Assessment of Conventional Insecticides against Common Bed Bugs Cimex Hemipterus (Hemiptera: Cimicidae) in Jeddah Province, Saudi Arabia

Bed bugs, Cimex hemipterus (Hemiptera: Cimicidae) are small insects that are considered public health pests and cause many health and economic problems. The efficacy of Organophosphorus insecticides (Safrotin and Actikill) and pyrethroids (Project and Cyper Safe) in controlling C. hemipterus adults and nymphs were investigated using contact and dipping methods. The WHO protocol was followed for insecticides application. The results of the current study showed that the project pesticide from the pyrethroids group gave the highest effectiveness against bed bugs, as the value of the concentration that killed 50% (LC50) of insects was of the adults (264.8, 337.5 ppm) when using dipping and contact methods, respectively. while the LC50 value when applying the two methods of the same insecticide against nymphs was 254.7 and 329.3ppm, respectively. However, Safrotin the more effective organophosphorus insecticide. The dipping method was more effective than the contact method for all insecticides, and the nymphs were more susceptible than the adults (LC50= 1502.6 and 1065.28ppm). The pesticides can be arranged in descending order according to their effect as follows: Project> Cyper Safe > Safrotin > Actikill. Our findings suggest that bed bugs in Jeddah Province may have developed resistance to common pesticides used in public health pest management programs. For this reason, this study recommends a periodic evaluation of the effectiveness of pesticides to be used during emergency pest outbreaks

High levels of pyrethroid resistance and super-kdr mutations in the populations of tropical bed bug, Cimex hemipterus, in Iran

Background The tropical bed bug, Cimex hemipterus, is an important ectoparasite causing various health problems. This species is mainly confined to tropical regions; however, insecticide resistance, global warming, and globalization have changed its distribution map. Molecular information on pyrethroid resistance, which is essential for the development of control programs, is unknown for C. hemipterus in expanded areas. The present study was designed to determine the permethrin resistance status, characterize the pyrethroid receptor sites in voltage-gated sodium channel (vgsc) gene, and identify the resistance-related mutations in the populations of tropical bed bug in Iran. Methods Live bed bugs were collected, and adults of C. hemipterus were selected for bioassay and molecular surveys. Bioassay was performed by tarsal contact with permethrin 0.75% in mixed-sex of samples. Conventional and quantitative TaqMan and SYBR Green real-time PCR assays were conducted to characterize the vgsc gene and genotypes of studied populations. Results In the bioassay tests, the mortality rates were in the range of 30.7–38.7% and 56.2–77.4% in 24 and 48 h, respectively. The knockdown rates of studied populations were in the range of 32.2–46.6% and 61.5–83.8% in the first and second days, respectively. The KT50 and KT90 values in the Cimex lectularius Kh1 strain were presented as 5.39 and 15.55 h, respectively. These values in the selected populations of C. hemipterus varied from 27.9 to 29.5 and from 82.8 to 104.4 h, respectively. Knockdown time ratios (KR50 and KR90) in these populations varied from 5.17 to 6.17-fold compared with those of the C. lectularius Kh1 strain. Fragments of vgsc gene with 355 bp and 812 bp were amplified. Analysis of sequences revealed the A468T substitution, kdr-associated D953G, and super-kdr M918I and L1014F mutations in all populations. Conclusions The specific/sensitive, safe, and rapid diagnostic assays developed in this study are recommended for detection of kdr/super-kdr mutations and frequency of mutant alleles. The presence of super-kdr mutations and high resistance to permethrin in all the populations necessitate the reconsideration of control approaches against C. hemipterus. Graphical Abstract

Bed Bugs (Hemiptera: Cimicidae) Population Diversity and First Record of Cimex hemipterus in Paris

