A Traveller's Guide to Bed Bugs
Over the last few years I have developed a rather unusual ritual when checking into a hostel or hotel. Upon entering the room I carefully place my belongings at its centre and move to the bed. I lift up the mattress and slowly inspect its edges, making sure no cracks go unsurveyed. Once I've completed the circuit I move to the bedframe, then check behind the headboard, before finally examining any remaining furniture. This can be somewhat alarming to anyone else present, especially if I've just moved into a shared dormitory, but it has become a necessary step to ensure a good night's sleep. My quarry is the bloodsucking bed bug, something that has recently been haunting the dreams of many travellers across the world.
The common bed bug, Cimex lectularius, has a long association with humans, believed to have started back when we were cave dwellers. The bugs fed on bats in the caves but soon developed a taste for human blood. When left caves in search of better real estate, the bugs came too. Until just 70 years ago they were commonplace throughout the Western world. With the introduction of improved housing law and powerful pesticides in the 1940s, numbers quickly plummeted and bed bugs were consigned to folklore. However, at the turn of the Millennium, reports of new infestations began to surface once again.
But what are bed bugs, where are they coming from and what can we do to prevent their spread?
What are bed bugs?
In a recent study only 10% of 358 people recognized an adult bed bug when one was shown to them . They are commonly mistaken as ticks, arachnids, mites or even ladybirds. This underlying lack of public knowledge has been worsened by the spread of misinformation. A blog by Dr Richard Naylor keeps track of the alarming extent of bed bug myths and factual errors: http://e3.group.shef.ac.uk/2010/09/bugs-publicity-and-misinformation.
The most common misconception I encounter is that bedbugs are dust mites, which are microscopic creatures that live in every bed and rarely bother us. In reality, bed bugs are much larger. Adults grow to about the size of an apple pip, are reddish brown in colour and feed on human blood. These stealthy creatures spend the majority of their time hidden away in cracks and crevices around a host's bed. It is only when you are asleep that the bed bug strikes. It crawls out of its hiding place, silently feeds on you, then scurries back out of sight.
Their covert nature is what makes bed bugs both so hard to detect and difficult to get rid of. It is also what has resulted in my somewhat unusual routine when arriving in new accommodation. The best way to identify a bed bug infestation is to look for what they leave behind. Bed bugs shed their skin whilst growing; discarded skins are a good indicator that you may be sharing your bed with unwelcome guests. Another sign to watch out for are little brown spots on sheets: these are stains left from bed bug poo. You may even find their eggs tucked away in the corner of a mattress or hidden in the joints of the headboard.
A more obvious and dreaded sign of a bed bug visit are their bites. Reactions can vary from person to person, ranging from no visible marks to severe itchy blotches. A single bug may bite multiple times in the search for a juicy capillary, and there may be over 10,000 individuals in an infestation. As such it is common to be bitten hundreds of times in a single evening. This can be extremely distressing and is a real threat to a person's physical and psychological well-being.
The return of bed bugs is also having a huge impact on the tourism industry. Places with a high turnover of visitors such as hotels and hostels are particularly at risk. A hotel's reputation can be damaged beyond repair with even the suggestion that they have bed bugs. The cost of infestations to the economy has been valued in the millions .
Hitchhikers and Stowaways
Bed bugs are flightless; under their own steam a trip of even a few metres can be a daunting affair. They do, however, have a nasty habit of hiding in bags, clothes and other portable items that may be found lying around a bedroom. Stowaways can be transported as far as you go and then start new infestations in your next hotel room. Worse, after staying the night at an infested hotel on holiday, you could be in danger in bringing some bugs back with you on the journey home.
Bed bugs have been intercepted in a startling range of items, including crates of dried curry powder, inside musical instruments, in fresh roses as well as more traditional items of baggage . They can even by transported on the human body.
About a year ago I went along with a pest controller to get some samples from an infested property before it was treated. This was the first time I'd gone out into the field and I had only previously seen infestations in pictures. After donning full body protective suits we entered the property.
