Posted on 10/23/2011 7:15:22 AM PDT by PJ-Comix
Until about a decade ago, most people in the United States only knew about bedbugs through the seemingly dated phrase "Sleep tight, don’t let the bedbugs bite." But the bloodsucking parasites, which were largely eradicated by the mid-20th century, have roared back in all 50 states, and the bugs’ evolving resistance to insecticides is part of the reason for their resurgence. A new study gives the most complete picture so far of the adaptations some bedbugs have developed to thwart exterminators’ poisons.
The pesky bugs, it appears, can pump out a stew of enzymes that destroy insecticides, according to the study out this week in the journal PLoS ONE. This newly described neutralizing mechanism is in addition to a mutation, which scientists revealed a few years ago, that alters the structure of bedbugs’ nerve endings and prevents common insecticides from binding to their nerves. Together, these defenses could form a one-two punch that protects bedbugs from exterminators’ chemicals.
"The enzymes we discovered in the context of this paper are essentially the initial line of defense in breaking insecticide down before it reaches the nerve," Zach Adelman, lead author of the paper and an associate professor of entomology at Virginia Tech, says.
To figure out bedbugs’ defenses, Adelman and colleagues started by gathering a sample of bedbugs from Richmond, Va. The Richmond bugs had demonstrated strong resistance to a class of insecticides known as pyrethroids—the agents of choice for exterminators. Pyrethroids paralyze bedbugs by keeping open the sodium channels where nerves meet and communicate with one another. "The nerve will keep firing, and it can’t relax," Adelman explains. The result: paralysis and eventual death.
The researchers also used some bedbugs that had been reared in a lab in Fort Dix, N.J., for decades, and had not been exposed to chemicals. When Adelman’s team blasted both sets of bedbugs with two different pyrethroid insecticides—one called beta-cyfluthrin and another deltamethrin—they found that the Richmond bugs could withstand 111 times the dose of the beta-cyfluthrin insecticide compared with the Fort Dix bugs, and a whopping 5200 times the dose of deltamethrin.
Clearly, the hearty Richmond bugs had adapted some strong defenses. Adelman and company found that the bugs possessed one of the two mutations in genes coding for their sodium channels that researchers had previously seen in populations of New York bedbugs that were also resistant to this class of insecticide. The mutation is analogous to camouflage—it’s as if the insecticides can’t recognize the nerve endings they typically target. Adelson’s group also saw that the Richmond bugs were producing far higher levels of suspected insecticide-busting proteins in the cytochrome P450 monooxygenase and carboxylesterase families.
With these identifications, Subba Reddy Palli, an entomologist at the University of Kentucky, thinks the study will help in bringing bedbugs to heel. "This paper is good progress toward understanding insecticidal resistance," he says.
Now that his team has identified the genetic sequences bedbugs use to make these detoxifying compounds, Adelman says scientists can check populations worldwide to see how far this defensive capability extends. That will be important for establishing surveillance of growing resistance, as well as for creating new strategies for controlling the critters. For example, he says, if it seems that only the Richmond bedbugs have the genetic mutations needed to crank out this particularly powerful cocktail of enzymes, exterminators should engage in an all-out assault to try to wipe out that bedbug population before it spreads.
The arms race against bedbugs and other insects mirrors the battle with bacterial "superbugs" that have developed antibiotic resistance, such as those that cause staph and tuberculosis. Indeed, bedbugs have a long history of developing defenses against our chemical warfare agents. Bedbug "superbugs" first emerged in the 1950s. DDT (which was banned in 1972 because of human health concerns) wiped out most native bedbug populations in the U.S. by 1950. But some bedbugs survived, developing resistance to it, and later, organophosphate insecticides such as malathion.
Now pyrethroids are losing their effectiveness. "We have all these bedbugs we’ve chased from one chemistry to another," Dini Miller, a co-author of the study, an urban-pest management specialist for the state of Virginia, and a professor at Virginia Tech, says.
Yet the identification of bedbugs’ enzymatic countermeasures could ultimately provide exterminators with fresh ammunition. Besides insecticides, exterminators use a range of methods, including cold air, steam, and vacuums. But these repeated treatments can add up to hundreds or even thousands of dollars. Rejiggering conventional insecticides might still do enough damage to keep bedbugs at bay. "We can look at formulating things in new ways and get better penetration into these bedbugs," Miller says.
Down the road, scientists can base next-generation insecticides on chemicals substantially unlike those that bedbugs have already mastered disarming. Adelman says: "We can come back to the bugs and say, ‘We have a chemical you can no longer deal with given your arsenal. Now try this on for size.’"
New offensive weapons can’t come too soon, as the spread of these brownish or reddish bloodsucking insects has residents of heavy-hit urban areas such as New York City on edge. "Bedbugs don’t kill you," Adelman says, "but they can drive you crazy."
