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Bed Bugs 101


Bed Bugs 101 is your premier online resource for bed bug information.  Bed Bugs 101 was created by Richard Cooper, who is regarded as one of the industry's top experts on bed bugs and co author of the most comprehensive text on bed bugs, Bed Bug Handbook – The Complete Guide to Bed Bugs and Their Control.  Bed Bugs 101 was created as an educational tool to help share our knowledge and important research findings with the public. Our goal is to educate the consumer and to increase public awareness regarding this poorly understood pest.

By selecting a topic above, you can learn about all of the different aspects of bed bugs, their control, and ultimately how to protect yourself and your home from an infestation.  Bed Bugs 101 is available as an Online Resource, but you may also click the "Printer Friendly Version" link to print out the entire document.

History & Resurgence

Bed bugs were a common problem in the United States up through the World War II era.  Around this time, they were virtually eradicated from the US with the wide scale usage of pesticides, such as DDT and Malathion.  During the late 1990's bed bugs began to re-emerge as a pest in the United States, Canada, Australia, the UK, along with a number of other countries.  Their secretive behavior, coupled with a lack of public awareness, has enabled this insect to move very efficiently from one dwelling to another and has facilitated their rapid dispersal throughout the country.

While no one can say for certain what caused the resurgence of bed bugs in the United States, there are a number of factors that have probably influenced the re-emergence of this difficult pest.  There has been a general increase in bed bug activity on a world-wide basis over the past decade.  Due to the increased prevalence of bed bugs world-wide, the frequency of encounters with bed bugs during travel is also likely to have increased resulting in a greater number of introductions into the US than in the past.  Most of the early introductions appear to have been associated with travel as many of the early infestations in the late 1990’s were identified in hotel guest rooms.  

It is also likely that changes in pest management practices coupled with the development of resistance to modern day pesticides has contributed to the successful re-establishment of bed bug populations in the United States.  In the past, hotel guest rooms were typically treated on a regular basis with residual pesticides. As a result, bed bugs introduced during travel were likely to contact pesticide as they left the luggage and traveled to the bed.  During the mid 1990's there was a dramatic shift in pest management practices. Routinely scheduled treatments of baseboards in hotels, motels and apartments were replaced with targeted applications of baits for pests such as ants and cockroaches. With the absence of the residual pesticide applications, bed bugs are able to travel freely and safely from the luggage to the bed, and successfully begin an infestation. It is likely that these factors have played a role in the bed bug's ability to become re-established in the United States.

Now that bed bugs are back, they are spreading throughout the United States at a very rapid rate.  Bed bugs are excellent hitch hikers and once they are introduced into an environment are able to readily spread from infested locations to new locations that were previously un-infested. All one needs to do is to spend a night in a bed bug infested environment and there is a good chance that they will take bugs with them to their next destination.  Some of the more common dispersal mechanisms include overnight stays in bed bug infested quarters, the purchase of infested furniture (rental furniture, used/second hand furniture, reconditioned mattresses etc.), the acquisition of discarded items that are infested, and migration of bed bugs from one infested dwelling to another in multi-occupancy settings (apartments, college housing, medical facilities, senior communities etc.) 

Perhaps the most significant factor that has enabled bed bugs to spread throughout the US at an exponential rate is the lack of public awareness. Many people simply don't believe or realize that bed bugs truly exist. As a result people do not think twice before picking up discarded furniture that is infested with bed bugs and bringing them into their home. Once the bugs are introduced it is not uncommon for infestations to go undetected for several months or more.  One of the reasons that infestations are not detected sooner has to do with the cryptic and secretive habits exhibited by bed bugs. They are mostly active at night, coming out of secretive hiding places to feed on people as they lay fast asleep. Their bite is painless so people are unaware that they have been bitten. Once they have finished taking a blood meal they retreat back to their hiding places where they remain undetected and are not likely to come back out until it is time to feed again (often going several days to a week or more between blood meals). In addition many people must first become sensitized to the bite before developing any bite symptoms while others never react at all.  As a result it is not uncommon for people to have delayed reactions of several weeks or more.  Even when symptoms do occur, they are often confused with poison ivy, scabies, allergic reactions etc.  All of these factors enable bed bugs to become very well established before the occupants of the infested structure identify the infestation.   


Adults are small, brownish insects, just under a 1/4” long and are relatively flat. They are nearly as wide as they are long, and oval in shape. Immature bed bugs (nymphs) resemble the adults, but are much smaller and lighter in color. Newly hatched nymphs are translucent and are no bigger than a pinhead (1 mm). After feeding on a blood meal the immature bed bugs may appear bright red in color. Bed bugs lack wings and therefore they do not fly, but they are capable of moving swiftly on both horizontal and vertical surfaces. The eggs are very small (approximately 1mm), whitish, and very difficult to see on most surfaces without magnification (individual eggs are about the size of a dust speck).

