Mental health effects from urban bed bug infestation (Cimex lectularius L.): a cross-sectional study

Annual incidence of general practice consultations related, according to the general practitioner, to bed bugs and description of cases, 2019-2020, France

Bed bug infestations have been increasing worldwide since the 2000s. Their consequences for health range from skin reactions to major psychological distress. However, epidemiological data is still lacking. This study estimated the incidence of general practice consultations related to bed bugs in France and evaluated factors associated with repercussions on everyday life. We conducted a prospective observational study from March 2019 to April 2020 among 217 GPs in France. Annual and monthly GP consultations related to bed bugs were estimated from the reported cases. Descriptive analyses were performed, and factors associated with repercussions on everyday life were assessed using a logistic regression model. The annual incidence rate of GP consultations related to bed bugs was estimated at 109 per 100,000 inhabitants [95%CI: 92-126]. Bed bug-related consultations occurred in all regions, peaking in the summer. Moderate-to-severe repercussions on everyday life were reported by 39% of the patients. The associated factors with this level of repercussions were: having seen bed bugs (OR = 4.02 [95%CI: 1.6-10.73]), having lesions from scratching (OR = 5.25 [1.65-19.92]), having lesions on the head and the neck (OR = 3.97 [1.52-10.95]) and reporting psychological distress (OR = 6.79 [2.47-20.42]). This study provides new knowledge on GP consultations related to bed bugs in France. These data will help tailor public health programs to the population's needs, including information and training for primary healthcare professionals.

Public and media interest in bed bugs-Europe 2023

In late summer of 2023 bed bug (Cimex lectularius) infestations received much media attention especially from Paris Fashion Week (2023-09-25/2023-10-03). Concern in France has grown in recent years and the public may have been sensitised from the recent release of the report Les punaises de lit: impacts, prévention et lutte from the Agence Nationale de Sécurité Sanitaire. Additionally, families returning from summer travel for the start of the school year (2023-09-04) may have brought Cimex spp. with them. A belief, typically false, that they are associated with poor housekeeping and the commercial sensitivity of infestations makes quantitative data on the occurrence and frequency of the insects difficult to find. Often it was based on the number of consultations with physicians and enquiries about bed bugs. Our study has used Google search frequency (Google Trends) to assess the growth and spread of public interest. It found that concern over the Paris outbreak spread to neighbouring countries and was an inverse function of distance. Health issues are a popular topic in science journalism and articles with bad news, threat, continuity and geographic proximity helped generate considerable media activity such that the public perceptions of the problem were enhanced and suggests that government agencies need to collect well standardised data on bed bug occurrence. Google Trends proved a sensitive tool to follow the public concern over an insect that invokes considerable dread.

Bed Bug Infestation: An Updated Review

In the past decade, there has been a global resurgence of bed bug infestations, especially in developed countries. Proper awareness and identification of bed bug infestations are essential to guide treatment and eradication. The purpose of this article is to familiarize physicians with bed bug bites so that they can effectively diagnose, treat, and address questions about bed bug bites and infestations. Bed bug bites are often painless. Typical reactions include pruritic, erythematous maculopapules occurring in clusters or in a linear or curvilinear distribution in exposed areas of the body. A small red punctum may be visualized at the center of the bite mark. Lesions that appear three in a row and papules on the upper eyelid associated with erythema and edema are highly suggestive of bites from bed bugs. Exaggerated local reactions such as vesicles, urticarial wheals, urticarial perilesional plaques, diffuse urticaria, bullae, and nodules may occur in previously sensitized individuals. Reactions to bed bug bites are self-limited. As such, treatment is mainly symptomatic. Topical pramoxine and oral antihistamines can be used to alleviate pruritus. Topical corticosteroids can be used for significant eruptions to control inflammation and pruritus, and to hasten resolution of the lesions. Integrated pest management, an approach for the eradication of bed bugs, includes monitoring devices (active monitors include the use of heat or carbon dioxide attractants and passive monitors include the use of sticky pads for trapping), and judicious use of nonchemical and chemical treatments known to be effective. Nonchemical interventions include keeping affected areas clean and free of clutter, vacuuming, washing linens with hot water, caulking wall holes and cracks where bugs can hide, proper disposal of highly infested items, and placement of bed bug traps/interceptors at the base of beds and furniture. Chemical interventions involve the use of insecticides such as synthetic pyrethroids, silicates, insect growth disruptors, carbamates, organophosphates, neonicotinoids, diethyl-meta-toluamide, chlorfenapyr, fipronil and plant essential oils. Insecticides should be used with caution to prevent over-exposure and toxicity (in particular, cardiovascular and neurologic toxicity), especially if there are young children around. It is important to note that multiple mechanisms of insecticide resistance exist and as such, chemical treatment should only be undertaken by trained professionals who understand the current literature on resistance. Both nonchemical and chemical technologies should be combined for optimal results. Bed bug infestations may cause diverse dermal reactions, stigmatization, poor self-esteem, emotional stress, anxiety, significant adverse effect on quality of life, and substantial socioeconomic burden to society. As such, their rapid detection and eradication are of paramount importance. Consultation with a professional exterminator is recommended to fully eradicate an infestation.

Perceptions of Problems with Household Insects: Qualitative and Quantitative Findings from Peri-Urban Communities in Arequipa, Peru

Vector-borne diseases continue to impose a major health burden on Peru and neighboring countries. The challenge of addressing vector-borne disease is compounded by changing social, economic, and climatic conditions. Peri-urban Arequipa is an important region to study insect infestations because of ongoing challenges with disease vectors such as triatomines and a variety of other insects. We conducted surveys (N = 1,182) and seven focus groups (average seven participants) in peri-urban Arequipa to explore knowledge of and perception toward various insects that infest the region. Focus group participants reported the presence of a wide variety of insects in and around the home, including disease vectors such as triatomines (also identified by 27.2% of survey households), mosquitoes, spiders, and bed bugs, as well as nuisance insects. Health concerns related to insects included vector-borne diseases, spider bites, allergies, and sequelae from bed bug bites, and hygiene concerns. A majority of participants in the quantitative surveys identified triatomines as the insect they were most worried about (69.9%) and could identify Chagas disease as a health risk associated with triatomines (54.9%). Insect infestations in peri-urban Arequipa present multiple burdens to residents, including injury and illness from triatomines and other insects, as well as potential mental and economic concerns related to insects such as bed bugs. Future initiatives should continue to address triatomine infestations through educational outreach and implement a more holistic approach to address the burden of both disease and nuisance insects.

A major 6 Mb superlocus is involved in pyrethroid resistance in the common bed bug Cimex lectularius

In the last few years, the bed bug Cimex lectularius has been an increasing problem worldwide, mainly due to the development of insecticide resistance to pyrethroids. The characterization of resistance alleles is a prerequisite to improve surveillance and resistance management. To identify genomic variants associated with pyrethroid resistance in Cimex lectularius, we compared the genetic composition of two recent and resistant populations with that of two ancient-susceptible strains using a genome-wide pool-seq design. We identified a large 6 Mb "superlocus" showing particularly high genetic differentiation and association with the resistance phenotype. This superlocus contained several clustered resistance genes and was also characterized by a high density of structural variants (inversions, duplications). The possibility that this superlocus constitutes a resistance "supergene" that evolved after the clustering of alleles adapted to insecticide and after reduction in recombination is discussed.

