Bedbug
2007 Schools Wikipedia Selection. Related subjects: Insects, Reptiles and Fish
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 Cimex lectularius
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Genus Cimex
Genus Leptocimex
Genus Haematosiphon
Genus Oeciacus
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Bedbugs (or bed bugs) are small nocturnal insects of the family Cimicidae that live by hematophagy, feeding on the blood of humans and other warm-blooded hosts.
Biology
Genera and species
The common bedbug ( Cimex lectularius) is the best adapted to human environments. It is found in temperate climates throughout the world and has been known since ancient times.
Other species include Cimex hemipterus, found in tropical regions (including Florida), which also infests poultry and bats, and Leptocimex boueti, found in the tropics of West Africa and South America, which infests bats and humans. Cimex pilosellus and C. pipistrella primarily infest bats, while Haematosiphon inodora, a species of North America, primarily infests poultry.
Oeciacus, while not strictly a bedbug, is a closely related genus primarily affecting birds.
Physical characteristics
Adult bedbugs are reddish brown, flattened, oval, and wingless, with microscopic hairs that give them a banded appearance. A common misconception is that they are not visible to the naked eye, but adults grow to 4 to 5 mm (one-eighth to three-sixteenths of an inch) in length and do not move quickly enough to escape the notice of an attentive observer. Newly hatched nymphs are translucent and lighter in colour and continue to become browner and molt as they reach maturity. When it comes to size, they are often compared to lentils or appleseeds.
A recent paper by Professor Brian J. Ford and Dr Debbie Stokes gives views of a bed bug under various microscopes.
Feeding habits
Bedbugs are generally active only at night, with a peak attack period about an hour before dawn, though given the opportunity, they may attempt to feed at other times of day. Attracted by warmth and the presence of carbon dioxide, the bug pierces the skin of its host with two hollow tubes. With one tube it injects its saliva, which contains anticoagulants and anesthetics, while with the other it withdraws the blood of its host. After feeding for about five minutes, the bug returns to its hiding place. The bites cannot usually be felt until some minutes or hours later, as a dermatological reaction to the injected agents. Although bedbugs can live for up to 18 months without feeding, they typically seek blood every five to ten days.
Bedbugs are often erroneously associated with filth. They are attracted by exhaled carbon dioxide, not by dirt, and they feed on blood, not waste. In short, the cleanliness of their environments has no effect on bedbugs. Their numbers may be reduced temporarily by vacuuming, but will recover and require vacuuming again.
Health effects on humans
While bedbugs have been known to harbour pathogens in their bodies, including plague and hepatitis B, they have not been linked to the transmission of any disease and are not regarded as a medical threat. Some individuals, however, can get skin infections and scars from scratching bites. While bedbugs are not regarded as a vector of transmissible diseases, they may be a significant source of stress, alarm and/or distress. With some individuals, it may precipitate mild to moderate cases of delusional parasitosis.
Reproductive habits
Female bedbugs can lay up to five eggs in a day and 500 during a lifetime. The eggs are visible to the naked eye measuring 1 mm in length (approx. 2 grains of salt) and are a milky-white tone in colour. The eggs hatch in one to two weeks. The hatchlings begin feeding immediately. They pass through five molting stages before they reach maturity. They must feed once during each of these stages. At room temperature, it takes about 5 weeks for a bed bug to pass from hatching, through the stages, to maturity. They become reproductively active only at maturity.
All bedbugs mate via a process termed " traumatic insemination". Instead of inserting their genitalia into the female's reproductive tract as is typical in copulation, males instead pierce females with hypodermic genitalia and ejaculate into the body cavity. This form of mating is thought to have evolved as a way for males to overcome female mating resistance. Traumatic insemination imposes a cost on females in terms of physical damage and increased risk of infection. To reduce these costs females have evolved internal and external "paragenital" structures collectively known as the “spermalege”. Within the True Bugs (Heteroptera) traumatic insemination occurs in the Prostemmatinae (Nabidae) and the Cimicoidea (Anthocoridae, Plokiophilidae, Lyctocoridae, Polyctenidae and Cimicidae), and has recently been discovered in the plant bug genus Coridromius (Miridae).
