Posted on 03 September 2010 by Chris Hebbern.
The bed bug resurgence
Bed bugs,Cimex lectularius, have been infesting human habitations for thousands of years. About the size of an apple seed, the bugs can hide in electronics, such as radios, in drawers, in and under furniture, behind baseboards, under loose wallpaper, behind paintings and posters, in small cracks and in the curtains. They only eat blood, and they like the taste of ours.
North Americahas seen a resurgence of bed bugs in recent years, notoriously in New York but also in cities throughout Canada, including Toronto andOttawa. Bed bugs dont discriminate by class or status: the Upper East Side has them; hostels, hospitals, and offices have them, and even the Empire State Building has had them. The bed bugs are back, and they bring with them a plague of sleepness nights.
It doesnt take a nights stay in a bed to acquire the bugs. Cinemas in New York have reported infestations. For bed bugs, a cinema is a perfect environment: darkness, soft furniture with lots of hiding places, and a ready supply of blood meals all together in a confined space. Bed bugs have been reported in offices and commercial properties, notably the offices of Time Warner. In New York City, Victorias Secret and Abercrombie & Fitch have had to shut their doors to deal with the problem.
A survey from the National Pest Management Association (NPMA) and the University of Kentucky confirms the resurgence. Prior to 2000, only 25% of U.S. pest management professionals reported an encounter with a bed bug in the past year. Now, 95% have reported bed bugs, a dramatic and sudden increase. Increased international travel, changes in indoor pest control and pesticide resistance are among the possible explanations for why the bed bugs are back.
Bed bugs hitch rides on people and on their belongings, so increased international travel might have played a role. A visit to an infested hostel or hotel room can end in the bugs being picked up on clothing and in luggage, then redeposited on furniture back home.
Pest control products have also changed. After the second world war, DDT, followed by Malathion once resistance to DDT developed, were used to kill bed bugs. It was very successful. The number of infestations remained low even after DDT was banned in the U.S. in 1972, and they stayed at low levels until the mid 1990s. Bed bug populations could have been kept in check in this period because of the use of broad spectrum residual sprays to kill cockroaches, which were phased out in favour of targeted cockroach treatments and traps in the 1990s. This change in spraying patterns might have allowed bed bug populations to grow, but theres a lot of mystery as to why the bed bugs have returned.
For many of us, bed bugs are a long forgotten memory, a success story from the Golden Age of pesticides. But there is a serious downside to this long post war period of bed bug quiescence: the public and professionals alike have lost the vigilance and knowledge necessary to manage bed bug infestations. An outbreak in a single unit in a multi-dwelling building will spread to other units if not managed correctly, and pest control professionals, who may have never dealt with bed bugs before, are having to learn fast. The public have lost the habit of checking for bed bugs, and it can take a long time to recognise bed bug bites for what they are. It is in this environment of ignorance that bed bugs are flourishing.
A history of the war on bed bugs
Our species has been living with bed bugs for centuries; at least since 3,500 B.C., based on a fossil of a bed bug that was unearthed in an Egyptian village. Bed bugs plagued the Egyptians and the Greeks, who recommended hanging a stags foot from the bedstead or placing a bowl of water underneath. It wouldnt have helped.
In the 18th and 19th Centuries, various housekeeping behaviours were advised for keeping down bed bugs. Wax or plaster of Paris was used for filling holes in the bedstead, walls and floors, to prevent the bugs from finding harborage. Spring and fall cleaning traditions helped, by turning out the beds, emptying rooms for thorough washing, and allowing a full and close inspection for bugs of all kinds. The spring clean-out took advantage of the winter cold to have knocked down bed bug numbers. Housekeepers were encouraged to examine the bedstead weekly, to avoid using wallpaper on the walls, as bugs could hide behind it, and to keep an eye on the servants, apt to bring in bed bugs on their boxes and let their own beds go to ruin. Persons returning from traveling were encouraged to check their luggage for bugs before having it put away.