Comparative Efficacy of Superheated Dry Steam Application and Insecticide Spray Against Common Bed Bugs Under Simulated Field Conditions

The common bed bug, Cimex lectularius L., is a difficult urban pest to control. A simulated field study was conducted to compare the efficacy of steam application and an insecticide mixture spray (0.05% acetamiprid and 0.06% bifenthrin mixture) against C. lectularius. Three types of furniture (desk chair, upholstered armchair, and wooden table) were treated in the laboratory. The efficacy of the treatments was evaluated by visual inspection and placement of interceptor traps under the legs of the furniture. One hundred mixed stages of an insecticide-resistant population of C. lectularius were released onto each furniture item. After a 10-day acclimation period, each furniture item received steam treatment, insecticide spray, or no treatment. The second application of treatment was conducted 14 d later. Bed bug counts from interceptors and visual inspections were recorded at 13 d and 28 d after the initial treatment. At 28 d, the mean (± SE) live bed bug count in the steam, spray, and control group was 1 ± 0, 2 ± 1, and 83 ± 10, respectively. Both treatment methods were highly effective in controlling bed bugs on furniture. The mean bed bug count from interceptors in the steam, spray, and control groups were 0.3 ± 0.2, 11 ± 7, and 47 ± 9, respectively. There was no significant difference in the efficacy between steam and spray treatments based on either visual inspection or bed bug counts from interceptors. However, based on interceptor counts, the steam treatment caused faster bed bug population reduction than insecticide sprays.

A Case Study on Tropical Bed Bug, Cimex hemipterus (Hemiptera: Cimicidae) Infestation and Management in Dormitories

Numerous bed bug research papers have been published in the past 20 yr as a result of bed bug (Cimex spp.) (Hemiptera: Cimicidae) resurgence in the world. Yet, few of them focused on the management of the tropical bed bug, C. hemipterus (F.). Here, we describe a case of tropical bed bug infestation in two dormitory buildings and effectiveness of a tropical bed bug treatment program. The study site consisted of 125 dormitories in two buildings. An initial building-wide monitoring with ClimbUp interceptors revealed 25 infestations. The spatial distribution of bed bug infested rooms showed a significant aggregated distribution pattern with same infestation status for neighboring units sharing walls. All infested rooms were monitored every 2 wk and treated using a combination of steam and diatomaceous earth (DE) dust application if bed bugs were still found. For the 25 initially identified infested rooms, after 14 wk treatment, 44% of them no longer had bed bugs, and the mean number of bed bugs captured per room decreased by 94.1%. A combination of steam and DE dust treatment is an effective strategy for suppressing tropical bed bug infestations in dormitory environment.

Household perception and infestation dynamics of bedbugs among residential communities and its potential distribution in Africa

Bedbugs have experienced an extraordinary upsurge in the recent past across the world. This cross-sectional study aimed to explore the community perception of the pest outbreaks, the population dynamics, and dispersal patterns under different habitat systems. A survey was conducted within communities in nine counties in Kenya, where geographical coordinates of the sites of bedbug presence were recorded and maximum entropy distribution modelling (MaxEnt) was used to map and predict the potentially suitable habitat, while system thinking and system dynamics approach with Vensim PLE 8.0.9 software was applied to implement bedbug infestation dynamics. Our results indicated that majority of the respondents had ample knowledge on bedbugs and were concerned about the physico-psychologic and socio-economic health effects. Spatial distribution analysis showed regions in Kenya with optimal to suitable for bedbug occurrence in the whole country, and similar results were found at continental level across Africa. Furthermore, infestation dynamics results showed a rapid mobility of bedbug from one house to another. In terms of management strategies, the models showed that the combination of chemical with other control methods was considerably much more effective compared to the use of chemical approach only, appointing integrated pest management strategy as a better intervention approach in controlling the pest.

Histamine Excretion by the Common Bed Bug (Hemiptera: Cimicidae)

The common bed bug (Cimex lectularius L.) is a hematophagous pest species that lives in close proximity to humans. Following a blood meal, bed bugs deposit fecal material indoors. The feces contain a variety of compounds, including histamine, which serves as a component of their aggregation pheromone. Histamine is a pivotal mammalian immune modulator, and recently it was shown to be present in high concentrations in household dust from homes infested with bed bugs. To better understand the dynamics of histamine excretion, we analyzed bed bug fecal material from different life stages and populations, along with fecal material collected at different post-feeding times and from bed bugs fed on different diets. Our analysis showed significant variation in histamine excretion among life stages, with mated females excreting the most histamine and first instar nymphs excreting the least histamine. However, when histamine excretion was normalized for blood consumption, males were found to excrete more histamine than the other life stages. There was no difference in histamine excretion among laboratory and recently home-collected bed bug populations. Further, we found histamine excretion continued for at least 14 d post-feeding, with the highest amount of histamine excreted 3-4 d after a bloodmeal. Overall, this work demonstrates that bed bugs excrete histamine across all feeding life stages, populations, and at various times after feeding, and that histamine excretion is directly related to blood feeding. These results will be used to better understand the health risks associated with histamine excretion and potential mitigation strategies of environmental histamine.

Bed bugs infestation in a French university hospital: control strategy, financial impact and perspectives

BACKGROUND

With the increase of international travel and development of insecticide resistance, a reemergence of the bed bug has been observed since the 2000's and becoming a worldwide public health problem. Hospital and other medical settings haven't been spared while the cases reported remains limited. However, there is no specific recommendation for the healthcare settings emanating from learned society.

AIMS

We report our experience with a bed bug infestation of a medical unit, in the French University Hospital Center of Brest, caused by the admission of a patient carrier in October 2020. We described the practical methods we used to control bed bugs infestation, we evaluated the cost of this episode and we created a specific procedure to take care of the patients at risk or known carrier of bed bugs.

FINDINGS

The decision to close the unit for a global treatment was taken after the investigations using a sniffing dog revealed that 4 rooms were infested. The closure lasted 24 days. We estimated the total cost of the infestation to approximately 400 000 US dollars. No other wave of infestation occurred. We created a specific protocol of care for patient known carrier or at risk of carriage of bed bug to graduate strategy of control.

CONCLUSION

Bed bugs infestation in Health facilities has a major impact on the care of patients and relevant economic consequences. Prevention and education policies are an essential starting point to response to the scale of the phenomenon.