Remarkably, in the genus Afrocimex both males and females possess functional external paragenitalia, and males have been found with copulatory scars and the ejaculate of other males in their haemolymph. There is a widespread misbelief that males inseminated by other males will in turn pass the sperm of both themselves and their assailants onto females with whom they mate. While it is true that males are known to mate with and inject sperm into other males, there is however no evidence to suggest that this sperm ever fertilizes females inseminated by the victims of such acts.
Infestations
Method of initial infestation
There are several means by which dwellings can become infested with bedbugs. People can often acquire bedbugs at hotels, motels, and bed-and-breakfasts, thanks to increased domestic and international tourism, and bring them back to their homes in their luggage. They also can pick them up by inadvertently bringing infested furniture or used clothing to their household. If someone is in a place that is severely infested, bedbugs may actually crawl onto and be carried by people's clothing, although this is atypical behaviour — except in the case of severe infestations, bedbugs are not usually carried from place to place by people on clothing they are currently wearing. Finally, bedbugs may travel between units in multi-unit dwellings (such as condominiums and apartment buildings), after being originally brought into the building by one of the above routes. This spread between units is dependent in part on the degree of infestation, on the material used to partition units (concrete is a more effective barrier to the spread of the infestation), and whether or not infested items are dragged through common areas while being disposed of, resulting in the shedding of bedbugs and bedbug eggs while being dragged.
Common location of infestations
Bedbugs are very flat, allowing them to hide in tiny crevices. A crack wide enough to fit the edge of a credit card can harbour bedbugs [even in the ceiling]. In the daytime, they tend to stay out of the light, hidden in such places as mattress seams, mattress interiors, bed frames, nearby furniture, carpeting, baseboards, or bedroom clutter. Bedbugs can settle in the open weave of linen; this will often appear as a gray spindle a centimeter long and a thread wide, with a dark speck in the middle. Bedbugs can be found on their own, but more often congregate in groups. They are not social insects, however, and do not build or stay in nests. These groups of bedbugs are very often found in beds, usually either in the seams of a mattress (usually the seams closest to the sleeper), in the boxspring, or within the structure of the bed itself. They can also be found in a wide variety of locations in a home, such as behind baseboards, behind a picture frame, within books (near the bed), in telephones, or radios near the bed, and within the folds of curtains. When not feeding, bedbugs are likely to be found hiding in shaded areas such as the seam along which the floor and wall meet, or under the edge of the carpet. Bedbugs are capable of travelling as far as 100 feet to feed, but usually remain close to the host in bedrooms or on sofas where people may sleep. They feed every five to 10 days. The manner in which infestations spread throughout a home or within an apartment building is not entirely understood and differs from case to case.
It is important to inspect all adjacent rooms for infestation, as bedbugs travel easily and quickly along pipes and boards. In treatment, it is important to consider the insides of walls as potential places for bedbug infestation.
Size of infestations
The numerical size of a bedbug infestation is to some degree variable, as it is a function of the elapsed time from the initial infestation. With regards to the elapsed time from the initial infestation, even a single female bedbug brought into a home has a potential for reproduction, with its resulting offspring then breeding, resulting in a geometric progression of population expansion if control is not undertaken. Sometimes people are not aware of the insects, but do notice the bites. The visible bedbug infestation does not represent the infestation as a whole, as there may be infestations elsewhere in a home, however, the insects do have a tendency to stay close to their hosts (hence the name "bed" bugs).
Detection of infestations
Many misconceptions exist about bedbugs.
It is a common misconception that bedbug infestations can be detected by smell, or by the presence of small red blood stains. The most reliable way of detecting bedbug infestations is through the presence of bedbug feces, which can stain bedding.