Immature Bed Bugs
(start out 1 mm in length and get larger with each developmental stage)
Adult Bed Bug - 1/4" Bed Bug Eggs

Biology & Behavior

Bed bugs belong to the family of insects known as Cimicidae. All members of this family of insects feed exclusively on blood which they require in order to develop and reproduce. There are a number of closely related species in this family that feed on birds, bats and other animals. However, the species most adapted to living with humans is the common bed bug, Cimex lectularius, which is found world wide. The immature bugs go through five developmental stages before reaching maturity. A blood meal is required between each stage. As the immature bed bugs develop they continue to become larger and darker until reaching adulthood. Under favorable conditions (70-90°F), bed bugs can complete development (from egg to adult) in one and half – two months. Cool temperatures or limited access to a blood meal may extend the developmental period. Adults will typically live for just under a year. The adult females typically deposit up to 5 eggs per day depositing them in a wide variety of locations, both on and away from the bed. An adult female may lay up to 500 eggs during her lifetime.

Bed bugs are nocturnal insects and lead a very cryptic lifestyle. As a result, bed bugs are often present for weeks or even months before a single bug is ever seen by the occupants of an infested structure. They live in cracks and crevices associated with bed frames, head boards, mattresses and box springs. However they also will disperse away from the bed and can live between or beneath floorboards, carpeting, under decorative moldings, in or under furniture, behind picture frames, inside wall voids, etc. There is virtually no crack too small for this insect to occupy. It is from these secluded cracks and crevices that the bugs emerge during the nighttime hours to feed on their sleeping host. The bites are typically painless and often go undetected.

Bed Bugs in Crevice of Furniture Eggs glued to felt pad on back of picture frame Natural crevice in pine slat inside box spring (eggs, adults and nymphs located in crevice)

Bed bugs differ from many other blood feeding pests such as mosquitoes, fleas, etc. in that both adult males and females, as well as all of the immature stages, feed on blood. Once they have fed they return back to their hidden resting places. In the absence of a host, bed bugs can continue to survive for many months without a blood meal. In fact it has been reported that in some cases bed bugs can survive a year or more without feeding.

Disease & Bite Symptoms

Although over 28 disease pathogens have been found in bed bugs, transmission of these pathogens to humans has never been documented and is considered highly unlikely. For this reason, they are not considered a serious disease threat. Their medical significance is mainly limited to the itching and inflammation associated with their bite. Not everyone reacts to bed bug bites in the same fashion. Some people have reactions that are delayed for several days or more while others do not react at all. Reactions to bites can also vary significantly between individuals from a mild itchy welt to a more severe rash like symptom. The most common reactions appear as a raised, reddened welt similar to a mosquito bite. Bites tend to be very itchy and often appear in rows of 3-4 welts or more. There are currently a couple of explanations for why bites often appear in rows. The first explanation is based on the sensitivity of bed bugs to motion. A single bug may withdraw its mouthparts while feeding in response to the slightest disturbance (i.e. person twitches during sleep). After removing their mouthparts, the bug will move a short distance and then begin feeding again, resulting in several bites in a row caused by a single bug. The second explanation involves numerous bugs that are lined up one next to the other (typically along a fold in a bed sheet) all feeding at the same time (similar to cattle at a trough). The important point is that the number of welts does not always correlate with the number of bugs that bit the individual. Thus, just a few bugs can be responsible for many welts in a single evening.

It is also very important to realize that bed bugs cannot be diagnosed by the bite alone. While a medical professional can examine the bites, they can only conclude that the bite symptoms are consistent with those produced by bed bugs. This is not a confirmation however it does provide the grounds for suspecting that bed bugs may be present and that a professional should be called in to perform an inspection for the presence of bed bugs in the structure where the bites occurred.

Bite symptoms vary among different individuals.
It is not uncommon for bites to occur in multiples, often in a row or line.


The thought that bed bugs are the result of poor sanitation and/or poverty is a big misconception. Bed bugs do not discriminate based on one’s social status or the cleanliness of their home. The fact is that cleanliness has nothing to do with getting bed bugs. Bed bug infestations can occur in the most expensive hotels, multi-million dollar estates as well as homeless shelters and everything in between, regardless of the existing sanitary conditions. In order for a bed bug infestation to begin they must be introduced by bringing bugs from an infested environment and introducing them to a previously un-infested one. Some examples include staying in a bed bug infested environment, having a guest visit that brings bugs with them, purchasing an item or accepting delivery of an item that has bugs or eggs on it. As a result, bed bug infestations can affect anyone, anywhere, and are occurring in hotels, apartments, single family homes, upscale commercial office buildings, school classrooms, Laundromats, public transportation and the list goes on and on.

