The return of summer means mosquitoes! Every year, these pests enter our homes, preventing us from enjoying evenings outdoors. And this year, even more than usual, since there wasn't really any winter, and quite a lot of rain in the spring. Why are some people stung more often than others, and how can they protect themselves? We take a look.
The answer lies in the composition of the bacteria on our skin, the molecules they produce and the amount of CO2 emitted when we breathe. The CO2 we emit when we breathe attracts mosquitoes. Anna-Bella Failloux, an entomologist at the Pasteur Institute, explains to BFMTV that mosquitoes are particularly sensitive to this gas. In addition to CO2, our skin microbiota plays a crucial role. Composed mainly of bacteria, it releases molecules such as lactic acid and ammonia, which also attract mosquitoes. The density and composition of these molecules vary according to genetics, state of health, diet and physical activity. It is therefore important, even crucial, to shower after a sports session or exercise, and all without perfume afterwards.
Soaps can influence mosquito attractiveness by altering host selection. An American study from 2023 shows that some soaps increase attractiveness, while others reduce it. This phenomenon depends on the chemical composition of the soap and its interaction with the skin microbiota. According to this study, mosquitoes could be attracted to soaps with floral or fruit scents, since when they're not feeding on blood, they'll seek to supplement their sugar intake in plant nectars. "Spraying us with plant-derived or plant-mimicking scents could therefore potentially disrupt their decision-making," explains the research team in a press release.
In 2004, researchers published a study in the Journal of Medical Entomology revealing that people of blood groups A and O were more likely to be bitten by mosquitoes than those of blood group B. This attraction is due to the secretions produced by these blood groups. This attraction is due to the secretions produced by these blood groups. Group O, in particular, is more attractive to mosquitoes due to its higher concentration of the proteins required for insect reproduction. It's important to remember that only female mosquitoes bite, as they need blood for their eggs to mature.
You've all heard it before, or even said it: "Turn off the light, you'll attract mosquitoes!". Sorry to disappoint you, but turning off the light won't save you from mosquito bites. In fact, some mosquitoes, such as tiger mosquitoes, are not sensitive to light and bite regardless of lighting. Although some species, such as Culex and Anopheles, are attracted to light, it's not their only attraction. They are primarily interested in finding food. Mosquitoes are mainly attracted by CO₂, which they detect at around 50 meters. The more of it a person emits, by breathing or sweating, the more mosquitoes are attracted. Once they detect CO₂, they head for body heat and odor. People who have just worked out, for example, are more likely to be bitten because of their high heart rate and body heat.
For effective protection, mosquito netting remains the best option. It should be installed over openings and around beds. Citronella candles are also useful, but it's mainly the smoke that keeps the mosquitoes away.
Assurance Maladie recommends the use of skin repellents, such as DEET andIR3535, with precautions for pregnant women and young children. Repellents in cream or lotion form are recommended to avoid the risk of inhalation or ingestion.
Wear loose-fitting, light, covering clothing to limit skin exposure. Mosquitoes are attracted to dark colors, so it's best to choose light-colored clothing. It's also crucial to empty or cover containers of stagnant water outdoors, as these are ideal breeding grounds for tiger mosquitoes. Empty bowls, pots, planters, vases and all containers, including those on windowsills, every week. Clean them thoroughly to eliminate larvae. Water sparingly and check gutters. Fans and, even better, air conditioners can also keep out mosquitoes that can't stand the cold.
The tiger mosquito is a particularly invasive insect that settles in our region between May and November. It bites mainly during the day and represents a health risk. In most cases, tiger mosquito bites are harmless and disappear within a few days. However, tiger mosquitoes can transmit potentially serious viral diseases (dengue, chikungunya, zika).
A mosquito bite can provoke a skin reaction in the person bitten. The mosquito's saliva triggers an immune response, causing a local inflammatory reaction. This inflammatory reaction leads to symptoms such as itching, redness and swelling around the bite. When the immune system reacts to the sting, it releases histamine, a substance that causes vasodilation. Vasodilation increases blood flow to the area of the sting, which can lead to irritation and itching sensations.
Even if you take precautions, getting stung is sometimes unavoidable. To relieve a sting, avoid scratching, disinfect and clean the area with soap and water. Apply an ice cube wrapped in a clean cloth to reduce inflammation and itching. Use natural solutions such as baking soda, essential oils (tea tree, lavender) or cider vinegar to soothe the bite. It's important not to scratch a bite, as this can lead to infection. If itching persists, or if signs of infection appear, such as an oozing sore or extensive redness around the bite, consult a doctor.
By following these tips, you can significantly reduce your risk of mosquito bites and enjoy a trouble-free summer.
