Photo by James Jordan on Flickr.
In last week’s Sunday Links I posted an article on a new study that has shown there is “evidence for inhibition of cholinesterases in insect and mammalian nervous systems by the insect repellent deet“, or in normal-speak, “DEET is like, uh, bad for you eh”.
The abstract for the study and full 28 page .pdf are available here.
After reading that post @VancityAllie commented:
“Aaah, that’s pretty scary about DEET. I don’t use it very often (I also use a Citronella spray)… but I HATE mosquitoes and use it enough for me to look twice at that article.
Hey I was thinking, maybe you could do an article on safe bug repellent… how to keep the bugs away without poisoning yourself?”
And this is a good point. Aside from being annoying, bugs like ticks and mosquitoes can carry disease, so its not a bad idea to repel them. At the same time, we want to make sure the chemicals we are putting on ourselves are safe and don’t bare any long-term side effects. So lo and behold, I’ve done some research (and as usual, by ‘research’ I mean I hastily Googled some stuff) to get some more information on what options we have to keep those pesky bugs away. Some of the info on DEET was pretty alarming.
You’ll often hear people saying DEET is the best bug repellent, and swear by its effectiveness. So what exactly is DEET? From Wikipedia:
“N,N-Diethyl-meta-toluamide, abbreviated DEET, is a slightly yellow oil. It is the most common active ingredient in insect repellents. It is intended to be applied to the skin or to clothing, and is primarily used to repel mosquitoes. In particular, DEET protects against tick bites (preventing several rickettsioses, tick-borne meningoencephalitis and other tick-borne diseases) and mosquito bites (which can transmit dengue fever, West Nile virus, Eastern Equine Encephalitis, and malaria).”
Effects on health
As a precaution, manufacturers advise that DEET products should not be used under clothing or on damaged skin, and that preparations be washed off after they are no longer needed or between applications. DEET can act as an irritant; in rare cases, it may cause skin reactions.
In the DEET Reregistration Eligibility Decision (RED), the United States Environmental Protection Agency (EPA) reported 14 to 46 cases of potential DEET-associated seizures, including 4 deaths. The EPA states: “… it does appear that some cases are likely related to DEET toxicity,” but observed that with 30% of the US population using DEET, the likely seizure rate is only about one per 100 million users.
The Pesticide Information Project of Cooperative Extension Offices of Cornell University states that “Everglades National Park employees having extensive Deet exposure were more likely to have insomnia, mood disturbances and impaired cognitive function than were lesser exposed co-workers”.
Recently, DEET has been found to inhibit the activity of a central nervous system enzyme, acetylcholinesterase, in both insects and mammals. This enzyme is involved in the hydrolysis of the neurotransmitter acetylcholine, thus playing a role in the function of the neurons which control muscles. Because of this property, many insecticides are used to block acetylcholinesterase, which leads to an excessive accumulation of acetylcholine at the synaptic cleft, causing neuromuscular paralysis and death by asphyxiation. DEET is commonly used in combination with insecticides and has the capacity to strengthen the toxicity of carbamates, a class of insecticides known to block acetylcholinesterase. These findings bring evidence that, besides having known toxic effects on the olfactory system, DEET also acts on the brain of both insects and mammals, and that its toxicity is strengthened in combination with other insecticides.
Effects on materials
DEET is an effective solvent, and may dissolve (part of) some plastics, rayon, spandex, other synthetic fabrics, leather, and painted or varnished surfaces including nailpolish.
Effects on the environment
Although few studies have been conducted to assess possible effects on the environment, DEET is a moderate chemical pesticide and may not be suitable for use in and around water sources.Though DEET is not expected to bioaccumulate, it has been found to have a slight toxicity for coldwater fish such as the rainbow trout and the tilapia, and it has also been shown to be toxic for some species of freshwater zooplankton. DEET has been detected at low concentrations in waterbodies as a result of production and use, such as in the Mississippi River and its tributaries, where a 1991 study detected levels varying from 5 to 201 ng/L.
So while it seems DEET is linked to a lot of health (and environmental) issues, there is a new BBC article I saw in the latest Wanderung newsletter that takes a more balanced stance, saying “the incidence of exposures resulting in neurotoxic effects is very low, when considered in the context of the millions of people around the world who have used insect repellents containing deet”.