Procurement Competence and Framework Agreements for Upgraded Bed Bug Control [Cimex lectularius (Hemiptera: Cimicidae)]

The prevalence of bed bugs (Cimex lectularius L.) is increasing worldwide. Due to this increase, low-income housing owners and managers need an efficient method for controlling the pests without excessive resource use. The quality of pest control efforts is crucial for efficient eradication. Infestations often need to be approached using a variety of strategies through an integrated pest management (IPM) framework. Efficient eradication is often thought to be the responsibility of the pest control contractor alone. However, the purchase and supply management theory suggests that optimal solutions actually involve sound buyer-supplier relations to support the strategic aim of pest eradication. This study illustrates the positive outcomes of elevating pest management competence on the buyer's part. Further, this study outlines a large-scale purchase situation that quantifies bed bug control efforts, in addition to their outcomes. In total, 11,000 apartment units were observed in Oslo, Norway, over a period of six years. The release and implementation of a procurement officer together with a state-of-the-art pest management framework agreement quickly reversed the consistent escalation of bed bug infestations in the observed units. Observations revealed that the study yielded the most success in eradicating bed bugs by increasing both the number of visits to the infested apartment and the overall duration of control efforts. The improved control was achieved at a reduced cost per infested apartment unit, which allowed for the implementation of bed bug preventive measures and building-wide inspections. The observations made in this study have been discussed in the context of the impact of bed bugs in low-income communities, relative to the factors of pest burden, demography, socioeconomics, and the welfare system in Norway.

Human skin triglycerides prevent bed bug (Cimex lectularius L.) arrestment

Bed bugs (Cimex lectularius) have proliferated globally and have become one of the most challenging pests to control indoors. They are nocturnal and use multiple sensory cues to detect and orient towards their human hosts. After feeding, usually on a sleeping human, they return to a shelter on or around the sleeping surface, but not directly on the host. We hypothesized that although human skin odors attract hungry bed bugs, human skin compounds may also prevent arrestment on hosts. We used arrestment assays to test human skin swabs, extracts from human skin swabs, and pure compounds identified from human skin swabs. When given a choice, bed bugs preferred to arrest on substrates not previously conditioned by humans. These responses were consistent among laboratory-reared and apartment-collected bed bugs. The compounds responsible for this behavior were found to be extractable in hexane, and bed bugs responded to such extracts in a dose-dependent manner. Bioassay-guided fractionation paired with thin-layer chromatography, GC–MS, and LC–MS analyses suggested that triglycerides (TAGs), common compounds found on human skin, were preventing arrestment on shelters. Bed bugs universally avoided sheltering in TAG-treated shelters, which was independent of the number of carbons or the number of double bonds in the TAG. These results provide strong evidence that the complex of human skin compounds serve as multifunctional semiochemicals for bed bugs, with some odorants attracting host-seeking stages, and others (TAGs and possibly other compounds) preventing bed bug arrestment. Host chemistry, environmental conditions and the physiological state of bed bugs likely influence the dual nature behavioral responses of bed bugs to human skin compounds.

The Impact of Bedbug (Cimex spp.) Bites on Self-Rated Health and Average Hours of Sleep per Day: A Cross-Sectional Study among Hong Kong Bedbug Victims

Simple Summary

Bedbugs (Cimex spp.) are a nuisance pest of significant public health importance that is on the rise globally, especially in crowded cities such as Hong Kong. Bedbug infestations disproportionately affect underprivileged communities living in crowded and dilapidated housing. This study uses an online survey to investigate the health impacts of bedbug infestations among bedbug victims. This study found that most bedbug victims experienced ≥five bites in the past month, usually on the arms and legs. The most common reaction to bites were itchiness, redness, and swelling of the skin, and difficulties sleeping or restlessness. Bites usually occurred during sleep, impacting the bedbug victim’s mental and emotional health, and sleeping quality most severely. The adverse health outcomes of bedbug infestations were associated with the lower self-rated health and average hours of sleep per day of bedbug victims. This study brings attention to the neglected issue of bedbug infestations by providing evidence on the scope of its health impacts, informing public health interventions including public education and extermination programmes, and supportive laws and policies for adequate housing and hygiene. The successful control of bedbugs in an international city such as Hong Kong can inform the control of the global bedbug resurgence.

Abstract

Bedbugs (Cimex spp.) are a nuisance public-health pest that is on the rise globally, particularly in crowded cities such as Hong Kong. To investigate the health impacts of bedbug infestations among bedbug victims, online surveys were distributed in Hong Kong between June 2019 to July 2020. Data on sociodemographics, self-rated health, average hours of sleep per day, and details of bedbug infestation were collected. Bivariate and multivariable analysis were performed using logistic regression. The survey identified 422 bedbug victims; among them, 223 (52.9%) experienced ≥five bites in the past month; most bites occurred on the arms (n = 202, 47.8%) and legs (n = 215, 51%), and the most common reaction to bites were itchiness (n = 322, 76.3%), redness, and swelling of the skin (n = 246, 58.1%), and difficulties sleeping or restlessness (n = 125, 29.6%). Bites usually occurred during sleep (n = 230, 54.5%). For impact on daily life in the past month, most bedbug victims reported moderate to severe impact on mental and emotional health (n = 223, 52.8%) and sleeping quality (n = 239, 56.6%). Lower self-rated health (aOR < 1) was independently associated with impact on physical appearance (p = 0.008), spending money on medication or doctor consultation (p = 0.04), number of bites in the past month (p = 0.023), and irregular time of bites (p = 0.003). Lower average hours of sleep per day (aOR < 1) was independently associated with impact on mental and emotional health (p = 0.016). This study brings attention to the neglected issue of bedbug infestation by considering bedbugs as an infectious agent instead of a vector and providing empirical evidence describing its health impacts.

Investigating the association of bed bugs with infectious diseases: A retrospective case-control study

Bed bugs are common urban pests. Unlike many other blood-feeding human ectoparasites, bed bugs are not known to be vectors of human infectious diseases, but clinical and epidemiological studies to directly interrogate this link have been limited. Here, we aimed to determine whether bed bugs were associated with infectious diseases in a set of infested patients presenting to emergency departments (ED) in the greater Cleveland, OH area. We performed a retrospective case-control study involving 332 ED patients with bed bugs and 4,952 control patients, seen from February 1, 2011, through February 1, 2017. Cases and controls were matched by age, sex, and the presenting ED. Additionally, data were adjusted for ≥20 sociodemographic variables, triage data, and comorbidities in multivariable regression analyses. Seventeen laboratory values, ten different ED and inpatient diagnoses, chest radiographs, infectious disease consults, and blood cultures were examined. The odds of bed bug infestation were significantly higher for patients that had positive blood cultures, had blood cultures growing coagulase-negative Staphylococcus, were diagnosed with pneumonia, were diagnosed with cellulitis, received an infectious disease consult, received a chest radiograph, and had higher percentages of eosinophils in the blood (P < .05 for all). Additional investigations are needed to determine whether bed bugs directly contribute to disease by transmitting causative agents, whether bed bug exposure contributes secondarily contributes to infections, or whether these associations are better explained by other environmental and social determinants of health.

