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Dengue Fever
December 2009
Dengue Fever
What is 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.
Cause
Dengue fever can be caused by one of four types of dengue virus.
Risk to Travellers
All travellers are at risk if going to a destination where dengue occurs.
Depends on your country of destination, duration of stay, time of year, what you do when you are travelling, and where you stay during your travels.
Higher during the daytime (2 to 3 hours after dawn and during the early evening). Mosquitoes bite at any time during the day, especially indoors, in shady areas, or when it is overcast.
Risk is low for travellers who stay only a few days in air-conditioned hotels with well-kept grounds and who participate in outdoor activities during non-peak biting periods.
Risk is increased for those spending longer periods of time in endemic areas, and who stay in the home of friends and relatives. Aid or humanitarian workers also at a higher risk.
Severity
Most people recover from dengue fever after a few days.
Dengue fever may progress to dengue haemorrhagic fever which may lead to shock and death.
Prevention
There is no vaccine for dengue fever. The best way to protect yourself is to follow personal protective measures to avoid mosquito bites.
Treatment
There is no specific treatment for dengue fever but medical care can improve patient outcomes.
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.
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.
Dengue is expanding:
- In 2009, dengue appeared for the first time in Cape Verde, Africa, and for the first time in 40 years in Florida, USA.
- Northern Australia (Queensland) recorded their worst outbreak in 50 years.
- Both Mexico and the Dominican Republic reported large outbreaks this year.
A map of the areas where dengue occurs 
is on the website of the World Health Organization.
Related Travel Health Notices
Recommendations for Travellers
It is recommended that you:
- Protect yourself from mosquito bites particularly two to three hours after dawn and during the early evening:
- Cover up: Wear light-coloured, long-sleeved, tucked-in shirts, long pants, shoes (not sandals), and a hat
- Use insect repellent on exposed skin:
- Of the insect repellents registered in Canada, those containing DEET are the most effective
- Use as directed by the manufacturer
- Do not apply to cuts, abrasions or irritated skin
- Do not spray directly on the face
- Wash hands after application, to avoid contact with lips and eyes
- When using sunscreen: do not use insect repellent and sunscreen combination products
- If application of sunscreen and repellent with DEET is required, apply the sunscreen first and let it soak into the skin for about 20 minutes, then apply repellent with DEET
- After returning indoors, wash off repellent.
- Sleep under a bed net, preferably treated with insecticide:
- Ensure the net is intact (no tears or large holes)
- Tuck it under the mattress
- Ensure it is not touching you (or you still may be bitten through the net)
- Consider your accommodations: Stay in a well-screened or completely enclosed air-conditioned room
- Apply a permethrin insecticide to tents and clothing and other travel gear for greater protection
- Permethrin-treated clothing is effective for up to 2 weeks or 6 washings
- Although permethrin is not 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, crib, or strollers to protect young children
More information on precautions to take to avoid mosquito bites while travelling
Don't Forget…
- Consult a doctor, nurse or health care provider, or visit a travel health clinic at least six weeks before you travel.
- What to do if you get sick when you are travelling.
- What to do if you get sick after you return to Canada.
- Know what vaccines to get and when to get them.
Other Related Information
- The Committee to Advise on Tropical Medicine and Travel (CATMAT) – Statement on Dengue
- CATMAT – Statement on Personal Protective Measures to Prevent Arthropod Bites
- World Health Organization – Fact Sheet: Dengue and dengue haemorrhagic fever
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