Arlington, Va. ? “Don’t let the bedbugs bite.”

Doesn’t seem so bad in a cheerful bedtime rhyme, but it’s becoming a really big problem now that the nasty critters are invading hospitals, college dorms and even swanky hotels.

With the most effective pesticides banned, the government is trying to figure out how to respond to the biggest bedbug outbreak since World War II.

Bedbugs live in the crevices and folds of mattresses, sofas and sheets. Then, most often before dawn, they emerge to feed on human blood.

Faced with rising numbers of complaints to city information lines and increasingly frustrated landlords, hotel chains and housing authorities, the Environmental Protection Agency hosted its first-ever bedbug summit Tuesday.

Organized by one of the agency’s advisory committees, the two-day conference drew about 300 participants to a hotel in Arlington, just across the Potomac River from Washington. An Internet site notes that the hotel in question has had no reports of bedbugs.

One of the problems with controlling the reddish-brown insects, according to researchers and the pest control industry, is that there are few chemicals on the market approved for use on mattresses and other household items that are effective at controlling bedbug infestations.

Unlike roaches and ants, bedbugs are blood feeders and can’t be lured by bait. It’s also difficult for pesticides to reach them in every crack and crevice they hide out in.

The EPA, out of concern for the environment and the effects on public health, has pulled many of the chemicals that were most effective in eradicating the bugs in the U.S. At the same time, the appleseed-sized critters have developed a pesticide resistance because those chemicals are still in use in other countries.

Increasing international travel has also helped them to hitchhike into the U.S.

Bedbugs are not known to transmit any diseases. But their bites can cause infections and allergic reactions in some people. The insects release an anticoagulant to get blood flowing, and they also excrete a numbing agent so their bites don’t often wake their victims.