Pesticides Misused for Bed Bug Control: Comparing Professional and Nonprofessional Applications Reported to the National Pesticide Information Center, 2013-2017

Objectives. To compare outcomes when pesticides are used to control bed bugs by professionals and nonprofessionals. Methods. All US National Pesticide Information Center inquiries from 2013 to 2017 were assessed to identify scenarios involving bed bugs and pesticide applications. Cases were evaluated with respect to types of applicators, misapplications, and human pesticide exposures. Results. Misapplications were more than twice as likely to be reported in cases involving nonprofessional applications (14%) as in cases involving professional applications (5%). Human exposures to pesticides were reported more often when pesticides were misapplied (70%) than when there were no apparent misapplications (31%). Conclusions. Both professionals and nonprofessionals may misuse pesticides to control bed bugs, which may increase the risks of exposure and adverse outcomes. Policy interventions may reduce pesticide incidents related to bed bug control by promoting professional involvement and adherence to product label instructions.

Associations Between Bed Bugs and Mental Illness Among Emergency Department Patients

Background Bed bugs are common urban pests associated with stress, anxiety, depression, and some reports of suicidality. The emergency department (ED) treats patients with both acute mental illness and bed bug infestations. There have been few studies examining associations between bed bug infestations and mental illness. Methods A case-control study involving 332 adult ED patients infested with bed bugs and 4,952 uninfested control patients matched on sex, age (±1 year at the time of the ED visit), and the specific ED was completed. All clinic encounters occurred in northeast Ohio between February 1, 2011, and February 1, 2017, from a single health system. Univariable and multivariable regression analysis looked for associations between bed bug infestation and different psychiatric diagnoses and medications. Results Bed bug infested patients were more likely than uninfested patients to screen positive for an unsafe home and needing an abuse consult at ED triage (P≤.03 for both). ED psychiatric evaluations were not significantly more common among those with (2.4%) and without (1.3%) bed bugs (P=.14). Bed bug infested patients were significantly more likely to have an ED or inpatient diagnosis of alcohol abuse and psychosis (P≤.03 for both), but not for depression or suicidality. On univariable analysis, among ED patients not admitted to the hospital, bed bug infested patients were more likely to be diagnosed with psychosis or schizophrenia/schizoaffective disease (P≤.02) than uninfested patients. Among ED patients that received an ED or inpatient psychiatric evaluation and were admitted to the hospital, bed bug infested patients were significantly less likely to be diagnosed with depression and suicidality (P≤.03 for both). However, they were not significantly more likely to have insomnia or anxiety. Discussion Among ED patients, bed bug infestations were not associated with an ED or inpatient diagnosis of depression or suicidality. On univariable analysis, some mental health diagnoses such as anxiety and insomnia were more common among ED patients with bed bugs, but these associations were no longer significant on multivariable analysis. These associations likely reflect the complex relationships between socioeconomic factors, health disparities, mental illness, and having a bed bug infestation.

Dermatologic aspects of bed bug epidemic: an atlas of differential diagnosis

Bed bug infestation rate has gone through an unforeseen increase in the past decades worldwide. Their resurgence is a consequence of numerous factors, including growing population density, increased international travel and the spread of insecticide resistance. Bed bug infestation is often revealed by skin symptoms appearing after their bite in sensitive patients. Medical professionals encountering patients with bed bug bites have responsibility for recognizing the condition and for instructing patients about the necessary measures for eradication. Setting the correct diagnosis, however, is not unequivocal as several skin diseases with autoimmune, immune-mediated aetiology or other arthropod stings and bites may present with similar symptoms. In this review we provide a differential diagnostic guide and an atlas of clinical pictures assigned to the diagnoses. We highlight those dermatological findings where the possibility of bed bug bite arises and identify key elements that help in the differentiation so as to avoid unnecessary diagnostic tests and force early start of extermination.

The Role of Antennae in Heat Detection and Feeding Behavior in the Bed Bug (Hemiptera: Cimicidae)

The common bed bug (Cimex lectularius L.) is an obligate hematophagous ectoparasite that has significant impacts on human health and well-being. All life stages of bed bugs (except eggs) feed solely on blood, which is required to molt and reproduce. Bed bugs use multiple cues to locate their hosts, including heat, CO2, and body odors. Of these cues, detection of heat appears limited to a short distance of <3 cm. However, it remains unclear if bed bugs can detect radiant heat, what structure(s) are responsible for heat detection, and if heat detection via the antennae is required for feeding. In this study, bed bug response to radiant heat was evaluated using the two-choice T-maze assay with the heat source either in contact with the surface (i.e., conduction) or not in contact (i.e., radiation) in nonantennectomized bed bugs. Further, we systematically ablated the bed bug's antennal segments (distal tip, first segment, and all four segments) and assessed their responses to heat and feeding in a unique two-choice T-maze assay and individual feeding assays, respectively. Our two-choice assays with contact to or no contact with the surface indicated that bed bugs cannot detect radiant heat. Later, we found that the distal tip of the terminal antennal segment is responsible for orientation toward a heat source. However, >50% of the bed bugs fed even when the entire antenna was removed, suggesting redundancy in sensory cues that drive feeding. These results will be used to better understand the role heat plays in bed bug host attraction and design of traps.

Bed bugs shape the indoor microbial community composition of infested homes

Indoor pests, and the allergens they produce, adversely affect human health. Surprisingly, however, their effects on indoor microbial communities have not been assessed. Bed bug (Cimex lectularius) infestations pose severe challenges in elderly and low-income housing. They void large amounts of liquid feces into the home environment, which might alter the indoor microbial community composition. In this study, using bed bug-infested and uninfested homes, we showed a strong impact of bed bug infestations on the indoor microbial diversity. Floor dust samples were collected from uninfested and bed bug-infested homes and their microbiomes were analyzed before and after heat interventions that eliminated bed bugs. The microbial communities of bed bug-infested homes were radically different from those of uninfested homes, and the bed bug endosymbiont Wolbachia was the major driver of this difference. After bed bugs were eliminated, the microbial community gradually shifted toward the community composition of uninfested homes, strongly implicating bed bugs in shaping the dust-associated environmental microbiome. Further studies are needed to understand the viability of these microbial communities and the potential risks that bed bug-associated microbes and their metabolites pose to human health.

Prevalence and Spatial Distribution of Bed Bug, Cimex lectularius, Infestation in Southwest of Iran: GIS Approach

Background:

The common bed bug, a nocturnal bloodsucking insect, is known as a human parasite and public health problem in the world. The prevalence and geographical dispersion of bed bug in Ahvaz City, southwest of Iran was measured.

Methods:

Spatial distribution of Cimex lectularius was determined by surveying 520 houses in 62 areas of Ahvaz City in 2017. Some information like as infested points, the concern level of the residents and allergic reaction to the insect bite were registered in a form using the secondhand instrument.

