Epidemiological analysis of pediculosis and the distribution of kdr mutation frequency in head lice populations in Torbat Heydarieh city of Khorasan Razavi Province, Northeastern Iran.

Head lice infestations are the most prominent ectoparasitic infection in the world, including Iran, particularly among school children. Recently, numerous cases of infestation have been reported in various provinces of the country. This study aimed to investigate the prevalence of head louse infestations and analyze kdr gene sequences in terms of resistance mutations in the Torbat-e Heydarieh, Mahvelat, and Zaveh cities of Khorasan Razavi Province, Northeast Iran. The data related to the epidemiological and demographic history of head lice populations were extracted from their medical records and analyzed in Excel software. After extracting the genomic DNA, the kdr fragment was amplified using specific primers. The sequences were also analyzed using bioinformatics software. The prevalence of head louse infestations was 1.59% and 1.7% during 2016 and 2017, respectively. Sequence analysis revealed the frequency distribution of two kdr haplotypes, I and V, in the study areas. The increase in head louse infestations in recent years and the simultaneous presence of kdr mutations indicate the need for new treatments and monitoring/controlling resistance to head louse insecticides.

Usefulness of the superior orbitomeatal line without the lens included in the scan range at different tube voltage during pediatric head CT.

INTRODUCTION AND OBJECTIVES: To compare the real time skin dosimeter values at lens between with the lens included in the scan range (orbitomeatal base line [OML]) or without the lens included in the scan range (superior orbitomeatal line [SOML]) at different tube voltages. MATERIALS AND METHODS: We used three pediatric anthropomorphic phantoms with a 64 detector-row computed tomography (CT) scanner with the OML- or SOML-protocol at different tube voltages during the head CT. A real time skin dosimeter was inserted into the phantom center of the head, and surfaces of the lens. We compared the real time skin dosimeter values at lens between the OML- and SOML-protocol. RESULTS: There were no significant differences in the real time skin dosimeter values for the head in the scan area for each phantom at different tube voltages between the OML- and SOML-protocol (p > 0.05 for all phantom). Compared with the OML protocol, it is possible to reduce the real time skin dosimeter values at lens by approximately 80% by using the SOML protocol (p < 0.05) at all tube voltages. Compared with the OML protocol, it is possible to reduce the real time skin dosimeter values at mammary gland by approximately 20% by using the SOML protocol (p < 0.05) at all tube voltages. CONCLUSIONS: During the pediatric head CT examination, SOML protocol was possible to reduce the real time skin dosimeter values at lens by approximately 80% compared with OML protocol at all tube voltages.

The association between knockdown resistance and treatment outcome of 1% permethrin lotion in head lice infestations in Nonthaburi province, Thailand.

Head lice infestations significantly impact schoolchildren, with permethrin being the primary treatment. The escalation in the prevalence of the knockdown resistance (kdr) mutation, potentially affecting treatment efficacy, is highly concerning. This study examined head lice infestation prevalence, the efficacy of 1% permethrin lotion, kdr mutation frequency, and the association between kdr genotype and permethrin treatment outcomes in schoolchildren in Nonthaburi province, Thailand. Participants and lice samples were collected from six primary schools using cluster sampling. Clinical outcomes and adverse events were assessed on days 7 and 14 post-treatment. Kdr mutations (T917I) in head lice samples were analyzed using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Head lice infestation prevalence was 6.1%, with a kdr mutation frequency of 63.2% and a permethrin cure rate of approximately 50%. Multivariate regression analysis revealed the association between kdr genotype and clinical response to permethrin treatment (Odds Ratio (OR) = 13.15, p = 0.005). The presence of resistance genes hinders the cure rate (presence 35.9% versus absence 85.7%). These findings highlight the importance of the kdr genotype in predicting permethrin treatment responses in head lice infestations. Furthermore, in regions with documented reduced permethrin efficacy and a high prevalence of kdr mutations, alternative non-pyrethroid-based pediculicides should be considered. This research could help improve the control of head lice infestations, especially in problematic areas of Thailand.

Quantitative structure-insecticidal activity of essential oils on the human head louse (Pediculus humanus capitis).

