Resurgence of bedbugs in southern France: a local problem or the tip of the iceberg?

Activation of immune pathways in common bed bugs, Cimex lectularius, in response to bacterial immune challenges - a transcriptomics analysis

The common bed bug, Cimex lectularius, is an urban pest of global health significance, severely affecting the physical and mental health of humans. In contrast to most other blood-feeding arthropods, bed bugs are not major vectors of pathogens, but the underlying mechanisms for this phenomenon are largely unexplored. Here, we present the first transcriptomics study of bed bugs in response to immune challenges. To study transcriptional variations in bed bugs following ingestion of bacteria, we extracted and processed mRNA from body tissues of adult male bed bugs after ingestion of sterile blood or blood containing the Gram-positive (Gr+) bacterium Bacillus subtilis or the Gram-negative (Gr-) bacterium Escherichia coli. We analyzed mRNA from the bed bugs' midgut (the primary tissue involved in blood ingestion) and from the rest of their bodies (RoB; body minus head and midgut tissues). We show that the midgut exhibits a stronger immune response to ingestion of bacteria than the RoB, as indicated by the expression of genes encoding antimicrobial peptides (AMPs). Both the Toll and Imd signaling pathways, associated with immune responses, were highly activated by the ingestion of bacteria. Bacterial infection in bed bugs further provides evidence for metabolic reconfiguration and resource allocation in the bed bugs' midgut and RoB to promote production of AMPs. Our data suggest that infection with particular pathogens in bed bugs may be associated with altered metabolic pathways within the midgut and RoB that favors immune responses. We further show that multiple established cellular immune responses are preserved and are activated by the presence of specific pathogens. Our study provides a greater understanding of nuances in the immune responses of bed bugs towards pathogens that ultimately might contribute to novel bed bug control tactics.

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.

Resistance to Fipronil in the Common Bed Bug (Hemiptera: Cimicidae)

Cimex lectularius L. populations have been documented worldwide to be resistant to pyrethroids and neonicotinoids, insecticides that have been widely used to control bed bugs. There is an urgent need to discover new active ingredients with different modes of action to control bed bug populations. Fipronil, a phenylpyrazole that targets the GABA receptor, has been shown to be highly effective on bed bugs. However, because fipronil shares the same target site with dieldrin, we investigated the potential of fipronil resistance in bed bugs. Resistance ratios in eight North American populations and one European population ranged from 1.4- to >985-fold, with highly resistant populations on both continents. We evaluated metabolic resistance mechanisms mediated by cytochrome P450s, esterases, carboxylesterases, and glutathione S-transferases using synergists and a combination of synergists. All four detoxification enzyme classes play significant but variable roles in bed bug resistance to fipronil. Suppression of P450s and esterases with synergists eliminated resistance to fipronil in highly resistant bed bugs. Target-site insensitivity was evaluated by sequencing a fragment of the Rdl gene to detect the A302S mutation, known to confer resistance to dieldrin and fipronil in other species. All nine populations were homozygous for the wild-type genotype (susceptible phenotype). Highly resistant populations were also highly resistant to deltamethrin, suggesting that metabolic enzymes that are responsible for pyrethroid detoxification might also metabolize fipronil. It is imperative to understand the origins of fipronil resistance in the development or adoption of new active ingredients and implementation of integrated pest management programs.

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.

Population Genetic Structure and Breeding Pattern of Cimex hemipterus (F.) (Hemiptera: Cimicidae) in Malaysia