Results:

According to the spatial distribution map, of 62 areas, 27 of them are infested with bed bugs. Infestation is scattered throughout the city, but its focus is on the east of the Karun River. The most bed bug infestation was in Asiabad followed by Manbaab areas. Prevalence of bed bug infestation estimated 9.61% in Ahvaz city. It was 5.4% and 11.6% in apartments and single houses, respectively. The lowest and highest infestation rates based on its source were 1.35% and 9.03% in wallpaper and cracks and crevices, respectively. Bedroom and sitting room were the main harborages for bed bug in the houses. The majority of residents who had bitten by a bed bug showed various allergic reactions like redness skin, papules, vesicles, pustules and blisters. Most of the people in the infested houses (62%) were very concern about bed bug infestation.

Conclusion:

Public education and increasing the knowledge of people can lead to successful management, prevention and elimination of this nuisance pest.

Evaluation of a Non-Chemical Compared to a Non-Chemical Plus Silica Gel Approach to Bed Bug Management

Bed bug resistance to commonly used pesticide sprays has led to exploring new pesticides and other strategies for bed bug management. Non-chemical methods are effective in bed bug management; however, they do not provide residual protection. Compared to insecticide sprays, dust formulations are considered to provide longer residual control. We evaluated two bed bug management programs in apartment buildings. A building-wide inspection was initially conducted to identify bed bug infested apartments. Selected apartments were divided into two treatment groups: non-chemical plus silica gel dust treatment (10 apartments) and non-chemical treatment (11 apartments). After initial treatment, apartments were re-visited monthly for up to 6 months. During each visit, the total bed bug count per apartment was obtained by examining interceptor traps placed in the apartments and conducting a visual inspection. Mean bed bug count was reduced by 99% and 89% in non-chemical plus silica gel dust and non-chemical treatment, respectively. Non-chemical plus silica gel dust treatment caused significantly higher bed bug count reduction than the non-chemical treatment at 6 months. Bed bugs were eradicated from 40% and 36% of apartments treated with non-chemical plus silica gel dust treatment and non-chemical treatment, respectively.

Insecticidal Activity of Doxycycline against the Common Bedbug

There is an ongoing need for safe and effective anti-bedbug compounds. Here, we tested the toxicity of three antimicrobial agents against bedbugs when administered orally. We reveal that doxycycline has direct insecticidal activity at 250 μg/ml (0.025%) that is particularly strong against immature bedbugs and appears to be independent of antimicrobial activity. Future studies to determine the mechanisms behind this property could be useful for the development of orally active insecticides or anti-bedbug therapeutics.

Fumigation Activities of Methyl Benzoate and Its Derivatives Against the Common Bed Bug (Hemiptera: Cimicidae)

Common bed bug Cimex lectularius (L.) (Hemiptera: Cimicidae) infestations are on the rise and due to the development of pesticide resistance they are becoming more difficult to control, affordably. We evaluated a naturally occurring compound methyl benzoate (MB) and related analogs, previously reported to have insecticidal activity on several agricultural pests, for its fumigant action on the common bed bug, C. lectularius L. A discriminating concentration was used to determine the effectiveness of MB, and several of its analogs as fumigants in a laboratory assay. It was found that MB provided >90% control of adult bed bugs in this laboratory fumigant assay. LC50 values were calculated for MB against both a pyrethroid-susceptible and a pyrethroid-resistant strain of common bed bugs. It was determined that both strains were susceptible in this laboratory assay. However, when MB was tested in a field-like assay and compared to a commercially available bed bug control product, it was found to be significantly less effective compared to the commercial product. Our study has found that while MB has the potential to be used as a bed bug control agent, refinements in the delivery system will be needed to increase efficacy under field-like conditions.

Insecticide resistance mechanisms with novel 'kdr' type gene mutations in the tropical bed bug Cimex hemipterus

BACKGROUND

The tropical bed bug, Cimex hemipterus, is a serious indoor public health pest in tropical regions causing intense physical discomfort and mental distress to humans. At present, the application of insecticides is the major control strategy. The present study was designed to evaluate the development of resistance and resistance mechanisms in Cimex hemipterus from Kandy district, Sri Lanka.

METHODS

The resistance status of the collected bed bugs was determined against the discriminative dosages of DDT, malathion, propoxur, deltamethrin and permethrin by conducting bioassays according to World Health Organization guidelines. Activities of insecticide metabolizing enzymes, i.e. esterases, glutathione S-transferases (GST) and monooxygenases, and the insensitivity of organophosphate/carbamate target site acetylcholinesterase (AChE), were evaluated by biochemical assays. Regions of the gene of the pyrethroid/DDT target site, the voltage-gated sodium channel regulatory protein (VGSC), were sequenced for possible kdr mutations.

RESULTS

Survival percentages of bed bug population were 71, 68 and 51% for DDT, malathion and propoxur respectively. KT50 and KT90 values, calculated using log-probit mortality curves for deltamethrin were 62.55 and 123.96 h, respectively. These values were much higher for permethrin where KT50 was 201.10 h and the KT90 was beyond the detectable range. Results were compared with previous values reported for the same population in 2002. Resistance to propoxur has increased significantly from 11 to 51% with about a 20-fold increase in the number of individuals with elevated esterase mechanism. No significant change has occurred in malathion and DDT resistance, in GST and monooxygenase activities, and in AChE sensitivity for the past 14 years. Six kdr associated mutations (Y/L995H, V1010L, I1011F, L1014F, V1016E, L1017F/S) and a non-kdr associated mutation (A1007S mutation) were found from the α-region of the VGSC gene. Out of the kdr type mutations, only L1014F has been reported previously form C. hemipterus while the others have been reported from other insects.

CONCLUSIONS

The bed bug population has developed high resistance to propoxur with increased esterase activities. KT50 for deltamethrin and permethrin has increased 125- and 20-fold, respectively, over the period 2002 to 2016. To the authors' knowledge, this is the first time that the possible involvement of a kdr type mutation in developing pyrethroid resistance in C. hemipterus has been shown in Sri Lanka.

Characteristics of Bed Bug Infested Patients in the Emergency Department

Cimex lectularius L., the common bed bug, is a hematophagous human ectoparasite that has undergone a global resurgence in the past two decades. We surveyed 706 active emergency department (ED) patients about their experiences with bed bugs. We found that 2% of ED patients reported having a current bed bug infestation, significantly more than the historical number of ED patients upon which we find bed bug; 37% of ED patients report previously having been fed on by a bed bug; 15% currently know someone with an active infestation; and 59% know someone that has had an infestation within ≤ 5 years. Only 18% of bed bug infested patients reported their infestation to emergency medicine providers and only 21% were put in isolation precautions. We found that 25% of patients with bed bugs worried about receiving worse healthcare because of their infestation. Persons with bed bugs were more likely compared to those without bed bugs to be older (52 vs. 41 years) and arrive by ambulance (57% vs. 14%) (p < 0.05), but not reporting insomnia (50% vs. 49%) (p = 1.0). Bed bug infested patients can be common in the ED. Most bed bug infested patients are older, arrive to the ED by ambulance, do not report their infestation to healthcare providers, and are not adequately placed into isolation precautions, potentially putting other patients and providers at risk for acquiring the infestation.