Within seconds I began to see small shadows crawling out of the walls. Drawn by the new influx of CO2, the bugs had quickly detected us and come out to feed. I'd been told this departure from their usually shy behaviour was because the property's occupant had been away in hospital and had returned to find the bugs emboldened by their hunger. We moved through the property and I soon found individuals climbing the leg of my suit. I was very careful to avoid leaning against any surfaces.
Despite how heavily infested the flat was, we still had to search meticulously to find where some bugs were hiding. Bed bugs tend to live in clustered groups out of sight and we found them behind the curtains, within the bedframe and even had to unscrew the foot of a sofa where a hundred bugs were found lurking.
Despite this nightmarish environment, the most frightening aspect was the realisation that this was someone's home. A person was living here under these horrible conditions. The situation was so bad that the occupant was covered in the insects. You could clearly see them moving around on his clothes. He asked us how long it would take to treat the property and upon hearing it would last around an hour replied: "Right, well I'm going down to the pub."
It then struck me just how easy it is for bedbugs to spread. Within a few seconds of sitting down at the pub, a few bugs sequestered in folds of material could sneak away and set up a new home, waiting for the next unlucky patron to frequent the premises.
Managing the resurgence
After spending 50 years in relative obscurity, the reasons for the sudden return of the bed bugs have remained a mystery. Several theories have been proposed ranging from global warming and the development of insecticide resistance, to increased air travel and immigration .
Using genetic techniques, it is now possible to measure the dispersal dynamics and genetic makeup of bed bug populations. This is important as it allows us to estimate how many bugs start a new infestation, where they came from and the extent of bed bug movement. In order to do this we use genetic fingerprinting. DNA markers, called microsatellites, allow us to see each individual's unique genetic signature. We can then calculate the probability that different bugs are related. By comparing the relatedness of individuals from different infestations we can determine if one infestation originated from another. The amount of genetic variation within a property also gives us an indication of how many individuals started that infestation and whether there had been multiple introductions from different places.
The results of this have both economic and practical consequences. Legal cases have become a major contributor to the economic cost of bed bugs, with multi-million-pound cases becoming increasingly common. But proving the exact origin of an infestation is vital in order to fairly settle these cases. Infestations can also return and it is often not clear whether this is the fault of the pest controller for not fully clearing the property or a separate, new introduction. Genetic techniques can now answer these questions unequivocably. And on the practical side, knowing the origin of infestations allows more targeted control efforts, aiding efficient pest management practice.
One of the most powerful tools to manage the resurgence is public awareness. Knowledge of what bed bugs look like, where they hide and how they are being transported is vital to limit their dispersal. Taking a few quick steps when staying away from home, like checking the mattress and avoiding leaving belongings lying around the bed, can greatly reduce your chances of bringing bugs home with you. However, if you do think you have been affected by bed bugs you should always seek out a pest control professional or the local council. Trying to treat the house yourself is not only ineffective but can be damaging to your health.
I'm leaving for Canada next week and will be staying in several different hostels. As per usual I will begin my visit to each establishment by rummaging around, investigating the furniture, and performing my bed bug checks. Hopefully this will soon become common practice for clued-up travellers and I'll stop attracting strange looks. More importantly, greater public awareness will reduce the chances of these unwanted hitchhikers spreading. Fingers crossed, I won't find any uninvited guests accompanying me on my travels...
 Reinhardt K. Harder A, Holland S, Hooper J and Leake-Lyall C (2008) Who knows the bed bug? Knowledge of adult bed bug appearance increases with people's age in three counties of Great Britain. Journal of Medical Entomology 45(5):956-958
 Reinhardt K and Siva-Jothy MT (2007) Biology of the Bed Bugs (Cimicidae) Annu. Rev. Entomol 52:351-374
 Doggett, SL Geary MJ and Russell RC (2004) The resurgence of bed bugs in Australia: with notes on their ecology and control. Environmental Health 4:30-38
 Boase C (2008) Bed bugs (Hemiptera: Cimicidae): an evidence based analysis of the current situation. Proceedings of the 6th International Conference on Urban Pests 7-14