Though bedbug bites can occur singly, they often follow a distinctive pattern of a linear group of three bites, sometimes macabrely referred to as "breakfast, lunch and dinner". These patterns of bites are caused when a bedbug is disturbed in feeding by a person moving, and then the bedbug resumes feeding. Bedbug bites also often occur in lines marking the paths of blood vessels running close to the surface of the skin. The effect of these bites on humans varies from person to person, but often cause welts and swelling that are more itchy and longer-lasting than mosquito bites. Some people, however, have little or no reaction to bedbug bites. Those whose bodies do not initially react may subsequently develop symptoms, however, due to an allergic reaction caused by the development of antigen. Bedbugs never crawl under one's skin and markings implying this may be signs of other skin infections or a severe allergic reaction to bedbug bites.
A technique for "catching" (detecting) bedbugs is to have a light source accessible from bed and to turn it on at about an hour before dawn, which is usually the time when bedbugs are most active. A flashlight is recommended instead of room lights, as the act of getting out of bed will cause any bedbugs present to scatter. Bedbugs can also sometimes be viewed during the day.
Some individuals have used glue traps placed in strategic areas around their home (sometimes used in conjunction with heating pads, or balloons filled with exhaled breath, thus offering the carbon dioxide that bedbugs look for) in order to attract and thus detect bedbug infestations. There are also commercial traps like "flea" traps whose effectiveness is really questionable except perhaps as a means of detection, but traps will certainly not work to control an infestation.
Perhaps the easiest method for detection is to place double sided carpet tape in long strips near or around the bed and check the strips after a day or more. This is also useful in detecting insect presence in general.
Veterinarians may mistake bedbugs' leavings on a pet's fur as " flea dirt".
The above having been said, bedbugs are known for being elusive, transient and nocturnal. For many, the only way to detect and identify with certainty an infestation is to contact a pest control professional.
Incidence of infestations
With the widespread use of DDT in the 1940s and '50s, bedbugs all but disappeared from North America in the mid-twentieth century. Infestations remained common in many other parts of the world, however, and in recent years have begun to rebound in North America. Reappearance of bedbugs in the developed world has presented new challenges for pest control, and, without DDT and similarly banned agents, no fully effective treatment is now in use. The industry is only beginning to develop procedures and techniques.
Another reason for their increase is that pest control services more often nowadays use low toxicity gel-based pesticides for control of cockroaches, the most common pest in structures, instead of residual sprays. When residual sprays meant to kill other insects were commonly being used, they resulted in a collateral insecticidal effect on potential bedbug infestations; the gel-based insecticides primarily used nowadays do not have any effect on bedbugs, as they are incapable of feeding on these baits.
The Professional Pest Management Association, a US advocacy group for pest control operators (PCOs) conducted a "proactive bed bug public relations campaign" in 2005 and 2006, resulting in increased media coverage of bedbug stories and an increase in business for PCOs, possibly distorting the scale of the increase in bedbug infestations. .
Living with infestation
If it is necessary to live with bedbugs in the short term, it is possible to create makeshift temporary barriers around a bed. Because bedbugs cannot fly or jump, an elevated bed can be protected by applying double-sided sticky tape (carpet tape) around each leg, or by keeping each leg on a plastic furniture block in a tray of water. Bed frame can be effectively ridded of adult bedbugs and eggs by use of steam. Small steam cleaners are available and are very effective for this local treatment. A suspect mattress can be protected by wrapping it in a painter's disposable plastic dropcloth, neatly sealing shut all the seams with packing tape, and putting it on a protected bed after a final visual inspection. Bedding can be sanitized by a 120 °F (49 °C) laundry dryer. Once sanitized, bedding should not be allowed to drape to the floor. An effective way to quarantine a protected bed is to store sanitized sleeping clothes in the bed during the day, and bathing before entering the bed.