The surge in tropical bed bug Cimex hemipterus (Fabricius) (Hemiptera: Cimicidae) infestations has led to an increase in genomic studies. In this study, the population genetics and breeding patterns of 22 Malaysian populations were analyzed, including genetic differentiation and genetic distance. For seven microsatellite loci, the number of alleles varied from 6 to 14. The allelels per loci contrasted sharply between the overall population and within the populations. The average observed and expected heterozygosity was 0.280 and 0.828 for the overall population and 0.281 and 0.657 among the populations, respectively. Based on polymorphic information criteria, the markers with a value >0.5 were highly polymorphic. In the Hardy-Weinberg equilibrium, the loci of Ch 09ttn, Ch 01dn, and Ch 13dn of the overall population showed signs of a null allele. The stutter peaks caused no scoring errors; large allele dropouts were not detected for any loci; and a correlation imbalance was not indicated. The genetic differentiation among populations was moderate, with a coefficient of genetic differentiation (FST) of 0.144. The bed bug populations showed strong inbreeding, with highly positive coefficients of inbreeding (FIS). The molecular variation attributed to inbreeding was 83% within the populations, compared with 17% among the populations. The admixture individuals in STRUCTURE and neighbor-joining phylogenetic trees also indicated weak genetic structure in the geographical populations, suggesting moderate gene flows between populations. Thus, moderately active dispersion and human-mediated transport shaped the genetic structure of C. hemipterus populations in Malaysia.

Effect of Synergists on Deltamethrin Resistance in the Common Bed Bug (Hemiptera: Cimicidae)

The common bed bug, Cimex lectularius L. (Hemiptera: Cimicidae), is an obligate hematophagous insect that has resurged worldwide since the early 2000s. Bed bug control is largely based on the widespread, intensive application of pyrethroid-based insecticide formulations, resulting in the emergence of insecticide-resistant bed bug populations. Insecticide resistance is frequently linked to metabolic detoxification enzymes such as cytochrome monooxygenase (P450s), esterases, glutathione S-tranferase, and carboxylesterase. Therefore, one way to overcome insecticide resistance could be the formulation of insecticides with synergists that counteract metabolic resistance. To test this hypothesis, we evaluated the impact of four synergists-piperonyl butoxide (PBO), diethyl maleate (DEM), S,S,S-tributyl phosphorotrithioate (DEF), and triphenyl phosphate (TPP)-on deltamethrin efficacy in two pyrethroid-resistant bed bug strains. A statistically significant difference in synergism ratios (SR) of a highly resistant field-derived strain (Jersey City, resistance ratio [RR] = 20,000) was noted when any of the four synergists (PBO SR = 20.5; DEM SR = 11.7; DEF SR = 102.3; and TPP SR = 9.7) were used with deltamethrin. In a less deltamethrin-resistant strain, Cincinnati (RR = 3,333), pretreatment with PBO and DEM significantly synergized deltamethrin (PBO SR = 158.8; DEM = 58.8), whereas application of DEF and TPP had no synergistic effect. The synergism data collected strongly suggest that detoxification enzymes play a significant role in the metabolic mechanisms that mediate deltamethrin resistance in bed bugs. The development and use of safe metabolic synergists that suppress detoxification enzymes offers an interesting avenue for the management of insecticide-resistant field populations.

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.

Histamine as an emergent indoor contaminant: Accumulation and persistence in bed bug infested homes

Histamine is used in bronchial and dermal provocation, but it is rarely considered an environmental risk factor in allergic disease. Because bed bugs defecate large amounts of histamine as a component of their aggregation pheromone, we sought to determine if histamine accumulates in household dust in bed bug infested homes, and the effects of bed bug eradication with spatial heat on histamine levels in dust. We collected dust in homes and analyzed for histamine before, and up to three months after bed bug eradication. Histamine levels in bed bug infested homes were remarkably high (mean = 54.6±18.9 μg/100 mg of sieved household dust) and significantly higher than in control homes not infested with bed bugs (mean < 2.5±1.9 μg/100 mg of sieved household dust). Heat treatments that eradicated the bed bug infestations failed to reduce histamine levels, even three months after treatment. We report a clear association between histamine levels in household dust and bed bug infestations. The high concentrations, persistence, and proximity to humans during sleep suggest that bed bug-produced histamine may represent an emergent contaminant and pose a serious health risk in the indoor environment.

