Corresponding Author: Pascal Delaunay, Pharm D, Service de Parasitologie–Mycologie, Hôpital de l'Archet, Centre Hospitalier Universitaire de Nice, BP 3079, F-06202 Nice Cedex 3, France. E-mail: email@example.com
A dramatic increase of reported bedbug (Cimex lectularius and Cimex hemipterus) infestations has been observed worldwide over the past decade. Bedbug infestations have also been detected across a wide range of travel accommodations, regardless of their comfort and hygiene levels. Travelers are increasingly exposed to the risks of bedbug bites, infestation of personal belongings, and subsequent contamination of newly visited accommodations and their homes.
We searched Medline publications via the PubMed database. National bedbug recommendations, textbooks, newspapers, and Centers for Disease Control websites were also searched manually.
To detect infested sites, avoid or limit bedbug bites, and reduce the risk of contaminating one's belongings and home, bedbug biology and ecology must be understood. A detailed search of their most classic hiding niches is a key to finding adult bedbugs, nymphs, eggs, and feces or traces of blood from crushed bedbugs. Locally, bedbugs move by active displacement to feed (bite) during the night. Bed, mattress, sofa, and/or curtains are the most frequently infested places. If you find bedbugs, change your room or, even better, the hotel. Otherwise, travelers should follow recommendations for avoiding bedbugs and their bites during the night and apply certain simple rules to avoid infesting other sites or their home.
Travelers exposed to bedbugs can minimize the risks of bites and infestation of their belongings, and must also do their civic duty to avoid contributing to the subsequent contamination of other hotels and, finally, home.
Common bedbugs, Cimex lectularius, and tropical bedbugs, Cimex hemipterus, are hematophagous insects found in close proximity to humans and were once commonly encountered in residential dwellings.[1, 2] Improved domestic hygiene, and the widespread availability and use of effective insecticides, particularly DDT after World War II, against household insect pests (eg, cockroaches, mites, ants) contributed to the decline of bedbugs. However, the choice of synthetic pyrethroid-based insecticides over organochloride-based insecticides for household insect-pest control, together with a preference for insect-attracting baits and/or traps, has lessened their efficacy against bedbugs, even though they had probably been highly effective at their introduction and are now plagued by resistance problems. Since the 1990s, a bedbug resurgence has been observed worldwide, with infestations reported in accommodations and transportation modes, including hotels, trains, aircraft and boats, and homes.[3-6]
Thus, travelers are exposed to the risks of bedbug bites, infestation of their belongings and, subsequently, infestation of other hotels and their homes. To help specialists and travelers reduce the risk of exposure to bedbugs, we describe: their biology and their medical impact; how they travel with travelers; basic information needed to detect them in an infested site; suggestions for avoiding or limiting their bites; ways to decontaminate belongings and luggage; and preventive measures for high-traffic tourist areas.
We searched Medline publications via the PubMed database using the search terms “bedbugs OR bed bugs OR Cimex.” National bedbug recommendations ( Australia, United States, Canada), textbooks, newspapers, and Centers for Disease Control websites were also searched manually.
Bedbugs: Their Biology and Medical Impact
Bedbugs belong to the order Hemiptera and the family Cimicidae. The two main species responsible for biting humans are the common bedbug, Cimex lectularius (Linnaeus 1758), and the tropical bed bug, Cimex hemipterus (Fabricius 1803). In this review, bedbug encompasses both species. Adult bedbugs are flattened, oval-shaped, wingless insects 4 to 7 mm long, usually brown to beige in color (Figure 1A), with a characteristic thickening of the thorax (pronotum) (Figure 1B) and distinct mouthparts for blood feeding (Figure 1C). Both sexes are hematophagous but, under favorable environmental conditions (ie, cool temperature, humidity, shelter), bedbugs can survive over a year without a blood meal. Eggs are whitish and measure 1 to 2 mm (Figure 1D). They are often laid in small masses and a female can reportedly lay 50 to 500 eggs during her lifetime but, in the wild, C lectularius lay 100 to 150 eggs and C hemipterus lay 50 eggs. The immature insects go through five successive developmental stages as nymphs, with each successive progression to the next stage requiring a blood meal, before becoming adults (Figure 1E). The nymphal stages (2–4 mm long), often translucent and light in color, can be difficult to see.[8, 10]
Adults and nymphs are generally only active at night and flee daylight or artificial light (bedside lamp or flashlight), which does not facilitate their detection. Their resting places, egg-laying sites, and breeding areas are generally difficult to access because they are usually unnoticeable, hidden in cracks, and creases, eg, grouped in the folds between the mattress and bed frames, bedside furniture and belongings (eg, clock radio, books), picture frames, curtain rods, peeling wallpaper, baseboards, and the carpet–wall junction. Big and elongated blood spots on the sheets are suggestive of bedbugs crushed by the victim. If a single impregnated female bedbug is brought to a new site, it takes several weeks for the life cycle to start again (Figure 2) and numerous offspring to become detectable.[8, 10] During this latency period, those living on the site are usually not yet bothered by their presence.
