Buggers, bloodsuckers, whatever you call them, the mozzies are back with a vengeance. From the start of this year, the Aedes mosquitoes have spread dengue fever to more than 7000 people in Singapore, and the numbers are still rising with the recent temperature spike. If like me, you’re kind of like the fine dining establishment for the bugs – attracting swarms from far and wide for a scratchy blood feast, while others around you remain untouched – news of the worst dengue epidemic in 5 years isn’t going to go down well.
ARE YOU OOZING ANIMAL APPEAL?
Scientists are starting to unravel the skin-piercing mystery of this ‘animal attraction’, and hopefully find new solutions to cover us where current repellents have failed. Mosquitoes fly through an aerial soup of chemicals, but can home in on a yummy blend of ‘Eau de Mozzie’ that cues them in on their perfect human blood meal from an impressive distance of 50 metres. In case you’re wondering, it’s got nothing to do with your blood sugar levels (sweet blood) or the Chanel No. 5 you’re wearing.
Carbon dioxide is one of the magical compounds that increases your attractiveness to mosquitoes. Larger people tend to give off more carbon dioxide, which is the reason why the pests prefer to munch on adults to tods (although kiddos tend to have worse and more swollen insect bite reactions in their skin). Pregnant women are also at increased risk, as mothers-to-be exhale 21 percent more carbon dioxide. If you’d like to reduce your chances of being the target of a sketter aerial attack at your next outdoor gathering, stake out at the chaise lounge rather than a spot in the frisbee game – the scent of carbon dioxide as you pant, in addition to all the movement and heat, will draw the pesky enemies in. Moreover, lactic acid released in the sweat is a turn-on for these bloodthirsty predators too.
Gulping down 12 ounces of beer at the evening poolside grill seem to amp up your mosquito appeal as well, possibly due to the increase in body temperature it causes, or because of a change in odorous skin markers when metabolising the alcohol. Those with type ‘O’ blood are not only the universal donor for human blood banks, their life juice appears to be a hot commodity amongst some species of mozzies too, as a result of the blood type markers secreted through their skin.
Like man-repelling BO, certain chemicals produced by the body when we are under stress appear to be a turn-off for the buggers. Scientists postulate that mosquitoes may deem hosts that emit more of these chemicals to be ‘diseased’ and hence, not a good quality blood meal. Proteins in the blood are necessary for female mosquitoes to produce fertile eggs, and it might be evolutionarily advantageous for the shrewd stingers to detect and avoid such people.
By either masking the vulnerable individual’s scent signature with more effective and environmentally safe natural chemicals, or disarming the mosquitoes’ ability to detect carbon dioxide emissions, or by luring elusive swarms into traps with non-toxic attractants, researchers and infectious disease experts are anxiously scratching their heads to find a practical solution to replace the current chemical repellents and pesticides by solving the mozzie preference puzzle.
Meanwhile, there are 3 commonly used repellents proven to keep the bites at bay when you suspect you may be under siege:
If you’re going out to enjoy the insect-swarmed great outdoors this summer holiday, you might want to consider applying permithrin (an insecticide and repellent) on your clothes and fabric-covered equipment. Cover yourself up with long sleeves, long pants and wide-brim hats (it protects your ears and nape from the bugs and UV); and choose light-coloured clothing. Unfortunately, anecdotal wisdom like popping vitamin B (thiamine) supplements or garlic pills are not backed by solid scientific evidence to work as repellents for natural human bug baits.
CAUTION: Just because you don’t tend to break out in itchy welts that make mozzie attacks annoyingly noticeable, it doesn’t mean you are a natural bug repellant and safe from dengue fever. These city-trained stealth fliers can produce painless and even non-itchy bites, which means you might not even realise you’ve been bitten till symptoms of the dengue infection surface. So whether for your own health or for the safety of your loved ones, do your part to keep your space skeeter unfriendly and take the necessary precautions during the current dengue epidemic.
– By Michelle Wenli