What is it that makes some people so attractive to mosquitoes, while others are left alone? The cause appears to be linked to the amount of carbon dioxide we exhale and to our body odour. A group of researchers at Wageningen University in the Netherlands demonstrated that our skin microbiota determines how attractive a person is to mosquitoes
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It is often claimed that some people have “tastier” or “sweeter” blood than others. However, scientific research shows this is not the case at all. The cause appears to be linked to the amount of carbon dioxide we exhale and to our body odour. Female mosquitoes (the ones that bite) are attracted by carbon dioxide. They have a special organ that can detect carbon dioxide at distances of up to 50 metres. This is one of the reasons why pregnant women are more likely to get bitten by mosquitoes. A study published in The Lancet in 2002 showed that pregnant women in their final trimester exhale 21 percent more carbon dioxide than non-pregnant women. And that is why mosquitoes prefer adults over children, although it may seem that children are bitten more frequently. Because the body gradually gets used to the components in mosquito saliva, adults get fewer and smaller bumps that often recede much faster.
Skin microbiota
In addition to carbon dioxide, mosquitoes are also attracted by our scent, both in our breath and our perspiration. How does this work? Our skin microbiota plays a major role in this. Our scent comprises roughly 300 different components, which are the product of the breakdown of our sweat by the skin microbiota. A group of researchers at Wageningen University in the Netherlands demonstrated that our skin microbiota determines how attractive a person is to mosquitoes. They asked 48 male volunteers to avoid alcohol, garlic, onions and spicy foods for two days, and to use only unscented personal care products during that time. They were also asked to wear nylon socks for 24 hours. After that, glass beads were rubbed on the soles of their feet to collect their scent. These were presented to the mosquitoes. The results were fascinating: The sweat of nine of the men appeared to be particularly attractive to the mosquitoes, while the sweat of seven other men was completely ignored.
When the composition of their microbiota was examined, microbes in the “highly attractive” group were shown to be less diverse and more numerous. Also, the presence of Staphylococcus species was shown to be associated with attractive individuals (attractive to the mosquitoes, that is), while Pseudomonas species were associated with less attractive individuals.
By trying to find out as much as possible about the scents favoured by mosquitoes over others, researchers hope to be able to devise a “scent trap” for malaria mosquitoes.