Effects of Cyclic Feeding and Starvation, Mating, and Sperm Condition on Egg Production and Fertility in the Common Bed Bug (Hemiptera: Cimicidae)

Bed bugs (Cimex lectularius L.) are now endemic in most major cities, but information regarding their basic biology is still largely based on research done over four decades ago. We investigated the effects of starvation, mating, sperm storage, and female and male age on egg production and hatch. Egg production cycles varied with the number of bloodmeals that females received. Once-mated females fed every 5 d had constant egg production for ∼75 d followed by a monotonic decline to near zero. Percentage egg hatch was high and constant, but declined after ∼30 d to near zero. To determine whether the age of the female, male, or sperm affected these patterns, we mated newly eclosed females to 60-d-old virgin males, 60-d-old mated males, or newly eclosed males. Females produced the most eggs when mated to young males, followed by old mated males, and then old virgin males; percentage hatch followed a similar pattern, suggesting that sperm stored within males for long was deficient. To examine effects of sperm stored within females, we mated newly eclosed females, starved them for 30 or 60 d, then fed them every 5 d. The 60-d starved group produced fewer eggs than the 30-d starved group, and both produced fewer eggs than young females mated to old or young males. Longer periods of sperm storage within females caused lower corresponding percentage hatch. These findings indicate egg production and hatch are governed by complex interactions among female and male age, frequency of feeding and mating, and sperm condition.

Insecticide resistance and resistance mechanisms in bed bugs, Cimex spp. (Hemiptera: Cimicidae)

The worldwide resurgence of bed bugs [both Cimex lectularius L. and Cimex hemipterus (F.)] over the past two decades is believed in large part to be due to the development of insecticide resistance. The transcriptomic and genomic studies since 2010, as well as morphological, biochemical and behavioral studies, have helped insecticide resistance research on bed bugs. Multiple resistance mechanisms, including penetration resistance through thickening or remodelling of the cuticle, metabolic resistance by increased activities of detoxification enzymes (e.g. cytochrome P450 monooxygenases and esterases), and knockdown resistance by kdr mutations, have been experimentally identified as conferring insecticide resistance in bed bugs. Other candidate resistance mechanisms, including behavioral resistance, some types of physiological resistance (e.g. increasing activities of esterases by point mutations, glutathione S-transferase, target site insensitivity including altered AChEs, GABA receptor insensitivity and altered nAChRs), symbiont-mediated resistance and other potential, yet undiscovered mechanisms may exist. This article reviews recent studies of resistance mechanisms and the genes governing insecticide resistance, potential candidate resistance mechanisms, and methods of monitoring insecticide resistance in bed bugs. This article provides an insight into the knowledge essential for the development of both insecticide resistance management (IRM) and integrated pest management (IPM) strategies for successful bed bug management.

Evaluation of the Potential for Secondary Kill for Ingested Insecticides in the Common Bed Bug (Hemiptera: Cimicidae)

Baits are a preferred method of urban pest management. Baits enable more targeted insecticide applications with a fraction of the active ingredient used in residual sprays. Bait translocation by foragers, and consequent secondary kill of nonforagers, enhances bait effectiveness in social insects, and in other group-living species like German cockroaches (Blattella germanica L.). We investigated the potential for secondary kill in bed bugs (Cimex lectularius L.), another gregarious species, using a liquid bait. We first investigated whether blood-fed adults enhance nymph survivorship within aggregations by increasing the local relative humidity (RH) and providing fecal nutrients. Higher RH (50% and 95%) resulted in greater survivorship of first instars compared with 0% RH. Therefore, in subsequent experiments, we controlled RH to decouple its effect on nymph survivorship from effects of fecal nutrients. The presence of fed or unfed adults did not increase unfed first instar survivorship, suggesting that if nymphs ingested feces, its nutritional benefits were minimal. Nymph survivorship was unaffected by the presence of adult males fed fipronil or clothianidin, suggesting that unlike in cockroaches, highly effective insecticides might not be effective as secondary kill toxicants in bed bugs. To directly compare secondary kill in first-instar bed bugs and B. germanica, we exposed both to insecticide-laden adult B. germanica feces. Whereas first-instar B. germanica died in the presence of insecticide-laden feces, bed bugs did not. We, therefore, conclude that secondary kill with neuroactive insecticides will likely not be a significant factor in bed bug population suppression.

