Fifty Years of Absence: What Suppressed Bed Bugs, and What Stopped

1. Introduction: a disappearance worth explaining

One structural pest vanished from an entire hemisphere for half a century and then came back. This journal has written about the resistance, the treatment and the cost, and never about the history.

1.1 Those two sentences are hard to hold together

Resistance arrived almost immediately and the suppression lasted fifty years.²

1.2 What this article argues

That the explanation is a succession of chemistries rather than one, that the succession is the strategy our resistance article called the nonstrategy benchmark, and that the resurgence coincides with its end. Sections 6 to 10 are the case.

2. How complete it was

Because the scale is easy to understate.

The species was a ubiquitous human ectoparasite prior to World War II.² Afterwards, infestations were considered uncommon and of minimal health concern, and by the 1990s, few pest controllers had ever encountered one.²

2.1 A career without seeing one

One popular account puts it that a young pest-control worker in London or Chicago could go an entire career without seeing one, and that entomologists openly wondered whether the species was on its way to becoming a rarity in developed countries.⁵

2.2 That is a remarkable outcome

An obligate human parasite, associated with people since antiquity, reduced to a curiosity across the developed world within about a decade.

Nothing else in this journal has been controlled that thoroughly, and our articles on cockroaches, rodents and stored product pests all describe populations that have never been.

2.3 And the reduction was not uniform

One source states that significant reservoirs of bed bug infestation persisted through this period, particularly in inner-city areas, with infestations during the 1950s mainly found in homeless shelters, and prisons, and gives a 1967 to 1973 breakdown of about 61 per cent domestic residential and 25 per cent institutional.⁸

That source is a partisan wiki whose general reliability is contested, we could not corroborate those figures anywhere else, and we report them only because §19's hypothesis depends on whether reservoirs existed. Section 28 repeats the warning.

3. The standard account

As everybody tells it.

Following the introduction of DDT for indoor pest control, bed bug populations declined dramatically across industrialized nations.²

And then resistance brought them back: one account traces the global comeback largely to the insects evolving resistance to the very insecticides that once wiped them out.⁵

3.1 Both halves are true

The decline followed DDT and the resurgent populations are resistant.

3.2 The problem is the middle

Which §4 is about.

4. And the hole in it

If resistance explains the return, the timing needs to work.

Resistance was reported shortly after widespread application.² The resurgence began in the late 1990s.¹

4.1 Roughly fifty years apart

A causal account in which resistance to a compound produces a resurgence half a century later needs to explain the interval.

4.2 And the interval is the interesting part

Because something was suppressing these populations during it, and that something was not the absence of resistance.

That framing is ours.

5. Nineteen forty-eight

The date, and what it means.

The 2026 paper cites work from 1948 and 1958 for DDT-resistant bed bug populations.²

5.1 Within a few years of deployment

DDT came into wide civilian indoor use after the war, so resistance in this species was documented almost as soon as the pressure was applied.²

5.2 Which is the pattern our resistance articles describe

A large population under strong uniform selection, indoors, with no untreated refuge, producing survivors quickly. Our article on reversion argued that structural pest control has every condition that makes resistance fast and reversion slow, and this is the historical instance.

5.3 So the species was never actually beaten chemically

It was beaten operationally, and §6 is how.

6. What actually held them down

The sentence that answers §4.

Emerging populations were likely suppressed by periodic introductions of new broad-spectrum insecticides throughout the mid-to-late twentieth century.²

6.1 Periodic introductions of new compounds

Not one chemistry maintaining control, but a series of them, each arriving in time to handle what survived the last.²

6.2 Which explains the resistance paradox directly

A population resistant to DDT in 1950 met something else in 1955. Resistance to one compound is worth nothing against a compound with a different target, which is the point our cross-resistance articles make in the other direction.

So the species kept solving the previous problem and kept being given a new one, for decades.

6.3 Note the hedge

Likely suppressed. The authors are stating a reconstruction rather than a demonstrated mechanism, and we report it as they do.²

7. Which is a sequence

In the precise sense our resistance management article defined.

A sequence is the solo use of one insecticide until control failure, then the solo use of another.

