Posted on 12/28/2024 4:28:00 PM PST by george76
Scientists mapped genomes of bed bug strains, identifying 729 mutations linked to insecticide resistance, offering insights for improved pest control.
Scientists have successfully mapped near-complete and highly accurate genomes for two strains of bed bugs: one highly susceptible to insecticides and another “superstrain” that is roughly 20,000 times more resistant. This achievement provides the most comprehensive view yet of the genetic mutations behind insecticide resistance. The findings were published in the journal Insects.
While bed bugs are not known to transmit diseases to humans, their bites can cause itchy rashes and secondary infections. Insecticide use, including the now-banned DDT, nearly eradicated bed bug populations by the 1960s, making infestations a rarity. However, over the past two decades, bed bugs have made a global resurgence, largely due to genetic mutations that have rendered them resistant to modern insecticides.
Resistance can develop through various mechanisms, such as producing detoxifying enzymes (metabolic resistance) or evolving thicker protective outer layers that block chemicals (penetration resistance). Previous studies have identified some of the genes and mutations involved in resistance, but the complete genetic picture remained unclear because no prior research had sequenced the entire genomes of resistant strains. This new study fills critical gaps, shedding light on the full spectrum of mutations driving their resilience.
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A research team led by Hidemasa Bono, professor at Hiroshima University’s (HU) Graduate School of Integrated Sciences for Life, mapped genomes of susceptible and resistant bed bug strains from Japan to address this gap. They obtained susceptible strains descended from wild bed bugs (Cimex lectularius) collected 68 years ago in fields at Isahaya City, Nagasaki. Meanwhile, the resistant strains were bred from specimens collected from a Hiroshima City hotel in 2010. Their tests revealed that the resistant samples had 19,859-fold stronger resistance to pyrethroids — the most commonly used insecticide for bed bug control — exceeding levels seen in many previously identified superstrains. All the specimens were provided by Fumakilla Limited, a Japan-based chemical manufacturing company.
Piecing together the genome puzzle..
Sequencing a genome is like assembling a massive jigsaw puzzle, spanning anywhere from about 160,000 to 160 billion pieces. To map the most complete bed bug genomes to date, researchers used the breakthrough method of long-read sequencing, which captures longer stretches of DNA—akin to having entire sections of puzzle pieces put together. Traditional short-read sequencing, by contrast, only covers tiny snippets, often leading to frustrating gaps.
The researchers assembled a near-total picture of the two genomes with just about every piece precisely where it belonged, achieving 97.8% completeness and quality value (QV) of 57.0 for the susceptible strain and 94.9% completeness and QV of 56.9 for the resistant strain. A QV above 30 indicates high-quality sequences with less than 0.1% error rate. Both also surpassed the N50 value of the existing C. lectularius reference genome, Clec2.1, from a previous sequencing effort, meaning there were fewer gaps and more complete sections of the genome puzzle.
Known, new resistance mutations uncovered..
After fully sequencing the genomes, the team identified protein-coding genes, determined their functions, and assessed if they were active through transcriptional analysis. They uncovered 3,938 transcripts with amino acid mismatches. Of these, 729 mutated transcripts were linked to insecticide resistance.
“We determined the genome sequence of insecticide-resistant bed bugs, which exhibited 20,000-fold greater resistance compared to susceptible bed bugs. By comparing the amino acid sequences between the susceptible and resistant bed bugs, we identified 729 transcripts with resistance-specific mutations,” said study first author Kouhei Toga, postdoctoral researcher at the Laboratory of Genome Informatics of HU’s Graduate School of Integrated Sciences for Life.
“These transcripts included genes related to DNA damage response, cell cycle regulation, insulin metabolism, and lysosome functions. This suggests that these molecular pathways may play a role in the development of pyrethroid resistance in bed bugs.”
By drawing on previous insect studies, the researchers confirmed known resistance mutations and discovered new ones that could inform more targeted and effective pest control strategies.
“We identified a large number of genes likely involved in insecticide resistance, many of which have not been previously reported as being associated with resistance in bedbugs. Genome editing of these genes could provide valuable insights into the evolution and mechanisms of insecticide resistance,” Toga said.
“Additionally, this study expands the pool of target genes for monitoring allele distribution and frequency changes, which could contribute significantly to assessing resistance levels in wild populations. This work highlights the potential of genome-wide approaches in understanding insecticide resistance in bed bugs.”
You don’t kill them. You eat them. Big difference.
DDT kills them, but idiots had to ban it.
rendered them resistant to modern insecticides.
“Why Are Bed Bugs So Hard To Kill?”
Dursban was outlawed.
DDT seemed to work just fine until that hack Rachel Carson ruined it.
Temps over 120 degrees kills them.
Does DDT still kill them or are they resistant to it?
Stay out of motels and hotels.
After 50 years, they probably lost resistance to it. It used to work before it was banned.
Put on clothes fresh out of the clothes dryer. Get a few portable heaters, fans and some wireless thermometers.
Go from room to room. Place a wireless thermometer on the floor, one under a mattress/cushion, one inside a sock drawer, one inside a jacket pocket and one on a top shelf in a closet.
Turn the fans on and heat the room until the floor thermometer reads about 130F and keep the heat going several hours. Turn everything off and go to the next room. Keep on going through the house until you've done every room.
Not a bad idea to repeat the process a week or two later.
We need DDT back.
Thank you for the advice.
Like cockroaches and democrats.
Then the Bayer bean counters changed manufacturing and outsourcing to relabel the product as Temprid FX…contact only and no residual or collateral kills.
Current effective product is Apprehend, which a fungus but is only effective below 80F.
“DDT seemed to work just fine until that hack Rachel Carson ruined it.”
And banned by the Nixon stooge Ruckleshouse and his wife (another Jill no less).
Bringing back DDT would save 1.5+ million lives. Malaria was almost eradicated until that lying *itch came out with silent spring and scared first world populations to sacrifice 3rd world lives (mainly children) to the alter of environmentalism.
They are easy to kill. I’ve done it. Twice. In two different homes. Diatomaceous earth. To get them to bathe in it, you have to use their own feeding patterns against them. They were in my 8 year old daughter’s room and bit up her legs. So I put fairly deep plastic containers with D.E. in them under each of the four legs of her bed. I put helpful “ramps” to the containers, so they could easily walk up to them, but then they fell in, and there was no getting out. The D.E. slowly kills them over a number of hours, slicing their shells and they dehydrate and die. After 3 days the dishes were filled and no more were to be counted. Never saw them again. In the 2nd house, the infestation was a bit worse, and I repeated the process, but using homemade CO2 emitters (yeast, sugar and a 2L bottle) with the same D.E. setup. Took a week, but they all died.
Worked for us. Saved thousands of dollars.
Actually, you want the lowest temp from the different thermometers to be about 130F. That provides a margin so that nooks and crannies of baseboards, AC register boxes, etc make it to 120F.
Household electronics seem to be ok. We never lost anything but we did lose a couple of cheap thrift store box fans in the heated rooms. Make sure you uses fans to circulate the heated air in the room.
And put a bedbug free towel under the door(s) of the room being heated.
If your children are picking them up at school, or from friends houses and bringing them into yours, you have a problem that may not be completely solvable, only managed.
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