Field efficacy of metofluthrin - a new mosquito repellent

Abstract:
SumiOne® (common name metofluthrin, 2,3,5,6-tetrafluoro-4-methoxymethylbenzyl (E,Z) (1R,3R)-2,2dimethyl-3-(prop-1-enyl) cyclopropane carboxylate) is a novel vapor active pyrethroid that is effective against mosquitoes. Impregnated paper substrates have been shown to be effective at dispensing metofluthrin though passive evaporation at room temperature. The rate of evaporation has been studied and shown to decline gradually over time. Field trials were conducted in the United States to evaluate the repellent activity of paper substrates (“emanators”) each treated with 200 mg metofluthrin. To determine the duration of protection treated emanators were pre-aged for 36 hours in a wind tunnel. Trials were conducted in Florida and Washington State, with 5 volunteers being used in each trial. Each volunteer was protected from biting by Tyvek® suits and head nets and was positioned between two paper emanators that were suspended 8 feet apart. Each emanator consisted of a folded piece of thin paper with a surface area of 4000 cm2. (This measurement includes both sides of the device). Pre- and post-treatment landing counts were conducted at 2-minute intervals for a maximum of 30 minutes. In the Washington trials, where Aedes vexans was the dominant species, an average of 26 mosquito landings per minute were observed prior to treatment. Greater than 95% landing reductions were observed in all but 3 tests, where reductions were still greater than 85%. In the Florida trials, higher mosquito density (mostly Ochlerotatus spp.) was observed with an average of 32 landings per minute observed prior to treatment. Seven treatments failed to provide greater than 95% landing reductions, but overall mean reductions in these treatments were greater than 80%. Results demonstrate that metofluthrin treated emanators are effective at repelling mosquitoes under outdoor conditions.