7.1 That is exactly what happened

DDT until resistance, then the next broad-spectrum compound, then the next, across decades.²

7.2 Nobody designed it

It was the emergent result of a chemical industry producing new actives and a pest control trade adopting whatever worked. The strategy is visible in retrospect rather than in intent.

That observation is ours.

8. And this journal has a name for that

An unflattering one, from the modelling literature.

Our article on resistance management strategy recorded that the modelling calls a sequence the nonstrategy benchmark, the thing every real strategy is supposed to beat, and that rotations and mosaics tended to show minimal gains over it.

8.1 Here it produced the most complete control in this journal

Fifty years of near-absence of a major human ectoparasite across the developed world.²

8.2 Which is not a refutation of the modelling

Those models compare strategies holding the set of available chemistries fixed. This sequence worked because the set kept growing.

8.3 And it reframes what the models are for

Rotation, mixture and mosaic exist to stretch a fixed set of chemistries. They are conservation strategies for a resource, and they matter precisely when the resource stops being replenished.

Which is the situation this trade has been in since the period §10 describes, and it is why the modelling literature became worth reading.

8.4 So the real variable was the pipeline

A sequence with an unlimited supply of new compounds beats everything. A sequence with a fixed supply is the benchmark. The difference is not the strategy but the resource it consumes.

That is our argument and we have not seen it made.

9. Why it worked here

Two further conditions, which we offer as ours.

The target is a specialist. An obligate blood feeder on humans, living in buildings, with no outdoor reservoir in a temperate climate. There is nowhere for a population to sit out a control campaign.

And it was hit incidentally. Broad-spectrum residual treatment applied for everything else reached it too, which is §16.

9.1 And a third: they cannot fly

A wingless obligate parasite disperses by being carried. Every founding event depends on human transport of an object, which is a bottleneck no flying or fast-walking pest has.

Which means interrupting transport-mediated founding events, as §17 describes, is an available intervention for this species and not for most others.

9.2 The first condition is why bed bugs and not cockroaches

German cockroaches went through the same chemical era and were never eliminated, and our articles on them describe populations persisting in voids, drains and neighbouring units throughout. The difference is where the animals can be when the treatment happens.

10. And what ended it

The supply, in one sentence from the review.

With a growing number of insecticides (DDT, carbamates, organophosphates etc.) being no longer available as a result of regulatory restrictions, the mainstay chemistry used for bed bug control over the past few decades has been the pyrethroid insecticides.¹

10.1 From a succession to one class

Which is the end of the mechanism in §6, and it is stated by the review as a matter of regulatory restriction rather than of scientific failure.¹

10.2 A version of this appears elsewhere

One patent specification frames it as the hypothesis that older, more persistent, and now banned pesticides that were at one time effective against bed bugs have been removed from the market in favor of pesticides that are less environmentally persistent but that are also less effective.⁷

And an account of a recent European episode cites a persistent organic pollutants treaty as one of the causes, as the banning of powerful pesticides led to a proliferation of this parasite.⁶

10.3 We are reporting these, not endorsing them

Both are advocacy for a position about regulation. Our article on that treaty examined the comparable claim in a different context and found the attribution considerably more complicated than the headline version.

11. The return

The scale of it, measured.

A survey by a national association and a university, with respondents from 43 countries, found of 521 responding U.S. pest management companies, 95% reported encountering a bedbug infestation in the past year, with Canada (98%), Europe (92%), and Africa/Middle East (90%).⁴

Against before 2000 only 25% of U.S. survey respondents reporting them.⁴

11.1 The survey measures encounters, not prevalence

A firm reporting one infestation in a year counts the same as a firm reporting a thousand.⁴

11.2 Which still carries the finding

Because a rise from a quarter to nearly all firms encountering the species at least once is a change in whether the animal is present in the working environment at all, which is the historical question.

11.3 And the before-2000 figure is not zero

A quarter of firms had encountered one, which is consistent with §2.3's reservoirs rather than with total absence.⁴

11.4 And Canada is the highest figure

Ninety-eight per cent.⁴

12. The synchrony

The detail that constrains every explanation.

The upsurge appears to have started almost synchronously in the late 1990s in Europe, the U.S.A. and Australia.¹

12.1 Almost synchronously is the authors' phrase

Which allows for a few years either way rather than asserting a single date.¹

12.2 Three continents at once

Which is a strong constraint, because any proposed cause has to have been operating in all three at about the same time.¹

13. Which is itself evidence

Our reasoning about what the synchrony admits and excludes.

