MONDAY, Sept. 9 (HealthDay News) -- Bedbugs -- tiny, flat
parasites that hide where people sleep -- are notoriously tough to
kill, but scientists say they think they've uncovered new clues
about why these bloodsuckers are so hardy.
It seems that bedbugs have genes that disarm pesticides. Most of
the genes are active in the bugs' outer shells, or cuticles. Some
work to pump poisons away, before they can enter the insect's
bodies. Others genes break the chemicals' molecular bonds,
rendering them harmless.
Scientists at the University of Kentucky discovered the genes by
surveying the entire genomes of 21 different bedbug populations
from cities around the Midwest. It took four years to complete the
They found 14 genes that work in various combinations to thwart
poisons called pyrethroids, the chemicals that have been the
first-line agents against bedbug infestations.
When they blocked those genes, the bedbugs once again became
susceptible to pyrethroid insecticides.
So far, bedbugs are the only insects that have been found to
have these kinds of defenses in their outer cuticle. Other insects,
which feed on plant material, develop defenses to toxins in their
That makes a kind of beautiful sense, said study co-author Subba
Palli, who is a professor of entomology at the University of
Kentucky, in Lexington.
"Bedbugs feed on blood from humans. The only way they're really exposed to insecticides is when we spray them on their bodies or if they walk on the insecticides. That's the reason they may have developed a different way of defending themselves," he said.
Blocking these special genetic defenses in the lab is a
relatively straightforward process. Scientists just inject the bugs
with strands of RNA that interfere with gene expression. It's not
possible to inject RNA into wild bedbugs, of course.
"One big problem is how do we deliver them to the insect? If someone solves that, I think we could have a really good product," to kill bedbugs, Palli said.
The research was published earlier this year in the journal
Scientific Reports. It will also be presented Monday at the
American Chemical Society annual meeting, in Indianapolis.
"I think the work is very interesting, and I think it's at the forefront of bedbug research," said Mark Feldlaufer, an entomologist with the USDA's Agricultural Research Service, in Beltsville, Md.
"They come out at night. They only take five to eight minutes to feed and then they go back to cracks and crevices where they aggregate. Those cracks and crevices might be in your mattress or headboard or things like that," Feldlaufer said. "So when you apply an insecticide, it's tough to get it to where they are."
Hitting them where they live is one problem, said Feldlaufer,
who studies bedbugs but is not part of the new research.
"If they're resistant to many of the chemicals that are used, that's another problem," he added.
So what can a bedbug-wary homeowner do? In an American Chemical
Society news release, lead study author Fang Zhu of Washington
State University recommended common sense measures such as removing
bedroom clutter, frequent vacuuming, washing bed linens in hot
water and heating them in a dryer, and sealing cracks and
For more about bedbugs, visit the
Centers for Disease Control and Prevention.
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