Genetic Variability and Geographic Diversity of the Common Bed Bug (Hemiptera: Cimicidae) Populations from the Midwest Using Microsatellite Markers

With the recent global resurgence of the bed bugs (Cimex lectularius L.), there is a need to better understand its biology, ecology, and ability to establish populations. Bed bugs are domestic pests that feed mainly on mammalian blood. Although bed bugs have not been implicated as vectors of pathogens, their biting activity inflicts severe insomnia and allergic reactions. Moreover, they have recently developed resistance to various insecticides, which requires further molecular research to determine genetic variation and appropriate interventions. Population dynamics, including genetic differentiation and genetic distance of 10 populations from the Midwest were analyzed in this study. The bed bug samples collected by pest control companies were genotyped using eight species-specific microsatellite markers. Results showed all eight markers were polymorphic, with 8-16 alleles per locus, suggesting high genetic diversity. The FST values were >0.25, signifying pronounced genetic differentiation. The G-test results also indicated high genetic differentiation among populations. The frequency of the most common allele across all eight loci was 0.42. The coefficient of relatedness between each of the populations was >0.5, indicative of sibling or parent-offspring relationships, while the FIS and its confidence interval values were statistically insignificant within the populations tested. The populations departed from Hardy-Weinberg equilibrium, possibly because of high heterozygosity. The genetic distance analysis using a neighbor-joining tree showed that the populations from Kansas City, MO, were genetically separate from most of those from Nebraska, indicating a geographic pattern of genetic structure. Our study demonstrated the effectiveness of using microsatellite markers to study bed bugs population structure, thereby improving our understanding of bed bug population dynamics in the Midwest. Overall, this study showed a high genetic diversity and identified several new alleles in the bed bug populations in the Midwest.

Spatial genetic structure and restricted gene flow in bed bugs (Cimex lectularius) populations in France

Bed bugs (Cimex lectularius) are resurgent blood-sucking ectoparasites that are currently increasing at a rapid rate, particularly in industrialized countries, such as France. Despite the rapid spread of bed bugs, there is a lack of knowledge concerning the population structure and gene flow among C. lectularius populations in France. To fill this gap, a genetic study was conducted using 183 C. lectularius from 14 populations of bed bugs collected in a hotel and in individual apartments in the French Riviera and in the Saint Ouen suburb of Paris. The samples were genotyped using an isolated set of six polymorphic microsatellite loci, including five new loci which were newly isolated and chosen based on prior successful amplification, and one previously described loci (bb15b). The low genetic diversity observed in the samples (of one to five alleles) suggested that most of prospected populations were established by only a few individuals, possibly from a single mated female. The overall genetic differentiation was high and statistically significant (FST=0.556, p<0.0001). Pairwise analysis of the populations indicated significant genetic differentiation for 24 out of the 45 (53%) population pairs associated with FST, ranging from 0.0042 to 0.862. No obvious relationship between the level of genetic differentiation and the geographic distance was observed when considering all samples. Analysis with Structure software identified nine distinct genetic clusters within the dataset. These preliminary results help to elucidate the genetic structure and gene flow of C. lectularius populations in France; however, the available information should be expanded in further studies.

Competence of Cimex lectularius Bed Bugs for the Transmission of Bartonella quintana, the Agent of Trench Fever

Background

Bartonella quintana, the etiologic agent of trench fever and other human diseases, is transmitted by the feces of body lice. Recently, this bacterium has been detected in other arthropod families such as bed bugs, which begs the question of their involvement in B. quintana transmission. Although several infectious pathogens have been reported and are suggested to be transmitted by bed bugs, the evidence regarding their competence as vectors is unclear.

