A field guide to the mosquitoes and ticks that hunt people: which ones spread which diseases, where they live, when they bite, how they find you, and how the repellent options actually compare. Print it, screenshot it, send it to your sister who hikes.
Every fact below is sourced to the CDC or the EPA · no number on this page comes from us · sources listed in full at the bottom
Seven carriers worth recognizing. Each card is the same kind of summary a public-health office would post on a wall: what it carries, when it bites, where it lives, and when it is busiest. Disease lists are the ones the CDC names for each genus.
Mosquitoes
Aedes aegypti & Aedes albopictus
Aggressive, low-flying, and fond of ankles. They breed in tiny amounts of standing water, a bottle cap is enough. Source: CDC, About Mosquitoes
Culex species
West Nile is the leading cause of mosquito-borne disease in the continental U.S. About 8 in 10 infected people feel nothing; roughly 1 in 150 develop serious illness. Source: CDC, West Nile Virus
Anopheles species
Malaria is rare inside the U.S. today but remains one of the most serious risks for travelers. Check your destination before you go. Source: CDC, Malaria
Ticks
Ixodes scapularis & Ixodes pacificus
The U.S. records about 476,000 Lyme diagnoses a year. A tick usually has to stay attached 36 to 48 hours before it can pass the Lyme bacteria, so a same-day check matters. Source: CDC, Lyme Disease
Amblyomma americanum
The single white dot is on the female. Its bite can set off alpha-gal syndrome, a lasting allergy to red meat. Source: CDC, Lone Star Tick
Dermacentor variabilis
Rocky Mountain spotted fever moves fast and can be fatal without prompt antibiotics. Early treatment is the whole game. Source: CDC, Rocky Mountain Spotted Fever
Ixodes ricinus
Headed to forested or rural Europe? Tick-borne encephalitis has a vaccine worth asking a travel clinic about. Source: CDC Travelers' Health · ECDC
Specimen photographs via Wikimedia Commons. Aedes, Anopheles and lone star tick: CDC / James Gathany. Deer tick: Scott Bauer, USDA. Culex: Alvesgaspar (CC BY-SA 3.0). American dog tick: Sam Droege (CC BY 2.0). Castor bean tick: W.alter (CC BY-SA 4.0).
This is not the bug problem your parents had. The range keeps moving.
Tick-borne disease in the United States has more than doubled over the last two decades. Milder winters and longer warm seasons let ticks survive farther north and stay active more of the year, so the blacklegged ticks that carry Lyme keep turning up in counties that never used to report them.
The numbers behind that line: the CDC estimates about 476,000 Americans are diagnosed and treated for Lyme disease every year. Babesiosis, a malaria-like infection from the same tick, climbed roughly nine percent a year between 2015 and 2022. And in 2026 the CDC flagged emergency-room visits for tick bites running higher than usual for the season.
Mosquitoes are moving too. The Asian tiger mosquito, an aggressive daytime biter that can carry dengue and Zika, is projected to find suitable habitat across far more of the northeastern United States as it warms: from roughly five percent of the region's land today toward an estimated sixteen percent by 2035.
None of this is a reason to stay inside. It is a reason to wear something that actually works, every time you go out, without having to think about it. That is what Longsleeve is for.
Four cues, in roughly the order a mosquito uses them.
Carbon dioxide. Every breath you let out is a flare. Mosquitoes track CO2 plumes from a distance; a tick waiting on a blade of grass reads the CO2 of an animal passing by.
Body heat and moisture. Warm, slightly damp skin in the 34 to 37 C range reads as "host." Cooler surfaces nearby get ignored.
Sweat and skin chemistry. Lactic acid, ammonia, and other compounds in sweat tell a mosquito you are an animal, not a rock. This is why exercise and warm evenings draw more bites.
Then contact. Ticks can't fly or jump. They wait with their front legs out, a behavior the CDC calls questing, and grab whatever brushes past. Mosquitoes close the last stretch by sight and land.
"Ticks find their hosts by detecting animals' breath and body odors, or by sensing body heat, moisture, and vibrations." CDC, Preventing Tick Bites. Mosquitoes use the same cues plus carbon dioxide and vision.
Picaridin works on the front end of that chain. It sits on the surface of your skin and jams the odorant receptors the insect uses to read those cues. The CO2 is still in the air and your skin is still warm; they just can't follow the trail to you. Nothing is killed. They land, find nothing worth biting, and drift off.
Longsleeve is 20% picaridin, EPA-registered for up to 14 hours against mosquitoes and ticks. EPA Reg. No. 101457-1. That is a registered duration claim with efficacy data on file, not a number off a marketing deck.
All four are real choices on a drugstore shelf. The CDC lists EPA-registered repellents as the ones with evidence behind them. Durations vary with concentration, sweat, and heat, so these are typical ranges from the EPA and CDC, not guarantees. No brand names, because the active ingredient is what does the work.
| Active ingredient | Typical protection | Smell | Won’t damage gear & plastics | Youngest age (CDC) |
|---|---|---|---|---|
| Picaridin (20%) | Up to 14 hours vs mosquitoes and ticks | None | Yes. No effect on plastics or synthetics | CDC guidance: 2 months |
| DEET | Up to about 10 hours at higher concentrations | Noticeable; varies by concentration | No. Labels caution it can damage plastics, vinyl, and some synthetics | CDC guidance: 2 months |
| Oil of lemon eucalyptus / PMD | Up to about 6 hours | Strong lemon-eucalyptus scent | Yes | Not for children under 3 years |
| Citronella (oil) | Up to about 2 hours, frequent reapplication | Strong citrus scent | Yes | Follow product label |
The CDC recommends EPA-registered repellents with one of these actives: DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), para-menthane-diol (PMD), or 2-undecanone. Plant oils like citronella are not reviewed by the EPA for efficacy the way registered actives are, so the duration on the bottle has less data behind it. Sources: EPA, Skin-Applied Repellent Ingredients · CDC, Avoid Bug Bites · AAP, repellent guidance for children
The active in the top row is the one Longsleeve uses: 20% picaridin, fragrance-free, all nine ingredients disclosed. See the tube →
Repellent is step one. These are the rest, straight from the CDC.