It fits a shared regulatory change. Restrictions on the same compound classes proceeded in parallel across developed countries on broadly similar timetables.

It fits a shared change in practice. The shift to targeted baiting happened across the same countries for the same commercial reasons.

It fits increased travel. Which rose everywhere at once.

13.1 What it fits less well

A single-origin reintroduction spreading outward, which would be expected to reach three continents sequentially rather than simultaneously.

That inference is ours and §20 reports genetic evidence bearing on it.

14. Eleven factors

The review's list, quoted in full because its length is the point.

Overcrowding in cities, poor construction and the design of modern housing, more clutter and belongings in homes, an increase in the number of houses that are centrally heated, denial/lack of incident reporting by hotels and landlords, increasing trade in second-hand furniture, a greater reliance on communal laundries, unregulated sale, donation, importation and smuggling of second-hand clothing, changes in control practices for other pests that coincidentally controlled bed bug populations, a worldwide increase in secondary hosts including rodents, poultry, dogs and cats and a general decline in public awareness are all factors that have probably contributed to the resurgence.¹

14.1 With resistance named separately

The same review states that several factors have led to this situation, with resistance to applied insecticides making a significant contribution.¹

15. Which is not an explanation

Said carefully, because the review is a serious paper.

A list of eleven contributing factors, each described as having probably contributed, is an accurate statement of the state of knowledge and it does not tell you which one mattered.¹

15.1 The factors are not comparable in kind

Central heating is a physical condition. Second-hand furniture trade is an introduction route. Declining public awareness is a detection effect. They would require entirely different evidence to establish.

15.2 And several are unfalsifiable as stated

More clutter and belongings in homes is not a quantity anybody has measured across the relevant period, in any of the three continents.

15.3 And two of them are about detection rather than population

Denial or lack of incident reporting by hotels and landlords, and a general decline in public awareness.¹

Both would change how many infestations are recorded without changing how many exist, and our articles on what a count measures argue that the two are routinely conflated. A resurgence measured by firms encountering the species is partly a measure of whether anybody is looking.

15.4 Which is not a criticism of the authors

Listing candidate factors honestly is better than asserting one. Our complaint is about how such a list gets used downstream, where any individual item can be quoted as the cause.

16. The practice hypothesis

The one item on the list with a specific mechanism.

That control practices for other pests coincidentally controlled bed bug populations, with cockroaches and ants now routinely being controlled with baits rather than sprays.¹

16.1 Coincidentally is the load-bearing word

Nobody applying a baseboard spray for cockroaches was thinking about bed bugs, which is why the effect was invisible until it was removed.¹

17. Its mechanism is unusually specific

And geometric, which is what makes it interesting.

A trade source sets it out: in the past, hotel guest rooms were typically treated on a regular basis with residual pesticides. As a result, bed bugs introduced during travel were likely to contact pesticide as they left the luggage and traveled to the bed.³

And then: with the absence of the residual pesticide applications, bed bugs are able to travel freely and safely from the luggage to the bed, and successfully begin an infestation.³

17.1 The claim is about a path

Not about killing a population but about interrupting a specific journey, made by a small number of founding individuals, across a treated floor.

17.2 Which is why it could matter so much

Our articles on introduction describe founding events as the bottleneck: a handful of individuals establishing or failing to. A residual deposit across the route that every founder must cross is acting at exactly the point where a population is most vulnerable.

That reading is ours.

17.3 And it explains the specialist point in §9

A cockroach entering a treated kitchen has somewhere else to go. A bed bug arriving in a hotel room has one destination and one route to it.

18. And the chronology fits

Which is the strongest thing about it.

The trade source dates the shift to the mid 1990's, when routinely scheduled treatments of baseboards in hotels, motels and apartments were replaced with targeted applications of baits.³

18.1 The resurgence begins in the late 1990s

A few years later, which is about the interval a founding population needs to become noticeable.¹

18.2 The contested wiki gives a longer chronology

Placing the introduction of a cockroach bait active in the early 1980s and the switch from spraying and baseboard treatment to baits and growth regulators in the early 1990s.⁸

We repeat the reliability warning from §2.3 and note that it is broadly consistent with the trade source on timing.