Dynamics of bed bug infestations and control under disclosure policies

Bed bugs are household pests that bite humans and cause myriad medical, psychological, social, and economic problems. Infestation levels have resurged across the United States in recent decades, and cities and states are debating strategies to deal with them. Here, we introduce a mathematical model to study the spread of bed bugs and predict the costs and benefits of policies aimed at controlling them. In particular, we evaluate disclosure, a policy that requires landlords to notify potential tenants of recent infestations in a unit. While disclosure aims to protect individual tenants, our results suggest that these policies also reduce infestation prevalence market-wide. Disclosure results in some initial cost to landlords but leads to significant savings in the long term.

Bed bugs have reemerged in the United States and worldwide over recent decades, presenting a major challenge to both public health practitioners and housing authorities. A number of municipalities have proposed or initiated policies to stem the bed bug epidemic, but little guidance is available to evaluate them. One contentious policy is disclosure, whereby landlords are obligated to notify potential tenants of current or prior bed bug infestations. Aimed to protect tenants from leasing an infested rental unit, disclosure also creates a kind of quarantine, partially and temporarily removing infested units from the market. Here, we develop a mathematical model for the spread of bed bugs in a generalized rental market, calibrate it to parameters of bed bug dispersion and housing turnover, and use it to evaluate the costs and benefits of disclosure policies to landlords. We find disclosure to be an effective control policy to curb infestation prevalence. Over the short term (within 5 years), disclosure policies result in modest increases in cost to landlords, while over the long term, reductions of infestation prevalence lead, on average, to savings. These results are insensitive to different assumptions regarding the prevalence of infestation, rate of introduction of bed bugs from other municipalities, and the strength of the quarantine effect created by disclosure. Beyond its application to bed bugs, our model offers a framework to evaluate policies to curtail the spread of household pests and is appropriate for systems in which spillover effects result in highly nonlinear cost–benefit relationships.

Bed Bug (Hemiptera: Cimicidae) Attraction to Human Odors: Validation of a Two-Choice Olfactometer

Bed bugs (Cimex lectularius L.) (Hemiptera: Cimicidae) are obligate hematophagous ectoparasites, and, therefore, must locate suitable hosts to ensure survival and reproduction. Their largely nocturnal activity suggests that chemosensory and thermosensory cues would play critical roles in host location. Yet, the importance of olfaction in host attraction of bed bugs remains unclear. We developed and validated a Y-tube, two-choice olfactometer and tested its suitability for investigating attraction to human odors (from skin swabs). Olfactometer orientation significantly affected the percentage of bed bugs that were activated by human odors, with significantly more bed bugs responding when the olfactometer was oriented vertically (bug introduced at bottom of the olfactometer) compared with all other orientations. Starved (7-10 d) adult males, mated females, and nymphs responded (47-77% moved up the olfactometer and made a choice) when human odors were present in the olfactometer, while starved, unmated females did not respond. Skin swabs from all five human participants elicited high response rates (65-82%), and bed bugs from four different populations responded to skin swabs (40-82% response rate). However, in all assays including those resulting in relatively low response rates, bed bugs exhibited >90% preference for human odors over blank controls. These results provide strong evidence that bed bugs can respond and orient towards human odors, independently of all other host cues. Furthermore, the validated olfactometer should enable rapid and efficient evaluations of bed bug behavioral responses to semiochemicals.

Effectiveness of Boric Acid by Ingestion, But Not by Contact, Against the Common Bed Bug (Hemiptera: Cimicidae)

Boric acid has been used as an insecticide in the successful control of agricultural, public health and urban pests long before the advent of synthetic organic pesticides. Boric acid products, formulated as dusts, sprays, granular baits, pastes, gels, and liquids, are widely available to consumers and pest management professionals, especially to control pest infestations within homes. Boric acid dust is commonly used against bed bugs (Cimex lectularius L. [Hemiptera: Cimicidae]), but its efficacy has not been demonstrated. We evaluated the efficacy of boric acid as an ingestible and residual contact insecticide on bed bugs, and compared its efficacy on the German cockroach (Blattella germanica L. [Blattodea: Ectobiidae]) which is known to be susceptible to boric acid by both routes. Dose-response studies of 0-5% boric acid in blood demonstrated that ingested boric acid caused rapid mortality at concentrations of ≥2%, and even 0.5% and 1% boric acid caused 100% mortality, albeit at a slower time course. In contrast, bed bugs survived contact with high concentrations of boric acid dust. Smaller boric acid particles did not increase mortality of either unfed or recently fed bed bugs. The same boric acid products were effective at causing mortality of German cockroaches by both contact and ingestion. We thus conclude that although boric acid is an excellent candidate active ingredient for an ingestible bait formulation, residual applications of dust or spray would be ineffective in bed bug interventions.

Mental health effects caused by red imported fire ant attacks (Solenopsis invicta)

Susceptible individuals who have suffered painful stings caused by red imported fire ants, Solenopsis invicta, usually experience physical health effects such as fever, dizziness, generalized urticaria, or other systemic reactions such as anaphylactic shock. Whether S. invicta stings also have negative effects on mental health is not clear. In the present study, the psychological impact of S. invicta stings was evaluated using a questionnaire that included a previously published posttraumatic stress disorder (PTSD) checklist, the Patient Health Questionnaire 9-item (PHQ-9), the Generalized Anxiety Disorder 7-item (GAD-7) scale, the Beck Anxiety Inventory (BAI), and the Pittsburgh Sleep Quality Index, 5th scale (PSQI(5)). A total of 96 valid questionnaires were obtained; 37 participants were placed in the stung group, and 59 participants were placed in the unstung group. Our results showed that symptoms of anxiety, depression and sleep disturbances were not associated with S. invicta stings (for GAD-7 scale, Pearson Chi-Square test, χ² = 0.152, df = 1, P = 0.697; for the BAI, χ² = 2.252, df = 1, P = 0.133; for the PHQ-9, χ² = 0.098, df = 1, P = 0.754; for the PSQI(5), χ² = 0.536, df = 1, P = 0.453). In total, 2 of 83 individuals stung by S. invicta met the criteria (>50) for PTSD. However, there was no significant difference on PTSD between those stung by S. invicta in the 30-day group and the over 30-day group (χ² = 0.318, df = 1, P = 0.573). Overall, our data do not show an effect of S. invicta stings on mental health as measured using a range of indicators.

Dynamics of bed bug infestations in three low-income housing communities with various bed bug management programs

BACKGROUND

Infestations of the common bed bug, Cimex lectularius L., have become common in low-income communities in the USA over the last 15 years. We evaluated community-based integrated pest management (IPM) programs for reducing bed bug infestations. Two housing authorities (Bayonne and Hackensack) implemented bed bug IPM programs. A third housing authority (Paterson) was used as the control site. Building-wide surveys were conducted in all communities, three times, to evaluate the effectiveness of the IPM programs.

