Why the Bed Bugs Keep Biting: New Research
About 50 years ago, bed bugs had nearly disappeared from the United States. But now the miniscule insects are back, and they keep on biting. Why have they reemerged? Scientists at the American Society of Tropical Medicine and Hygiene (ASTMH) report on new research to help explain why “don’t let the bed bugs bite” is such a challenge.
Bed bugs are a hardy breed
Bed bugs have been around for millennia: even the pharaohs of Egypt appear to have dealt with the pests. And they are pests: the common bed bug (Cimex lectularius) is a blood-sucking insect that can cause intense itching and inflammation wherever they bit you. Some of that bite can be in the pocketbook, as attempts to eliminate these creatures, once they infiltrate your home or business, can be very expensive.
At the recent ASTMH annual meeting, researchers discussed reasons why bed bugs have returned and are such a nuisance. One reason is that they are hardy and can inbreed without jeopardizing their chances of producing viable, healthy offspring, which means they can quickly proliferate.
This factor was explored by researchers at North Carolina State University, who conducted two studies on apartment buildings. They discovered that the bed bugs were very closely related within each building, which indicates the bug infestations began with a very small number of bugs.
According to Coby Schal, PhD, one of the investigators, while inbreeding in many other organisms can cause mutations drastic enough to finish off a population, bed bugs are different. Bed bugs can inbreed without problem, as “brothers and sisters can then mate with each other, exponentially expanding the population.” Cockroaches have this ability as well.
Another reason for the return of bed bugs is they have developed resistance to the insecticide—pyrethroids--that once was more effective in controlling them. There may be some promising news on this front, however.
At the University of Kentucky, Ken Haynes, PhD, an entomologist, and his team have been researching certain enzymes in bed bugs that are involved with a system that breaks down the insecticides before they reach their target. Scientists may be able to neutralize the factor that makes bed bugs resistant to pyrethroids.
Also in the works are ways to more effectively attract and trap bed bugs. Rajeev Vaidyanathan, PhD, associate director of Vector Biology and Zoonotic Disease at SRI International, and his team have isolated previously unidentified bed bug compounds that could be used to draw the bugs into a trap.
One big reason why bed bugs may be here to stay for a while concerns lifestyle. According to Vaidyanathan, the current bed bug problem didn’t appear overnight, and it has much to do with population. “We have the highest concentration in the history of our species of humans living in cities,” he noted.
Bed bugs don’t fly; they nest, and “so our own population density has helped them to thrive,” he said, especially in apartment buildings, hotels, motels, and urban areas. Other factors contributing to the current bed bug problem include domestic and international travel, as bed bugs can come in from overseas; and industrial poultry farming, because bed bugs feed on chickens.
If we don’t want the bed bugs to bite, we have to stay one step ahead of them, according to Peter H. Hotez, MD, PhD, president of ASTMH. “Bed bugs have shown the ability to resurge in great numbers once our vigilance wanes. To stay one step ahead of bed bugs and other parasitic organisms, we need to sustain investment in research for new tools.”
Picture credit: Wikimedia Commons