18.3 But a coincidence in timing is not a demonstration

Several of the eleven factors were also changing in the 1990s, and our articles on attribution argue that a mechanism which is possible is routinely treated as an explanation that applies.

19. The cryptic refugia hypothesis

The newest and least familiar proposal.

An alternative, largely unexplored hypothesis is that contemporary infestations might represent expansions from cryptic refugial populations that persisted through the insecticide era rather than from recent reintroductions from distant sources.²

Under it, small populations would have survived in areas where insecticide exposure or efficient pest control was limited, with low-income rural housing and poultry farms given as examples, maintaining the genetic legacies of historical colonization.²

19.1 Which is a claim about where they were, not why they returned

The two questions are separable and usually conflated. A population expanding from a local refuge and one arriving in luggage from abroad can both be triggered by the same change in conditions.

That distinction is ours.

19.2 And §2.3 is the relevant evidence

Reservoirs in shelters, prisons and inner-city housing, if the figures there are sound, are exactly the refugia the hypothesis requires.⁸

20. What the genetics found

The test, which somebody has run.

The 2026 paper's title reports admixture without recurrent intercontinental gene flow and contrasting patterns of genetic diversity and knockdown resistance profiles reveal independent evolution in resurgent common bed bug populations.²

20.1 Independent evolution

Meaning the resurgent populations on different continents are not recent descendants of a common resurgent source. They developed separately.²

20.2 Contrasting patterns of genetic diversity

Which is what independent histories produce. Populations descended from a single recent source would share a narrow diversity profile; populations with separate histories would not.²

That reading of the phrase is ours and the abstract does not spell it out.

20.3 Without recurrent intercontinental gene flow

Which is a direct statement about the travel hypothesis: whatever role travel plays in moving individuals between buildings, it is not maintaining a genetic connection between continents.²

21. Which bears on the travel account

The explanation the public hears most often.

Increased international travel is cited everywhere, including in an account of a recent European episode where globalization and more frequent international travel is also frequently cited as a cause.⁶

21.1 The genetic finding does not eliminate it

Travel plainly moves bed bugs, and every practitioner has seen it. What the finding constrains is the stronger claim that the resurgence consists of reintroduction from distant sources.²

21.2 And it fits the synchrony better

Three continents developing populations independently and simultaneously points at a change operating in all three, rather than at spread from one.

Which is §13 arriving at the same place from a different direction, and that convergence is ours.

22. And a tension in our sources

Worth flagging because it matters.

A popular science account states that genome studies show the resurgent bugs carry sodium-channel mutations inherited from the rare survivors of the original spraying campaigns.⁵

22.1 That is close to the refugia hypothesis

Descent from survivors of the original campaigns is persistence, not reintroduction.⁵

22.2 And it is stated more confidently than the paper states it

The peer-reviewed source describes the refugia scenario as largely unexplored.²

We give more weight to the journal than to the popular account and flag the discrepancy rather than resolving it.

23. Where this leaves the question

Our assessment, offered as such.

The disappearance is explained. A succession of broad-spectrum chemistries, applied residually and indoors, against a specialist with nowhere to hide.²

The resurgence is not. Eleven candidate factors, one strong mechanistic proposal, a genetic finding that constrains one of the alternatives, and no study apportioning them.

23.1 And the question is answerable in principle

Unlike most of the historical questions in this journal. The genetics establishes where populations came from, application records would establish what changed in practice, and regulatory dates are a matter of public record.

What is missing is somebody assembling the three, which is a smaller gap than the subject's reputation suggests.

23.2 The two best-supported strands point the same way

The narrowing chemistry pipeline and the shift away from residual application.¹³ Both describe the removal of a continuous low-level pressure that nobody was applying on purpose.

23.3 Which is the shape of the answer if there is one

Not that a new thing started, but that an old thing stopped.

That is our reading and it is what we would want tested.

24. What follows for practice

Three things.

The historical control was incidental. Which means nobody has ever deliberately solved this problem, and the current difficulty is not a decline from a period of competence.

The species is resistant by inheritance. Our article on layered resistance describes what the populations now carry, and §5 explains how long they have been carrying it.

