Where Do Bed Bugs Come From? A Quick, Non-Gross Explainer

Just saying the words “bed bugs” is usually enough to make most people visibly shudder, haunted by visions of recurring infestations and expensive fumigation. So we talked to Brittany Campbell, Ph.D., staff entomologist for the National Pest Management Association—and probably one of the few people in the world who seems genuinely excited to talk about bed bugs—to demystify the pests.  

It’s not your plants or rotting food. “Bed bugs have to be brought in by a person,” Campbell says. However, because they only stay on the body for a few minutes, rather than the long haul like a tick, they’re more likely to travel in luggage; they make themselves comfortable in suitcases, purses, and in the folds of clothing. 

Bed bugs also only live indoors, so you won’t pick them up on a hike or picnic. But that’s really the only generalization that can be made about their habitat. “Any place that people stay or frequent is susceptible to bed bugs,” Campbell says. That means you can find them in hotels, summer camps, and other people’s houses. 

Here’s the bad news: The reason the little pests bite is because they consume a strict blood-only diet, and while they will nip at cats and dogs, “humans are their favorite blood source,” Campbell says. (If you’re thinking of cultivating a chicken coop or attic bat colony, note that bed bugs also enjoy these two species as hosts and can hide in nests and roosts.)

Here’s the good news: They don’t spread any diseases. “They’re not an extreme threat, just an uncomfortable nuisance,” Campbell says.

Live bugs are similar in shape to ticks and “very much visible to the naked eye,” Campbell says. They’re about the size of an apple seed, with a rounded abdomen, six legs, and smaller head. You may be able to see live bugs on a mattress, particularly around a mattress tag, within the seams, near the headboard, and in bedding folds. “Any spot that provides a dark crevice or hiding spot is going to be a typical place where you’d find them,” Campbell says. 

Also, bed bugs don’t just limit themselves to fabric. “It’s possible for them to infest about anything in a room,” says Campbell. “I’ve even seen them in picture frames. Anywhere that provides a good place for bed bugs to hide is a potential place that they may be found.”

But while you might be able to see live bed bugs, you’re more likely to come across other signs that they’ve taken up residence. You may find exoskeletons they leave behind, which look like ghosts of the bugs themselves: bug outlines but light in color and very thin. You may spot eggs as well, which look like small grains of rice. Additionally, after bed bugs bite, they digest the blood they’ve consumed, and it makes its way through their systems and comes out as dark spots that look like ink stains. (We know: We said “non-gross explainer.” We’re sorry.) These spots are brownish-blackish in color, not red. If you see brighter red spots on your sheets, it’s more likely from where you got a bite or scratched in your sleep.

Maybe, but it’s not a foolproof identification strategy. 

“Bites are not the way to confirm a bed bug infestation,” says Campbell. “Everyone’s bites look a little different—it’s based on your immune system, so everyone reacts differently.” While some people may get the itchy red welts most associated with bed bug bites, others may have a milder or no reaction, and even the time it takes your body to react can vary.

There’s a myth that bed bug bites can be identified because they bite in a line of three, but it’s unfortunately not that easy. “Bed bugs may pierce the skin in several spots when searching for a vein, but they do not specifically bite in rows of three,” says Campbell. “The bites can be sporadic and are dependent on how a person is sitting or sleeping and where bed bugs have access to the skin.”

Unfortunately, that’s a definite yes. Once you’ve gotten a few hitchhikers, they can make their way through an apartment on their own. They can crawl behind baseboards and move through wall voids, as well as plumbing and electrical lines between apartments. “I’ve even seen bed bugs walking in the open down a hallway,” Campbell says. (Cool, cool.) Communal lounges can also be a hazard, as someone may shed a bed bug from their clothes and it will hang around the couch to find a new host.

Well, we can’t guarantee never. “There’s no really fail-proof way to avoid bringing bed bugs home,” says Campbell. “The only real way to avoid bed bugs is to thoroughly inspect any place that you spend the night.”

When you arrive at your destination, stash your luggage in the bathroom, ideally in the tub, where bugs are less likely to scramble. Then pull back the bedsheets and look for signs like the brownish-blackish spots, skins, and even live bugs, especially in the seams of the mattress and box spring and corners near the headboard. That should cover most of it, but if you’re feeling extra paranoid, you can pull the headboard away from the wall and look into side tables and any other furniture in the room. 

Maybe a little. The EPA offers a strategy that nearly resembles a military assault and primarily involves treating all your infested items via extreme temperatures, a year-long air-sealed quarantine, or just discarding them. 

Generally, though, bed bugs are more of a “just try really hard not to acquire them, and if you do, call in the professionals” problem. They’ve developed resistance to most of the products such as bed bug sprays that are currently available on shelves and excel at hiding away in small spaces that most amateurs just won’t be able to reach or even find. And if you live in an apartment, your entire building likely needs to be treated due to bed bugs’ evasive abilities. “They’re really elusive creatures,” says Campbell. “They’re really difficult to control on your own.”

Don’t panic. There are ways to handle an infestation, and as we said, the itching is the only side effect; bed bugs won’t pass along any diseases or severely damage your property.