(Acknowledgement: Pest Control Advisory Section, Food and Environmental Hygiene Department)
What is Dengue fever?
Dengue Fever is an acute viral disease characterized by sudden onset of fever, severe headache, pain behind the eyes, joint and muscle pain, loss of appetite, nausea and rash. Some infected people may not develop apparent symptoms, and some may only have mild symptoms like fever, e.g. young children may exhibit a milder non-specific febrile illness with rash. The incubation period is 3 to 14 days. Occasionally, the disease may progress to Dengue Heamorrhagic Fever (DHF) with bleeding and shock, leading to death.
Dengue is found in tropical and sub-tropical regions worldwide, and is an endemic disease in many Southeast Asian countries including Singapore, Malaysia, Indonesia, Laos, Thailand, Cambodia, Vietnam and the Philippines. Travellers visiting these places are advised to protect themselves against mosquitoes.
How does it spread?
Dengue virus is transmitted to human by Aedes mosquitoes. This is a day-biting species with increased biting activities for 2 hours after sunrise and several hours before sunset. When a patient suffering from dengue fever is bitten by a vector mosquito, the mosquito is infected and it may spread the disease by biting other people. It cannot be directly transmitted from person to person.
How can you prevent it?
At present, dengue vaccine is not registered in Hong Kong, so travellers must rely on preventing mosquito bites to combat infection. The personal protection measures against mosquito bites are as follows:
- Wear long-sleeved shirts and trousers;
- Rest in air-conditioned or well-screened rooms;
- Use aerosol insecticide indoor and use bed nets if sleeping areas are not air-conditioned or screened.
- Use insect repellents containing DEET on exposed skin and clothings;
- If travelling in endemic rural areas, carry a portable bed net and apply permethrin on it as well as to clothes.
How is it treated?
If falling sick on return to Hong Kong from areas where dengue fever is prevalent, travellers should seek medical advice promptly and inform the doctor of their travel history to facilitate diagnosis. High fever should be treated by sponging and the appropriate use of paracetamol. Do not take aspirin because they can lead to bleeding and cause stomach irritation. There is no specific medication for dengue fever or DHF. Dengue fever is mostly self-limiting. Patients with DHF should be treated promptly with supportive management.
Dengue, countries or areas at risk, 2011
(with permission from the World Health Organization)