Everything You Must Know About Mosquitoes This Summer

Ah, summer! More sunshine, more outdoor adventures…and more mosquitoes (blech). The vampiric little buggers peak in July and August, and they're not just gross and annoying—getting bitten by the wrong one can leave you battling for your health. But that doesn't mean you have to spend the next few months on house arrest. Your manual to outsmarting mosquitoes starts here.

More than 3,000 mosquito species exist worldwide, but if you live in the United States, you only need to be concerned with six of them: Yellow fever mosquito (also known as Aedes aegypti), carries Zika, chikungunya, and dengue; Asian tiger mosquito (a.k.a Aedes albopictus), which also carries Zika, chikungunya, and dengue; Northern house mosquito (a.k.a Culex pipiens), carries West Nile; and Culex tarsalis and Culex nigripalpus, which also carry West Nile.

Many mosquito species don't bite at all. Of those that do, it's only the females who are bloodsuckers—they used the protein to produce eggs.

"Mosquitoes will breed quite happily in something as small as a discarded soda bottle cap," says Joe Conlon, a retired U.S. Navy entomologist and a technical adviser for the American Mosquito Control Association. "You have to be fastidious." Clear the water from outdoor kids' toys, birdbaths, flower pots, clogged gutters—even the tarp you toss over the wood pile, if little puddles tend to pool there. Mosquitoes take about a week to grow from egg to adult, so go on a water-dumping mission every four or five days to ensure you're not hosting the next generation.

Some mosquitoes are aggressive, in-your-face biters, but the Aedes aegypti is sneaky instead. "Because it lives closely with humans, right in our houses, it has modified its biting behavior to go undetected," says Jonathan Day, PhD, a medical entomologist and mosquito expert at the University of Florida. The buggers tend to fly close to the ground and target the feet and ankles, and a chemical in their saliva makes their bites less painful—so you might never even know you've been bitten.

Any breeze stronger than 1 mile per hour is enough to deter mosquitoes. On a still day, grab a plug-in box fan to create the same effect. "Just make sure to point it at your lower extremities," says Day. "Mosquitoes fly low to avoid the wind, so a fan on your face won't protect your feet."

"Your risk of getting bitten is reduced considerably just by covering exposed skin," says Conlon. Limit loose-weave fabrics, like linen and cotton, in favor of tighter weaves, like synthetic and athletic fabrics, that most mosquitoes struggle to bite through. (One more reason to embrace your athleisure look!)

Mosquitoes zero in on tasty victims by searching for carbon dioxide. Release more, and you'll attract more hungry beasts. Some factors that raise CO2 production (such as pregnancy) are impossible to tone down, but you'll also pump out more while exercising or drinking alcohol. "Mosquitoes don't fly very fast, so they can't catch up with you when you're running," says Day. "But you might notice that afterward you get 10 bites while stretching for a few minutes." Consider taking your workout cooldown inside.

Experts agree: If you do only one thing to keep yourself safe from mosquitoes, apply repellent before you spend time outdoors. How much time? "During the dawn and dusk hours, when mosquitoes tend to be more active, spray yourself even if you're just running to the mailbox," says Conlon. "One colleague at the CDC contracted West Nile when he went out to check the mail—and that was the sickest he's ever been in his life."

When you're going camping, reach for DEET at 25% concentration. "DEET has a bad reputation, but the health concerns are greatly exaggerated," says Conlon. "Look through the medical literature and you'll find that most adverse reactions are tied to people drinking or overusing the stuff." When it comes to warding off mosquitoes and ticks, DEET is considered by most experts to be the gold standard, which makes it essential if you're spending days outdoors. Try Off! Deep Woods Dry ($6; amazon.com).

When you're hosing a family barbecue, reach for picaridin at 15 to 20% concentration. Derived from pepper plants, picaridin is one of the most popular repellents outside the U.S.—and unlike some repellents, it's safe for kids ages 3 and under. "Picaridin has a light, nongreasy feel, so it's a good one if you need to wear repellent daily," says Conlon. Try Sawyer Picaridin Premium ($9; amazon.com).

