Bed bugs and possible transmission of human pathogens: a systematic review

The global population of bed bugs (Cimex lectularius and Cimex hemipterus, family Cimicidae) has undergone a significant resurgence since the late 1990s. This is likely due to an increase in global travel, trade, and the number of insecticide-resistant bed bugs. The global bed bug population is estimated to be increasing by 100-500 % annually. The worldwide spread of bed bugs is concerning, because they are a significant socioeconomic burden and a major concern to public health. According to the United States Environmental Protection Agency, bed bugs are "a pest of significant health importance." Additionally, 68 % of U.S. pest professionals reported that bed bugs are the most challenging pest to treat. Upwards of 45 disease pathogens have been reported in bed bugs. Recent studies report that bed bugs may be competent vectors for pathogens, such as Bartonella quintana and Trypanosoma cruzi. However, public health reports have thus far failed to produce evidence that major infectious disease outbreaks have been associated with bed bugs. Since many disease pathogens have previously been reported in bed bugs and the worldwide bed bug population is now drastically increasing, it stands to reason to wonder if bed bugs might transmit human pathogens. This review includes a literature search on recently published clinical and laboratory studies (1990-2016) investigating bed bugs as potential vectors of infectious disease, and reports the significant findings and limitations of the reviewed studies. To date, no published study has demonstrated a causal relationship between bed bugs and infectious disease transmission in humans. Also, we present and propose to expand on previous hypotheses as to why bed bugs do not transmit human pathogens. Bed bugs may contain "neutralizing factors" that attenuate pathogen virulence and, thereby, decrease the ability of bed bugs to transmit infectious disease.

The mental health impact of bed bug infestations: a scoping review

OBJECTIVES

We conducted a scoping review to identify and summarize the current state of knowledge regarding the mental health effects associated with bed bugs.

METHODS

We employed a five-stage scoping review framework, to systematically identify and review eligible articles. Eligibility criteria included a focus on bed bug infestations and reference to mental health impacts. Descriptive information was then extracted from each article, including the specific mental health effects cited.

RESULTS

An initial search yielded 920 unique articles on the topic of bed bugs. Of these, 261 underwent abstract review, and 167 underwent full-text review. Full-text review and subsequent review of reference lists yielded a final sample of 51 articles. Numerous mental health effects were linked to bed bug infestations, including severe psychiatric symptoms. However, the majority (n = 31) of the articles were commentary papers; only five original research articles were identified.

CONCLUSIONS

Although significant mental health effects are often linked to bed bugs, such discussions remain largely anecdotal. Despite recognition that the impact of bed bugs constitutes an important public health concern, little empirical evidence currently exists on this topic.

Pharmacokinetics of fluralaner as a systemic drug to control infestations of the common bed bug, Cimex lectularius, in poultry facilities

BACKGROUND

Bed bug infestations are re-emerging in the poultry industry throughout the USA. Although the impacts of bed bugs on birds' health and welfare are poorly understood, adverse outcomes are expected, including stress, anemia, infections and lower production rates. Worker welfare is also an important consideration in commercial poultry farms. A limited number of insecticides are available for use in the complex spatial environment of commercial farms. Systemic drugs have the potential to overcome the limitations of existing pest management tactics. A recent study showed that fluralaner administered to chickens caused high levels of mortality in bed bugs.

METHODS

To further understand the efficacy of this approach, we evaluated the pharmacokinetics of an oral solid formulation of fluralaner in 11 chickens and quantified its plasma concentration in chickens using UPLC/MS. We administered fluralaner to chickens with two doses of Bravecto® (each 0.5 mg/kg body mass) via gavage 1 week apart and evaluated its efficacy on bed bugs that fed on medicated chickens for up to 28 days post-treatment.

RESULTS

Bed bugs that fed on fluralaner-treated chickens experienced > 50% mortality within 30 min of the administration of Bravecto and 100% mortality 2 days post-treatment. Mortality slowly declined to 66.6% by day 28. Fluralaner was quantifiable in the hens' plasma for at least 28 days post-treatment. The treatment resulted in maximal plasma concentrations (Cmax) of 106.4 ng/ml around day 9.0 (Tmax), substantially higher than the LC90, the concentration needed to kill 90% of the bed bugs.

CONCLUSIONS

Fluralaner appears to be a promising candidate for bed bug control in poultry farms, with a treatment effect lasting at least 28 days.

