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

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Pediculosis capitis risk factors in schoolchildren: hair thickness and hair length.

The human head lice is a cosmopolitan ectoparasite that causes pediculosis. The main way of spreading lice is through direct head-to-head contact. It is popular knowledge that some individuals are more susceptible to contracting head lice than others. Reports of individuals who have never been affected by the disease are common, even living in the same environment and under the same conditions as people who regularly have lice infestations. Previous research has been carried out on the risk of this infection associated with different human factors like gender or age. However, studies on the influence of the individual hair characteristics are scarce. The objective of the study was to analyze the pediculosis risk using geographical location, gender, age and individual hair characteristics as variables. Pediculosis was diagnosed through the detection of living lice in the hair. This cross-sectional school-based epidemiological study was conducted in 310 schoolchildren aged 1 to 13 years of schools in 4 municipalities situated in the State of Paraná, Brazil. The prevalence of head louse infection in primary school students was 49.35 %. The Odds Ratio of presence of pediculosis (OR) was estimated using multivariate logistic regression analysis. The results obtained indicate that hair length and thickness increase the risk of infection. Furthermore, the inclusion of hair color, hair shape, kind of hair-scale as covariates increases the risk of pediculosis, indicating that these variables partly explain this susceptibility and that pediculosis is independent of gender. A smaller hair diameter may favor insect fixation to the hair in the nymphal phases. These results may explain why girls are a greater risk as they let their hair grow for cultural reasons, i.e., being of female gender is an agglutinating variable. The conclusions drawn may explain the discrepancies obtained in previous analyses.

Prevalence of permethrin-resistant kdr mutation in head lice (Pediculus humanus capitis) from elementary school students in Jeddah, Saudi Arabia.

Head lice (Pediculus humanus capitis) are a major global concern, and there is growing evidence of an increase in head lice prevalence among Saudi schoolchildren. The purpose of this study is to investigate the prevalence of an insecticidal resistance mutation in head lice collected from schoolchildren. A polymerase chain reaction (PCR) was used to amplify a segment of the voltage-gated sodium channel gene subunit to assess the prevalence and distribution of the kdr T917I mutation in head lice. Subsequently, the restriction fragment length polymorphism (RFLP) patterns revealed two genotypic forms: homozygous-susceptible (SS) and homozygous-resistant (RR). The results showed that 17 (37.80%) of the 45 samples were SS, whereas 28 (62.2%) were RR and T917I and L920F point mutations were found in the nucleotide and amino acid sequences of RR. Compared to other nations, the frequency of permethrin resistance mutation in the head louse population in Saudi Arabia was low. This study provides the first evidence of permethrin resistance mutation in human head lice in Saudi Arabia. The findings of this study will highlight the rising incidence of the kdr mutation in head lice in Saudi Arabia.

HEAD LOUSE PALEOEPIDEMIOLOGY IN THE OSMORE RIVER VALLEY, SOUTHERN PERU.

Recent studies of louse ectoparasites from mummies have developed robust data sets that allow a true epidemiological approach to the prehistory of louse parasitism. One epidemiological principle is that the binomial of overdispersion is normally negative, meaning that in a host population, parasites are aggregated in a few individuals. We demonstrate the overdispersion of lice in 3 different prehistoric communities that differ along 3 axes or variables: environmental setting, socioeconomic status, and cultural affiliation. Distinct cultural practices could have been involved in different patterns of louse infestation. Prevalence, intensity, and abundance of infestations exhibit statistically significant differences between the communities. We also find differences in prevalence between subadults and adults that contrasted by cultural affiliation and suggest conditions different from those seen today. We show that overall prevalence was affected primarily by ecological setting, not socioeconomic status nor cultural affiliation. These findings demonstrate that statistical analysis of archaeological data can reveal the states of infestation in past populations with lifestyles not seen in modern people. Our approach paves the way for future comparisons of subpopulations within archaeological communities.

First Detection of Acinetobacter baumannii in Pediculus humanus capitis from Latin America.

