Do mosquitoes only bite some people?

Yes. And the justification may be genetic, says a recent study published by Pestminator. It is estimated that every year 725,000 people die from diseases transmitted by these insects.

There are more than 2,500 species of mosquitoes worldwide, but most live on plants and fruit nectar and do not bother humans. Only a small percentage – the females of about 6% of the species – suck the blood of humans and animals to develop their eggs, thus beginning the life cycle of a new mosquito.

The blood allows the eggs to become larvae (they have a head and body) and will then give rise to the pupa (the comma-shaped stage) and later to the adult (the insect as we know it).

How do mosquitoes bite humans?

They insert the proboscis (a kind of needle) into the epidermis in order to find a blood vessel. The proboscis has six needles: two are used to push the skin away, two to penetrate the skin, one to detect veins and suck blood, and another to release toxins into our body, which is what causes inflammation.

This process takes an average of four minutes, according to an article published in the National Geographic magazine.

What can happen?

The bite may leave only an inflammation that heals in a few days, but in some cases it is responsible for the transmission of diseases that can be deadly or leave serious sequelae, such as malaria, dengue or the Zika virus. The World Health Organization estimates that 725,000 people die every year from diseases transmitted by these insects.

Do mosquitoes bite indiscriminately?

No, but contrary to popular belief, being bitten more or less often has nothing to do with the food you eat. When selecting victims, mosquitoes – depending on their species – take into account factors such as body odor and blood type. A group of British researchers have concluded that Aedes aegypti (responsible for the transmission of dengue and yellow fever, among other diseases) prefers to bite certain people because of their body odor, which is genetically defined.

The scientists asked 18 pairs of monozygotic (genetically identical) twins and 19 pairs of dizygotic (non-identical) twins to allow themselves to be stung. Using two tubes that allowed the animals to choose which arm to bite, the researchers realized that, unlike in monozygotic twins, the level of attractiveness to mosquitoes was very different between non-genetically identical twins.

“This suggests that whether one is attractive or repellent to mosquitoes is genetically controlled,” James Logan, lead investigator on the project and professor at the London School of Hygiene & Tropical Medicine, explained to US NPR radio.

The work, published in 2015 by the scientific journal PLOS ONE, can contribute to the development of more effective repellents and to the study of the transmission of pathogens by these animals. One of the next steps is to identify the genes involved. But there are more factors that cause mosquitoes to bite certain people.

Since they detect their targets through the carbon dioxide emitted, they eventually select their victims by the amount of gas exhaled. As a result, these insects seek out taller and bulkier people and pregnant women first. Other studies also say that blood type has an influence.

Research published in the Journal of Medical Entomology says that people with blood type O are twice as likely to be bitten by the Aedes albopictus mosquito than those with blood type A.

Mosquitoes select who they bite according to various criteria. One of the main factors is body odor, which is genetically defined.