Almost time to buy bug spray…
By Dr. Derrick Adams
With all the late spring rains and warmer winter we had this year, I fear we may be in for a bad mosquito season. The human buffet will be open shortly. With all the headlines about the dreaded Zika and West Nile virus, people will be stocking up on insect repellent quite soon.
But what to buy?
We are all familiar with old fashioned DEET. It has been around since World War II. In response to consumer fears surrounding DEET, companies have scrambled to come up with a safe alternative. There seems to be as many mosquito repellents as there are mosquitoes these days. And few head-to-head studies have been done to any large degree.
If you are a regular reader of the Journal of Insect Science, you are probably familiar with the study conducted at New Mexico State University recently. They tested 10 available products against two common species of mosquitoes. Three products contained DEET (Repel 100® Insect Repellent, OFF® Deep Woods Insect Repellent VIII, and Cutter® Skinsations Insect Repellent). Four products were more natural based without DEET (Cutter® Natural Insect Repellent, EcoSmart® Organic Insect Repellent, Cutter® Lemon Eucalyptus Insect Repellent, and Avon® Skin So Soft Bug Guard). And then three seemingly random products were tested (Avon® Skin So Soft Bath Oil, Victoria's Secret® Bombshell perfume, and Mosquito Skin Patch®)
The results: The researchers reported that all the tested mosquitoes were “strongly repelled” by products containing DEET and lemon-eucalyptus oil. For the other products, they found mixed results. And it seems the Mosquito Patch is not worth your hard earned money.
"Overall, the results from this study confirm that DEET repellents are the most effective mosquito repellents in the market,” reported the authors. “Although, based on the results from this study, a lemon-eucalyptus oil containing p-menthane-3,8-diol has similar efficacy to DEET repellents."
Strangely enough, Victoria's Secret® Bombshell perfume is also good at repelling mosquitoes. While DEET held its repellant effect for over 240 minutes, Victoria’s perfume was effective for 120 minutes-giving a lady a good reason to reapply while outdoors.
Picaridin and permethrin are also very effective and safe compounds. They were not included in the mentioned study but have been validated elsewhere. Permethrin is used to treat inanimate objects like your boots or tent.
Keep in mind that there is good data for using DEET as tick repellent also. Unfortunately we cannot apply the study’s mosquito data to ticks. As one is a true insect and the other is an arachnid (more closely related to spiders), the non-DEET products may not offer as broad coverage. I am all for “safer” and more “natural” when possible. But West Nile Virus and Lyme’s disease has kept me using DEET or Picaridin and permethrin year after year. Now the lemon-eucalyptus oil seems like a great choice also. I suppose I could also treat my tent and hiking boots with permethrin but I’m either too lazy or not sufficiently paranoid.
Sometimes it feels like we spin our wheels in medicine. As a dermatologist, I advise people to stay out of the midday sun but enjoy the mornings and evenings. Sounds like good advice right? Until you hear the CDC’s radio ad telling you exactly the opposite. In order to avoid mosquitoes, they want you going out during the midday. Blasphemy! But I’d like to propose a third option: Go out when you want and live life. Just remember your bug spray and sunscreen. And if you ever catch me in Victoria’s Secret…I am just buying my insect repellant!