How to avoid mosquito bites

In this episode of Life Kit, reporter Andee Tagle talks to entomologist Sammy Ramsey and environmental health professor Brian Byrd about why some people get bitten more than others, which ingredients to seek in bug repellents and what you can do to protect yourself against those itchy bites. Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Speaker 00

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• 0:16Marielle Segarra?

  You're listening to Life Kit from NPR. Hey, it's Marielle. We talked about ticks on the show recently. They're not my fave. But guess what? There's a little flying creature that gives them a run for their money. Let me give you a hint. You're lying in bed on a summer night, drifting off to Snooze Land, when you hear a high-pitched whining sound right next to your ear. How did this damn mosquito get into my house? Now I'm up, the lights are on, I'm on a mosquito hunt, because if I don't kill this thing before I fall asleep, it will feast on my blood all night and leave me with itchy

• 0:56Marielle Segarra?

  bites all over my body. Seriously, I've had one bite me on the eyebrow. Not the face, y'all. And those itchy, inflamed bumps can be more than just a nuisance. In rare but real instances in the US, they can lead to serious or even deadly illness. According to NASA's report on mosquito-borne diseases from May, the US has seen nearly 1,500 cases of dangue fever so far this year. They're about the same number of cases of West Nile virus in 2024.

• 1:25Speaker 02

  Out of all of the creatures on the planet, mosquitoes have caused us no end of trouble. They are likely the most devastating insects that we have ever encountered.

• 1:36Marielle Segarra?

  Sammy Ramsey is a professor of entomology at the University of Colorado Boulder. And the thing you need to know about him is he's a bug evangelist. He thinks insects are so awesome, he goes by the nickname Dr. Bugs.

• 1:49Speaker 02

  I'm going to say something that I think a lot of people will find very surprising. I, Dr. Sammy, your friendly neighborhood entomologist, think that we should eradicate mosquitoes. Hey, I said it.

• 2:02Marielle Segarra?

  Because mosquitoes are just so perfectly adapted to spread disease, he says.

• 2:08Speaker 02

  They can find a human being like a homing beacon, homing in on their breath and their body heat to arrive there, and then have this remarkable set of needles, all tucked into their face, all stitched together, that allow them to pierce the human skin so effectively that oftentimes people don't even feel that they've been bitten enough to fight back and try to slap the mosquito.

• 2:32Marielle Segarra?

  The good news is we humans have found simple, effective ways to protect ourselves from mosquitoes. So on this episode of Life Kit, reporter Andy Tagle talks all about that with Sammy and with Professor Brian Bird of Western Carolina University. They get into why some people get bitten by mosquitoes more than others, what ingredients you should look for in bug repellent, and why you've got to stop spritzing that bug spray the same way you do your perfume.

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• 4:11Speaker 04

  First thing to know upfront, takeaway one, mosquitoes aren't just a summertime or a weekend in the woods problem. Anywhere there's standing water, hot temperatures, and humans, mosquitoes are likely to follow. Is it just me, or are there a lot more of these disease spreaders, a lot more often? Or is it just in my head? You know, like here, where I live in San Diego, this isn't just a problem June through August or September anymore.

• 4:35Speaker 02

  Oh, it's not just you. The mosquitoes are seemingly everywhere, all the time. As the climate changes around us, as we get both more rainfall as a result of climate change in a lot of areas, and warmer weather, the mosquito season can persist for longer. And the rainfall is a really big part of this as well, because the only place that they can reproduce is in stagnant pools of water. And so when that water collects in tree holes after heavy rain, or discarded tires, garbage, cracks in the ground that have accumulated enough water and then have decomposing organic material in them that they can feed on, those mosquitoes are then able to lay a lot of eggs.

• 5:19Speaker 02

  And every year that they do really, really well, you have a larger number of mosquitoes emerging that spring to then start a new population.

• 5:27Speaker 04

  Okay, that doesn't make me feel good. But we don't have to worry about every mosquito that we come into contact with, right?