Several studies have documented the presence of Acinetobacter baumannii, a known multi-drug-resistant pathogen, in the human head louse, Pediculus humanus capitis. Since no reports from countries in Latin America have been published, the aim of the present study was to determine whether A. baumannii was present in head lice specimens collected in this geographic region. Head lice specimens from Argentina, Colombia, and Honduras were analyzed. PCR assays were performed to confirm the specimens' species and to investigate whether the DNA of A. baumannii was present. The products of the latter were sequenced to confirm bacterial identity. Altogether, 122 pools of head lice were analyzed, of which two (1.64%) were positive for A. baumannii's DNA. The positive head lice had been collected at the poorest study site in Honduras. The remaining specimens were negative. This study is the first to report the presence of A. baumannii in human head lice from Latin America. Further investigations are required to elucidate whether these ectoparasites can serve as natural reservoirs or even effectively transmit A. baumannii to humans.

Pediculosis capitis and scabies in nurses from Eastern Poland - occupational risk and environmental determinants.

INTRODUCTION AND OBJECTIVE: Nurses are a group of healthcare professionals particularly vulnerable to infestations by Pediculus humanus capitis and Sarcoptes scabiei var. hominis contracted from patients under their medical care. MATERIAL AND METHODS: The cross-sectional study included 322 professionally active nurses within public healthcare units in eastern Poland. The research tool was a questionnaire collecting anonymized data on the occurrence of pediculosis capitis and scabies in nurses, and their patients, concerning the environmental determinants in the period 2001-2013. The study was retrospective and participation of nurses was voluntary. RESULTS: The obtained results indicated that 24.8% and 9.9% of the 322 respondents were infested by head lice and scabies mites, respectively. During their professional work, most nurses contracted head lice once (76.2%) while others (23.8%) were infested twice or more. The respondents did not declare repeated occupational scabies. The risk of contracting pediculosis capitis and scabies was not related to the length of service, but increased with the rise in the number of patients provided with nursing care. In the head lice-infested patients, the majority were aged 6-10 years (31.3%), while in the case of scabietic patients, children aged 0-5 years prevailed (26.4%). CONCLUSIONS: In medical care facilities, regular hygienic checks of both patients and medical staff, covering the condition of the skin and scalp, should be mandatory. The spread of pediculosis capitis and scabies among nurses can be reduced by the implementation not only of protective procedures mitigating occupational risk, but also the improvement of working conditions in medical facilities.

Assessment of the Prevalence of Head Lice Infestation and Parents' Attitudes Towards Its Management: A School-based Epidemiological Study in Istanbul, Türkiye

OBJECTIVE: Head lice infestation (HLI), caused by Pediculus humanus capitis, is an important public health problem worldwide, especially in primary school children. The aim of this study is to investigate HLI level, related factors, and families' knowledge levels and attitudes about HLI in two primary schools in a relatively low socio-economic region in Istanbul. METHODS: A questionnaire on HLI was developed initially and delivered to all children and parents in the school. A total of 340 primary school students, aged between 6-12, were enrolled in the study after the consent of their parents. Their hair were examined for HLI with special combs at their schools, and free anti-lice shampoos were given to parents of positive children. A total of 951 completed questionnaires were received and evaluated with chi-square test using the SPSS® 17.0 program, and the differences of p<0.05 were considered significant. RESULTS: Number of boys in the study was slightly higher than the girls (176 vs. 164). HLI was detected in 32 (9.4%) of 340 children; seven had live adult lice on their hair while 25 had only the nits. HLI was obviously more common in girls (16.4%), compared to boys (2.8%). Analysis of 951 questionnaires revealed a statistically significant difference between HLI and infrequent bathing (p<0.05). The differences between HLI and the education levels of parents, income, the number of siblings and in contact with animals were not found to be significant (p>0.05). CONCLUSION: HLI is still a common health problem, especially in girls in primary schools. Parents are aware of the relationship between the hygiene and prevention against HLI, but low socio-economic resources seem to be important determinants. Regular combing and training activities in primary schools, in coordination with the local authorities and parents are no doubt useful in reducing the incidence of HLI among the children.