In the search for natural and non-toxic products alternatives to synthetic pesticides, the fumigant and repellent activities of 35 essential oils are predicted in the human head louse (Pediculus humanus capitis) through the Quantitative Structure-Activity Relationships (QSAR) theory. The number of constituents of essential oils with weight percentage composition greater than 1% varies from 1 to 15, encompassing up to 213 structurally diverse compounds in the entire dataset. The 27,976 structural descriptors used to characterizing these complex mixtures are calculated as linear combinations of non-conformational descriptors for the components. This approach is considered simple enough to evaluate the effects that changes in the composition of each component could have on the studied bioactivities. The best linear regression models found, obtained through the Replacement Method variable subset selection method, are applied to predict 13 essential oils from a previous study with unknown property data. The results show that the simple methodology applied here could be useful for predicting properties of interest in complex mixtures such as essential oils.

Remote refocusing for multi-scale imaging.

Significance: The technique of remote focusing (RF) has attracted considerable attention among microscopists due to its ability to quickly adjust focus across different planes, thus facilitating quicker volumetric imaging. However, the difficulty in changing objectives to align with a matching objective in a remote setting while upholding key requirements remains a challenge. Aim: We aim to propose a customized yet straightforward technique to align multiple objectives with a remote objective, employing an identical set of optical elements to ensure meeting the criteria of remote focusing. Approach: We propose a simple optical approach for aligning multiple objectives with a singular remote objective to achieve a perfect imaging system. This method utilizes readily accessible, commercial optical components to meet the fundamental requirements of remote focusing. Results: Our experimental observations indicate that the proposed RF technique offers at least comparable, if not superior, performance over a significant axial depth compared with the conventional RF technique based on commercial lenses while offering the flexibility to switch the objective for multi-scale imaging. Conclusions: The proposed technique addresses various microscopy challenges, particularly in the realm of multi-resolution imaging. We have experimentally demonstrated the efficacy of this technique by capturing images of focal volumes generated by two distinct objectives in a water medium.

Applications of Lightsheet Fluorescence Microscopy by High Numerical Aperture Detection Lens.

This Review explores the evolution, improvements, and recent applications of Light Sheet Fluorescence Microscopy (LSFM) in biological research using a high numerical aperture detection objective (lens) for imaging subcellular structures. The Review begins with an overview of the development of LSFM, tracing its evolution from its inception to its current state and emphasizing key milestones and technological advancements over the years. Subsequently, we will discuss various improvements of LSFM techniques, covering advancements in hardware such as illumination strategies, optical designs, and sample preparation methods that have enhanced imaging capabilities and resolution. The advancements in data acquisition and processing are also included, which provides a brief overview of the recent development of artificial intelligence. Fluorescence probes that were commonly used in LSFM will be highlighted, together with some insights regarding the selection of potential probe candidates for future LSFM development. Furthermore, we also discuss recent advances in the application of LSFM with a focus on high numerical aperture detection objectives for various biological studies. For sample preparation techniques, there are discussions regarding fluorescence probe selection, tissue clearing protocols, and some insights into expansion microscopy. Integrated setups such as adaptive optics, single objective modification, and microfluidics will also be some of the key discussion points in this Review. We hope that this comprehensive Review will provide a holistic perspective on the historical development, technical enhancements, and cutting-edge applications of LSFM, showcasing its pivotal role and future potential in advancing biological research.

Prevalence and associated factors of head lice infestation among primary school children in low- and middle-income countries: systematic review and meta-analysis.

INTRODUCTION: Head lice infestation remains a persistent public health concern among primary school children in resource-limited settings, affecting their well-being and academic performance. Despite previous studies, there is no consistent evidence on the prevalence and factors associated with head lice infestation. This study aimed to determine the prevalence and factors related to head lice infestation among primary school children in low and middle-income countries. METHODS: This review was conducted by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. Relevant electronic databases, including PubMed, Cochrane Library, Web of Science, Science Direct, AJOL, and Google Scholar, were used to retrieve articles. The study included only published articles written in English languages between December 01, 2014 to January 31, 2024 for studies reporting the prevalence of head lice infestation or associated factors among primary school children in low- and middle-income countries. This review has been registered on PROSPERO with Prospero registration number CRD42024506959. The heterogeneity of the data was evaluated using the I2 statistic. A meta-analysis was conducted using STATA 17 software, with a 95% confidence interval. Publication bias was evaluated using funnel plots and statistical tests, such as Egger's and Beggs's tests, to identify publication biases in the included studies. Meta-regression was also carried out to assess the source of publication of publication bias. RESULTS: The review included 39 studies involving 105,383 primary school children. The pooled prevalence of head lice infestation among primary school children in low- and middle-income countries was 19.96% (95% CI; 13.97, 25.95). This review also found out that being a girl was 3.71 times (AOR = 3.71; 95% CI: 1.22-11.26) more likely to have head lice infestation as compared to boys, while children with a previous history of infestation were 4.51 times (AOR = 4.51; 95% CI: 2.31-8.83) more likely to have head lice infestation as compared to their counterparts. CONCLUSION: The overall prevalence of head lice infestation among primary school children in low- and middle-income countries was found to be high. Female gender, children who had a previous history of infestation, and family size were significant predictors of head lice infestation. As a result, policymakers and program administrators should focus on the identified determinants.