• 5:32Speaker 02

  Absolutely. You certainly don't have to worry about every mosquito. I mean, really, you only have to worry about half of them. The males are out for pollination. They are flying around, sipping nectar, moving pollen from flower to flower, and allowing for those flowers to set fruit and seed. Great, good for them, love that. The lady mosquitoes actually need the nutritive components of blood to really get the process of generating the egg yolk for their eggs going. And if they don't feed on our blood, it doesn't allow them to actually produce offspring, unless they have fed on the blood of another vertebrate organism.

• 6:11Speaker 04

  Now, strictly speaking, you don't even have to worry about every female mosquito.

• 6:18Speaker 04

  There are over 3,500 mosquito species in the world, but only a small percentage of those bite humans and/or carry human diseases.

• 6:28Speaker 05

  What's important, if you notice you're getting mosquito bites, it's time to do something about it.

• 6:32Speaker 04

  Brian Byrd is a medical entomologist and professor of environmental health at Western Carolina University.

• 6:38Speaker 05

  And spend most of my time studying mosquito-borne diseases.

• 6:41Speaker 04

  Brian says there are a fair number of myths and misconceptions about mosquitoes out there. He's going to help us with a few for takeaway two. While the majority of mosquito bites don't pose a serious threat, there's still something you want to avoid as best you can, especially if you're like me, someone who came to this story because you feel like you're attacked by mosquitoes 10 times more than anyone else you know, but you're wondering, is that really true? Like, are some people just more prone to getting bitten?

• 7:08Speaker 05

  It absolutely is true. And there's all kinds of sort of factors that play into that.

• 7:13Speaker 04

  One big factor is your smell.

• 7:15Speaker 05

  So they'll notice how much you're breathing off. They'll detect that CO2 and then find their way closer and closer. And as they get closer, they might even cue into things like body temperature or other odorants that we give off. We give off things like lactic acid and some humans give off trace amounts of ammonia that some mosquitoes can kind of detect. Those are two sort of important, what we call, human odorants that mosquitoes can really hone into.

• 7:42Speaker 04

  Next, clothing. A 2022 study found it's best to avoid wearing red and orange, likely because they most closely resemble skin tones. On the other side of the spectrum, mosquitoes weren't attracted to white, blue, green, and purple, something to consider before your next picnic. Another thing to keep in mind might be what you put in your picnic basket, because there's been some research to suggest certain aspects of diet can attract mosquitoes. Specifically, researchers found that your body odor after drinking beer and eating bananas was a lot more attractive to little suckers. And I also asked about blood type, something I've long heard and blamed for being extra mosquito bite prone.

• 8:26Speaker 04

  But Brian didn't bite. The science on this just isn't settled, he says.

• 8:31Speaker 05

  Regardless of your blood type, there's not one blood type that's 100% protective, right? So it's not that you're going to be at A hundred percent reduced risk for mosquito borne disease. And so I think we have other tools that would be much better ways to protect yourself than to think about your blood type.

• 8:49Speaker 04

  Fair enough, Brian. So let's talk about those best ways to protect yourself. The three Ds.

• 8:55Speaker 05

  Three Ds are some of the basic mosquito protection 101, which involves drain, dress, and defend.

• 9:02Speaker 04

  Let's learn those one by one. Takeaway three, drain. Prevent mosquito populations before they start.

• 9:08Speaker 05

  We really want to focus on standing water. And so if you're regularly emptying or cleaning out or covering containers that can hold water, these could be tires or buckets, toys, planters, bird baths, flower pots, the list sort of goes on. If you're regularly, maybe once a week, dumping that water or just doing a backyard inspection to make sure you're not creating any of your own problems when it comes to mosquitoes, that drain can actually reduce some of that risk in your backyard.

• 9:37Speaker 04

  Okay. And I'm thinking about how much water there needs to be and how, you know, how big of an area we're talking about.

• 9:44Speaker 05

  Yeah, it doesn't take much, you know, even a small sort of, you know, coffee cup that's, you know, a third of the way full in your backyard can, you know, produce a lot of mosquitoes. And it doesn't take long during the summer. You can go from eggs to adults, certainly within a week to, you know, 10 days. And so it doesn't take long and it doesn't take much.

• 10:08Speaker 04

  Next up, dress. This one's about making sure you're covered by appropriate physical barriers. Takeaway four. So if you're camping, for example.

