Cuticular extracts induce aggregation in head lice

The human head lice Pediculus humanus capitis (De Geer) (Phthiraptera: Pediculidae) are strict, obligate human ectoparasites that spends their entire life cycle in the host and cause skin irritation and derived infections. Despite the health-related importance, few studies have evaluated the chemical communication among these insects. Here, we evaluate the response of lice of both sexes to cuticular extracts using two solvents of different polarity (hexane and methanol). Cuticular extracts that elicited an attraction response towards head lice were analysed by gas chromatography-mass spectrometry (GC-MS) to determine the cuticular lipid profile. Both lice sexes were attracted to the hexane extracts but not the methanol extracts, suggesting the non-polarity of the compounds present in the cuticle. Chemical analyses of hexane extracts from males and females showed high similarity in major compounds. This study provides the first evidence that lice respond to cuticle extracts, which may be important to understand aggregation behaviour.

Head lice infestation and the role of some cognitive-behavioral factors in its spread and prevention among adolescent girls: A cross-sectional study in Northwest Iran

Background and Aims

Head lice is a public health problem of worldwide distribution, particularly among school children and girls. Head lice infestation (HLI) can lead to negative social and psychological outcomes such as distress and anxiety in children and their families. Hence, the present study aimed to investigate the role of cognitive-behavioral factors in its spread and prevention among adolescent girls.

Methods

The cross-sectional study was conducted among 276 school-aged adolescent girls from September 2022 to January 2023 in Herris, a city located in Northwest Iran. A multistage cluster random sample was used to recruit adolescent girls in secondary schools. Two schools were randomly selected from five secondary schools. Then, students in each school were randomly selected from a school list. Data were collected using a valid and reliable questionnaire.

Results

The high protective behaviors were significantly associated with the number of family members (ß = 0.158; p value = 0.012). An additional 21.8% of the variation in preventive behaviors was explained by cognitive factors as predictor variables (p value > 0.05). Perceived collective family efficacy, perceived barriers, perceived self-efficacy, and response efficacy were predictors of head lice preventive behaviors, respectively. Among all variables, perceived collective family efficacy was the strongest predictor.

Conclusions

The findings of current research support the determinants of the cognitive-behavioral factors in the spread and prevention of HLI. It is better to involve these factors in school-based educational programs by policymakers and healthcare providers.

Treatment Modalities of Pediculosis Capitis: A Narrative Review

The review has been done to find out the best-suited treatment modality for pediculosis capitis. Pediatric patients frequently experience pediculosis capitis, a head louse infestation brought on by the Pediculus humanus var. capitis. The primary sign of head lice infestation is a scratchy scalp, and the presence of living nits confirms this diagnosis. When a doctor diagnoses pediculosis as a primary bacterial infection, a bacterial impetignization and secondary infection, and cervical and occipital lymphadenopathy might make the clinical diagnosis more difficult. A proper therapy of pediculosis requires screening and treatment of all close contacts. The careful use of topical pediculicidal treatments, especially permethrin lotion and wet combing with a fine tooth comb, is required for the medical treatment of a head louse infestation. We've tried to outline the key points of treating head lice infestations. There are several treatment alternatives suggested, including over-the-counter permethrin and pyrethrin as well as prescription medications including malathion, lindane, benzyl alcohol, and spinosad.

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.

Bartonella quintana transmitted by head lice: an outbreak of trench fever in Senegal

BACKGROUND

Louse-borne trench fever caused by Bartonella quintana is a neglected public health concern, known to be transmitted from body louse faeces via scratching. No viable B. quintana have ever been isolated from head lice before; therefore, their role as a vector is still poorly understood.

METHODS

In Senegal, the implementation of a permanent local surveillance system in a Point-of-Care laboratory (POC) allows the monitoring of emerging diseases. Here, we used culture as well as molecular and genomic approaches to document an outbreak of trench fever associated with head lice in the village of Ndiop. Head lice and blood samples were collected from febrile patients between November 2010 and April 2015. Genomes of two isolated strains of B. quintana were sequenced and analysed.

RESULTS

A total of 2,289 blood samples were collected in the 2010-2015 period. From 2010-2013, B. quintana DNA was detected by PCR in 0.25% (4/1,580). In 2014, 228 blood samples were collected, along with 161 head lice from five individuals. B. quintana DNA was detected in 4·4% (10/228) of blood samples, and in lice specimens collected from febrile patients (61·7%, 50/81) and non-febrile patients (61·4%, 43/70). Two B. quintana strains were isolated from blood and head lice from two different patients. Genomic sequence analysis showed 99·98% overall similarity between both strains.

CONCLUSION

The presence of live B. quintana in head lice, and the genetic identity of strains from patients' blood and head lice during a localised outbreak in Senegal, supports the evidence of head lice vectorial capacity.

