Head Lice Research Articles

Morphological discrimination of human lice (Anoplura: Pediculidae) by eggs’ cap-like operculum

Human lice have long been parasites of humans and are responsible for several epidemics in human medical history. However, their morphology, particularly head and body lice, remains very similar. In this study, we discriminate human louse species based on the number, shape and size of aeropyles (respiratory pores) of the egg operculum as well as the size of the respiratory orifice in the aeropyles. For this purpose, lice and eggs were collected from infested patients referring to Parasitology Department of Avicenne Hospital (Bobigny, France) and analyzed morphologically. The microscopic examination of the aeropyles revealed a large variation in the number ranging from 5 to 12 for head lice, 10 to 16 for body lice and 13 to 18 for pubic lice with a statistically distinct average of 8.3, 12.9 and 15.7, respectively. Although the length of the head and body louse eggs were almost similar, the width of body louse eggs were bigger than those of head louse (412.9 μm and 363.5 μm, respectively), while pubic louse eggs had the smallest length (692.9 μm) and width (286.1 μm). In addition, pubic louse eggs had a greater operculum length and width (253.7 μm length and 220.7 μm width) than head (230.6 μm length and 210.2 μm width) and body lice (227.9 μm length and 199.9 μm width). Moreover, pubic lice had the smallest average aeropyle size (41.2 μm) compared to head (51.1 μm) and body lice (49.1 μm). The respiratory orifice on the aeropyles of head and body lice (9.9 μm) were almost twice as big as those of pubic lice (4.9 μm). There was an inverse correlation between the number of aeropyles and their size in head, body and pubic lice. These findings are helpful in accurate identification of human louse species using their eggs, which could be useful for control management strategies against these ectoparasites.

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.

Systematic review of the evidence for treatment and management of common skin conditions in resource-limited settings: An update.

The skin is the largest and most visible organ of the human body. As such, skin infections can have a significant impact on overall health, social wellbeing and self-image. In 2019, we published a systematic review of the treatment, prevention and public health control of skin infections including impetigo, scabies, crusted scabies and tinea in resource-limited settings where skin infections are endemic. This current review serves as an update to assess the evidence for treatment of these conditions as well as atopic dermatitis, molluscum contagiosum and head lice in endemic settings. The data from this systematic review have supported an update to the Australian National Healthy Skin guidelines. A systematic review was conducted using two separate searches in MEDLINE, PubMed, Embase, CINAHL, Cochrane and Web of Science. The first search was an update of the 2018 systematic review using the same search strategy for the same skin conditions to identify emerging literature from 2018 to 2022. The second search strategy used the same key terms but with the addition of atopic dermatitis, head lice and molluscum contagiosum from 1960 to 2022. Eligible studies included Indigenous peoples and populations in resource-limited settings with a diagnosis of impetigo, scabies, crusted scabies, tinea capitis, atopic dermatitis, molluscum contagiosum or who presented with head lice. Studies conducted in high-income countries were excluded. Articles were screened for inclusion independently by one author with a second group of reviewers independently double screening. Data extraction and an in-depth quality assessment conducted by one author and checked by two others. Of 1466 original articles identified, 68 studies were included and key findings outlined for impetigo, scabies, crusted scabies, atopic dermatitis, head lice and molluscum contagiosum. Recommendations for each condition based on the available evidence are provided. The importance of assessing literature relevant to the populations with heavy burden of skin infections is outlined in this systematic review. We have summarised updates to this literature, which may benefit in developing guidelines for skin infection management similar to the National Healthy Skin Guidelines for Australia.

A severe head louse (Pediculus humanus capitis) infestation: Timeline, pathogen detection, kdr-gene screening and morphological anomalies of lice.

Lice are assuming an increasing importance in forensic investigations, given their capacity to provide information about an individual's care. Head louse pediculosis is a frequent condition in school-age children and can be properly controlled using topical treatments combined with good personal hygiene. Prolonged and chronic infestations may result in more serious outcomes including severe iron deficiency anaemia. We conducted entomological and laboratory investigations of a head louse infestation in a 12-year-old girl who experienced severe anaemia and subsequent death. Numerous lice were found postmortem on the head, face and neck of the patient, as well as on bedding and clothing. Analysis of nits on individual hairs determined that the louse infestation had been present for at least 166 days. The lice had some morphological traits characteristic of body lice: the third antennal segment in some specimens was distinctly longer than wide, and the apices of some paratergal plates did not extend into intersegmental membranes, while other morphological features were characteristic of head or body lice. All lice were heterozygous for the T917I kdr genotype, a marker of permethrin resistance. Nineteen (79.2%, 95%CI 59.5%-90.8%) louse DNA samples tested TaqMan positive for Acinetobacter (Moraxellales; Moraxellaceae) sp. Available information and laboratory findings are further discussed regarding their possible contribution to the negative outcome of this case. We stress the impact head louse pediculosis can have on children with limited parental attention, and how severe head louse infestation may serve as warning sign of neglect, and other high-risk situations.