• 10:17Speaker 02

  Making sure that your tent is very well sealed is really helpful, but I know people who camp sometimes and all they want to do is sleep in a hammock. You can bring a mosquito net to then drape over that hammock and the mosquito net will protect you. In your home, you really need to pay attention to how well your doors are screened. If you have screen doors or screens on your windows, they don't last forever.

• 10:40Speaker 04

  This also means wearing protective clothing.

• 10:42Speaker 05

  Cover your skin as much as possible. Wear clothing like long sleeve shirts and long pants that can reduce skin exposure. That's often a tough ask in the middle of the summer when mosquito biting pressure is sort of the highest. But if you have really tight-fitting, thin clothes, especially the type of clothes we like to use when we're going for a run or working out, some species can bite through that clothing. So I think if you're wearing a little looser-fitting clothes, that can add some level of protection.

• 11:09Speaker 04

  And if you're someone who works outdoors in bug or mosquito-prone areas, Brian says it might be a good idea to go one step further.

• 11:16Speaker 05

  Promethrin could be a repellent you can use to treat clothing and gear. And it's not for the skin, but you can apply it to your clothes and get, in some cases, long-lasting through multiple washes, protection against mosquito bites and ticks.

• 11:34Speaker 04

  Something to note about Promethrin, the Environmental Protection Agency evaluated it for health and safety and deemed "risks below levels of concern." But you definitely don't want to get it on your skin. Even brief exposure could cause irritation or burning on the spot. And accidentally ingesting it could cause dizziness, trouble breathing, or vomiting. Also of note, Promethrin spray is toxic to cats. So use only if needed and take care to use correctly. And that brings us to the last and seemingly most controversial D, "defend." Takeaway five: For individual defense against mosquito bites, use bug repellent. Now, after that disclaimer,

• 12:19Speaker 04

  this is something a lot of people understandably might feel concerned or confused about. Repellents often involve chemicals, and namely, one called DEET. DEET probably isn't what you're thinking it is, and we'll get into that in a second. But first, Sammy is going to explain one of the ways it's thought to work and why you want to use it. Remember in the beginning of the episode when he told us about how mosquitoes can find humans like homing beacons?

• 12:47Speaker 02

  If you think for a moment about what it is that DEET is doing for you, it provides hours and hours of consistent relief by confusing the capacity of the mosquitoes to smell you. And if they can't smell you, they can't locate you as a host. It basically camouflages your chemical scent so that you do not actually smell like a human being or a host for them.

• 13:09Speaker 04

  And there are other theories that suggest DEET confuses a mosquito's senses on approach and then repels them if they land. They probably don't like that because, fun fact, mosquitoes taste with their legs. That's why when using repellent, you want to fully cover your exposed skin.

• 13:27Speaker 02

  I've seen people just kind of spritz it like cologne, like a little bit here, a little bit there, rub it together. That's not going to help you. You want to make a sweeping motion each time you spray it so that the chemical is actually landing in very well-distributed amounts across your skin instead of piling up in one area.

• 13:45Speaker 04

  So when used correctly, bug repellents with DEET can basically act like invisibility cloaks against mosquitoes. Amazing, no? Now, let's address why you might have concerns about DEET.

• 13:58Speaker 02

  Now, DEET is something that I think I've heard from a lot of people that they're afraid of. And when I talk to them about it, they say, oh, yeah, DEET, it like thins eggshells and it's bad for pregnant women. And I realized after a while, they weren't talking about DEET, they were talking about DDT.

• 14:14Speaker 04

  Briefly, DDT, short for dichlorodiphenyletrichloroethylene, is an insecticide that was banned in the US back in the 70s. It was really effective at combating insect-borne diseases, but it was found to do a lot more harm than good. It doesn't break down easily in the environment, causes liver tumors, and is a likely human carcinogen. DDT is a completely different thing from DEET. D-E-E-T. The name DEET is a reference to the product's chemical compound, diethyltolamide. Unfortunately, DEET just sounds incredibly similar to that famously banned insecticide. And also protects against pests, but that's where

• 14:59Speaker 04

  the similarities end. DEET has been deemed safe by the EPA. Their last review, which was back in 2014, just FYI, didn't identify any risks to human health, non-target species, or the environment.

