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.

Increased Risk of Surgical Field Contamination from Acute Pre-operative Treatment of Pediculosis Capitis (Lice) Infestation - A Case Report of Two Twin Pediatric Patients

Introduction

Little is known about the perioperative management of Pediculus capitis (lice) infestations, including risk of contamination to the sterile field, whether to delay surgery, and optimal time to treat and/or operate.

Case Report

Two identical twin patients presented for elective in situ percutaneous pinning of chronic slipped capital femoral epiphyses. Active pediculosis capitis was noted intraoperatively by the anesthesia team during the first patient's surgery. Meticulous examination of the sterile field at that time demonstrated no organisms or other sources of contamination. The second patient's surgery was delayed to discuss her case with the infectious disease team. Scant literature exists to guide recommendations. Ultimately, a single permethrin treatment immediately before surgery was recommended and followed by our team. After careful prepping and draping, a louse was observed on the sterile field near the planned pin insertion site. The case was immediately canceled and delayed indefinitely. After two additional treatments over the next 4 days, only eggs (but no active insects) were observed in the patient's hair. We elected to proceed to surgery at that time, which concluded without issue.

Conclusion

The surgical implications of an active lice infestation are numerous. Administration of antiparasitic medication in the immediate pre-operative period causes increased movement in pediculosis capitis, which may increase risk of sterile field contamination. Elective procedures should be postponed to complete multiple rounds of permethrin. In cases of urgent/emergent surgery, or in which treatment delay is unfeasible, foregoing delousing treatment in the immediate pre-operative period may be recommended.

Efficacy and Safety of Neem Oil for the Topical Treatment of Bloodsucking Lice Linognathus stenopsis in Goats under Field Conditions

The aim of the present study was to evaluate the efficacy and safety of neem oil on caprine pediculosis and on kids' growth performances. The neem (Azadirachta indica) belongs to the Meliaceae family, and in Eastern countries it is mainly considered for the insecticidal activities of the kernel oil. The neem seeds contain bioactive principles, such as azadirachtin A, salannin, nimbin, and nimbolide. The trial was carried out on 24 kids, 120 days old, maintained in open yards. Animals were divided in 4 homogeneous groups (n = 6 animals/group) based on age, louse count, body condition score (BCS) and live body weight: Control Group (C, saline NaCl, 0.9%), Neem Group 1 (NO-100, 100 mL of neem oil per 10 kg), Neem Group 2 (NO-200, 200 mL/10 kg), Neem Group 3 (NO-300, 300 mL/10 kg). The treatments were performed by spraying the insecticide on the goat's body. The study lasted 56 days, and weekly, the kids underwent louse count, BCS and body weight determination, and FAMACHA score. Data were analyzed by ANOVA for repeated measures. The species of lice identified was Linognathus stenopsis. Kids belonging to NO-200 and NO-300 showed a stronger reduction of louse count throughout the study (>95%). The daily weight gain recorded was significantly higher (p < 0.05) in NO-300 than C. No differences were found for BCS and FAMACHA scores. The results of this trial showed that the administration of neem oil to control caprine pediculosis caused by sucking lice represents an alternative to synthetic compounds.

First report of classical knockdown resistance (kdr) mutation, L1014F, in human head louse Pediculus humanus capitis (Phthiraptera: Anoplura)

There are at least three known knockdown resistance (kdr) mutations reported globally in the human head louse Pediculus humanus capitis De Geer (Phthiraptera: Anoplura) that are associated with reduced sensitivity to pyrethroids. However, the prevalence of kdr mutation in head lice is not known in the Indian subcontinent. To identify kdr mutations in the Indian head lice population, the genomic region of the voltage-gated sodium channel gene encompassing IIS1-2 linker to IIS6 segments was PCR-amplified and sequenced from P. humanus capitis samples collected from different geographic localities of India. DNA sequencing revealed the presence of four kdr mutations: M827I, T929I, L932F and L1014F. The presence of a classical kdr mutation L1014F, the most widely reported mutation across insect-taxa associated with the kdr-trait, is being reported for the first time in P. humanus capitis.

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.

