See publications of the U.S. Dept. of Agriculture.
Bedbug (Cimex lectularius) magnified 5 ×
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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 4-5 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 nymphs are translucent, lighter in color and continue to become browner as they moult and reach maturity. In size, they are often compared to lentils or appleseeds.
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 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.
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.
At room temperature, it takes only about five weeks for a bedbug to pass from hatching to maturity. They become reproductively active only at maturity.
In most observed cases, bites consist of a raised red bump or flat welt, and are often accompanied by intense itching. The red bump or welts are the result of an allergic reaction to the anesthetic contained in the bedbug's saliva, which is inserted into the blood of its victim. Bedbug bites may appear indistinguishable from mosquito bites, though they tend to last for longer periods. Bites may not become immediately visible, and can take up to 9 days to appear. Bedbug bites tend to not have a red dot in the center such as is characteristic of flea bites. A trait shared with flea bites, however, is tendency towards arrangements of sequential bites. Bites are often aligned three in a row, giving rise to the colloquialism "breakfast, lunch and dinner." This may be caused by the bedbug being disturbed while eating, and relocating half an inch or so farther along the skin before resuming feeding. Alternatively, the arrangement of bites may be caused by the bedbug repeatedly searching for a blood vein. People react very differently to bedbugs, and individual responses vary with factors including skin type, environment, and the species of bug. In some rare cases, allergic reactions to the bites may cause nausea and illness. In a large number of cases, estimated to 50% of all people, there is no visible sign of bites whatsoever, greatly increasing the difficulty of identifying and eradicating infestations.
People commonly respond to bed bug infestations and their bites with anxiety, stress, and insomnia. Individuals may also get skin infections and scars from scratching the bedbug bite locations.
Most patients who 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.
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.
As stated above, the most-cited reason for the dramatic worldwide rise in bedbug cases in recent decades is increased international travel. 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.
Since 1999, infestations have been reported in the United Kingdom, Germany, Spain, Australia, Canada, India, Israel and the United States. Two separate studies in Tuscany, Italy offer further correlation of international travel with a resurgence in bedbug infestations. In case 1, in summer 2003 a seven-year-old boy developed a number of papulae that caused severe itching on his lower legs. His parents suspected insects in the boy’s room, and found several in the folds of his mattress. Two specimens were identified as C. lectularius and the room was treated with an insecticide. The house had never been infested with bedbugs before. However, one month earlier, two family friends had flown from Nepal to stay with the family for ten days. In Case 2, a forty-eight-year-old man travelled by car to Pisa, Italy from Prague, Czech Republic in June 2003 and stayed in a rented house with three friends. After several days, the man noticed several bullous eruptions in linear patterns of three on his upper and lower extremities. The man found several insects in his room that were identified as C. lectularius. The rented house was well kept and had never had a bedbug infestation. However, a group of Germans had rented the house a few weeks before the Czech group arrived.
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 pyrethroids. Many bedbugs have grown resistant to the weaker insecticides. In a study at the University of Kentucky 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. 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.
The number of bedbug infestations has risen significantly since the early 21st century. The National Pest Management Association reported a 71% increase in bedbug calls between 2000 and 2005. The Steritech Group, a pest-management company based in Charlotte, North Carolina, 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 6 in Chicago 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.
There are several means by which dwellings can become infested with bedbugs. 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.
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. In some exceptional cases, the detection of bedbug hiding places can be aided by the use of dogs that have been trained to find the insects by their scent much as dogs are trained to find drugs or explosives. A trained dog and handler can detect and pinpoint 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.
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.
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.
Bedbugs are known for being elusive, transient, and nocturnal, making them difficult to detect. While individuals have the option of contacting a pest control professional to determine if a bedbug infestation exists, there are several do-it-yourself methods that may work equally well.
The presence of bedbugs may be confirmed through identification of the insects collected or by a pattern of bites. Though bites can occur singularly, they often follow a distinctive linear pattern marking the paths of blood vessels running close to the surface of the skin. The common bite pattern of three bites often around the ankle or shin close to each other has garnered the macabre colloquialism "breakfast, lunch & dinner."