When it came to defeating bed bugs, thoroughness was a virtue. May the Destroyers of Peace be Destroyed by us. Tiffin & Son, Bug Destroyers to Her Majesty, ran the gas lit sign of the Queens own bed bug hunters in the 1860s. Mr. Tiffin offered the following words of wisdom, as pertinent today as back then:
My work is more method: and I may call it a scientific treating of the bugs rather than wholesale murder. We dont care about the thousands, its the last bug we look for, whilst your carpenters and upholsterers leave as many behind them, perhaps, as they manage to catch.(1)
More generally speaking, people had a much greater vigilance toward bed bugs, something we may have no choice but to reacquire. Dr. Riley, PhD and Government Entomologist described the ubiquity of bed bugs in 1889:
I have occasionally met with a favored individual who had never seen a bed bug; but such fortunate people are rare and there are very few housekeepers who have not, by accident perhaps, or through slovenly servants, made the intimate acquaintance of the ubiquitous pest. Its odor and the effects of its bites are universally known, and the word bed buggy has entered our literature as descriptive of a particular class of odors.
Times have changed. There are relatively few people now in North America that have encountered bed bugs, and even fewer that would be able to recognise the smell. Unfortunately that number is on the rise.
The 19th century saw a number of interesting chemical solutions, of which pyrethrum was one of the better ones. It was derived from dried chrysanthemum petals and sold as Persian Powder or Keatings Powder. It is still used today as a household insecticide, but it breaks down quickly, so wouldnt have provided a lasting cure. Other bed bug treatments were rather more alarming. Corrosive sublimate was frequently recommended, as in this recipe from Dr. Riley in an 1889 edition of Good Housekeeping:
One of the best formulas for a substance with which to paint the cracks in a bedstead or the wall is one ounce corrosive sublimate, half pint alcohol and one quarter pint spirits of turpentine.
In case you were wondering, corrosive sublimate, that is, mercuric chloride, is no longer available for home use due to its acute and cumulative toxicity. It might have killed bed bugs, but eventually it might also do away with the occupant of the bed.
These were the days of not just heroic medicine, but also heroic housekeeping. If housekeepers were not mixing up mercuric chloride, they were beating quicksilver with egg whites, brushing kerosene and benzine into cracks or painting the walls with boiling alum water. They werent much of an advance over earlier remedies. In The Compleat Vermin-Killer, published in 1777, the author recommends a quite alarming bed bug treatment: gunpowder. Spread it about the crevices of your bedstead; fire it with a match, and keep the smoke in. Theres no word as to whether the bed was expected to survive.
One reader wrote in to Good Housekeeping in 1888, describing a brimstone bed bug finisher:
I took two pounds of sulphur, put it in an old pan, set the pan in a larger pan, closed all windows tight, put the pan under the bed, dropped a hot coal in the sulphur and closed the door and left the sulphur to do the rest.
In fact this was one of the more common approaches. Sulphur was a popular choice for fumigant, available in the form of sulphur candles or as brimstone. Bed bug treatments in the 1900s utilised fumigation with sulphur dioxide or hydrogen cyanide, and not unsuccessfully at that. When legislation was passed in 1936 allowing local authorities in England to manage bed bugs, this form of fumigation helped reduce infestations by up to 80%. These harsh chemical fumigants soon fell out of favour because of their very high toxicity and the new availability of less toxic pesticides.
The Golden Age of pesticides
While sulphur and hydrogen cyanide fumigation had a lot of success in eradicating bed bugs in the 1930s, it was DDT that really delivered the knock out punch.
The insecticidal properties of DDT were first discovered in 1939, earning the discoverer a Nobel Prize. DDT was immediately put to use in the war effort, and by the end of the 1940s it had been made available to professionals and homeowners alike. It worked quickly and, unlike the fumigants, did not require direct contact with the insects at the time of spraying. The residue of DDT that remained after application would kill insects that came into contact with it, so any bugs that had remained safely hidden during application would eventually succumb. DDT could be applied to beds, baseboards, walls and mattresses, and it prevented re-infestation for a year. It was inexpensive and only one application was needed to do the job.
DDT was a great success story, but it didnt last. DDT had been made available to the public in 1945, but just two years later, reports emerged of resistant bed bug populations at the Pearl Harbor Naval Base. In 1956, eleven years after DDT was put on the market, the National Pest Control Association had begun to recommend Malathion as an alternative to DDT.
