Health

Socks may keep mosquitoes at bay

By The World ⋅ December 8, 2010 ⋅ Post a comment
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Old socks may be used to keep mosquitoes at bay (Photo: Noodle Snacks)

Do you have a mosquito story? Tell us about it here

A new scientific study suggests smelly socks could help in the fight against malaria. The odors could be used to attract mosquitoes into traps. Anchor Lisa Mullins speaks with the lead author of the study, Dr. Renate Smallegange in the Netherlands. Download MP3

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The text below is a phonetic transcript of a radio story broadcast by PRI’s THE WORLD. It has been created on deadline by a contractor for PRI. The transcript is included here to facilitate internet searches for audio content. Please report any transcribing errors to theworld@pri.org. This transcript may not be in its final form, and it may be updated. Please be aware that the authoritative record of material distributed by PRI’s THE WORLD is the program audio.

Lisa Mullins: Sharks kill a handful of people every year, but they get a lot more press than arguably one of the biggest killers in the natural world, mosquitoes.  Mosquitoes don’t kill you with a simple bit.  Their bit can transmit malaria though and that’s a disease that afflicts millions of people every year. Scientists have found that mosquitoes find their prey by sniffing out the carbon dioxide that all vertebrae animals breathe out.  So CO2 can be used to attract the insects into a trap. A new study suggests — this one was peer reviewed by the Malaria Journal — it says there’s something else that mosquitoes cannot resist.  Renate Smallengange of the Wageningen University in Netherlands led the study.

Renate Smallengange: We also added human body odor and the way we collected that was by wearing socks just off the feet, because we know that those odors are very attractive for the specific mosquito species that we were interested in.

Mullins: Okay, give us the breakdown.  You tried this experiment with clean socks.  You tried the experiment with just carbon dioxide from yeast, is that correct?  And then you tried with all the components of a smelly human foot that you’ve been describing.  So give us the success rate of each of those.

Smallengange: Well, a clean sock is not attractive at all.

Mullins: To the mosquitoes.

Smallengange: To the mosquitoes, yes.  The smelly socks are very attractive, but when you add the carbon dioxide you augment the attractiveness of smelly socks.  So I don’t know it by heart, but apparently that’s about 45-75% that you can catch of the mosquitoes that we released in our experiment.

Mullins: 75% using all the elements included in this smelly sock that had been worn by a human for how long?

Smallengange: During one day.  That’s quite enough.

Mullins: A full day.  How did this occur to anybody to use a smelly sock to attract mosquitoes?

Smallengange: Well, it was a former colleague of mine who noticed that if you are standing straight up that this African malaria mosquito it goes to the feet.  So apparently the feet are really attractive, although it also has to do something with the compression, infection of odors.  So after that we decided well, why don’t we try worn socks.  And we noticed that they are highly attractive, and they stay attractive for a long time as well. So that for us was a convenient way to introduce body odors in our experimental setup because you don’t want to use a full human being for all your experiments.

Mullins: Now, this is for this particular kind of mosquito.  Do you know if this would apply to mosquitoes that we have here in the United States?  Of course, we don’t have the same problem with malaria, but is this applicable here?

Smallengange: Well, all mosquitoes are attracted to carbon dioxide, but not all mosquitoes are attracted to human body odor.  So it depends on the species whether it will be attracted to the human body odor or not.  So yeah, I think it’s worth a try.

Mullins: So, if the idea in Africa is to find a cheaper mosquito trap for African villagers, how many socks are you gonna need per year to keep one of these traps working?

Smallengange: I have no idea and that’s also not our intention, to use the socks in Africa.  What we want to use eventually is to use the scent mixture that we’re still improving, so it will be highly attractive and can be used in a convenient way; so it’s the same mixture you can use every night to attract these mosquitoes.

Mullins: All right.  Dr. Renate Smallengange, thank you very much.  Nice to speak with you.

Smallengange: You’re welcome.

Mullins: Dr. Smallengange lead a study to improve mosquito traps using socks that stink.  Now, if you have a good mosquito story or more likely a bad mosquito story, especially if you have your own perfectly safe recipe for mosquito control, share it with us.  Just go to theworld.org and post your story in the comment section.


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Discussion

17 comments for “Socks may keep mosquitoes at bay”

  • http://www.theworld.org The World

    We’d love to hear your mosquito story. Share it with us in the comments below.