No evidence supports bedbug involvement in the transmission of any disease-causing pathogens, but, what is more-and-more frequently reported and related daily by experts or pest-management technicians is psychological disorders or various phobias. Knowing or imagining that you can be blood-sucked by an undetectable insect only when you are asleep is nerve-racking for some people. For physicians, experts, and technicians, empathy, listening, and patience are essential. Even anemia in the case of severe infestation[14, 15] has been reported, but their most common impact remains nuisance biting, and associated dermatological and allergic consequences, ranging from simple bites to systemic manifestations.[16-18] The bite itself is generally not painful but the resulting reaction (Figure 3) can cause serious irritation. Sites of predilection are arms, legs, and neck, ie, parts of the body often exposed during the night. The itching generally occurs in the morning and dissipates slightly in the evening. Like many other arthropod bites, bedbugs can cause unexplained urticaria in travelers and be involved in bacterial superinfections, notably after scratching with contaminated hands or nails, but the role of externally contaminated bedbugs in the latter should not be neglected.[19, 20]
Here, our primary objective is to help the traveler and his/her physician prepare for a trip during which bedbugs might be encountered in the present context of their recent resurgence. For more medically oriented information, physicians, experts, and technicians can refer to our recent review.
Short-Distance Displacement of Bedbugs
Locally, bedbugs move by active displacement, which means they are pedestrians on foot! A bedbug looking for a blood meal walks from his living quarters to sleeping or resting potential victims. The release of heat, carbon dioxide, and perhaps human kairomones during hours of darkness are the three main attracting elements. After each blood meal, the bedbug returns to a resting place, either the same one or a new one, to digest the blood, moult, or lay eggs. When the infestation is low, the distance walked is barely several centimeters: from the bottom of the mattress to the top, from the bed frame to the top of the bed, from curtains to the bed, and so on. On the return trip, several rare bedbugs are on reconnaissance for a new hiding place (pyjama seams, suitcases, sleeping bags, etc). When infestation is denser, the territory explored expands to several meters. For extremely severe infestations, several dozen meters can separate “home” and the primary infestation site. On the basis of personal experience, when bites are few, infested areas are usually relatively small, with correspondingly low numbers of pests. Another possible explanation is that short distance displacement occurs by chance/error, so that the longer the infestation has been active, the greater the likelihood that the bedbugs have moved further away. Walls, electric outlets and conduits, and air ducts can be invaded and this takes several weeks. All degrees of infestation have been described: isolated cases, group sites, entire buildings, or even a citywide outbreak. All types of lodgings or contaminated objects have also been observed: private homes or cars, hotels, hospitals, spas, movies, buses, post offices, shops, stock rooms, televisions, radios, motorcycle helmets, and so on
Long-Distance Displacement of Bedbugs
From these locally infested sites, “passive transport” represents the second mode of travel. This time, the host will fortuitously carry the insect to a new location, situated merely several or several thousand kilometers away, during his journey. Primary infestation of a site does not reflect the hygiene level. Any building can fall victim to primary infestation. In contrast, a good hygiene level, associated with good training of well-informed housekeeping personnel, will assure early detection of the first undesirable squatters. Preventive measures can be initiated very rapidly. Three types of habitats are particularly exposed: (1) Very high “turnover” lodging sites, eg, hotels, motels, YMCAs, bed and breakfasts, night trains, cruise ships, hikers' backpacks containing “the entire household” for several weeks in numerous accommodations. Indeed, all places where guests can use their own sleeping bags or linens are highly exposed to bedbug infestations. (2) The traveler is also a very real source of contamination for accommodations, and must maintain civic behavior! First, detect an infestation of one's belongings; second, isolate uncontaminated belongings and place them in sealed plastic bags; third, know how to stay somewhere without vectoring pests: store all your things in the bathtub or another easy-to-clean area; sleep in uncontaminated clothing (or nude or semi-nude) after having taken a shower; and, lastly, face the challenge of informing the accommodation's manager. (3) The rundown lodgings of the underprivileged, who find on the street or buy cheap second-hand clothes or furniture, books, or other objects. In addition, because these individuals do not have the financial means or training to hire a pest-control company, the infestation level is often high.
Other factors aggravate this worldwide dissemination, notably, enhanced international travel, be it for pleasure (tourism) or professional reasons. Several weeks of sea travel for containers is not an obstacle (as the bedbug can survive several months without eating), and long-distance flights have pressurized and heated cargo spaces, where most insects survive. Bedbug resistance to insecticides has also been demonstrated.[23-25] Furthermore, many affected people (tourists or hotel staff) combat this pest ineffectively because its eradication is complex and requires specialized skills.
