Prophylactic measures against mosquitoes include Using permethrin - or pyrethrum-containing residual insecticide sprays (which have prolonged duration of action) Placing screens on doors and windows Using mosquito netting (preferably impregnated with permethrin or pyrethrum) around beds Treating clothing and gear (eg, boots, pants, socks, tents) with products containing 0.5% permethrin, which remain protective through several washings (pretreated clothing is available and may protect longer) Applying mosquito repellents such as DEET (diethyltoluamide) 25 to 35% to exposed skin Wearing protective long-sleeved shirts and pants, especially between dusk and dawn, when Anopheles mosquitoes are active People who plan to use repellents that contain DEET should be instructed to Apply repellents only to exposed skin as directed on the label and use them sparingly around ears (they should not be applied to or sprayed in the eyes or mouth).