Vermin and pets may complicate a barrier strategy. Bedbugs prefer human hosts, but will resort to other warm-blooded hosts if humans are not available, and some species can live up to eighteen months without feeding at all. A co-infestation of mice can provide an auxiliary food source to keep bedbugs established for longer. Likewise, a house cat or human guest might easily defeat a barrier by sitting on a protected bed. Such considerations should be part of any barrier strategy.
Predators near bed bug infestations
Some bed bug predators may also be found near bed bug infestations. The most common bed bug predator are masked hunters.
Jeffrey Hahn writes:
- Adult masked hunters are dark brown to black and are elongate oval in shape. When full grown, they're about 3/4 inch long. They have a short, stout, 3-segmented beak. Immature masked hunters are similar but smaller and lack developed wings. They are often covered with dust, lint and other debris, giving them a grayish or whitish appearance. Underneath, however, they are dark-colored like adults. Masked hunters do not feed on human blood. However, they are capable of inflicting painful bites as a defensive reaction if they are disturbed or carelessly handled. The bite feels like a bee sting followed by numbness and swelling. Rarely does a masked hunter bite require medical attention. Masked hunters do not transmit any disease.
It is not wise to introduce masked hunters to bed bug infestations in hopes of exterminating the bed bugs.
Treatment
Self-treatment
Some individuals have had success conducting their own exterminations by preparing an insecticide mixture of pyrethrins and fresh-water diatomaceous earth. At least one manufacturer produces a household insecticide D-20 with only .2% naturally derived pyrethrins and 1.0% Piperonyl Butoxide, which magnifies the pyrethrin's effectivenes by 10 times. Natural pyrethrins are more expensive than many alternatives. The function of the pyrethrins is to stimulate the nervous system of the bugs so that the spasms will allow the diatomaceous earth to desiccate, puncture, and kill the bugs through mechanical action. Great care should be taken not to use products with salt-water diatomaceous earth or heat-treated diatomaceous earth (the common industrial forms), which can damage the lungs of any mammal (dogs, cats, or humans) which inhale it (due to its extreme sharp crystalline edges), and has also been known to cause cancer. Fresh-water diatomaceous earth, however, is commonly used to deworm cats, dogs, and humans, and is considered as safe as table salt. What is sold as food-grade diatomite generally contains very low percentages of crystalline silica.
Others have used fruit and vegetable insecticides, comprised of a mixture of pyrethins and canola oil, which are usually safe for humans and most pets (aside from fish).
One person writes: Contrary to popularly disseminated information, extreme heat or extreme cold is usually not effective in eliminating bedbugs. Pest control professionals receive reports of infestations even in the dead of winter, and manufactured environments of extreme heat or cold (such as encasing a mattress in a bag and placing it in direct sunlight, or placing a suspect piece of bedding or clothing in a freezer) usually cannot stay consistently hot or cold enough to sufficiently kill bedbugs, which are not particularly sensitive to temperature extremes.
From a San Francisco tenant advocate: As someone who has suffered from bedbugs myself, and counsels and follows-through on approximately 35 bedbug cases a month, proper exposure to extreme heat and cold is the most effective means of healthfully treating bedbug infestations. While mattresses generally need replacement because of their nearly unpenitrable thickness; sealing belongings in black plastic bags and leaving them in the boiler room or on a hot rooftop for several days is very successful in killing bedbugs and their eggs. Bedbugs, in fact, are very sensitive to extreme temperatures if left 2-3 days. Adding dry ice to bagged goods suffocates living bedbugs, but does not harm eggs.
In addition, since bedbugs normally disperse, treatment of a bed or mattress is insufficient to eradicate an infestation.
Professional treatment
Selection of professionals
Not all exterminators in North America are familiar with extermination techniques for bedbugs. In the past, fumigation with Cyanogas was used for bedbug control. This was very effective, but also very dangerous. This method is no longer used. Fumigation—that is the use of poison gases—is costly, and though this has been tried as a method of control in isolated cases, it is transient. New infestation can be imported shortly after a fumigation has taken place. Fumigation does work, but it may not be practical, and may not be permitted in most jurisidictions. Care must thus be taken when selecting an exterminator, in order to select a professional who knows how to conduct proper bedbug removal. The National Pest Management Association can assist in the location of pest control professionals.
