Efficacy of repellent products against caged and free flying Anopheles stephensi mosquitoes.
The efficacy of 9 repellents (8 commercial repellents and one product under development) was evaluated on the skin at dosages of 0.65 and 1.7 mg of product/cm2, the latter dosage being the industrial standard for deet based repellents. The repellents were applied to the arm or lower leg of a human subject and tested against Anopheles stephensi in a cage or flying freely in a mosquito-proof room. In the cage tests, a product with 20% p-menthane-3, 8-diol (PMD) active ingredient provided complete repellency for 7-8 hours, while with 10% PMD had complete repellency for only 30 minutes. The natural oils of clove (Syzygium aromaticum) (10% active ingredient) plus makaen (Zanthoxylum limonella) (10% active ingredient) gave protection for 4-5 hours. In the case of free flying mosquitoes, products with 20% and 30% PMD gave complete protection for 11-12 hours at a dosage of 1.7 mg/cm2 or 6 hours at half the dosage, while the product with 10% PMD afforded protection for less than 2 hours. At the higher dosage rate 40% citronella and hydroxyethyl isobutyl piperidine carboxylate, a new synthetic compound, provided complete repellency for 7 hours. Fifty percent deet (N,N-diethyl-3-methylbenzamide) was effective for 30 hours if left undisturbed on the skin.
Trongtokit
Yuwadee
Y
London School of Hygiene and Tropical Medicine, London, UK. tmytt@mahidol.ac.th
Curtis
Christopher F
CF
Rongsriyam
Yupha
Y
D000818:Animals; D000852:Anopheles / Q000187:drug effects*; D001733:Bites and Stings / Q000517:prevention & control*; D031743:Cymbopogon; D003671:DEET / Q000008:administration & dosage / Q000494:pharmacology; D006801:Humans; D007302:Insect Repellents / Q000145:classification / Q000494:pharmacology*; D007306:Insecticides / Q000494:pharmacology*; D008610:Menthol / Q000008:administration & dosage / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology*; D010938:Plant Oils / Q000008:administration & dosage / Q000494:pharmacology
D007302:Insect Repellents; D007306:Insecticides; D010936:Plant Extracts; D010938:Plant Oils; D003671:DEET; D008610:Menthol