Why mosquitoes feast on type O blood and other summer secrets
25 June 2024 15:03
Not everyone suffers equally from mosquitoes in the summer outdoors, in the forest, or by the water. Not everyone is attacked by them with the same persistence. Japanese researchers have discovered who is particularly "favoured" by these insects.
High temperatures, humid air, shaded undergrowth, and proximity to bodies of water are the best environments for pesky mosquitoes - insects from the order Diptera. We often become their "victims" in forests, lakes, or rivers, close to nature, where we seek summer relaxation.
Even equipping yourself with the strongest repellents to ward off intruders does not guarantee protection. Flying "vampires" often seem immune to even the most expensive deterrents.
However, not every evening bonfire or garden gathering participant will be "devoured" equally. After years of research, scientists are confident that our blood types determine mosquitoes' choices, but other factors also play a role.
Why do mosquitoes prefer some people more? Scientists already know
Mosquitoes are not only annoying and leave itchy marks; they are also a threat. As the German magazine Merkury reminds us, some species spread dangerous diseases, such as yellow fever.
The Japanese studied this family of mosquitoes, known as the Aedes aegypti. Researchers checked which human blood group is most tempting for the species.
It turned out that mosquitoes bite people with blood type O almost twice as often as those with other groups. The second most bitten is type B, followed by AB, and finally, A.
The study's authors emphasise that the preferences may be related to the fact that this mosquito species likely evolved in Africa, where blood type O is the most prevalent.
For a long time, the yellow fever mosquito spread mainly in Africa, South America, and Asia. However, it can now be found all over the world. In December 2023, the World Health Organization (WHO) warned about its appearance in Europe.
The danger increases with climate change and the associated rise in temperatures - explained WHO specialist Diana Rojas. Also, in Germany, health authorities are reporting an increasing number of dengue fever cases caused by this mosquito.
With this blood type, you are a delicacy for mosquitoes, but other factors are also important
Scents play an essential role in insects' choices. Mosquitoes prefer certain people due to what scientists call "volatile substances" or scents.
Biologists from Johns Hopkins University in Baltimore, in a study published in June 2023, proved that CO2 and other scent signals from the human body are the most significant for mosquitoes. Thermal and visual aspects are also significant for them.
Mosquitoes seem to prefer people whose scent contains a mix of carboxylic acids and fatty secretions that keep our skin moisturised and protected. "Two of these carboxylic acids are also found in Limburger cheese", said McMeniman, the study's lead author, to "Nature".
The bad news for outdoor grilling fans is that an elevated alcohol level in the blood attracts more mosquitoes. Additionally, the more carbon dioxide someone exhales due to body weight and breath depth, the sooner they are detected by a mosquito.
According to scientists, mosquitoes detect odours through olfactory neurons in their antennae. They can sense body odour from up to 60 metres away, and sensing body temperature helps them reach their target.
However, the belief that light attracts mosquitoes is a myth. On the contrary, dark clothing makes us more likely to fall victim to these attackers.