And the chemistry pipeline is the variable to watch. Section 8.4 argues the fifty-year success was a function of new compounds arriving, and our article on a pro-insecticide described one of the few genuinely novel modes of action in current use.

24.1 Which is an argument for the non-chemical methods

Heat, encasement, vacuuming, inspection and structural modification are all indifferent to resistance, and our articles on thermal treatment and on monitoring describe them.

If the fifty-year success depended on a chemical resource that is no longer being replenished, then the methods that do not depend on it are the ones whose value rises, and that inference is ours.

25. And the uncomfortable implication

Which we state because the argument leads there.

If the suppression depended on continuous residual broad-spectrum application to buildings people sleep in, then it depended on a practice that was abandoned for reasons unrelated to bed bugs.

25.1 We are not arguing for its return

The reasons for the change include occupant exposure, non-target effects and resistance management, and our articles on all three describe them as sound.

25.2 And the same shape appears in our regulation article

Where a restriction was repealed on the claim that the permitted alternatives did not work well enough. Whatever the merits there, the structure is the same: a measure justified on one set of effects has effects outside that set, and they surface later.

25.3 The point is about what was traded

A control benefit nobody was counting was lost alongside the costs that were being counted, which is a general feature of withdrawing a broad intervention and is visible only afterwards.

That observation is ours.

26. Our own position

The disclosure.

Bed bug work is a substantial part of this trade's revenue here, and an article explaining that the problem exists because of a historical accident is an article explaining why our work is necessary.

26.1 So the incentive runs toward this conclusion

Which a reader should weigh. What we would say against ourselves is that §23 concludes the resurgence is unexplained, and a self-serving article would have picked a cause.

27. The Manitoba position

The most locally relevant subject in the journal after the regulation article.

Canada returned the highest figure in the survey at 98 per cent.⁴ Our articles on bed bug treatment cost and on multi-unit housing describe what that means in this city.

27.1 And the housing stock is the mechanism

Multi-unit buildings with shared walls, services and laundry are where our cockroach and sanitation articles locate the movement between units, and the same structure applies here.

Which means the eleven-factor list's housing items are not incidental to this city. Overcrowding, construction, communal laundries and second-hand furniture trade are all local conditions.¹

27.2 And the cold does not help

Our overwintering articles establish that a heated building is a stable year-round environment, and this is an obligate indoor parasite. The climate that limits so many pests here has no purchase on this one.

27.3 What we could not find

Any Manitoba prevalence figure across the resurgence period, any provincial historical record of when the species returned here, and any local work on which of the eleven factors applied.

28. Limitations and open questions

The two research sources were read as abstracts. The 2012 review and the 2026 genetics paper both reach us through published abstracts and opening sections.¹²

One source is a partisan wiki of contested reliability. Section 2.3 and §18.2 use it for chronology and distribution figures we could not corroborate, and a reader should discount those passages accordingly.⁸

Two sources are patents and one is a trade site. Each arguing for a position, flagged individually.⁷³

We did not read the 1948 and 1958 resistance papers. They reach us as citations inside the 2026 paper's introduction.²

The survey figures measure encounters. Section 11.1.⁴

And the genetics is one study. Published recently, not yet replicated so far as we know, and its conclusions about independent evolution would be the thing to watch for confirmation.²

Sections 1.2, 4.2, 5.2, 5.3, 7.2, 8, 9, 11.2, 13, 15, 17.1, 17.2, 17.3, 18.3, 19.1, 21.2, 23, 24 and 25 are our reasoning. The succession argument and its connection to the nonstrategy benchmark, the specialist condition, the reading of the synchrony, the assessment of the eleven-factor list, the path interpretation of the practice hypothesis and the conclusion that something stopped rather than started are ours rather than sourced positions.

29. Conclusion

The standard account has DDT eliminating bed bugs and resistance bringing them back, and it cannot be right in that form, because resistant populations were reported within a few years of the compound's widespread application and the species stayed rare for five more decades.² What the record supports instead is a succession: emerging populations likely suppressed by periodic introductions of new broad-spectrum insecticides across the mid-to-late twentieth century, against a specialist parasite that lives in buildings and has nowhere else to go.² That is a sequence in the exact sense our resistance article defined, which the modelling literature calls the nonstrategy benchmark. It produced the most complete pest control outcome in this journal, and it did so because the supply of new compounds kept arriving. The strategy was ordinary; the resource it consumed was not.

