Keeping Mosquitoes Away

Sometimes our mothers know things that later proved to be with scientific basis. This is one of those things.

SINCE I was a kid, there was a question to which I did not find an answer. That is, until lately. So many years hence! And the question is: Why is it that in the evening mosquitoes tend to hover on certain persons’ head, and not on others?

I asked my mother about this, and her reply was: “That will happen to children who have not taken a bath for a day.”

I thought of that answer more as a persuasion to not resist taking a bath each day in the morning. But then after reading a research report published in PLoS One in December 2010, I have to admit that her answer makes scientific sense. Bacteria are instrumental in the production of human body odors. Newly secreted sweat is odorless.

But the presence of bacteria on the human skin results in the formation of volatile acids with distinct, and oftentimes unique, smell. Have you ever wondered why no two persons smell much like the other (minus the splashed scents)?

In fact, last year scientists discovered that each person has a unique composition of living microorganisms on their skin. So unique indeed that the Fierer Study, published in the Proceedings of the National Academy of Science USA, proposed that this be used as a forensic tool in identifying suspects in criminal investigation.

Way back in 1980, scientists had already verified that carbon dioxide has a role in attracting mosquitoes over long distances. In 2009, the Smallegange study successfully identified a basic blend of compounds on the skin that consistently attract mosquitoes towards it. These compounds include ammonia, lactic acid and tetradecanoic acid.

Subsequently, on Dec. 30, 2009, Niels Verhulst and colleagues from the Laboratory of Entomology of Wageningen University and Research Centre in The Netherlands identified more bacteria-generated volatile acids that effectively attract mosquitoes to attack the human skin. These compounds include... [Read more.]

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