Prevalence of Pediculosis Among Primary School-Aged Students in Iran: an Updated Comprehensive Systematic Review and Meta-Analysis

In this study, a systematic investigation was performed to estimate the prevalence of head lice infestation, and to determine the factors affecting the prevalence of heterogeneity among primary school-aged children in Iran. A comprehensive search was fulfilled in international databases, including MEDLINE, Scopus, Web of Science, and Embase, to identify the articles on the prevalence of pediculosis. So, all the cross-sectional epidemiological studies evaluating the prevalence of pediculosis were covered without any restrictions. A random-effects model was used to assess the pooled prevalence. A meta-regression method was applied to determine the factors affecting the heterogeneity among the studied population. An analysis was performed on 67 studies with a total sample size of 358,053. The total pooled estimate for the prevalence of pediculosis in boys and girls was 7.52% (95% CI: 6.15-9.03), 1.99% (95% CI: 1.25-2.89), and 8.97% (95% CI: 721-10.91), respectively. The highest and lowest pooled prevalence was in Hormozgan (southern Iran) (29.21%; 95% CI: 8.89-55.34) and Isfahan (Central Iran) (0.69%; 95% CI: 0.59-0.80), respectively. Based on the results of the univariate meta-regression, gender and father's job showed a significant direct association with the prevalence of pediculosis, but the sample size had significant inverse relations with the prevalence of pediculosis. This study demonstrated that pediculosis is a common public health problem affecting school-aged children with a relatively high prevalence in Iran, especially among girls.

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.

Current Use of Ivermectin in Dermatology, Tropical Medicine, and COVID-19: An Update on Pharmacology, Uses, Proven and Varied Proposed Mechanistic Action

Ivermectin is a broad-spectrum antiparasitic drug with anti-inflammatory, anti-viral, anti-bacterial, and anti-tumor effects. In this review, we discuss the history, pharmacology, multimodal actions, indications in dermatology and tropical medicine, therapeutic and prophylactic use of ivermectin in COVID-19, safety, adverse effects, special considerations, and drug interactions of ivermectin.

Dermatoscopy of Infections and Infestations

Dermoscopy is a non-invasive tool for the diagnosis of skin diseases. Entomodermoscopy is a branch of dermoscopy that deals with infections and infestations. The use of dermoscopy for diagnosis of infections and infestations is rapidly increasing as it can provide useful clues related to diagnosis and effectiveness of treatment. It serves as a useful adjunct to microbiological and histopathological examination. In some cases, like scabies dermoscopy can even clinch the diagnosis.

Entodermoscopy Update: A Contemporary Review on Dermoscopy of Cutaneous Infections and Infestations

Infectious cutaneous diseases are very common, especially in certain geographic and tropical regions. Sometimes they may simulate other dermatoses, ordering verification of diagnosis with particular investigations. Dermoscopy is among one of the most important tools readily available in the outpatient setting for the dermatologist to confirm the diagnosis. In this up-to date review, literature concerning the various dermoscopic features of parasitic, viral, dermatophytic and bacterial cutaneous infections is composed. In addition artefacts as well as practical issues in dermoscopy usage are discussed; with the aim to empower dermatologists to promptly and non-invasively diagnose and manage cutaneous infections and infestations.

The Incidence of Scabies and Head Lice and Their Associated Risk Factors among Displaced People in Cham Mishko Camp, Zakho City, Duhok Province, Iraq

This study was conducted to estimate the incidence and the effects of associated risk factors of scabies and head lice on displaced people in Cham Mishko camp, Zakho city, Duhok Province, Iraq. The study included 1300 internally displaced people (IDPs) who visited the dermatology clinic and health care center in Cham Mishko camp from January 2018 to December 2019. Participants' bio-information was collected on special questionnaire form after receiving permission from the camp's health authorities and verbal consent from the participants. Monthly weather data were collected from Duhok Directorate of Meteorology and Seismology. The total rate of ectoparasites was 81.2% (45% for scabies and 36.2% for head lice). Ages from 1-10, 21-30, and 31-40 years showed the highest rates with scabies (48.1%, 46.7% and 46.1%, respectively), while the highest rates of head pediculosis were at ages from 1-10 and 11-20 years (40% and 36.6%, respectively). Scabies rate was slightly higher in males than females (46.6% vs. 43.4%), while the rate of head pediculosis was significantly higher in females than males (58.2% vs. 13.9%). Families with more than ten people showed the highest rates of scabies and head pediculosis (49.5% and 74.5%). Scabies was more common in cold months than in summer while head pediculosis was more common in hot months. The number of scabies and head pediculosis cases increased by 123 and 85 cases, respectively, in 2019. It is inferred that the effects of scabies and head pediculosis in IDPs will be considerable, with a higher carriage rate than other studies in Iraq.

