Dengue in South East Asia

Updated: August 23, 2007

The Public Health Agency of Canada continuously monitors the status of dengue transmission globally.  At this time, a number of countries in South East Asia are experiencing an increase in transmission of dengue fever - a mosquito-borne viral illness.  Dengue is present in many tropical and subtropical destinations and travellers who visit countries where dengue is common (i.e., endemic) should be aware that outbreaks can occur at any time. There is no vaccine that protects against dengue infection. Travellers to these areas are therefore advised to use personal precautions to reduce the risk of day-time biting mosquitoes that spread the disease, see: 'Recommendations' below.

The World Health Organization Regional Office for South-East Asia
(SEARO ) reports that the number of dengue cases has increased in Indonesia, Myanmar and Thailand compared to last year. As of July 2007, Indonesia has reported 102,556 dengue cases as compared to 87,470 cases over the same period last year; an increase of 17%. With 9,578 cases, Myanmar has reported an increase of 10%, and with 27,852 cases, Thailand has reported an increase of 6%.  Many other countries in Asia and the Pacific are also facing an increase in dengue this year.

While dengue fever transmission can occur at any time of year in South-East Asia, there is a seasonal trend, which usually peaks in the months of July and August.  In countries such as India, including the capital, New Delhi, dengue outbreaks begin to increase from August onwards soon after the monsoons.

Source:  World Health Organization - Regional Office for South East Asia
(SEARO)

Disease Information

Dengue fever is the most common mosquito-borne viral disease of humans and is the most common cause of febrile illness in travellers returning from the Caribbean, Central America, and South Central Asia.

Dengue fever (DF) is a severe, flu-like illness that seldom causes death.  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. 

Dengue haemorrhagic fever (DHF), a more severe and potentially deadly form of the disease is characterized by loss of appetite, vomiting, intense abdominal pain, shock and bleeding from the nose or under the skin. The occurrence of DHF may be associated with those either experiencing their second infection, being immuno-suppressed, or being under the age of 15. Dengue haemorrhagic fever can be fatal.

Figure 1:  Dengue Transmission Risk

click on the image to enlarge

For additional information on dengue, 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 is transmitted by the Aedes aegypti mosquito - a day-time biter with peak periods of biting activity during the morning for several hours after sunrise and in the late afternoon for several hours before sunset. However, the mosquito may feed at any time during the day, especially indoors, in shady areas, or when it is overcast. Aedes aegypti mosquitoes are most often found in or near human dwellings in urban areas.

The Public Health Agency of Canada recommends that travellers to areas where dengue is known to occur (Figure 1) take the following personal protective measures to prevent mosquito bites.  Personal protective measures include:

• apply a DEET-based insect repellent to exposed skin;
• when possible, remain in well-screened or completely enclosed, air-conditioned areas during peak biting times; and
• wear light-coloured clothing with full-length pant legs and sleeves;

Comprehensive information on mosquito-bite avoidance is detailed in the Committee to Advise on Tropical Medicine and Travel's “Statement on Personal Protective Measures to Prevent Arthropod Bites".

NOTE: If a fever develops within two weeks of leaving a dengue-endemic area, see a physician and indicate that you have recently travelled to a tropical region. 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.

As a reminder…

The Public Health Agency of Canada routinely recommends that Canadian travellers consult their personal physician or a travel clinic six to eight 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.

Additional information:

• For more information on dengue fever, visit the Public Health Agency of Canada's Disease Information Backgrounder on dengue fever
• For additional information on dengue fever activity in the Americas, visit the Pan American Health Organization's Dengue Feverpage
• 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.