Estonian Parents' Awareness of Pediculosis and Its Occurrence in Their Children

Background and Objectives: Pediculosis, or head lice infestation, is a widespread health problem that can affect anyone, regardless of gender, age, or social background. The purpose of this study was to clarify the occurrence of pediculosis among Estonian preschool- and primary school-aged children according to their parents and the parent’s awareness of pediculosis and related behaviors. Materials and Methods: An online questionnaire was completed by the parents of the preschool children (n = 1141) in 2019 and the parents of the elementary school children (n = 362) in 2021. For the descriptive data, t-test, Mann−Whitney or χ2 test, linear regression, and logistic regression analyses were applied. Results: According to the parents, pediculosis had occurred in 34.7% of the children, and more than one-third of pediculosis patients had experienced it more than twice. Lice were mainly acquired from elementary school or preschool and less often from friends, relatives, or training environments. Parents’ knowledge of head lice was rather good; the average score of the correct answers was 14.0 ± 3.4 (max. 20). In the multivariate analysis, higher age (coefficient 0.07, p < 0.001), healthcare education (coefficient 1.19, p < 0.001), and a previous occurrence of pediculosis in a family (coefficient 1.95; p < 0.001) were factors influencing better knowledge. In order to treat the infestation, antilice shampoo and combing were the most often used methods. Conclusion: Despite parents’ awareness, pediculosis infestations continue to be common among our children.

Staying Ahead of Head Lice: Pediculosis Treatment Updates

Pediculosis (head lice) infections are one of the more sensitive issues that may involve the school nurse. In the 3- to 11-year-old age group in the United States, head lice infections are common and can elicit anxiety in students, parents, and school personnel. Head lice do not transmit any communicable diseases and therefore exclusion from school and "no nit" policies are not warranted. Treatment and management for head lice include a range of over-the-counter products and prescription topical and oral medications. Nonpharmacologic and alternative treatments do exist; however, many do not have established efficacy studies, and some can be costly. The school nurse plays an integral role in providing education related to treatment and environmental recommendations for families affected by head lice. Through this education, the nurse can also reduce the stigma and anxiety many feel around the subject of head lice infections.

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.

Evaluation of anti-lice topical lotion of ozonated olive oil and comparison of its effect with permethrin shampoo

BACKGROUND

Pediculosis is an infestation of lice affecting mostly children and spreads by direct contact with the hair of someone infected. Although topical application of a pediculicide such as permethrin shampoo is the most common cure for head lice, the addition of alternative treatments is necessary due to permethrin resistance and some safety concerns, including irritation, burning sensation, tingling, and breathing problems. Recent studies have indicated that ozone, which is an allotropic form of oxygen, may have anti-pediculosis effects.

OBJECTIVE

This study focused on the evaluation of an ozonated olive oil topical lotion for the treatment of pediculosis and the comparison of its effects with permethrin shampoo.

METHODS

121 patients with proven head pediculosis were divided into two groups. They were treated with either topical ozonated olive oil lotion or permethrin shampoo for one week.

RESULTS

It was shown that the ozonation process enormously improved the physico-chemical properties of olive oil. Specifically, acid and peroxide values increased 60 fold and 200 fold, respectively, while there was a sharp decline for the iodine index (81.8±1.28 to 0 g iodine per 100 g). Additionally, all patients who received the ozonated olive oil lotion were entirely cured after one week of treatment, while those who were treated with permethrin, required to receive more. Statistical analysis of the data also proved this claim.

CONCLUSION

The prepared lotion has shown significant effects in controlling head lice. Thus, it can be prescribed as an effective anti-pediculosis medicine which is biocompatible and has high potential.

Epidemiologic evolution of common cutaneous infestations and arthropod bites: A Google Trends analysis

Background

Common cutaneous infestations and arthropod bites are not reportable conditions in most countries. Their worldwide epidemiologic evolution and distribution are mostly unknown.

Objective

To explore the evolution and geographic distribution of common cutaneous infestations and arthropod bites through an analysis of Google Trends.

Methods

Search trends from 2004 through March 2021 for common cutaneous infestations and arthropod bites were extracted from Google Trends, quantified, and analyzed.

Results

Time series decomposition showed that total search term volume for pubic lice decreased worldwide over the study period, while the interest for ticks, pediculosis, insect bites, scabies, lice, and bed bugs increased (in increasing order). The interest for bed bugs was more pronounced in the former Union of Soviet Socialist Republics countries, interest for lice in Near East and Middle East countries, and interest for pubic lice in South American countries. Internet searches for bed bugs, insect bites, and ticks exhibited the highest seasonal patterns.

Limitations

Retrospective analysis limits interpretation.

Conclusion

Surveillance systems based on Google Trends may enhance the timeliness of traditional surveillance systems and suggest that, while most cutaneous infestations increase worldwide, pubic lice may be globally declining.

[For Safer Use of Ivermectin in All Patients]

The difficult experience of treating scabies in an elderly hospital reaffirmed my determination and responsibilities as a pharmacist. In 2000, there was no effective treatment for scabies in Japan. With the Japan Pharmaceutical Association as well as the Japanese Dermatological Association, the indication of ivermectin which is the intestinal fecal nematode was expanded for scabies. Since it was found that the administration of ivermectin through a tube to patients who could not take it orally had a dose loss of 50% depending on the injection method, an appropriate administration method was proposed. However, the oral administration of ivermectin has side effects including systemic liver damage, and external preparations require labor for systemic application, and recurrence from unapplied areas is also a problem. Therefore, we devised a whole-body bathing, in which patients are immersed in a fluid that contains ivermectin. The repeated ivermectin bathing three times a week cured scabies and has no problematic side effects in the clinical trial, suggesting that this method is a safer treatment. Next, in Okinawa, phenothrin-resistant head lice infestation was prevalent, and no medical drug for this infestation is available in Japan yet. Hence, to address this situation, we conducted a clinical trial to investigate the efficacy and safety of a combination regimen of 5% topical phenothrin and the unapproved 0.5% topical ivermectin. Consequently, 92% and 100% effectiveness were obtained in Okinawa and Tsukuba, respectively. As a result, we were able to conduct research aimed to maximize the safety and effectiveness of ivermectin in Japan.