Cimex lectularius and C. hemipterus are blood-sucking insects with a long history of presence in human communities. We investigated the molecular diversity of the bed bug population of Paris and its suburb cities using cytochrome oxidase 1 (CO1) sequencing. A total of 1211 specimens belonging to different life stages were collected from 62 infested human dwellings in Paris (13 out of 20 arrondissements) and the surrounding cities (18 cities). Morphological determination and COI sequencing of 132 specimens demonstrated C. lectularius as the predominant species and, surprisingly, the presence of C. hemipterus in four infested areas of Paris and its suburb cities. Neighbor-joining tree and network analyses depicted the presence of two C. lectularius populations. Most samples from Paris and its suburb cities clustered in a major clade. The second population encompasses specimens from Paris (arrondissements 11 and 19) and its suburb cities (e.g., Bobigny, Pantin, and Montreuil) that clustered with Hungary, Czechia, and Finland. This is the second evidence for C. hemipterus infestation in France and the third in Europe, which challenges the classic pattern of C. hemipterus dispersion and implies sympatric occurrence of C. lectularius and C. hemipterus. Since Paris is one of the most popular tourist destinations in the world, our observations shed light on bed bugs’ dispersal dynamic and may help future vector control strategies.

Fecundity, Survival and Susceptibility of Bedbugs (Cimex Hemipterus), Exposed to Selected Classes of Insecticides: A Short Report

Background: Tropical bed bug, Cimex hemipterus, is a nocturnal obligate blood-sucking ecto-parasite of humans that is highly prevalent in Nigeria. Bed bug control heavily relies on the application of several insecticides-based formulations. Insecticide resistance in bed bug populations has been widely reported. Here, we assessed the mortality and fecundity of bed bugs following exposure to different classes of insecticides. Methods: Bed bugs were collected from students’ halls of resident and exposed to DDT (4%), permethrin (0.75), bendiocarb (0.1) and malathion (4%) insecticide-impregnated papers. Mortality and number of eggs laid by each exposed groups were recorded at 24hrs, 48hrs and 72hrs. Results: The relative numbers of eggs produced by bedbugs in the DDT, bendiocarb and malathion assays were lower than what was observed in the control 24 hours after exposure. The highest reduction in egg production was observed in the malathion exposed-group compared to the other insecticides and the control group. The impact of the different assays on bugs mortality revealed DDT to produce a time-dependent outcome with the highest death rate (36.7%) recorded 24 hours’ post-exposure. In contrast, malathion and bendiocarb impacted the most mortality (53.3% and 46.6%) after 72 hours. Conclusion: This study revealed an occurrence of suspected insecticide resistance to all classes of insecticide used in bed bug populations in Lagos State, Nigeria.

Characterization of bacterial communities associated with blood-fed and starved tropical bed bugs, Cimex hemipterus (F.) (Hemiptera): a high throughput metabarcoding analysis

With the development of new metagenomic techniques, the microbial community structure of common bed bugs, Cimex lectularius, is well-studied, while information regarding the constituents of the bacterial communities associated with tropical bed bugs, Cimex hemipterus, is lacking. In this study, the bacteria communities in the blood-fed and starved tropical bed bugs were analysed and characterized by amplifying the v3-v4 hypervariable region of the 16S rRNA gene region, followed by MiSeq Illumina sequencing. Across all samples, Proteobacteria made up more than 99% of the microbial community. An alpha-proteobacterium Wolbachia and gamma-proteobacterium, including Dickeya chrysanthemi and Pseudomonas, were the dominant OTUs at the genus level. Although the dominant OTUs of bacterial communities of blood-fed and starved bed bugs were the same, bacterial genera present in lower numbers were varied. The bacteria load in starved bed bugs was also higher than blood-fed bed bugs.

