PORTLAND, Ore. (AP) -- For centuries the evening couplet "Sleep tight, don't let the bedbugs bite" settled like an itchy benediction on kids headed for dreamland. The word "bedbug" was not then mentioned in polite society.

But the apple-seed-sized insects, long subdued by insecticide, are making a comeback and are showing up in a place surprising to the proprietors--the Oregon Health & Science University.

They were found last weekend crawling from a fanny pack that had been stored for safekeeping with other patients' belongings for two weeks, according to a hospital spokeswoman.

A search revealed more in offices surrounding the patient admitting area, but none in patients' rooms.

"We talked to our outside experts who deal with bugs, and they said you need to treat it aggressively and quickly," Liana Haywood, a spokeswoman, said.

Bedbugs are wingless, red-brown insects that hide in cracks in furniture, floors and walls during the day and emerge at night to suck people's blood, leaving small clusters of extremely itchy, red welts. But studies have found they aren't effective carriers of human diseases.

Insecticides suppressed them for the past half century, but they appear to be bouncing back in the United States and Europe. They can survive several months without eating.

A 2005 Canadian study found bedbugs in nearly a third of the homeless shelters in Toronto. Researchers surmised the pests move from place to place in personal belongings.

At OHSU, Oregon's medical school hospital, pest-control workers are removing all office furniture for offsite decontamination, Haywood said. The hospital may replace the carpet in the affected area.

The hospital disposed of the mattress used by the fanny pack owner and steam-cleaned the room as a precaution.

The cleanup will take weeks, Haywood said. Patient admitting has moved down the hall.

"We don't have any estimates exactly on the costs," she said. "We decided it's more important to protect patients and employees rather than let it become a lingering problem."

State health inspectors opened an investigation Wednesday after learning of the incident from The Oregonian.

State regulations don't require hospitals to report insect infestations, said Ron Prinslow, manager of the state's health care license and certification program.

"We'll go onsite and verify whether they took appropriate steps," Prinslow said. "I don't think there is any way they could have prevented this."