Dengue Fever

Updated: November 2, 2006

The Public Health Agency of Canada (PHAC) continuously monitors the global dengue situation. Dengue fever (DF) is an acute viral illness that is spread by the bite of an infected mosquito. PHAC reminds travellers that dengue fever is common in many tropical and subtropical parts of the world. Travellers who visit countries where dengue is endemic (i.e., common) should be aware that the risk of contracting dengue fever exists year-round and that outbreaks can occur at any time. There are specific measures travelers can take to avoid being stung by mosquitoes in areas where dengue occurs - see ‘Recommendations' below.

Dengue in the Americas and the Caribbean

The Pan American Health Organization (PAHO) is reporting that several countries in the region are experiencing dengue fever activity. The following countries are reporting year-to-date case numbers that are higher than those reported for all of 2005: Brazil, Dominican Republic, El Salvador, Paraguay, and French Guyana.

Confirmation of Outbreak in Cuba-
Further to the Agency's October 13 th, 2006, advisory on Dengue Fever, outbreaks in Cuba have now been confirmed in four out of the country's fourteen provinces. Information on case numbers and the geographic distribution of cases is not available at this time. Cuban public health authorities have undertaken intensive insect control measures including mosquito fumigation and active case detection.

For additional information on dengue fever activity in the Americas , visit the Pan American Health Organization's Dengue Fever page at: http://www.paho.org/english/ad/dpc/cd/Dengue.htm

Source: Pan American Health Organization (PAHO)

Dengue in South East Asia

Dengue fever is widespread throughout South East Asia and activity occurs regularly in eight of the regions eleven countries. Although annual case incidence figures are officially reported to the World Health Organization, the current status of dengue activity in the countries of this region is not always readily available through official government sources.

According to the World Health Organization Regional Office for South East Asia:

• Indonesia, Thailand, and Myanmar are considered to be highly-endemic areas where transmission occurs year-round;
• India and Sri Lanka report moderate case activity with peak transmission generally occurring between July and October;
• Bangladesh, Maldives and Timor-Leste report relatively low case activity; and
• Bhutan reported its first outbreak in 2004.

Increased Activity in India-
At this time, India is officially reporting increased dengue fever activity in several states/union territories. As of October 26, 2006, a total of 7 940 cases of dengue fever, including 130 deaths, have been reported in the following regions: Delhi, Rajasthan, Kerala, West Bengal, Punjab, Uttar Pradesh, Maharashtra, Gujarat, Haryana, Tamil Nadu, Andhra Pradesh and Karnataka.

For additional information on dengue fever activity in South East Asia, visit the World Health Organization Regional Office for South East Asia
Dengue Fever page at: http://www.searo.who.int/en/Section10/Section332.htm

Source: World Health Organization Regional Office for South East Asia, Ministry of Health and Family Welfare - India.

Disease Information

Dengue fever (DF) is an acute viral illness of varying severity that is widespread throughout the tropical and sub-tropical regions of the world. DF is spread by the bite of an infected mosquito. Aedes aegypti, the most common mosquito species that transmits the dengue virus, is a day-time biter and lives in close proximity to humans in urban areas.

The illness begins with the sudden onset of flu-like symptoms including fever, headache, muscle aches and joint pain, pain behind the eyes and a faint rash. The fever usually lasts from three to five days, and rarely more than seven days.

For additional information on dengue fever, visit the Public Health Agency of Canada's Disease Information Backgrounder on dengue fever at:
http://www.phac-aspc.gc.ca/tmp-pmv/info/dengue_e.html

Recommendations

Dengue fever is spread by the bite of an infected mosquito. Aedes aegypti, the most common mosquito species that transmits the dengue virus, is a day-time biter and lives in close proximity to humans in urban areas. If you are travelling to dengue-endemic areas, you should take the following personal precautions to reduce your exposure to day-time biting mosquitoes:

• remain in well-screened or completely enclosed, air-conditioned areas;
• wear light-coloured clothing with full-length pant legs and sleeves; and
• use DEET-based products as repellents on exposed skin.

The higher the concentration of DEET in the repellent formulation, the longer the duration of protection. However, this relation reaches a plateau at about 30% to 35%. DEET formulations that are "extended duration" (ED), such as polymers, are generally considered to provide longer protection times, and may be associated with less DEET absorption. Formulations over 30% are not currently available in Canada, although they are available internationally, including in the United States. It should be noted, however, that products sold outside Canada have not been evaluated by Health Canada. Most repellents containing "natural" products are effective for shorter durations than DEET and for this reason are not considered the preferred products for protecting against mosquito bites.

Regulatory agencies in western nations may differ regarding the recommended maximum concentration and application rates of DEET, especially for children. The Committee to Advise on Tropical Medicine and Travel (CATMAT) is satisfied that, for travel outside of Canada where the risk of dengue outweighs the risk of any important adverse reaction to DEET, the threshold for use of DEET should be low.

CATMAT recommends that concentrations of DEET up to 35% can be used by any age group.

For children , alternative personal protective measures, such as mosquito nets treated with insecticide, should be the first line of defense, especially for infants less than 6 months of age. Portable mosquito nets, including self-standing nets, placed over a car seat, a crib, playpen, or stroller help protect against mosquitoes. However, as a complement to the other methods of protection, the judicious use of DEET should be considered for children of any age. Recent medical literature from Canada suggests that DEET does not pose a significant or substantial extra risk to infants and children.

DEET/sunscreen combination products are not generally recommended, because DEET can decrease the efficacy of sunscreens. As well, sunscreens should be used liberally and often while DEET should be used sparingly and only as often as required. If application of both is necessary, the Canadian Dermatology Association recommends that the sunscreen be applied first and allowed to penetrate the skin for 20 minutes, prior to applying DEET.

As a reminder…

The Public Health Agency of Canada routinely recommends that Canadian travellers consult their personal physician or a travel clinic four to six weeks prior to international travel, regardless of destination, for an individual risk assessment to determine their individual health risks and their need for vaccination, preventative medication, and personal protective measures.

PHAC recommends as well, that travellers who become sick or feel unwell on their return to Canada should seek a medical assessment with their personal physician. Travellers should inform their physician without being asked, that they have been travelling or living outside of Canada, and where they have been.

If a fever develops within two weeks of leaving a dengue-endemic area, see a physician and indicate that you have recently travelled to tropical regions . As well, during or following travel to dengue-endemic areas, you should immediately report to a physician any fever that is associated with skin rash, bleeding or easy bruising, particularly if it occurs in children.

Additional information:

• For more information on dengue fever, visit the Public Health Agency of Canada's Disease Information Backgrounder on dengue fever at: http://www.phac-aspc.gc.ca/tmp-pmv/info/dengue_e.html

• For additional information on dengue fever activity in the Americas, visit the Pan American Health Organization's Dengue Fever page at: http://www.paho.org/english/ad/dpc/cd/Dengue.htm

• For additional information on dengue fever activity in South East Asia, visit the World Health Organization Regional Office for South East Asia Dengue Fever page at: http://www.searo.who.int/en/Section10/Section332.htm 

• For a map of areas where the risk of transmission exists, consult the World Health Organization's publication International Travel and Health at: http://www.who.int/ith/en/