While sanitation may not have anything to do with the onset of an infestation, it can have a tremendous impact on the ability to control or eliminate an infestation. Crowded and cluttered living conditions are one of the more challenging obstacles to overcome in an eradication effort. Bed bugs hide and lay their eggs virtually everywhere. As a result clutter provides an unlimited number of areas where bed bugs can harbor and remain well-protected from control efforts.

Clutter can provide an unlimited number of hiding places for bugs to hide.
Bugs and eggs amongst clutter cannot be readily treated with
conventional pesticides creating a real obstacle to control.

Avoiding Infestations

It is important to remember that in order for a new infestation to become established, bed bugs must first be introduced into the previously un-infested environment. The best way to prevent a bed bug infestation is to avoid the activities that place you at risk for an infestation. Some activities are easier than others to avoid. For example it is much easier to avoid purchasing used items than it is to eliminate travel, having overnight guests, or sending children off to summer camp or college. On the other hand it is much easier to avoid picking items up that have been discarded curbside or purchasing used or second hand bedding or furniture. There is no question that an awareness of bed bug risk factors is the first step in avoiding an infestation.

Early detection of bed bug activity is among the most important ways that you can protect yourself from having an introduction of bed bugs turn into a nightmare that is difficult and costly to eliminate. The use of mattress and box spring encasements is one of the most economical and useful tools that can aid in the early detection of bed bugs. It is very important that the encasements have been specifically designed for bed bugs and have been scientifically tested to demonstrate their effectiveness. The most effective encasement that we have examined is the Bug Lock® encasement. By encasing mattresses, any bed bugs that may be introduced, are restricted to the exterior of the encasements where they can be readily detected through a good visual inspection. In addition, mattress and box spring encasements can also prevent the infestation of the mattress and box spring should bed bugs be introduced.

Mattress encasements can be used proactively to prevent the
mattress & box spring from becoming infested if bed bugs are introduced as well as to
aid in the early detection of bed bugs by restricting their activity to the exterior of the
encasement wherethey can be readily detected and dealt with.

It is also very important to become familiar with the signs the bed bugs leave behind so that you know what to look for when conducting an inspection. First it is important to realize that the only time that you will see red blood stains is if a bed bug is crushed while it still has an undigested blood meal in its body (similar to squashing a mosquito while it is still full of blood). After feeding bed bugs will digest the blood meal and excrete it as a dark liquid that will appear as dark spots. The dark “spotting” of excreted blood can be found on box springs, mattresses, bed sheets, furniture or any other place that bed bugs are active. It is also important to be familiar with the shed skins that bed bugs leave behind as they go from one immature stage to the next (similar to how a snake sheds its skin).

Bed bug engorged with blood. Blood smears/spotting are rarely red stains like this. This only happens if an engorged bug is crushed.
Evidence of bed bug "spotting" is much more commonly seen as dark/black stains or smears from the digested blood that is excreted as a dark liquid Shed skins (exoskeletons) of immature bugs as they develop from one stage to the next.

It is wise to be on the look out for bite symptoms and to conduct inspections in the weeks and months following an event that may have exposed you to bed bugs. For example, for several months upon returning from an overnight trip it is a good idea to periodically inspect (at least once every few weeks) your bed and upholstered furniture. As mentioned above, bed bugs often go undetected for several months until their populations become larger and they eventually emerge in areas where they are more easily detected.

Travel and the purchase of used or second hand furniture and/or bedding are still among the most likely ways to introduce bed bugs. It is far easier to avoid purchasing used items than it is to eliminate travel. However there are many steps that can be taken during travel to minimize the likelihood of staying in a bed bug infested environment or bringing bed bugs home with you. (Also see section titled - Protect Yourself When Traveling )

If at any time you have reason to believe that you are experiencing a problem with bed bugs it is very important that you act swiftly and contact a pest management professional to conduct a thorough inspection and evaluate the situation. Bed bugs are extremely difficult to control especially if they are not caught during the early stages of the infestation.

Early Detection

The detection of bed bugs can be very difficult and bed bugs can easily go undetected during an inspection particularly during the early stages of an infestation when only a few bugs or eggs are present.

Even the most qualified inspector will be challenged when the entire infestation consists of only one or two bed bugs or eggs that are present on a piece of luggage that hitch hiked a ride back to your house after a recent stay at a hotel.

Two eggs along the zipper can be difficult to find (click to enlarge image to see eggs)

Shed skins & eggs on the shoulder of a sofa can be difficult to see (click to enlarge image to see eggs)

Shed skin live nymph and egg on suitcase (click to enlarge )

Insect sticky traps/glue boards are often placed out in an effort to catch bed bugs and while these traps may capture some, they are not reliable monitoring devices since any bugs caught on them were by chance. For this reason, the use of glue board type traps is not recommended as a method for concluding that an area is free of bed bugs. Several devices have been specifically developed for the monitoring and/or detection of bed bugs. Devices that are currently available include bed bug interception devices that are placed under the legs of beds and sofas and traps that use attractants such as  carbon dioxide and/or chemical lures(see also section on Early Detection Devices).