Necessary number of professional treatments
A survey of pest control professionals conducted by a pest control professor at the University of Massachusetts stated that 68% of all bedbug infestations require three or more treatments, 26% require two treatments, and 6% require just one. However, this survey does not seem to have taken into account the size of the infestation, the size of the venue being treated, the extensiveness of that venue's preparation for the treatment (thus enabling or inhibiting coverage of the poisons), the skill of the exterminator, whether popular nesting places have been disposed of, and the cause behind the original infestation. Treatment Exterminators will often apply a "contact kill" spray directly on bedbugs found in the apartment (such as a mixture of cyfluthrin, pyrethrins, and piperonyl butoxide), and then spray lambda-cyhalothrin on baseboards and other favorite hiding places. Lambda-cyhalothrin acts as a "slow kill" barrier which kills bedbugs after they cross it, and is usually microencapsulated, making it safe to pets and humans after it dries. Often, deltamethrin is also injected into larger crevices. The lambda-cyhalothrin and the deltamethrin are at their strongest for the first two weeks following their application, but usually retain effectiveness for up to 60 days.
Successful treatment of a bedbug infestation is often highly dependent on how thorough the pest control professional is. Although the assessment and judgment of the pest control professional should be respected, most treatments cover such areas within homes as closets, curtains, outside and inside furniture crevices (dresser and desk drawers, night tables, etc.), as well as the interior of electrical outlets and behind pictures hangings on walls. If the choice was made to retain bedding, professionals will often either treat or steam-clean bedframes and the undersurface of solid beds. Some higher-end pest control firms also offer to perform the aforementioned vacuuming
Pre-treatment preparation
Proper preparation is a mandatory requirement for control to be effective. Pest control firms should outline this in detail and provide detailed instructions on what to do. This is generally done by the resident; although some firms may offer preparation for an additional charge, this is uncommon. Preparation involves providing access for pest control treatment as well as taking measures to ensure that bedbugs are destroyed or contained. If a home is not properly prepared, successful elimination is practically impossible. Although preparation may be difficult for some people (for example, seniors or handicapped individuals), it is essential for effective treatment, and thus in such cases family members, friends or social or charitable agencies may need to provide assistance.
Packing
All furniture and appliances in the dwelling usually need to be pulled away from the baseboards, and it is commonly asked that all furniture containing potential hiding crevices, such as bookshelves and desks, be emptied and left open for the exterminator to spray. Items in tightly sealed containers are usually safe from bedbug infestation and need not be emptied. Pest Control Operators may declare an item untreatable upon inspection--especially items of wood or paper.
Laundry
Everything that can be laundered should be laundered, and laundered in advance of the treatment, then placed in plastic bags. This would include stuffed animals, drapes and so on.
The items should be securely tied into plastic bags, and emptied directly from the bags into the machines. (The bags should then be immediately disposed of.) It is heat, not water, that kills any bedbugs residing within the laundered items; so the items should be washed in hot water, regardless of normal washing directions, and should be dried with medium heat (preferably high heat) for 20 minutes or more. (For those who have the ability to measure the temperature of the water in their washing machine, or of the hot air in their dryer, the target heat range is 120°F (49°C).)
(If a marathon laundering session such as described is financially prohibitive, it has been posited by some that the items need only be run through the dryer, not the washing machine. However, the extensive water and spinning action associated with washing machines may assist in dislodging bedbugs from where they are residing within clothes and laundered.) However, this is optional as the heat of the cycle of drying will effectively kill all stages—eggs, immature stage (nymphs) and adults.
For items that require dry cleaning, the dry cleaners should be informed that the items in question are potentially infested, and the items should be bagged. (However, many dry cleaners then may refuse to accept the items.)