Pilot study: specific immunotherapy in patients with Papular urticaria by Cimex lectularius

Summary

Background. Papular urticaria is a chronic allergic reaction induced by insect bites. In México the most common causative arthropods reported are bed bugs, fleas and mosquitoes. Approximately 70% of people who are bitten by Cimex lectularius experience hypersensitive reactions, papular urticaria, extensive erythema, urticaria, and even anaphylaxis has been reported, Pruritus is the major complaint, impairing quality of life and sleep. Immunotherapy has been used in mosquito bite papular urticaria resulting in improvement of skin lesions and possibly protecting against reactions to subsequent exposures to mosquitoes. Methods. Children, 4-10 years of age, with recurrent papular urticaria due to bedbugs not responsive to multiple treatments were included. An initial allergy assessment included clinical history, skin prick test (SPT), and specific IgE sensitisation was performed to confirmed bedbug sensitization. Twenty children were randomized to receive subcutaneous specific immunotherapy (SSI) with whole body bed bug extract or conventional treatment. The treatment was carried out over twelve months and the response was assessed using the Dermatology Quality of Life Index (DLQ), the immunotherapy satisfaction questionnaire (ESPIA questionnaire) and the 12-Item Pruritus Severity Scale (12-IPSS). The results from both the treated and control groups were compared. Results. The twenty patients were randomized, 12 to receive immunotherapy and 8 to receive conventional treatment for 12 months. Quality of life improved with a reduction in the DLQI score of 19.83 in the immunotherapy group versus 9 in the conventional treatment group (p=.03). Itch improved with a reduction in the 12-IPSS of 16.5 in the immunotherapy group versus 9.63 in the conventional treatment group (p=0.02). After twelve months of treatment, all 12 patients who received immunotherapy, reported a decrease of persistent cutaneous lesions but the 8 on conventional treatment did not. A mean score of 95.75 (SD 3.3) was recorded for satisfaction with immunotherapy. Conclusions. Patients with papular urticaria by Cimex lectularius receiving allergen immunotherapy for 1 year showed a significant improvement compared with baseline and patients receiving conventional treatment regarding skin lesions, quality of life impairment, intensity of pruritus and satisfaction with immunotherapy.

A novel prolixicin identified in common bed bugs with activity against both bacteria and parasites

The hematophagous common bed bug, Cimex lectularius, is not known to transmit human pathogens outside laboratory settings, having evolved various immune defense mechanisms including the expression of antimicrobial peptides (AMPs). We unveil three novel prolixicin AMPs in bed bugs, exhibiting strong homology to the prolixicin of kissing bugs, Rhodnius prolixus, and to diptericin/attacin AMPs. We demonstrate for the first time sex-specific and immune mode-specific upregulation of these prolixicins in immune organs, the midgut and rest of body, following injection and ingestion of Gr+ (Bacillus subtilis) and Gr- (Escherichia coli) bacteria. Synthetic CL-prolixicin2 significantly inhibited growth of E. coli strains and killed or impeded Trypanosoma cruzi, the Chagas disease agent. Our findings suggest that prolixicins are regulated by both IMD and Toll immune pathways, supporting cross-talk and blurred functional differentiation between major immune pathways. The efficacy of CL-prolixicin2 against T. cruzi underscores the potential of AMPs in Chagas disease management.

Efficiency of MALDI-TOF MS at identifying and discriminating immature stages of cimex lectularius and cimex hemipterus bed bugs

Over the last two decades, an increase in bed bug infestations has been observed worldwide. Although their definitive role as vectors of infectious agents has not yet been demonstrated, bed bugs have a direct effect on human health through dermatological reactions to their bites and psychological disorders linked to domestic infestations. In this study, the effectiveness of using MALDI-TOF MS to correctly identify these two bed bug species at immature stages was assessed, as well as it effectiveness as discriminating between the immature stages (IS) of C. lectularius and C. hemipterus and their associated developmental stages. A total of 305 specimens were subjected to MALDI-TOF MS analysis, including 153 C. lectularius (28 eggs and 25 nymphs per stage from IS1 to IS5) and 152 C. hemipterus (27 eggs and 25 nymphs per stage from IS1 to IS5). ). MALDI-TOF MS analysis enabled us to obtain 84.97% (130/153) of high-quality MS spectra in terms of reproducibility and profile intensity. Twenty-four spectra including two per stage, from egg to IS5, and per bed bug species - were added to our in-house MS reference arthropod spectra database. All specimens were correctly identified at the species level, independently of the developmental stage, with log score values (LSVs) ranging from 1.75 to 2.79 (mean = 2.29 ± 0.12) and 1.81 to 2.71 (mean = 2.37 ± 0.03) for C. lectularius and C. hemipterus, respectively. MALDI-TOF MS correctly classified 53,33% (104/195) of the Cimex at the correct immature stage. Conversely, an accurate comparison of the profiles with a Genetic Algorithm model underlined that grouping the immature stages in two groups, early (IS1-IS2) and late (IS3-IS4-IS5), made it possible to obtain a cross validation (CV) and recognition capability (RC) greater than 92% and 94%, respectively, for both species. This study holds great promise for the management of bed bug infestations.