Prevalence of pediculosis among primary school children in Tunisia

Background: Pediculus humanus capitis (head lice) infestation is a global health concern, yet no study has examined its occurrence among primary school children in Tunisia. Aim: To assess the prevalence of Pediculus capitis and its epidemiological characteristics among primary school children living in rural and urban areas of Monastir, Tunisia. Methods: We used 2-step stratified cluster sampling to randomly select 2396 children from 14 primary schools in Monastir during the 2022/2023 academic year. Head lice infestation was assessed through visual inspection of the hair, and data on the socio-demographic characteristics, lifestyle and pediculosis history of the children were collected. We used SPSS version 20 to analyse the data and used descriptive statistics to rate the frequencies. Multivariate logistic regression was used to examine the association between pediculosis and the predictor variables. Results: Overall infestation rate was 17.5% (95% CI 16.0–19.1%); infestation was 5 times higher among girls (29.1%) than boys (6.3%). Schoolchildren living in crowded family households, those in the third and fourth grades and whose parents had low education level were more exposed to infestation. Combing frequency, comb sharing and history of previous infestation had significant impact (P < 0.05) on the prevalence of pediculosis. Multivariate logistic regression showed gender and treatment outcome as the main potentiating factors. Conclusion: These findings highlight the need for pediculosis prevention and integrated health promotion programmes among primary school children and their parents, teachers and nurses in Monastir and other parts of Tunisia.

Crimean-Congo haemorrhagic fever in Iraq

Background: Pediculus humanus capitis (head lice) infestation is a global health concern, yet no study has examined its occurrence among primary school children in Tunisia. Aim: To assess the prevalence of Pediculus capitis and its epidemiological characteristics among primary school children living in rural and urban areas of Monastir, Tunisia. Methods: We used 2-step stratified cluster sampling to randomly select 2396 children from 14 primary schools in Monastir during the 2022/2023 academic year. Head lice infestation was assessed through visual inspection of the hair, and data on the socio-demographic characteristics, lifestyle and pediculosis history of the children were collected. We used SPSS version 20 to analyse the data and used descriptive statistics to rate the frequencies. Multivariate logistic regression was used to examine the association between pediculosis and the predictor variables. Results: Overall infestation rate was 17.5% (95% CI 16.0–19.1%); infestation was 5 times higher among girls (29.1%) than boys (6.3%). Schoolchildren living in crowded family households, those in the third and fourth grades and whose parents had low education level were more exposed to infestation. Combing frequency, comb sharing and history of previous infestation had significant impact (P < 0.05) on the prevalence of pediculosis. Multivariate logistic regression showed gender and treatment outcome as the main potentiating factors. Conclusion: These findings highlight the need for pediculosis prevention and integrated health promotion programmes among primary school children and their parents, teachers and nurses in Monastir and other parts of Tunisia.

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

ABSTRACT 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.

Presence of the knockdown resistance (kdr) mutations in the head lice (Pediculus humanus capitis) population in the North of Iran.

Head lice infestation continues to be a major health problem worldwide. In order to solve this problem, frequent use of pediculocides has caused growing resistance among head lice population. This study aims to investigate the presence of the knockdown resistance (kdr) mutation in the head lice population in northern Iran. Adult head lice were collected from 115 infested individuals referring to the health centers in different parts of Mazandaran province, northern Iran. 38 samples were randomly selected, and Polymerase chain reaction (PCR) was used to amplify a 332-bp and ⁓ 900-bp fragment of the α-subunit of the voltage-sensitive sodium channel (VSSC) gene. According to the analysis of a 332-bp fragment of the VSSC gene, the frequency of kdr T917I mutation including homozygous susceptible (SS), heterozygous resistant (RS), and homozygous resistant (RR) were 45.83%, 12.5%, and 41.66%, respectively. The total frequency of the resistance allele was 54.16%. The results of the 900-bp fragment of the VSSC gene showed two new mutations in the IIS1-2 extracellular loop (H813P) and IIS2 (S825R) and old well-known kdr mutations (M815I-T917I-L920F). The results of Hardy-Weinberg's exact equilibrium test showed that the frequency of genotypes in the studied areas is different from expectations. Moreover, a positive inbreeding coefficient value (F is >0) was found in studied areas which indicated an excess of homozygotes. Overall, the results showed a high frequency of resistant alleles in the northern region of the country. Therefore, it is necessary to develop appropriate control programs for the treatment of pediculosis.