A technique for catching bedbugs in the act is to have a light source quickly accessible from your bed and to turn it on at about an hour before dawn, which is usually the time when bedbugs are most active. A flashlight/torch is recommended instead of room lights, as the act of getting out of bed will cause any bedbugs present to scatter before you can catch them. If you awaken during the night, leave your lights off but use your flashlight/torch to inspect your mattress. Bedbugs are fairly fast in their movements, about equal to the speed of ants. They may be slowed down if engorged. When the bedroom light is switched on, it may temporarily startle them allowing time for you to get a dust pan and brush kept next to the bed and sweep the bugs into the pan then immediately sweep them into a cup or mug full of water where the bugs drown quickly. Dispose of the water down the sink or toilet. Disinfect the mattress, skirting boards and so on regularly.
Glue traps placed in strategic areas around the home, sometimes used in conjunction with heating pads or balloons filled with exhaled breath offering a carbon dioxide source, may be used to trap and thus detect bedbugs. This method has varied reports of success. There are also commercial traps like 'flea' traps whose effectiveness is questionable except perhaps as a means of detection. Perhaps the easiest trapping method is to place double-sided carpet tape in long strips near or around the bed and check the strips after a day or more.
Also, bedbug infestation give a very distinct odor .
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 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. It is possible to create makeshift temporary barriers from the insects 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. Barrier strategies nevertheless often have beneficial effects: an elevated bed for example, can be protected by applying double-sided sticky 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 by spraying rubbing alcohol on any visible insects, although this is not a permanent treatment. Small steam cleaners are available and are very effective for local treatment. A suspect mattress can be protected by wrapping it in disposable plastic sheeting, sealing shut all the seams 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.
Food-grade diatomaceous earth (DE) can be sprinked under mattresses, along baseboards and on the edges of bookshelves where bedbugs hide. Food-grade DE, although harmless to mammals, including common house pets and humans, is a virtual death sentence for bedbugs. DE is a drying agent and is actually used in many dry pet foods to keep the kibble dry and fresh.
The DE particles abrade the bedbug, essentially dehydrating it of water and lipids. Neem oil (mentioned below) can be added to the DE (1 cup DE to 20 drops neem oil) in a plastic bag before sprinking it around. Other essential oils that can be added are juniper oil, eucalyptus oil, ylang ylang oil, rosemary oil and tea tree oil. The bedbugs hate the smell of the oils, and for those who don't and pass through, they will eventually be killed by the DE itself. Use 20 drops of each essential oil mentioned for each cup of DE.
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 bedbug 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 will complicate a barrier strategy. Bedbugs prefer human hosts, but will resort to other warm-blooded hosts if humans are not available. Some bedbug 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.
BBC1 aired a television program entitled "The One Show" about the growth of bedbug 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 bedbugs was the only effective control. All items of clothing and upholstery (including curtains) in the affected household had to be deep-frozen for at least 3 days in giant freezers to ensure complete eradication. The exact temperature at which bedbugs must be frozen was not mentioned.
Another method that might be useful in controlling bedbugs 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. Some may find the aroma of neem oil objectionable.
An exterminator may use permethrin insecticide. Permethrin is a neurotoxin and is not known to be harmful to most mammals and humans. However it is highly toxic to house cats and lethal to cold blooded animals (snake, turtle, lizard).
The theory that the surviving bedbug populations were forced to switch hosts to birds is also supported by the research done at Texas A&M and the University of Arkansas. In a recent study, researchers subjected 136 adult bedbugs from 22 sampled populations from nine U.S. states, Australia, and Canada to genetic analysis. Their finding concluded that the bedbug populations were never completely eradicated from the United States as there was no evidence of a genetic bottleneck in either the mitochondrial or nuclear DNA of the bedbugs. Researchers suspect that resistant populations of bedbugs have slowly been propagating in poultry facilities, and have made their way back to human hosts via the poultry workers.
Other research is being conducted at Texas A&M and Virginia Tech to be able to use bedbugs in forensic science. Researchers have been successful at isolating and characterizing human DNA taken from bedbug blood meals. One advantage that bedbugs have over other blood feeders being used in forensics is that they do not remain on the host, and instead remain in close proximity to the crime scene. Therefore bedbugs could potentially provide crucial evidence linking the suspect to the crime scene. Researchers are able to identify what hosts are being fed upon, and are taking further steps to be able to identify the individual by genotyping, and to predict the duration from the time of feeding to recovery of viable DNA.