Knowing Where to Look to Detect an Infested Site
Even if bedbug presence is independent of the hygiene level, housekeeping staff knowledge and desire to destroy bedbugs can be indirectly revealed by the cleanliness of the room and the general simplicity of its design. A search of the most classic resting sites is essential to find adult bedbugs, nymphs, eggs, and feces (black liquid dots, 1–3 mm in diameter) (Figure 1F) that seep into the cloth, leaving a mark resembling a spot of India ink, or traces of blood from crushed bedbugs.
Bedbug Detection on the Road
The traveler's or sleeper's mission is not to control the hotel for pests; it is to not be bitten and to be careful not to contaminate his/her belongings. So, the search for bedbugs should be rapid and effective. When infestations are extremely severe, a sour smell can be detected. In practice, bedbugs can go just about anywhere and everywhere, and even an expert might miss an early infestation. However, know that bedbugs prefer a narrow hiding place and focus the search there.
Above all, examine the bed, under the sheets look at the mattress seams, corners and in the creases between the mattress and its piping (a term from sewing, refers to the tube of material that is formed around the edges of a mattress or a pillow when its covering is sewn, leaving a fold between it and the mattress, an ideal place for a bedbug to hide), under the brand label, aeration openings, and where the handles are attached (Figure 4A and B). Concerning the structural components of the bed, closely inspect the slats in the corners of the base (Figure 4C). These few observations are mostly sufficient.
If you are anxious or suspicious, begin a search like an expert or as must be done at home.
Bedbug Detection at Home
During the search, the traveler should be armed with a flashlight and a magnifying glass. Around the bed, examine paneling or bricks in contact with the bed and headboard if they are present. In addition, the tops of curtains near the bed should be scrutinized (Figure 4D), the television and its stand, the pillow (Figure 4E), the sofa and its cushions, and corners and its back side, especially if the latter is against the wall (Figure 4F). Bedbugs are social insects, their hiding places generally harbor few individuals, with eggs, and especially several tiny black spots (feces). To diagnose a potential infestation, victims can collect dust particles, perhaps containing bedbugs or parts of them. A local expert can make light microscopy observations. Molecular biology techniques can be applied to help analyze specimen origins but they are usually performed only by research laboratories.[26, 27]
Proposed Recommendations to Limit or Avoid Bedbug Bites
Establishing recommendations against bedbug bites is difficult. The following guidelines should be adapted to the trip and the environment. If you find bedbugs, change your room or, even better, the hotel. If you cannot do so, you have to protect yourself and your belongings from infestation. You must have three items: large garbage bags, mosquito repellents, and an insecticide for clothing impregnation. Repellents and insecticides used for clothing are the same products as those recommended to prevent mosquito bites as prophylaxis against malaria.[28, 29] Place your suitcase, whether it is hard or cloth, or your backpack fully inside the garbage bags, close them securely and put them in the shower stall or bathtub, which are always the least contaminated sites, and they can be left illuminated for the duration of your stay. If there is no bathroom, place the closed garbage bags in the middle of the room on a chair or a simple support with no nooks or crannies. Do not leave any clothes near the bed.
Move the bed away from the headboard, bricks, or paneling. Sleep fully covered. Bedbugs bite little or not at all through clothes-protected parts of the body. Apply the mosquito repellent to exposed skin: feet (if you do not have socks), hands, and face. Anti-bedbug closed sheets, such as sleeping bags, are commercially available. In the morning, take a shower to eliminate any potential bedbugs and place your night clothes in a separate sealed garbage bag to isolate them from your other clothing. Insecticide overuse is likely to be more of a public health issue than bedbug exposure and bites. So, do not use insecticides to control bedbugs or else use only with caution.
Methods to Decontaminate Your Luggage
During your trip or upon returning, it is important not to contaminate other sites or your home. Upon arrival, leave the clothes that you are wearing and your luggage in your bathroom or, even better, in the bathtub. Then, take a shower and get organized to start nonchemical, mechanical (the best for the environment and health), then chemical elimination of potential contaminants infiltrating the objects you brought back with you. The newest suitcases made of shiny, hard plastic are much less likely to house bedbugs, because they have difficulty moving on smooth and often electrostatic surfaces. Moreover, this type of suitcase is easy to clean in the bathtub. Textile suitcases with numerous seams can sometimes be complex to decontaminate and provide favorable lodgings for a clandestine, undesirable traveling companion! Freezing or washing them in the washing machine can be a solution.
