TID-BITS #2:  INSECT REPELLENTS

I have received numerous requests from customers for an herbal insect repellent. The concern and need for protection against insect bites has become a necessity because diseases that they can carry -- such as West Nile Virus and Lyme’s Disease -- are wide-spread in the United States. It is important to know which repellent products can safely provide adequate protection.

As I began my research on the many herbs and essential oils known to deter insects, I came upon an article issued by The New England Journal of Medicine dated July 4, 2002, entitled "Comparative Efficacy of Insect Repellents Against Mosquito Bites". I felt compelled to provide my customers with some interesting facts that resulted from that study.

This independent study was conducted within the Florida Medical Entomology Laboratory at the University of Florida, using both male and female volunteers, in a controlled environment, to reflect typical insect biting conditions. Insect repellents used in this study contained either synthetic chemicals or botanical-based products, which basically means, DEET or plant-derived essential oils. Specific products were not discussed - only product content. The information provided here is based on this article, unless indicated otherwise.

DEET-BASED PRODUCTS

DEET is a chemical compound repellent that has been used worldwide since the 1950’s, and is effective against many species of mosquitoes, biting flies, chiggers, fleas, and ticks. It has been subjected to more scientific scrutiny than any other repellent substance because of the public’s concern over its toxicity and possible side effects. There are yearly reports of adverse skin reactions to people using DEET products, however, this report stated that fewer than 50 cases of serious toxic effects have been documented since 1960. In 1998, the Environmental Protection Agency concluded that "normal use of DEET does not present a health concern to the general U.S. population." Currently available products contain around 30% or less DEET concentration. The "average" formulation containing around 23% provided an average of five hours of complete protection after a single application. In this and numerous other reports, it is suggested that where DEET is concerned, more is not necessarily better. In fact, formulations of 40% or higher showed no additional protection. It was recommended that until a better repellent becomes available, DEET-based products, when used properly, can provide a safe, long-lasting repellent – a range of 2-6 hours of protection with one application. In several other articles I researched, it is repeatedly recommended that products used on children and pregnant women should contain less than 10% DEET. Common sense and basic precautions should be observed when using any product. I will address these recommendations later in the brochure because they apply to both chemical and botanical products.

BOTANICAL REPELLENTS

This study showed that most botanical repellents available at the time of the study contain one or more of the following essential oils: citronella, cedar, eucalyptus, peppermint, lemongrass, geranium and soybean. These oils showed repellent effects when used alone or combined. Other studies determined that the following essential oils also have repellent activity: verbena, pennyroyal, lavender, pine, cinnamon, rosemary, basil, thyme, allspice, garlic, and catnip.

The NEJM study found that botanical repellents can be effective, but the protection is not long-lasting as compared to DEET-based repellents. They noted the following: Oil of eucalyptus, a range of 60 to 200 minutes; Soybean oil, between 60 and 90 minutes. Citronella-based repellents protected for 20 minutes or less.

In an article written by the American Chemical Society, dated August 2001, entitled "Catnip Repels Mosquitoes More Effectively than DEET", Entomologist Chris Peterson conducted laboratory tests in glass tubes using Nepetalactone, a component in the essential oil of Catnip. Dr. Peterson concluded that Oil of Catnip was ten times more effective at repelling mosquitoes than DEET. However, the article also noted that no animal or human tests had yet been conducted to further substantiate this theory.

Another article, dated June 2002, relates a discovery by Dr. Michael Roe, Entomologist at the University of North Carolina. Dr. Roe has been researching a tomato-derived substance that he has found to be just as effective and less harmful than DEET. As of the date of the article, they were awaiting EPA’s approval to use this substance as an insect repellent.

CONCLUSIONS

The NEJM study team concluded that "only products containing DEET offer long-lasting protection after a single application. Certain plant-derived repellents may provide short lived efficacy, which may be sufficient when arthropod bites are primarily a nuisance. Frequent reapplication of these repellents would partially compensate for their short duration of action. However, when one is traveling to an area with prevalent mosquito-borne disease that could be transmitted through a single bite, the use of non-DEET repellents would seem to be ill-advised. Given our findings, we cannot recommend the use of any currently available non-DEET repellent to provide complete protection from arthropod bites for any sustained outdoor activity." I’ve read numerous articles regarding the effective repellent properties of many of the essential oils and herbs listed above.

Unfortunately, botanical repellents have been relatively poorly studied. I limited the information offered in this brochure to the NEJM study results.