Steam cleaning of carpets can be helpful; although bedbugs will not be in the middle of the floor, they may be under the carpets at the edges of rooms. Vacuuming is especially important, however. Pesticide is applied at perimeters and is effective, but the more steps are taken to assist removal, the more thorough the elimination will be.
Vacuuming
The mechanical removal of bedbugs by vacuuming is a most important part of preparing for control. Vacuuming alone will not solve the problem, but it will substantially reduce bedbug numbers and thus help reduce the population as part of preparing for treatment. A crevice attachment should be used on the seams of mattresses, on box springs, on bed legs, within furniture interiors, behind pictures, on curtains, and anywhere there is a possibility of the insects hiding (e.g. inside dresser drawers, dresser cases, under chairs, etc.). Carpets should also be vacuumed throughout the home, preferably with a power-head. Baseboards should also be vacuumed using the crevice tool—not swept—prior to the exterminator's arrival. Vacuum bags should then immediately be removed and placed in doubled plastic bags and placed into strong plastic bag for disposal. Spraying inside the vacuum cleaner bag with an aerosol insecticide or 50/50 alcohol/water mix is a good idea. The bags should be stored outside of home before collection. Incineration is not practical in the vast majority of urban centres and may be illegal.
Steam treatment
Some pest control firms do offer steam treatment for items like mattresses or upholstered furniture especially when individuals are concerned about pesticides on bedding. This has only a very limited effectiveness, however, it is quite effective in this range of less than 1/2 inch of penetration. This also depends on the time that the steam is applied to the surface of the item. Small steam cleaners for domestic use can be useful for mattresses and the surfaces of upholstered furniture. This is a worthwhile option if there are issues of allergy, and the homeowner takes the time to treat carefully in this limited context.
Managing bedding
There are differing opinions as to whether it is necessary to dispose of mattress, boxsprings, futons, pillows, and other bedding. There is of course often a heavy cost involved in the complete replacement of such bedding. It is clear, also, that getting rid of infested bedding alone does not solve the problem. The decision to replace bedding or not depends on the condition of and often related level of infestation within the items, the comfort level of the owner, whether the owner can afford replacement, and aesthetics. A reasonable rule of thumb is that new bedding does not need to be replaced but if bedding is older and replacement may have been done soon in any case, then of course, replacing it AFTER control is a welcome clean start. Treatment of bedding items must be done with care and according to the label on the insecticide used. Mattresses typically need local treatment with non-residual insecticides at seams and borders. Boxsprings are more difficult to treat as there are more places for the insects to hide. The notion that getting rid of bedding helps solve the problem is misguided. Infestation must be handled first and then if new bedding is desired, the old bedding can be disposed of. Spread of infestation in apartment buildings is increased by tenants deciding to throw away old bedding. An infested mattress or box spring dragged in a hallway to an elevator will cause bedbugs to fall off or even run off the item, and these may then find their way into other units. As noted here, the use of plastic bags to protect bedding after treatment or to enclose bedbugs when the items are being thrown away are invaluable in preventing spread of infestation. It is also suggested to slash or mark up infested items so that others do not take them back into the building.
After the mattress and/or box spring or futon has been treated, placing these inside a cotton, polyvinyl or polyethylene bag is a good idea as a secondary means of defense. Bedbugs like to hide near the victim and are commonly found on seams of mattresses, or within the structure of box springs. The mattress bag serves to reduce this likelihood and in the case of box springs, it seals any remaining insects inside the bag. The mattress bag also protects the mattress from the mess of staining caused when bedbugs aggregate on seams. The bag is a good idea either until the infestation has been totally eliminated or in the case of good quality cotton bags, useful as a permanent protection for the mattress—and also to enable easier control if infestation recurs.
