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Why bed bugs are making a comeback

Vox.com logo Vox.com 4/27/2015 Brad Plumer

This digitally-colorized scanning electron micrograph, SEM, revealed some of the ultra structural morphology displayed on the ventral surface of a bedbug, Cimex lectularius. (Media for Medical / Universal Images Group/Getty Images) © Provided by Vox.com This digitally-colorized scanning electron micrograph, SEM, revealed some of the ultra structural morphology displayed on the ventral surface of a bedbug, Cimex lectularius. (Media for Medical / Universal Images Group/Getty Images)

For about 60 years, Americans thought they had vanquished bed bugs forever. They were wrong.

Bed bugs have been an insanity-inducing staple of American life ever since the Mayflower. In 1926, infestations in hotels and apartments were so common that experts couldn't recall a time when they weren't a problem. People absolutely hated being bitten in the night by these tenacious bloodsuckers, but the bugs were seemingly impossible to eradicate.

Then, in 1939, a Swiss chemist named Paul Hermann Muller discovered the pesticide DDT, which proved staggeringly effective at killing insects. And, for decades thereafter, DDT and other chemical pesticides helped keep America's homes and hotels bed bug free.

But it didn't last. Since 2000, a new strain of pesticide-resistant bed bugs has been popping up all around the nation — in 2009, there were 10,000 reported complaints in New York City alone. Apartment dwellers were waking up with mysterious bites and rashes on their skin and finding peppery flakes around their mattresses (bed bug poop). People couldn’t rid themselves of bed bugs no matter how often they did laundry or threw out their mattresses. Once the bugs invaded, it seemed, almost nothing can stop them.

The bed bug invasion is a skin-crawling story recounted in Brooke Borel’s riveting new book, Infested: How the Bed Bug Infiltrated Our Bedroom and Took Over the World(the book was partially funded by the Alfred Sloan Foundation). I called Borel, a science journalist, to hear more about how bed bugs made a comeback, why they’re so tenacious, and whether we might ever get rid of them again.

Brad Plumer: I’d half assumed bed bugs were a very recent phenomenon, so it was fascinating to see that even the ancient Egyptians were trying to cast spells to ward them off.

Brooke Borel: Yeah, one thing that really struck me was the similarities throughout history. When the bed bug resurgence happened in the last 15 years, we had all these newspaper articles saying, oh my god, they’re in the movie theaters, there in this place, in that place. But when I went back and read some of the historical material, that’s always been the case.

You can go back and read descriptions of these old beds with jars around the legs that contained paraffin to ward off bed bugs. And that’s just an old school version of these little traps you can buy today to put under your bed and capture the bugs. It’s just an old story that’s been repeating itself forever.

BP: Now, there was this 60-year period after World War II where we’d vanquished bed bugs. How did that happen?

BB: A big part of that story happened in 1939, when a Swiss chemist [Paul Hermann Muller] discovered the insecticidal properties of DDT. These were the first synthetic insecticides, and they were way more effective than the natural botanicals or elemental poisons we had been using previously.

Most insects had never experienced this type of poison before — and they were very vulnerable to it. So we were able to knock bed bug numbers down. One key thing about DDT is that it leaves a residue on surfaces for a long time, months, maybe even a year. That was especially effective against bed bugs, because they hide in cracks either during the day or whenever you’re not there to provide food, they hide. Earlier sprays might have dissipated or not gotten down into the cracks where the bed bugs were. But DDT leaves a residue, and bed bugs would walk through it in order to come eat.

There might have been other factors in knocking down bed bug numbers too. Some experts point to different housekeeping practices that emerged after World War II — people were using vacuum cleaners more, and so on. That’s more anecdotal than anything else. Or in the United Kingdom, they were able to reduce bed bug numbers before the war, in the 1930s, because they completely tore down all these tenement buildings and rebuilt them.

BP: So how did bed bugs make a comeback? It wasn't simply because we banned DDT in the 1970s, was it?