    • Peggy

      One summer I worked as a white water rafting guide in Utah and Arizona and boy were the mosquitoes out of control among the tamarask when we camped along the river each night. I seemed to be the particular target for those mosquitoes, sometimes earning me the “privilege” of sitting in a screened tent instead of fixing dinner for our passengers, they were so swarmed around me. (Now I know I should have just needed to change socks!) But after trying every mosquito repellent known to man, including military level DEET that burned a whole through our plastic table cloths, I tried one product known to WOMAN–Skin So Soft by Avon. It worked! I didn’t know why, but now I do. It must have perfumed away that body odor!

  • Nancy Moynihan

    My Mosquito Story

    In 1987 I arrived in India where I quickly ended up out the boonies in a very small village with a ruptured disc in my back and stuck in bed due to pain. My second night I awoke very sick, convinced I had malaria. I was awake, afraid and sick all night, half way around the world where I knew no one and was incapacitated by pain. It was quite a pickle I was in. The next morning I stopped the first person who came near me and asked “how many mosquito bites does it take to get malaria?” and was completely shocked when the person answered “one! It only takes one of those things to knock you to your knees!” In that moment I suddenly realized how powerful that bug is compared to all that humans are capable of. It turned out that I did not have malaria. I did however, develop a healthy respect for the power of nature under third world conditions.
    Fortunately, I never did get malaria the whole time I was there.

    Nancy Moynihan
    Atlanta

  • http://www.wetlandsid.com David Sperduto

    The conventional wisdom is to remove from your yard any containers which might collect rainwater and thus breed mosquitoes. However, I place as many empty containers as I can find around the yard in warm weather. These do indeed collect rainwater and provide many little pools for mosquitoes to lay their eggs. These eggs develop into young larvae within a week. But I empty these containers every 7 days or less, thereby dooming the young larvae to dry out on the ground. My containers serve as a series of mosquito traps, ultimately destroying larvae that otherwise might have developed into adults if the adult female mosquito had laid them in a swamp or unattended container of water.

  • Mel

    This news is hardly new to me and many others who live in mosquito infested regions. Just last week I retrieved my socks from where I left them outdoors and I had to shake off the mosquitoes. In addition, I have read elsewhere on more than one occasion that mosquitoes are attracted to a combination of CO2 and your body order. In addition, the scent of some people is more far more attractive to mosquitoes than others, not to forget some animals. If these scientists in your interview just discovered this information, then they have been incredibly ignorant of what many others have been aware of for a very long time. The key challenge is to cheaply build mosquito traps that utilize that scent.

  • http://www.exploration.vanderbilt.edu David Salisbury

    Mosquito researchers at Wageningen are collaborating with scientists at Vanderbilt, Yale and several African research centers on a Gates Foundation Grand Challenges grant to come up with better ways to reduce the spread of malaria by interfering with the Anopheles mosquito’s sense of smell. This goes far beyond using stinky socks. For more information go to http://www.vanderbilt.edu/exploration/stories/gcgh.html. Most recently the researchers have discovered that the mosquito has a second entire set of odor receptors that it uses for tracking prey. See http://www.vanderbilt.edu/exploration/stories/agir.html.

  • Ed Lagniappe

    The “smell” of dirty socks is due to the bacteria common on human feet … which is the SAME bacteria that is used to make Limburger Cheese (Brevibacterium linens). And that cheese has been used as bait for mosquito traps. I use it to bait my mosquito traps in Louisiana. Well … I only use the parts that I don’t eat first :-)

    In 2006 a study showing that the malaria mosquito (Anopheles gambiae) is attracted equally to the smell of Limburger and to the smell of human feet earned the Ig Nobel Prize in the area of biology.[3][4]
    #3 Ig Nobel Prize list of past winners
    #4 Knols BG (November 1996). “On human odour, malaria mosquitoes, and Limburger”. Lancet 348 (9037): 1322. doi:10.1016/S0140-6736(05)65812-6
    . PMID 8909415

  • http://MozillaFirefox Laura Barmettler

    I took the anti-tumor drug Tamoxifin (?spelling) for ten years. Was never bitten by a mosquito. When I stopped the drug, here came the mosquitos.