So, as usual, it seems to boil down to – There are linkages to health issues, potentially, but we need more research. In the mean time just limit exposure but small doses are fine – But when something can dissolve “(part of) some plastics”, that’s usually when I decide not to put it on my skin. But hey, that’s just me.
So if we don’t want to take the risk, what other options do we have?
Toxicity Category Levels
Category I = very highly or highly toxic
Category II = moderately toxic
Category III = slightly toxic
Category IV = practically non-toxic
(for reference DEET is Category III for eye, dermal and oral)
- Citronella Oil has been used for decades and is non-toxic. A popular alternative, but less effective, and may even attract bears. (Thanks again to Wanderung.ca for that tid-bit).
- Picaridin, a chemical developed by Bayer, is supposedly as effective as DEET, and maybe even more. I wasn’t able to find much on it regarding health issues. A 2005 report by EPA doesn’t show any serious health threats, but I’m sure something will come out in the future once it is studied more. It is Toxicity Category III for acute oral and dermal, and category IV for primary eye and skin.
- Eucalyptus-based repellents are considered effective against mosquitoes. Eucalyptus is an essential oil, but can actually be toxic in large quantities (which made me ask if koalas were aware of this, but apparently they are tolerant to it, phew!). Toxicity Category IV for acute oral, dermal and skin irritation, and Category II for eye irritation.
- Mud bath – Seems to work for elephants, just sayin’.
So I guess there’s a lot more to repelling bugs than I would have ever thought. If only I could repel bugs the same why I repel women, it would all be so simple. In conclusion to my extensive 1 year, er 1 hour, er ok 15 minutes of research, here’s what I would recommend:
Don’t use any repellent containing DEET unless you are going to be in an area with a lot of mosquitoes and/ or ticks. They can carry some nasty things you really don’t want. If you’re out in the backyard having a barbeque, and don’t want a few annoying suckers landing on you, I’d go with one of the plant-based alternatives. I personally would never spray any DEET on kids or pregnant women either (not that I go around randomly spraying insect repellent on people).
Hope that was useful.
David @I Luv Neem Products
Hi! I’m with Candace above on Neem-based bug repellents. I’m now in my mid-30s and have been carrying around the same stinking bottle of deet bug dope since I was a kid at summer camp! Even when i was little i knew it wasn’t good for my skin. It just seemed like poison! Anyways, i now buy pure neem oil and put about 10 drops in 16 oz water and shake vigorously. I have used this on my skin and have had great luck keeping the bugs away. Thanks, David :-)
.-= David @I Luv Neem Products´s last blog ..Neem Toothpaste =-.
candace
www [dot] burtsbees.ca/product-line/outdoor/herbal-insect-repellent [dot] html
This bug blend is good
Karl Woll
Tyler – I was just at MEC (North Van) and they carry 1 brand of Citronella, and 2 brands of DEET stuff. (Although the Citronella was sold out and I needed it, doh!)
.-= Karl W´s last blog ..Sunday Links =-.
Sam
One of the tricks I’ve tried myself is lime. Cut up a lime and then rub it on any exposed skin. It’s a little sticky and pulpy, but it smells good and is a lot cheaper and healthier than any of the deet-laden bug sprays.
One suggestion that my mom told me that I have yet to try is Listerine. Put it in a spray bottle and spritz onto skin, or spray/pour around the perimeter of where you’re sitting. Considering you can get a 1L bottle of the generic stuff for only a few bucks it’ll definitely be something I’ll try on my next trip. I’ll be sure to post the results!
And of course a big campfire always helps to keep the pests at bay.
Tawcan
You can get non-DEET stuff at MEC but they don’t work all that great when it’s super buggy out. But then nothing really works when it’s that buggy out… not even 98% DEET stuff.
.-= Tawcan´s last blog ..Trip from hell – update =-.
Karl Woll
Allie – Modifying the diet is a new one to me, I’ll have to look into that.
Tawcan – Yeah, good point on the clothing as well. And DEFINITELY don’t want DEET dissolving climbing gear!
Tyler – Yes the citronella can attract bears, there is a bearsmart.ca link in the post explaining. I’m not sure if you can get alternative products at MEC, I’ll do some homework and let you know. As Candace says, your local health food store may be a good place to check.