BB: No. Some people still say the only reason we have bed bugs now is because we banned DDT [after concerns about its threat to wildlife]. But that’s just not true. We would’ve had this problem regardless of the ban. The bigger problem is that bed bugs were becoming resistant to DDT, and that was starting to happen way before the ban occurred.

DDT and other pesticides work on the nervous system of insects — often by screwing with their ion channels and leaving them open so that it fries the nervous system. These new resistant bed bugs were essentially able to close that channel again, so that didn’t happen.

BP: Okay, so some bed bugs evolved this resistance to DDT and other pesticides. But how did they become so widespread?

BB: The idea is that pockets of resistant bed bugs evolved somewhere in the world, probably in more than one place. And then in the 1980s and 1990s, you have this huge increase in travel. Air travel definitely increased both domestically and internationally after it got cheaper through the deregulation of airlines in the United States and a set of new treaties in the 1990s. So that probably helped spread these resistant bed bugs.

The question we still don’t know is where, exactly, the resistant bed bugs came from. Some researchers think it may have been many places all at once. Other researchers think it started with just one hot spot or a couple hot spots, and then got spread around.

One hypothesis is that it started in Eastern Europe. There’s also an idea that resistant bed bugs came from somewhere in Africa because of the use of pyrethroid-impregnated mosquito nets. I think that’s pretty compelling too. [Note: pyrethroids are another pesticide that works by preventing the sodium channels of insects from closing.]

BP: So what is it that makes bed bugs so tenacious and hard to kill? Is it just this pesticide resistance?

BB: I think it’s the combination of so many things. They are cryptic insects and they hide during the day. They are not necessarily nocturnal, but they do go into hiding, which makes it hard to see them. They’re not invisible, but they’re hard to detect with the human eye.

But the resistance is definitely a problem. Bed bugs have what’s called a knockdown resistance — it’s the same genetic mutation that gives them resistance to DDT. But there are other forms of resistance, too. There are enzymes called P450s that break down the insecticides more quickly, so that they’re not as toxic to insects. There’s also research that some of these insects might be growing thicker exoskeletons, which makes it tougher for insecticides to penetrate.

There are other factors, too. Some people aren’t allergic to them, so they might catch the problem only far later when it’s become a really bad infestation. Also, they can spread very easily in cities — because to get rid of them you have to work with other people sharing living space or sharing walls with. That can be incredibly difficult.

There’s also a lot of shame involved in having bed bugs. And it’s expensive to get rid of them. So people might try to hide the fact that they have an infestation —and then it gets worse and worse, and then it’s spilling over to neighbors as well. There’s this whole social dimension.

BP: You mention in the book that you’ve experienced bed bug attacks several times. What is it that makes them so hellish?

BB: Before I answer that, I will say, the reason I think I’ve encountered them so often is that I’m really, really allergic. Like in this Chicago hotel [where, in the book, she gets bitten], I was staying with a friend, and he didn’t get any bites. But he just might not have been allergic. A lot of people might sleep in beds with bed bugs and not notice at all.

Now, on the psychological part, probably any psychiatrist who has dealt with someone with bed bugs will tell you the same thing.

There is something about the fact that your bedroom is your sanctuary, and you’re also the most vulnerable in your bed, because you’re sleeping. You really don’t get much more vulnerable than that, you’re literally paralyzed. And to have something that’s hiding that you can’t see that comes out and attacks you in your sanctuary, that is just really psychological difficult.

BP: Why can’t we just invent a new chemical or insecticide to kill these bed bugs?

BB: It’s a pipeline problem, just like the discovery of antibiotics or other drugs or other insecticides. It gets increasingly difficult to find the right chemicals and figure out whether they’re safe enough for us to use.

Bed bugs are especially difficult, because they live in our bedroom, and that’s one of the places we want to be especially careful when it comes to applying insecticides. So that’s part of the issue there.