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.

Measuring local genetic variation in permethrin-resistant head lice (Phthiraptera: Pediculidae) from Buenos Aires, Argentina.

The cosmopolitan ectoparasite human head louse, Pediculus humanus capitis (De Geer)(Phthiraptera:Pediculidae), affects mostly school-aged children, with infestations reported every year mainly due to louse resistance to pyrethroids. One of the main resistance mechanisms of pyrethroids is the target site insensitivity (kdr), which is caused by single-nucleotide point mutations (SNPs) located in the voltage-sensitive sodium channel gene. In this study, we analyzed individual head lice toxicologically via the description of their susceptibility profile to permethrin and genetically through the genotypification of their kdr alleles as well as nuclear microsatellite loci. Lice were collected from 4 schools in the city of Buenos Aires, Argentina. The resistance ratios varied from 33.3% to 71.4%, with a frequency of the T917I kdr mutation of 87.31% and with 83.6% of the head lice being homozygous resistant to pyrethroids. Microsatellite data indicated that all the louse school populations had genotype proportions that deviated from Hardy-Weinberg expectations, with FIS > 0 reflecting a deficit of heterozygotes. Bottleneck analysis suggested that all louse school populations underwent a recent reduction in population sizes, while 3 of the 4 schools had gene flow values around 1, indicating ongoing gene flow among those schools. Our study suggests that school louse populations in the city of Buenos Aires may form a metapopulation, where each school represents a small population that undergoes extinction and recolonization processes under strong permethrin selection. This is the first multilevel analysis integrating toxicological, kdr-genotyping, and microsatellite data in human louse populations.

Knowledge and Practice of Primary School Teachers Regarding Pediculosis Capitis in Baghdad, Iraq

Abstract Background: Pediculosis is a disease which is caused by the ectoparasite Pediculus humanus capitis. There is an estimated 19% global prevalence of head lice infestation among schoolchildren. Health education programs have a beneficial impact on the prevention and control of the disease. Increasing knowledge, changing attitudes and behaviors, and improving personal hygiene practices reduce the morbidity and prevalence of pediculosis capitis. Aim of Study: The aim of the study was to assess the knowledge and practice of primary school teachers about pediculosis capitis and to find the association of studied variables with knowledge and practice scores. Patients and Methods: A cross-sectional study was conducted in 20 primary schools in Baghdad, Iraq, from November 1, 2022, to January 31, 2023. It included 351 primary school teachers who had worked for at least 1 year. A questionnaire was distributed to teachers at selected schools for assessment of knowledge and practice. Results: In this study, 20.5% of studied cases had poor knowledge, 58% had fair and 21.5% had good knowledge. Regarding practice level, 43% of studied cases had poor, 37% had fair and 20% had good practice about pediculosis capitis. Poor knowledge and poor practice are significantly higher among participants with an institute level of education and lower duration of work, among singles, those who did not have children who had arts or sports specialties, and those who did not have pediculosis capitis cases. A strong positive correlation was noticed between knowledge and practice scores. Conclusion: The knowledge scores were fair, while the practice scores were poor. Multiple sources are considered a major source of information. There is no association between the gender of the participant and the level of knowledge and practice parameters.

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.

High mitochondrial gene diversity of Pediculus humanus capitis among children in northern Iran.

The head louse, Pediculus humanus capitis, is an obligate ectoparasite and its infestation remains a major public health issue worldwide. Determining the genetic characteristics of the existing clades is essential to identify the population structure and to develop head lice-control programs. Hence, we aimed to investigate the genetic diversity of head lice among infested individuals in northern Iran. Adult head lice were collected from 100 infested individuals referring to the health centers throughout five geographical regions in Mazandaran Province, Iran. Partial fragments of the mitochondrial cytb gene were amplified by PCR, then consequently sequenced. The results of the phylogenetic tree of collected head lice confirmed the existence of two clades, A and B, in the studied areas. Thirteen haplotypes were detected in the studied populations, of which 11 were novel haplotypes. Clade A was the dominant form and accounted for 75% of samples, while clade B included the rest. Haplotype and nucleotide diversity were 0.999 and 0.0411, respectively. Clade A and B of Pediculus humanus capitis exist among the human populations of northern Iran. We observed high genotypic diversity of this head lice.

