The threat of insect-transmitted diseases makes it necessary to think about skin protection during summer outdoor activities. Tick-borne diseases include Lyme disease and Rocky Mountain spotted fever, and mosquito-borne diseases include West Nile Virus and other types of encephalitis.
There are many products touted as effective against bug bites, but the DEET-containing products remain at the top of the class. DEET (diethyl methylbenzamide) is the chemical used in insect repellents that’s been shown to be the most effective against mosquitoes, ticks and other arthropods. DEET has been studied more than any other repellent since its introduction in the 1960’s.
Though some still question its safety, there have been fewer than 50 serious cases of toxicity involving the chemical in an estimated 8 billion human applications. These cases occurred when using higher concentrations of the chemical on larger surfaces of the body. Current applications give a concentration of about 10 percent to 30 percent DEET. It is, however, still not recommended for children under the age of 2-3 months.
In a study published in the New England Journal of Medicine in 2002, DEET was tested along with several other “claimed” insect repellents. DEET-containing repellants provided the most lasting protection from mosquito bites (about 5 hours). In second place, soybean oil warded off the bugs for about 90 minutes. Other botanical repellents containing any of the following: citronella, cedar, eucalyptus, peppermint, geranium or lemongrass, all gave protection for less than 20 minutes.
Another chemical, ethyl butylacetylaminopropionate, which is in Skin So Soft, provided protection for less than 10 minutes. Previous studies on sound emitting devices showed them to be generally ineffective. Wristbands impregnated with repellents were effective only within a range of about 2 inches from the band.
Mosquitoes are attracted to smells at close range. Soaps, perfumes and hair products that have a floral fragrance will tend to draw mosquitoes. Dark clothes and body heat are also attractants.
From a distance of about 100 feet, mosquitoes can detect carbon dioxide given off from human breath and skin. This is the basis for some backyard mosquito traps that lure the bugs by emitting carbon dioxide and then trap and kill them. These traps are an evolving technology and studies on their overall effectiveness are still ongoing. They seem to be effective in trapping large amounts of mosquitoes, but they might also attract an additional larger number of bugs to the surrounding area.
There are other reported repellents that lack any scientific study to verify their effectiveness. These include topical Vick’s Vaporub, rubbing fabric softener sheets on the skin, ingestion of garlic capsules and daily vitamin B1 tablets (thiamine).
In general, some simple steps may reduce mosquito bites. These include using fragrance-free cosmetics, choosing lighter colored clothing and wearing long sleeves and pants to cover the skin. These measures, along with the application of a 10 percent to 30 percent DEET containing repellent, should greatly reduce your chance of getting bugged by the bugs.
The content in this column is for informational purposes only. Consult your physician for appropriate individual treatment. Dr. Reynolds practices Family Medicine in Chesterfield.