water (at least 60 degrees celsius) or freezing them at −20 °c (−4 °f). most consumer-grade freezers are inadequate to kill bedbugs because they cannot create sufficiently low temperatures. unremovable textiles such as mattresses can be steamed to at least 60 °c (140 °f) and this method can penetrate deep into the textile to effectively kill bed bugs in, potentially, under one minute. heating tents or chambers can be used for infested materials or entire rooms can be heated to at least 55 °c (131 °f) to effectively eradicate infestation. there is no evidence to indicate that a combination of non-chemical methods plus insecticides is more effective than non-chemical methods alone with regards to eradication of bed bug infestations. insecticides are mostly ineffective for the eradication of bedbug infestations as most bedbugs are resistant to insecticides, including pyrethroids which are found in approximately 90% of commercial grade insecticides. furthermore, insect foggers (known as "bug bombs") are ineffective in the eradication of bed bug infestation as they are unable to penetrate bed bug harborages. resistance to pesticides has increased significantly over time, and there are concerns about harm to health from their use. once established, bed bugs are extremely difficult to get rid of, particularly in buildings with multiple dwellings, as they may be present in other parts of the building than the dwelling being treated, and can re-establish populations by moving from infested to decontaminated areas. mechanical approaches, such as vacuuming up the insects and heat-treating or wrapping mattresses, are effective. an hour at a temperature of 45 °c (113 °f) or over, or two hours at less than −17 °c (1 °f) kills them. this may include a domestic clothes drier for fabric or a commercial steamer. bed bugs and their eggs will die on contact when exposed to surface temperatures above 180 °f (82 °c) and a steamer can reach well above 230 °f (110 °c). a study found 100% mortality rates for bed bugs exposed to temperatures greater than 50 °c (122 °f) for more than 2 minutes. the study recommended maintaining temperatures of above 48 °c (118 °f) for more than 20 min to effectively kill all life stages of bed bugs, and because in practice treatment times of 6 to 8 hours are used to account for cracks and indoor clutter. this method is expensive and has caused fires. starving bedbugs is not effective, as they can survive without eating for 100 to 300 days, depending on temperature. it was stated in 2012 that no truly effective insecticides were available. insecticides that have historically been found effective include pyrethroids, dichlorvos, and malathion. resistance to pesticides has increased significantly in recent decades. the carbamate insecticide propoxur is highly toxic to bed bugs, but it has potential toxicity to children exposed to it, and the us environmental protection agency has been reluctant to approve it for indoor use. boric acid, occasionally applied as a safe indoor insecticide, is not effective against bed bugs because they do not groom. distribution main article: epidemiology of bed bugs bed bugs are found everywhere in the world. before the 1950s about 30% of houses in the united states had bedbugs; this percentage has fallen, which is believed to be partly due to the use of ddt to kill cockroaches. the invention of the vacuum cleaner and simplification of furniture design may have also played a role in the decrease. others believe it might simply be the cyclical nature of the organism. however, rates of infestation in developed countries have increased dramatically since the 1980s. this is thought to be due to greater foreign travel, increased immigration from the developing world to the developed world, more frequent exchange of second-hand furnishings among homes, a greater focus on control of other pests, resulting in neglect of bed bug countermeasures, and increasing bedbug resistance to pesticides. the decrease in cockroach populations due to insecticide use may have aided bed bugs' resurgence, since cockroaches eat bedbugs. increasing resistance to ddt and other potent pesticides may have also contributed, as may bans on ddt. the u.s. national pest management association reported a 71% increase in bed bug calls between 2000 and 2005. the number of reported incidents in new york city alone rose from 500 in 2004 to 10,000 in 2009. in 2013 chicago was listed as the us city with most bedbug infestation. in response the chicago city council passed a bed bug control ordinance to limit spread. additionally, bed bugs are reaching places in which they never established before, such as southern south america. the rise in infestations has been hard to track because bed bug infestation is not an easily identifiable problem, and also people do not talk about it. most reports have been collected from pest-control companies, local authorities, and hotel chains, and the problem may be more severe than is currently believed from reports. species the common bed bug (cimex lectularius) is the species best adapted to human environments but is also known from birds, chiroptera, gallus (chickens and relatives), myotis myotis, and sheep (ovis aries). it is found in temperate climates throughout the world. other species include c. hemipterus, found in tropical regions, which also infests poultry (including gallus) and bats, and leptocimex boueti, a relative of c. lectularius adapted for the tropics of west africa and south america, which infests bats and humans. c. pilosellus and c. pipistrella primarily infest bats, while haematosiphon inodora, a species of north america, primarily infests poultry. evolution cimicidae, the ancestor of modern bed bugs, first emerged approximately 115 million years ago, more than 30 million years before bats—their previously presumed initial host—first appeared. from unknown ancestral hosts, a variety of different lineages evolved which specialized in either bats or birds. the common (c. lectularius) and tropical bed bug (c. hemipterus), split 40 million years before homo evolution. humans became hosts to bed bugs through host specialist extension (rather than switching) on three separate occasions. historical reports 1870s–1890s advertisement for a bed bug exterminator. it reads "use getz cockroach and bed bug exterminators, sold by all druggists." 