• 15:13Speaker 05

  If it's used appropriately, DEET does not provide a health risk, right? So sometimes people think, you know, a little is good, a lot is better, so they'll buy higher concentrations, for example, of DEET. And we know that even lower concentrations, like 10% DEET or 20% DEET, can last for up to about two hours or even longer. And then those higher concentrations actually last longer, it doesn't change their effectiveness.

• 15:38Speaker 04

  So before you buy, look at those labels and think about what you really need. If you're just heading to a neighbor's backyard barbecue for an hour or two, a lower concentration, like 10%, is probably the right call. But if you're, say, headed to the rainforests of Borneo on a research trip, as Sammy's done before, you'll probably want something that lasts you the day. Maybe as high as 50% DEET. The point here, not every bug spray is right for every person or scenario. The American Academy of Pediatrics, for example, says to remember, anyone under two might have skin different than that of an adult or even an older child. So, apply DEET sparingly when it comes to super young kids. But for most of us, when used correctly, it's effective and safe.

• 16:23Speaker 04

  Let's be really clear here, though. There are bug spray best practices. Don't apply in enclosed spaces or under your clothes. Just the exposed skin and outward-facing stuff. Don't spray directly on your face. Instead, spray into your hands and then rub onto your skin. Wash off your repellent with soap and water when you get back inside. And be aware, there's also certain kinds of material that DEET can interact with strangely.

• 16:52Speaker 02

  Things like spandex, nylon, rayon, it can melt them. There are plastics in eyeglasses and stuff that you also don't want to get this chemical on. It can kind of gooify them in ways that will make them look less than stellar. So do keep that in mind.

• 17:07Speaker 04

  Yikes. I mean, should... But it's okay for your skin in the smaller concentration? I mean, it just makes me feel strange that something at a higher concentration would melt a plastic, but it is okay for my skin? Or like even okay for my kid's skin? How does that work?

• 17:22Speaker 02

  I know how scary it sounds when someone says that this has the capacity to dissolve things like latex and so on. But, I mean, water has the capacity to dissolve sugars. And you can drop it on a sugar cube and be like, oh, my God, it just turned that into nothing. What will happen if I deposit this water on the surface of my skin? And because of the totally different chemistry of your skin, you're totally fine.

• 17:45Speaker 04

  If that analogy still doesn't make you feel totally comfortable with DEET products?

• 17:49Speaker 05

  The good news really is there's other products. There's Bacardin, there's IR3535, there's Oil of Lemon Eucalyptus, and others that have been proven effective.

• 18:00Speaker 04

  Brian also shared a great online tool for this from the EPA with a very direct name. Find the repellent that is right for you. It's a little dashboard that asks how long you'll be outside, what you need protection from, even if you're interested in a particular active ingredient. There are likely also a lot of products that aren't on the EPA's list that you might have questions about. When I told people that I was reporting on this story, the questions started flooding in. What about essential oils, citronella candles, those little bracelets or bug spray patches I put on my kids' clothes?

• 18:31Speaker 05

  You know, there's a lot of alternative options out there. And I think the important message is that different pathogens like viruses that can cause disease, from a public health perspective, we want strong data supporting what we're going to recommend. So if they're not evidence-based, we do not recommend them.

• 18:52Speaker 04

  Before you buy, look for the science. If a product doesn't mask your body heat or human odor entirely, don't expect it to work. Or at least, work well enough to protect you better than draining, dressing, or defending. Finally, I asked Sammy and Brian about what to do after you've been bitten. The answer? Not much. Takeaway six: less is more. So what do we do when one of these little suckers gets us?

• 19:19Speaker 02

  Oof. Calling them little suckers is the perfect way to refer to them, too. That's precisely what they are.

• 19:26Speaker 05

  The first thing I do is, you know, avoid more bites, right? So it might be putting on another layers of clothes. It might be reaching for the repellent. But if I get a mosquito bite, I'm really focused mostly on just keeping that bite clean, right? Look for signs of infection. It can be any redness or persistent swelling or pus. Especially with children, they've scratched it and introduced some bacteria into that wound.