Those who end up disposing of suspect items should enclose them in plastic mattress bags, or large garbage bags, to prevent shedding bugs and eggs on their way to the disposal site. Care should also be taken to label throwaway items with a warning about the suspected bedbug infestation, as furniture is often reclaimed by dumpster divers.
New items should not be purchased until after the infestation has been thoroughly eliminated. Also, many retailers offer disposal of old mattresses. This can pose obvious problems if new and old mattresses are carried together on the same truck without the proper precautions taken.
Treatment
Exterminators will often apply a "contact kill" spray directly on bedbugs found in the apartment (such as a mixture of cyfluthrin, pyrethrins, and piperonyl butoxide), and then spray lambda-cyhalothrin on baseboards and other favorite hiding places. Lambda-cyhalothrin acts as a "slow kill" barrier which kills bedbugs after they cross it, and is usually microencapsulated, making it safe to pets and humans after it dries. Often, deltamethrin is also injected into larger crevices. The lambda-cyhalothrin and the deltamethrin are at their strongest for the first two weeks following their application, but usually retain effectiveness for up to 60 days.
Gentrol and Phantom can also be used for bed bug control. Gentrol contains the active ingredient (S)-Hydroprene, an insect growth regulator (IGR) that disrupts the normal growth development of cockroaches and stored product pests, drain flies and fruit flies, as well as bed bugs. Phantom® uses an active ingredient known as chlorfenapyr. It is non-repellent and relatively long-lasting.
Successful treatment of a bedbug infestation is often highly dependent on how thorough the pest control professional is. Although the assessment and judgment of the pest control professional should be respected, most treatments cover such areas within homes as closets, curtains, outside and inside furniture crevices (dresser and desk drawers, night tables, etc.), as well as the interior of electrical outlets and behind pictures hangings on walls. If the choice was made to retain bedding, professionals will often either treat or steam-clean bedframes and the undersurface of solid beds. Some higher-end pest control firms also offer to perform the aforementioned vacuuming.
Most infestations are not successfully handled by one treatment alone. Most require exterminators to visit multiple times. In multi-unit dwellings, such as apartment buildings, the whole building should be treated, in order to avoid a situation where bed bugs travel out of the treated unit, only to infest other apartments and/or repeatedly reinfest the original unit.
Post-treatment
Bedbugs can often be seen alive for up to two weeks following treatment of a dwelling, although they should not be seen in great number (e.g., only one or two). It is important to continue to monitor for bedbugs after the initial treatment.
Vacuuming should not be performed for a period of time following treatment, as some pesticides dry as a fine film, and can be prematurely removed from the environment if vacuumed, allowing infestations to survive the treatment.
Anecdotal evidence seems to suggest that many, and perhaps most, people who successfully deal with bedbug infestations find themselves overly paranoid about the possibility of reinfestation for varying lengths of time. These feelings of anxiety may have some relation to delusional parasitosis: "Sometimes an initial and real insect infestation precedes and triggers the delusion [...] Out of desperation the victims may move out of their home, only to report later that the ‘bugs’ have followed them there too." (The Physician’s Guide to Arthropods of Medical Importance, J.A. Goddard, CRC Press, 1993.)
On the other hand, evidence likewise suggests that reinfestations do occur often, especially under certain circumstances. In multi-unit buildings, landlords often choose to save money by exterminating only those apartments where complaints of bed bugs have been received. Bed bugs easily travel from one apartment to the next along pipes and through holes or cracks in the wall, floor, or ceiling. So a thorough and repeated extermination of one apartment may clear the infestation for a time in that unit. Eventually, bed bugs may migrate back to their original home. Since immature bed bugs are as small as the period in a newspaper sentence, is also possible that items stored in sealed containers during the treatment period may contain bed bugs, nymphs, or eggs that were inadvertently stored. If even one bed bug survives the treatment(s), a reinfestation can occur. Likewise, an individual may have inadvertently carried a bed bug or nymph outside the home (in clothing, laptop case, purse), and these may cause infestations at work, in a car, and so on. This can lead to a recurrence at home.