Bedbugs are back with a vengeance

Bedbugs have staged a global resurgence in the past two decades after being nearly eradicated in many regions.
Bedbugs have staged a global resurgence in the past two decades after being nearly eradicated in many regions.PHOTO: REUTERS

The good news is: Scientists have identified genes linked to their insecticide resistance

WASHINGTON • Bedbugs, which emerge from their hiding places at night driven to slake their thirst for human blood, have staged a global resurgence in the past two decades after being nearly eradicated in many regions, but scientists have unveiled a complete genetic map of the insects that could guide efforts to foil the resilient parasite.

The tiny, bloodthirsty critters have been biting people for thousands of years. They have become genetically wired to resist pesticides, the experts said on Tuesday in a pair of studies published in science journal Nature Communications.

"Bedbugs are now very widespread in most major cities around the world, and they have increasingly become resistant to insecticides, making them harder to control," said entomologist Louis Sorkin from the American Museum of Natural History in New York.

In the first study, scientists at the museum and Cornell University in New York assembled the first complete genome of the bedbug in all six stages of its life from infancy to adulthood. The genome is the genetic blueprint of every organism.

The scientists identified an array of genes, including those responsible for their insecticide resistance.

These genetic traits may present vulnerabilities that could be exploited with future insecticides.

The genome also harbours numerous genes that originated in bacteria, including one that helps bedbugs metabolise vitamin B. This indicates antibiotics that target bacteria beneficial to bedbugs could be used to control the insects.

"This is an enormous new tool for researchers interested in controlling this pest," said Mr George Amato, director of the Sackler Institute for Comparative Genomics at the museum.

But what they found will also strike fear into the heart of the toughest pest controller. "Today, a very high percentage of bedbugs have genetic mutations that make them resistant to the insecticides that were commonly used to battle these urban pests," said Dr Sorkin, who is one of the study authors.

The troublesome critters have a multitude of genes that render pesticides increasingly ineffective. This "makes the control of bedbugs extremely labour-intensive", he said.

The researchers did discover one bright spot: Some genes linked to pesticide resistance are "expressed only after the bedbug first drinks blood". "This suggests that bedbugs are likely most vulnerable during the first nymph stage, potentially making it a good target for future insecticides," the museum said in a statement.

In the second study, researchers at the University of Cincinnati and at Virginia Tech found that bedbugs have "cuticles" that can stop poison entering their bodies and detoxifying enzymes.

Scientists also found that bedbugs use a series of salivary proteins to suck blood repeatedly on the same person without inflicting pain.

In 2010, an outbreak in New York City saw the bugs invade high-end apartment buildings, hotels, and even clothing stores like lingerie outlet Victoria's Secret.

REUTERS, AGENCE FRANCE-PRESSE

A version of this article appeared in the print edition of The Straits Times on February 04, 2016, with the headline 'Bedbugs are back with a vengeance'. Print Edition | Subscribe