Methodology/Principal Findings

Bed bugs at the adult and instar developmental stages were fed three successive human blood meals inoculated with B. quintana bacterium from day one (D1) to D5; subsequently they were fed with pathogen-free human blood until the end of the experiment. Bed bugs and feces were collected in time series, to evaluate their capacities to acquire, multiply and expel viable B. quintana using molecular biology, immunohistochemistry and cultures assays. B. quintana was detected molecularly in 100% of randomly selected experimentally infected bed bug specimens (D3). The monitoring of B. quintana in bed bug feces showed that the bacterium was detectable starting on the 3^rd day post-infection (pi) and persisted until day 18±1 pi. Although immunohistochemistry assays localized the bacteria to the gastrointestinal bed bug gut, the detection of B. quintana in the first and second instar larva stages suggested a vertical non-transovarial transmission of the bacterium.

Conclusion

The present work demonstrated for the first time that bed bugs can acquire, maintain for more than 2 weeks and release viable B. quintana organisms following a stercorarial shedding. We also observed the vertical transmission of the bacterium to their progeny. Although the biological role of bed bugs in the transmission of B. quintana under natural conditions has yet to be confirmed, the present work highlights the need to reconsider monitoring of these arthropods for the transmission of human pathogens.

Bartonella quintana, the etiologic agent of trench fever and other human diseases, is known to be transmitted by the feces of body lice. Recently, the DNA of this bacterium has been detected in bed bugs. Several pathogens have been associated and suggested to be transmitted by bed bugs, despite the insufficient evidence to support this vector role. The aim of the present study was to assess the competence of bed bugs in the transmission of B. quintana using an experimental artificial model of infection. To this end, bed bugs were fed with human infected blood meals. On the 3^rd day post-infection (dpi) B. quintana was detected molecularly in 100% of experimentally infected bed bug. The bacterium was also detectable in bed bug feces starting on the 3^rd dpi and persisted until 18±1 dpi. Although immunohistochemistry assays localized the bacteria to the gastrointestinal bed bug gut, B. quintana was also detected in the first and second instars larva. The present work highlights the need to reconsider monitoring of bed bugs for the transmission of pathogens.

[The worldwide expansion of bed bugs also constitutes a problem in Germany]

Worldwide, reports of the spread of the bed bugs Cimex lectularius and C. hemipterus (in Australia) are increasing. Irrespective of hygiene conditions, the insects can be especially found in hotels and hostels as well as in other holiday accommodation, health facilities, transport and in the secondhand trade. From these localities the insects spread to private households. A bed bug infestation may well have health consequences and constitutes a heavy burden for those affected. The global spread of bed bugs appears to be multifactorially conditioned and the causes are controversially discussed. The spread could be explained, among other things, by the increase in international travel and trade in used goods. The limited availability of insecticides with long-term effects and the development of resistance to available agents could play a crucial role. In the absence of official data it is impossible to quantify the extent of the spread in Germany but pest controllers and public authorities report increasing numbers of cases and problems in control. As in other countries the latter appear to be caused among other things by the development of drug resistance (particularly pyrethroids). Against this background, prevention and thus the education of the public on the habits and dissemination routes of these insects remain crucial in order to counteract the spread of bed bugs.

