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Business, Environment, STEM

Don’t Let The Bed Bugs Bite: A parasite’s growing resistance to insecticides

Beg-bug-appearance-and-life-cycle_Source-EPA

Bed bug appearance and life cycle            (Source: EPA.gov)

We are a little more than a week away from the official start of the summer solstice which begins on June 20, 2016. The temps are heating up across these United States and, depending on where you live, DEET, Citronella, and other insect repellant products may already be in use at your house and frequented recreation areas. For the past six months, I’ve been tracking activities associated with the Zika virus and its culprit carriers, the Aedes aegypti and albopictus mosquitoes. However, another parasitic insect – the bed bug – has my ire this week.

Like mosquitoes, bed bugs are human parasites and have been around for thousands of years. According to Wikipedia, bed bugs were mostly eradicated in the developing world and in the U.S. in the early 1940s mostly through the use of DDT and Malathion. However, they have increased in prevalence since about the mid-1990s. The likely causes given are pesticide resistance, governmental bans on effective pesticides (e.g. DDT and Malathion), and international travel. Along with the increased infestation of human habitats, bed bug bites and related conditions have also been on the rise.

If you live in an apartment or share at least one wall with another dwelling, know this: if your neighbor has bed bugs, their unwelcome guests may also decide to pay you a visit. However, they won’t be knocking on the door. They travel through walls, floor boards, cracks and crevices, and will catch a ride on just about anything. Bed bugs are night feeders and are attracted to carbon dioxide, CO2, which humans expel with every breath. These blood suckers may also bite our pets, but they prefer humans to cats and dogs any day.

Researchers at New Mexico State University reported earlier this year that bed bugs in the U.S. have developed resistance to neonicotinoids, the most widely used insecticide in the world. [Ref 1] Studies show the blood sucking insects in Cincinnati and Michigan had “dramatic levels” of immunity to regular doses of the chemicals. To kill these bugs required concentrations of up to 1,000x larger than needed to eliminate non-resistant creatures.

Thanks to the increase in the global human population and the rapid expansion of international travel, the flat bodied bed bug has become a source of considerable irritation in hotel rooms all over the world. That’s my beef! I now need to not only worry about what I am packing for my next trip, but also what I may be bringing home after spending one or more nights away.

Infestations have also spread to homes and offices and the bugs are extremely hard to get rid of once they gain a foothold; they can survive for up to a year without feeding. One, single fertilized female can infect an entire apartment building. It takes only one! According to Pest World, bed bugs have been found in every state, and that has been true for the last 10 years, if not longer. Bed bugs do not discriminate according to neighborhood or ZIP code. A number of 5-Star hotels and resorts have reported bed bug infestation problems.

bedbug-hearingaScientists in Australia discovered that in the battle between bed bugs and humans, some of the insects wield thicker exoskeletons, making them more resistant to insecticide. [Ref 2] Using a scanning electron microscope, the scientists measured the cuticles, or exoskeletons, of bugs from different groups. They found that the more resistant the bug, the thicker its shell. In fact, the pests in the “resistant” category had cuticles that were 16 percent thicker than the bugs in the “intolerant” group. The resistant bugs’ cuticles were also thicker than the bugs from the laboratory strain that was so susceptible to the insecticide.

“The new findings reveal that one way bed bugs beat insecticides is by developing a thicker skin,” says David Lilly, a PhD candidate at the University of Sydney and the study’s first author.  Lilly added that research might be able to help scientists understand how to better fight the parasites.

“If we understand the biological mechanisms bed bugs use to beat insecticides, we may be able to spot a chink in their armor that we can exploit with new strategies,” he said.

Improved understanding of how bed bugs tolerate insecticides could help researchers design toxins that aim at those defenses. The next generation of bed bug sprays may be a cocktail of chemicals that includes inhibitors to cripple the insect’s detox mechanisms. “Work is already underway to look for inhibitors,” say Subba Reddy Palli, a professor of entomology and one of the researchers involved in a study at the University of Kentucky.

Until then, here are some non-pesticide options to get rid of bed bugs:

  • Heat: studies show that 122+ degrees Fahrenheit (50 degrees Celsius), is a lethal temperature for bedbugs, according to the Mayo Clinic. Your clothes dryer may be your best friend for laundry, small cushions, and similar items (assuming that they can survive the drying cycle and won’t damage the dryer).
  • Extreme Cold: Similar to heat, freezing infested items for a few days at temperatures below 0 F (-18 C) may also put bedbugs to permanent rest, according to the University of Minnesota.
  • Mattress and box spring encasements: These have proven to be an effective way to proactively guard against bedbugs. If there already is an infestation, encasing the mattress and box spring will entomb the bedbugs and they will eventually die. (Of course one should remove or destroy as many eggs as possible before encasing the mattress and box spring.)
  • Dry Ice Trap: Make a dry ice trap with a dog dish. Put dry ice in a dog dish, and cover the outside of the dish with something the bugs can climb onto, such as a cloth or some paper. They will climb in for the CO2 and then won’t be able to get out.
  • Diatomaceous earth: A naturally occurring pest-fighter that comes from dead algae skeletons or something like that, you can get it online and should use it carefully, but it does work. Thanks to the stuff’s microscopically sharp edges, it’s the equivalent of putting tacks on the deck of a boat to deter pirates.
  • Rubbing alcohol (iso-propyl alcohol): Rubbing alcohol is a solvent and can kill insects by dissolving their cells. Rubbing alcohol is also a desiccant, or drying agent, so it can destroy bed bug eggs by drying them out. In addition, rubbing alcohol repels the bugs, discouraging them from crawling or laying eggs on a surface treated with the substance.

Should you find yourself with a bed bug infestation, exterminators and etymologists recommend a combination of treatments to improve effectiveness and to get a handle on the problem.

Until my next post, “Don’t let the bed bugs bite!

References:

  1. Bed bugs develop resistance to widely used insecticides, by Matt McGrath – Environment correspondent, in BBC News – Science and Environment, January 28, 2016, http://www.bbc.com/news/science-environment-35421742
  2. Bed bugs are getting tougher ‘skin,’ scientists warn, by Rob Verger for Fox News, April 15, 2016, http://www.foxnews.com/science/2016/04/15/bed-bugs-are-getting-tougher-skin-scientists-warn.html
  3. Massive Resistance: Bed Bugs’ Genetic Armor Shields Them from Pesticides, by Marissa Fessenden for Scientific American, March 14, 2013, http://www.scientificamerican.com/article/massive-resistance-bed-bugs/
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About Vi Brown

Vi is principal and CEO of Prophecy Consulting Group, LLC, an Arizona firm that provides business and engineering services to private and public clients. Prior to establishing her consulting practice in 2001, Vi worked with Motorola, Maricopa County Government, Pacific Gas & Electric, CH2M Hill, and Procter & Gamble. As an adjunct faculty member, Vi teaches undergraduate calculus classes and graduate level environmental courses. She is also a professional speaker.

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