Prevalence of head louse infestation among primary schoolchildren in the Republic of Korea: nationwide observation of trends in 2011-2019.

Head louse infestation is a significant public health problem across the world, particularly among preschool and primary schoolchildren. This study investigated the trends of head louse infestation in the Republic of Korea over a 9-year period (2011-2019), targeting primary schoolchildren in 3 areas of Seoul, 4 other large cities, and 9 provinces. A survey was administered annually by the health staff of each regional office (n= 16) of the Korea Association of Health Promotion (KAHP). The branch offices of KAHP examined a total of 51,508 primary schoolchildren, comprising 26,532 boys and 24,976 girls. Over the 9-year survey, a total of 1,107 (2.1%) schoolchildren tested positive for adults and/or nits of Pediculus humanus capitis. The prevalence was 2.8% (133/4,727) in 2011-2012 and gradually decreased to 0.8% (49/6,461) in 2019 (P< 0.05). Head lice were found more frequently in girls (3.0%; 746/24,976) than in boys (1.4%; 361/26,532) (P< 0.05). In terms of geographic localities, the highest infestation rate, 4.7% (average prevalence over 9 years), was observed in southern Seoul (Gangnam branch of KAHP), whereas the lowest infestation rate, 0.7%, was seen in Gyeongsang (north and south provinces) and western Seoul. Although the prevalence decreased significantly during the 9-year period, head louse infestation remains a health and hygiene issue among primary schoolchildren in the Republic of Korea. Regular surveys along with health education are needed to further improve children's hair hygiene.

Histological confinement of transglutaminase-mediated nit sheath crosslinking is essential for proper oviposition and egg coating in the human head louse, Pediculus humanus capitis.

BACKGROUND: Head louse females secrete liquid gel, which is mainly composed of the louse nit sheath protein 1 (LNSP1) and LNSP2, when they lay eggs. The gel is crosslinked by transglutaminase (TG) to form the nit sheath, which covers most of the egg except the top operculum area where breathing holes are located. Knowledge on the selective mechanism of nit sheath solidification to avoid uncontrolled crosslinking could lead to designing a novel method of louse control, but no information is available yet. METHODS: To elucidate the crosslinking mechanisms of nit sheath gel inside the reproductive system of head louse females, in situ hybridization in conjunction with microscopic observation of the oviposition process was conducted. RESULTS: Histochemical analysis revealed that LNSP1 and LNSP2 are expressed over the entire area of the accessory gland and uterus, whereas TG expression site is confined to a highly localized area around the opening of posterior oviduct. Detailed microscopic observations of oviposition process uncovered that a mature egg is positioned in the uterus after ovulation. Once aligned inside the uterus, the mature egg is redirected so that its operculum side is tightly held by the ventral end of the uterus being positioned toward the head again and its pointed bottom end being positioned toward the dorsal end of the uterus, which functions as a reservoir for the nit sheath gel. CONCLUSIONS: Physical separation of the TG-mediated crosslinking site from the ventral end of the uterus is necessary to avoid uncontrolled crosslinking inside the uterus and to ensure selective crosslinking over only the lower part of egg without any unwanted crosslinking over the operculum during oviposition.

Embryonic Development of Pediculus humanus capitis: Morphological Update and Proposal of New External Markers for the Differentiation Between Early, Medium, and Late Eggs.