Nonchemical Bedbug Elimination
Mechanical elimination (without insecticide, eg, vacuuming, brushing, heating, freezing) is strongly recommended, and even essential to diminish and eradicate a maximum number of bedbugs without risk of inducing resistance to insecticides.[9, 23, 31, 32] In the bathtub, wash, with a large volume of water, and brush resistant sites. Wash clothes and, if possible, textile suitcases in the washing machine at ≥55°C or, for items not amenable to washing, take them, sealed in a plastic bag, to be dry-cleaned; inform the professional to clean these items alone in the machine. Open the sack, emptying it only directly into the machine before closing it again and disposing of it. In some countries, dissolvable laundry bags can be placed sealed directly into the professional or personal washing or dry-cleaning machine. Steam clean the nooks and crannies of your suitcases, clothes, etc. This method is highly effective when a good quality steamer is used to rigorously treat the entire garment. For all furniture able to resist a core temperature ≥55°C, this temperature will kill all bedbugs, regardless of their stage. Large volume heating bags have been specifically designed for this method of elimination. Dry brushing or application of a surface cleaner to cloth folds is a complementary action to eradicate difficult-to-detect eggs and nymphs. Freezing, 1 day at −20°C, is generally effective and can be used for delicate clothing.
How to eliminate the contaminated objects must be well thought out and organized so as not to contaminate other sites. Too often, suitcases, clothes, mattresses, and/or furniture are deposited in the street, donated, or sold. This behavior displaces the bedbug invasion to other locations and must be avoided. You must be certain that the material to be discarded is thoroughly sealed in a garbage bag and will be deposited directly at the garbage dump with no risk of being recovered or stored before its total destruction[31, 32] (and the author's opinions based on personal experience).
Chemical Bedbug Elimination
Insecticides must be used as little as possible by nonprofessionals. As Doggett et al. wrote, “The right type of product and the right formulation are critical for achieving a successful eradication.” Unfortunately, the “world” of insecticides is oversized, complex, and varies according to countries. All generalizations run the risk of having some part wrong. Physicians and others must know that pyrethroids are the most common insecticide and two formulations are available: volatile, against flying insects, and sticky, against walking insects, frequently sold as anti-roach insecticide. This latter type of insecticide against bedbugs can only be applied to strategic points (eg, suitcase hinges, edges, surfaces, seams) and should kill the bedbugs, if they are not resistant.[9, 23, 31, 32] However, insecticides remain one of the most important control methods. Resorting to a pest manager is recommended for any other local strategic insecticide use, but seems beyond the traveler's objectives.
No preventive measure is ideal. Henceforth, never being infested by bedbugs resembles “Mission Impossible” for a hotel or any other structure that frequently lodges people. Hotel owners and their customers must know that primary infestation cannot be fully avoided and is independent of the hygiene level. Basic preventive measures include: staff information, cleaning, renovation, and better bedbug detection.[31, 32]
Daily cleaning of the sites (leaving no crannies, paneling, peeling wallpaper) combined with information campaigns for the housekeeping personnel can minimize the risk of infestation by increasing the chance of early discovery of recently arrived bedbugs. Renovation aims eliminate a maximum of hiding and dark places, transform the room into an unfriendly environment for bedbugs in an area designed to facilitate their detection, and perform nonchemical eradication. Mattress covers can prevent mattress infestation and facilitate the fight against bedbugs. Some available methods enhance bedbug detection. Among them is the dog trained to detect bedbugs by sniffing their odor, but success relies on good training for the dog and the dog owner's entomological knowledge.[9, 34] According to the authors, carton, CO2, methane, pheromone, and traps are considered more-or-less efficient.[35, 36] Nontargeted chemical prevention is poorly effective, and initiates, maintains, and accentuates insecticide resistance.
The bedbug population is expanding exponentially worldwide. This hematophagous insect is highly detrimental to humans because of the dermatological manifestations caused by its bites and superinfection. Fortunately, no risk of vectorial transmission of infectious agents has yet been demonstrated. Bedbug biology and traveling modes over long and short distances must be understood to detect infested sites, avoid or limit bedbug bites, prevent a traveler from becoming a vector of contamination, and adequately decontaminate luggage, clothes, and belongings upon returning home.
Mr Arnaud Cannet, entomologist (University Hospital of Nice, France), Dr Véronique Blanc, biologist (Hospital of Antibes–Juan-les-Pins, France), Professor Pierre Marty (Laboratoire de Parasitologie–Mycologie, Centre Hospitalier Universitaire de Nice, and Inserm U895/Université de Nice-Sophia Antipolis, Nice, France), Dr Cameron Webb (Department of Medical Entomology University of Sydney, Australia), and Janet Jacobson for editorial assistance.
This research has been funded by the French Ministry of Health, Projet Hospitalier de Recherche Clinique 2009 (P. D., PHRC 2010 09-API-01). This review is part of a research program entitled “Cimex lectularius or Bedbugs: Vector of Infectious Agents and Pathogenic Role.”
The Infectiopole Sud Scientific Cooperation Foundation provided funds for the camera and microscope.
Declaration of Interests
The author states that he has no conflicts of interest to declare.