Genome of tropical bed bug Cimex hemipterus (Cimicidae, Hemiptera) reveals tetraspanin expanded in bed bug ancestor.

Cimex species are ectoparasites that exclusively feed on warm-blooded animals such as birds and mammals. Three cimicid species are known to be persistent pests for humans, including the tropical bed bug Cimex hemipterus, common bed bug Cimex lectularius, and Eastern bat bug Leptocimex boueti. To date, genomic information is restricted to the common bed bug C. lectularius, which limits understanding their biology and to provide controls of bed bug infestations. Here, a chromosomal-level genome assembly of C. hemipterus (495 Mb [megabase pairs]) contained on 16 pseudochromosomes (scaffold N50 = 34 Mb), together with 9 messenger RNA and small RNA transcriptomes were obtained. In comparison between hemipteran genomes, we found that the tetraspanin superfamily was expanded in the Cimex ancestor. This study provides the first genome assembly for the tropical bed bug C. hemipterus, and offers an unprecedented opportunity to address questions relating to bed bug infestations, as well as genomic evolution to hemipterans more widely.

Efficacy of a topical product combining esafoxolaner, eprinomectin and praziquantel against bedbug (Cimex lectularius) experimental infestations in cats.

Bedbugs (Cimex lectularius) are a persistent nuisance pest for humans and their home environment, and may also opportunistically feed on other mammals, including household pets like dogs and cats. NexGard® Combo is a topical endectoparasiticide product for cats combining esafoxolaner, an isoxazoline compound with insecticidal and acaricidal properties, the nematocide eprinomectin and the cestocide praziquantel. The insecticidal efficacy of this product was evaluated in cats experimentally infested with C. lectularius in a blinded, negative controlled and randomized study. Two groups of 7 cats were formed: an untreated control group, and a NexGard® Combo group treated once on Day 0 at the label dose. Cats were then challenged weekly, each with twenty unfed adult C. lectularius, on Days 1, 7, 14, 21 and 28. After close contact with the cat's skin for 15 min, live fed C. lectularius were collected and incubated for 96 h. The weekly efficacy evaluations were based on a comparison of the number of surviving bedbugs in the control and the treated group after 48, 72 and 96 h of incubation. The model was demonstrated to be robust as in the control group the average feeding rate after the 15-minute challenge was 94%, and as 96% of incubated bed bugs were alive after 96 hours of incubation. Significant live bedbug reductions were demonstrated in the Nexgard® Combo treated group: after 96 h of incubation, the reductions ranged from 80.6 to 88.0% during the Day 1 to Day 21 period, and dropped to 58% at Day 28.

Title: Efficacité d'une formulation topique associant esafoxolaner, éprinomectine et praziquantel contre les infestations expérimentales par les punaises de lit (Cimex lectularius) chez le chat. Abstract: Les punaises de lit (Cimex lectularius) sont une nuisance persistante pour les humains et leur environnement domestique, et peuvent également se nourrir de manière opportuniste d'autres mammifères, y compris les animaux domestiques comme les chiens et les chats. NexGard® Combo est une formulation topique endectoparasiticide pour chats associant l'esafoxolaner, un composé d'isoxazoline à propriétés insecticides et acaricides, le nématodicide éprinomectine et le cestodicide praziquantel. L'efficacité insecticide de ce produit a été évaluée chez des chats infestés expérimentalement par C. lectularius dans une étude en aveugle et randomisée avec contrôle négatif. Deux groupes de 7 chats ont été formés, un groupe témoin non traité et un groupe traité par NexGard® Combo une fois au jour 0 à la dose indiquée sur l'étiquette. Les chats ont ensuite été testés chaque semaine, chacun avec vingt C. lectularius adultes non nourris, les jours 1, 7, 14, 21 et 28. Après un contact étroit avec la peau du chat pendant 15 minutes, les C. lectularius nourris et vivants ont été collectés et incubés pendant 96 heures. Les évaluations hebdomadaires d'efficacité ont été basées sur une comparaison du nombre de punaises de lit survivantes entre le groupe témoin et le groupe traité après 48, 72 et 96 heures d'incubation. Le modèle s'est avéré robuste car dans le groupe témoin, le taux d'alimentation moyen après 15 minutes de contact était de 94 % et 96 % des punaises de lit incubées étaient vivantes après 96 heures d'incubation. Des réductions significatives du nombre de punaises de lit vivantes ont été démontrées dans le groupe traité par Nexgard® Combo : après 96 heures d'incubation, les réductions variaient de 80,6 à 88,0 % pendant la période du jour 1 au jour 21 et ont chuté à 58 % au jour 28.

