Dec 30 2010

The Coming Bedbug Plague

For the last half a century (more than my entire lifetime) industrialized nations have lived a relatively bedbug-free existence. This year, however, bedbugs have started to make a comeback. Reports of bedbug infestations in hotels, theaters, stores, and homes have increased dramatically. Bedbugs, it seems, are not a thing of the past. Rather we have been living in a brief respite from these parasites, which will now resume their former levels of feasting on the blood of sleeping humans.

To me, this story was surprisingly surprising – meaning that I was initially surprised that we had not permanently dealt with the bedbug problem, and then I was curious as to why I was so surprised. Perhaps it is a result of some cognitive bias worth exploring.

But first – the story of bedbugs.

Bedbugs are small parasitic insects in the family Cimicidae, the most common species being Cimex lectularius. They are good at hiding in small spaces near warm-blooded animals, hence their preference for the bedrooms of humans. They can hide in small cracks, in electrical sockets, or between the slats of a bed. They can go up to a year without feeding, and so are very patient. When a warm blooded animal is resting nearby, they crawl out of their hiding space, bite through the skin, and fill themselves with a meal of blood. (They are technically referred to as blood-sucking ectoparasites.)

As pests go, they are not as bad as some, such as lice. They can cause a skin rash, can cause allergy in susceptible individuals, and are psychologically bothersome. Rarely, more serious skin lesions or secondary infections may result and need to be treated.  Psychological effects can be serious and may include insomnia.  Fortunately, they do not transmit any human disease. But no one wants parasites munching on them while they sleep, and the skin lesions they may cause can be annoying.

Why are they coming back? Bedbugs were mostly eradicated in industrialized nations in the 1940s, partly due to direct extermination efforts, but mostly as a side effect of widespread use of DDT and other insecticides. Since the mid 1990s reports of bedbugs have been on the rise. This is partly due to reduced use of DDT, the development of resistance in bedbugs to DDT and other insecticides, and perhaps other factors, such as the increase in international travel. Bedbugs can spread from location to location by hiding in the personal belongings of travelers.

The problem was also exacerbated by the fact that the current generation of doctors, pest controllers, and other professionals have limited or no experience with bedbugs. So signs of bedbugs were not recognized, and extermination suboptimal. This is quickly changing, of course, and 2010 seems to have been the turning point of awareness of the problem.

If you have an infestation, there are things you can do. According to the CDC, treatments include:

* using monitoring devices,
* removing clutter where bed bugs can hide,
* applying heat treatment,
* vacuuming,
* sealing cracks and crevices to remove hiding places,
* using non-chemical pesticides (such as diatomaceous earth) and
* judicious use of effective chemical pesticides

But professional extermination can be expensive, costing several thousand dollars for a single-family home.

Perhaps we will be able to keep bedbugs from returning to pre-1940 levels, through the various mechanisms listed above. But it seems that even in the best-case scenario bedbugs will return as a pest that needs to be dealt-with, rather than being relegated to quaint-sounding good-night wish.

My initial surprise at hearing this story, I think, reflects an inherent progressivist bias in our thinking. We tend to think of human history as making inexorable progress. This bias is reinforced, especially since the industrial revolution, by the fact that science and technology has been relentlessly progressive. The problem is in the default assumption that all change is progressive – whatever current system we have must be better than the old system because newer is better.

Human history, however, is more complex than our default assumptions. Sometimes history is regressive. And sometimes it is cyclical. Not all current trends will extrapolate indefinitely into the future. Today’s fad is not always the wave of the future.

In my mind bedbugs were a problem of pre- or early industrial societies, and were no longer an issue given modern hygiene and pest-control. I associated bedbugs with an earlier age, and it just seemed incongruous that they could return in the 21st century. But the details tell a different story.

We shouldn’t fall prey to assuming that because bedbugs are currently on the rise that they will continue to do so. Perhaps their return will turn out to be only a brief cycle, and then they will fade once again from our collective attention.

This is perhaps an odd example from which to derive a lesson in metacognition, but those are often the most interesting and instructive. So-called metacognition is thinking about thinking – something skeptics do quite a bit. I find that there is something to be learned about the human thought process from almost any topic, which is one of the generic benefits of education in any area. This is why I encourage my daughters to become interested in anything – pick any topic and then delve as deep as you can, so that they can learn about learning itself.

This experience also reflects a good habit to cultivate, and that is questioning your own thought process. When people tell me that they believe in “X”, often my first question is – why do you believe that? This, of course, is also an excellent question to ask yourself.

16 responses so far

16 thoughts on “The Coming Bedbug Plague”

  1. SARA says:

    You nailed my exact feeling on bedbugs. The first time I heard a story, my skeptic voice screamed and I was sure that when I did the research I would find the whole thing to be a big hyperbolic media frenzy similar to shark attacks.

    I was never more disappointed than when I discovered that there was actual basis for the story. Although I still question whether its at the level of media attention, without attention it won’t get controlled, so I don’t lament too much.