BACKGROUND AND OBJECTIVES: The head louse Pediculus humanus capitis is a cosmopolitan ectoparasite that causes pediculosis. In the study of human lice, little research focuses on embryonic development. Currently, external markers of embryonic development represent a new approach in the evaluation of ovicidal drugs. The objective of this work was to update the morphology of embryonic development and propose novel external markers to differentiate between early, medium, or late P. h. capitis eggs. METHODS: Using stereoscopic light microscopy, we describe the morphological characteristics of P. h. capitis eggs with a special focus on embryonic development. RESULTS: The morphological analysis of the eggs revealed the presence of an operculum with ten aeropyles, although no micropyles were observed. For the first time, the presence of defective eggs that were non-viable due to the apparent absence of yolk granules was documented. The early eggs presented yolk granules and developing germ bands, while the medium eggs presented an embryonic rudiment and the outlines of the eyes and limbs. In late eggs, the head with eyes and antennae, the thorax with three pairs of legs, and the abdomen with six pairs of spiracles were observed as formed structures. At the end of this stage, the embryos acquired the morphology of the nymph I stage. CONCLUSION: We propose novel biomarkers (e.g., the presence of spiracles and antennae, the proportion of the egg occupied by the embryo) to facilitate the differentiation between the developmental stages. The updated morphological characteristics of P. h. capitis eggs facilitate the standardization of toxicological tests in the quest for ovicidal drugs.

A comprehensive survey of permethrin resistance in human head louse populations from northwest Iran: ex vivo and molecular monitoring of knockdown resistance alleles.

BACKGROUND: Head louse infestation is an important public health problem, and expanding resistance to permethrin is a major challenge to its control. The mapping and detection of pyrethroid resistance are essential to the development of appropriate treatments and ensure the effectiveness of current measures. The aim of this study was to present the phenotypic and genotypic basis of permethrin resistance and identify knockdown resistance (kdr) mutations in head louse populations in northwestern Iran. METHODS: Adult head lice were collected from 1059 infested girls in Ardebil, East Azerbaijan, West Azerbaijan and Zanjan Provinces, northwestern Iran. The toxicity of permethrin and the possible synergistic effect of piperonyl butoxide (PBO) on this toxicity were assessed using bioassays. Fragments of voltage-sensitive sodium channels (vssc) and cytochrome b (cytb) genes were amplified and analyzed for the detection of knockdown resistance (kdr) mutations and mitochondrial groups. Moreover, genotypes of the two hot spot regions of the vssc gene were determined by melting curve analysis of amplicons. RESULTS: A total of 1450 adult head lice were collected during 2016-2021. Live lice were exposed to a dose of 1% permethrin for 12 h, and the median lethal time (LT50) and time to achieve 90% mortality (LT90) were determined to be 6 and 14.8 h, respectively. Topical application of 2 and 16 ng permethrin per louse resulted in 25% and 42.11% mortality, respectively. Pre-exposure of samples to 3% piperonyl butoxide had no synergistic effect on the effects of permethrin. Analysis of the 774-bp vssc gene fragment showed the presence of the M815I, T917I and L920F mutations, wild-type and T917I mutation, in 91.6%, 4.2% and 4.2% of samples, respectively. Investigation of the mitochondrial cytb gene demonstrated the predominance of clade B. The frequency of domain II segment 4 (S4)-S5 kdr genotypes in mitochondrial groups was identical, and heterozygotes were present in 93.5% of samples. A significant difference was detected in the frequency of domain IIS1-S3 kdr genotypes, and the frequency of resistant alleles and heterozygotes was higher in clade B than in clade A. CONCLUSIONS: The presence of kdr mutations in the vssc gene and the non-synergist effect of PBO indicate that pyrethroid target site insensitivity is the main resistance mechanism. This phenomenon and the high frequency of resistant alleles necessitate that new pediculosis management programs be developed. Further studies need to be conducted to identify all factors contributing this resistance and to develop alternative pediculicides.

Head lice: an inexpensive bioassay for use as guidance for healthcare workers monitoring treatment failures for insecticide resistance (1994-1999).

Head lice, Pediculus humanus capitis De Geer (Psocodea: Pediculidae) that failed to respond to pyrethroid insecticide-based treatment products were first identified in London and Cambridge, UK, in 1993 after which reports of treatment failure arose throughout the UK. There was a need amongst healthcare workers for a rapid detection method for resistance that could be used at the community level. A laboratory service was set up so that health professionals could send lice by overnight post for bioassay testing for resistance. In addition, test kits were provided so that testing could either be conducted on site or lice could be shipped to the laboratory on pre-treated test papers so that insecticide exposure could proceed while lice were in transit to the laboratory. Between 1994 and 1999, over 350 samples from 145 locations were tested and during this time populations of lice resistant to pyrethroids, malathion, and carbaryl were identified from all parts of the country, both urban and rural. In some areas, lice were only resistant to one of the insecticides available but in other places lice showed tolerance to all three insecticides used at the time.

