If you are planning to travel abroad during the Chuseok holiday, it would be wise to pack mosquito repellent first. Dengue fever, a mosquito-borne infectious disease, is spreading rapidly this year in popular destinations across Southeast and South Asia.
According to data recently compiled by Outbreak News Today based on public health authorities in each country, dengue cases in major Southeast and South Asian nations have risen noticeably compared with last year. Cambodia recorded 54,697 infections as of early August, up 81% from 30,200 in the same period last year. Malaysia saw 42,848 cases, a 35% increase, while deaths jumped 79% from 19 to 34. Vietnam reported 73,828 infections through July, 1.3 times more than a year earlier.
The situation is similar in South Asia. Sri Lanka has recorded 95,035 infections this year and 72 deaths, while Bangladesh has recently seen nearly 1,100 new cases in a single day. In Afghanistan, suspected cases in July rose 85% from the previous month. These are all regions frequently visited by Korean travelers.
◆ What is dengue fever?
Dengue fever is an acute febrile illness caused by being bitten by mosquitoes infected with the dengue virus. It does not spread directly from person to person; rather, it is transmitted when mosquitoes carrying the virus, such as Aedes aegypti and Aedes albopictus, bite humans. Unlike malaria mosquitoes, these mosquitoes are active mainly during the day, especially in the early morning and around sunset.
Four to seven days after being bitten, symptoms such as sudden high fever, severe headache, pain behind the eyes, muscle and joint pain, and a rash may appear. Most patients recover within one to two weeks without special treatment. However, in rare cases, the disease can worsen into severe dengue accompanied by bleeding or a drop in blood pressure, which can be life-threatening. The risk of severe illness is especially higher if a person who has already had dengue is reinfected with a different type of the virus.
The problem is that there is no effective weapon. There is no commercially available dengue vaccine in Korea, and there is no specific antiviral treatment that directly eliminates the virus. Only symptomatic treatment, such as reducing fever and providing fluids, is possible. In the end, avoiding mosquito bites is the most reliable prevention method.
◆ Choose mosquito repellent based on ingredients
The key to prevention is avoiding mosquito bites, but there are also practical tips. People often hear advice such as wearing long sleeves and applying repellent, but not as much is known about which repellents to use or how often to apply them.
The duration of a repellent depends on its ingredients. According to travel medicine information, products containing 20% picaridin work for about 8 to 10 hours, 20% to 30% DEET products for about 5 to 6 hours, and plant-based citron eucalyptus oil for about 4 to 6 hours. Low-concentration products with around 7% DEET, often sold in hotel souvenir shops, do not last long enough for dengue-endemic areas. The concentration should be chosen based on the length of travel and the amount of outdoor activity.
Clothing requires a different approach. Unlike skin repellent, permethrin is an insecticidal ingredient sprayed on clothes; when mosquitoes touch treated fabric, they are repelled and killed. If applied to clothing in advance and allowed to dry before travel, its effect can last for about six washes. It is especially useful to treat sleeves, pant cuffs, and particularly the ankles, where dengue mosquitoes like to bite.
There is also a proper order for application. When using sunscreen and insect repellent together, sunscreen should be applied first, allowed to absorb for 15 to 20 minutes, and then repellent should be applied on top. Products that combine both ingredients are not recommended. Sunscreen must be reapplied every two hours, but repellent does not, so using a combined product can result in excessive application of repellent ingredients.
Pregnant women and children require extra caution. For pregnant women, using repellent is better as long as the instructions are followed, since the risks of Zika and malaria are greater. For infants under two months old, chemical repellents should be avoided in favor of fine mosquito nets. When applying repellent to children, an adult should first place it on their own hands and then apply it to the child’s skin. Wristband-type products, ultrasonic repellents, and citronella candles have not been proven effective in field tests.
◆ Three prevention rules to follow at your destination
The prevention methods recommended by health authorities are simple. First, reduce exposed skin by wearing long sleeves and long pants even during the day. Light-colored clothing attracts fewer mosquitoes. Second, apply mosquito repellent to exposed skin and clothing. Check the ingredients and instructions, and reapply at the proper intervals to maintain effectiveness. Third, choose accommodations with window screens and air conditioning, and use a mosquito net when sleeping.
When spending time outdoors, it is best to avoid areas near standing water where mosquitoes lay eggs. Puddles, plant saucers, and water collected in discarded containers can become mosquito breeding grounds. It is safer to reduce outdoor activities during early morning and around sunset, when mosquitoes are most active.
Care after returning home is also important. Because dengue has an incubation period, symptoms often appear after returning home rather than during the trip. If you develop a sudden fever within two weeks of returning from travel, do not dismiss it as a common cold; visit a hospital and inform medical staff of your overseas travel. The earlier it is diagnosed, the lower the risk of progression to severe illness.
During the excitement of the holiday, it is easy to put health last. Yet simply packing mosquito repellent and long-sleeved clothing, and monitoring your condition for a few days after returning, can help preserve the happy ending to your trip.
