The perpetually wet and warm climate in Southeast Asia ensures that there is never a shortage of mosquitoes. Ranging from covert ankle-biters to ridiculously sized creatures fit for a horror movie, mozzies - as the Australians affectionately call them - are always looking for a free meal.
Aside from being a nuisance while traveling in Southeast Asia, mosquitoes pose two real threats: disease and infection. Scratching mosquito bites with dirty fingernails in a tropical environment can quickly turn a tiny problem into a fever-causing infection. Oozing mosquito bites on legs are a common site found on backpackers in Southeast Asia.
While mosquitoes will probably prove to be only a slight nuisance during your trip to Southeast Asia, the tiny insects are far more nefarious than snakes or any other creature encountered in the wild.
The World Health Organization estimates that approximately 20,000 people die per year due to snakebite, but malaria - delivered by mosquitoes - kills more than fifty times that number of people annually. Factor in other mosquito-borne illnesses - among them dengue and the shadowy Zika virus - and suddenly humans appear to be losing the battle.
Why do Mosquitoes Bite?
Despite their size, mosquitoes are actually the deadliest creatures on Earth; scores of studies have taken place for determining how to prevent mosquito bites. Both male and female mosquitoes prefer to feed on flower nectar; however, females switch to an all-protein diet of blood when they are ready to reproduce. Strangely, studies show that mosquitoes prefer to bite men over women; overweight people are at greater risk.
Mosquitoes can hone in on carbon dioxide emitted from breath and skin from over 75 feet away. While hiding or holding your breath is not practical, taking proper measures can decrease your risk for bites.
Mosquitoes and Dengue Fever
While malaria receives most of the spotlight, the World Health Organization estimates that mosquitoes cause at least 50 million cases of dengue fever each year. Before 1970 only an estimated nine countries held a risk for Dengue Fever. Now dengue fever is endemic in 100 countries; Southeast Asia is considered the region with the highest risk.
Unfortunately there is no vaccination or preventative for dengue fever other than to avoid being bitten in the first place.
The spotted mosquitoes that carry dengue fever typically bite during the day, while the species that carries malaria prefers to bite at night. Chances are high that you would survive an infection, but dengue fever will certainly ruin an otherwise fantastic trip!
Mosquitoes and Zika Virus
The same Aedes aegypti mosquito that spreads yellow fever and dengue can also give unsuspecting visitors a dose of the Zika virus.
Southeast Asia happens to be one of the Zika virus's top hotspots, though it hardly counts as an “epidemic” yet: the worst-hit country, Thailand, only reported seven cases between 2012 and 2014, with Cambodia, Indonesia, Malaysia and the Philippines only reporting a single case of Zika virus each since 2010. (Source)
Some suspect that Zika cases are underreported in Southeast Asia, given its usually mild appearance and similarity in symptoms with other viral infections like chikugunya and dengue. A few patients develop temporary paralysis after exposure, but Zika virus reserves its worst for women who get infected while pregnant; their babies have an increased likelihood of developing microcephaly.
Ten Tips for Preventing Mosquito Bites
- You are most at risk for mosquito bites - particularly in the islands - as the sun lowers; use extra caution at dusk.
- Pay attention under the tables when eating in Southeast Asia. Mosquitoes would love to enjoy you as a meal while you eat your own.
- Wear earth tones, khaki, or neutral clothing while trekking. Studies show that mosquitoes are more attracted to bright clothing.
- If staying in a place with a mosquito net, use it! Check for holes and apply DEET to any breeches. Do the same for any broken window screens around your accommodation.
- Mosquitoes are attracted to body odor and sweat; stay clean to avoid attracting unnecessary attention from mosquitoes and clean travel mates.
- Female mosquitoes normally feed on flower nectar when not trying to reproduce - avoid smelling like one! Sweet-smelling fragrances in soap, shampoo, and lotion will attract more biters.
- Unfortunately, DEET remains the most effective known way to prevent mosquito bites. Reapply smaller concentrations of DEET every three hours to exposed skin.
- Although the hot climate usually dictates otherwise, the most natural way to prevent mosquito bites is to expose as little skin as possible.
- Gecko lizards, considered lucky in Southeast Asia, eat several mosquitoes a minute. If you are lucky enough to have one of these little friends in your room, let her stay!
- Make a habit of closing your bathroom door after checking in to your accommodation; even small amounts of standing water give mosquitoes a better chance.
DEET - Safe or Toxic?
Developed by the U.S. Army, DEET is the most popular way to control mosquitoes despite the ill effects on skin and health. Concentrations up to 100% DEET can be purchased in the U.S., however Canada barred sales of any repellent containing more than 30% DEET due to its high toxicity.
Contrary to folklore, higher concentrations of DEET are no more effective for preventing mosquito bites than lower concentrations. The difference is that higher DEET concentrations are effective longer between applications. The Centers for Disease Control and Prevention recommends that a solution of 30 - 50% DEET be reapplied every three hours for maximum safety.
When used in conjunction with sunscreen, DEET should always be applied to skin first before sun protection. DEET lowers the effectiveness of sunscreen; avoid products that combine both. Read more about how to avoid sunburn in Southeast Asia.
Do not apply DEET under your clothes or on your hands, inevitably you will forget and end up rubbing your eyes or mouth!
- Make sure your luggage contains only useful stuff: What to Pack for your Trip to Southeast Asia.
DEET Alternatives for Preventing Mosquito Bites
- Icaridin: Also called Picaridin, the World Health Organization promotes the use of icaridin as a DEET alternative. The repellent is odorless and causes less skin irritations than DEET. Even the Australian army has adopted its use in the field.
- Lemon Eucalyptus Oil: Oil from the lemon eucalyptus is considered a safe, natural alternative to DEET, although it is less effective and liberal doses must be used.
- Skin-So-Soft: Avon Skin-So-Soft contains an agent known as IR3535 which is effective for repelling mosquitoes for short durations.
A cheap, popular way to prevent mosquito bites in Southeast Asia is to burn mosquito coils under your table or while sitting outside. Coils are made from pyrethrum, a powder derived from chrysanthemum plants, and burn slowly to provide protection for hours; never burn mosquito coils inside!
Mosquitoes and Electric Fans
Electric fans are a low-tech anti-mosquito solution, found practically everywhere. Fans disrupt mosquito attacks in two ways: first, the weak-winged mosquitoes find it very difficult to navigate in the wake of a fan running even at low power; second, the winds disperse the carbon dioxide trail we emit that mosquitoes zero in on when looking for a meal.
So when not on the road, find a resting spot in the direct line of fire of a working electric fan. Feel free to sleep with an electric fan pointed straight at you (no matter what your Korean friends might say - read more about the interesting Korean cultural myth of "fan deaths".)