Infestation by pyrethroids resistant bed bugs in the suburb of Paris, France

Bed bugs are hematophagous insects responsible for a re-emerging and challenging indoor pest in many countries. Bed bugs infestations may have health consequences including nuisance biting, cutaneous and systemic reactions. This resurgence can probably be attributed to factors such as increased international travel and development of resistance against insecticides. Resistance against pyrethroids has been reported several times from the USA and rarely in Europe. In France, very few data on bed bugs are available. The present study aimed to assess the infestation by bed bugs of a complex of two high-rise apartment buildings in the suburb of Paris and to evaluate their susceptibility to pyrethroid insecticides. We inspected for bed bugs 192 out of 198 apartments units (97%) and interviewed their residents. 76 (39.6%) apartments were infested. Among the 97 residents living in infested apartments, 53 (54.6%) reported bed bug bites. A total of 564 bed bugs were collected in the infested units. Bioassays showed that 54 out of 143 bed bugs were resistant to pyrethroids (37.8%; 95% confidence interval: 29.9-45.7%). DNA sequencing showed that all bed bugs tested (n = 124) had homozygous L925I kdr-like gene mutation. The level of pyrethroid resistance found indicates that this phenomenon was already established in the site and prompts the need to reevaluate the wide use of pyrethroids to control bed bugs.

Population variation in and selection for resistance to pyrethroid-neonicotinoid insecticides in the bed bug

Pyrethroid resistance in bed bugs, Cimex lectularius, has prompted a change to combination products that include a pyrethroid and a neonicotinoid. Ten populations of bed bugs were challenged with two combination products (Temprid SC and Transport GHP). Susceptibility of these populations varied, with the correlated response of the two products indicating cross resistance. We imposed selection on three populations using label rate Temprid, and then reared progeny from unselected and selected strains. All selected strains were significantly less susceptible to Temprid SC than unselected strains. Temprid selected strains were also less susceptible to Transport. The pyrethroid component of Temprid showed a significantly higher LD₅₀ in selected strains, but susceptibility to the neonicotinoid remained unchanged. Taken together these results indicate resistance to combination insecticides is present in field populations at levels that should be of concern, and that short-term selection affecting existing variance in susceptibility can quickly increase resistance.

Don't let the bedbugs bite: the Cimicidae debacle and the denial of healthcare and social justice

Although bedbug infestation is not a new public health problem, it is one that is becoming more alarming among healthcare professionals, public health officials, and ethicists given the magnitude of patients who may be denied treatment, or who are unable to access treatment, especially those underserved populations living in low income housing. Efforts to quarantine and eradicate Cimicidae have been and should be made, but such efforts require costly interventions. The alternative, however, can further exacerbate the already growing problems of injustice, i.e., unfair treatment of patients, inaccessibility of needed resources. In the following paper, I examine the ramifications of denying access to medical care, among other healthcare justice dilemmas surrounding bedbug infestations. I also explore the value of health, and how healthcare professionals and public officials often feel as though bedbugs are not a priority because they, themselves, are not diseases, regardless of the fact they cause physical and mental problems that affect a person's health. I propose recommendations for improving the health and well-being of those vulnerable populations who are facing a difficult and growing public health problem that is currently being ignored in medical and public health ethics literature, regardless of increased media attention and unusual habitats of localized infestations, e.g., Statue of Liberty, New York City.

Bed bugs reproductive life cycle in the clothes of a patient suffering from Alzheimer's disease results in iron deficiency anemia

We report the case of an 82-year-old patient, hospitalized for malaise. Her clothes were infested by numerous insects and the entomological analysis identified them as being Cimex lectularius (bed bugs). The history of the patient highlighted severe cognitive impairment. The biological assessment initially showed a profound microcytic, aregenerative, iron deficiency anemia. A vitamin B12 deficiency due to pernicious anemia (positive intrinsic factor antibodies) was also highlighted, but this was not enough to explain the anemia without macrocytosis. Laboratory tests, endoscopy and a CT scan eliminated a tumor etiology responsible for occult bleeding. The patient had a mild itchy rash which was linked to the massive colonization by the bed bugs. The C. lectularius bite is most often considered benign because it is not a vector of infectious agents. Far from trivial, a massive human colonization by bed bugs may cause such a hematic depletion that severe microcytic anemia may result.