Bed bugs and their exterminators have long been engaged in an arms race: the bugs acquire resistance to new chemicals, necessitating the development and introduction of new pesticides. Bug populations are now showing up with resistance to pyrethroids, one of the most popular classes of pesticides currently in use. In 2008, populations of bed bugs in New York City were found to be 264-fold more resistant to a commonly used insecticide, 1% deltapermethrin, than a population collected in Florida. Researchers from the University of Kentucky analysed 110 bed bug populations from across the U.S., and found 88 % had genetic mutations that produce knockdown resistance to pyrethroids. Complicating matters, the knockdown resistance mutation that confers tolerance to pyrethroids also confers resistance to DDT and vice versa, as both chemicals act by targeting sodium channels. Overuse of DDT in the 1940s and 1950s may have predisposed bed bug populations to later develop resistance to pyrethroids.
DDT, bed bugs and science denial
Despite all that we know about insecticide resistance, there are calls to bring back DDT. If DDT hadnt been banned, as some people are now arguing, the bed bugs wouldnt have come back. Its a claim that doesnt stand up to scrutiny.
The Heartland Institute, a free market think tank, has been pushing the revisionist line. Bed bug outbreak hits all 50 states thanks to DDT ban, they claim. And they arent alone. The Competitive Enterprise Institute points out that we once believed that bed bugs were a thing of the past having been brought under controland essentially eradicated in the U.S.due in part to the pesticide DDT. However, now that the highly effective DDT has been banned for more than three decades, bedbugs are making a resurgence absent pesticide effective enough to zap them and thanks to increased global travel.
The Toronto Sun, picking up the theme, laid the blame for bed bugs squarely at the feet of environmentalists:
Thank environmentalists for a growing bed bug plague in Toronto and elsewhere, a senior city health official told the Sun. Developing countries used DDT in the 1940s and 1950s to control the little bugs who drill into their human host sucking blood to breed. They prefer warm beds to lie in wait for often unsuspecting hosts. But bans of the synthetic pesticide and other toxic chemicals that proved harmful to humans, wildlife and plants, resulted in an explosion in developing countries by the mid-1990s.
In response to news that CNN had an outbreak of bed bugs, Newsbusters gleefully wondered how long it will be before the mainstream media pleads for a lifting of the DTT ban. Even commenters on news stories are repeating the refrain for the return of DDT.
If theres a certain familiarity about these arguments, its because we have heard them before. Just substitute bed bugs for mosquitoes and throw in an attack on Rachel Carson.
When Rachel Carson wrote the book Silent Spring, in 1962, DDT was in widespread use, both in agricultural pest control and as a household pesticide. There was very little awareness of the damage it could cause. In Silent Spring, Carson documented the detrimental effects of DDT and other pesticides on ecosystems. Pesticides like DDT were accumulating in the environment and causing clear harm to populations of bald eagles, birds and fish. Her book was a wake up call to the problem of pesticide overuse and the unexpected ecosystem consequences of persistent chemicals.
Carson was vilified by the chemical industry at the time, but she had science on her side. One year after the books release, at the request of President Kennedy, the Presidents Science Advisory Committee investigated her claims and vindicated Carson. Ten years and three PSAC reviews later, and under the Republican President Richard Nixon, DDT was finally banned in the U.S.
The ban was not comprehensive, as it only applied in the U.S., not worldwide. Factories in the U.S. were permitted to continue manufacturing DDT and to sell it overseas. Exemptions were put in place maintaining DDT as an option in disease vector control in the U.S., and DDT continued to be used to control malaria around the world. Unfortunately, it also continued to be utilised intensively in agriculture, and that overuse helped drive the rapid development of resistance.
DDTs Golden Age was short lived. By 1972, the year of the U.S. ban on DDT, nineteen species of malaria-transmitting insects worldwide had developed resistance to the chemical. If DDT had stopped working it was because the insects had evolved.
Even so, it continues to find a role, albeit much reduced, in malaria control. Indoor spraying with DDT can help keep mosquito numbers down, and South Africa has been using it just for that purpose (although with the drawback that it has been found to make bed bugs more active).