I could spend months researching every aspect of this subject. It certainly is multi-faceted and research continues to yield encouraging results for those of us interested in a safer, natural alternative to chemical products. I believe the NEJM study was one of the most comprehensive, unbiased research studies I came across, and it provided facts that may be helpful in choosing an insect repellent that suits your needs. Under "Contacts" at the end of this brochure, I list a few organizations for you to contact if you want additional information.

PRECAUTIONS

Keep in mind that regardless of the type of product you use, it is imperative that you follow the precautions listed on the product label. Essential oils, though natural ingredients, are intensely strong and can cause skin irritations as do the chemical products. I have compiled a comprehensive list of precautions to follow when using an insect repellent, whether chemical OR botanical. Many of these were issued by the Environmental Protection Agency (EPA) -- others I gathered from additional research:

• Never use any type of repellents over cuts, wounds, or irritated skin, including sunburned skin.

• Never apply to eyes and mouth, and apply sparingly around ears.

• First try applying a product to clothing rather than skin. If that is not effective, then apply to exposed skin only – not under clothing.

• If using a spray, do not spray onto face – spray onto hands and then apply to face.

• If possible, avoid areas where insect infestation and nesting -- especially mosquitoes -- is known to be high.

• If using both sunscreen and insect repellent, apply the sunscreen first, wait 30 minutes before applying the repellent to allow time for the sunscreen to be absorbed into the skin.

• Avoid higher concentration products on the skin, particularly with children.

• Do not spray in enclosed areas or around food and avoid inhaling the spray.

• Apply a thin film first, and if that is not effective, then apply more.

• After returning indoors, wash treated skin with soap and water. Also wash treated clothing before wearing it again.

• Wear light colored clothing so as not to attract bugs.

• Avoid using any scented soaps or other products -- especially on young -- children because the fragrance can attract insects.

• Re-apply repellent when involved in activities such as swimming or sweating, which could cause the repellent to be washed off the skin.

• Note that most insect repellents do not protect against stinging insects such as wasps and bees.

• Use a lower concentration of DEET for pregnant women, and small children. The EPA recommends 10% or less, and never use on a baby 3 months old or younger.

• Children 2 years old and younger should not have insect repellent applied to their skin more than once in a 24-hour period.

• Especially for children, make sure as much of their skin is covered with clothing as possible.

• Do not apply to children’s hands as they are more likely to rub their eyes or touch their mouth with their hands.

• Do not allow children to handle ANY repellent products.

• Follow product instructions, including age restrictions.

This list is comprehensive, but not completely exhaustive. However, if all of these precautions are observed, I believe a repellent product can be used effectively and safely. Remember that just because a product is "herbal" or "natural", it does not mean it is harmless. Essential Oils are extremely concentrated and a person can have an allergic reaction to its use just as some people are allergic to certain foods or cosmetic ingredients. If you have sensitive skin and are prone to allergic reactions, you may want to try a product on a sensitive area of skin - such as the underside of your wrist - to see if it gets irritated, before you use it all over your body!

‘DEES BUG STUFF"

I consider myself a novice in the world of herbs and essential oils. So to concoct a safe, effective insect repellent, I turned to professionally trained herbalists for a reliable recipe. My search eventually led me to one of my favorite books, Herbal Treasures by Phyllis Shaudys. "Dee’s Bug Stuff" is a recipe developed by Herbalists Mike and Jen Mescher, because it contains a combination of some of the best-known plant-based insect repellents: pennyroyal, eucalyptus, citronella, and cedarwood. I use Soybean Oil as the base (carrier) oil instead of the recommended Sweet Almond Oil for several reasons: by itself it is reputed to repel insects; it contains Vitamin E which is nourishing and soothing to the skin; it doesn’t leave a greasy film; it has a shelf life of up to 16 months; and it’s much less expensive that most base oils used for topical applications.

CONTACTS

There is a wealth of information available at any library, bookstore, and on the internet. Here are just a few organizations to contact for further information:

A copy of the NEJM article can be obtained

by contacting them at 1-800-843-6356 or at

www.nejm.org (in their search function type in "DEET")

Environmental Protection Agency’s National

     Pesticide Information Center (NIC)

1-800-858-7378 or at www.npic.orst.edu

U.S. Department of Health and Human Services

National Institutes of Health

(301) 496-4000 or www.nih.gov

The Herb Society of America

(440) 256-0514 or at www.herbsociety.org/

Herb Research Foundation

(303) 449-2265 or www.herbs.org