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.

Efficacy and safety of a dimethicone lotion in patients with pyrethroid-resistant head lice in an epidemic area, Okinawa, Japan

Pyrethroid insecticides are the only pesticides approved for the treatment of head lice (pediculosis capitis) infestations in Japan. However, in Okinawa Prefecture, 96% of head lice are resistant to pyrethroids. Here, we conducted a clinical trial to assess the safety and efficacy of a dimethicone preparation against head lice infestations in Okinawa Prefecture. Dimethicone‐containing lotion was applied over the entire scalp three times over a 7‐day period. Lice bodies (nymphs/adults) and eggs (nits) were counted before (day 0) and after treatment (day 8); a subset of eggs was collected to estimate viability based on hatch rate. Efficacy was evaluated based on improvement (reduction) in head lice counts post‐treatment with respect to baseline. Safety was evaluated based on subjects’ scalp condition and adverse event incidence. Utility was a composite end‐point combining efficacy and safety. In total, 35 subjects were enrolled. Efficacy and safety were evaluated in 23 and 35 subjects, respectively. No side‐effects of note were reported during the treatment period. The dimethicone lotion resulted in a utility rating of “marginally useful” or higher in over 80% of the study population, signifying the formulation to be both safe and effective. The dimethicone lotion was also a potent ovicide; 99.4% of eggs collected after treatment failed to hatch when incubated. Eradication of head lice remained successful for at least 4 weeks after the final topical dimethicone application in 25 of the 28 subjects reached by telephone survey. Lice bodies and eggs were genotyped to analyze the prevalence of three knockdown resistance (kdr)‐type mutations within the voltage‐sensitive sodium channel known to confer pyrethroid resistance. One or more kdr mutations were confirmed in 30 of the 32 subjects from whom specimens were collected (93.8%). Dimethicone was confirmed to be both safe and effective in treating pyrethroid‐resistant head lice.

Head Lice at School: Traditional Medicine and Community Engagement

Purpose: The prevalence of head lice in poor rural communities and urban slums is estimated to be between 28% and 43% in Brazil, respectively. Children are among the most affected, often in clusters within schools. We launched a program intending to tackle the social stigma associated with head lice using scientific information and a local traditional remedy as a way to lower the prevalence of head lice in a low-resource community. Methods: A program involving the entire school community and the teachers addressed how to treat head lice and avoid new infestations. An affordable solution widely used in traditional Brazilian medicine was provided for the ones infested. Evaluation of the outcome was based on direct observation and was designed as a satisfaction survey. The study complied with the criteria for Standards for Reporting Qualitative Research (SRQR). Results: Two hundred and eighty participants, including parents and siblings of the school children, took part in the program. Among them, 24% (N=67) had head lice, with girls representing 85% of cases; 74.7% of participants infested with head lice were between 4 and 10 years old; 55.2% (N=37) of participants infested showed no signs of nits or adult lice after the program. Conclusions: This experience suggests that the use of playful activities associated with a well-known and accessible local product to treat head lice in low-income families gathered a high degree of community adherence and may be an important tool in overcoming health inequalities.

Molecular Characterization and Genetic Diversity of Haplogroup E Human Lice in Guinea, West Africa

Pediculus humanus capitis, the head louse, is an obligate blood-sucking ectoparasite that occurs in six divergent mitochondrial clades (A, D, B, F, C and E). Several studies reported the presence of different pathogenic agents in head lice specimens collected worldwide. These findings suggest that head louse could be a dangerous vector and a serious public health problem. Herein, we aimed to study the mitochondrial genetic diversity, the PHUM540560 gene polymorphisms profile of head lice collected in Guinea, as well as to screen for their associated pathogens. In 2018, a total of 155 head lice were collected from 49 individuals at the Medicals Centers of rural (Maférinyah village) and urban (Kindia city) areas, in Guinea. Specimens were subjected to a genetic analysis and pathogens screening using molecular tools. Results showed that all head lice belonged to eight haplotypes in the E haplogroup, with six newly identified for the first time. The study of the PHUM540560 gene polymorphisms of our clade E-head lice revealed that 82.5% exhibited the same polymorphism profile as the previously reported clade A-body lice. Screening for targeted pathogens revealed the presence of Acinetobacter spp., while sequencing highlighted the presence of several species, including Acinetobacter baumannii, Acinetobacter nosocomialis, Acinetobacter variabilis, Acinetobacter towneri and for the first time Acinetobacter haemolyticus. Our study is the first to report the existence of the Guinean haplogroup E, the PHUM540560 gene polymorphism profile as well as the presence of Acinetobacter species in head lice collected from Guinea.

