They have taken over the smartest New York venues, bringing hysteria to the most sophisticated city on the planet. Now they’re coming here.

Bedbugs are taking over Manhattan, and you might not even know you have them.

I was standing barefoot in my pyjamas when two men and a beagle entered my bedroom and shut the door. Minutes later they emerged and Charlie, the caretaker of my apartment block, looked right at me. “Of all the tenants in this building,” he said, shaking his head and sounding resigned, “I was praying it wouldn’t happen to you.” The other man, Oscar, from The Bed Bug Inspectors, was less emotional. He delivered the outcome like a man who has grown accustomed to breaking bad news.

“The dog scratched,” he declared.

“The dog scratched?” I repeated the words every New Yorker dreads hearing. “Are you completely sure?”

Like being mugged, finding the love of your life or living next door to a serial killer, you never think it will happen to you. Especially if you’re like me: obsessive about germs and dirt, neurotic about bugs and illness, won’t touch the pole on the Tube, and would sooner get whiplash than let your neck rest on an airline seat. “But I don’t have any bites,” I protested. “And I’ve never seen a bug!”

When I made an appointment for the bedbug-sniffing dog to visit, I’d assumed I was paranoid. Which is usually the case. Sure, I’d seen spots on my white sheets that looked like poppy seeds. But I didn’t actually think I’d have them. My friend Zoe had them: enormous, itchy welts had covered her entire body, and at first she’d thought she’d been bitten by a voracious mosquito. Because I had none of these symptoms, I was still sure I would be fine.

Everyone knows someone who has had them, yet people will admit to having herpes before they’ll admit to having bedbugs

I wasn’t. The dog scratched, and dogs are 95% accurate in detecting live bedbugs and eggs; they can pick up the scent from up to 5ft. And if you have one bug, it’s treated like an infestation. Given their reproduction rate, all you need is one. From that point on, it was like being asked to believe in God. With no proof He exists, you act like He’s there. Charlie put his hand on my shoulder and sighed. “We’ll get through this.”

If there are 8m stories in New York, 7m of them right now are about bedbugs. Everyone knows someone who has had them, and they whisper their tales of woe with shame. People will admit to having herpes before they’ll admit to bedbugs. Not me. I was too consumed with the irony of the situation to worry about the stigma.

How could it happen? When I told friends, their response was sympathy followed by concern. For themselves. Several completely shunned me (“They’re hitchhikers!”). I found it funny. But if I were the sort of person who had a thriving social life, I’d likely have been very depressed.

Compared to others, my handling of the situation was measured; the tales in New York are epic. People are moving out of their homes, spending thousands to get rid of them, only to have them return. They are finding them in the seams of pillows, inside their handbags, in the cracks in the floor. And because bringing the bugs into your home is random, nobody feels safe. Also, the pandemic shows no signs of abating. Every day bedbugs are being discovered somewhere new. They have been found at the Metropolitan Opera and Carnegie Hall — though so far only in non-public areas — in department stores, cinemas, the basement of the Empire State Building, and twice at the United Nations. They’re in the back of taxis and on the seats at subway platforms — anywhere people sit. Juicy Couture and Nike Town have fought infestations. The fact is, if you leave your house, you can get them anywhere, any time.

Checking the mattress in a hotel room is the most widely known preventative measure — but you’ll need to check the bed frame, the box spring, the headboard, the closets, the carpet, the light sockets and every other crack and crevice; otherwise, you’re not inspecting thoroughly.

I thought if I don’t see them, and I’m not getting bitten, I don’t have them. Wrong! Adult bedbugs are reddish-brown, flat and 1/2in long. Their bodies become engorged with blood after they’ve eaten, so yes, you can see them. But the young ones — nymphs — are translucent and only become brownish as they age.

The eggs are white and nearly colourless. You have to know what to look for. It helps to have a magnifying glass. Which is why the bedbug-sniffing dogs are the first line of defence. The Bed Bug Inspectors have canines trained to detect the scent of live bugs too small to be seen by the human eye. I was told it’s a good thing I noticed those faecal spots on my sheets. That’s when it hit me what I was in for. When identifying faecal matter had become one of the “good things” in my life.

Less than 24 hours later, my apartment was declared a hot zone. First, I received a document on how to prep. My head ached as I read what would happen.

Exterminators arrived and bagged up everything in the room. The mattress was encased in a bedbug protector (which seals in and smothers anything alive) in preparation for the first chemical treatment (there were three in total, with two weeks between visits).