Prevention, identification, and treatment options for the management of bed bug infestations

In the past decade, bed bug infestations have been increasing worldwide. Historically, studies have failed to provide evidence for the transmission of human diseases through bed bugs, but recent evidence is lacking. Although physical reactions to bed bug bites continue to be documented, evidence regarding the mental health effects arising from bed bug infestations is limited to anecdotes and case reports. This report provides an update and summary of the bed bug management strategies discussed during a workshop at the 2010 Canadian Public Health Association Conference. “Best practices” regarding prevention, identification, and treatment options are presented, using evidence from existing evaluative studies. Awareness of bed bug behaviour and proper building maintenance can prevent transfer of bed bugs from belongings, including second-hand items, and reduce entry points and harbourage sites. In addition to inspection by trained professionals, early recognition of clinical symptoms and environmental signs of an infestation are important to avoid further spread of bed bugs and to allow implementation of safe and effective treatment options. Early findings may indicate a need for special support for vulnerable individuals with mental health issues potentially exacerbated by bed bug infestations. Preparing units for treatment, including the removal of clutter, is essential. However, physical and financial limitations are challenges for managing bed bug infestations, especially for vulnerable populations. Current treatment options such as application of heat or pesticides can be effective when properly implemented, but there are concerns with pesticide resistance. An Integrated Pest Management approach is recommended and should include ongoing monitoring and prevention that are essential for positive treatment outcomes. Regulatory officials, building management, and pest management professionals are encouraged to collaborate using a systematic approach to address bed bug infestations.

Human travel and traveling bedbugs

BACKGROUND

A dramatic increase of reported bedbug (Cimex lectularius and Cimex hemipterus) infestations has been observed worldwide over the past decade. Bedbug infestations have also been detected across a wide range of travel accommodations, regardless of their comfort and hygiene levels. Travelers are increasingly exposed to the risks of bedbug bites, infestation of personal belongings, and subsequent contamination of newly visited accommodations and their homes.

METHODS

We searched Medline publications via the PubMed database. National bedbug recommendations, textbooks, newspapers, and Centers for Disease Control websites were also searched manually.

DISCUSSION

To detect infested sites, avoid or limit bedbug bites, and reduce the risk of contaminating one's belongings and home, bedbug biology and ecology must be understood. A detailed search of their most classic hiding niches is a key to finding adult bedbugs, nymphs, eggs, and feces or traces of blood from crushed bedbugs. Locally, bedbugs move by active displacement to feed (bite) during the night. Bed, mattress, sofa, and/or curtains are the most frequently infested places. If you find bedbugs, change your room or, even better, the hotel. Otherwise, travelers should follow recommendations for avoiding bedbugs and their bites during the night and apply certain simple rules to avoid infesting other sites or their home.

CONCLUSION

Travelers exposed to bedbugs can minimize the risks of bites and infestation of their belongings, and must also do their civic duty to avoid contributing to the subsequent contamination of other hotels and, finally, home.

The re-emergence of the bed bug as a nuisance pest: implications of resistance to the pyrethroid insecticides

A global resurgence of bed bugs (Hemiptera: Cimicidae) has led to renewed scientific interest in these insects. The current bed bug upsurge appears to have started almost synchronously in the late 1990 s in Europe, the U.S.A. and Australia. Several factors have led to this situation, with resistance to applied insecticides making a significant contribution. With a growing number of insecticides (DDT, carbamates, organophosphates etc.) being no longer available as a result of regulatory restrictions, the mainstay chemistry used for bed bug control over the past few decades has been the pyrethroid insecticides. With reports of increasing tolerance to pyrethroids leading to control failures on the rise, containing and eradicating bed bugs is proving to be a difficult task. Consequently, several recent studies have focused on determining the mode of action of pyrethroid resistance in bed bug populations sourced from different locations. Correct identification of the factor(s) responsible for the increasing resistance is critical to the development of effective management strategies, which need to be based, wherever possible, on firm scientific evidence. Here we review the literature on this topic, highlighting the mechanisms thought to be involved and the problems currently faced by pest control professionals in dealing with a developing pandemic.

