Biologists were itching to end bedbug scurge

By Jasminee Sahoye

BedbugsHusband and wife biologists have devised the first effective bait and trap for detecting and monitoring bedbug infestations which are expected to be available sometime this year.

Bedbugs are becoming a nuisance not only in low-income housing but also expensive hotels and apartments, and public venues such as stores, movie theatres, libraries and even public transit. The bait and trap are expected to be produced on a commercial basis.

This invention follows the bravery of Simon Fraser University (SFU) biologist Regine Gries, who used her arms to provide a blood meal for more than 1,000 bedbugs each week for five years, while she and her husband, biology professor Gerhard Gries, searched for a way to conquer the global bedbug epidemic.

Working with SFU chemist Robert Britton and a team of students, the couple have finally found the solution – a set of chemical attractants or pheromones that lure the bedbugs into traps and keep them there.

After a series of successful trials in bedbug-infested apartments in Metro Vancouver, they  published their research in December 2014, Bedbug Aggregation Pheromone Finally Identified, in Angewandte Chemie, a general chemistry journal.

They’re working with Victoria-based Contech Enterprises Inc. to develop the first effective and affordable bait and trap for detecting and monitoring bedbug infestations.

“The biggest challenge in dealing with bedbugs is to detect the infestation at an early stage,” says Gerhard, who holds an NSERC-Industrial Research Chair in Multimodal Animal Communication Ecology.

“This trap will help landlords, tenants, and pest-control professionals determine whether premises have a bedbug problem, so that they can treat it quickly. It will also be useful for monitoring the treatment’s effectiveness.”

Over the last two decades the common bedbug (cimex lectularius), once thought eradicated in industrialized countries, has reappeared as a global scourge. And while these blood-sucking pests were previously not considered a carrier of disease, scientists recently discovered they can transmit the pathogen that causes chagas disease, which is prevalent in Central and South America.

The research was funded with a Natural Sciences and Engineering Research Council of Canada industry grant in partnership with Contech Enterprises Inc.

The Gries’ began their research eight years ago when Gerhard, internationally renowned for his pioneering work in chemical and bioacoustic communication between insects, began searching for pheromones that could lure and trap bedbugs.

Regine worked with him, running all of the lab and field experiments and, just as importantly, enduring 180,000 bedbug bites in order to feed the large colony required for their research. She became the unintentional ‘host’ because, unlike Gerhard, she is immune to the bites, suffering only a slight rash instead of the ferocious itching and swelling most suffer.

The Gries and their students initially found a pheromone blend that attracted bedbugs in lab experiments, but not in bedbug-infested apartments. “We realized that a highly unusual component must be missing – one that we couldn’t find using our regular gas chromatographic and mass spectrometric tools,” says Gerhard.

That’s when they teamed up with Britton, an expert in isolating and solving the structure of natural products and synthesizing them in the lab. He used SFU’s state-of-the-art NMR spectrometers to study the infinitesimal amounts of chemicals Regine had isolated from shed bedbug skin, looking for chemical clues as to why the bedbugs find the presence of skin so appealing in a shelter.

It was like looking for a needle in a haystack, they say.

After two years of frustrating false leads, Britton, his students and the Gries duo finally discovered that histamine, a molecule with unusual properties that eluded identification through traditional methods, signals “safe shelter” to bedbugs. Importantly, once in contact with the histamine, the bedbugs stay put whether or not they have recently fed on a human host.

Yet, to everyone’s disbelief, neither histamine alone nor in combination with the previously identified pheromone components effectively attracted and trapped bedbugs in infested apartments. So Regine began analyzing airborne volatile compounds from bedbug faeces as an alternate source of the missing components.

“Although bedbugs don’t usually require serious medical attention, they can cause a great deal of anxiety and restless nights,” said board-certified dermatologist Dr. Seemal R. Desai, FAAD, who maintains a private practice in Plano, Texas, and serves as clinical assistant professor of dermatology at University of Texas Southwestern Medical Center.

Desai recommends looking for the following signs for bed bugs near places where you sleep:

  • If you notice a sweet, musty odor in your sleeping area, there may be a heavy bedbug infestation. Bedbugs produce chemicals to help them communicate, although not everyone will notice the smell.
  • Look carefully at blankets, sheets and mattress pads, mattress and box spring for specks of blood, especially near the seams. They may indicate a bedbug infestation.
  • Bedbugs have a shell they shed. Check for shell-like remains on the mattress, mattress pad or beneath couch cushions.
  • If you see tiny, blackish specks on the bedding, mattress, or headboard, it could be bedbug excrement.
  • After mating, female bedbugs lay white, oval eggs in cracks and crevices. These are small, as a bedbug is only about the size of an apple seed.