This research opens the way to develop repellents or “traps” to deceive mosquitoes that can spread diseases such as malaria, dengue or Zika
A group of researchers has discovered an important part of how mosquitoes focus on human heat to find and bite people. This study has been published by the scientific journal ‘Science‘.
The findings represent the first time researchers have identified some of the genes and cells responsible for attracting heat by mosquitoes. Its importance is that it opens the way to develop repellents or “traps” to deceive mosquitoes that can spread diseases such as malaria, dengue or Zika.
“Everyone knows that mosquitoes are annoying: they bite and they are everywhere. But we still have some question marks about the underlying basic mechanisms that drive them. This study really addresses that knowledge gap,” says the biology professor Paul Garrity, lead author of the research.
The researchers focused on receptors that, traditionally, were thought to act as thermometers, taking the temperature of the environment so that the insect knew if the environment was hot or cold. Instead, Garrity and his colleagues discovered that the receptors only detected if the temperature was changing, letting the insect know if things were heating or cooling.
For this reason, Garrity renamed these temperature sensors, from an extreme sensitivity capable of detecting a change of hundredths of a degree in a second, such as cooling cells and heating cells. In addition, he considered an alternative hypothesis: mosquitoes may not have flown into the heat, but escaped the cold, which would mean that the cooling cells were the ones that guided them.
Thus, the cooling cells, or IR21a receptor, are activated each time the mosquitoes move to a colder temperature. Since human beings are generally warmer than their surroundings, this means that as a mosquito approaches a human, IR21a remains silent. But if the insect deviates from its path and begins to move away from its hot-blooded prey, IR21a activates, it only turns off once the insect corrects the course.
Thus, the researchers were conducting laboratory tests, inhibiting this receptor in mosquitoes, and showed that those insects that lacked it showed no interest in hot blood. However, disabling IR21a is not enough to completely disconcert the mosquitoes, as they returned to show interest when they were “offered”, as a claim, the bare hands of the researchers. In this way, although it is a valuable investigation, further study is still needed to learn how mosquitoes are guided to locate and bite us.