Vaccuuming method as a successful strategy in the diagnosis of active infestation by Pediculus humanus capitis

Most human epidemiological and clinical studies use visual inspection of the hair and scalp to diagnose Pediculus humanus capitis , however this method has low sensitivity to diagnose active infestations (presence of nymphs and adult lice). Vacuuming the hair and scalp has been used as a diagnostic method, but there are no previous data comparing its effectiveness with visual inspection. The aim of this study was to determine the prevalence of overall infestation (nits and trophic stages), of active infestation by Pediculus humanus capitis , and to evaluate the effectiveness of vacuuming in comparison with the visual inspection. Visual inspection was performed by three examiners and vacuuming of the scalp by one investigator, with an adapted vacuum cleaner. A total of 166 children aged 4 to 10 years old were randomly selected from public schools in Southern Brazil. Considering the positive results obtained by both methods, the prevalence of overall infestation was 63.3%, whereas active infestation was 18.7%. The visual inspection was more effective on diagnosing overall infestation, however, its effectiveness to detect active infestation was lower, ranging from 0.6% (RR=3%, p<0.001) to 6.6% (RR=35%, p=0.001), depending on the number of examiners. The effectiveness of vacuuming to diagnose active infestation was higher than the one of visual inspection, with a prevalence rate of 16.3% (RR=87%, p=0.332). As presented in our study, the vacuuming method was 2.74 to 7.87 times most likely to detect active infestation, thus it could be adopted as a more accurate method to diagnose active pediculosis.

Cognitive Factors Associated to Pediculosis Preventive Behaviors Among Mothers of School-Age Children in Chaldoran County, Iran

BACKGROUND

Despite the improvement of living standards and public health as well as conducting the specific programs based on pediculosis control guidelines, Head Lice Infestation (HLI) is still a worldwide health concern. The purpose of this study was to investigate the cognitive factors associated to school-age children's HLI among mothers in an urban community.

SUBJECTS AND METHODS

In this cross-sectional study, a multi-stage cluster random sample of 619 mothers of students in elementary schools of Chaldoran County, located in North-West of Iran, was recruited to participate in the study. Data were collected applying a set of questionnaires including socio-demographic and cognitive-behavioral factors, including Pediculosis Preventive Behaviors (PPBs), HLI knowledge, threat appraisal, as well as HLI prevention perceived self-efficacy, response efficacy, and perceived collective family efficacy.

RESULTS

Statistically significant differences were found in the children's HLI by their mother's age and performance in PPBs (p-value=0.001). Hierarchical multiple linear regressions were performed with PPBs as outcome variable. According to their natures, the predictors for this outcome variable were classified in two different blocks. Demographic characteristics (p > 0.05), and cognitive constructs (p< 0.001) explained 9% and 21.1% of the observed variance in PPBs, respectively. Pediculosis was found as an epidemic among the students, particularly female students, of Chaldoran County, which call for action by health stakeholders and policymakers.

CONCLUSION

The healthcare providers are recommended to develop HLI prevention programs, within which the mothers and their school-age children as well as school mangers and public places' employers are considered as the core target groups for interventions. Besides PPBs, response efficacy and perceived collective family efficacy to perform the behaviors should be considered as the core categories while designing such prevention programs.

Stigma resulting from head lice infestation: A concept analysis and implications for public health

AIM

The aim of this concept analysis was to examine stigma in the context of head lice, illuminating its components and providing insights for the development of appropriate nursing interventions.

BACKGROUND

Stigma associated with the phenomenon of head lice management is pervasive, promulgating fear and influencing policy and treatment practices. Few studies have examined stigma in this context.

METHOD

The method followed was the Rodgers's evolutionary method.

DATA SOURCES

Health, education, and social sciences databases were searched and yielded 20 articles spanning 1996-2018 used to create a relevant literature review.

RESULTS

Stigma arising from head lice infestation is preceded by an actual or perceived case of head lice, negative perceptions of lice, negative perception of groups or persons with head lice, or being associated with a group or person of lesser status believed to be a carrier of head lice. Defining attributes include marks of infestation, negative and unfair beliefs, and shame. Consequences of stigma are economic costs, social costs, mistreatment, and overtreatment with pediculicides.

CONCLUSION

The concept of stigma in the context of head lice management is multifaceted. Further research is required to understand the magnitude of stigma as well as other factors associated with optimal treatment of children with head lice.

Occlusive versus neurotoxic agents for topical treatment of head lice infestation: A systematic review and meta-analysis

BACKGROUND

Topical occlusive agents, such as petroleum jelly and silicone oils, kill head lice by coating and blocking its excretory system and are unlikely to induce treatment resistance. Although a popular alternative to neurotoxic pediculicides, their efficacy and safety remain unclear.

METHODS

We searched CENTRAL, MEDLINE, HERDIN (from inception to October 31, 2017), and other relevant sources for randomized controlled trials that compared topical occlusive agents with neurotoxic pediculicides to treat patients with head lice infestation. Using Cochrane collaboration methods, we selected studies, assessed risk of bias, and pooled similar studies. We assessed certainty of evidence using GRADEPro.

RESULTS

Seventeen trials (N = 2005) testing occlusive agents met inclusion criteria. Risk of bias was moderate across trials, mainly from lack of blinding of participants and personnel. As a class, occlusive agents may be more pediculicidal than neurotoxic agents (final cure rate, RR 1.20, 95% CI 1.02, 1.41; 16 RCTs, N = 1779; I² = 88%; low certainty of evidence). Post hoc subgroup analysis suggests that this benefit may be limited to synthetic combination occlusive products. Adverse effects, such as skin and eye irritation, are similar between groups (RR 0.65, 95% CI 0.36, 1.17; 15 RCTs, N = 1790; I² = 28%; low certainty of evidence).

