Vail doc: Don’t let the bad bugs bite |

Vail doc: Don’t let the bad bugs bite

Dr. Drew Werner
Vail Valley, CO Colorado

As Hippocrates said long ago, in an oath Doctors still take upon graduation from medical school: “Do no harm.” We are continuously challenged with that very premise. Are insect repellents safe? Which is worse: the disease or the cure? Isn’t there something natural I can use? All are good questions when it comes to insect repellents.

Dear Doc,

I know it is important to use insect repellents, but I want to use something natural and safe. What are my best choices?

A Mom in Eagle

Dear Mom,

There is a lot of controversy about insect repellents, largely revolving around the ones containing DEET. Also known by its chemical name N,N-diethyl-3-methylbenzamide, DEET is both the most effective and most-studied insect repellent known. Before the widespread presence of West Nile Virus, mosquitoes in the U.S. were mostly a nuisance. The decision to use an insect repellent for a local reaction was a matter of individual preference and based on how bad people reacted to the bite. Now with the emergence of the West Nile Virus, the reasons to use a repellent have become more compelling. Although diseases including malaria are a worldwide concern for millions of people, in the U.S., West Nile Virus is the only major mosquito transmitted disease. Nevertheless, we all should consider using insect repellents.

What are our choices? Certainly avoiding the outdoors, or wearing long sleeve shirts and pants if you are outdoors, helps. Realistically though, we need some other options. These come in the way of electronic mosquito deterrents, insecticides and insect repellents containing DEET or natural products such as plant oils and citronella. Electronic agents may help against flies and other insects, but offer little protection against mosquitoes. Currently, insecticides have limited personal use. Such products containing Permethrin are approved for application on clothing or fabrics only. While very effective, directions for use should be followed carefully. That leaves DEET and other synthetic and natural repellents. They have been broken down into two categories by the Environmental Protection Agency (EPA).

• Conventional repellents, which include DEET and Picaridin, as well as Biopesticide repellents, which include Oil of Lemon Eucalyptus, p-Mentane-3,8-diol (the synthisized chemical equivalent of Oil of Lemon Eucalyptus), Methyl nonyl ketone (originally developed in 1966 as an animal training aid), IR3535 or Merck 3535 (released in 1999 after more than 20 years of use in Europe with no significant harmful side effects) and Citronella, which has no proven benefits in commonly found candles, but is helpful when used in products which allow direct application to the skin.

Each of these products has been tested by the EPA and found to be effective, and safe if used as directed. That is perhaps the most important “take home” point. Pay attention to the concentration of the active ingredient, apply correctly, and use particular care with children. Surprisingly, some like DEET are actually approved for all ages (although I agree with the American Academy of Pediatrics recommendation to use in infants over the age of two months), while others like Oil of Lemon Eucalyptus should not be used in children below the age of three years. Each is considered effective by the EPA, although they are not all equally effective. Try one, and if you find yourself swatting mosquitoes after using it properly, move on to another repellent. The concentration of the active ingredient has more to do with the duration of benefit than the effectiveness of the insect repellent, so consider how long you will be outdoors when choosing the concentration or plan on reapplying as bugs begin to bite. Finally, it is important to know that we are not all equal in terms of how attractive bugs seem to find us. There may be significant differences from person to person in the number of bites in the same environment. I seem to rarely get bitten, while my son wonders if he would have any blood left should he spend too much time outside without his bug spray.

In order to use DEET and other repellents safely, follow these guidelines:

• Only apply insect repellents to exposed skin, taking care to avoid the eyes and mouth.

• Do not apply on wounds or scratches.

• Do not apply to the hands of small children, since they frequently put their hands into their mouths.

• Do not allow children to apply the product themselves.

• Avoid over-saturation — it’s not necessary for adequate protection.

If you or someone you are with has a possible toxic exposure to an insect repellents, or any other poisonous exposure good numbers to have on hand are the Rocky Mountain Poison Control Center at 1-800-332-3073, or the National Poison Control Center at 1-800-222-1222, which will put you in contact with the closest poison control center anywhere in the U.S.

Dr. Drew Werner is the vice chief of staff at Valley View Hospital in Glenwood Springs and the Eagle County Health Officer. He lives in Eagle with his family. E-mail comments about this column to

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