Assessment of Tropical Bed Bug (Hemiptera: Cimicidae), Infestations in Cape Coast, Ghana: Household Control Practices and Efficacy of Commercial Insecticides and Long-Lasting Insecticidal Nets Against Field Bed Bugs

This study reports the first baseline information on tropical bed bug, Cimex hemipterus (F.) (Hemiptera: Cimicidae), infestations in Ghana. The purpose of this study was to assess bed bug infestation levels, and the efficacy of locally available insecticides and long-lasting insecticidal nets (LLINs) in controlling field bed bugs populations in the Cape Coast region. A survey was undertaken to assess bed bug infestation levels and current control practices by residents. In total, 205 bed bug affected households were identified in 20 communities and live bed bug infestations were associated with most of these premises. Many homeowners knew of other households (from 1 to 3) with a bed bug infestation. Residents reported itching and swelling of the skin from the bed bug bites and the bites were considered severe. The most common household bed bug control strategy was the application of insecticides. However, LLINs and commercially formulated insecticides commonly used by households (notably chloropyrifos and pyrethroid-based formulations) did not efficaciously suppress field collected strains of C. hemipterus. Using a dipping bioassay, mean mortality ranged from 0 to 60% for eggs, nymphs, and adults, and less than 40% mortality was observed in bed bugs placed on insecticide-treated filter paper. Each LLINs (all are pyrethroid based) produced a mean mortality of less than 20% in adult bed bugs. For a more effective response to the global bed bug resurgence in developing countries, government and supporting agencies need to render assistance to bed bug affected residents through the provision of improved pest management strategies.

High Levels of Pyrethroid Resistance and Super-Kdr Mutations in the Populations of Tropical Bed Bug, Cimex Hemipterus, in Iran

Background: Tropical bed bug, Cimex hemipterus, is an important ectoparasite causing various health problems. This species is mainly confined to tropical regions; however, insecticide resistance, global warming, and globalization have changed its distribution map. Molecular information on pyrethroid resistance, which is essential for the development of control programs, is unknown for C. hemipterus in expanded areas. The present study was designed to determine the permethrin resistance status, characterize the pyrethroid receptor sites in voltage-gated sodium channel (vgsc) gene and identify the resistance-related mutations in the populations of tropical bed bug in Iran. Methods: Live bed bugs were collected, and adults of C. hemipterus were selected for bioassay and molecular surveys. Bioassay was performed by tarsal contact with permethrin 0.75% in mixed-sex of samples. Conventional and quantitative TaqMan and SYBR green real-time PCR assays were conducted to characterize the vgsc gene and genotypes of studied populations. Results: In the bioassay tests, the mortality rates were in the range of 30.7-38.7% and 56.2-77.4% in 24 and 48 hrs, respectively. The knockdown rates of studied populations were in the range of 32.2-46.6% and 61.5-83.8% in the first and second days, respectively. The KT50 and KT90 values in the C. lectularius Kh1 strain were presented as 5.39 and 15.55 hrs, respectively. These values in the selected populations of C. hemipterus varied from 27.9 to 29.5 and from 82.8 to 104.4 hrs, respectively. Knockdown resistance ratios (KR50 and KR90) in these populations varied from 5.17 to 6.17-fold compared with those of the C. lectularius Kh1 strain. Fragments of vgsc gene with 355 bp and 812 bp were amplified. Analysis of sequences revealed the A468T substitution, kdr-associated D953G, and super-kdr M918I and L1014F mutations in all populations. Conclusions: The simple, specific/sensitive and rapid diagnostic assays developed in this study are recommended for detection of kdr/super-kdr mutations and frequency of mutant alleles. The presence of super-kdr mutations and high resistance to permethrin in all the populations necessitate the reconsideration of control approaches against C. hemipterus.

Detection of the Tropical Bed Bug Cimex hemipterus (Fabricius, 1803) in Belgorod (Russia)

The tropical bed bug Cimex hemipterus (Fabricius, 1803) was reliably detected in Belgorod in 2020 for the first time. Specimens were collected in dormitories for foreign students at both Belgorod State National Research University and Belgorod State Technological University named after V.G. Shukhov. Retrospective analyses of specimens collected in earlier years reveal that Cimex hemipterus was already present in Belgorod in 2013, and subsequently ousted the cosmopolitan species Cimex lectularius Linnaeus, 1758 which inhabited the area earlier. AcknowledgementsThe author is grateful to professor V.B. Golub (Voronezh State University) for valuable advice and assistance in species identification, professor S.P. Gaponov (Voronezh State University) for help in preparing this manuscript, as well as to everyone who helped in material collecting.