Exploring the lived experiences of adolescent girls affected by head lice infestation: a qualitative descriptive study.

BACKGROUND: Head lice infestation is a prevalent dermatological condition among adolescent girls, which has wide-ranging adverse physical, psychological, and emotional effects on their lives. However, these experiences have been sparsely documented. This study aimed to investigate the lived experiences of Iranian adolescent girls regarding head lice infestation. METHODS: In this phenomenological study, a purposive sampling technique was employed to select 15 adolescent girls who were experiencing head lice infestation. Collaboration was established with local schools to identify and recruit the participants. Subsequently, the purpose and nature of the study were explained to the identified participants and their guardians. Semi-structured in-depth interviews were conducted to gather the necessary data. The collected data underwent analysis using Colaizzi's seven-step method. To enhance the credibility of the findings, Lincoln and Guba's (2004) criteria were applied. The management of the data was facilitated through the utilization of MAXQDA software version 0.9.5. RESULTS: The average age of the participants, aged 12 to 17, was 14.5 (standard deviation = 1.7). In terms of education, the majority of them had completed upper secondary education (n = 8, 53.3%), followed by lower secondary education (n = 4, 26.6%). The participants' experiences were categorized into four main themes and 15 sub-themes. The main themes included living in the shadow of fear, torment of infestation, "struggling with head lice, and disturbing ramifications. The sub-themes encompassed social fear, fear of harm, fear of beauty decline, stigma, bullying behavior, self-blame, adversity, challenging struggle, effective coping, nonconforming behavior, family disruption, academic disruption, health threats, and confused mental state. CONCLUSION: During head lice infestation, adolescent girls endured negative experiences and extensive fears, considering it a significant ordeal. They encountered multiple challenges while dealing with lice and utilized both adaptive and maladaptive strategies to cope with the infestation. It is recommended to enhance public awareness regarding head lice infestation, and healthcare providers should offer emotional support and counseling services to affected girls and their families.

Flexible solid immersion meniscus lens (SIMlens) approach for enhancing biological imaging of cleared samples.

Tissue-clearing techniques have revolutionized the field of biological imaging by rendering biological specimens transparent and enabling inside optical detection. Light-sheet fluorescence microscopy (LSFM) is a powerful tool for three-dimensional imaging of large biological samples. Combining tissue-clearing techniques with LSFM has advanced the efficient 3D visualization of these samples. A crucial challenge with LSFM is the requirement for the objective to operate within the clearing reagent, which can cause aberrations. To address this issue, we introduce a novel, to our knowledge, approach for the flexible design of the solid immersion refractive meniscus lens (SIMlens), facilitating the use of air objectives with cleared samples. Compared to the previous SIMlens, this method not only eliminates aberrations but also offers customized options for enhancing the numerical aperture and working distance of the objective lens, achieving at least a 10% improvement. We have demonstrated the feasibility of this new method using mouse brain samples.

Bartonella quintana detection among arthropods and their hosts: a systematic review and meta-analysis.

