The mayor of Dallas, Texas, just declared an emergency, after 10 confirmed deaths in his city were attributed to West Nile, and the Texas Department of State Health Services has confirmed 17 deaths across the state. Further north, a few cases of the rare eastern equine encephalitis, another mosquito-borne disease that can be fatal, have been found in mosquitoes in Massachusetts. MORE: Why Mosquitoes Bite You More Than Your Friends But before you grab the nearest mosquito fumigants, stop! DEET, the most commonly used active ingredient in mosquito repellents, comes with some disturbing health problems, having been linked to everything from birth defects to neurological damage. To add insult to injury, a study in the Proceedings of the National Academy of Sciences found that some disease-carrying mosquitoes are growing resistant to DEET. Female mosquitoes that carry dengue fever (yet another disease that has spread from the tropics to 28 US states) were not deterred by DEET—and they even passed that DEET-resistant trait to their offspring. The good news is that these natural insect repellents are just as effective—if not more so—than DEET: Picaridin A chemical derived from pepper, picaridin has shown the most promise as being an effective DEET replacement without any negative health effects. In fact, a study published in the 2004 issue of the journal Tropical Medicine & International Health found that picaridin was more effective at repelling dengue-fever-spreading mosquitoes than DEET. You can find picaridin-containing products at most national drugstores. One option: Cutter 53663 Advanced 6-Ounce 7% Picaridin Insect Repellent Pump Spray ($6.89, amazon.com) Oil of lemon eucalyptus The only plant-based repellent recommended by the Centers for Disease Control and Prevention, oil of lemon eucalyptus is effective for warding off disease-carrying mosquitoes. A 2004 study in the Journal of Medical Entomology found that products containing 26% oil of lemon eucalyptus protected against West Nile virus-carrying mosquitoes for about three hours longer than products containing 7% DEET. Look for products carrying at least 26% oil of lemon eucalyptus, such as Repel HG-406T Lemon Eucalyptus 4-Ounce Insect Repellent Pump Spray ($12.60, amazon.com). IR3535 It sounds more like a tax code than an insect repellent, but this ingredient, found in Avon Skin So Soft, was shown to be as effective as DEET against West Nile–carrying bloodsuckers, according to a study in the Journal of Medical Entomology. It’s a synthetic version of amino acids found in vitamin B, and has been used for decades in Europe with no reported adverse side effects. Other plant-based repellents That same Journal of Medical Entomology study also looked at products containing soybean oil, citronella, neem oil, and geraniol (the oil found in geraniums), and found that while all were effective against mosquitoes for up to three hours, soybean oil was the most effective of the four. Soybean oil worked for more than seven hours, just as long as products containing 15% DEET, picaridin, oil of lemon eucalyptus, and IR3535. Geraniol was next in line, warding off bugs for up to five hours, followed by citronella and neem oil, which worked for three hours before needing to be reapplied. MORE: How To Soothe Mosquito Bites
