Repellent studies with Aedes aegypti mosquitoes and human olfactory tests on 19 essential oils from Corsica, France

Abstract

In order to reduce the risk of getting infected with any epidemic disease transmitted by mosquitoes, repellent products are often used to protect populations at risk. The repellent potential of 19 essential oils from the island of Corsica, France, was evaluated in a bio-assay with the mosquito Aedes aegypti, in order to assess the 'space repellent' properties of these oils. Lavendula stoechas, Helichrysum italicum (leaves) and Laurus nobilis oils showed a capability of reducing the attractivity of a human finger for yellow fever mosquitoes in a Y-tube olfactometer. In addn. to the behavioral studies on mosquitoes, two tests on the olfactory perception of these 19 oils were performed, involving 25 female and 25 male human volunteers. The aspects studied were the 'hedonic dimension' of these oils and their acceptance as a final fragrance for a repellent formulation. The expts. yielded promising results concerning both aspects for three oils, from Calamintha nepeta, Laurus nobilis and Rosmarinus officinalis, with minor differences between male and female participants. Laurus nobilis oil was the only oil tested fulfilling both properties: a spatial repellent effect on Aedes aegypti and acceptance by the volunteers for its integration in a repellent product. Thermogravimetric anal. showed that Calamintha nepeta oil has a slower evapn. rate in comparison to the Laurus nobilis and Rosmarinus officinalis oils.