  2. CrookedTimber says:

    As someone who travels much of the summer for work this was not welcome news. I now routinely use this advice from Bug_Girl for checking all my hotel rooms.

    There is probably money to be made with dubious extermination promises and preying on peoples fears. If only I didn’t have this damn conscience 🙂

  3. HHC says:

    One way to deal with insect pests is to wash mattresses in the hot summer months. The cleaning process coupled with drying of the mattresses under the intense heat from the sun will kill the eggs and insect population.

  4. daedalus2u says:

    Quite modest heat is a very effective insecticide. Virtually no eukaryote can survive a body temperature of ~ 120 F (~ 50 C). Usually they use ~140 F just to provide a factor of safety. Heat is used for pest control in flour mills all the time. Some of them are specially designed to allow for periodic heating. Virtually all equipment can tolerate temperatures that would be lethal to insects. Humans can enter such places while they are hot, so long as the RH is low enough.

    Sudden freezing is also a good technique. Some insects can survive cold temperatures, but few can survive actual freezing. Usually they survive below freezing temperatures by producing anti-freeze compounds, both ice nucleating inhibitors, osmolytes and protein-protecting hydrophilic sugars (like trehalose). It takes time for them to invoke those protective measures, so sudden freezing (by putting them in a freezer) is usually quite lethal. Let them warm up and freeze them again and the effects are cumulative. Some organisms do nucleate ice in their tissues, but do so in a controlled way such that they can survive it. That takes time to do. If the freezing is too fast, they are not prepared and there is damage. It takes time at normal temperatures to repair that damage, so if they are thawed and refrozen quickly the damage increases each time.

  5. superdave says:

    I wonder if sleeping in a mosquito net would work. It would certainly be annoying but definitely cheap.

    Also, while cleaniless is not really a factor in getting bed bugs (they eat people not garbage), having a tidy house is helpful in removing hiding places for bed bugs and allowing exterminators to reach crevices.

  6. colluvial says:

    As far as solutions go, maybe we could view our homes as ecosystems and stock them with predators. Spiders, house centipedes, maybe even small lizards. It might make for a little bit of drama with squeamish occupants or guests, but at least you won’t lose any blood!

  7. tmac57 says:

    Bedtime at the Novella home: “Daddy,can you tell us a bedbug story? “

  8. BillyJoe7 says:

    Okay I’ll bite…how could a mosquito net possibly help protect against bedbugs?

  9. tmac57 says:

    Adult bedbugs are larger than the openings on a mosquito net,but then I suppose that you would need to wrap yourself completely in it,and then they could still slip into the layers of netting.It might slow them down but it doesn’t sound very practical.

  10. sonic says:

    To be surprised by something unusual happening is not necessarily a sign of bias– although I would agree that the ‘progress’ bias could add to the surprise.
    If you said you were surprised by some very usual situation– now that stinks of bias– no?

  11. BillyJoe7 says:

    I would be surprised if bedbugs could not get through mosquito netting. Maybe you mean pyrethrin impregnated mosquito netting.

    (I was going to google this but my holiday internet connection speed sucks.)

  12. BillyJoe7 says:

    …oops, I meant “could get through” not “could not get through”

  13. superdave says:

    I have no idea if they would actually work, but if they did they would certainly be cheaper than spraying and buying a new mattress.

  14. eean says:

    Sheesh no way would I seal myself up in a net if I knew there were bedbugs in the bed. I’d take daedalus2u’s advice and just burn the house down.

    …or maybe that wasn’t what he said. 😉

  15. mikerattlesnake says:

    Judicious use of pesticides definitely worked for me. And by “judicious” i mean going all “I AM THE LAW YOU BLOOD SUCKING MOTHERF-” and abandoning the room for a few weeks with windows well open.

  16. BillyJoe7 says:

    I am back home and have full internet access again 🙂
    Here’s what I have found:

    How to prevent bedbugs from eating you:

    – vacuum the carpet and mattress
    – place a blockade around the bed posts
    – encase your mattress and pillow for 6-12 months
    – steam your mattress and cushions to 80 degrees
    – hang the sheets and blankets in the sun
    – wash the sheets and blankets at greater than 60 degrees
    – tumble dry the sheets and blankets on hot for 30 minutes
    – place the sheets and blankets in a freezer for 10 hours
    – insecticide powders and directly applied aerosoles

    However, none of these measures are 100% effective. Even employing all measures is not 100% effective. And the bedbugs can re-enter the bedroom form outside sources.

    What about a mosquito net?

    Mosquito netting comes in two sizes: 1.2mm to stop mosquitos, and 0.6mm to stop smaller insects such as midges, sandflies. Since bedbugs are 4-5mm long, the larger 1.2mm size should be adequate. However, the nymphs are only 1mm in length and hence the smaller 0.6mm size would be needed.
    But, of course, nothing is 100% effective, so…

    How about impregnating the net with insecticide?

    There are two problems: Firstly, who wants to sleep under insecticide impregnated mosquito netting for the rest of their lives. And, secondly, the bedbugs are developing resistance to all the available insecticides.

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