Epidemiological aspects of pediculosis by Pediculus humanus capitis (Phthiraptera: Pediculidae) in Minas Gerais: a systematic review / Aspectos epidemiológicos da pediculose por Pediculus humanus capitis (Phthiraptera: Pediculidae) em Minas Gerais: uma revisão sistemática

Abstract Background Head lice, or head pediculosis, is a parasitosis considered a serious public health problem that affects mainly resource-limited countries. Objective To describe epidemiological aspects of the pediculosis capitis in Minas Gerais, in Brazil. Method This systematic review was conducted through the standards established by the Preferred Reporting Items in Systematic Reviews and Metanalyses (PRISMA). PubMed, LILACS, and SciELO databases, as well as the gray literature, were searched. Results Nine of 1,167 studies were included, published between 1988 and 2019. These studies reported a total prevalence of parasitosis that ranged from 1.4% to 57.4%. The prevalence of head lice ranged from 0.0% to 66.7% for males and 2.3% to 57.4% for females, thus being higher in black-skinned people (1.4% to 40.3%). Regarding age, the highest prevalence was 10-12 years old (45.3%). As for the characteristics of the hair, there was a greater infestation in people with long (16.0% to 79.5%), wavy (0.0% to 44.7%), dark (0.0% to 36.6%), with low capillary density (35.4%), and thick hair (39.2%). Conclusion Head pediculosis affects both sexes, different ages, and races, representing an important health problem in Minas Gerais, not only due to the presence of ectoparasite but also to the secondary complications that can be generated from this parasitism.

Resumo Introdução A pediculose de cabeça é uma parasitose considerada um sério problema de saúde pública, afetando principalmente países com recursos limitados. Objetivo Descrever os aspectos epidemiológicos da pediculose de cabeça em Minas Gerais, Brasil. Método Revisão sistemática conduzida por meio dos padrões estabelecidos pelo Preferred Reporting Items in Systematic Reviews and Metanalyses (PRISMA). Foram pesquisadas as bases de dados PubMed, LILACS e SciELO, bem como a literatura cinza. Resultados Nove de 1.167 estudos foram incluídos, publicados entre 1988 e 2019. Relatou-se uma prevalência total da parasitose que variou de 1,4% a 57,4%. Ela variou de 0,0% a 66,7% para homens e 2,3% a 57,4% para mulheres, sendo maior em pessoas de cor negra (1,4% a 40,3%). Em relação à idade, a maior prevalência foi de 10 a 12 anos (45,3%). Quanto às características dos cabelos, houve maior infestação em pessoas com cabelos longos (16,0% a 79,5%), ondulados (0,0% a 44,7%), escuros (0,0% a 36,6%), com baixa densidade capilar (35,4%) e fios grossos (39,2%). Conclusão A pediculose atinge ambos os sexos, diferentes idades e raças, representando um importante problema de saúde em Minas Gerais, não só pela presença do ectoparasita, mas também pelas complicações secundárias que podem ser geradas desse parasitismo.

Head Lice Infestation: An Unusual Cause of Iron Deficiency Anemia in a 13-Year-Old Female.

Pediculosis is a parasitic infestation of the human head and body by Pediculus humanus. This is a benign condition commonly seen in children and capable of causing severe pruritus. The parasite thrives on human blood and in some cases, the volume of blood loss over time could be large enough to precipitate anemic symptoms in the patient. We describe the case of a 13-year-old girl who presented with shortness of breath on exertion, palpitations, and easy fatigability. An incidental finding of Pediculus humanus capitis infestation was made during physical examination. Complete laboratory investigations did not reveal other possible causes of anemia, leading to a diagnosis of iron deficiency anemia (IDA) secondary to severe chronic pediculosis. This case highlights a rare and unusual cause of IDA in children caused by pediculosis, and the need for a thorough investigation, close follow-up, and treatment.

