New Anti-Mosquito Control Focusing on Mosquito Wetting

Mosquitoes are one of the most dangerous animals on earth to humans. Mosquito-borne diseases such as dengue fever and malaria kill more than 700,000 people every year, most of them children under the age of five.
Kao wants to protect future lives that could be saved if they can avoid the mosquito bite, while making it possible for families to spend quality time together every day. For this reason, we have been developing anti-mosquito products that can be used by the whole family and that are close to our daily lives, and have been conducting the basic research necessary to achieve this goal.

The surface of a mosquito’s body has fine structures like scales and hairs, each of which is covered with a wax-like substance. While these structures make a mosquito’s body extremely water-repellant, we have found that they can be quickly wetted by silicone oil and surfactant solutions, which are commonly used in cosmetics and daily necessities.

When a mosquito attempts to land on a silicone oil-applied surface, its legs get wet and are pulled into the oil, causing the mosquito to immediately fly away. This enabled a new physical action to repel mosquitoes, different from conventional repellents that use volatile compounds.

We also found that spraying a surfactant solution wetted the wings of the mosquitoes, and that the mosquitoes could not move their wings well enough to fall off. In particular, surfactant solutions with a low surface tension have been found to not only make mosquitoes fallen but also induce a knock-down state. This has made it possible to get rid of mosquitoes without the use of conventional synthetic chemical insecticides.