RESULTS

From 0 to 24 months, the infestation rate at Bayonne, Hackensack, and Paterson decreased by 49, 64, and 26%, respectively. The two sites that adopted IPM achieved faster bed bug elimination than the control site. The bed bug introduction rate over a 24-month period at Bayonne, Hackensack, and Paterson was 7, 3, and 11%, respectively. The introduction rate was positively associated with the initial infestation rate. Residents from buildings enrolled in IPM programs were more satisfied with the bed bug control services than residents from the control site.

CONCLUSION

IPM programs were more effective in reducing bed bug infestations than traditional pest control services, but many factors contributed to the lower than desired level of reduction in infestation rate. © 2017 Society of Chemical Industry.

Functional characterization of Aquaporin-like genes in the human bed bug Cimex lectularius

The bed bug Cimex lectularius is a blood-feeding re-emerging annoyance pest insect that has the ability to transmit Trypanosoma cruzi under experimental laboratory conditions. Aquaporins (AQPs) are water channel proteins that are essential in biological organisms. C. lectularius are constantly exposed to water-related stress, suggesting that AQPs may offer novel control avenues. We identified and cloned four AQPs from C. lectularius, assessed tissue and lifestage-specific expression, and characterized biochemical functions in vitro and in vivo. We identified an efficient water-specific AQP (ClAQP1), two aquaglyceroporins (ClGlp1 and ClGlp2) and a homolog of Drosophila melanogaster big brain (ClBib). ClGlp1 was only functional when co-expressed with the water-specific AQP. Simultaneous RNAi gene silencing of ClAQP1 and ClGlp1 significantly reduced water and urea excretion post blood feeding. The Bib homologue was enriched in embryos, exclusively expressed in ovaries, and when silenced, dramatically increased bug fecundity. Our data demonstrate that AQPs have critical roles in excretion, water homeostasis and reproduction in C. lectularius, and could be potential targets for control in this notorious pest.

Comparison of ingestion and topical application of insecticides against the common bed bug, Cimex lectularius (Hemiptera: Cimicidae)

BACKGROUND

The global prevalence of Cimex lectularius infestations has challenged current intervention efforts, as pyrethroid resistance has become ubiquitous, availability of labeled insecticides for bed bugs is limited, and non-chemical treatment options, such as heat, are often unaffordable. We evaluated representative insecticides toward the goal of developing a novel, ingestible liquid bait for hematophagous arthropods.

RESULTS

LC₅₀ values were estimated for adult males and first instar nymphs of an insecticide-susceptible strain for abamectin, clothianidin, fipronil and indoxacarb, after ingestion from an artificial feeder. LD₅₀ values were calculated based on the ingested blood volume. Ingested abamectin, clothianidin and fipronil caused rapid mortality in both life stages. Fipronil was ∼43-fold more effective by ingestion than by topical application. Indoxacarb and its bioactive metabolite decarbomethoxylated JW062 (DCJW) were ineffective at causing bed bug mortality even at concentrations as high as 1000 ng mL^-1 blood.

CONCLUSIONS

Fipronil, clothianidin and abamectin have potential for being incorporated into a liquid bait for bed bug control; indoxacarb and DCJW were not effective. Bed bugs are a good candidate for an ingestible liquid bait because systemic formulations generally require less active ingredient than residual sprays, they remain contained and more effectively target hematophagous arthropods. © 2016 Society of Chemical Industry.

Pesticide Vendors in the Informal Sector: Trading Health for Income

South African low-income communities face many challenges (e.g., insufficient housing, poor service delivery, and abject poverty); additionally, a silent challenge of pest infestation plagues these areas resulting in disease risks, nuisances, and stigma. Consequently, an enterprising urban informal sector business has emerged providing residents with highly toxic, effective, cheap, and illegal "street pesticides." These pesticides pose acute and chronic health risks for vendors and residents. The economic opportunity provided by the high demand for effective and cheap pest control results in the high risk of health effects being traded for income. Current measures to control and "regulate" the massive street pesticide sales result in toxic stockpiles and government's "turning a blind eye." Solutions will only be achieved through open dialog identifying and developing non-toxic pest control strategies while ensuring vendors' income; and relevant stakeholder recognition that pest infestation is a social and environmental health determinant needing acknowledgement in different government policies.

Effects of Various Interventions, Including Mass Trapping with Passive Pitfall Traps, on Low-Level Bed Bug Populations in Apartments

Two experiments were conducted to evaluate the effects of various interventions on low-level bed bug, Cimex lectularius L., populations in occupied apartments. The first experiment was conducted in occupied apartments under three intervention conditions: never treated (Group I), recently treated with no further treatment (Group II), and recently treated with continued treatment (Group III). Each apartment was monitored with pitfall-style traps (interceptors) installed at beds and upholstered furniture (sleeping and resting areas) along with ∼18 additional interceptors throughout the apartment. The traps were inspected every 2 wk. After 22 wk, bed bugs had been eliminated (zero trap catch for eight consecutive weeks and none detected in visual inspections) in 96, 87, and 100% of the apartments in Groups I, II, and III, respectively. The second experiment investigated the impact of interceptors as a control measure in apartments with low-level infestations. In the treatment group, interceptors were continuously installed at and away from sleeping and resting areas and were inspected every 2 wk for 16 wk. In the control group, interceptors were placed in a similar fashion as the treatment group but were only placed during 6–8 and 14–16 wk to obtain bed bug counts. Bed bug counts were significantly lower at 8 wk in the treatment group than in the control group. At 16 wk, bed bugs were eliminated in 50% of the apartments in the treatment group. The implications of our results in the development of bed bug management strategies and monitoring protocols are discussed.

Mortality, temporary sterilization, and maternal effects of sublethal heat in bed bugs

Adult bed bugs were exposed to the sublethal temperatures 34.0°C, 35.5°C, 37.0°C, 38.5°C, or 40.0°C for 3, 6, or 9 days. The two uppermost temperatures induced 100% mortality within 9 and 2 days, respectively, whereas 34.0°C had no observable effect. The intermediate temperatures interacted with time to induce a limited level of mortality but had distinct effects on fecundity, reflected by decreases in the number of eggs produced and hatching success. Adult fecundity remained low for up to 40 days after heat exposure, and the time until fertility was restored correlated with the temperature-sum experienced during heat exposure. Three or 6 days of parental exposure to 38.5°C significantly lowered their offspring’s feeding and moulting ability, which consequently led to a failure to continue beyond the third instar. Eggs that were deposited at 22.0°C before being exposed to 37.0°C for 3 or 6 days died, whereas eggs that were exposed to lower temperatures were not significantly affected. Eggs that were deposited during heat treatment exhibited high levels of mortality also at 34.0°C and 35.5°C. The observed negative effects of temperatures between 34.0°C and 40.0°C may be utilized in pest management, and sublethal temperature exposure ought to be further investigated as an additional tool to decimate or potentially eradicate bed bug populations. The effect of parental heat exposure on progeny demonstrates the importance of including maternal considerations when studying bed bug environmental stress reactions.

