Bed bug

Bedbug
Cimex lectularius
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hemiptera
Suborder:	Heteroptera
Family:	Cimicidae Kirkaldy, 1909
Genera & Species
Genus Cimex Cimex lectularius Cimex hemipterus (C. rotundatus) Cimex pilosellus Cimex pipistrella Genus Leptocimex Leptocimex boueti Genus Haematosiphon Haematosiphon inodora Genus Oeciacus Oeciacus hirudinis Oeciacus vicarius

Bedbugs (or bed bugs) are small nocturnal insects of the family Cimicidae that live by hematophagy, that is by feeding on the blood of humans and other warm-blooded hosts.

Biology

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.

Adult bedbugs are a 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. 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, lighter in color and continue to become browner and moult 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.

Bedbug 4 mm length 2.5 mm width (Shown in a film roll plastic container. On the right is the sloughed off skin, which this bedbug just recently wore during its nymph form)

Feeding habits

Bedbugs are generally active only at dawn, with a peak attack period about an hour before dawn, though given the opportunity, they may attempt to feed at other times. 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 a year or as much as 18 months without feeding, they typically seek blood every five to ten days. While bedbugs that go dormant for lack of food often live longer than a year, well-fed specimens typically live four to six months. Low infestations may be difficult to detect, and it is not unusual for the victim not to even realize they have bedbugs early on. Patterns of bites in a row or a cluster are typical as they may be disturbed while feeding. Bites may be found in a variety of places on the body.

Bedbugs may be erroneously associated with filth in the mistaken notion that this attracts them. However, severe infestations are often associated with poor housekeeping and clutter. Bedbugs are attracted by exhaled carbon dioxide and body heat, not by dirt, and they feed on blood, not waste. In short, the cleanliness of their environments has effect on the control of bedbugs but, unlike cockroaches, does not have a direct effect on bedbugs as they feed on their hosts and not on waste. Good housekeeping in association with proper preparation and mechanical removal by vacuuming will certainly assist in control.

Disease transmission

Bed bugs seem to posses all of the necessary prerequisites for being capable of passing diseases from one host to another, but there have been no known cases of bed bugs passing disease from host to host. There are at least twenty-seven known pathogens (some estimates are as high as forty-one) that are capable of living inside a bed bug or on its mouthparts. Extensive testing has been done in laboratory settings that also conclude that bed bugs are unlikely to pass disease from one person to another. Therefore bedbugs are less dangerous than some more common insects such as the flea.

The salivary fluid injected by bed bugs typically causes the skin to become irritated and inflamed, although individuals can differ in their sensitivity. Anaphylactoid reactions produced by the injection of serum and other nonspecific proteins are observed and there is the possibility that the saliva of the bedbugs may cause anaphylactic shock in a small percentage of people. It is also possible that sustained feeding by bedbugs may lead to anemia. It is also important to watch for and treat any secondary bacterial infection. Transmission of trypanosomiasis (Chagas disease) or hepatitis B is possible and might be considered in appropriate settings.

Treatment of Bite

In most observed cases a small, hard, swollen, white welt may develop at the site of each bedbug bite. This may be accompanied by severe itching that lasts for several hours to days. Welts do not have a red spot in the center such as is characteristic of flea bites. Some individuals respond to bed bug infestations with anxiety, stress, and insomnia. Individuals may also get skin infections and scars from scratching the bedbug bites.

Most patients that are placed on systemic corticosteroids to treat the itching and burning often associated with bed bug bites find that the lesions are poorly responsive to this method of treatment. Antihistamines have been found to reduce itching in some cases, but they do not affect the appearance and duration of the lesions. Topical corticosteroids, such as hydrocortisone, have been reported to expediently resolve the lesions and decrease the associated itching.

Young

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. two grains of salt) and are a milky-white tone. 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 five weeks for a bedbug to pass from hatching, through the stages, to maturity. They become reproductively active only at maturity.

Reproduction

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

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Bedbug (shown on writing paper)

There are several means by which dwellings can become infested with bedbugs. People can often acquire bedbugs at hotels, motels, and bed-and-breakfasts, as a result of 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 infested items are dragged through common areas while being disposed of, resulting in the shedding of bedbugs and bedbug eggs while being dragged. In some exceptional cases, the detection of bedbug hiding places can be aided by the use of dogs that have been trained to signal finding the insects by their scent much as dogs are trained to find drugs or explosives. A trained team (dog and handler) can detect and pin point a bedbug infestation within minutes. This is a fairly costly service that is not used in the majority of cases, but can be very useful in difficult cases.

Common location of infestations

Blood-fed Cimex lectularius

Bedbugs are very flat, which allows 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, preferring to remain hidden in such places as mattress seams, mattress interiors, bed frames, nearby furniture, carpeting, baseboards, inner walls, tiny wood holes, 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 mattress 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.

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, and do not 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

Slide of Cimex lectularius

Confirmation of the presence of bedbugs may be through identification of the insects collected. Some individuals use the internet for insect identification, or they may take the sample to a university extension laboratory, or to a professional pest control firm. The insects may be difficult to find, but infestations are typically concentrated on or about bedding or upholstered furniture, and clusters of the insects, their eggs, and immature stages may be found on seams of mattresses, box springs and in folds of upholstered furniture.

The pattern of bites as noted earlier is another means of confirming that the infestation is indeed that of bedbugs. Though bedbug bites can occur singly, they often follow a distinctive pattern of a linear group of three bites, always 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 antibodies. 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. Bedbugs are fairly fast in their movements, however, this can vary depending on how recently they have consumed a blood meal, and if treatment has been performed. Some have described their speed of travel as being about that of ants. Immature stages are quite small. A few seconds staring at a patterned sheet may be needed to notice 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. This method has varied reports of success. It likely depends on extent of infestation, and given the choice of a heating pad and low carbon dioxide, it is not unreasonable to presume that the bedbugs will go for a person preferentially -- they have had a long time to evolve in their abilities to find hosts. There are also commercial traps like "flea" traps whose effectiveness is 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".

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, however, this pest was largely absent as a significant part of pest control services for decades, so the pest control industry is in process of ensuring staff are well-trained.

Controlling infestations

With the widespread use of DDT in the 1940s and '50s, bedbugs all but disappeared from North America in the mid-twentieth century.[2] 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 North America has presented new challenges for pest control without DDT and similarly banned agents. Deltamethrin is an effective pesticide.

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 National Pest Management Association, a US advocacy group for pest management professionals(PMPs) 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. Although bedbugs cannot fly or jump, they have been observed climbing a higher surface in order to then fall to a lower one, such as climbing a wall in order to fall onto a bed. That having been said, barrier strategies nevertheless often have beneficial effects: an elevated bed, for example, 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 rid of adult bedbugs and eggs by use of steam or, used with caution, by spraying rubbing alcohol on any visible bugs (although this is 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 drop cloth, 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.

Alternative treatments that may actually work better and be more comfortable than wrapping bedding in plastic that would cause sweating would be to encase your mattress and box springs in impermeable bed bug bite proof encasements after a treatment for an infestation. There are many products on the market but only some products have been laboratory tested to be bed bug bite proof. Make sure to check to see that the product you are considering is more than an allergy encasement, but is bed bug bite proof.

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.

In a television program on BBC1 entitled "The One Show "about the growth of bed bug infestations in London. In the program a pest control officer claimed that the use of insecticides alone was no longer an effective method to control bed bugs as they had developed a resistance to most if not all insecticides that might be used legally in the UK. He stated that insecticide use in conjunction to freezing bed bugs was the only effective control. All items of clothing and upholstery (including curtains) in the effected household had to be deep-frozen for at least 3 days in giant freezers to ensure complete eradication. The exact temperature at which bed bugs must be frozen was not mentioned.

Another method that might be useful in controlling bed bugs is the use of neem oil. It can be sprayed on carpets, curtains and mattresses. Neem oil is made from the leaves and bark of the neem tree native to India. It has been used safely for thousands of years in India both as a natural, effective insect repellent and it is antibacterial. It has recently received US Food and Drug Administration approval for external use. It is also possible to incorporate neem oil into certain types of mattress. Such mattresses are currently being manufactured by a German company.

Further reading

• Forsyth, Adrian. Die Sexualität in der Natur. Vom Egoismus der Gene und ihren unfeinen Strategien. Munich: Deutscher Taschenbuch Verlag, 1991. ISBN 3-423-11331-6.
• Forsyth, Adrian. A Natural History of Sex: The Ecology and Evolution of Mating Behavior. Richmond Hill, Ontario: Firefly Books, 2001. ISBN 1-55209-481-2.
• Goddard, Jerome A. The Physician’s Guide to Arthropods of Medical Importance (second edition). Boca Raton, Florida: CRC Press, 1993. ISBN 0-8493-5160-X.
• MacQuitty, Miranda, and Lawrence Mound. Megabugs: The Natural History Museum Book of Insects. New York: Random House Children's Books, 1995. ISBN 1-898304-37-8, ISBN 1-85868-045-X.
• Quammen, David. The Flight of the Iguana: A Sidelong View of Science and Nature. New York: Delacorte Press, 1988. ISBN 0-385-29592-8, ISBN 0-385-26327-9, ISBN 0-684-83626-2. Provides detail about Xylocaris maculipennis.
• Smithereen Pest Control (Chicago, Illinois), employees of. Personal interviews. August 2005. (Used for semi-rewrite.)
• Martin Leverkus, Ryan C. Jochim, Susanne Schad et al. Bullous allergic hypersensitivity to bed bug bites mediated by IgE against salivary nitrophorin. J. Invest. Dermatol. (2006) 126, 91-96.

External links

[3] The New York City Department of Health and Mental Hygiene "Vector surveillance and control: Bed bug fact sheet" January 12, 2008

• [4] Business Week "The Cost of Bed Bugs" November 8, 2007, 6:16PM EST
• Questions Answered About Bed Bugs
• [5] Bed Bugs in Hotels
• My Observations on Bedbugs, by Dr. Charles A.R. Campbell (historical interest only)
• Bed Bugs Pest Control Information - National Pesticide Information Center
• KidsHealth.Org: "Hey! A Bedbug Bit Me!"
• eMedicine, July 2006: Bedbug bites, Robert A. Schwartz, MD, MPH, et al.
• BedBug.org -An Entire site dedicated to bed bugs information.
• Bed Bugs 101: Information Everyone Should Know about Bed Bugs By Richard Cooper, Entomologist.

Information from specialized sources

University or colleges

• Harvard University:
  • Harvard University University Operations Services: Bedbug Information
  • Harvard School of Public Health: Bedbugs: Biology and Management
• University of Minnesota Extension Service Entomology Yard & Garden Brief: "Masked Hunters" (natural enemy of the bedbug)
• University of Kentucky EntFacts Information Sheet on bedbugs
• University of Sydney and Westmead Hospital Department of Medical Entomology web-page on bedbugs
• University of Minnesota
• Bed Bug University of Florida Featured Creatures

• Bed bug on National Public Radio
• KYW CBS 3 (Phila.), 18 June 2007: "Bed Bug Beagle (Article and Video)"
• The Trenton Times, 10 May 2007: "Battling bedbugs"

• San Francisco Chronicle, 8 April 2007: "Bedbugs Bounce Back: Outbreaks inall 50 states"
• Fox News, 15 January 2007: "Lawyer Sues London Hotel, Claims Bedbugs Attacked Him, Wife"
• Pest Control Magazine, 1 January 2007: "Are Bed Bug Dogs Up to Snuff?"
• New York Times, 15 October 2006: "Everything You Need to Know About Bedbugs But Were Afraid to Ask"
• Toronto Star. 10 October 2006: "Don't Let the Bedbugs Bite Again."
• New York Post. 26 September 2006: "What's Eating Ralph Lauren?"
• New York Times, 19 September 2006: "Another Reason the City Never Sleeps: More Bedbugs."
• New York Times, 27 November 2005: "Just Try to Sleep Tight. The Bedbugs Are Back."
• New Yorker, 4 April 2005: "Night Visitors"
• Emerging Infectious Diseases, Vol. 11, No. 4, April 2005: Bed Bug Infestations in an Urban Environment, Stephen W. Hwang, Tomislav J. Svoboda, Iain J. De Jong, Karl J. Kabasele, and Evie Gogosis
• New York Times, 2 November 2003 : "Sleep Tight, and Don't Let ... Oh Just Forget About It"
• Dermatology Online Journal, Vol. 5, No. 1, May 1999: Cimex lectularius, Arthur C. Huntley, M.D.
• San Diego Union Tribune, 17 December 2007: Tribal justice not always fair, critics contend (Bedbugs in casinos)