Nobody likes bedbugs. Let’s rephrase that—everyone hates bedbugs. They attack you when you’re sleeping, and they feed on your blood. What could be creepier?

Their bites cause itchiness, sometimes so extreme that you hurt your skin scratching…and all that discomfort can make it pretty hard to get a good night’s sleep. The only good news has been the oft-repeated official statement that bedbugs are not known to cause any human disease.

Now a new study suggests that this statement may not be true. It’s not that these nasty critters harbor infectious viruses or bacteria that can make people sick. But they do leave behind very large amounts of a substance that may cause allergic reactions and asthma episodes in people—histamine.

You’ve heard of histamine. It’s what your own body produces when you are having an allergic reaction. Histamine causes itching, and high histamine levels in the air around us could trigger asthma attacks and other respiratory problems. But that hasn’t been studied much because it wasn’t believed to be a common phenomenon.

Enter bedbugs. They defecate large amounts of histamine, researchers have recently discovered. That’s bad enough. But when researchers at North Carolina State University investigated 14 homes that had had bedbug infestations and compared them with 15 homes that had never had bedbugs, they discovered something disturbing—histamine remained behind long after the bugs were gone.

Shocking finding: Even three months after homes had their bedbugs eradicated with insecticides and high-heat treatments—the standard approaches to kill the bugs—they contained histamine levels 20 times higher than in never-infested homes.

PROTECTING YOURSELF FROM BEDBUGS

While it’s not a health emergency, the emerging evidence that high levels of histamine may be a bedbug health risk is concerning enough that anyone who has had a bedbug infestation should take precautions, according to Zachary C. DeVries, PhD, the postdoctoral researcher who led the study. Early detection can make a big difference. If caught early, a bedbug infestation is much easier to manage and eradicate than when the number of bugs has already grown large.

Recommendations from Dr. DeVries…

  • Learn to recognize signs of bedbugs such as rusty or reddish stains on bedclothes or mattresses. For more details, see the Environmental Protection Agency’s article “How to Find Bed Bugs.”
  • When you’ve been traveling, look closely at your luggage and clothing as soon as you return.
  • As soon as you think you may have bedbugs, contact a pest-management professional. Bedbugs are pretty difficult to eradicate—most are resistant to pesticides, and even when you heat their spaces, they can disperse and survive. It’s best to leave the job to trained and licensed professionals.

REMOVING HISTAMINE

For homes that have had an infestation, removing histamine as much as possible is the goal. Unfortunately, research into this area is still so new that there aren’t any proven methods to do this yet. Future research will test an approach that has been shown to dramatically reduce allergens left behind by cockroaches—a deep professional-type cleaning.

You can do this yourself with a vacuum cleaner that includes a HEPA filter (so the histamine is less likely to simply pass through the machine and become airborne) or hire a professional service that uses one. (For tips on buying a HEPA vacuum, see the Bottom Line article, “How an Air-Quality Expert Protects His Own Home”.)

What needs to be done by you or a professional…

  • Vacuum not only all hard-surface floors but also walls and ceilings.
  • Wipe down all these surfaces with diluted or mild detergent on cotton cloths—which are frequently changed as you clean.
  • Vacuum and then shampoo all rugs and carpeting.
  • Wash bedspreads, blankets, sheets and pillowcases with detergent at the hottest temperature your washing machine allows. Dry-clean items too large for your washing machine.
  • Put allergen-proof covers on all mattresses, box springs and pillows.

Having a professional do all this work in a typical home requires about 12 to 16 person-hours of work in addition to the primary cost of bug eradication. The cost of the cleaning varies based on the extent of the infestation and other factors but typically ranges between $1,000 and $1,500 plus the cost of mattress and box spring covers at about $40 each. But it may be what’s needed to reduce histamine to a safe level.

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