CONCLUSIONS

In treating head louse infestation, evidence suggests occlusive agents may be superior to or equally efficacious as neurotoxic pediculicides. Adverse effects are few and minor. Future trials should use appropriate comparators and consider effects of confounders such as neurotoxin resistance. Additionally, optimal occlusive formulation and dosing regimen need to be determined.

First Determination of Pyrethroid Knockdown Resistance Alleles in Human Head Lice (Phthiraptera: Pediculidae) From Chile

The infestation with the human ectoparasite, Pediculus humanus capitis (De Geer), is a common public health problem affecting schoolchildren worldwide. In Chile, the main active ingredients present in the over-the-counter pediculicides contain pyrethroids. Despite the extended use of these products, there is no evidence of the insecticide resistance status of the head lice geographically located in Chile. The most extended resistant mechanism of pyrethroids consists of the target site insensitivity (Kdr) determined by the presence of mutations linked to insecticide-binding sites in the voltage-sensitive sodium channel. T917I is recognized as the main mutation in head lice, and detection is considered to be a biomarker of resistance. The goal of the present study was to detect the presence and distribution of T917I mutation in five geographic locations of Chile. All five geographically selected louse populations had a frequency of pyrethroid resistance genes that ranged from 36 to 77%, and 94.9% of the collected head lice had one or two T917I mutant alleles. Moreover, the frequency of the aggregate resistant alleles was 50.5%. This is the first evidence that head lice in Chile had the mutations commonly associated with the resistance to pyrethroids. Moreover, the overrepresentation of heterozygotes in the studied populations suggests that head lice in Chile are currently under active selective pressure.

Head Lice Recognize and Prefer Head Odor Over Foot and Forearms Odors

Human head lice, Pediculus humanus capitis De Geer (Phthiraptera: Pediculidae), are hematophagous parasites that infest human heads. They are extreme host specialists suggesting a strict selection behavior towards the human head by the parasites. Despite the public health relevance of P. humanus capitis, the role of chemical clues to select the human head is not well known. In the present study, we attempted to find out whether head lice recognize and select the odor of the head over the odor of other parts of the human body. Our results using a two-choice olfactometer demonstrated that head lice were highly attracted by the volatile compounds of the human odor air, but they did not show preference for the volatiles of head compared to the volatiles of other parts of the body (forearm or foot). Conversely, when head lice were exposed in an experimental arena to the whole human odor of different parts of the body, they showed a preferential response to the whole head odor compared with the whole foot or forearm odors. These results suggest that head lice can at short distance of the host, be oriented towards the head odor of the human host in the selection of the scalp environment.

Effect of a New Head Lice Treatment, Abametapir Lotion, 0.74%, on Louse Eggs: A Randomized, Double-Blind Study

Few head lice treatments have demonstrated effectiveness against louse eggs. Abametapir, a metalloproteinase inhibitor, is able to target metalloproteinases critical to egg hatching and louse development. In this double-blind, phase 2 study, 50 subjects aged ≥3 years with active head lice infestation were randomized to receive a single treatment of abametapir lotion, 0.74%, or vehicle (control), applied to scalp and hair for 10 minutes. Ovicidal efficacy was measured by recording the hatch rate of eggs collected from each subject’s hair before and after treatment and incubated for 14 days. With abametapir, 100% of treated eggs remained unhatched compared with 64.0% for vehicle. Accounting for pretreatment hatch rates, the absolute reduction in egg hatching was 92.9% for abametapir versus 42.3% for vehicle (P < .0001). The most frequently reported adverse event was rash (16%). Abametapir lotion, 0.74%, demonstrated significant ovicidal activity against head lice eggs with a single application.

Prevalence of pediculosis and its related factors among primary school girls in the north of Iran

INTRODUCTION

Head lice infestation is one of the main public health problems worldwide and a sanitary, cultural and economic indicator for communities' health. This study aims to estimate the prevalence of head lice infestation among female primary school children in selected districts of Mazandaran Province, Iran.

METHODS

In this cross-sectional study, 3033 female school children were recruited using the consensus method. Head lice infestation was defined as visible adult lice, nymph or egg with the naked eye. Data were described by percent frequency and analyzed using the chi-squared test and multivariate logistic regression models. A p-value less than 0.05 was considered significant.

RESULTS

Prevalence of head lice infestation among female school children was estimated at 7.9%. The adjusted odds ratios (OR) [95% confidence intervals (CI)] for rural residents, low level educated mothers, family size more than five and not combing their hair were 1.96 (1.41-2.78), 2.46 (1.35-4.49), 2.04 (1.12-3.70) and 3.94 (1.73-8.96), respectively. In addition, considering first grade students as a reference group, the ORs (95% CI) for second and third grades were 1.89 (1.18-3.05) and 1.69 (1.05-2.74), respectively.

CONCLUSION

Our study showed that studying in urban schools, low educational level of mothers, grade, family size and no history of regular combing were predictors of head lice infestation.