So much for history.
Come the present day, where we are told that environmentalists ignored the science when they pushed for a ban on DDT, and, as a consequence, millions died. As Michael Crichton wrote in his 2004 novel State of Fear: DDT was the best agent against mosquitoes, and despite the rhetoric there was nothing anywhere near as good or as safe. Since the ban, two million people a year have died unnecessarily from malaria, mostly children. All together, the ban has caused more than fifty million needless deaths. Banning DDT killed more people than Hitler. Think tanks like the Competitive Enterprise Institute typically of an anti-regulation, anti-environmental bent have picked up on the theme. CEI claimed: In the absence of DDT use, malaria cases skyrocketed. In an all too typical omission, neither Crichton nor CEI saw fit to mention the development of insect resistance to DDT.
And so back to North America, and back to the bed bugs, where we are told once again that DDT is the solution to our problems.
Lets get real. The problem with controlling bed bugs is not that DDT isnt available. If DDT was brought back to fight bed bugs, it wouldnt get the job done because the insects have evolved. Treating bed bugs with DDT is unlikely to result in complete eradication, and it only takes one egg laying female for an outbreak to recur. Unfortunately there is nothing currently available which is as cheap, fast acting, and long lasting as DDT,. This harkening back to the golden age of pesticides helps no one, and the argument is nonsensical anyway: DDT was banned more than three decades ago, a full 25 years after bed bugs began to show resistance to it, whereas the bed bug resurgence is a far more recent phenomenon. We still dont really know why they are back, but it isnt because of a thirty-eight year ban on DDT.
People need real help to deal with bed bugs. They need good, credible advice, not this shaky denial of history and science. We should see these claims for what they are: an opportunistic attempt to make political capital from peoples desperation. There is a human cost to science denial, and it is paid in false hope.
The good news is that there are effective treatments available, pest control companies are becoming more expert at managing the problem, and local authorities are starting to take the issue seriously, such as the city of Toronto with its Bed Bug Project.
What works and what doesnt
One of the more promising options is heat treatment. In a 1916 edition of Farmers Bulletin, a U.S. entomologist recommended firing up the farmhouse furnace in midsummer to get rid of bed bugs. He was on to something: insects have a maximum tolerance for temperature beyond which they can not survive. To take advantage of this, some companies offer a heat treatment for buildings where propane heaters, tubing and fans circulate hot air and increase the indoor temperature high enough to cook the bed bugs. Its an ingenious solution, albeit not cheap; the heat can get to places that a contact insecticide may not reach, and of course pesticide resistance is not an issue.
Dogs can be used to track down bed bugs. That bed buggy smell that was familiar to our grandparents can give away their position to a trained canine. For peace of mind that a treatment has succeeded and the bugs have not returned, a bug sniffing dog could help, although the New York Magazine warns about possible scams: Any schnook with a mutt can train it to bark, then call his cousin Larry to exterminate the bugs that the dog found. That scam is now widely regarded as a growth industry.
Then there are always going to be people that want a natural, non-chemical bed bug option. Apart from baking the bugs at high temperatures, theres not a lot out there that will work. Neem oil, tea tree oil, lavender and cedar based pesticides simply do not have evidence to recommend their use and their manufacturers are not required to provide any. Bug bombs and foggers wont solve the problem, as the bugs will just scatter and hide; diatomaceous earth, a desiccant, might help, but can take weeks to be effective and cant be applied everywhere that bed bugs hide.
Call a professional. Pest control officers have a number of different techniques and tools at their disposal, from taking apart beds to find harborages, applying pesticides with different modes of action to kill the bugs or prevent egg laying, measures like using diatomaceous earth and residual pesticides, and steam treating mattresses and furniture. Professionals have far more to work with than did people a hundred years ago. While the days when a fumigation with DDT could rid a house of bed bugs are long past, that doesnt mean that the bugs cant be beat. They can, but it takes thoroughness and vigilance as well as modern techniques and technology to get it done.
Data on bed bug resistance to insecticides
CDC statement on bed bugs
Bed Bugs: Lessons from the Past
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