• 19:53Speaker 02

  One thing that I do is I slap a Band-Aid over it to kind of prevent my instincts for scratching.

• 19:59Speaker 04

  And then there are topical ointments you can use, of course. Hydrocortisone is a common one. Aloe vera is a good natural idea. But a lot of people have their own go-to favorites for itch relief. I asked Sammy about a few that I'd heard, like running your arm under hot water, slapping the area so the pain could substitute the itchiness, or even applying things like oatmeal or honey. Those last two are both safe remedies, according to the Cleveland Clinic, but it might not be recommended if you want to avoid more bug bites.

• 20:27Speaker 02

  There are a lot of things that you can do. Putting ice on it, if you're someone who is particularly prone to swelling or heavy reactions from mosquito bites. Not everyone reacts the same way. It's not actually the bite of the mosquito that causes your skin to turn red and swell. It's actually the saliva that they've injected, and it's the response of your immune system. There's not a lot that you can do about your immune system's response other than slowing it down.

• 20:53Speaker 04

  And when is it time to see someone about a potentially more serious disease contracted from a mosquito?

• 20:57Speaker 02

  There is no one answer to when you should be worried that you have a disease from mosquitoes because they are such effective vectors that there are so many different diseases that they are able to spread to people. And all of them have their own sets of ailments and symptoms and so on. I will say that a lot of them have very generalized symptoms.

• 21:20Speaker 05

  Body aches, joint aches, confusion, vomiting, any neurological symptoms seek health care. You don't want to wait.

• 21:28Speaker 02

  You know your body probably better than anybody else. It's worth going to a doctor and having that examined to determine if there is a problem there and really make sure to describe the set of circumstances. I was in Thailand for a vacation and coming back and I'm just feeling kind of crummy. And I was bitten by some insects there. I'm not entirely sure, but that might be related to this. That can be really helpful for your physician.

• 21:56Speaker 04

  Before we recap, a quick note. A previous version of this story had unclear language about how DEET may work to repel mosquitoes as well as its effectiveness. So we've added additional context to illustrate that DEET may work to repel mosquitoes in a number of different ways. Also, the concentration you use to repel mosquitoes corresponds to how long it will protect you, not how effective it is. Okay, let's recap. Takeaway one, you're likely to find mosquitoes just about anywhere you can find, hot temperatures, standing water, and humans. They're not simply a summertime or out in the woods type pest. So, takeaway two, try to avoid being bitten in the first place.

• 22:37Speaker 04

  The best way to do that is, takeaway three, drain, dress, and defend. Start by draining standing water once a week to eliminate any potential mosquito breeding grounds nearby. Takeaway four, dress to protect yourself. Create physical barriers between you and mosquitoes by wearing loose-fitting clothes when you go outside. Use screen doors and mosquito nets when you can. And fans and AC units can help guard from mosquitoes, too. Takeaway five, defend your exposed skin with bug repellent. DEET is safe and effective and the preferred choice of our experts. But there are other options and different concentrations that will work best depending on your personal needs. Finally, takeaway six, when you get a mosquito bite, less is more.

• 23:20Speaker 04

  Keep it clean and dry, do your best not to scratch, and monitor for infection. If you feel strange or feverish after getting bitten, especially if you traveled outside the country, don't wait, consult your doctor.

• 23:33Marielle Segarra?

  That was Life Kit reporter Andy Tagle. For more Life Kit, check out our other episodes. We have one on composting and another on protecting yourself from ticks. You can find those at npr.org/lifekit. And if you love Life Kit and want even more, subscribe to our newsletter at npr.org/lifekitnewsletter. This episode of Life Kit was produced by Sylvie Douglas. Our visuals editor is Beck Harlan, and our digital editor is Malika Gharib. Megan Cain is our senior supervising editor, and Beth Donovan is our executive producer. Our production team also includes Claire Marie Schneider and Margaret Serino. Engineering support comes from Simon Laslow-Janson and Tiffany Vera Castro. I'm Marielle Segarra. Thanks for listening.