The Scientific Reasons Why You Get So Many Mosquito Bites

I love the warmth and constant sunshine that come with North Carolina summers. This time of year allows me to spend more time outside doing the things I enjoy: hiking, biking, walking my dog, and spending time at the beach. But that time in nature is quickly ruined when I find myself covered in red, itchy bumps after just a few minutes outside. Mosquito season starts in March and can last into November in some states. That means it’s still peak mosquito season.

If you are like me, you get frustrated with the number of mosquito bites you get. It is downright frustrating when I come in with multiple new bumps, while my friends say they have none.

Why is that? It’s not that I’m particularly unhappy. There are actually scientific reasons why mosquitoes pick on certain people. Here’s why mosquitoes bite and how to make yourself less of a target this summer. For more information, read How to Safely Remove a Tick and How to Change the Colors of Your Hydrangeas.

Why do mosquitoes bite?

Contrary to what you might think, mosquitoes don’t bite people for food; they feed on plant nectar. Only female mosquitoes bite, and they do it for receive proteins from your blood, which is necessary for their eggs to develop.

Why are some people more sensitive to bites?

There are several factors that make some people more susceptible to mosquito bites than others:

Blood group

A common belief is that mosquitoes are attracted to certain blood groupssince mosquitoes bite humans for their blood. Blood type is determined by genetics, and each blood type is created based on the different sets of specific proteins, called antigens, on the surface of red blood cells. There are four main blood types: A, B, AB, and O.

Although there are no definitive conclusions about which blood type is more attractive to mosquitoes, several studies have suggested that people with blood type O are the most attractive to mosquitoes. Study 2019 observed the feeding behavior of mosquitoes when presented with different blood type samples, and found that mosquitoes ate more from the type O feeder than from any other feeder. Study from 2004 also found that mosquitoes land significantly more often on blood group O secretors (83.3%) than on group A secretors (46.5%).

However, these studies are not conclusive and much remains unclear about mosquitoes’ blood group preferences.

Clothing color

Mosquitoes are very visual hunters when it comes to finding a human to bite. This means that movement and dark clothing colors such as black, navy and red will stand out to a mosquito. Research has shown that mosquitoes are more attracted to the color black, but little additional research has been done into the reason for this.

Carbon dioxide

Mosquitoes use sight and smell to find hosts to bite. One of the fastest ways mosquitoes can track down a person is through the carbon dioxide that is released when we breathe. According to research published in the journal Chemical sensesMosquitoes use an organ called the maxillary palp to detect carbon dioxide and can detect it from a distance of 50 meters.

Because carbon dioxide has a strong attraction, people who emit more carbon dioxide (larger people and people who breathe heavily during exercise) become more attractive to mosquitoes.

Body odor and sweat

Mosquitoes are attracted to more substances and compounds than just carbon dioxide. Mosquitoes can find people to bite by smelling substances present on human skin and in sweat, including lactic acid, uric acid, and ammonia.

A new study discovered that mosquitoes are attracted to compounds called carboxylic acids that every human produces via sebum, a waxy layer on their skin. The sebum is eaten by the millions of beneficial microorganisms found on human skin, which produce more carboxylic acid — in turn producing an odor similar to cheese or stinky feet that seems to attract mosquitoes. The lead researchers of this study said Mosquitoes are sensitive to human odors and even perfumes or colognes cannot mask them.

Researchers are still trying to figure out why certain body odors are more attractive to mosquitoes, but they do know that genetics, bacteria on the skin, and exercise all play a role. Genetics affect the amount of uric acid excreted, while exercise increases the buildup of lactic acid.

Beer

In a small studyMosquitoes were more likely to land on participants after consuming a small amount of beer. But before you swear off outdoor beers, know that the study only had 14 participants and found that mosquitoes may be only marginally more attracted to people who had been drinking beer.

Why do some people swell more from mosquito bites than others?

Mosquito bites can range in size from small spots to large welts. Why is this the case?

Bites affect people in different ways. The size and severity of a bite depends on how your immune system responds to the saliva that the mosquito puts in when it bites. When mosquitoes bite, they inject some saliva when they draw blood. This saliva contains certain anticoagulants and proteins, which cause the immune system to respond to these foreign substances.

Our body responds by releasing histamine, a chemical released by white blood cells when your immune system is fighting allergens. This causes the bite to itch and become inflamed.

How do you prevent mosquito bites?

The best way to treat a mosquito bite is to avoid getting bitten in the first place. But often that’s easier said than done.

Some common ways to prevent mosquito bites include:

• Use insect repellents and insect sprays (Repel, Off Deep Woods and other brands containing DEET)
• Use natural repellents (citronella) essential oilneem oil, thyme essential oil)
• Avoid going outside at sunrise or sunset
• Avoid dark clothing, especially black
• Avoid standing water and try to eliminate standing water near your home
• Use a mosquito net when camping or sleeping outdoors
• Wear long sleeves and long pants
• Prevent mosquito bites while traveling international

When using insect repellent containing DEET, be sure to follow these instructions: Guidelines from the Centers for Disease Control and Prevention (PDF) on strength and correct application.

How to Treat Mosquito Bites

Mosquito bites are annoying, but often not serious and disappear within a few days. In the meantime, there are several treatments to relieve the itching and inflammation:

• Clean a fresh bite with rubbing alcohol
• Take an oatmeal bath
• Use over-the-counter antihistamines such as Benadryl or Claritin
  
• Apply mild corticosteroid creams
  
• Use aloe vera to reduce inflammation
• Try a cold compress or ice pack for 10 minutes

Although it may be uncomfortable, try not to scratch the bite too roughly to avoid skin reactions or infection.

Mosquito-borne diseases and conditions

Although most mosquito bites cause bumps that heal within a few days, mosquitoes are known to transmit many deadly diseases and conditions, including (but not limited to):

Mosquitoes are often considered one of the deadliest animals on Earth. Mosquito-borne diseases kill more than 725,000 people each year, the World Health Organization estimateswith malaria being the cause of the vast majority of deaths (600,000).

Although malaria and other mosquito-borne diseases hit sub-Saharan Africa the hardest, mosquitoes pose a risk to every continent and country. Most mosquito species in the U.S. are nuisance mosquitoes — mosquitoes that don’t spread germs that make people sick — but there are outbreaks of West Nile, dengue, chikungunya and Zika in some states and territories.

There are several steps you can take to keep mosquito populations under control and minimize the risk. Make sure to properly cover and store water containers around your home and drain any standing water to prevent mosquitoes from laying eggs. For treatments, you can use a outside adult killer to kill adult mosquitoes or larvicides for the treatment of stagnant water that is not used as drinking water and cannot be drained away.

Infected bites often appear extremely red, swollen, and warm, or have a red streak extending outward from the bite. See a health care professional if you have signs of infection or if symptoms worsen.

For more information about the Five Smart Ways to Repel Mosquitoes this summer, the mosquito forecast tool launched by Google and Off, and how you can do it make your own diy traps against mosquitoes, horseflies and other flying pests.

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