While experts cite a host of reasons for the upsurge, they agree on one thing: the bugs, which were mostly eradicated in this country at midcentury by now-banned pesticides like DDT but remained a constant scourge overseas, are finding their way back to the United States through an increase in global travel.

And in cities like New York, where neighbors are often separated only by bricks and mortar, one person’s infestation is everybody’s problem, since bedbugs can crawl through walls and along wiring and pipes, and hitchhike on clothing, furniture, luggage and more. In this city of 8.3 million, it seems as if everyone has a bedbug story.

Just ask Gale A. Brewer, a self-appointed bedbug evangelist and a City Council member from the Upper West Side. She prodded the Mayor’s office to convene a bedbug advisory committee last fall, after years of what she and others felt were woeful public policy inadequacies in the face of the relentless advances of what some have called “the pest of the century.” (The committee — entomologists, civic policy experts and advocates for children, the elderly and others — will issue its recommendations next month.)

The breadth and scope of the problem has been captured anecdotally in anguished tales — the family living in a tent outside their lovely-but-infested Long Island home, the woman in the Upper West Side one-bedroom who spent $9,500 on extermination and lived out of plastic bags, at friends’ apartments, for three months — posted on blogs like bedbugger and newyorkvsbedbugs, the likes of which have been spreading like, well, bedbugs, over the last few years. They are told over and over at community board hearings presided over by Ms. Brewer and others, and recorded in mainstream media. Another picture, though still incomplete, comes from the city’s Department of Housing Preservation and Development, which has been tracking bedbug complaints and violations through calls to the 311 help line. Consider that six years ago, there were 537 bedbug complaints and 82 violations (in other words, verified infestations); last year, complaints topped out at nearly 11,000, with 4,084 violations cited (nearly double that of the previous year).

But the complaints registered with the department and 311 relate only to rental properties; reports of bedbugs scampering through the private sanctums of hotels, co-ops and condos, colleges and office buildings remain largely uncounted, though real estate lawyers and brokers report that co-op minutes reveal a world that’s just as infested as the rest of the city.