Why Do Some People Always Get Bitten By Mosquitoes While Others Don't?

Have you ever felt like you're being specifically targetted by mosquitoes when you end up with itchy welts all over your body, while your friends seem like they're not even aware of the pesky biters' existence?

So why are some people more susceptible to mosquito bites than others? See if you tick off any of these boxes:

1. You have Type O blood

Some blood types are indeed sweeter than others, metaphorically speaking. A study found that people with Type O blood are 83% more likely to get bitten. People with Type A blood are least likely to become mosquito prey, while those with Type B blood are kind of in the middle.

In addition, 85% of people produce a secretion that signals their blood type, making them more obvious prey for mosquitoes compared to the non-secretors, regardless of blood type.

2. You have a large body size

This has to do with your metabolic rate, or the amount of carbon dioxide (CO2) released from your body as it burns energy. Mosquitoes use CO2 as their primary means of identifying targets and can actually sense CO2 from up to 50 metres away!

Larger people tend to exhale more and give off more carbon dioxide, which is why mosquitoes prefer to go for adults over children. Men are also more likely to be bitten by mosquitoes compared to women, as well as obese or overweight people due to their larger body size and relative heat.

3. You're pregnant

According to a study done in Africa, pregnant women are twice as likely to attract mosquitoes compared to their non-pregnant peers because they give off a greater amount of CO2. In fact, a 2002 study found that women in the later stages of pregnancy exhale 21% more CO2 than non-pregnant women, making them even more noticeable to the pests.

4. You've been exercising or exerting yourself physically

Mosquitoes are attracted to lactic acid, a compound produced by the body after working up a sweat, hence you're more likely to get bitten by mosquitoes if you've just gone out for a run or finished a workout at the gym.

Besides that, the body also experiences a heat increase because of a raise in your body's metabolic rate after strenuous activity or vigorous exercise. Warmth becomes more attractive to mosquitoes as they approach a potential victim.

5. You've just had a beer or a glass of wine

Drinking alcohol also raises your metabolic rate and your body temperature, making you very appealing to mosquitoes.

6. You're wearing red or dark-coloured clothing

Apart from smell, mosquitoes also rely on sight to spot their prey. Red makes you a prime target, as well as dark colours such as black and blue.

Dr. Jonathan Day, a medical entomologist and mosquito expert at the University of Florida, explained, "Mosquitoes have problems flying in even a slight wind, and so they keep close to the ground. Down there, they spot hosts by comparing your silhouette to the horizon. Dark colours stand out, while light shades blend in."

7. Certain elements of your body chemistry are actually calling out to the mosquitoes

People who produce excess amount of certain acids (e.g. lactic acid, uric acid) and/or have higher concentrations of steroids and cholesterol on their skin surface tend to attract mosquitoes. This does not necessarily mean that mosquitoes prey on those with high cholesterol. Rather, these people naturally metabolise and process cholesterol faster than others, the byproducts of which remain on the skin's surface.

On the other hand, a study done by the London School of Hygiene & Tropical Medicine found that people who are bitten less frequently seem to "smell differently to mosquitoes", 

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