Research has indicated that one of the most effective tools for detecting low level bed bug infestations may be interception devices.  These devices are designed to catch bugs as they travel to and from a bed by trapping them as they naturally more around the environment.  Preliminary indications that the best interception devices on the market can detect 80% or more of low level bed bug infestations within 1-2 weeks of being placed under the legs of beds and couches.

The use of mattress and box spring encasements that have been specifically designed and tested for bed bugs is another tool that can be used to help detect the presence of bed bugs. The reason that encasements are so helpful is because your mattress and box spring have many hiding places for bed bugs that make  inspection time consuming and difficult. Without an encasement, evidence of bed bugs is often buried deep inside your mattress and box spring, and can be almost impossible to find. However by encasing the mattress and box spring the bug’s access is restricted to the smooth exterior of the encasement where signs of bed bugs, such as spotting and shed skins or the bugs themselves, are readily detected during an inspection. However by encasing the mattress and box spring the bug’s access is restricted to the smooth exterior of the encasement where they are much more readily detected during an inspection. An additional benefit is realized as the encasements prevent the subsequent infestation of the mattress and box spring. (See Also - Mattress and Box Spring Encasements)

Inspections to find bugs on mattresses and box springs can be very difficult and time consuming

Inspection of encased beds can be done easily, as bugs are restricted to the exterior of the encasement where they can be quickly spotted and dealt with.

For information on the use of bed bug sniffing dogs as a detection method please refer to the following sections Canine Scent Detection for Bed Bugs or Early Detection Tools and Methods

For a more thorough discussion of methods discussed above please refer to Early Detection Tools and Methods.

Protect Yourself When You Travel

There are many steps that can be taken when traveling to reduce the likelihood of staying in a bed bug infested environment and infesting your home when you return from your travels. Preventive measures begin with the type of luggage you have, how you pack, what you do when you arrive at your destination, as well as the steps you take when you return home. The extent to which you try to prevent an unanticipated encounter with bed bugs is directly related to the level of concern you have and how much you are willing to be inconvenienced.

Due to the extensive nature of this subject, this webpage does not go into the exhaustive detail necessary to cover all of the measures that an individual can take to protect themselves while traveling Bed Bug Central has created a guide titled "TRAVEL bedbugFREE"  that goes into detail regarding how to protect yourself from bed bugs when traveling.

Elimination of Infestations

Can bed bugs ever be eliminated once they infest an environment? The simple answer is yes, it is possible to eliminate a bed bug infestation in most situations particularly if the bed bugs are detected shortly after they have been introduced into the environment and client cooperation is not an issue. The longer bed bugs exist without being detected, the greater their opportunity to disperse within the environment, making it harder to find and eliminate 100% of the population. Another factor which plays a major role in how readily a bed bug infestation can be eliminated is the amount of available harborage for bed bugs to use as a safe haven from control efforts. Crowded and/or cluttered conditions, as well poorly sealed baseboards, chair and/or crown moldings, window frames, door frames, paneled walls, etc. offer an environment with virtually unlimited harborages. There are also situations, where bed bugs are originating from a connected structure (i.e. row homes, condominiums, etc) that is under ownership by another party and is not being treated. In situations such as these, elimination may not be possible until a cooperative effort is achieved.

In many cases two or three services may be all that is necessary to eliminate the problem. However, there are also many cases that require a greater number of visits before the problem is resolved. Finally, there are some infestations where it can be difficult if not impossible to achieve 100% elimination.

Regardless of how severe the infestation or how complex the environment, there is one way that bed bug infestations can be eliminated with absolute certainty. Structural fumigations, while an extreme and costly method, will effectively eliminate bed bugs from an infested environment. Structural fumigations are often confused with fogging applications but are in fact very different. Fogging applications or "bombing", as it is often referred to, typically involves the application of a natural pyrethrin and requires that the area being treated be vacated for one to several hours. The process of structural fumigation on the other hand, typically involves tarping the entire structure, and vacating it for several days while a fumigant gas is released into the tented structure. These types of applications are common in the Southern United states and on the West Coast for the control of drywood termites. Structural fumigations are an extremely expensive approach and may not be practical or even possible in many situations. In many parts of the country, it may be difficult to locate a pest management firm that is licensed in fumigation services. Thus while this technique will guarantee elimination of the existing infestation, in most cases it is not likely to be economically practical or feasible. Structural fumigations may not be available in all parts of the country and may be restricted by regulatory agencies in some states.

To better understand what is involved in a true structural fumigation, the following website details the process for structural fumigation for the control of dry wood termites. This will give you a very good understanding of this type of control measure.


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