Geographical patterns and mechanisms of Cimex lectularius Linnaeus, 1758, and Cimex hemipterus Fabricius, 1803 (Hemiptera: Cimicidae) resistance to insecticides: a systematic review and meta-analysis.

This study aimed to review published scientific literature on bed bugs in countries where insecticide resistance has been reported worldwide from 2000 to 2021. Electronic databases, including Scopus, PubMed, and WOS, were searched. Out of 606 articles found in the initial search, we selected 57 articles, of which 40 articles had reported on Cimex lectularius (C. lectularius), and 22 papers had reported on Cimex hemipterus (C. hemipterus). Most studies on insecticide resistance were carried out on C. lectularius in North America (14, 35%) and C. hemipterus in Asia (16, 72.7%). The most common method used to detect bed bug resistance to insecticides was toxicological bioassay with an overall random pooled effect size of 0.38 (95% CI: 0.23-0.53) in C. lectularius and 0.46 (95% CI: 0.27-0.65) in C. hemipterus. Resistance to pyrethroids was reported against C. lectularius with an overall pooled effect size of 0.75 (95% CI: 0.56-0.94) and C. hemipterus with an overall pooled effect size of 0.81 (95% CI: 0.57-0.93) in 33.40 (82.5%) and 19.22 (86.3%) published articles, respectively. A very high resistance level to pyrethroids in both studied species was observed, and resistance ratios at the highest level were 76389.3 and 315.5 in C. lectularius and C. hemipterus, respectively. Resistance mechanisms against pyrethroids were reported from most locations except Iran and Thailand, but these mechanisms were not studied in other insecticide groups. These reports indicate that chemical control options for bed bugs are limited. Therefore, a combination of chemical and non-chemical strategies is recommended for bed bug control.

Seminal fluid and sperm diluent affect sperm metabolism in an insect: Evidence from NAD(P)H and flavin adenine dinucleotide autofluorescence lifetime imaging.

Sperm metabolism is fundamental to sperm motility and male fertility. Its measurement is still in its infancy, and recommendations do not exist as to whether or how to standardize laboratory procedures. Here, using the sperm of an insect, the common bedbug, Cimex lectularius, we demonstrate that standardization of sperm metabolism is required with respect to the artificial sperm storage medium and a natural medium, the seminal fluid. We used fluorescence lifetime imaging microscopy (FLIM) in combination with time-correlated single-photon counting (TCSPC) to quantify sperm metabolism based on the fluorescent properties of autofluorescent coenzymes, NAD(P)H and flavin adenine dinucleotide. Autofluorescence lifetimes (decay times) differ for the free and protein-bound state of the co-enzymes, and their relative contributions to the lifetime signal serve to characterize the metabolic state of cells. We found that artificial storage medium and seminal fluid separately, and additively, affected sperm metabolism. In a medium containing sugars and amino acids (Grace's Insect medium), sperm showed increased glycolysis compared with a commonly used storage medium, phosphate-buffered saline (PBS). Adding seminal fluid to the sperm additionally increased oxidative phosphorylation, likely reflecting increased energy production of sperm during activation. Our study provides a protocol to measure sperm metabolism independently from motility, stresses that protocol standardizations for sperm measurements should be implemented and, for the first time, demonstrates that seminal fluid alters sperm metabolism. Equivalent protocol standardizations should be imposed on metabolic investigations of human sperm samples.

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.

ATYPICAL LINEAR CONFIGURATION OF BEDBUG BITES IN AN EIGHT-YEAR-OLD BOY: A Case Report and Overview of Cimicosis.