BACKGROUND: Bartonella quintana is a body louse-borne bacterium causing bacteremia and infective endocarditis. We aimed to describe B. quintana detection among arthropods and their hosts. METHODS: We searched databases in PubMed Central/MEDLINE, Scopus, Embase, and Web of Science from January 1, 1915 (the year of B. quintana discovery) to January 1, 2024, to identify publications containing specific search terms relating to B. quintana detection among arthropods. Descriptive statistics and meta-analysis of pooled prevalence using random-effects models were performed for all arthropods and body and head lice. RESULTS: Of 1265 records, 62 articles were included, describing 8839 body lice, 4962 head lice, and 1692 other arthropods, such as different species of fleas, bedbugs, mites, and ticks. Arthropods were collected from 37 countries, of which 28 had arthropods with B. quintana DNA. Among articles that reported B. quintana detection among individual arthropods, 1445 of 14,088 (0.1026, 95% CI [0.0976; 0.1077]) arthropods tested positive for B. quintana DNA, generating a random-effects model global prevalence of 0.0666 (95% CI [0.0426; 0.1026]). Fifty-six studies tested 8839 body lice, of which 1679 had B. quintana DNA (0.1899, 95% CI [0.1818; 0.1983]), generating a random-effects model pooled prevalence of 0.2312 (95% CI [0.1784; 0.2843]). Forty-two studies tested 4962 head lice, of which 390 head lice from 20 studies originating from 11 different countries had B. quintana DNA (0.0786, 95% CI [0.0713; 0.0864]). Eight studies detected B. quintana DNA exclusively on head lice. Five studies reported greater B. quintana detection on head lice than body lice; all originated from low-resource environments. CONCLUSIONS: Bartonella quintana is a vector-borne bacterium with a global distribution, disproportionately affecting marginalized populations. Bartonella quintana DNA has been detected in many different arthropod species, though not all of these arthropods meet criteria to be considered vectors for B. quintana transmission. Body lice have long been known to transmit B. quintana. A limited number of studies suggest that head lice may also act as possible vectors for B. quintana in specific low-resource contexts.

Identification and Spatiotemporal Expression of a Putative New GABA Receptor Subunit in the Human Body Louse Pediculus humanus humanus.

The human louse (Pediculus humanus) is an obligatory blood feeding ectoparasite with two ecotypes: the human body louse (Pediculus humanus humanus), a competent vector of several bacterial pathogens, and the human head louse (Pediculus humanus capitis), responsible for pediculosis and affecting millions of people around the globe. GABA (γ-aminobutyric acid) receptors, members of the cys-loop ligand gated ion channel superfamily, are among the main pharmacological targets for insecticides. In insects, there are four subunits of GABA receptors: resistant-to-dieldrin (RDL), glycin-like receptor of drosophila (GRD), ligand-gated chloride channel homologue3 (LCCH3), and 8916 are well described and form distinct phylogenetic clades revealing orthologous relationships. Our previous studies in the human body louse confirmed that subunits Phh-RDL, Phh-GRD, and Phh-LCCH3 are well clustered in their corresponding clades. In the present work, we cloned and characterized a putative new GABA receptor subunit in the human body louse that we named HoCas, for Homologous to Cys-loop α like subunit. Extending our analysis to arthropods, HoCas was found to be conserved and clustered in a new (fifth) phylogenetic clade. Interestingly, the gene encoding this subunit is ancestral and has been lost in some insect orders. Compared to the other studied GABA receptor subunits, HoCas exhibited a relatively higher expression level in all development stages and in different tissues of human body louse. These findings improved our understanding of the complex nature of GABA receptors in Pediculus humanus and more generally in arthropods.

Toxicity of 6-gingerol and Cymbopogon citratus against Pediculus humanus capitis De Geer (Phthiraptera: Pediculidae): Mortality, detoxifying enzymes, and morphological ultrastructure alterations in lice.

Pediculus humanus capitis (head louse), which causes pediculosis capitis, remains a global health concern. Plant products are efficient alternative pediculicides for treating the human ectoparasite P. h. capitis which is resistant to permethrin. The study evaluates the toxicity and mechanisms of 6-gingerol and Cymbopogon citratus leaf extract on P. h. capitis. Pediculus humanus capitis adult stages were exposed to three different dosages of 6-gingerol and C. citratus crude leaf extract on filter sheets for 5, 10, and 30 min, respectively. The biochemical approach was used to assess the activity of detoxifying enzymes including acetylcholinesterase (AChE), glutathione S-transferase (GST), and oxidase. Scanning electron microscope (SEM) was used to investigate the ultrastructure of the morphological body of lice. After 30 min, 6-gingerol and C. citratus leaf extract killed P. h. capitis completely. Bioassay periods significantly affected lice mortality (P < 0.05). The LC50 values for 6-gingerol and C. citratus extract were 1.79 µg/cm2 and 25.0 µg/cm2, respectively. 6-Gingerol and C. citratus leaf extract significantly lower AChE and GST activity (P < 0.05). Cymbopogon citratus also caused morphological ultrastructure changes in P. h. capitis, including an irregularly formed head, thorax, abdominal respiratory spiracles, and belly. 6-Gingerol and C. citratus leaf extracts could be used as an alternate pediculicide to decrease P. h. capitis populations.