Scabies and Pediculosis in Penitentiary Institutions in Poland-A Study of Ectoparasitoses in Confinement Conditions

BACKGROUND

Scabies (caused by Sarcoptes scabiei var. hominis) and pediculosis (caused by Pediculus humanus) are infectious diseases common in educational institutions and long-term care centres. The aim of the study was to assess the scale of the phenomenon in confinement conditions favouring the spread of these parasitoses.

METHODS

Data on the prevalence of scabies (2001-2015) and pediculosis (2008-2015) in Polish prisoners were provided by the Central Board of Prison Service. The information for the period between 2010 and 2015 in the Lublin Province was obtained from the District Inspectorate of the Prison Service in Lublin. Correlations between the prevalence of scabies and pediculosis and the number of prisoners were analysed, as well as correlations between the number of passes granted to prisoners and the prevalence of scabies and pediculosis in incarcerated individuals.

RESULTS

The prevalence of scabies and pediculosis in Polish prisoners has been estimated at 2.3% and 1.9%, respectively.

CONCLUSIONS

Pediculosis and scabies are still current issues in Polish prisons. Convicts returning from passes and new prisoners should be carefully examined and monitored for the presence of S. scabiei var. hominis and P. humanus invasion. Education of prisoners could be a promising tool in prevention of scabies and pediculosis in correctional settings.

Itching eyes after itching around the head

Objective: To report the occurrence and management of an eyelashes infestation by Phthirus pubis. Methods: A 27-year-old female presented with itching in her right eye and head after she had been traveling in southern Italy five days earlier. Visual acuity (VA) was 20/20 in both eyes. Slit-lamp examination showed bilateral blepharitis. Moreover, mobile insects and eggs attached to the eyelashes were observed. A microbiological study was performed with a Phthirus pubis result. The patient was treated with mechanical dislodging. Results: The resolution of the infection was carried out removing every insect and egg. A vaseline application twice daily for 7 days was necessary to stifle any nits that could remain. Conclusions: The eyelashes pediculosis is frequently caused by Phthirus pubis. Only a minor percentage of the cases are due to Phthirus capitis, but the differential diagnosis is essential: there are Phthirus pubis pediculosis cases due to sexual abuse. A sexual history and screening for other sexually transmitted diseases is warranted.

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.

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.

A field study on the efficacy of ivermectin via subcutaneous route against chewing lice (Bovicola caprae) infestation in naturally infested goats

Caprine pediculosis is an ectoparasitic disease of great concern among goat farmers in India. It may be caused by either sucking lice or chewing lice; the latter one results in severe skin lesions, leading to production loss. This study evaluated the effectiveness of the macrocytic lactone drug, ivermectin, administered via subcutaneous injection, against chewing lice Bovicola (Damalinia) caprae infestation in naturally infested goats. The study was conducted on 20 goats with severe B. caprae infestation. Animals of group A (n = 10) were treated using a single dose of ivermectin (200 µg/kg body weight) subcutaneously and animals of group B (n = 10) underwent placebo therapy using normal saline. The animals were examined on days 0, 3, 7, 14, 21, 28, 42 and 56 for lice counts. There was 100% elimination of lice in all animals of group A and effective protection from re-infection remained at least for 21 days. Considerable improvement in haematological parameters was also observed by day 21. Based on this study, ivermectin injected via a subcutaneous route can be used effectively for the therapeutic and prophylactic management of chewing lice infestation in goats maintained under an extensive grazing system.

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.