OPTIMAL COMBINATION OF TOLUENE AND CLOVE OIL (Syizigium aromaticum) IN THE PROCESS OF CLEARING THE PERMANENT PREPARATION PEDICULUS HUMANUS CAPITIS

Clearing is a vital process in microscopy, aimed at enhancing the transparency of tissue preparations for clearer observation of insect structures. Despite its effectiveness, Toluene poses safety concerns due to its explosive nature. Therefore, clove oil (Syzygium aromaticum) has been explored as a safer alternative. This study evaluates the quality of permanent preparations of Pediculus humanus capitis using both toluene and clove oil. Comparative tests were conducted, treating adult head lice specimens with each solvent for three repetitions. Permanent preparations were assessed for clarity, color quality, and morphological integrity. Results indicate a significant difference in quality between the two methods. Toluene yielded mainly poor-quality preparations, while clove oil resulted in a higher proportion of preparations of good quality. The Mann-Whitney test confirmed the significance of this difference (p = 0.002). This study highlights the efficacy of clove oil as a safer alternative to toluene in the clearing process, contributing to entomological practices and chemical safety.

The Composition and Biochemical Properties of Strophantus (Apocynaceae), with a Focus on S. sarmentosus

The genus Strophantus belongs to the Apocynaceae family of flowering plants which grows primarily in tropical Africa. The plants are widely used in traditional herbal medicine. S. sarmentosus, in particular, is used for the treatment of, e.g., joint pain and rheumatoid arthritis, wound infections, head lice, diarrhea, snake bite, and eye conditions. Despite its widespread use, dedicated research characterizing its bioactive plant components is scarce. Investigations have focused mainly on its cardenolides because of their cardioactivity and historical use as cardiotonic. There are also studies concerning the antibacterial, antioxidant, and anti-inflammatory activity of plant extracts. This review summarizes the present knowledge surrounding the biochemical and analytical research on Strophantus, in general, and S. sarmentosus, in particular, and describes the current state of the field based on the available scientific literature.

Study of prevalence of Head Lice (Pediculus Humanus Capitis) Among Schoolchildren in the Zawiya Region, Libya

Head lice are external parasitic insects, obligatory parasitism on humans, and their presence is widespread in all countries of the world. It affects children and adults, and children are more affected, and girls are more affected than boys. The sample size was about 3795 male and female students, with an average of 292 male and female students in each school. The percentage of boys was 52%, compared to 48% of girls. The number of people infected with the head lice parasite reached 232 male and female patients, representing a rate of 6.1%. While the number of male students infected with the head lice parasite reached 86 boys, out of the total number of boys, numbering 2,115 students, and their percentage was 4%, while the number of girls infected with the head lice parasite reached 146, out of the total number of girls, numbering 1,448 girls, and their percentage was 10% girls infected with head lice. Head. The highest infection rate in one of the schools was 32%, while the percentages in the rest of the schools ranged from 1% to 9%. The infection rate in the first semester was 9%, while in the second semester the percentage was 6.4%, while in the third semester the infection rate was 6.3%, while in the fourth semester the percentage was 6.2%, while the percentage of infected students in the fifth semester was 5.3%, in the semester Sixth, the percentage was 2.4%, which is considered the lowest percentage. The value of Sig = 0.000, which is less than 0.05, showed that the difference between the percentage of injuries in the years of study is a significant difference between the average of injuries and the years of study.

Pediculosis and Factors Affecting Its Prevalence among Schoolchildren in Amol City, Northern Iran.

Head louse infestation, pediculosis, is a serious health problem worldwide. Infected children usually suffer from itching, allergies, and secondary infections besides psychological disorders such as depression and lack of self-confidence leading to school failure. This study aimed to investigate the status of pediculosis and its determinant factors among schoolchildren in Amol City, Northern Iran. This study included 228 schools frequented by about 20017 students. Pediculosis was determined by careful examination of students' hair on the scalp, back of the neck, and around the ears. The diagnosis was based on observation of live adults, nymphs, and nits. A questionnaire was used to record the personal and demographic characteristics of participants. This study revealed that the prevalence of pediculosis among schoolchildren during all schooling seasons (autumn, winter, and spring) correlated with sex: the prevalence being higher among girls than boys (p= 0.00). In addition, the highest rates of pediculosis occurred during the autumn season (p= 0.00). The public schools accommodated higher numbers of louse-infected students than the private ones (p= 0.00). While head louse occurred at higher frequencies in long hair over the schooling year, dandruff had anti-louse effects (p= 0.00) during cold seasons, autumn, and winter. Socioeconomic status and educational level of parents played determinant roles in head louse prevalence (p= 0.00). Schoolchildren coming from socioeconomically well-situated families had lower rates of head louse infestation. Our results showed that head pediculosis was a serious health problem among schoolchildren in Amol city and its prevalence and severity tended to be multifactorial.

