CDC / William Collins / DAPD
A mosquito of the genus Anopheles in blood eyes on the bacteria that counts
If you awakened at night by a nasty, high-pitched buzz, it is often too late: The mosquito has stabbed himself, and incorporated their blood meal. And while you are scraping the itchy bites the next day, the partner smiles gleefully because the mosquito has spurned his blood.
But why mosquitoes like the blood of some people more, the other less? The tale of sweet blood will not get us. The reason can be found elsewhere: on the human skin, now an entomologist Niels Verhulst of the Dutch University of Wageningen write in the journal “PLoS One” .
Accordingly, the composition determines the bacteria on the skin, which people are more attractive to mosquitoes. This context, the researchers found at least in Anopheles gambiae mosquitoes of the species whose bites are particularly dangerous because they can transmit the dangerous malaria parasite.
In the service of research 48 male subjects had voluntarily let themselves suck. In order to avoid influences by other factors, smell, the participants were allowed to briefly before the experiment, no alcohol or garlic or other spicy foods drink eat, shower, or do not use perfumed cosmetics. In addition, the researchers analyzed the so-called skin microbiome of the subjects. This means the genetic material of all living organisms on the skin.
It all depends on the mixture
Without bacteria, the human sweat would smell, because every micro-organism converts the various substances in the liquid. The resulting metabolites are volatile and care for each person for a unique body odor. As the mosquito bite test resulted in the volunteers, nine of the 48 subjects were pestered by mosquitoes remarkably happy. Seven were among the mosquitoes, however less popular. All other subjects were often engraved on average.
The comparison of the microbiome of the different test subjects showed that the smaller was the number of different types of bacteria on the skin of humans and the more bacteria in total were on her, the more popular was the test subject for the mosquitoes.
In addition, there were obviously particular type of bacteria, Staphylococcus epidermidis, which provided for increased attractiveness. Their metabolic products, the researchers suspect the smell, the flies very well. Other hand, produce the kind of bacteria Pseudomonas aeruginosa discourage rather fragrances, the mosquitoes. Both types are represented in the bacteria cocktail on the human skin. It would, therefore, important to write Verhulst and his colleagues, how often they were in relation to other types of bacteria present.
The researchers hope now is to be able to produce with the help of the results of a day tailor-made insect repellent. This could also contribute to the transmission of malaria control purposes.