A bed bug is shown at the Smithsonian's Museum of Natural History. (Carolyn Kaster/AP)

Baltimore and Washington ranked as the top two cities for bedbugs in a list put out by one of the leading pest control companies in the country.

Orkin ranked major cities based on data of where the company performed the most bedbug treatments from December 2015 to Nov. 30, 2016.

The ranking includes commercial and residential properties, the company said in a statement. The list came out Tuesday.

The top five cities were Baltimore, Washington, Chicago, New York and Columbus, Ohio. Portland, Ore., ranked 50th. On Orkin’s list last year, Chicago ranked No. 1 for the fourth year in a row and Washington ranked third. Baltimore ranked 10th.

A full list of this year’s bedbug rankings by Orkin can be found on the company’s website.

In 2015, another pest-fighting firm — Terminix — ranked Detroit and Philadelphia as leading the list of most infested bedbug cities. In that list, Washington did not rank in the top 15.

[Where the bedbugs bite: The most infested cities in 2015]

Known sometimes as “hitchhikers” by pest control experts, bedbugs can be carried easily in purses, luggage and other items. They can be found in homes, hotels, subway trains, libraries, offices and movie theaters. Their favorite food: blood.

“Anyone can get bedbugs in their home,” Orkin entomologist Ron Harrison said. Often people worry that having them is a sign of an unclean home, but bug experts say that is not the case.

“Bedbugs only need blood to survive,” Harrison said, noting that his company has treated bedbugs in million-dollar homes.

What makes catching bedbugs hard is that they are small — typically about the size of an apple seed when fully grown — and can live for up to a year without feeding, experts said.

[How’d the bedbug get its bite? Scientists look into its genome for clues.]

Bedbugs are also good at hiding, including in cracks and crevices of headboards, on beds and in mattress seams. They can be as far as a five feet from a bed, according to Orkin, and they multiply fast.

The National Pest Management Association said in 2015 that nearly 99.6 percent of its professionals across the country “have treated bed bugs in the past year, up from five, 10 and 15 years ago,” the Orkin statement said.

In a statement, Harrison said bedbugs are a growing problem, noting that 10 years ago it was a “virtually unheard-of” issue.

“We have more people affected by bedbugs in the United States now than ever before,” he said. Orkin noted that four cities that had not been on its list in previous years were on it for the first time — Greensboro-High Point-Winston Salem in North Carolina; Salt Lake City; Portland and Las Vegas.

Orkin experts said the first signs of bedbugs are often seeing the critters or the small dark stains that they leave.

The company recommends checking frequently for them and not having piles of clutter around the house.

When traveling, Orkin recommends keeping luggage away from beds and walls. The safest place for stuff, they said, is the bathroom. And once a traveler has returned home, checking all items is recommended.

Putting clothes into a dryer for at least 15 minutes on a high setting also helps.