The Use of Rabbits Used to Propagate Human Lice for Research.

The globally important human diseases of trench fever, epidemic typhus, and relapsing fever are vectored by the human louse Pediculus humanus humanus. Although these conditions are epidemically quiescent at present, they persist in socially dysfunctional situations of war, deprivation, and crowding. The taxonomically closely related head louse, Pediculus humanus capitis, does not respect economic or social status and is quite common in most countries. The 2 types of lice are now recognized as conspecific ecotypes of a single species. While the body louse has been adapted for propagation in the laboratory by feeding in vivo on live rabbits, a similar animal model has not been developed for the host-specific head louse. Accordingly, research for treatment and control of the head louse has largely been performed by using laboratory-reared body lice. This review describes methods for the propagation of body lice in the laboratory and outlines at least 4 areas of research that require sufficient numbers of aged body louse cohorts produced in rabbits for use in controlled studies: 1) pediculicide development and resistance, 2) immunity and vaccine potential, 3) endosymbiotic bacteria needed by lice for nutrition, and 4) lice as vectors of human disease. The review concludes with a discussion of several ethical issues involved with the standard method of using unsedated rabbits and recommends consideration of providing sedating anesthetics for rabbits used in louse feeding procedures.

Optimizing Fixation Duration for Enhanced Clarity in Pediculus humanus capitis Whole Mount Preparations Using 10% KOH at 70°C

This study evaluates the optimal fixation duration using 10% potassium hydroxide (KOH) at 70°C for whole mount preparations of Pediculus humanus capitis (head lice). Accurate head lice identification is crucial for effective public health management. Specimens were fixed for 20, 25, 30, 35, and 40 minutes at 70°C, then processed through rinsing, acetic acid treatment, dehydration, and clearing before mounting for microscopic examination. Results showed that 25 minutes of fixation provided the clearest and most detailed preparations. This duration effectively achieved tissue dehydration and clarification without significant damage. Fixation for 20 minutes was insufficient, resulting in opaque specimens due to incomplete KOH diffusion. Conversely, 40 minutes of fixation caused over-fixation, leading to tissue damage and poorer color quality. The study underscores the importance of finding the right fixation duration. While shorter times are inadequate, longer durations can degrade specimen quality. A 25-minute fixation at 70°C is optimal for balancing clarity and structural preservation, improving head lice identification. This method enhances the quality of whole mount preparations and provides practical guidance for accurate and reliable ectoparasite examination in clinical and research settings.

The Association between Gender, Personal Hygiene Indicators, and Occupancy Density with the Incidence of Pediculosis Capitis at Madrasah Tsanawiyah Pondok Pesantren (Ponpes) Nurus Sunnah Semarang

Background: Pediculosis capitis is one of the neglected tropical diseases (NTDs) caused by Pediculus humanus capitis, an obligate ectoparasite that lives parasitically on human skin. This disease is most common in women, in people with poor personal hygiene, and in densely populated areas. Boarding schools are densely populated and pose a risk for transmission of pediculosis capitis due to the many interactions among residents. Purpose: This study aims to investigate the association between gender, personal hygiene indicators, and occupancy density with the incidence of pediculosis capitis at Madrasah Tsanawiyah Pondok Pesantren Nurus Sunnah Semarang. Methods: In this cross-sectional observational study, all the junior high school students at Ponpes Nurus Sunnah were included in a total of 49 subjects. The data were collected by filling out questionnaires, doing a direct examination of the hair, and counting the measurements of the room area. Data analysis was performed using SPSS 23.0 for Windows. Result: Pediculosis capitis infestation was found among 13 (26.5%) students, with a higher incidence in females (46.4%) than males (0%), in respondents with the habit of combing hair using a personal comb (37.1%), and in non-densely populated areas (58.8%). There was an association between gender (p=0.000), the habit of combing hair using a personal comb (p=0.006), and occupancy density (p=0.000) and the incidence of pediculosis capitis. Conclusion: Gender, the habit of combing hair using a personal comb, and occupancy density are associated with the incidence of pediculosis capitis...