Bedbug

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.

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.

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 color 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 bedbug under various microscopes.

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.

While bedbugs have been known to harbor 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 alarm or distress. With some individuals, it may precipitate mild to moderate cases of delusional parasitosis.

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 color. 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 bedbug 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.[9] 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

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 behavior — 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. In many areas, the initial investigation is aided by the use of professionally trained canine detection teams. A properly trained team can detect and pin point a bedbug infestation within minutes.

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 harbor 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 such as those on the edging of a matress or box spring), 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. One may find a group of bugs in the seams, usually surrounded by black fecal matter and sometimes a reddish brown stain.

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.[2] You probably will find a group of bedbugs huddled together surrounded by black stains on your mattress.

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. The flashlight method is best, if you awaken during the night leave your lights off but use your flashlight to inspect your mattress. As bedbugs are not fast movers you will not miss them.

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.

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 frames can be effectively ridded of adult bedbugs and eggs by use of steam or, used with caution, by spraying rubbing alcohol on any visible bugs (Not a permanent treatment). 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.

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 bedbug 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 bedbugs. 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 bedbugs 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 bedbugs have been received. bedbugs 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, bedbugs may migrate back to their original home. Since immature bedbugs 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 bedbugs, nymphs, or eggs that were inadvertently stored. If even one bedbug survives the treatment(s), a reinfestation can occur. Likewise, an individual may have inadvertently carried a bedbug 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.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Bedbug".