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."
They sure are!!! Just be diligent and search, search, search. My husband knows that if he accidentally brought them home, my family would have to visit me on the locked down psych ward. I just don’t like parasites to the point that I took a hot shower right after reading the initial post!!
“A little DDT will beat them back”.
Seems to me that when we used DDT, we had a lot less critters. Got to go now... I’m taking another shower.
The bedbug genes didn’t KNOW about insecticides. That’s not how evolution works.
Spray insecticide on 20 million bedbugs and all of them die, except for a few. Those few bugs survived because they had some genetic difference, some flaw. Lucky hit, nothing more.
It’s taken most of a century for that small colony of lucky bedbugs to spread back into their old range. You see the same thing with disease bacteria, mold, etc. Evolution never stops.
The few that are resistant to the insecticide survive and produce the next generation, and so on until the entire population has that ability.
These bed bugs didn’t “evolve” these defenses over the last couple decades, they already had them encoded in their genes.
The Evolutionists are so dedicated to the primary axiom that they see Evolution in every thing, even in the design of sport cars.
Beat me to it. I’m still waiting to hear one living thing that has been observed to have “evolved” into another species. Then again I’m not into the church of pseudo science, so maybe I’m unworthy.
How hot is the air that comes out of my blow-dryer? If it’s hot enough, couldn’t I just blow-dry the mattress and sheets at the hotel for a few minutes to get rid of any bugs I didn’t see when I checked the sheets and mattress?
What has been done with other species, like the screw worm, is bringing “spent cartridges” (irradiated sterile individuals) into the population; since those species mate once and die, that effectively reduces the bugs’ numbers.
I don’t think a blow-dryer would work. Even if it were hot enough, you’d have to treat every possible location for the right amount of time (a few minutes or more).
Better to use google to get some good tips, here’s one site I found interesting:
http://abcnews.go.com/Travel/tips-avoiding-hotel-bed-bugs-traveling/story?id=11748855
Right here http://bedbugregistry.com/.
Agreed. Bedbugs, along with a myriad of diseases. Oh well! “Our Diversity Is Our Strength!”
I hear ya’. I drive the husband nuts by bringing my spray can of Lysol and spraying the bejapers out of the hotel room.
You can borrow books that are sewn - no metal staples, etc.
Have a collection of ziploc bags. Put each book you borrow into a bag before taking it home.
Run them through the microwave for a minute or two.
A year ago, I’d have fully supported your Kindle choice, but the book prices for the Kindle are getting ridiculous. I’m slowly going back to pulp when the book I want is cheaper that way than the eBook.
In fact, IIRC, other insects crawling around in filth (probably spiders) will control the bedbugs. So the bedbugs do better if they have a monopoly on the clean territory.
Yes, yes, spiders are not technically insects but you get my drift. BBs can’t thrive if other things are eating them.
I’m guessing the fire killed the bugs, but weren’t the springs a bit lumpy to sleep on afterward?
Yeah, lumpy and sooty too. :D
thanks!
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.