Health Tips

You are trying to have a good sleep, but the mosquitoes just would not spare you for even a night. This is indeed a common experience shared by many people residing in Malaysia. Mosquitoes are the bane to our existence because of their annoying bites: often starts with a pierce to the skin, leaving behind an itchy red welt. That is not the worse: In June 2020, Malaysia was projected to record a higher number of dengue cases until September after the disease showed an upward trend of 8 percent for six consecutive weeks. A female mosquito species called Aedes aegypti is responsible for transmitting the dengue virus from human to human. 

What happens when a mosquito bites me?

When a mosquito bites you, it pierces the skin using a special mouthpart (proboscis) to suck up blood. As the mosquito is feeding, it injects saliva into your skin. Your body reacts to the saliva resulting in a bump and itching.

Some people have only a mild reaction to a bite or bites. Other people react more strongly, and a large area of swelling, soreness, and redness can occur.

💡 Fun fact: Do you know that only female mosquitoes bite people and animals to get a blood meal? This is because most female mosquitoes cannot produce eggs without a blood meal. Male mosquitoes do not bite people and animals.

Who mosquitoes like best?

Why do some people attract mosquito bites better than others? It turns out that female mosquitoes can be ‘choosy’ when it comes to the blood meal of the day.

1. Genetics

A study conducted by scientists at Pfizer Inc. and 23andMe found out that there are 15 genetic variants among the 69,000 subjects that are linked to higher perceived attractiveness to mosquitoes as well as greater immune’s response to mosquito bites. The study concluded that when it comes to the relationship between human and mosquito bites, a complex interaction between genetic and immunological factors are in play. 

2. Higher metabolic rate

Female mosquitoes search for their next victim by tracking down the human’s carbon dioxide output, a by-product our body releases as metabolism takes place. Hence, people with higher metabolic rate seem to release higher carbon dioxide, therefore attract more mosquitoes. Nonetheless, as our metabolic rate is largely predetermined by our genetic profile, there is nothing much we can do to significantly alter our metabolism. Avoid carrying out activities that may temporarily raise your metabolism such as drinking alcohol or exercising may help to reduce mosquito bites -- although we don’t necessarily recommend you stop exercising just to prevent mosquito bites, as it can have tremendous health benefits.

3. Pregnant women

Mosquitoes also prefer pregnant women, as pregnant women on average have higher metabolic rates than nonpregnant women. One study found pregnant women exhale 21% more carbon dioxide than their nonpregnant counterparts. Pregnant women also have higher body temperature, another attractor to mosquito bites. 

Prevent mosquito bites

1. Create physical barrier that prevents the mosquitoes from coming to you in the first place

• Wear light-coloured, loose-fitting, long clothing (cotton and linen) as much as possible. 

• Don’t use scented soaps, shampoos, deodorants, perfumes or after-shaves.

• Ensure that all door and window screens do not have tears or holes and that they are tightly fitted.

• Cover any food, drinks, compost and garbage.

• Always wear shoes, both indoors and outdoors.

• Sleep or rest under an insecticide-treated bed net.

2. Use mosquito repellent or insecticide

• Use a spray, lotion, towelette, or liquid repellent containing 20-30% DEET or 20% Picaridin on exposed skin. Apply according to manufacturer’s directions to ensure optimal protection. Re-apply on shorter times if you find that you are starting to get bitten. Note that repellents destroy items containing crystal or plastics so be careful if you wear jewellery or glass.

• When using repellents on children, check the manufacturer’s directions. Talk to your doctor about using a repellent if you’re travelling with an infant to an area with high risk of mosquito-transmitted illnesses. To further protect your child, ensure that they wear long light-coloured, loose-fitting clothing, cover their carrier with tight-fitting mosquito netting or place them under an insecticide-treated net when playing or resting.

• If you are wearing sunscreen, apply sunscreen first and repellent second. Allow the sunscreen to penetrate the skin for 20 minutes before using repellent. Note that this could reduce the efficacy of the sunscreen, so it’s best to reapply often or wear long clothing.

References:

1. https://www.webmd.com/allergies/features/are-you-mosquito-magnet#1

2. https://www.cdc.gov/mosquitoes/mosquito-bites/symptoms.html

3. https://www.iamat.org/country/malaysia/insect-bite-prevention

Written by

Ms Joyce Toh