First official report of bed bug (Hemiptera, Cimicidae) infestations in Algeria

Background

Bed bugs are hematophagous insects with a long history of presence in human communities. Over the last three decades, infestations by bed bugs in human dwellings have drastically increased, leading to a rise in bed bug concerns. Nevertheless, very little is known about the bed bug species and their population diversity in Algeria.

Method

A pilot entomological inventory was performed in May 2019 in Tizi Ouzou, in northern Algeria. The gathered bed bug specimens were identified by morphological and molecular approaches, followed by neighbor-joining and network phylogenetic analyses.

Results

A total of seven out of 12 requested locations were allowed to inspect for bed bug infestation. Of these, three locations were found with active bed bug infestations. A total of 145 specimens belonging to different life stages [egg (21), nymph (74), adult male (17), and female (33)] were collected and analyzed using morphological and molecular approaches. The adult specimens were identified as Cimex lectularius according to specific morphological criteria, most importantly the pronotum laterally expanded with more flattened extreme margins. Morphological identification of the adults was confirmed further by conventional PCR targeting 450 bp fragment of the COI gene. All the nymphs and eggs were also molecularly identified as C. lectularius. Neighbor-Joining phylogenetic tree reconstructed with the collected specimens provides clues on the presence of two closely phylogenetic groups. The first one gathers our samples of Algeria with previously reported COI haplotype sequences from Asian, European, and North American countries. The second group encompasses a lesser-documented haplotype reported in Europe and Central America. These findings were further confirmed by network analysis.

Conclusions

These results provide evidence of established C. lectularius infestation in Algeria and its potential dispersal capacity by travelers or immigrants and will help future management of these ectoparasites.

Optimization and establishment of laboratory rearing conditions for Cimex lectularius L. against variable temperature and relative humidity

Emerging infestations of bed bugs are affecting normal human lifestyle globally. This study has been designed to optimize the rearing conditions for Cimex lectularius L. (Hemiptera), to support the scientific research on them. Bed bugs have been projected onto three different temperature (20 °C, 25 °C, and 30 °C) and relative humidity (50%, 70%, and 90%) conditions to check their overall growth and survival rate. Adult mortality, weight loss, egg laying, percentage hatching, hatching initiation and completion, nymph mortality, and molting have been evaluated to optimize the best conditions. The temperature at 25 °C with 90% RH showed minimum mortality for adults (female 13.33 ± 3.33% and male 6.67 ± 3.33%) and nymphs (13.33 ± 3.33%), while maximum egg laying (40.33 ± 1.86), with highest percentage hatching (98.23 ± 0.58%). At 30 °C with 90% RH, hatching initiation and completion (5.19 ± 0.12 days and 7.23 ± 0.16 days) as well as molting initiation and completion (3.73 ± 0.12 days and 7.00 ± 0.24 days) were found to be fastest. Thus, it can be concluded that 25 °C with 90% RH is ideal for rearing of adults and 30 °C with 90% RH is appropriate for rapid growth of nymphs.

Bed bug control with various dusts: Efficacy comparison between silicon dioxide, diatomaceous earth, and Sommières earth

Bed bugs are considered a major public health problem in industrialized countries. Usually, bed bug infestations are managed using a combination of physical and chemical methods. In recent years, new strategies for bed bug control have emerged, particularly the use of dusts like diatomaceous earth and silicon dioxide. However, in Europe, the use of silicon dioxide is restricted to professional, while diatomaceous earth can be harmful to the lungs. This study aimed to assess bed bug mortality rates associated with Sommières earth, green clay, talc, and sodium bicarbonate compared to silicon dioxide and diatomaceous earth from a pest management company, diatomaceous earth for litter conditioner, and diatomaceous earth from a supermarket. We tested permanent exposure, short exposure, horizontal transfer and repellent effect on two bed bug colonies. Sommières earth demonstrated efficacy ranging from 75% to 100% in permanent and short exposures, similar to the efficacy of diatomaceous earth from the pest management company. On the contrary, diatomaceous earth for litter conditioner and diatomaceous earth from a supermarket, green clay, talc, and sodium bicarbonate were found to be ineffective. This study demonstrates, for the first time, the efficacy of Sommières earth against bed bugs, but also highlights the variability in efficacy of diatomaceous earths on bed bugs depending on their quality.

Protocol for tropical bed bug use as forensic tools

As blood-feeding insects that feed on human hosts, bed bugs could be used in forensic investigations if they are present at a crime scene with no apparent evidence. This study describes how tropical bed bugs (Cimex hemipterus) can be used as forensic tools to collect valid human DNA samples. Short Tandem Repeat (STR) analysis was performed on collected bed bug samples, whereby the results indicate that the obtained quantities of human DNA are mostly substantial to facilitate a comprehensive genetic profiling process.

