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Health eTips is produced by the staff of the St. Charles County Department of Public Health. The department consists of three divisions - Environmental Health and Protection, Health Services and Humane Services - that provide a wide range of services focused on enhancing the well-being of this community.

If you have questions about the Department of Public Health or have suggestions on public health topics you'd like to see explored in this blog, please email us.

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Sep 10

Insect Repellent

Posted on September 10, 2018 at 3:07 PM by Doug Bolnick


Wonder why your neighbor can enjoy a peaceful evening in the backyard, while you seem to be the target for every mosquito within 50 miles? Research indicates that the body’s release ofPhoto demonstrating how to apply mosquito repellent. carbon dioxide, lactic acid and other cues trigger the bite reaction by female mosquitoes. But, be comforted that these cues can be masked by using insect repellent.

What Makes the Best Repellent?
The most effective repellents contain the chemical N1N-diethyl-m-tolumide — known as DEET — which is proven to be effective against biting insects. First developed by the U.S. Army in the 1940s to protect soldiers, the product has been readily used by consumers since 1957.

The manufacturer’s ingredient label indicates the percentage of DEET found in the product. The higher the percentage, the longer the application will be effective. For example, a 5 percent product should provide about 90 minutes of protection, while a 30 percent formula protects for approximately six hours.

Those who choose not to use products containing DEET can select Centers for Disease Control and Prevention (CDC) recommended products that contain:
  • Picaridin - a synthetic compound developed by the Bayer Corporation in the 1980s.
  • IR 3535 – a synthetic biopesticide owned by Merck KGaA.
  • Oil of lemon eucalyptus - a refined product using the essential oils of the lemon-scented gum tree (also known as the lemon eucalyptus tree). The CDC cautions that this product should not be used on children under 3 years of age.

How Should the Product Be Applied?
Repellents should be applied to exposed skin and on top of clothing.
  • If you’re headed outdoors during daylight hours, apply insect repellent after sunscreen for maximum effectiveness. Sweating or swimming may cause the products to wear off; reapply as needed.
  • Do not apply aerosol sprays directly to your face or on infants, but instead spray to your hands and rub on exposed areas. Avoid the mouth, eyes and nostrils.
  • Do not apply repellent to cuts or open sores.
  • After application, wash your hands with soap and water.

Are There Other Methods to Protect Against Biting Insects?
In addition to wearing repellent, there are other things you can do to reduce insect populations and biting opportunities.
  1. Fill in or drain areas where water may settle for more than one week.
  2. Empty watering cans, wading pools and other containers after use. Remove trash and debris from yards. Keep lawns trimmed to minimize habitat.
  3. Wear long-sleeved shirts and long pants outdoors. Choose light-colored, loose-fitting clothing.
  4. Avoid areas known for biting insects, including tall grass and wet or wooded habitat.
  5. Burn citronella candles to deter mosquitoes.
  6. Plant marigolds, lemon grass or lavender in your garden to repel insects and add beauty.

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