Everything on the bed went to the dry cleaners along with all the clothing that could not be laundered in hot water and a hot dryer. Silk blouses and scarves labelled “hand-wash only” were ruined, and almost everything else shrank from the dryer. I guess another “good thing” was letting go of any emotional attachment to clothes. The exterminator would come to steam-clean every surface on a daily basis. On one occasion I arrived home to find him watching TV and eating a sandwich. “What are you doing?” I asked. He told me he hadn’t had breakfast. He was a nice man, so I asked if in future he wouldn’t mind not hanging out when he had finished working.

Bedbugs do not jump from person to person like fleas — but it doesn’t matter. Once you tell someone you have bugs, expect them to keep their distance. They are not classified as a health hazard, as they don’t transmit disease. However, they’re a mental-health hazard that can be emotionally, physically and financially draining.

According to the National Pest Management Association, bedbugs cost American industry $258m in 2009. And if you think the epidemic is coming to Britain, think again. It’s already here.

Louis Sorkin is an entomologist who has worked at the American Museum of Natural History since 1978. His office looks exactly the way you’d expect the office of a bug expert to look — filled with typewriters, books about insects, drawings of spiders.

We go down a hallway of glass tanks filled with giant cockroaches and arachnids. This is not the place for someone with an insect phobia. We sit in the lab next to a sealed jar containing hundreds of bedbugs. There are, he explains, around 90 species. The real problem is cimex lectularius, the common bedbug — the species we’re dealing with. They are transferred by people — on clothing or luggage — and like to feed on people, dogs, birds, cats and mice. “Most cities around the world have a bedbug problem. The pandemic has been caused because people have been unaware. They snuck up on us. Then there is cheap travel to areas where bedbugs are a problem, so they are transferred,” he explains.

They’re not life-threatening, and they don’t transmit disease, but they’re very difficult to get rid of

They can survive for around 18 months in a dormant state, so the female bedbug can lay around 350 eggs, so if a pregnant one happens to land on the back of your coat, you’re bringing home an infestation.

Sorkin shows me what a nymph looks like. As I watch it scurry inside the jar, it resembles a tiny speck of moving translucent lint. “There’s no way I would be able to see that on a white bed sheet,” I exclaim. He suggests I get pastel sheets.

“You have to know what bedbugs look like,” he states. “All five stages. Wherever the female happens to be harbouring, she can lay eggs. It can be within a wall or furniture. "That’s why you have to do a treatment again after 14 days — one egg cycle. The nymphs emerge all pale-coloured. If you’re going by bites, you may never know you have a problem.”

This is confirmed by Jeff Eisenberg, owner of Pest Away. “If you think that because you’re not getting bitten you don’t have them, that would be incorrect: 90% of men and 40% of women don’t manifest bites,” he says. When sores appear on the skin, it is because people’s immune systems have reacted to the bites, or the bites have become infected. Some people’s immune systems react to a chemical the bug delivers when it bites, which anaesthetises the skin, or to the bite itself. It is also possible to scratch and infect the bites, or for the bites to flare up from environmental pollution such as exhaust fumes. I was one of the “lucky” ones — my bites remained invisible.

Eisenberg works in a small, cluttered office on the Upper West Side. Sitting on a cabinet is a framed photo of him with his arm around Bill Clinton — he treated his offices. His book is out next spring: The Bedbug Survival Guide.

Eisenberg is the Dalai Lama of pest control for freaked-out New Yorkers desperately seeking guidance. He currently gets 300 calls a week. When I arrive, there’s an uncomfortable-looking blonde woman clutching a tan Hermès bag close to her cashmere chest, paying for bedbug essentials. “Don’t write about me!” she snaps.

The offices of Pest Away are stocked with what Eisenberg considers the bare necessities. Luggage sprays, bedbug-certified mattress covers, ClimbUp insect interceptors (bowl-shaped devices) and the Rolls-Royce of bedbug protection: PackTite.

This is a portable decontamination unit that plugs in and heats up personal items to a temperature proven to kill all stages of bedbugs. You can put your entire suitcase in it — including books, shoes, files and papers. It sells for $320. Alas, there is a waiting list. Amazon has completely sold out.

