Bedbug War Continues; Scientists Study Bug Genome for Weaknesses
Thursday, January 20, 2011
As the war on bedbugs wears on, scientists try to understand the
invasive pests so they can kill the suckers.
Now, Ohio State University researchers have conducted the first
genetic study to identify pesticide-resistant genes the bugs carry.
It may lead to new ways of controlling the bugs in the future.
"Right now, these studies are still preliminary and only
scratching the surface of the bedbug genome," said Omprakash
Mittapalli, Ph.D., assistant professor of entomology at Ohio
Agricultural and Development Center and corresponding author of the
study. "But bedbugs could be a lot more complicated than previously
Mittapalli and his team analyzed laboratory-reared bedbugs
vulnerable to insecticides, and compared them to pesticide-exposed
bedbugs found in a local apartment in 2009 and 2010. Researchers
identified more than 35,000 expressed sequence tags, tiny portions
of a gene that can be used to help identify unknown genes and map
their positions within the genome.
"The genetic bases for these genes could enable us to formulate
newer development strategies that may be more effective than what
we have right now," said Mittapalli. "But a lot more studies need
to be done, not only to identify candidate genes, but also to get a
better understanding of the biology of the insect."
The study, published in the journal PLoS ONE, found that there
were differences in a gene, known as CYP9, between the bedbugs
exposed to pesticides and the non-exposed bedbugs.
In other words, scientists say bedbugs may be genetically
resistant to the pesticides currently used to get rid of them.
"If we can suppress the expression of that gene and see if
bedbugs are still able to overcome the pesticide, then we'll be
able to see that that gene is involved in overcoming pesticide
resistance," said Mittapalli.
Jim Fredericks, director of technical services at the National Pest
Management Association, said that the preliminary genetic
findings are an important step in the total bedbug extermination
"Bedbug research came to a standstill about 40 years ago when
people thought that bedbugs were gone, so the basic biology in
terms of today's standards has never been investigated," said
Fredericks. "By looking at the genomics of the bug, we start to get
a better picture of how these things work, especially in terms of
And in a press release, Mittapalli said that pinpointing such
defense mechanisms and the associated genes could lead to the
development of novel methods of control that are more
Bedbugs are flightless, nocturnal parasitic insects that were
first noticed in the United States in the early 1700s. They
afflicted Americans until World War II, when the extensive use of
DDT wiped out most of the pests.
But when DDT was banned, the bedbugs came marching back in. Over
the past decade, almost every continent has recorded bedbug
infestation, with an estimated 100 to 500 percent annual increase.
The bedbug plague has forced people to spend billions of dollars on
treatments. And the pests have been known to resurface in homes and
buildings weeks or months after extermination.
Scientists say the banning of DDT is just part of the reason.
They also cite greater foreign travel, more frequent exchange of
second-hand furniture and clothing and the bugs' increasing
resistance to pesticides.
While the bugs do not transmit disease, people allergic to
bedbug bites can experience itching, burning or dermatitis. A
bedbug infestation can also cause anxiety, insomnia or worsen an
existing mental health condition.
For now, Fredericks said that bedbug infestations are dealt with
on a case-by-case basis, but the pest management can include
fumigation, steaming and vacuuming infested areas, and a whole-room
heat mechanism, in which the temperature in an infested room is
raised above 120 degrees. That's lethal for the bugs and their
Missy Henriksen, vice president of public affairs for the NPMA,
said that the overall risk of getting bedbugs is still small. And
bedbug infestaton has nothing to do with social status.
"There is this social stigma incorrectly associated with
bedbugs," said Henriksen. "Bedbugs will come into a clean
environment just as easily as a dirty environment. And, while
people should practice protective to avoid bedbugs, it's through no
fault of their own if they get them."
While it's not the golden ticket, Henriksen said vigilance is
key when trying to prevent bedbugs. She gave a few key
recommendations to prevent bedbugs from living with you.
When trying on clothes in a store, be sure to inspect the
clothes before putting them on, and place your purse and shopping
bags on a hook, not the floor. Unfortunately for those who love a
second-hand unique find, don't bring home furniture left curbside.
If you do buy second-hand goods, make sure you know their
When traveling, keep your suitcase off the floor, and when
returning home, inspect and wash your clothes in hot water.
"It doesn't matter if it's a five-star resort, you have to be
careful," said Henriksen.
And in the meantime, as we all try and prevent bedbugs from
hitchhiking their way into our homes, scientists will continue to
work to understand the inner workings of the insect.
"We're interested in effective and safe treatments that are
approved by the EPA, along with continued research, basic biology
and applied biology of bedbugs," said Fredericks. "In the meantime,
vigilance is an important part of the process."