Using human head lice to unravel neglect and cause of death

Despite the common association of human lice with abandoned or neglected people, no procedure to assess pediculosis, aimed to detect signs of neglect, exists. Investigating the two most common forms of head louse infestation, regular and severe, we define lice-markers of neglect and develop a protocol and survey form to record and assess pediculosis. The study of head lice from a deceased victim of neglect helped unravel time-length since death, frequency of exposure to neglect and the cause and circumstances related to the death. Nit-clusters are markers of neglect, indicating length and frequency of neglect episodes. In the case study used here that culminated in the death of the victim, sustained abandonment started circa 2 years before discovery. The lice suggested that death was caused by overconsumption of a powerful calcium channel blocker, an antihypertensive, an excess of which in lice food supply (blood) stops oogenesis. Despite hosting thousands of adult females on the hair, lice reproduction stopped and nits were no longer developed or deposited on the hairs at the root end. This short distance of the shaft with no nits provided a time estimation of overdosing of almost 2 months before death.

Head lice predictors and infestation dynamics among primary school children in Norway

BACKGROUND

Health providers need to know which measures to take and children to prioritize in order to decrease costs associated with head lice infestations.

OBJECTIVE

Our aim was to determine the most important predictors for head lice and identify the major drivers of an infestation outbreak in a low-prevalence area.

METHODS

The study was based on three datasets of head lice prevalence (retrospective, point prevalence and prospective approach) from primary school children (ages 6-12) at 12 schools in Oslo, Norway. The tested predictors were siblings with lice, individual and household characteristics as well as class and school affiliation. Self-reported monthly incidences (prospective approach) of head lice were used to evaluate infestation dynamics.

RESULTS

Infested siblings strongly increased the odds of head lice infestation of school children (odds ratio 36, 26 and 7 in the three datasets) whereas having short hair halved the odds. Household characteristics were of minor importance, and class affiliation proved more important than school affiliation. Having head lice in one school term increased the odds of an infestation in the next, but this effect diminished over time. About 97% of all self-reported infestations were noted in two consecutive months or less.

CONCLUSIONS

With the exception of hair length, we have found that individual and household characteristics are of minor importance to predict head lice infestations in a low-prevalence country and that unnoticed transmissions in school classes and families are likely to be the major driver upon outbreaks.

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.

Mercury poisoning in two 13-year-old twin sisters

Mercury (Hg) is a toxic agent that evaporates in room temperature and its inhalation may cause poisoning. Due to the nonspecific symptoms, diagnosis is difficult in special circumstances with no initial history of Hg exposure. We report two such cases of Hg poisoning. The patients were two sisters, presenting with pain in extremities, itchy rashes, sweating, salivation, weakness, and mood changes. They have used a compound that contains mercury, for treatment of pedicullosis three months before admission. This compound was purchased from a herbal shop and was applied locally on the scalps for 2 days. Their urinary mercury concentrations were 50 and 70 mg/L. They were successfully treated by D-penicillamine and gabapentin. In a patient with any kind of bone and joint pain, skin rash erythema and peripheral neuropathy, mercury poisoning should be considered as a differential diagnosis.

Treatment of parasitic skin diseases with dimeticones a new family of compounds with a purely physical mode of action

Epidermal parasitic skin diseases (EPSD) are common in the tropics and sub-tropics. They are caused by mites, lice and other blood-sucking insects. In resource-poor countries they are associated with considerable morbidity. Hitherto, EPSD are treated with insecticides with a neurotoxic mode of action. The efficacy of this treatment is variable, and the development and spread of resistant mites and lice is alarming. A new concept for treating EPSD is presented which is based on the topical application of dimeticones, silicone oils of low viscosity which rapidly kill insects and mites by a physical mode of action. They creep into the respiratory system and block oxygen supply. The physical mode of action makes the development of resistant parasite strains very unlikely. Due to their safety and efficacy, dimeticones are promising candidates for population-based intervention programmes targeted against EPSD in resource-poor settings.