Effects of magnification on restorative dental preparation performance: a scoping review and level of evidence mapping.

OBJECTIVE: This scoping review aimed to identify and describe the available evidence on the effect of magnifying devices (loupe or microscope) on the performance of restorative dental preparations. MATERIALS AND METHODS: This study was conducted according to the PRISMA-ScR guidelines for scoping reviews and registered on the INPLASY database. An electronic search was performed in four databases and Grey literature for articles published until November 2023. Eligibility criteria were determined using the PICOS strategy and comprised studies that evaluated the performance of magnification devices for restorative dental preparations. A bibliographic mapping of the evidence was conducted. RESULTS: Sixteen studies met the inclusion criteria. Most of the studies (n = 12) compared the performance of dental preparations using magnification loupes vs. no magnification. The magnification for loupes and microscopes ranged from 2.5x to 4.0x and 6.4x to 10x, respectively. The use of magnifying loupes improved the performance of restorative preparations in 66.6% of the evaluated studies. However, when the magnifications were compared, the greater magnification provided by microscopes did not improve preparation performance compared to magnification loupes. Regarding the place of publication, the American continent concentrates the most significant number of evidence. CONCLUSIONS: Although evidence for magnification improving the performance of dental preparations has increased over the last decade, basically only in vitro studies (most of which have taken place in the Americas) have been reported in the literature. The evidence suggests that magnification significantly improves restorative preparation performance when compared to non-magnification. However, higher magnifications (e.g., microscopes) do not appear to improve tooth preparation performance compared with lower magnification devices (e.g., magnification loupes). CLINICAL RELEVANCE: Available evidence supports that using magnification can improve the performance of restored tooth preparations. However, high magnifications have no advantages over lower magnifications.

Extended depth-of-field wide-field fluorescence microscopy with a micro-mirror array lens system for versatile cellular examination.

We present a versatile extended depth-of-field (EDOF) wide-field fluorescence microscopy using a new, to the best of our knowledge, active device, micro-mirror array lens system (MALS) for calibration-free and orientation-insensitive EDOF imaging. The MALS changed the focal plane during image acquisition, and the system could be operated in any orientation. Two EDOF imaging modes of high-speed accumulation and low-speed surface sectioning were implemented. The performance was demonstrated in non-contact imaging of conjunctival goblet cells in live mice and depth-resolved cellular examination of ex-vivo human cancer specimens. MALS-based EDOF microscopy has potential for versatile cellular examination.

Upconversion nanoparticles doped optical lens: let's see the near-infrared light.

The human cannot detect light with a wavelength exceeding 700 nm, primarily due to limitations in the physiological structure of the human eye. However, in certain specific scenarios, the ability to detect near-infrared (NIR) light proves to be extremely valuable. To attain this desired capability, NIR up conversion nanoparticles (UCNPs) were prepared and doped in the optical lens materials, aiming to obtain a NIR light "visible" optical lens. It is demonstrated that the doping of UCNPs in the optical lens materials does not significantly impact on their mechanical properties, optical properties, surface properties and it exhibits excellent biocompatibility in cell and animal experiments. More importantly, the UCNPs doping can convert NIR light into visible light within the material effectively and stably. The eyes can "see" the NIR light after wearing such UCNPs doped optical lens. Such NIR light visible optical lens could have great potential in actual applications.

Body Louse Pathogen Surveillance among Persons Experiencing Homelessness, Canada, 2020-2021.

We analyzed body lice collected from persons experiencing homelessness in Winnipeg, Manitoba, Canada, during 2020-2021 to confirm vector species and ecotype and to identify louseborne pathogens. Of 556 lice analyzed from 7 persons, 17 louse pools (218 lice) from 1 person were positive for the louseborne bacterium Bartonella quintana.