At the beginning of the 21st century, the prevalence of Cimex species (bedbugs) infestation in human dwellings rose exponentially, particularly in the United States. Although there is no evidence that bedbugs transmit diseases to their hosts, they are difficult to eradicate, making them a source of psychological and physical distress and a socioeconomic burden to society. Here, the author describes the case of an eight-year-old boy who presented with widespread, multiple, itchy, red papules surrounded by round patches of erythematous, edematous skin, and was eventually diagnosed with cimicosis (bedbug infestation). Other family members living with the boy showed no clinical signs of bedbug infestation, and the bites on the boy were not in the typical three-row linear configuration associated with bedbug bites-which made this case compelling. Clinical diagnostic characteristics, symptom management, and suggestions on infestation eradication are provided. Biological and epidemiological characteristics of bedbug infestation are also described. Currently, evidence of simple, safe, and effective means of bedbug eradication is lacking.

An Earliest Endosymbiont, Wolbachia massiliensis sp. nov., Strain PL13 from the Bed Bug (Cimex hemipterus), Type Strain of a New Supergroup T.

The symbiotic Wolbachia are the most sophisticated mutualistic bacterium among all insect-associated microbiota. Wolbachia-insect relationship fluctuates from the simple facultative/parasitic to an obligate nutritional-mutualistic association as it was the case of the bedbug-Wolbachia from Cimexlectularius. Understanding this association may help in the control of associated arthropods. Genomic data have proven to be reliable tools in resolving some aspects of these symbiotic associations. Although, Wolbachia appear to be fastidious or uncultivated bacteria which strongly limited their study. Here we proposed Drosophila S2 cell line for the isolation and culture model to study Wolbachia strains. We therefore isolated and characterized a novel Wolbachia strain associated with the bedbug Cimexhemipterus, designated as wChem strain PL13, and proposed Wolbachiamassiliensis sp. nov. strain wChem-PL13 a type strain of this new species from new supergroup T. Phylogenetically, T-supergroup was close to F and S-supergroups from insects and D-supergroup from filarial nematodes. We determined the 1,291,339-bp genome of wChem-PL13, which was the smallest insect-associated Wolbachia genomes. Overall, the wChem genome shared 50% of protein coding genes with the other insect-associated facultative Wolbachia strains. These findings highlight the diversity of Wolbachia genotypes as well as the Wolbachia-host relationship among Cimicinae subfamily. The wChem provides folate and riboflavin vitamins on which the host depends, while the bacteria had a limited translation mechanism suggesting its strong dependence to its hosts. However, the clear-cut distinction between mutualism and parasitism of the wChem in C. hemipterus cannot be yet ruled out.

Knowledge, Experience, and Concerns Regarding Bed Bugs Among Emergency Medical Service Providers.

Introduction Bed bugs are commonly encountered by emergency medical service (EMS) providers. The objective of this study was to determine the frequency with which EMS providers encountered bed bugs, assess their knowledge about bed bugs, and analyze the actions they take after finding bed bugs. Methods We anonymously surveyed 407 EMS providers from 180 EMS agencies in northeast Ohio between September 1, 2018, through March 31, 2019. Results Among the providers surveyed, 21% (n = 84) of the EMS providers reported seeing bed bugs at least monthly, and 6% (n = 24) reported seeing bed bugs at least weekly. Being younger, male, and working in an urban environment (vs. rural) were associated with EMS providers reporting more frequent bed bug encounters (p: ≤.05). The mean level of concern for encountering bed bugs among EMS providers was 3.54 (SD: 1.15; scale: 1 = no concern, 5 = very concerned). Among the EMS providers who reported seeing bed bugs at least monthly, 30% took the affected EMS stretcher out of service when they encounter a bed bug, 43% took the EMS rig out of service, 83% cleaned the EMS stretcher with a disinfectant, and 88% notified the ED that their patient has bed bugs. EMS providers scored poorly (mean: 69% correct responses) in a seven-question assessment of basic bed bug biology and public health. Conclusion Based on our findings, we concluded that EMS knowledge and behavior related to bed bugs are suboptimal.

A Preliminary Report Showing Spinosad and Fluralaner Are Able to Incapacitate Cimex lectularius L., the Common Bed Bug.

Cimex lectularius L., the common bed bug, is a hematophagous human ectoparasite. The veterinary drugs, spinosad and fluralaner, were studied for their ability to incapacitate C. lectularius when administered in a blood meal using an artificial feeding system under laboratory conditions. Tested drug doses were based on the reported peak blood levels in animals given the drugs. Spinosad at doses 1,000 ng/mL or higher resulted in 75% or greater bed bug incapacitation (defined as death or immobility). Fluralaner at doses 500 ng/mL or higher had 100% bed bug incapacitation. Both drugs were significantly more effective than controls at these doses (P < 0.001).

