Then there is the problem of paying for the research. While dozens of labs now work on the basic science of bed bugs worldwide, funding remains low in part because bed bugs are not known to spread disease.
Finally, there is the problem of insecticide resistance. Even DDT, the supposed miracle cure, wasn’t immune to this. Five years after the pesticide was in widespread use in the US, DDT-resistant bed bugs popped up in Hawaii; in the 1950s and 1960s, resistant strains were found elsewhere in the US and in Japan, Korea, Iran, Israel and French Guiana, to name a few.
No chemical insecticide is immune to resistance, particularly if it is overused. Today, roughly 90% of bed bugs have a genetic mutation that makes them resistant to pyrethroids, a class of insecticides commonly used for bed bugs that work in a similar way to DDT.
So, chemicals are not the sole answer. Neither, it seems, are any other options when used alone. “There is no silver bullet,” says Michael Potter, an entomologist from the University of Kentucky. Still, chemicals and other tactics can be used in an integrated pest management strategy, where they are sometimes used sparingly along with heat treatments (bed bugs die at 45C), desiccants such as silica gel and diatomaceous earth that fatally dry the bugs out, or vacuuming and getting rid of clutter.
Biological tactics are emerging as another possible option. Insect growth regulators, or IGRs, are chemicals that prevent bed bugs from completing their lifecycle, stunting their growth so they can’t reproduce. But, IGRs are slow-acting, and the bugs will still bite even if they can’t breed. On the horizon, perhaps, are genetically modified versions of symbiotic bacteria that live in the insect’s gut, including Wolbachia, which may be exploited for pest management. Or, the bugs’ pheromones, which tell them where to go and who to mate with, may also be reengineered and used against them.
In the meantime, public awareness measures can keep bed bugs from spreading. Good practices include: checking hotel room beds before unpacking, being mindful of belongings like a coat draped carelessly on an unknown couch, washing clothing in hot water and vacuuming suitcases after travelling, and avoiding discarded furniture on the street. Some experts also recommend sealing mattresses and box springs in encasements specifically intended to keep away bed bugs, which may make the bed easier to treat and could save it from permanent damage.
These combined efforts have knocked down infestations in some areas, says Boase, particularly among high-end hotels and the rich. Both can afford to throw money at the problem. Right now, he adds, the most severe infestations in the UK are in low-income housing – not because poor people are more apt to get them, but because they are less likely to be able to afford the treatments. The US has a similar problem. Better control will depend on cheaper, more efficient options entering the market.
“I feel that it is possible to bring infestation levels down in that residual housing area, but we don’t have the tools of infrastructure to support it,” says Boase. Then again, he says, “we’ve never had [total] eradication before.” But, with cheaper tools, we may be able to knock bed bug levels back down everywhere. Or at least, he adds, “we love to think we can.”
* Many people write “bedbugs”, but entomologists use two words when describing Cimex lectularius, because it is a “true bug” (Hemiptera). Entomologists always use two words for insects that are true to the common name they have – so for example, house fly is two words because those are actually flies, but butterfly is one word because they aren’t flies.