Candace – I should have known my wonderful girlfriend would have the info on all the natural alternatives! Great info babe
So great job guys, it basically looks like a missed a bunch of stuff! I’ll take these points, doing a little more ‘research’ and do another post down the road.
Tyler
So are good places to get these alternatives to products containing DEET etc? Would something like MEC carry such alternatives?
candace
Knowing about how TOXIC DEET is I have some natural alternative suggestions,
(besides citronella) aka lemon-aid
Lemon and Eucalyptus oil -can give shorter acting natural option proven to be just as effective as the leading chemical substances-it protects against mosquitoes for two hours before reapplication is needed.
Catnip cure-recent studies found that the oil extracted from the perennial herb (Nepeta cataria), member of the mint family, repels mosquitoes better than the compound used in most commercial repellents.
Neem oil-a natural vegetable oil, neem oil is extracted from the Azadirachta indica tree. The leaves, seeds, and seed oil of the neem contain sallanin, a compound that has strong mosquito-repelling properties.
Now a combination catnip and neem oil really does the trick. as it is not recommended to apply pure oil directly on your skin -there are blends available at your local health food store.
Scores of other plants have been tested as possible insect repellents, including cedar, verbena, geranium, lavender, pine, cinnamon, rosemary, basil, thyme, allspice, garlic, and peppermint. Some products combine two or more of such botanicals to drive away arthropods. One such blend, for instance, contains oils of citronella, cedar, peppermint, lemongrass and geranium encapsulated in bees wax. According to a 2003 study by the Uni of Guelph, the product provided 100% protection for two hours and more than 85% for over three hours.
Non topical solutions-Some products come with a butane cartridge that heats a repellent mat, whish releases allethrin, a copy of naturally occuring insecticide. The cell can cover an area of 225 square feet for up to four hours per mat. This type of mosquito repellent is used by the US army in Iraq, Kuwait, and Afghanistan.
Long comment but hope this helps anyone looking for alternatives when enjoying the great outdoors :)
Tyler
I’ve always used DEET based sprays. Just found them more effective I guess. lol
As for hanging out in the backyard, I dont use spray, just not enough mosquitoes to bother me. As for being outside, yes DEET is nice for mosquitoes (if you put aside the plastic eating, poison parts) though it doesn’t stay away the flies as effectively.
I’ve been told/read that Citronella is a bear attractant and why you shouldn’t use it when camping in bear territory, though tell me if I am wrong. At home I like the mosquito coils or the candles for bugs anyway.
When I worked for LD, our shipper/receiver lady used to make her own bug repellent and if i remember, it was good and warding off mosquitoes, black flies and others. She made it at home with off the shelve stuff, forget what though.
Perhaps we should do a test in our woods/backcountry. DEET, Citronella, and whatever other sprays we can find and see who comes back least bit!
Tawcan
And that’s why you get a bug net and anti-bug clothes (aka nylon). Frankly if you wonder off to BC backcountry in the summer time mots of the time DEET bug spray will do you no good. It’s not just mosquitoes we’re talking about here, there are other bugs like horseflies attacking you too. And horseflies can literally take chunks out of your flush.
Just elaborate what Allie said about diet… from personal experience I found banana attracts bugs, so I try not to have banana 1 or 2 days before any trips to the backcountry.
Karl you already mentioned this in the post but another reason not to use DEET based spray (or any spray at all), is that DEET eats into plastic. You certainly don’t want your camping gear to dissolve on their own, especially your climbing gear!!! One time I was teaching some newbies how to climb in Smokes Bluffs. There was maybe one or two mosquitoes flying around in the area. These two female students (not very outdoor type) was horrified and proceeded covering themselves in bug spray. I watched in horror as they sprayed their entire body while wearing a harness. Luckily they weren’t on my rope. I basically told them that they should stop climbing for the day b/c they will damage all the climbing gear.
.-= Tawcan´s last blog ..Trip from hell – update =-.
VancityAllie
Hahaha! Great article. Not to mention well-written, and funny!
I think I’ll be sticking to Citronella (spray-on) from now on… it smells better, anyhow ;)
When camping, I use citronella candles and those mosquito repellent fire sticks, but those are actually toxic as well.
I’ve heard that you can modify your diet so you are less appealing to mosquitoes..
.-= VancityAllie´s last blog ..THINGS I LOVE ABOUT SUMMER =-.