First exploratory study of bacterial pathogens and endosymbionts in head lice from a Mayan community in southern Mexico.

Lice represent one of the most neglected group of vectors worldwide, particularly in Latin America. Records of bacterial agents related to head lice are non-existent in this region of the continent. Many of these communities often do not have adequate access to public services and/or health protection. The normalization of this condition prevents them from manifesting discomfort, such as bites and itching, which further aggravates the situation, as they can be vectors of important diseases. For this reason, the aim of this work was to identify the richness of bacterial pathogens (Acinetobacter, Bartonella, and Rickettsia) and endosymbionts (Wolbachia) in head lice of paediatric patients from the indigenous municipality of Hoctun, Yucatan, Mexico. DNA extraction was performed using the QIAamp DNA Mini Kit. For the detection of bacterial pathogens, fragments of the gltA, rpoB, and 16S rDNA genes were amplified. For the detection of Wolbachia, the wsp gene was amplified. Of the 28 lice analysed, the presence of two genera of bacterial pathogens was detected Acinetobacter (42.9% = 12/28) and Bartonella (7.14% = 2/28). We also detected the endosymbiont Wolbachia (71.42% = 20/28). Our results showed that DNA from three bacteria species (Acinetobacter baumannii, Bartonella quintana, and Wolbachia pipientis) was present with frequencies ranging from 3.57% to 71.42%. This work represents the first exploratory study of the diversity of agents associated with head lice (Pediculus humanus capitis) in Mexico and Latin America. Due to the findings generated in the present study, it is important to perform surveillance of head lice populations to identify the degree of spread of these pathogens and their impact on populations in the region.

Determination of Knockdown Resistance (kdr) Allele Frequencies (T929I mutation) in Head Louse Populations from Mexico, Canada, and Peru.

The head louse Pediculus humanus capitis (De Geer) is a hematophagous ectoparasite that inhabits the human scalp. The infestations are asymptomatic; however, skin irritation from scratching occasionally may cause secondary bacterial infections. The present study determined the presence and frequency of the knockdown resistance (kdr) mutation T929I in 245 head lice collected from Mexico, Peru, and Canada. Head lice were collected manually using a comb in the private head lice control clinic. Allele mutation at T9291 was present in 100% of the total sampled populations (245 lice) examined. In addition, 4.89% of the lice were homozygous susceptible, whereas 6.93% heterozygous and 88.16% homozygous were resistant, respectively. This represents the second report in Mexico and Quebec and fist in Lima.

Head louse infestations before and during the COVID-19 epidemic in Israel.

Head louse infestations caused by Pediculus humanus capitis (Phthiraptera: Pediculidae) are a public health problem in developing and developed countries worldwide. Head to head contact is by far the most common mode of lice transmission. In March 2020, WHO declared the COVID-19 outbreak as a pandemic. Starting from March 2020, the Israeli government established mandatory isolation for extensive periods including closure of school systems for very long time. The aim of the project was to compare the pediculicide sale numbers before the COVID-19 epidemic with those starting of the epidemic in 2020, as a possible marker for changing epidemiology of head lice during the COVID pandemic. Data were collected from a large pharmacy chain in Israel, which provided the actual sales of pediculicides during the years 2010-2020. During the period 2010-2019 a significant increase of pediculicide sales from 281,986 - 498,107 was observed, the highest number being from 2019. In 2020, this number dropped to 294,477, a significant drop compared to previous years and to 2019. The results of this study suggest that head louse infestations are increasing in the last years, while the extended isolation of children due to COVID-19 influenced significantly the infestation rate of children with head lice.

Head Lice Infestation in Schoolchildren, in Poland-Is There a Chance for Change?