Cold Atmospheric Pressure Plasma Comb-A Physical Approach for Pediculosis Treatment

Pediculosis, that is the infestation of humans with Pediculus humanus capitis (head lice), poses a worldwide problem that is as old as mankind itself. Over the centuries, man has developed a variety of remedies, all of which have ultimately culminated in the use of chemical agents. Some of these remedies are known to produce successful results. A large portion of the effective remedies used to kill lice and their eggs contain insecticides, but there is an increasing number of reports of head lice populations revealing an increased resistance. This study presents an alternative treatment approach, the efficacy of which is based on physical effects. Cold atmospheric pressure plasmas have successfully shown their formidably wide application range within the field of plasma medicine. This study presents a plasma device in its current stage of development that is engineered as a consumer product to enable an alternative physical and insecticide-free option for the treatment of pediculosis. An efficacy study concerning different developmental stages of P. humanus humanus is presented. P. humanus humanus was chosen as a substitute test organism for P. humanus capitis due to possible laboratory rearing and high anatomic similarity. The study shows how a single stroke of the plasma device over a hair strand (approximately 22 cm in length with a weight of 1.5 g) led to mortality rates of 68.3% (50.0; 79.7) (95% CI) in the juvenile test group, a mortality rate of approx. 67.7% (54.9; 78.8) (95% CI) in the female test group, and approx. 46.7% (28.3; 65.7) (95% CI) in the male test group. When single eggs were introduced directly into the plasma for approx. 1 s, younger eggs (0⁻2 d) showed a higher mortality of 66.7% (42.7; 82.7) than the older (4⁻6 d) eggs, with 16.7% (5.6; 34.7) (CI). Furthermore, the results of a risk assessment of the device are described. The article concludes with necessary handling instructions as well as further developmental steps, derived from the results of the efficacy and the risk assessment study.

Oral ivermectin for the treatment of head lice infestation

PURPOSE

Published literature describing the use of oral ivermectin for the treatment of head lice infestation is reviewed.

SUMMARY

In the United States and globally, head lice infestation, or pediculosis capitis, remains a public health issue with both social and medical implications. Treatment with oral or topical medications is typically required for head lice eradication. Resistance to traditional topical therapies for head lice infestation is increasing, creating a need for consideration of additional treatment options. A growing body of data describing the potential role of oral ivermectin for the treatment or prevention of head lice infestation is available. A literature search identified 5 clinical trials that evaluated safety and/or effectiveness outcomes of oral ivermectin use as an alternative to malathion, other topical prescription medications, and traditional, nonprescription remedies; those studies were conducted in various parts of the world (e.g., Australia, Brazil, Mexico, Egypt) and likely involved varying types and degrees of lice resistance. Clinical research findings to date, while not consistently robust, suggest that oral ivermectin is comparable or superior in effectiveness to other topical treatment options for head lice infestation while being well tolerated and favorably perceived by patients and caretakers.

CONCLUSION

Oral ivermectin is an option for the treatment of head lice infestation, especially in individuals who have experienced a treatment failure. Published evidence from clinical trials indicates that oral ivermectin is as effective as currently available topical treatments.

The efficacy of Australian essential oils for the treatment of head lice infestation in children: A randomised controlled trial

Background

The increase in resistance of head lice to neurotoxic pediculicides and public concern over their safety has led to an increase in alternative treatments, many of which are poorly researched or even untested.

Methods

A multicentre, randomised, assessor‐blind, parallel‐group trial (Trial 1) was conducted to compare the safety and efficacy of a head lice treatment containing Australian eucalyptus oil and Leptospermum petersonii (EO/LP solution; applied thrice with 7‐day intervals between applications) with a neurotoxic treatment containing pyrethrins and piperonyl butoxide (P/PB mousse; applied twice with a 7‐day interval) in children. A single‐blind, open trial (Trial 2) was conducted to assess the efficacy of EO/LP solution following a single application. In addition, skin irritancy and sensitisation tests using EO/LP solution were performed in adults and children. In vitro tests were performed to further assess the ovicidal and pediculicidal efficacy of EO/LP solution.

Results

EO/LP solution was found to be more than twice as effective in curing head lice infestation as P/PB mousse in per‐protocol participants (Trial 1; 83% vs 36%, P < 0.0001), and was also found to be 100% pediculicidal following a single application (Trial 2). Adverse events were limited to transient itching, burning or stinging. Further skin testing with the EO/LP solution reported no irritation or sensitisation in adults, or irritation in children. In vitro exposure of lice and eggs to the EO/LP solution resulted in 100% mortality.

Conclusion

The efficacy, safety and relative ease of use of the EO/LP solution make it a viable alternative in treating head lice.

A Lousy Reason for Surgery Cancellations

Cancellation of surgery has significant adverse impact on patients, health care providers, and their associated facilities. Although head lice infestation has not been shown to be associated with adverse surgical outcomes, it often prompts case cancellation by surgical and anesthesia personnel. The purpose of our study was to evaluate the extent and impact of surgery cancellations due to head lice infestation. In our study, a total of 9 patients were cancelled over a 3-year period. Although there is no direct evidence to show that head lice infestation poses a risk to surgical outcomes, the possibility of underlying secondary bacterial infection at the skin excoriation site is often the concern in these patients. This study offers the first investigation into the impact of head lice infections on operating room cancellations, which may prove to be a potential source of intervention to prevent cancellations.