Genetic analysis of bed bug populations reveals small propagule size within individual infestations but high genetic diversity across infestations from the eastern United States

Bed bugs (Cimex lectularius L.) are a resurgent pest worldwide and infestations within the United States are increasing at a rapid rate. Because of the physical and psychological discomfort inflicted by their blood feeding habits, and allergies and secondary infections associated with bites, bed bugs are recognized as a significant public health problem. Although bed bug infestations are spreading and becoming more prevalent, we have a poor understanding of their dispersal patterns and sources of infestation. To help fill this gap, we conducted a genetic study of 21 bed bug infestations from the eastern United States, nearly all of which came from single rooms within residences. We genotyped samples comprised of 8-10 individuals per infestation at nine polymorphic microsatellite loci. Despite high genetic diversity across all infestations, with 5-17 alleles per locus (mean = 10.3 alleles per locus), we found low genetic diversity (1-4 alleles per locus) within all but one of the infestations. These results suggest that nearly all the studied infestations were started by a small propagule possibly consisting of a singly mated female and/or her progeny, or a female mated with multiple males that were highly related to her. All infestations were strongly genetically differentiated from each other (mean pairwise F(ST) between populations = 0.68) and we did not find strong evidence of a geographic pattern of genetic structure, indicating infestations located in closer proximity to each other were nearly as genetically differentiated as those located hundreds of kilometers away. The high level of genetic diversity across infestations from the eastern United States together with the lack of geographically organized structure is consistent with multiple introductions into the United States from foreign sources.

Bed bugs: clinical relevance and control options

Since the late 1990s, bed bugs of the species Cimex lectularius and Cimex hemipterus have undergone a worldwide resurgence. These bed bugs are blood-sucking insects that readily bite humans. Cutaneous reactions may occur and can start out as small macular lesions that can develop into distinctive wheals of around 5 cm in diameter, which are accompanied by intense itching. Occasionally, bullous eruptions may result. If bed bugs are numerous, the patient can present with widespread urticaria or eythematous rashes. Often, bites occur in lines along the limbs. Over 40 pathogens have been detected in bed bugs, but there is no definitive evidence that they transmit any disease-causing organisms to humans. Anemia may result when bed bugs are numerous, and their allergens can trigger asthmatic reactions. The misuse of chemicals and other technologies for controlling bed bugs has the potential to have a deleterious impact on human health, while the insect itself can be the cause of significant psychological trauma. The control of bed bugs is challenging and should encompass a multidisciplinary approach utilizing nonchemical means of control and the judicious use of insecticides. For accommodation providers, risk management procedures should be implemented to reduce the potential of bed bug infestations.

Insect stings: clinical features and management

BACKGROUND

In human beings, local and systemic reactions can be caused both by blood-sucking insects and by venomous insect stings. In Central Europe, the insects that most commonly cause such reactions are honeybees, certain social wasps, mosquitoes, and flies.

METHODS

This article is based on a selective literature review, including guidelines from Germany and abroad.

RESULTS

Insect venom induces a toxic reaction at the site of the sting. Large local reactions are due to allergy and occur in up to 25% of the population; as many as 3.5% develop IgE-mediated, potentially life-threatening anaphylaxis, of which about 20 people die in Germany each year. Mastocytosis is found in 3% to 5% of patients with sting anaphylaxis, rendering these patients prone to very severe reactions. Blood-sucking by hematophagous insects can elicit a local allergic reaction, presenting as a wheal or papule, in at least 75% of the population. Large local reactions may ensue, but other diseases are rare. The acute symptoms of an insect sting are treated symptomatically. Patients who have had a systemic reaction or a large local reaction due to insect allergy must take permanent measures to avoid further allergen contact, and to make sure they can treat themselves adequately if stung again. Most patients with systemic anaphylactic reactions to bee or wasp stings need specific immunotherapy.

CONCLUSION

Insect stings can cause severe disease. Anaphylaxis due to bee or wasp stings is not a rare event; specific immunotherapy protects susceptible persons from further, potentially life-threatening reactions.