When outdoors in an area where dengue fever has been found: Use a mosquito repellent containing DEET, picaridin (KRB 3023 or icaridin), oil of lemon eucalyptus, para-menthane-diol (PMD) or 2-undecanone. Dress in protective clothing, including long-sleeved shirts, long pants, socks and shoes. Treating clothing, bed nets and gear with permethrin can also help.