A Novel Nit Comb Concept Using Ultrasound Actuation: Preclinical Evaluation

Nit combing and removal of head louse, Pediculus humanus capitis De Geer (Anoplura: Pediculidae), eggs is a task made more difficult because "nit combs" vary in efficiency. There is currently no evidence that the binding of the eggshell to the hair can be loosened chemically and few hair treatments improve the slip of the louse eggs along the hair. Ultrasound, applied through the teeth of a nit comb, may facilitate the flow of fluids into the gap between the hair shaft and the tube of fixative holding louse eggs in place to improve lubrication. Ultrasound alone had little effect to initiate sliding, requiring a force of 121.5 ± 23.8 millinewtons (mN) compared with 125.8 ± 18.0 mN without ultrasound, but once the egg started to move it made the process easier. In the presence of a conditioner-like creamy lotion, ultrasound reduced the Peak force required to start movement to 24.3 ± 8.8 mN from 50.4 ± 13.0 mN without ultrasound. In contrast, some head louse treatments made removal of eggs more difficult, requiring approximately twice the Peak force to initiate movement compared with dry hair in the absence of ultrasound. However, following application of ultrasound, the forces required to initiate movement increased for an essential oil product, remained the same for isopropyl myristate and cyclomethicone, and halved for 4% dimeticone lotion. Fixing the nit comb at an estimated angle of 16.5° to the direction of pull gave an optimum effect to improve the removal process when a suitable lubricant was used.

Prevalence of Head Lice Infestation and Its Associated Factors among Primary School Students in Iran: A Systematic Review and Meta-analysis

Objectives

Head lice infestation is one of the most important health problems, generally involving children aged 5–13 years. This study aims to estimate the prevalence of head lice infestation and its associated factors among primary school children using systematic review and meta-analysis methods.

Methods

Different national and international databases were searched for selecting the relevant studies using appropriate keywords, Medical Subject Heading terms, and references. Relevant studies with acceptable quality for meta-analysis were selected having excluded duplicate and irrelevant articles, quality assessment, and application of inclusion/exclusion criteria. With calculating standard errors according to binomial distribution and also considering the Cochrane's Q test as well as I-squared index for heterogeneity, pediculosis prevalence rate was estimated using Stata SE V.11 software.

Results

Forty studies met the inclusion criteria of this review and entered into the meta-analysis including 200,306 individuals. Using a random effect model, the prevalence (95% confidence interval) of head lice infestation among primary school children was estimated as 1.6% (1.2–2.05), 8.8% (7.6–9.9), and 7.4% (6.6–8.2) for boys, girls, and all the students, respectively. The infestation rate was found to be associated with low educational level of parents, long hair, family size, mother's job (housewife), father's job (worker/unemployed), using a common comb, lack of bathrooms in the house, and a low frequency of bathing.

Conclusion

This meta-analysis revealed that the prevalence of head lice infestation among Iranian primary school children is relatively high with more prevalence among girls. We also found that economic, social, cultural, behavioral, and hygienic factors are associated with this infestation.

Alternative Splice in Alternative Lice

Genomic and transcriptomics analyses have revealed human head and body lice to be almost genetically identical; although con-specific, they nevertheless occupy distinct ecological niches and have differing feeding patterns. Most importantly, while head lice are not known to be vector competent, body lice can transmit three serious bacterial diseases; epidemictyphus, trench fever, and relapsing fever. In order to gain insights into the molecular bases for these differences, we analyzed alternative splicing (AS) using next-generation sequencing data for one strain of head lice and one strain of body lice. We identified a total of 3,598 AS events which were head or body lice specific. Exon skipping AS events were overrepresented among both head and body lice, whereas intron retention events were underrepresented in both. However, both the enrichment of exon skipping and the underrepresentation of intron retention are significantly stronger in body lice compared with head lice. Genes containing body louse-specific AS events were found to be significantly enriched for functions associated with development of the nervous system, salivary gland, trachea, and ovarian follicle cells, as well as regulation of transcription. In contrast, no functional categories were overrepresented among genes with head louse-specific AS events. Together, our results constitute the first evidence for transcript pool differences in head and body lice, providing insights into molecular adaptations that enabled human lice to adapt to clothing, and representing a powerful illustration of the pivotal role AS can play in functional adaptation.

Socioeconomic status, family background and other key factors influence the management of head lice in Norway

How head lice infestations are managed by households is an important but generally neglected issue in head lice research. In the present study, we investigate actions taken against head lice by Norwegian households in association with socioeconomic status, family background, school-related variables and other key factors. Repeat questionnaires distributed to caretakers of the same elementary school children during a 2-year period enabled us to study both previous head lice management and any changes in this management through time. Households from 12 schools spanning the main socioeconomic variation found in Norway participated in the study. All students with active head lice infestation were treated in the four investigated periods. Most caretakers used a thorough head lice checking technique and informed others of own infestation. Checking frequency was low as most children were inspected less than monthly. The best determinant of increased checking frequency and thoroughness was personal experience with head lice. The increased awareness, however, seemed to be somewhat short-lived, as there was a decrease in checking frequency and thoroughness within 1 year after infestation. Personal experience with head lice also increased general knowledge related to the parasite. Parents born in developing countries checked their children for head lice more frequently, although less thoroughly, informed fewer contacts when infested, used pediculicides preventively more often and knew less about head lice than parents born in developed countries. Households with highly educated mothers had a lower checking frequency, but their knowledge and willingness to inform others was high. Single parents were more concerned about economic costs and kept children home from school longer while infested than other parents. As head lice management varied among socioeconomic groups and with parental background, differentiated advice should be considered in the control of head lice. The biannual focus on head lice during the 2 years of investigation increased checking thoroughness, while checking frequency remained unchanged. Based on the results, we suggest new head lice management guidelines for health authorities.