After you're outdoors, check the whole body, especially the warm hidden spots: scalp, behind the ears, armpits, belly button, waistband, groin, and behind the knees. Shower within two hours. Tumble-dry your clothes on high heat for 10 minutes to kill any stowaways.
Source: CDC, Preventing Tick BitesFine-tipped tweezers, grab as close to the skin as you can, and pull straight up with steady pressure. Don't twist, don't use a match, don't paint it with anything. Clean the bite, and watch for rash or fever over the next few weeks.
Source: CDC, Tick RemovalSweat, swimming, and towel-drying all take repellent off early. Follow the reapplication window on the label, and go sooner if you've been working hard or got soaked. A long-duration active means fewer reapplications, not zero.
Source: EPA, repellent label usePut sunscreen on, let it set, then apply repellent over it. Skip the 2-in-1 sunscreen-and-repellent products: you need to reapply sunscreen often and repellent rarely, so combining them works against both.
Source: CDC, Sunscreen and Insect RepellentBefore a trip, check CDC Travelers' Health for your destination's mosquito-borne risk. Treat clothing and gear with 0.5% permethrin, which goes on fabric and never on skin, and pack a repellent that won't melt your sunglasses or watch on the way.
Source: CDC, Avoid Bug Bites While TravelingAedes mosquitoes breed in a bottle cap of water. Once a week, empty or scrub anything that holds rain near where you live: planters, buckets, gutters, kiddie pools, pet bowls. Fewer breeding sites means fewer mosquitoes to repel.
Source: CDC, Mosquito Control at HomeThe stuff that makes you the one who always gets bitten.
A mosquito can smell the carbon dioxide you exhale from up to about 50 meters off. Bigger bodies and harder breathing put out more of it, which is part of why people who are larger, pregnant, or mid-workout tend to get bitten more.
Source: CDC, Mosquitoes and how they find hostsOnce it locks onto your CO2, a mosquito switches to eyesight. Dark colors that stand out against the sky, like black, red, and navy, read as a target. Light clothing makes you harder to pick out.
Source: published mosquito host-seeking researchMosquito heat sensors are tuned to roughly 34 to 37 degrees Celsius, the surface temperature of bare human skin. CO2 gets their attention, heat confirms the target, and they commit.
Source: published thermal-targeting researchSome studies report people with Type O blood get bitten more than other types. Mosquitoes appear to read chemical markers many people secrete through their skin, which may matter more than the blood type itself.
Source: peer-reviewed blood-type preference studiesSwat at a mosquito and it can link your scent to the near miss in about 15 minutes, then steer clear of you for hours. Your hand is, briefly, a repellent. Actual repellent lasts longer.
Source: research on mosquito learning and aversionMoving air cuts mosquito landings by roughly 45 to 60 percent. They are weak fliers, and a breeze both pushes them off course and scatters the CO2 plume they follow. A strong fan on the porch genuinely helps.
Source: field studies on airflow and landing ratesTicks don't jump or fall from trees. They climb a grass blade, hold on with their back legs, and reach out with the front pair until something brushes past. This is called questing. Walk the center of the trail and you brush fewer of them.
Source: CDC, How ticks spread diseaseA blacklegged tick usually has to stay attached 36 to 48 hours before it can pass the bacteria that cause Lyme. Find and pull it the same day and the risk drops sharply, which is why a nightly tick check is the cheapest protection there is.
Source: CDC, Preventing tick bitesProduct labels and manufacturer guidance for DEET-based repellents caution that they can soften plastic, vinyl, and some synthetics, including sunglass lenses and fishing line. Picaridin labels do not carry that caution. Whatever you use, read the label before it touches your gear.
Source: EPA repellent fact sheets and manufacturer guidanceShort, sourced, no hedging.
Usually 36 to 48 hours. The CDC notes that in most cases a blacklegged tick must stay attached a day and a half or longer before it can pass the bacteria that cause Lyme. Pull it sooner and the risk drops a lot, which is why a same-day check is the cheapest thing you can do.
Sunscreen first. Let it set, then put repellent over it. The CDC advises against combination sunscreen-repellent products, because sunscreen needs frequent reapplication and repellent does not.
The CDC says do not use insect repellent on infants younger than 2 months. Oil of lemon eucalyptus and para-menthane-diol should not be used on children under 3 years old. For the youngest babies, dress them in loose long clothing and drape mosquito netting over the carrier or stroller. The CDC lists picaridin among its recommended repellent active ingredients; when applying repellent to children, follow the product label and CDC application guidance.
Tick nymphs, about the size of a poppy seed, are most active from late spring through summer and cause most Lyme cases, because they're so small they're easy to miss. Adult ticks stay active into fall and on warm winter days.
Nothing on this page is a Longsleeve number. Every fact traces to a public-health agency or a federal regulator. The full list, so a teacher, a reporter, or a worried parent can verify any line:
