This is general information about bedbugs. For information on control, treatment and bites, see Control and treatment of bedbugs.

A bedbugW (or bed bug) is a small nocturnal insectW of the family that lives by feeding on the bloodW of humans and other warm-blooded hostsW.

## Biology

The common bedbug (Cimex lectularius) is the best adapted to human environments. It is found in temperateW climates throughout the world and lives off the blood of humans. Other species include Cimex hemipterus, found in tropical regionsW, which also infests poultryW and batsW, and Leptocimex boueti, found in the tropics of West AfricaW and South America, which infests bats and humans. Cimex pilosellusW and Cimex pipistrella primarily infest batsW, while Haematosiphon inodora, a species of North America, primarily infests poultry.

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 4-5 mm (1/8th - 3/16th of an inch) in length and do not move quickly enough to escape the notice of an attentive observer. Newly hatched nymphsW are translucent, lighter in colour and continue to become browner as they moult and reach maturityW. In size, they are often compared to lentilsW or appleseeds.

### Feeding habits

Bedbug are generally active only at dawn, with a peak feeding period about an hour before sunrise. They may attempt to feed at other times, however, given the opportunity, and have been observed to feed at any time of the day. Attracted by warmth and the presence of carbon dioxideW, the bug pierces the skin of its host with two hollow tubes. With one tube it injects its saliva, which contains anticoagulantsW and anestheticsW, while with the other it withdraws the bloodW 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, and the first indication of a bite usually comes from the desire to scratch the bite site. Because of their dislike for sunlight, bedbugs come out at night.

Although bedbugs can live for a year or as much as eighteen months without feeding, they typically seek blood every five to ten days. Bedbugs that go dormant for lack of food often live longer than a year, well-fed specimens typically live six to nine 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. 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 cockroachesW, 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.

===Young===


Female bedbugs can lay up to five eggs in a day and 500 during a lifetime.[verification needed] 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 is possible for a newly hatched egg to take only about five weeks for a bedbug to reach maturity[verification needed].

### Disease transmission

Some sources claim that bedbugs carry disease[1] others that they do not. The truth may be that they are host to organisms that carry disease, but this doesn't usually result in the spread of disease to hosts[2].According to the EPA there are no known cases that indicate that bedbugs can pass disease between humans. [3]

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 shockW in a small percentage of people. It is also possible that sustained feeding by bedbugs may lead to anemiaW. It is also important to watch for and treat any secondary bacterial infection.[verification needed]

## History

Bedbugs were originally brought to the United States by early colonists from Europe - as they are not native, they do not need to be considered an important part of the ecosystem.

Bedbugs were believed to be altogether eradicated 50 years ago in the United States and elsewhere with the widespread use of DDTW.

### Global resurgence

Bedbug cases have been on the rise recently across the world. Prior to the mid-twentieth century, bedbugs were very common. According to a report by the UK Ministry of Health, in 1933 there were many areas where all the houses had some degree of bedbug infestation.[4] Since the mid-1990s, reports of bedbug cases have been rising. Figures from one London borough show reported bedbug infestations doubling each year from 1995 to 2001. The rise in bedbug infestations has been hard to track because bedbugs are not an easily identifiable problem. Most of the reports are collected from pest-control companies, local authorities, and hotel chains.[4] Therefore, the problem may be more severe than is currently believed.[5]

As stated above, the most-cited reason for the dramatic worldwide rise in bedbug cases in recent decades is increased international travel.[6] In 1999, four separate infestations throughout the United Kingdom alerted people to the possibility of an increase in the worldwide bedbug population, facilitated by international travel and trade. However, there is evidence of a previous cycle of bedbug infestations in the United Kingdom. The Institution of Environmental Health Officers maintained statistics for bedbug infestations -- data collected from reports and inspections. In the period 1985-1986, the Institution of Environmental Health Officers reported treating 7,771 infestations in England and Wales, and 6,179 infestations in 1986-1987. There were also reports of infestations in Belfast and in Scotland.[7]

Since 1999, infestations have been reported in the United Kingdom, Germany, Spain, Australia, Canada, India, IsraelW[8] and the United States.

The number of bedbug infestations has risen significantly since the early 21st century. The National Pest Management AssociationW reported a 71% increase in bedbug calls between 2000 and 2005.[9] The Steritech Group, a pest-management company based in CharlotteW, North CarolinaW, claimed that 25% of the 700 hotels they surveyed between 2002 and 2006 needed bedbug treatment. In 2003, a brother and sister staying at a Motel 6W in ChicagoW were awarded \$372,000 in punitive damages after being bitten by bedbugs during their stay. These are only a few of the reported cases since the turn of the 21st century.[10]

Another reason for their increase is that today more pest control services use gel-based pesticide baits for control of cockroaches and ants, the most common pests in structures, instead of residual sprays. When residual sprays were used to kill the more common insect pests, they resulted in the collateral control of bedbug populations. The gel-based insecticides primarily used today to control cockroach and ant populations do not have any effect on bedbugs, as bed bugs are not attracted to baits.

One recent theory about bedbug reappearance in the USA involves potential geographic epicentres. Investigators have found three apparent United States epicentres at poultry facilities in Arkansas, Texas and Delaware. It was determined that workers in these facilities were the main spreaders of these bedbugs, unknowingly carrying them to their places of residence and elsewhere after leaving work.[11] Bedbug populations in the United States have increased by 500 percent in the past few years. The cause of this resurgence is still uncertain, but most believe it is related to increased international travel and the use of new pest-control methods that do not affect bedbugs.[12] In the last few years, the use of baits rather than insecticide sprays is believed to have contributed to the increase.

New York City has been more seriously affected with bedbug infestations since the early 21st century. Bedbugs have found their way into hotels, schools, and even hospital maternity wards. Jeffrey Eisenberg, owner of Pest Away Exterminating on the Upper West Side, claims his company currently receives 125 calls a week, compared to only a few just five years ago. In 2004, New York City had 377 bedbug violations. However, in the five-month span from July to November 2005, 449 violations were reported in the city, an alarming increase in infestations over a short period of time. Exterminators and entomology experts believe this is because so many international travellers visit New York each day.[13]

The National Pest Management Association, a US advocacy group for pest management professionals conducted a "proactive bedbug public relations campaign" in 2005 and 2006, resulting in increased media coverage of bedbug stories and an increase in business for pest controllers, possibly distorting the scale of the increase in bedbug infestations.[14]

### Use of pesticides in the 20th century

Bedbugs had nearly been eradicated by the widespread use of potent insecticides such as DDT. However, many of these strong insecticides have been banned from the United States and replaced with weaker insecticides such as pyrethroidsW. Many bedbugs have grown resistant to the weaker insecticides. In a study at the University of KentuckyW bedbugs were randomly collected from across the United States. These “wild” bedbugs were up to several thousands of times more resistant to pyrethroids than were laboratory bedbugs.[9] Another problem with current insecticide use is that the broad-spectrum insecticide sprays for cockroaches and ants that are no longer used had a collateral impact on bedbug infestations. Recently, a switch has been made to bait insecticides that have proven effective against cockroaches but have allowed bedbugs to escape the indirect treatment.[4]

With the widespread use of DDTW in the 1940s and '50s, bedbugs all but disappeared from North America in the mid-twentieth century.[15] Infestations remained common in many other parts of the world and in recent years have also begun to rebound in North America. Reappearance of bedbugs has presented new challenges for pest control without DDT and similarly banned agents.

## Why infestations occur

There are several means by which dwellings can become infested with bedbugs.

Bedbugs thrive in places with high occupancy, such as hotels. People can often acquire bedbugs at hotels, motels, or bed-and-breakfasts, 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. 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. Bedbugs can also be transmitted via animal vectors including wild birds and household pets.[verification needed]

This spread between sites is dependent in part on the degree of infestation, on the material used to partition units 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.

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 progressionW 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.

### Locations

Bedbugs travel easily and quickly along pipes and boards, and their bodies are very flat, which allows them to hide in tiny crevices. 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 be found on their own, but more often congregate in groups. 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.

## Notes

1. "Bedbugs may be a vector for hepatitis BW and, in endemic areas, for American trypanosomiasis (Chagas diseaseW)." Bedbug Bites on emedicine.com
2. "Bedbugs aren't known to spread disease to humans, although they may be host to the organisms that cause hepatitis B and Chagas' disease." Bedbugs at the Mayo Clinic site. Also, Wikipedia states:

Bedbugs seem to possess 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 pathogensW (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.(Sean Rollo The Bed Bug Resource "Can bed bugs pass diseases?" 2007] Therefore bedbugs are less dangerous than some more common insects such as the fleaW. However, transmission of Chagas diseaseW or hepatitis BW might be possible in appropriate settings.(Robert A Schwartz MD, MPH EMedicine "Bedbug bites" 28 March 2007)

3. "There are no cases that indicate bed bugs pass diseases from one host to another. Lab tests have shown that it is unlikely that the insect is capable of infecting its host." http://web.archive.org/web/20100802044230/http://www.epa.gov:80/pesticides/controlling/bedbugs.html
4. Boase, Clive J, "Bed-bugs - reclaiming our cities" The Pest Management Consultancy, Haverhill, UK, Biologist April 2004, Vol. 51 issue 1, p9-12
5. Mark D. Scarupa and Athena Economides, MD Journal of Allergy and Clinical Immunology "Bedbug bites masquerading as urticaria" Vol. 117, Issue 6, June 2006, p.1508-1509
6. Masetti, Massimo and Bruschi, Fabrizio "Bedbug Infestations recorded in Central Italy" Parasitology International Volume 56, Issue 1, March 2007, p81-83
7. King, F; Dick, I; Evans, P. Bed bugs in Britain. Parasitology Today. Vol. 5, no. 4, pp. 100-102. 1989
8. זהירות, הפשפשים חוזרים!, (hebrew) www.haaretz.co.il, retrieved 05.08.08
9. Voiland, Adam "You May not be Alone" U.S. News & World Report 7/16/2007, Vol. 143, Issue 2, p53-54
10. Initi, John "Sleeping with the Enemy" Maclean's, 1/14/2008, Vol. 121, Issue 1, p54-56
11. James Owen http://news.nationalgeographic.com:80/news/2004/05/0513_040513_bedbugs.html National Geographic “Bloodthirsty Bedbugs Stage Comeback in U.S., Europe” 13 May 2004.
12. Jacobs, Andrew “Just Try to Sleep Tight. The Bedbugs are Back.” New York Times, New York, N.Y. Nov 27, 2005 pg1.1.
13. Bayer
14. Bedbugs are back and so are their bites. - Nov. 29, 2005