms.  In some cases it leads to dengue haemorrhagic fever, which can be fatal. There is no vaccine or medication that protects against dengue fever.

Symptoms

• Most commonly take 4 to 7 days to appear.
• Usually include flu-like symptoms such as high fever, severe headache, pain behind the eyes, joint and muscle pain, rash. 
• It is common for some people to show no symptoms. 
• In more severe cases, people with dengue virus infection (approximately 1%) may develop dengue haemorrhagic fever. 
• Individuals with Dengue haemorrhagic fever also experience fever, but their condition can deteriorate suddenly.  This can cause bleeding under the skin, severe abdominal pain and vomiting.
• Dengue haemorrhagic fever can lead to shock.  With proper medical care, only 1% of cases will result in death. 

Transmission

• Dengue fever is spread to humans through the bite of an infected mosquito, particularly Aedes aegpyti.
• Mosquitoes that carry dengue virus breed in standing water that is often found near inhabited areas. They generally bite humans during the daytime. 
• Travellers who spend long periods of time in endemic areas are at greater risk of being infected.  Aid or humanitarian workers also face a higher risk of getting dengue fever. 
• Travellers who stay in the homes of friends and relatives, where there may not be as much protection against mosquito bites, also face a higher risk.

Where is dengue fever a concern?

Dengue fever occurs in most tropical and subtropical areas of the world, predominantly in urban and semi-urban areas. 

Dengue is widespread in regions of Central and South America and South and South-East Asia as well as in Africa.

For a map outlining the regions where there is a risk of dengue transmission, please see the World Health Organization Countries/Areas at risk of dengue transmission 2008.

Recommendations for Travellers

It is recommended that you:

1. Protect yourself from mosquito bites particularly two to three hours after dawn and during the early evening:
   1. Cover up:
      1. Wear light-coloured, long-sleeved, tucked-in shirts, long pants, shoes (not sandals), and a hat.
   2. Use insect repellent on exposed skin:
      1. Insect repellents that contain DEET are the most effective;
      2. Use as directed by the manufacturer;
      3. Do not apply to cuts, scrapes, abrasions or irritated skin;
      4. Do not spray directly on your face;
      5. Wash your hands after you apply insect repellent to avoid contact with your lips and eyes;
      6. Do not use products that contain both insect repellent and sunscreen;
      7. If you want to use sunscreen and an insect repellent with DEET, apply the sunscreen first. Let it soak into your skin for about 20 minutes, then apply repellent with DEET;
      8. Wash off repellent at the end of the day, before you go to bed.
   3. Consider your accommodations:
      1. Stay in a well-screened or completely enclosed air-conditioned room.
   4. Apply a permethrin insecticide to mosquito netting for greater protection:
      1. Permethrin-treated clothing is effective for up to two weeks or six washings. Although permethrin isn't available in Canada, travel health clinics can advise you how to purchase permethrin and pre-treated gear before or during your trip. This could be considered for playpens, cribs or strollers to protect babies under six months of age.

More information on precautions to take to avoid mosquito bites while travelling…

Don't Forget..

1. Consult a doctor, nurse or health care provider or visit a travel health clinic at least six weeks before you travel.
2. What to do if you get sick when you are travelling.
3. What to do if you get sick after you return to Canada.
4. Know what vaccines you need and when to get them.

Other Related Information

• Disease Information Backgrounder on Dengue Fever from the Public Health Agency of Canada
• The Committee to Advise on Tropical Medicine and Travel (CATMAT) – Statement on Personal Protective Measures to Prevent Arthropod
• World Health Organization - Dengue and dengue haemorrhagic fever fact sheet

• Well on Your Way - A Canadian's Guide to Healthy Travel Abroad