Prehistorical Pediculus humanus capitis infestation: quantitative data and low vacuum scanning microscopy

A pre-Columbian Peruvian scalp was examined decades ago by a researcher from the Oswaldo Cruz Foundation. Professor Olympio da Fonseca Filho described nits and adult lice attached to hair shafts and commented about the origin of head lice infestations on mankind. This same scalp was sent to our laboratory and is the subject of the present paper. Analysis showed a massive infestation with nine eggs/cm2 and an impressive number of very well preserved adult lice. The infestation age was roughly estimated as nine months before death based on the distance of nits from the hair root and the medium rate of hair growth. A small traditional textile was associated with the scalp, possibly part of the funerary belongings. Other morphological aspects visualized by low-vacuum scanning electron microscopy are also presented here for adults and nits.

Borrelia recurrentis in head lice, Ethiopia

Since the 1800s, the only known vector of Borrelia recurrentis has been the body louse. In 2011, we found B. recurrentis DNA in 23% of head lice from patients with louse-borne relapsing fever in Ethiopia. Whether head lice can transmit these bacteria from one person to another remains to be determined.

Head lice prevalence among households in Norway: importance of spatial variables and individual and household characteristics

Head lice prevalence varies greatly between and within countries, and more knowledge is needed to approach causes of this variation. In the present study, we investigated head lice prevalence among elementary school students and their households in relation to individual and household characteristics as well as spatial variables. The investigation included households from 5 geographically separated municipalities. Present infestations among household members as well as previous infestations in the household were reported in a questionnaire. In elementary school students prevalence was low (1·63%), but more than one-third of the households (36·43%) had previously experienced pediculosis. Prevalence was higher in elementary school students than in other household members, and highest in third-grade children. Prevalence was also influenced by the school attended, which suggested that interactions between children in the same school are important for head lice transmission. Previous occurrence of head lice in homes also increased the risk of present infestation. Prevalence of previous infestations was higher in households with more children and in more densely populated municipalities, indicating that the density of hosts or groups of hosts influences transmission rates. These results demonstrate that information of hosts' spatial distribution as well as household and individual characteristics is needed to better understand head lice population dynamics.

Typhus and other rickettsioses: emerging infections in Germany

BACKGROUND

Rickettsioses are diseases caused by rickettsiae, obligate intracellular bacteria that are transmitted by arthropods to humans. They cause various types of spotted fever and typhus.

METHODS

A review of the literature is presented along with the authors' own findings.

RESULTS

Six indigenous species of rickettsiae have been found in Germany to date, five of which have been described as human pathogens in other countries. Rickettsia slovaca causes tick-borne lymphadenitis (TIBOLA). Rickettsia helvetica is a known pathogen of nonspecific fever; its role in endocarditis is still under investigation. Rickettsia felis causes so-called flea-borne spotted fever. Rickettsia monacensis and Rickettsia massiliae were recently shown to cause the classical form of tick-borne spotted fever. The sixth indigenous species in Germany, Rickettsia sp. RpA4, has not yet been associated with any human disease. The most important rickettsioses imported to Germany by travelers are African tick bite fever and Mediterranean spotted fever.

CONCLUSIONS

Modern molecular biological techniques have enabled the detection of a number of rickettsial species in Germany. The medical importance of these illnesses in Germany remains to be determined. In travel medicine, imported rickettsioses play a role that should not be underestimated.

Outcomes of the California ban on pharmaceutical lindane: clinical and ecologic impacts

INTRODUCTION

There are increasing concerns over the presence and implications of pharmaceutical agents in water. In 2002, California banned pharmaceutical use of lindane because of concerns about water quality, as lindane treatment for head lice and scabies was found to be a significant factor adversely affecting wastewater quality.

OBJECTIVES

In this article we describe the effects the ban has had on wastewater quality, unintentional exposures, and clinical practice. This is the first time that a pharmaceutical has been outlawed to protect water quality. As such, this ban provides a rare opportunity to evaluate the possible or potential outcomes of future public health interventions aimed at reducing pharmaceutical water contamination.

METHODS

We compiled data on lindane in wastewater treatment plant effluent for several large plants in California and one outside of California. Data on exposures to lindane were obtained from records of the California Poison Control System. We assessed the impact on clinical practice via a survey of 400 pediatricians

RESULTS

Wastewater treatment plant monitoring showed that lindane declined in California after the ban. Similarly, unintentional exposure calls declined. Most physicians were aware of the ban (81%) and had used lindane previously (61%), but they did not notice any difficulties with the ban (78%).

CONCLUSIONS

The California experience suggests that elimination of pharmaceutical lindane produced environmental benefits, was associated with a reduction in reported unintentional exposures, and did not adversely affect head lice and scabies treatment. This ban serves as a model for governing bodies considering limits on the use of lindane or other pharmaceuticals.

Surveillance of insecticide resistance in head lice using biochemical and molecular methods

Treatment of head louse infection is primarily through topical insecticides. However, there is growing evidence of resistance. A representative population sample was tested using biochemical and molecular methods; it was shown that, in Wales, treatments containing pyrethroids are likely to be less effective in controlling head louse infection than those containing organophosphates.