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How Bed Bugs Outsmart Insecticides

"Sleep tight, don't let the bedbugs bite," used to be a phrase without much meaning. Kids chanted it at bedtime with smiles and giggles.

Lately, few people are smiling when it comes to bed bugs. That saying is haunting grownups and the sentiment has gained new meaning for many people.

They're Back

Bed bugs, once nearly eradicated in most big cities, have made a big comeback recently, especially in urban centers throughout the world... and that is not good news. Bed bugs don't pass on disease, but these greedy little pests suck... your blood! And lots of it.

Some infants, who sleep in infested homes, have been found to be anemic due to the amounts of blood these pests take. Older kids and adults can break out in welts — or worse — from allergic reactions to the bites.

Law suits are being filed due to bed bug bites. Landlords and tenants have added bed bugs to the list of things to fight over. The hospitality industry in many major tourist destinations such as London, Sydney and New York City is at war with these pests who may disturb the sleep of guests — even in some of the poshest hotels.

Bed Bug Basics

There are several kinds of bed bugs but the one best adapted to the human environment is known in Latin as Cimex (“a bug”) lectularius (“lying down at home”). Another, the tropical bed bug, Cimex hemipterus, has been found more recently in urban areas. The Eastern bat bed bug, Cimex adjunctus, travels into homes on the bodies of the bats they feed on.

These nocturnal pests feed about once every five to 10 days but are not thought to spread disease. They are drawn to the carbon dioxide you exhale and the warmth of your sleeping body. They use two tubes, one to inject an anticoagulant and mild anesthetic, the other to suck blood.

Bedbugs live up to four months and one female will produce about 345 eggs during her lifespan. It only takes five feedings for the newly hatched bed bug to begin adding to the population.

Despite the name, they are not just found in beds. They like a place that's warm to call home. They can enter through any tiny crack in a wall. Phone jacks and electrical outlets are favorite nesting places.

Bed Bugs Through Time and Space

One problem with the spread of bedbugs our modern ability to travel from place to place with ease. Bed bugs hitch rides on clothing and other items. These insects do not fly but they can crawl from a passenger sleeping in an airplane seat to the next passenger. They can be passed by contact with infected clothing on the subway, Metro or the Tube. Sitting on a bus or taxi seat where a bedbug has been left behind can mean you are infesting the room where you are staying. Because of their love of travel, many of the best hotels are fighting to keep bed bugs under control.

Cavemen, Romans and medieval nobility knew the bite of the bed bug. They were a major problem on passenger ships during the late 19th and early 20th century. Bed bugs traveled to the Americas with the earliest European visitors and emigrated to Australia on the ships that carried the early settlers from European ports.

When DDT was introduced in the 1950s, the problem of bed beg infestations became less frequent. Because of environmental concerns, DDT was banned in the 1970’s. Bed bugs began to reappear but pyrethroid insecticides were developed that were as effective as DDT.

In the past decade, levels of bed bug infestations have begun to rise again. In many urban areas, they have reached epidemic levels.

Pesticide Resistant Bugs

In the first study to explain the failure to control certain bed bug populations, toxicologists at the University of Massachusetts Amherst and Korea’s Seoul National University show that some of these nocturnal blood suckers have developed resistance to pyrethroid insecticides, in particular deltamethrin, that attack their nervous systems.

The study by senior researcher John Clark and colleagues in a recent issue of the Journal of Medical Entomology revealed that these pests have evolved to outsmart the latest generation of chemicals used to control them since DDT was banned.

Mutations For Survival Mean Pesticide Resistant Bugs

This research found that bed bugs in New York City have acquired mutations in their nerve cells, which blunt the neurotoxic effect of the pyrethroid toxins used against them. The mutations affect sodium channels (resembling pores) in the neurons’ outer membrane, where electrical nerve impulses are produced.

In the past, these nervous system poisons could effectively paralyze and kill the bugs, but this is no longer always the case. They found that resistance was not due to the increased breakdown of deltamethrin (enzymatic metabolism) by the resistant bed bugs but appeared to be due to an insensitive nervous system. Clark and colleagues found that these pores in New York City bed bugs are now as much as 264 times more resistant to deltamethrin. This means that even if treated, New York City bed bugs go on to suck blood from unsuspecting sleepers for many more nights.

The researchers are not sure how widely this resistance has spread. They don't know whether the bugs that infest hotels, apartment buildings and homes in places other than New York City have developed the same type of immunity to chemical control. But as Clark states, “This type of pyrethroid resistance is common in many pest insects and the failure of the pyrethroids to control bed bug populations across the United States and elsewhere indicates that resistance is already widespread.”

Treatment Options

Most researchers and experts warn that trying to get rid of bed bugs without using professional exterminators may just make the problem worse. While some pesticides seem to be getting less effective there are still effective methods to eliminate bed bugs. Bed bugs have not shown resistance to a relatively new material, Phantom® (chlorfenapyr). However, chlorfenapyr may require ten days kill the bugs. During this ten-day period it is important to realize that the bugs may still be active and females may wander and deposit viable eggs in other locations.

If you are looking for a non-pesticide option to get rid of these pests, vacuuming, steam and freezing are some techniques that have has limited success.

According to a Pennsylvania State University statement updated in 2007, "Inorganic materials such as silica gel, boric acid, and diatomaceous earth will provide long term control, provided they are used in an environment with low humidity. These inorganic materials have very low repellency, a long residual life, and can provide good control if thoroughly applied to cracks and crevices. However, they are typically white in color and may leave the surface of items with an undesirable film unless they are carefully applied."

Silica gel, boric acid, or diatomaceous earth are very unhealthy to breathe in and some can cause eye irritation. Be sure to cover any matress treated with a plastic mattress cover to prevent inhaling the dust. The diatomaceous earth (DE), also known as silicon dioxide, that is used as a powder to treat bed bug infestations is NOT the same DE that you use in your pool filter!

One popular product to stop infestations is called Bed Bug Powder. It is a mix of pyrethrum and diatomaceous earth.

DE that is formulated for pest control has been tested with animals and does not seem to be harmful if eaten, but silica gel and boric acid are toxic when ingested. Except in the case of DE, if you have pets or young children who may be tempted to lick or eat the white powder, be careful to apply it only in areas that they can't get to.

Other Bed Bug Related Resources

Early History of Bedbugs In America

Bed Bug Home Page - The Department of Medical Entomology, ICPMR, Westmead Hospital - Australia

Symbio's Non-Toxic Pest Management Index

bugspray.com

also in House & Home--> Pest Control

also see in Gardening --> Garden Bugs & Pests