I add my name to the list and ask how long it will take. Three weeks. Three weeks? “If you’re lucky,” his assistant adds. And therein lies what is possibly the most ominous part of the whole bedbug epidemic. Sometimes, no matter how well prepared you are, it all comes down to luck.

You can be the unlucky person who sits in the airline seat after someone who has bedbugs

“Yes,” Eisenberg exhales with frustration. “You can be the unlucky person who sits in the airline seat after someone who has bedbugs. There are thousands of people who are infested but are too sick or elderly, or don’t care because they don’t manifest bites — and wherever they go, they’re transferring them.” One person in a high-rise can spread them to the rest of the building, he points out. Yes, they go through the walls.

The pests are driving patients to psychologists’ couches. But according to Eisenberg, that’s one of the worst places to sit. “Therapists’ offices are loaded with bedbugs.” Instinctively, I lift my bag off the floor and put it on his desk. Eisenberg is helping British clients implement his treatments. He claims it’s an epidemic in Britain. He speaks to pest-control companies and clients constantly — and nobody is denying the problem. Why, then, does it not have the seriousness it attracts in America?

“Europeans, to put it mildly, have a higher tolerance for pests,” he says. Both Eisenberg and Sorkin suggest I speak to one of the most dedicated exterminators of bedbugs in the world.

He is a full-time bedbug specialist whose attention to detail and understanding of the pest is widely respected in an industry loaded with imposters. It’s turned him into somewhat of a guru. And the best part: he’s British and based in London.

“Hallelujah!” David Cain calls out when I tell him I’m writing about the pests in Britain. “It’s about time.” Cain’s company, Bedbugs Limited, which is based in Battersea, south London, has in the past seven years treated more than 17,000 properties, on average 10 cases a day. Five years ago it was five or six calls a week and now it’s hundreds. His website gets 20,000 hits a day. His small team of skilled technicians will treat infestations anywhere in the country. In London, his fee is £125 per room.

His company has conducted research getting local authorities to supply data under the Freedom of Information Act. From 2003 to 2007, he claims, the problem tripled across London. A spokesman for Rentokil says that there has been a 24% national increase in bedbug jobs over the past year.

Cain is an evangelist for spreading information about the rise of the bedbug. “In 2005,” he says, “there was not a single picture of a bedbug on a website in Europe.” Do your research, he advises, because they are here and unlikely to go away.

I mention to Cain that I read that Tesco will launch a new bed that repels bugs — it works because the mattress is soaked with bacteria found in probiotic yoghurt that repel them. He lets out an exasperated sigh. “They haven’t found a solution for bedbugs,” he laughs. “They’ve found a way to support the dairy industry.”

Historically, there is a lot of misinformation about both the bug itself and the treatment. Old-fashioned methods like airing the bed and turning the mattress work for dust mites but are in no way effective at eliminating bedbugs.

The temperature in the home is no indication either: anything above 12C will enable them to reproduce.

“They’re a pest man first picked up in caves,” Cain explains. “They’re not life-threatening, and they don’t transmit disease, but they’re very difficult to get rid of.” Cain traces the shame and stigma back to the way the problem was dealt with in the 1940s and 50s, when the implication was, if you had bedbugs you were dirty. In some respects, Cain is both optimistic and fatalistic. He hopes the current media attention will focus the British public on the problem at hand and bring them out of the denial stage. “Social responsibility and communication are paramount,” he says. He also predicts that things could get much, much worse.

The only way not to bring them home again would be to never go out. But even that’s not foolproof.

“It will equal what is happening in New York if nothing is put in place to stop it. They are an exposure pest. And with the Olympics coming to London, you will have a year’s worth of tourism in an eight-week period.”

Six weeks after the beagle scratched, Oscar returned with Cruiser, a puggle — a cross-breed of a pug and a beagle — to give what I hoped would be the all-clear verdict. Cruiser got to work. I waited, eager for things to get back to normal.

When Cruiser did not scratch I was elated. But then it hit me: there is a new normal. Because even if your home gets a “clean” bill of health, seconds later you can bring one back in. You can burn your old bed, buy a new mattress, destroy books, toys and clothes — but that’s still no guarantee that bedbugs won’t return.

The only way not to bring them home again would be to never go out. But even that’s not foolproof, as a neighbour could have them, and they migrate through walls. So I take precautions. I know what to look for and I’m on the waiting list for a PackTite. Of course, every time I sit in a taxi or on a plane, I’ll worry a little bit. And if I ever got them again? I can’t think about it.