  • http://bit.ly/eFc2ec Shriram

    There is also similar invention from india. solar mosquito trapper-cum-destroyer called Hawker, invented by Mathews K Mathews. His mission is to create a mosquito-free environment in the most innovative and cost-effective manner
    Check the link http://bit.ly/eFc2ec

  • Doug Hamblett

    About 40 years ago I stayed with a friend at his family’s summer cabin one night on Block Island [Long Island, NY]. The area was wooded and damp, and full of mosquitoes, especially that very humid July night. There was a steady light southerly breeze, but not strong enough to discourage the mosquitoes. We slept on the screened porch, screened on 3 sides. We couldn’t get rid of all the ‘skeeters before going bed. I chose the bunk alongside the lee side screen where the air would be exiting the porch. Sure enough, because my odors and exhalations were passing directly through the screen, I slept fairly well that night. My poor buddy was cursing and slapping most of the night, because his emanations drifted into the center of the room.

  • BETSY MOORE

    To avoid mosquito bites I start taking a good B vitamin complex in May and I continue until Mosquito time is over.

  • http://www.mitholdingsinc.com/divisions/provector A.L. Von Borsthaven

    As much as stinky feet make for an “appealing” story, I believe there is a better developed solution that has had little to no media exposure, and has been virtually ignored by the Gates Foundation. Tom Kollar has been working for about 10yrs to find an economical, environmentally safe, and effective solution to the mosquito problem. He developed a new version of the biopesticide Bt, a bacterium fatal to mosquitos. According to the EPA, these bacteria are non-toxic.

    The bacteria are combined with artificial nectar and proprietary attractants. The mixture is placed under a fine wire mesh, which only allows access to the mosquito’s proboscis. The mesh is placed at the center of an artificial flower that uses specific colors to attract different mosquito species. Each home uses one flower, which has a combinatorial effect as the number of homes increases. Each flower protects about 7 people around the clock, while a net would only protect 1 person at night (although ProVector LLC recommends simultaneous use of nets or other measures). The efficacy was proven by multiple field trials around the world, including independent testing by the Walter Reed Army Institute of Overseas Research.

    http://inventorspot.com/articles/tom_kollars_invention_may_save_millions_lives_provector_bt_25653

    http://www.mitholdingsinc.com/divisions/provector

    As a matter of disclosure, I have no ties to this company whatever. It just looks like a good idea!

  • steve radez

    In your interview this question was not asked? What is the downside? In other words,hypothetically if we could rid the world of mosquitoes, what would be the effect on the eco-system? Obviously, that isn’t going to happen, but, the idea here is to reduce the mosquito population. Therefore we will approach the disadvantage stages of that action – there must be a lot of them. Mosquitoes have to be good for something? I don’t feel like researching it and I thought maybe someone has

    • Earl Hatleberg

      Bats. Flycatchers and other types of birds? What else?

  • Pat

    While staying in Kruger Park, SA – I started drinking gin and tonic for some obscure reason as I am not normally a drinker…Our South African friends said this was curious because the quinine in the gin (or the tonic can’t remember which,)is supposed to ward off mosquitos – So, “Gin and It” became my adopted tipple for the whole vacation in the Upper Transvaal…

  • Patricia Cloutier

    In the 1950s I was a carhop; we had to wear skirts, not pants. Each night I had to get the new mosquito bites bleeding before I could get to sleep. One morning I counted the bites: right leg, 250, left leg, 200.

  • RangerRog

    The summer hatch of mosquitos and black flys in Maine can be quite a bloodbath. After 50+ years of cruising timber, fishing, camping, hiking and guiding you’d think I’d have some secret figured out. Never tried clean socks so I’ll talk to my wife about that, as she has given up on me on that. I know the research says CO2 attracts, so some of that reduced mindful breathing might lower the CO2, or better yet just stop breathing.

    DEET, it’ll repel mosquitos while your skin is having a meltdown. In one day that stuff dissolved a plastic pencil I was using for tallying trees and field notes out in the forest. Ye’ old Scripto lead pencil melt down, RIP! I still remember that hot day, I think we needed that Gin-up remedy posted from another PRI fan.

    Seriously, what works best for me is a long sleeve cotton T-shirt, or a canvas short over a T-shirt. You sweat lots but the mosquitos can’t drill through both layers. Those bug-shirts work, but the repellent wears off. A T-shirt with a really light weight breathable shell works fine too.

    Make like the horses do, switching a big bandanna or fern frond around your head or shoulder will dust’em off… A dose of that Zen-like we are one – peaceful easy with these bloody flying bloodsuckers might help. If you let your attitude get wore down by the blighters and you will be a mosquito goner for sure.