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.

Susceptibility Status of Bedbugs (Hemiptera: Cimicidae) Against Pyrethroid and Organophosphate Insecticides in Dar es Salaam, Tanzania.

Cimex hemipterus resistance to residual insecticides is a growing public health concern worldwide. Herein, we report the susceptibility status of C. hemipterus against pyrethroid (permethrin) and organophosphate (dichlorvos) insecticides in Dar es Salaam. The knockdown efficacy of dichlorvos (99%) was greater than that of permethrin (43%), and mortality at the end of 24 h was also greater for dichlorvos than for permethrin. Mortality in recommended concentration of permethrin was lower than manufacturer's expectations. In contrast, similar concentrations in dichlorvos resulted into mortality of 100% at the end of 24 h. LC50 and LC95 values for permethrin were 3.36 (2.356-4.364) and 2,887.39 (2,886.37-2,888.39), respectively, whereas those of dichlorvos were 7.91 (3.85-11.97) and 44.39 (40.33-48.45). Dar es Salaam city has high coverage and usage of long-lasting insecticidal nets (LLINs) for prevent malaria. The resistance in bedbugs to permethrin may be related to the widespread use of the insecticide in LLINs. We recommend of the change from pyrethroids dichlorvos for the control of bedbugs.

The Benefit of a Single Oral Dose of Ivermectin in Humans: The Adverse Effects on Cimex lectularius L. Populations and Fecundity.

Objective To measure the population size and fecundity of the common bed bug Cimex lectularius L. (C. lectularius) after feeding it with the blood obtained from human subjects who have consumed a single dose of ivermectin. Methods  Serial blood samples were obtained from two human subjects at hour 0 (control) and 4-96 hours after they received a single 0.2 mg/kg dose of ivermectin. The blood samples were then fed to 2,273 bed bugs. Bed bug incapacitation rates, fecundity, and population sizes were recorded over a 54-day period. Whole blood ivermectin levels were measured in the human subjects and the insects. Results  The fold change in the size of the control group population over the course of the experiment was found to be 2.16. This was significantly greater (p: <.001) than for all the post-ivermectin feeding groups (range: -11.04-1.43). Two weeks after the experiment, the number of eggs laid per live adult female bed bug per day was 10.74 for controls, which was significantly different (p: <0.001) compared to all the post-ivermectin feeding groups (range: 0-4.28). Conclusions  There were significant reductions in C. lectularius population size and fecundity in insects that fed on blood obtained from human study subjects up to 96 hours after they have consumed a single oral dose of ivermectin.

Cimicosis in Persons Previously Fed Upon by Bed Bugs.

Introduction Bed bug infestations have risen dramatically in many industrialized nations in recent decades. Most people fed upon by bed bugs will develop a pruritic rash although the frequency with which this occurs is not definitively known and may depend on host factors including the duration of the infestation. Methods Surveys were completed from 706 emergency department (ED) patients in Cleveland, OH about their current and past exposure with bed bugs. Subjects were asked about any post-bed bug feeding rashes that developed. Results There were 24% (169/698) of subjects reporting either a current or past home bed bug infestation, with 37% (253/698) reporting they had previously been fed upon by a bed bug. Of those reporting a previous bed bug feeding, 68% (172/253) reported a pruritic post-bed bug feeding rash and 24% (57/237) reported developing a blister. Overall, 5% (37/705) of ED patients reported currently having a rash, but only 2% (14/698) of ED patients reported currently have bed bugs at home and of those, only 14% (2/14) said they currently had a rash. Conclusion While 68% of ED patients reported a pruritic post-bed bug feeding pruritic rash, almost a third of persons did not report developing the rash. Post-bed bug feeding blister reactions are less common. Asking ED patients about a rash had a low sensitivity of 14% (2-43%) and a specificity 95% (93-96%) to identify persons reporting home bed bugs.

Barriers of persistent long-lasting insecticidal nets utilization in villages around Lake Tana, Northwest Ethiopia: a qualitative study.

