Bedbugs may be a growing nuisance, lurking in mattresses and other hiding places until emerging to seek blood for their meal, but their bites do not appear to transmit disease, researchers said on Tuesday.

Resistant to many pest control efforts, the hardy pest is spreading to hotels, homes, subways and movie theaters.

"Five-star hotels are just as susceptible as little cheap ones. People bring them in with their stuff. The real problem is people taking them home ... because they're so difficult to get rid of," said Jerome Goddard, a Mississippi State University entomologist who wrote a report with a colleague on the topic in the Journal of the American Medical Association.

Goddard said there has been an "explosion" of bedbug infestations, with a sharp increase in reports to health departments and lawsuits against hotels.

"It started in hostels and hotels, but now it's in apartments and dormitories, in houses," he said. "And it's started to get in really weird places like movie theaters and subways. (In) ships, ferries, all kind of places."

Many people do not notice the bugs' bite and have no skin reaction. But some develop itchy bumps or ugly blisters, and a rare few have allergic reactions like asthma attacks.

Goddard sought to dispel suggestions he found in some earlier studies that bed bugs might transmit blood-borne diseases like the plague, yellow fever, hepatitis or HIV.

In the past, hepatitis was found in bedbugs in Africa. But in previous animal experiments, bed bugs fed tainted blood did not infect chimpanzees.

"At this time there's no evidence they're transmitting human diseases. That should allay fears," Goddard said.

Before their reemergence in the past decade, bed bugs largely disappeared from developed countries for 50 years, coinciding with wide use of the pesticide DDT.

But getting rid of infestations now is difficult, with few weapons to employ, Goddard said. The hardy bugs can live up to a year without feeding, have developed resistance to some insecticides and are not attracted to bait traps because they only feed on blood.

They favor seams in mattresses, crevices in box springs, the backs of headboards, spaces in baseboards, and behind loose wallpaper. When he settles into a hotel room, Goddard said he puts his bags in the bathroom and checks bed seams and closets for the 5-millimeter-long (0.2 inches) bugs or their tell-tale black feces marks.

"It's not related to cleanliness. It's not related to sanitation. It's related to people going around," he said, noting bed bugs usually hitch rides in travelers' luggage.

An experienced pest control expert can eradicate bedbugs. And there are mattress encasements that entomb the bugs.