1860 engraving of bed bug parts: a. intestines – b. antenna of the male – c. eye – d. haustellum, or sucker, closed – e. side view of sucker – f. under part of head – g. under lip – gg. hair of the tube, and outside cases – h. egg-bag – i. larva emerging from the eggs bed bugs were first mentioned in ancient greece as early as 400 bc, and later by aristotle. pliny's natural history, first published circa ad 77 in rome, claimed bed bugs had medicinal value in treating ailments such as snake bites and ear infections. belief in the medicinal use of bed bugs persisted until at least the 18th century, when guettard recommended their use in the treatment of hysteria. bed bugs were also mentioned in germany in the 11th century, in france in the 13th century, and in england in 1583, though they remained rare in england until 1670. some in the 18th century believed bed bugs had been brought to london with supplies of wood to rebuild the city after the great fire of london (1666). giovanni antonio scopoli noted their presence in carniola (roughly equivalent to present-day slovenia) in the 18th century. traditional methods of repelling or killing bed bugs include the use of plants, fungi, and insects (or their extracts), such as black pepper; black cohosh (actaea racemosa); pseudarthria hookeri; laggera alata (chinese yángmáo cǎo | 羊毛草); eucalyptus saligna oil; henna (lawsonia inermis or camphire); "infused oil of melolontha vulgaris" (presumably cockchafer); fly agaric (amanita muscaria); tobacco; "heated oil of terebinthina" (i.e. true turpentine); wild mint (mentha arvensis); narrow-leaved pepperwort (lepidium ruderale); myrica spp. (e.g. bayberry); robert geranium (geranium robertianum); bugbane (cimicifuga spp.); "herb and seeds of cannabis"; "opulus" berries (possibly maple or european cranberrybush); masked hunter bugs (reduvius personatus), "and many others". in the mid-19th century, smoke from peat fires was recommended as an indoor domestic fumigant against bed bugs. dusts have been used to ward off insects from grain storage for centuries, including plant ash, lime, dolomite, certain types of soil, and diatomaceous earth or kieselguhr. of these, diatomaceous earth in particular has seen a revival as a non-toxic (when in amorphous form) residual pesticide for bed bug abatement. while diatomaceous earth often performs poorly, silica gel may be effective. basket-work panels were put around beds and shaken out in the morning in the uk and in france in the 19th century. scattering leaves of plants with microscopic hooked hairs around a bed at night, then sweeping them up in the morning and burning them, was a technique reportedly used in southern rhodesia and in the balkans. bean leaves have been used historically to trap bedbugs in houses in eastern europe. the trichomes on the bean leaves capture the insects by impaling the feet (tarsi) of the insects. the leaves are then destroyed. 20th century until the mid-20th century, bed bugs were very common. according to a report by the uk ministry of health, in 1933, all the houses in many areas had some degree of bed bug infestation. the increase in bed bug populations in the early 20th century has been attributed to the advent of electric heating, which allowed bed bugs to thrive year-round instead of only in warm weather. bed bugs were a serious problem at us military bases during world war ii. initially, the problem was solved by fumigation, using zyklon discoids that released hydrogen cyanide gas, a rather dangerous procedure. later, ddt was used to good effect, though bedbugs have since become largely resistant to it. the decline of bed bug populations in the 20th century is often credited to potent pesticides that had not previously been widely available. other contributing factors that are less frequently mentioned in news reports are increased public awareness and slum clearance programs that combined pesticide use with steam disinfection, relocation of slum dwellers to new housing, and in some cases also follow-up inspections for several months after relocated tenants moved into their new housing. society and culture legal action bed bugs are an increasing cause for litigation. courts have, in some cases, exacted large punitive damage judgments on some hotels. many of new york city's upper east side homeowners have been afflicted, but they tend to remain publicly silent in order not to ruin their property values and be seen as suffering a blight typically associated with "lower social class." local law 69 in new york city requires owners of buildings with three or more units to provide their tenants and potential tenants with reports of bedbug history in each unit. they must also prominently post these listings and reports in their building. idiom "good night, sleep tight, don't let the bed bugs bite," is a traditional saying. literature the bedbug (russian: клоп, klop) is a play by vladimir mayakovsky written in 1928–1929 how the bed bug infiltrated our bedrooms and took over the world was written by brooke borel. research bed bug secretions can inhibit the growth of some bacteria and fungi; antibacterial components from the bed bug could be used against human pathogens, and be a source of pharmacologically active molecules as a resource for the discovery of new drugs.