The resurgence began almost synchronously in the late 1990s across three continents, and the same review that records it lists eleven contributing factors, each having probably contributed, alongside the observation that regulatory restriction had left one chemical class as the mainstay for this pest.¹ An eleven-item list is an honest statement of uncertainty and it is not an explanation. The item with a real mechanism is the shift from residual baseboard treatment to targeted baiting in the mid-1990s, which is a claim about interrupting a specific path from luggage to bed at the moment a founding population is most vulnerable.³

And a 2026 genetic study reports admixture without recurrent intercontinental gene flow and independent evolution in resurgent populations, raising the largely unexplored possibility that these are expansions from cryptic refugia that persisted through the insecticide era rather than reintroductions from distant sources.² Three continents developing populations independently and at the same time points at a change that happened in all three, which is what both the narrowing chemistry pipeline and the abandonment of residual application were. The shape of the answer, if there is one, is not that something new started. It is that something old stopped, and that nobody was counting what it had been doing.

References

1. The re-emergence of the bed bug as a nuisance pest: implications of resistance to the pyrethroid insecticides. Review article in a medical and veterinary entomology title, read as abstract. Used for the statement that a global resurgence has led to renewed scientific interest; for the finding that the current upsurge appears to have started almost synchronously in the late 1990s in Europe, the United States and Australia; for the statement that several factors have led to this situation with resistance to applied insecticides making a significant contribution; for the account that with a growing number of insecticides, three classes named, no longer available as a result of regulatory restrictions, the mainstay chemistry used for bed bug control over the past few decades has been the pyrethroid insecticides; and for the enumerated list of contributing factors, namely overcrowding in cities, poor construction and design of modern housing, more clutter and belongings in homes, an increase in centrally heated houses, denial or lack of incident reporting by hotels and landlords, increasing trade in second-hand furniture, greater reliance on communal laundries, unregulated sale, donation, importation and smuggling of second-hand clothing, changes in control practices for other pests that coincidentally controlled bed bug populations with cockroaches and ants now routinely controlled with baits rather than sprays, a worldwide increase in secondary hosts including rodents, poultry, dogs and cats, and a general decline in public awareness. https://resjournals.onlinelibrary.wiley.com/doi/10.1111/j.1365-2915.2011.01006.x
2. Admixture without recurrent intercontinental gene flow: contrasting patterns of genetic diversity and knockdown resistance profiles reveal independent evolution in resurgent common bed bug populations. Journal article in a pest science title, read as abstract and introduction extracts. Used for the framing that the species provides a striking example of pest resurgence following apparent near eradication and was a ubiquitous human ectoparasite prior to the Second World War; for the statement that following the introduction of DDT for indoor pest control, populations declined dramatically across industrialised nations; for the account that populations resistant to DDT were reported shortly after its widespread application, citing work from 1948 and 1958, and that emerging populations were likely suppressed by periodic introductions of new broad-spectrum insecticides throughout the mid-to-late twentieth century; for the statement that for nearly five decades bed bugs remained rare in developed countries with infestations considered uncommon and of minimal health concern, and that by the 1990s few pest controllers had ever encountered one; for the title's reported findings of admixture without recurrent intercontinental gene flow and independent evolution in resurgent populations; and for the description of an alternative, largely unexplored cryptic refugia hypothesis under which small populations survived in areas where insecticide exposure or efficient pest control was limited, examples given, maintaining the genetic legacies of historical colonisation. https://link.springer.com/article/10.1007/s10340-026-02089-z
3. Bed bug history and resurgence page, operated by a commercial bed bug information and services organisation. Trade source, cited as attributed material. Used for the account that bed bugs were a common problem up through the Second World War era and were virtually eradicated with the wide scale usage of named pesticides, re-emerging in the late 1990s in several named countries; for the statement that their secretive behaviour coupled with lack of public awareness has enabled efficient movement between dwellings; for the acknowledgement that no one can say for certain what caused the resurgence; for the account that in the past hotel guest rooms were typically treated on a regular basis with residual pesticides so that bed bugs introduced during travel were likely to contact pesticide as they left the luggage and travelled to the bed; for the statement that during the mid 1990s there was a dramatic shift in pest management practices, with routinely scheduled treatments of baseboards in hotels, motels and apartments replaced with targeted applications of baits for pests such as ants and cockroaches; and for the conclusion that with the absence of residual pesticide applications, bed bugs are able to travel freely and safely from the luggage to the bed and successfully begin an infestation. https://www.bedbugcentral.com/bedbugs101/history-resurgence