BACKGROUND: Malaria remains a major public health problem in Ethiopia. The use of LLINs is an effective approach to reducing transmission. Persistent use of LLINs is determined by numerous factors. Quantitative studies have assessed LLIN ownership and utilization, but the behavioral, socio-cultural, socioeconomic and net distribution contexts that impact their use have not been examined in depth. This study aimed to explore barriers of persistent LLIN use among communities around Lake Tana. METHODS: Twenty-three community residents who owned LLINs (15) or not (8) during the study period and 38 key informants were interviewed from April to June 2017. Phenomenological study was employed to explore the local contexts and factors that influence persistent use of LLINs. Individuals were purposefully selected to capture different views. Community residents were selected based on their permanent residence and LLIN use experience. Key informants were health extension workers, local leaders, students, and health professionals. The data were managed using QSR International NVivo Version 10 software and coded, and themes were identified. RESULTS: Killing ability of nets against arthropods other than mosquitoes reportedly made use of LLINs a favored malaria prevention method despite their ineffectiveness after 3 months. Conical nets were preferred due to their compatibility with varied sleeping structures. Numerous factors influenced persistent use, notably erroneous perceptions about LLINs, malaria and mosquitoes; bedbug infestation; inconvenience; unintended uses; distribution problem of nets; and socio-cultural and economic factors. Unintended uses were often associated with local needs and seldom linked with social issues and deficiencies in information about malaria and LLINs. Collateral benefits were considered important, principally in terms of disinfestation of bedbugs. CONCLUSIONS: Non-persistent LLIN use was associated with inconvenient bed net design and early damage; non-potency of the insecticide against other arthropods; facilitation of bedbug infestation; unintended uses; wrong perceptions about malaria, mosquitoes, and LLINs; and inadequate follow-up regarding LLINs utilization. Distribution of conical nets and provision of adequate information on LLINs and malaria may promote persistent use. Using an insecticide that also kills arthropods other than mosquitoes may reduce unintended uses and increase persistent use.

Risk Factors for Bed Bugs Among Urban Emergency Department Patients.

Bed bugs are a significant and under-studied public health nuisance. We surveyed 706 emergency department patients and found bed bug infestations were more likely (p < 0.05) among subjects having persons 19-64 years of age in the house, living in a group home, a previous history with bed bugs, and knowing someone who currently has bed bugs. Sleeping in a hotel, recent homelessness, obtaining used clothing or furniture and using a laundromat were not associated with increased risk (p > 0.05) for infestation. Individuals with less education and income were more likely (p < 0.05) to have bed bugs and express concern about getting bed bugs. Younger persons were more likely to correctly identify a picture of a bed bug compared to those over the age of 60 years (p < 0.001).

Bedbugs Evolved before Their Bat Hosts and Did Not Co-speciate with Ancient Humans.

All 100+ bedbug species (Cimicidae) are obligate blood-sucking parasites [1, 2]. In general, blood sucking (hematophagy) is thought to have evolved in generalist feeders adventitiously taking blood meals [3, 4], but those cimicid taxa currently considered ancestral are putative host specialists [1, 5]. Bats are believed to be the ancestral hosts of cimicids [1], but a cimicid fossil [6] predates the oldest known bat fossil [7] by >30 million years (Ma). The bedbugs that parasitize humans [1, 8] are host generalists, so their evolution from specialist ancestors is incompatible with the "resource efficiency" hypothesis and only partially consistent with the "oscillation" hypothesis [9-16]. Because quantifying host shift frequencies of hematophagous specialists and generalists may help to predict host associations when vertebrate ranges expand by climate change [17], livestock, and pet trade in general and because of the previously proposed role of human pre-history in parasite speciation [18-20], we constructed a fossil-dated, molecular phylogeny of the Cimicidae. This phylogeny places ancestral Cimicidae to 115 mya as hematophagous specialists with lineages that later frequently populated bat and bird lineages. We also found that the clades, including the two major current urban pests, Cimex lectularius and C. hemipterus, separated 47 mya, rejecting the notion that the evolutionary trajectories of Homo caused their divergence [18-21]. VIDEO ABSTRACT.

Evaluation of the Common Bed Bug, Cimex lectularius (Insecta: Hemiptera: Cimicidae) Susceptibility to λ-Cyhalothrin, Malathion, and Diazinon in Northeastern Iran.

