EFFECT OF SKIN ABRASIONS ON THE EFFICACY OF THE REPELLENT DEFT AGAINST AEDES-AEGYPTI

Abrasion of repellent-treated human skin affected the efficacy of a su stained-release insect repellent containing N,N-diethyl-3-methylbenzam ide (deet) against bites of Aedes aegypti. Skin treated with repellent when abraded up to 30 times showed significantly lower protection tha n unabraded skin against mosquito bites for 10 h. The mean value of th e kinetic coefficient of friction during skin abrasion by clothing (ba ttle dress uniform fabric) for repellent-treated skin (0.159 +/- 0.003 ) was significantly higher than untreated skin (0.122 +/- 0.005). Repe llent-treated skin appeared stickier than the untreated skin. An incre ase in the number of skin abrasions by clothing resulted in a reduced duration of protection against mosquito bites.