It’s also incredibly expensive to research and develop the ingredients that go into an insecticide. The estimate for pesticides is something like $256 million per active ingredient over a period of around a decade. And even though bed bugs seem like a big problem, and it seems like you could make money making a bed bug insecticide, it’s not anything compared to the amount of insecticides we use in agriculture. So it’s not necessarily a major focus of the chemical companies.

BP: So what are the best ideas experts have come up with for getting rid of bed bugs?

BB: Keep in mind that there’s a caveat for anything I could possibly say here. I do think that heat treatments are very helpful — bed bugs don’t seem to be developing a resistance to those. Basically you heat a room to a certain temperature, and it kills the bugs and the eggs, without chemicals involved.

The caveats, though, are that this is expensive, it can cost thousands of dollars. It’s not necessarily the best approach in an apartment building, because if you only treat one unit, and the neighbors have bed bugs and aren’t taking care of the problem, then you’ve probably wasted that money, because the bed bugs are going to come back.

Then the other problem is that people have been hearing about this and trying to do their own heat treatments. They’ll use a space heater or something inappropriate and their houses will catch fire. So it’s not for everyone.

BP: You did a lot of reporting on the multimillion-dollar industry that’s sprung up around controlling bed bugs. And you seemed to come away skeptical. Why?

BB: I think that,especially in the United States, we’re still in this Wild West era for bedbug control. There are some people who really believe in their products, but their products are bad. You could walk into a store and see a product that says: "Kills bed bugs on contact," To a consumer, that sounds great, but all that means is that you have to spray it directly on the bed bug. But bed bugs are often hiding, so that’s not necessarily helpful.

There’s a lot of opportunity to take advantage of people’s fears. Even the Federal Trade Commission has caught wind of this, they had two cases against two companies against products advertised as all-natural contact killers, and they said, you can’t advertise like this.

BP: Having written the book, what advice would you give for someone who discovered bed bugs in their room?

BB: As far as the psychological stuff goes, I would say it’s going to suck — but don’t panic!

In every city and state, there’s a hodgepodge of rules for who’s responsible financially for a bed bug infestation. So the first step is getting educated on that. If you do rent, your landlord may be legally required to pay for bed bugs treatments.

As far as actual treatments go… I have a little section in the book where I say what I would do. It’s not going to be right for every person. Because I’m so allergic, I’d know pretty quickly if I did have bed bugs. So before calling an exterminator, I would try to do all my laundry, do a search and see if I could find the bed bugs and where they’re coming from, clean up, and then see if I was still getting bites. But that’s mainly because I’d be able to tell easily if I was still getting bitten.

But that’s not necessarily right for everyone, and I don’t recommend that for each person. For the most part, I’d suggest people call a professional — though it can be daunting to figure out who’s good.

BP: Do we know if the bed bug problem is getting worse in the United States?

BB: It’s a little tough to say. In general, I don’t think the problem’s getting better, I don’t think there are fewer bugs. I do think that people are not freaking out about them as much and more knowledgeable on how to deal with them.

There’s a survey by the National Pest Management Association, where they interview pest-control people from all over the world and ask how many bed bug cases in the last year. And those numbers have continued to rise. Then again, that’s an industry group and they’ve been making money out of this.

It also really depends on the city. I’m working on an essay about bed bugs in New York City, where numbers show that 311 calls about bed bugs are going down, but those numbers can be deceiving [since a lot of people don’t necessarily make 311 calls when they have bed bugs].

BP: You interviewed a lot of scientists for the book — I loved all the pictures of researchers who raise bed bugs for study by feeding them on their own arms.

BB: Some people still do that, though for a lot of these bed bug research labs, they have way too many bugs to be able to do that. One of the fascinating things I learned was that it took a long time for scientists to figure out how best to keep bed bugs alive in the lab, given that they’re so hard to kill in the wild.

This interview has been lightly edited for length and clarity.

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