4. Invasion of the bedbugs, international environmental health article in an environmental health perspectives title. Used for the historical note that bed bugs are mentioned in medieval European texts and in classical Greek writings; for the statement that following the introduction of DDT in the 1950s bedbugs virtually disappeared in that country and are now making a comeback; and for the survey conducted by a national pest management association and a university with respondents from 43 countries, in which of 521 responding United States pest management companies 95 per cent reported encountering a bedbug infestation in the past year, with similar figures for Canada at 98 per cent, Europe at 92 per cent and Africa and the Middle East at 90 per cent, against only 25 per cent of United States survey respondents reporting bedbug infestations before 2000 according to a dated association press release. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2957946/
5. Popular science account of bedbug resurgence and resistance genetics. Popular science source summarising research, cited as attributed material and stating conclusions more firmly than the peer-reviewed literature we read. Used for the description that the species was so thoroughly beaten back in American and European homes by the early 1950s that entomologists openly wondered whether it was on its way to becoming a rarity in developed countries; for the statement that a young pest-control worker in London or Chicago could go an entire career without seeing one; for the assertion that genome studies show the resurgent bugs carry sodium-channel mutations inherited from the rare survivors of the original spraying campaigns; for the description of a heavily treated building as a filter in which the small resistant fraction inherits an empty environment full of hosts; and for the observation that the same kinds of sodium-channel mutations and detoxification-enzyme upregulation appear repeatedly in urban cockroaches in different cities on different continents wherever the same chemicals are used. https://terradaily.com/j-in-the-1930s-bedbugs-had-nearly-vanished-from-developed-homes-and-their-global-comeback-since-the-late-1990s-is-traced-largely-to-the-insects-evolving-resistance-to-the-very-insecticides-that-once-w/
6. Account of a 2023 European bedbug episode, general reference compilation entry. Tertiary source, flagged accordingly. Used for the statement that bedbugs were largely eradicated in the mid-twentieth century thanks to the development of strong pesticides, that a resurgence occurred in the late 1990s and has continued since, that a named persistent organic pollutants convention signed in 2004 is cited as one of the causes as the banning of powerful pesticides led to a proliferation of the parasite, and that globalisation and more frequent international travel is also frequently cited as a cause. https://en.wikipedia.org/wiki/2023_Paris_bedbug_infestation
7. Control of bed bugs, patent specification. Commercial advocacy for the claimed invention, flagged accordingly. Used for the background statement that in the developed world these insects were largely eradicated as pests in the early 1940s but have increased in prevalence since about 1995 to the extent of becoming a subject of widespread concern; for the statement that while the exact causes of the resurgence remain unclear it is variously ascribed to greater foreign travel, more frequent exchange of second-hand furnishings, a neglect of focus on countermeasures, and increasing resistance to pesticides; for the hypothesis that older, more persistent and now banned pesticides once effective against bed bugs have been removed from the market in favour of pesticides that are less environmentally persistent but also less effective; and for the observation that existing pesticides effective against most types of insects are almost universally less than fully effective against bed bugs. https://image-ppubs.uspto.gov/dirsearch-public/print/downloadPdf/9763443
8. Bed bug entry in a partisan online encyclopaedia. Source of contested general reliability, flagged prominently in the text at each use, and we could not corroborate its figures elsewhere. Used only for chronological and distributional claims, namely that significant reservoirs of infestation persisted through the insecticide period particularly in inner-city areas, that during the recession period of the 1950s infestations were mainly found in homeless shelters and prisons, that in the period 1967 to 1973 about 61 per cent of infestations were in domestic residential property and about 25 per cent in institutional settings, that a named cockroach bait active was introduced in the early 1980s providing superior effectiveness, and that this resulted in a switch from spraying, dusting and baseboard treatment to baits and insect growth regulators in the early 1990s. https://www.conservapedia.com/Bed_bug