Let's see. Bedbugs have been around for MILLIONS of years yet insecticides are a very recent manmade development. So how did the bedbug have sophisticated genes that could resist these insecticides? It is almost like when bedbugs developed millions of years ago, something knew in advance that they would one day in the distant future have to fight off insecticides developed by a species that didn't even exist yet.
I think you might have some sermon material here.
bed bugs, the new plague, is caused by letting middle easterners and illegals into the country....even the well to do ones don’t seem to mind a vermin or 2 in their undies....
Genes don’t ‘know’ about insecticides. You may have one in a million who come up with a mutation that makes them not react to them. They are therefore able to breed versus die. The ones that survive and breed pass on this trait to new generations and so on..
Beat me to it.
Smoke and mirrors to obscure the fact that open borders and the resultant third-word sanitary practices have caused the resurgence of bedbugs in the US.
Sound like evolution in action, more likely.
The bugs more resistant to the insecticide were better able to breed. Same as the hand sanitizers makes for a stronger breed of bacteria, because the ones it doesn't kill become stronger.
I’m sure little dinosaurs flopping around on useless proto-wings for millions of years had a gleam in their eye, too. They just knew.
Due to natural variation in the genetic code, out of billions of bugs, a very small number will have undergone mutations that make them more resistant to insecticides.
These individuals are more likely to survive and reproduce than the non-resistant individuals. Over time the resistance will tend to spread throughout the species.
I actually lived through a bedbug nightmare some years back. I thought I had a rash ... then I finally found one on me and we knew.
I lost all my furniture and bed and carpet and had to wash everything.
The exterminator used a pyrethrin-based spray and it took care of them.
However ... are they resistant to DDT? Because THIS is what they used to use before it was banned, right? I can understand banning it OUTSIDE because it caused bald eagle eggs to have shells that were too thin ... but inside? It seems as though common sense would say, “Ok... DDT works and we’re only going to use it inside... so let’s allow it.”
A bedbug sniffing dog was in my apartment some months ago and yippee...no bugs at all....
...but I also discovered that NOW they have a new heat treatment that let’s you keep your furniture.
That would have been good when I had them.
“... open borders and the resultant third world... caused the resurgence”.
I agree. What is frightening is that people can bring them into their homes more easily than believed. I’ve read that many public library books may have them. I have also read that if you go to a mall for some shopping, place all new clothing items into the dryer immediately when you get home. The little critters aren’t just reserved at hotel/motel rooms.
So can bedbugs become resistant to DDT? BTW, has Zuccotti Park become infested with bedbugs yet? Those filthy sleeping bags would make great homes for them.
“third-word sanitary practices”
No. Bedbugs are not attracted to filth. I got them and I’m clean. All they want is blood.
And ALL travel spreads them around ... so even that businessman from German can bring them over to the Ritz and the next person to sleep in that room can take them home.
On the local news the other night they showed the best treatment for bed bugs was heat. They pipe heat into your house and raise the temperature to 140’ degrees and they are dead.
“BTW, has Zuccotti Park become infested with bedbugs yet? Those filthy sleeping bags would make great homes for them.”
Bedbugs are less of pest than the human parasites.
Of course, if the room hasn't been occupied for some days, the cover will allow the critters to invest the sheets. Best thing is to carry a small bottle of sanitizer that can be sprayed.
In texas, it would be extremely easy to clean up a bedbug infestation in the summer.
On one of the days when it’s already 110*, get a hotel room and clear out all of your kids and pets. Close up the doors and windows and crank the heater all the way up.
Go to a hotel for two days.
Come home, turn on the AC and cool the place down.
Enjoy.
Bedbugs can’t survive in anything hotter than 120* for more than a couple of hours. 140* kills then within minutes.
The reason you let it sit for a couple of days is to make sure all the nooks and crannies are heated up. Don’t let them have a place to hide.
I don’t know if they can become resistant. I just did A LOT of reading when I got them... then I quit once I’d done enough because I didn’t want to dwell on it ... and they were gone.
I read that we had eradicated them in the 50’s because of DDT use.
Or their genes adapted. I often wonder if we plucked someone from the 1860’s rural setting and plopped them in the middle of NYC, how long they could live. I am not talking about physical safety, but about smog, chemicals, processed foods... how would their bodies hold up to what we have gradually become accustomed to by our mother’s eating some more processed than their own mother, and on and on.
I hope this makes sense, not quite sure how to put it.
That’s one of my concerns.
I have to travel a lot for my job so I stay in hotels/motels 2-3 nights a week.
I’m always worried I’m gonna bring some home with me.
(This would be far worse than when we had fleas in the house from our now departed cat.)
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