Since the arrival of West Nile virus, pediatricians have changed their advice about the use of the most effective insect repellents, which contain the active ingredient DEET. Adverse reactions to using DEET are extremely rare and confined to situations where the product was not used in accordance with the label instructions. The risk of the virus or of Lyme disease from ticks is much greater than any risk from using DEET. On the other hand, there is no reason to use repellents with very high concentrations of DEET. More DEET doesn't keep mosquitoes away better; it just makes the protection last longer. We've gotten good results even among thick, Alaskan mosquitoes from DEET-based repellents made for children with a 7.5% concentration, reapplying every couple of hours. However, the American Academy of Pediatrics now says even 30% concentrations are safe on kids when used correctly. But you must be careful: Have an adult apply the repellent, and keep it away from ears, eyes, mouth, or fingers the child might put in his or her mouth. Experts disagree on using it on very young children. Some say it is acceptable on babies over 2 months in low concentrations; others say 2 years. There is a good alternative, especially with babies: netting. For more advice on DEET, see the Centers for Disease Control's West Nile Virus website, and call your local doctor.

Early in 2005, though, the CDC also approved the use of non-DEET repellents that contained picaridin, a chemical long used in Europe and Latin America, or oil of lemon eucalyptus, a plant-based compound. Cutter makes a product, called Advanced, that contains picaridin, while the makers of Burt's Bees products have a repellent with oil of lemon eucalyptus. I've tested this in the Yellowstone backcountry and found it to stand up well to mosquitoes -- and it smells a lot better than DEET! Your children may have allergies, so, as always, consult your own doctor before using anything new.

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