According to the World Health Organisation, more than 250 million people worldwide are infected with malaria – a disease that kills more than 650,000 people each year, most of them in sub-Saharan Africa.
Researchers at the University of Neuchâtel in Switzerland have been working on a new, highly effective and environmentally safe mosquito repellent. Their study is based on the behavior of mosquitoes. The idea is to disturb their attraction to humans.
In nature, mosquitoes detect people through volatile molecules emitted by the human skin, their breath or their temperature.
Scientists checked what nature had to offer. They found that a special mixture of essential oils was about as effective against malaria mosquitoes as repellents like the highly toxic chemical, Deet.
“Deet is a well known repellent, but it is known to have neurological effects. It affects synapses between neurons, that’s well known. So it affects some of the enzymes, for example, that are normally used to decompose some of our neurotransmitters. Our natural products do not have these characteristics,” explained Patrick Guerin, head of research at the Department of Animal Physiology at the University of Neuchâtel.
The researchers analysed the extracts of 80 plants and developed the repellent which is both safe for humans to use and environmentally-friendly as well as fully biodegradable.
They subjected it to a number of tests: they looked at the mosquitoes’ behaviour when exposed to a typical human odour, for example a sock impregnated with sweat. When the repellent was applied to the sock, the mosquitoes were no longer attracted to it.
The Swiss scientists are convinced their discovery is just the beginning of a new wave of breakthroughs in this field. It is hoped in the future, natural extracts of essential oils could play an important role in limiting the number of victims from disease-carrying insects.