The use of essential oils in veterinary ectoparasite control: a review

There is a growing body of evidence indicating the potential value of essential oils as control agents against a range of arthropod ectoparasites, particularly lice, mites and ticks. Toxicity has been demonstrated following immersion and physical contact with treated surfaces, as well as after exposure to the vapour of these oils; the last of these factors implies that there is a neurotoxic, rather than simply a mechanical, pathway in their mode of action. However, the volatile nature of essential oils suggests that their residual activity is likely to be short-lived. A possible advantage of essential oils over conventional ectoparasite treatments may refer to their reported ovicidal efficacy, although it is unclear whether this results from neurotoxicity or mechanical suffocation. There are many difficulties in comparing the findings of existing studies of essential oil toxicity. One major issue is the wide variation among batches in the relative concentrations of oil constituents. A second issue concerns the fact that many experimental designs make it difficult to confirm that the effect seen is attributable to the oil; in many cases inappropriate controls mean that the effects of the excipient on mortality cannot be distinguished. Hence, it is important that an excipient-only control is always included in these bioassays. Furthermore, in direct contact assays, when attempting to identify the toxicity pathway of the essential oil tested, it is important to include a hydrophobic control. Without this, it is impossible to distinguish simple mechanical effects from neurological or other cellular toxicity. The use of essential oils in the control of veterinary ectoparasites is an area which holds considerable potential for the future and research into their use is still at an early stage. More extensive field trials, the standardization of components, the standardization of extraction, the standardization of good experimental design, mammalian toxicology profiling and excipient development, as well as further investigation into the residual activities and shelf-lives of these oils are all required to allow the full realization of their potential.

Control of the chewing louse Bovicola (Werneckiella) ocellatus in donkeys, using essential oils

Infestations by lice can be a significant clinical and welfare issue in the management of large animals. The limited range of commercial pediculicides available and the development of resistance have led to the need to explore alternative louse management approaches. The results of in vitro and in vivo trials undertaken to control populations of the donkey chewing louse, Bovicola ocellatus (Piaget) (Phthiraptera: Trichodectidae) using the essential oils of tea tree (Melaleuca alternifolia) and lavender (Lavandula angustifolia) are reported here. Results of contact and vapour bioassays showed that 5% (v/v) tea tree and lavender oils resulted in > 80% louse mortality after 2 h of exposure. On farms, separate groups of 10 donkeys sprayed with 5% (v/v) tea tree and lavender oil as part of their usual grooming regime showed significant reductions in louse numbers compared with a control group (0.2% polysorbate 80 in water). These findings indicate that tea tree and lavender essential oils can provide clinically useful levels of control of B. ocellatus when used as part of a grooming routine and suggest that with further development could form the basis of an easy to apply and valuable component of a louse management programme for donkeys.

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.

Soya oil-based shampoo superior to 0.5% permethrin lotion for head louse infestation

BACKGROUND

This was a randomized, assessor-blind, controlled comparison of a soya oil- based medical device shampoo with a medicinal permethrin lotion in an alcohol vehicle for treatment of head louse infestation to generate data suitable for a regulatory submission to achieve reimbursable status for the shampoo product.

METHODS

We treated 91 children and adults, divided between two sites, on two occasions 9 days apart. Participants washed their hair and towel-dried it before treatment. The shampoo was used twice for 30 minutes each time. The lotion was used for 30 minutes followed by rinsing. Assessments were made by dry detection combing on days 2, 9, 11, and 14 after the first treatment. According to present knowledge, this combing technique does not influence the overall head louse populations or outcome of treatment.

RESULTS

The soya oil shampoo was significantly (P < 0.01) more effective than the lotion for both intention to treat (62.2% versus 34.8% successful treatment) and per-protocol (74.3% versus 36.8% success) groups. Post-treatment assessments showed the necessity for repeat treatment, but that a 9-day interval was too long because if eggs hatched after the first treatment, the lice could grow old enough to lay eggs before the second treatment.

CONCLUSION

The soya oil-based shampoo was more effective than the permethrin lotion, more cosmetically acceptable, and less irritant.

Infestation status of head louse and treatment with lindane shampoo in children of primary school and kindergarten in Chinju-shi, Kyongsangnam-do, Korea

The infestation status of head louse among children attending primary schools and kindergartens in Chinju-shi, Kyongsangnam-do, Korea, was investigated between June and July 1999. Out of 2,288 children examined, 3.9% of boys (48/1,242) and 23.5% of girls (246/1,046) were infested with nits or adult/nymphs of lice. The effectiveness of lindane shampoo (1% gamma benzene hexachloride solution) was evaluated after one or two time applications to all the children infested. The negative conversion rate of pediculosis was 93.5%. Effective control measures are needed to control and prevent such ectoparasite infestation amongst children.