Some people are bitten by mosquitoes more often
One wakes up with innumerable mosquito bites, the other does not have a bite. In the vernacular, the motto is: "mosquitoes bite especially those who have sweet blood". But what is it about the myth? James Logan of the London School of Hygiene and Tropical Medicine answered this question in a study with his team.
The scientists report that mosquitoes are not attracted by the “sweet blood” but by the body scent of humans. However, this finding is not new. So far, however, it was unknown that some people are bitten by mosquitoes more than others. With the help of an experimental setup with twin pairs, the researchers investigated the behavior of the mosquitoes. 18 identical male and 19 dizygotic, mostly female, pairs of twins took part in the study. Twins have largely identical genetic structures. The subjects had an age range between 50 and 90 years.
Y containers smeared the mosquitoes directly on the hands
The participants had to be exposed to the mosquito attacks. For this purpose, the lancing animals were channeled through a special flight channel, which split up like a "Y" into two ways after a short distance. The mosquitoes then arrived at the hands of the participants. At the end of the flight channel, the mosquitoes could decide which hand they prefer to bite. The smell was crucial here. Only female yellow fever mosquitoes (Aedes aegypti) that were between 5 and 7 days old were used for the experiment. There were always 20 mosquitoes flying through the tube. The Y-shaped tube was also an odor meter (olfactometer).
Before the experiment, the subjects were instructed not to eat alcohol or other strong-smelling foods such as garlic, cabbage or chilli.
Genetic differences caused more mosquito bites
The result showed that there were almost no differences between the identical twins. The siblings were approximately equally popular or unpopular with the mosquitoes. The results looked completely different for the dizygotic twins, which have genetic differences. "One of the two was much more popular than the other," the scientists write in the study report. The genetic peculiarities are to be found in a further work.
New approach in the fight against malaria and dengue fever
However, the scientists do not want to design a new mosquito repellent commercially, but rather find a way to protect people from the transmission of dangerous infectious diseases such as malaria or dengue fever in the future. "Every year, over a million people die from the consequences of transmitted diseases," says James Logan. "If we understand the genetic basis for variation between individuals, it may be possible to develop tailor-made means for better mosquito control and new defense mechanisms," continued Logan. This approach could lead to "better protection against diseases transmitted by the biting insects". According to the study, home remedies for mosquitoes such as garlic or beer should not prevent the mosquitoes from biting. (sb)