Pediculosis capitis is a current and neglected health issue worldwide. The lack of screening programs contributes to the marginalization of the problem and delays therapeutic measures. Our study aimed to analyze the occurrence of this parasitosis in primary schools in Poland and to determine factors contributing to the persistence of its foci. The research tools were two questionnaires: one for primary school children and the other for school managers. While children answered questions about the epidemiology of pediculosis capitis and expressed their opinion on the hygienic condition of infested persons, the school directors were asked about the occurrence of head lice in schools, preventive measures, and institutions supporting schools in combating the infestation. The survey covered the period 2014-2018. Pediculosis capitis was reported in 87.5% of the schools. The greatest number of cases was reported in the group of 6-9 year-olds (68%). Among 4970 children, 16.7% had no knowledge of head lice; however, 57.1% wanted to increase their awareness of the problem. Campaigns on lice were conducted mainly as a result of emerging pediculosis capitis cases, and most schools could not rely on institutional support. Screening programs and preventive educational campaigns should be part of pediculosis capitis control in Poland.

Abametapir for the Treatment of Head Lice: A Drug Review.

OBJECTIVE: This article reviews the pharmacology, safety, efficacy, and clinical importance of abametapir 0.74% (Xeglyze) for the treatment of head lice. DATA SOURCES: From 2020 to May 2021, a systematic review of the MEDLINE and EMBASE databases was conducted using the terms abametapir, Xeglyze, Ha44, and head lice. Bibliographies, Food and Drug Administration (FDA) drug package inserts, and ClinicalTrials.gov were searched for further information. STUDY SELECTION AND DATA EXTRACTION: All relevant full-text articles in English were considered for inclusion, with a final article date range of 1999 to 2020. DATA SYNTHESIS: Abametapir chelates heavy metal cations and inhibits metalloproteinases critical to louse ova development, hatching, and adult survival. In phase II, abametapir had direct ovicidal activity inhibiting 100% of treated louse eggs from hatching, compared with 64% in the vehicle-treated group. In two identical phase III clinical trials, subjects treated with a single 10-minute application of abametapir had greater treatment success compared with vehicle-treated subjects, with 81.1% success versus 50.9% in study 1 (P = 0.001) and 81.8% versus 47.2% in study 2 (P < 0.001). Abametapir was well tolerated, with only mild adverse effects. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE: Abametapir is a newly FDA-approved, single-application treatment for head lice in patients aged 6 months and older. This review highlights the safety and efficacy of abametapir in the treatment of head lice. CONCLUSIONS: In the wake of increasing widespread resistance to first-line treatment options, abametapir offers a safe and effective new treatment option for head lice infestations.

Pediculus humanus capitis: a study of the male genitalia using a combined stereoscopic, confocal laser scanning, and scanning electron microscopy approach.

BACKGROUND: The male genital structures of arthropods are key features in the taxonomic and phylogenetic study of these organisms. The male genitalia of the head louse Pediculus humanus capitis are complex organs which are partly composed of structures that dynamically extrude during copulation. METHODS: Here, we describe the morphology of the genitalia of P. humanus capitis at the copulation stage, and at rest, by using stereoscopic microscopy, confocal laser scanning microscopy (CLSM), and scanning electron microscopy (SEM). RESULTS: CLSM and SEM images revealed that the vesica is composed of two distinct anatomical parts, the proximal lobe and the distal lobe. Both lobes have short and narrow spines, as well as long and wide scales with either sharp or rounded tips. The rounded scales vary in size and have a wavy base and rounded tips, and thus resemble a tongue in appearance. We identified a gland-like area on the penis with 11 shallow circular depressions, and a flat area with 14-16 exit orifices. The apical end of the penis has a foliaceous trifurcation and serves to expel the contents of the ejaculatory duct. These characteristics were recorded for all the specimens analyzed, indicating that these structures are highly conserved; to our knowledge, they have not been previously reported for any suborder of lice. CONCLUSIONS: To the best of our knowledge, our results reveal for the first time the morphological details, and complexity, of the male genitalia of the head louse P. humanus capitis at different stages of copulation. The new approach described here provided information that should be taken into consideration in future research on the genitalia of lice. Application of this approach will also impact the taxonomic and phylogenetic study of other insect taxa.