They're small, blood-sucking parasites perhaps living in the corners and crevices of our beds, feeding off us while we sleep.

Bed bugs, for decades, existed as myths, part of a rhyme our parents told us before bed. Now they've made an unwelcome return and those who know the buggers best say it's high time we start taking them seriously.

After all, getting a bed bug infestation "is a bit of a crap shoot," conceded University of Kentucky entomologist Michael Potter, meaning all of us are at risk.

Bed bugs used to be "incredibly common" in the early 20th century, Potter said. Back then, people routinely checked for them and carried insecticide while traveling.

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But the introduction of potent insecticides killed most of our bed bugs, banishing them from our homes and consciousnesses. The bugs, Potter said, disappeared from about the mid-1950s to the late 1990s. They became so rare people could no longer identify them and a new generation of pest control professionals weren't equipped to fight them, noted University of Florida research scientist Roberto Pereira.

But then they came "roaring back in the last five to seven years," Potter said, creeping into our couches, our apartments and even into the hotel rooms of our NBA stars. The reason why is a mystery, although Pereira and Potter suggest it's because the once potent insecticide is now banned, people travel more and the bugs have grown resistant to modern insecticides.

Now we're left avoiding them. But there are ways. Here's what you need to know:

They're small and flat

If you've never seen one, bed bugs are small, flat, reddish-brown bugs about the size of Abraham Lincoln's head on a penny.

They have an oblong shell and a tiny head. They typically live in areas where people sleep because at night they feed on our blood.

Unlike ticks or fleas, bed bugs don't latch on when they feed. They bite then scurry away to digest. "It's a creepy parasite," described Potter. "It's a little bit like Dracula."

They live off our blood

Bed bugs have to feed on human blood about once a week, Potter said. However, the U.S. Centers for Disease Control and Prevention claims they can live several months without a "blood meal."

Potter said bed bugs will adapt to your schedule. For instance, if you work the overnight shift, they'll learn to feed on you during the day.

They huddle on your mattress

Bed bugs don't form colonies or nest, but they do aggregate, usually within about eight feet of where a person sleeps.

It's popular to find clusters of them on beds and recliners. Very skittish, bed bugs don't like movement, which is why they feed on us while we sleep.

Popular places for them to congregate are in the seams of mattresses, in bed frames, headboards, dressers and behind wallpaper or clutter. A bed bug, notes the CDC, can travel more than 100 feet in a single night.

A third of us get bit, but don't notice

Bed bug bites look like raised welts and can cause serious allergic reactions in some people.

But a third of people don't experience any reaction. This only helps the infestation spread because people don't know they have the bugs.

Cleanliness has nothing to do with it

The stigma that a filthy home is more at risk of getting bed bugs just isn't true, Potter claims.

Unlike cockroaches, rats or flies, who feed on filth, bed bugs feed on blood. They only need a body. Bed bugs, the CDC said, have been found in five-star hotels and resorts.

So, where do they live?

Bed bugs are most often found in major metropolitan areas. However, over time, the pests have found their way to rural areas.

Anywhere there are close quarters, Potter said, the odds are better. It's a numbers game, he said, because the more people coming and going from a building increases the odds the bugs will find their way there.

Low-income housing also is a target because many people use old bedding and building staff may not take the steps to address the problem.

They don't carry disease

Bed bugs do not carry disease. At most, they're annoyances which cause itching and a lack of sleep.

How do we avoid them?

Experts say people bring an infestation into a home after they've gone to a place with bed bugs and somehow brought them back to their house.

This can happen just about anywhere: At hotels, while riding busses and trains, vacationing on cruise ships and bunking in dorm rooms. They attach to stuff, Potter said, not people. He's seen them on the bottoms of shoes, baseball caps and even Beanie Babies.

But it's unlikely you'll get them from places where people don't sleep. The places where people get some shut-eye are most at risk.

Potter advises people check around hotel beds when first checking in. Pull back the sheets, check the seam and corners of the mattress near the pillows and the headboard. Look for black spots, the bugs themselves or yellowish skins that bed bugs shed.

Try not to spread out in your hotel room. Don't place your open suitcase against a wall. Try to keep it closed and set it on a hard surface. Don't spread clothes across the hotel room.

Potter said each of us needs to strike a balance as to how paranoid we'll be in avoiding bed bugs.

"You got to be careful because you take all the joy out life," he said. "People just have to decide how apprehensive do they want to be."

Follow Sean Rossman on Twitter: @SeanRossman