Field Study of the Comparative Efficacy of Three Pyrethroid/Neonicotinoid Mixture Products for the Control of the Common Bed Bug, Cimex lectularius

Three insecticide mixtures that contain two classes of insecticides (pyrethroid and neonicotinoid) were recently developed to control bed bugs. We evaluated three integrated bed bug management strategies in apartments, each using the same non-chemical control methods and one of the three insecticide mixture products: Tandem (lambda-cyhalothrin + thiamethoxam), Temprid SC (beta-cyfluthrin + imidacloprid), and Transport Mikron (bifenthrin + acetamiprid). No insecticides were applied in the Control apartments. In all apartments, we installed vinyl mattress encasements (if not already present) and applied steam to beds and other infested upholstered furniture. Insecticide sprays were applied in the three treatments. Each treatment and the Control included 8–10 occupied apartments. Re-treatment was conducted during biweekly inspections if necessary. After eight weeks, the mean (± SEM) bed bug count reduction in the Tandem, Temprid SC, Transport Mikron, and Control was 89 ± 9, 87 ± 6, 98 ± 1, and 23 ± 54%, respectively. Only Tandem and Transport Mikron treatments resulted in significantly higher population reduction than the Control at eight weeks. There were no significant differences in mean percent reduction among the three treatments (Tandem, Temprid SC, Transport Mikron) at eight weeks. Tandem spray caused significantly faster bed bug reduction than Temprid SC spray and Transport Mikron spray.

Insecticide Resistance in Eggs and First Instars of the Bed Bug, Cimex lectularius (Hemiptera: Cimicidae)

Two strains of the common bed bug, Cimex lectularius L., eggs and first instars collected from pyrethroid-resistant adults were evaluated for insecticide resistance and compared to a susceptible strain. Dose-response bioassays were conducted using two insecticide formulations (Temprid: imidacloprid/β-cyfluthrin, and Transport: acetamiprid/bifenthrin). The lethal concentration (LC₅₀) for the two resistant egg strains exposed to imidacloprid/β-cyfluthrin ranged from 3 to 5-fold higher than susceptible strain eggs. Resistant strain eggs dipped into formulations of acetamiprid/bifenthrin had LC₅₀ values which were significantly greater (39 to 1,080-fold) than susceptible strain eggs. Similar to eggs, resistant strain first instars exposed to residual applications of imidacloprid/β-cyfluthrin had LC₅₀ values ranging from 121 to 493-fold greater than susceptible strain first instars. When resistant strain first instars were treated with acetamiprid/bifenthrin, they had LC₅₀ values that were 99 to >1,900-fold greater than susceptible strain first instars. To determine differences between egg and first instar resistance, stage resistance ratios (SRR) were compared between the two stages. There was little difference between the egg and first instar stages, indicated by small SRR values ranging from 1.1 to 10.0. This study suggests that insecticide resistance is expressed early during bed bug development.

Status of Urban Bed Bug Infestations in Southern China: An Analysis of Pest Control Service Records in Shenzhen in 2012 and Dongguan in 2013

The recent resurgence of bed bugs (Cimex spp.) in many developed countries has drawn increasing attention worldwide. The status of urban bed bug infestations were investigated in Shenzhen and Dongguan, two major cities in southern Guangdong Province of southern China, based on pest control service records from two different companies (one during 2012 and another during 2013). The results showed that Shenzhen and Dongguan have a severe problem with bed bug infestations: the control of bed bugs is a constant concern, except during the winter. In Shenzhen, a similar number of premises were treated for bed bugs in central business districts and suburban districts. However, in Dongguan, more premises were treated for bed bugs in suburban districts than in central business districts. The treatment rate for worker sleeping quarters, apartments, hotel, and private houses in Shenzhen was 53.8, 43.0, 1.9, and 1.3%, respectively. The percentage of treated rooms was 56.1% for worker sleeping quarters and 91.1% for apartments. In Dongguan, the treatment rate for worker sleeping quarters, apartments, hotel, and private houses was 90.0, 10.0, 0.0, and 0.0%, respectively.

The odorant receptor co-receptor from the bed bug, Cimex lectularius L

Recently, the bed bug, Cimex lectularius L. has re-emerged as a serious and growing problem in many parts of the world. Presence of resistant bed bugs and the difficulty to eliminate them has renewed interest in alternative control tactics. Similar to other haematophagous arthropods, bed bugs rely on their olfactory system to detect semiochemicals in the environment. Previous studies have morphologically characterized olfactory organs of bed bugs’ antenna and have physiologically evaluated the responses of olfactory receptor neurons (ORNs) to host-derived chemicals. To date, odorant binding proteins (OBPs) and odorant receptors (ORs) associated with these olfaction processes have not been studied in bed bugs. Chemoreception in insects requires formation of heteromeric complexes of ORs and a universal OR coreceptor (Orco). Orco is the constant chain of every odorant receptor in insects and is critical for insect olfaction but does not directly bind to odorants. Orco agonists and antagonists have been suggested as high-value targets for the development of novel insect repellents. In this study, we have performed RNAseq of bed bug sensory organs and identified several odorant receptors as well as Orco. We characterized Orco expression and investigated the effect of chemicals targeting Orco on bed bug behavior and reproduction. We have identified partial cDNAs of six C. lectularius OBPs and 16 ORs. Full length bed bug Orco was cloned and sequenced. Orco is widely expressed in different parts of the bed bug including OR neurons and spermatozoa. Treatment of bed bugs with the agonist VUAA1 changed bed bug pheromone-induced aggregation behavior and inactivated spermatozoa. We have described and characterized for the first time OBPs, ORs and Orco in bed bugs. Given the importance of these molecules in chemoreception of this insect they are interesting targets for the development of novel insect behavior modifiers.

Blood constituents as phagostimulants for the bed bug Cimex lectularius L

Many hematophagous arthropods are stimulated by blood constituents to initiate feeding. We used a membrane-based feeding system to identify chemicals that stimulate acceptance and engorgement responses in various life stages of bed bugs. Water was fortified with a variety of compounds (e.g. salts, amino acids, vitamins, nucleotides, cholesterol and fatty acids) in these bioassays. ATP was the most effective phagostimulant in adults and nymphs, resulting in >70% of bed bugs fully engorging. Addition of NaCl to low ATP solutions that alone elicited <50% engorgement significantly enhanced feeding responses of bed bugs. A comparison of feeding responses with solutions of various adenine nucleotides showed that ATP was more stimulatory than ADP, which was more effective than AMP. Feeding assays with physiological levels of other blood constituents such as d-glucose, albumin, globulin, cholesterol and mixtures of vitamins and amino acids did not stimulate engorgement, suggesting that adenine nucleotides are the most important feeding stimulants in bed bugs. Identification of phagostimulants for bed bugs will contribute towards the development of artificial diets for rearing purposes, as well as for the development of alternative methods to eliminate bed bug infestations.