The common bed bug, Cimex lectularius (Linnaeus 1758), is a nocturnal blood-sucking ectoparasite of humans that is highly prevalent in the northeast of Iran. In recent years, the efficacy of those insecticides that have been frequently used to control bed bugs in Iran has not been studied. Due to frequent complaints about bed bug treatment failures in Mashhad city (northeastern Iran), this study assessed the susceptibility of C. lectularius collected from a student residence hall to Diazinon, Malathion, and λ-cyhalothrin. The desired concentrations of each insecticide were prepared in acetone, and bioassays were performed using insecticide-impregnated filter paper method. The concentration-response data were subjected to POLO-PC software and data were analyzed by the log-probit procedure. The LC50 values of Diazinon and λ-cyhalothrin for examined bed bugs were 1,337.40 and 2,022.36 ppm, respectively. Malathion at the highest concentration (10,000 ppm) did not exhibit any toxicity to examined C. lectularius. Comparing these results to the same previous studies showed that susceptibility of examined bed bugs to these insecticides has been highly decreased. This study revealed an occurrence of insecticide resistance in bed bug populations in northeastern Iran. It also suggests that Malathion, Diazinon, and λ-cyhalothrin are ineffective against bed bugs in this region.

Description of a new bat-associated bug species of the Cimex lectularius group from Vietnam.

Cimex lectularius, the common bedbug is an important, emerging pest of both veterinary and medical importance. Here a recently discovered, genetically distinct new species of the C. lectularius group is described morphologically, as Cimex pulveratus Hornok sp. nov.

Antibody and cytokine levels in humans fed on by the common bedbug, Cimex lectularius L.

Little is known about cimicosis, the resultant dermal reaction from feeding activity by the common bedbug, Cimex lectularius L. We fed C. lectularius on human study subjects four times over four weeks and measured serum cytokine and antibody levels, and subjects recorded any cimicosis. The average time for subjects to develop cimicosis decreased with each feeding from 8.4, to 2.1, 1.5 and 1.3 days, respectively. There were no significant changes in total IgG, IgG1, IgG2, IgG4 or IgE levels between the first and fourth bedbug feedings, but there was a significant decrease in total IgG3 levels (P<.001). IgG4 was not required for cimicosis. Higher IgG2 and IgG4 levels at study visit 4 were associated with an increased duration of cimicosis (P=.04) and lower pruritis (P=.03), respectively. There were no significant changes in serum TNF-α, IL-1ß, IL-4, IL-5, IL-6, IL-10, IFN-γ and IL-17A levels before and one hour after the C. lectularius feeding. Lower post-C. lectularius feeding IL-6 levels were associated with increased pruritis (P=.001) and the time to maximum pruritis (P=.04), respectively. Higher post-C. lectularius feeding IL-5 levels were associated with a longer duration of pruritis (P=.05).

Ivermectin causes Cimex lectularius (bedbug) morbidity and mortality.

BACKGROUND: Bedbug infestations are increasing across North America and Europe, with more people presenting to Emergency Departments for treatment. Physicians cannot provide substantive treatment for people affected by bedbugs. STUDY OBJECTIVE: To determine if ivermectin, a relatively inexpensive and safe, long-acting oral anti-parasitic drug is able to cause bedbug morbidity and mortality. METHODS: We evaluated the effects of ivermectin on bedbugs using an artificial feeding membrane and mice and humans. Bedbug morbidity, mortality, and nymph molting was recorded. RESULTS: Using an artificial feeding membrane, bedbug mortality was 98% (n = 81) for 260 ng/mL ivermectin and 0% for 0 ng/mL ivermectin (control; n = 90) after 13 days. Mortality for bedbugs fed on mice injected with the human equivalent of 200 µg/kg ivermectin was 86% (n = 22), vs. 0% in the 0 µg/kg ivermectin (control; n = 21). Of the surviving nymphs, 0% exposed to ivermectin molted by day 75, vs. 80% in the control group by day 8. Bedbugs that fed once on human study subjects 3 h after consuming 200 µg/kg of oral ivermectin had a 63% (n = 24) 20-day mortality rate, vs. 8% (n = 24) in the control group. Of the surviving nymphs, 0% (n = 5) in the 3-h ivermectin group molted, vs. 80% (n = 10) of the control group. CONCLUSIONS: It may be possible that ivermectin could help eradicate, suppress, or prevent a bedbug infestation.