Bed bugs, you could say, are having a moment—or, perhaps, un moment.

Paris was the latest scene of an outbreak that made global headlines as the city that’s hosting the 2024 Summer Olympics scrambled to arrest a resurgence of the insects that are on every traveler’s no-go list.

But Paris is hardly alone when it comes to the pests; bed bugs can be found almost anywhere in the world and at any time.

So, what can travelers do should they encounter the pesky problem on the road? Here’s what to know.

What are bed bugs?

Bed bugs are wingless parasitic insects found across the Americas, Africa, Europe, Asia, and Oceania.

The University of Florida’s Institute of Food and Agricultural Sciences describes bed bugs as “blood-feeding parasites of humans, chickens, bats and occasionally domesticated animals,” and adds that they are sometimes referred to as chinches, red coats, or mahogany flats.

“Bed bugs have probably been associated with humans for more than 100,000 years,” says Rob Anderson, an associate professor in the biology department at the University of Winnipeg in Manitoba, Canada, who teaches a class on blood-feeding pests, which include bed bugs as well as mosquitoes, fleas, ticks, and other insects. “They are obligate blood feeders, which means they must have blood to survive and reproduce.”

Considered nest parasites—organisms that reside in the immediate area where the animal host (that would include you) spends most of its time—they live off the blood or skin tissue of the host animal. “Bed bugs are aptly named because they hang out in and around the bedroom where their blood hosts spend lots of time and reliably return. Bed bugs only come onto a host such as a human to blood feed then return to a nearby crevice or hiding place to digest the blood ,” says Anderson.

Adult bed bugs are flat and oval-shaped, grow to about 4 to 5 mm long, and are equipped with “piercing-sucking mouthparts, so they bite and suck blood like a mosquito” according to the University of Florida.

The U.S. Centers for Disease Control and Prevention (CDC) says two species of bed bugs are “usually implicated in human infestations”—Cimex lectularius and C. hemipterus, the former of which is considered cosmopolitan (meaning they are “found or present all over the world,” says Anderson) and the latter appear mostly in the tropics and subtropics.

Bed bugs most often feed on people at night while they sleep and tend to bite the exposed upper part of the body. And while they’re undoubtedly a nuisance, bed bugs are not considered to be “effective vectors of disease” according to the CDC, which notes that the primary medical risk is associated with inflammation from their bites.

Where are bed bugs commonly found?

Bed bugs are some of the world’s most ubiquitous travelers.

“They are to be found in street-side hostels, huts in small villages, and first-class hotels,” says Anderson.

“Many hotel chains regularly deal with them, but they seldom admit it because it’s not good for business,” he says, attributing the presence of bed bugs in hotels to the “the nature of their transitory, ever-changing clientele,” he wrote in an email to AFAR.

According to the CDC’s website, bed bug infestations tend to happen near areas where people sleep, which could mean anywhere from hotels and cruise ships to buses and trains.

The bugs tend to feed at night and hide during the day in the seams of mattresses, behind headboards, inside cracks and crevices in a room, in bed frames, furnishings, and box springs, among other locales, according to the CDC.

Once inside a dwelling, says Anderson, bed bugs’ numbers can build up long before humans even notice them—especially if there are pets in the house that they can feed on. That’s because pets might take the brunt of the early blood-feeding attention of the initial few bed bugs introduced, he says, before they’re present in enough numbers to attract the attention of humans.

He adds, “They move around the world every day with travelers (usually hitching rides in luggage) and sometimes to home where they may establish.”

For people who bring bed bugs home with them from their travels, Anderson warns you might not realize you have a stowaway until some time after returning home.

How do you know if you have bed bugs?

The most common sign of having bed bugs or having been exposed to them is the appearance of their bite marks on your upper body, namely on the face, arms, neck, or hands, after sleeping someplace where they live.

“Often the red spots are in groups of two or three because bed bugs often poke their needle-like mouthparts into the skin several times until they lacerate good blood vessels with enough blood to flow and feed on,” says Anderson.

According to the CDC website, most people won’t feel the bed bug bite itself when it happens since the insects inject an anesthetic and anticoagulant when they bite their victim (how thoughtful of the buggers).

“They tend to feed at night when people are sleeping because they’re less likely to be detected, and they only stay on the human skin for as long as it takes to feed,” says Anderson, adding, “after which they return to the nearest hiding place, some kind of crevice.”

You can look for signs of bed bugs—both their physical forms in the crevices of mattresses and folds of sheets as well as signs of rust-colored blood spots on your mattress (it comes from them being crushed and their fecal material, which is filled with blood, according to the CDC). “The adults are easily visible,” Anderson says. “In large infestations, they often leave a line of blackish, stinking blood feces deposited wherever they hide when off the blood host.”

Look for a dark line right where the mattress or box spring sits against the bedroom wall, he says, which is an indicator that bed bugs are present.

What should you do if you do get bed bugs?

If you get bed bug bites, try to avoid scratching them, as that’s likely to cause more problems by opening up your skin to secondary infections, Anderson says.

Thankfully, “They’re not transmitters of worrisome pathogens as far as an astounding amount of evidence goes,” he adds. “But the bites can be annoying, especially for people with allergic sensitivity to the saliva bed bugs inject when they are feeding (as all blood feeding pests do).”

To relieve the itchiness, he suggests applying topical antihistamines such as Benadryl spray. (As with the use of any drug, consult with a doctor beforehand to make sure you’re not allergic or to address any other concerns.)

If you suspect a bed bug invasion where you live, contact a trusted pest control company experienced in treating bed bugs to inquire about fumigation services and other available methods of dealing with them.

What are the best ways to avoid getting bed bugs?

You’re at risk of encountering bed bugs both at home and nearly any place you travel.

According to the CDC, “Anyone who travels frequently and shares living and sleeping quarters where other people have previously slept has a higher risk of being bitten and/or spreading a bed bug infestation.”

Lydnsey Matthews, senior commerce editor at AFAR, and a firm believer of never putting your suitcase on your bed (in part to help prevent the spread of bed begs), has herself experienced bed bugs three times and has some advice.

“They are bigger than you think—an adult is the size of an apple seed,” she says, so look for them in the seams of headboards and mattress and under sheets, where you may find their eggs, feces, or the bugs themselves.

When you get home from a trip, she suggests washing and drying everything on high heat. If your suitcase can’t be washed in a washing machine, it’s a good idea to steam clean it at a high temperature, she says.

There are some things you can do to avoid bringing bed bugs home with you, too.

Anderson says you can reduce the risk of bed bugs invading your bags and suitcases by keeping them inside well-sealed large garbage bags when staying in temporary housing, including hotels. He says he inspects any hotel room or apartment he rents to look for the obvious signs of bed bugs and checks his belongings for signs of them, too, before packing up and returning home.

In 37 years of traveling around the world and doing research on bed bugs, Anderson says he’s encountered them and been bitten by more than his fair share—but he has so far managed to avoid bringing any of the insects back home with him as a souvenir.

“Bed bugs have been an occupational hazard for me because of the travel to the tropics and often staying in remote, very rudimentary digs in field research sites where bed bugs just exist in significant numbers,” he says. “I’m pretty rigorous about inspecting my luggage, or spraying it or sealing it in containers if I suspect there are bed bugs wherever I’m staying at a given time.”