Oil of lemon eucalyptus at 20 to 40% concentration is virtually as effective as DEET against ticks and mosquitoes, though it's not as long-lasting. Note: the essential oils will not work. Try Repel Lemon Eucalyptus ($6; amazon.com).

The reason can't be reduced to "sweeter blood" (sorry, Granny), but there is a genetic component: In a 2015 study published in Plos One, identical twins (who have the same genes) attracted mosquitoes at the same rate, while fraternal twins were bitten at very different rates. "Humans put off more than 300 different compounds of smells, and some chemicals, like lactic acid, are more attractive to mosquitoes," says Conlon. "It's unlikely we'll ever ferret out all the nuances of what makes someone a mosquito magnet."

Almost anyone who gets a mosquito bite will feel itchy, but that sensation can be worse for people who tend to develop more pronounced bumps or hives. So, what causes that itch? Turns out mosquitoes inject saliva into your skin while they're drinking your blood, and your body pumps out histamine in response.

Planting lemon balm and citronella in your garden won't naturally repel mosquitoes. The pests do avoid these plants, but once a hungry female is after blood, no amount of citronella in the air will mask your human scent.

None of the many ultrasonic devices and apps that are marketed as mosquito repellents are proven to work. Likewise for "natural" wristbands or clip-on devices that contain DEET. Any repellent needs to be applied directly to your skin to block a mosquito's interest in biting you, says Conlon.

Combination lotions that include both mosquito repellent and sunscreen might seem like a two-birds-one-stone bargain, but the CDC recommends against using them. Sunscreen needs to be applied liberally and frequently, so keeping your skin UV-safe could mean you'll wind up slathering on more repellent than you need to.

If you cover yourself in repellent, wear the right clothes, and still get bit, there are a few steps you should take to soothe itching and prevent infection. First, wash the bites using mild soap and cold water, which can provide some relief. If the bites still itch, treat them with anti-inflammatories or topical antihistimines, like Benadryl gel ($15 for 2; amazon.com).

Just a few years ago, Zika wasn't on most Americans' radar. Now, many consider the virus carefully before making travel plans–and take steps to prevent mosquito bites during trips. Symptoms are typically mild, and include fever, rash, joint pain, and red eyes, but only one in five report any symptoms.

Expectant mothers are most at risk because of Zika's known link to birth defects (especially microcephaly, where a baby's head is smaller than normal at birth). But just because symptoms are mild (if they appear at all), that doesn't mean men and women who aren't planning on conceiving shouldn't be concerned. The virus has been tied to Guillain-Barre syndrome, which causes the immune system to damage nerve cells.

For women, it's believed the Zika virus clears within two weeks, and then you're immune. So if you later get pregnant (the CDC recommends waiting eight weeks before trying to conceive), your baby will likely be fine. It's a different story for men, though, because Zika may survive months longer in semen. Men returning from a Zika-infected area should refrain from having unprotected sex for at least two months (six months if they've had symptoms), or for all of a partner's pregnancy.

West Nile is a potentially fatal virus that's especially hard to stamp out because it also infects birds, which then bring the virus to new areas. West Nile has been reported in all 48 continental states. Only one in five people experience symptoms such as vomiting, diarrhea, headaches, and joint pain. Fewer than 1% of patients have severe neurological symptoms, such as seizures, paralysis, or coma, that require hospitalization.

Dengue infects nearly 400 million people every year. In most of the United States, it rarely occurs, though there have been outbreaks in Florida and Hawaii. Symptoms include a high fever and at least two of the following: severe headaches, eye pain, nosebleeds, bleeding gums, joint or bone aches, and low white blood cell counts. Infection can be fatal, so if you suspect dengue, call your doctor ASAP.

This virus first reached the United States in late 2006; fortunately, experts think that chances of a widespread outbreak are slim. Watch for excruciating joint pain and a fever that sets in a few days after the mosquito bite. Symptoms typically last about a week, though the debilitating joint pain may linger for months.