Morphometric Characteristics and Species Identification of Bed Bugs (Hemiptera: Cimicidae) in Eastern Iran

Background

The common bed bugs, Cimex lectularius, and tropical bed bugs, Cimex hemipterus are the primary species of public health importance in the family Cimicidae. This study aimed to determine the morphometric criteria and prevalent species of bed bugs in eastern Iran.

Methods

Bed bugs were collected from March 2021 to June 2022 from infested residential buildings and apartments in eastern Iran, including North Khorasan, Khorasan Razavi, and Sistan and Baluchistan Provinces. The morphological and morphometrical characteristics were used to identify collected bed bugs at inter- and intra-specific levels.

Results

A total of 34 isolates comprising 127 adult bed bugs were collected from Bojnord, Mashhad, Neishabur, Taibad, Sabzevar, Kashmer, Zahedan, Saravan, Rask, Pishin and Chabahar. Of these, 33 isolates (n=124) were found to be tropical bed bugs, C. hemipterus, and one population (n=3) was identified as C. lectularius. The index pronotal width/length ratio was calculated from 2.72 to 2.94 and 1.98 to 2.47 for C. lectularius and C. hemipterus, respectively. The length/width ratio of the hind femur was 3.365 in C. hemipterus and 4.267 in C. lectularius. The ratio of length/width of the third femur (F3 l/w) between populations of C. hemipterus was different, and this difference was statistically significant (P< 0.05).

Conclusion

The results of this study indicated that C. hemipterus was the dominant bed bug species in the east of Iran and provided more morphometric criteria of C. hemipterus for researchers to identify the species and determine the intraspecific variations in the present and future.

Molecular genotyping of pyrethroid resistant mutations and their haplotypes in bed bug populations from Greece

The resurgence of bed bugs poses significant risks to public health and tourism-driven economies in Southern Europe, including Greece. Control efforts largely rely on pyrethroids; however, the widespread selection of knockdown resistance (kdr) mutations has compromised their effectiveness. Molecular monitoring is therefore essential for accurate species identification and resistance surveillance to support evidence-based pest management strategies. In this study, we analyzed bed bug populations collected from Athens, Thessaloniki, and Heraklion between 2021 and 2024. Species identification was performed via DNA barcoding of the cytochrome oxidase I (COI) gene, while kdr mutations in the voltage-gated sodium channel (VGSC) gene-specifically V419L, L925I, and I936F-were assessed to determine their frequencies and haplotype distributions. All specimens were identified as Cimex lectularius. The L925I mutation reached fixation (100%) in Thessaloniki and Heraklion, while V419L was detected at frequencies of 30.00% and 50.00%, respectively; I936F was not detected in these populations. In Athens, L925I was highly prevalent (98.40%), while V419L (5.27%) and I936F (0.60%) were detected at lower frequencies. Haplotype analysis revealed Haplotype B (L925I only) as the most common in Athens (91.20%) and Thessaloniki (60.0%), while Haplotype C (L925I + V419L) predominated in Heraklion (76.92%). Additional haplotypes were identified in Athens, including Haplotype Bb (L925I + I936F), marking its first detection in Europe. These findings highlight the widespread presence of kdr mutations and underscore the urgent need for integrated pest management (IPM) strategies, incorporating resistance monitoring, alternative insecticides, and non-chemical control methods to mitigate the growing challenge of pyrethroid resistance in bed bugs.

Morphological, molecular, and MALDI-TOF MS identification of bed bugs and associated Wolbachia species from Cameroon

After vanishing from the public eye for more than 50 years, bed bugs have resurged to become one of the most widely discussed and heavily researched insect pests in the world. This study presents the basic information of infestations of tropical bed bugs, Cimex hemipterus (Hemiptera: Cimicidae), in Cameroon. A total of 248 immature stage and adult bed bug specimens were collected from households and a travel agency in Yaoundé and Douala, Cameroon. The ability of MALDI-TOF MS to identify bed bugs was tested using heads for adults and cephalothoraxes for immature stages. Microorganism screening was performed by qPCR and confirmed by regular PCR and sequencing. Based on morphometrical criteria, four stages of immature bed bugs are represented. Of the 248 bed bug specimens morphologically identified as Cimex hemipterus, 246 (77 males, 65 females and 104 immature specimens) were submitted to MALDI-TOF MS analysis. Of the 222 adults and immature specimens tested, 122 (59.9 %) produced good quality MALDI-TOF MS spectra (35 adults and 87 immature specimens). Blind testing allowed species level identification of 98.21 % of adult and immature C. hemipterus. Among the bacteria tested, only Wolbachia DNA was found in 12/246 (4.8 %) bed bugs. More surveys in the country are warranted to assess the true level of bed bug infestations, in order to take appropriate action for their control.