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

Effectiveness and chemical insights: Exploring interactions between nanomicelles and monoterpenoids for head lice treatment

This study evaluates the pediculicidal activity of nanoformulations containing different binary essential oil component mixtures (eugenol:linalool, 1,8 -cineole:linalool, and eugenol:thymol) using immersion bioassays. These have allowed us to evaluate the knockdown time affecting 50% of the individuals (KT50). In addition, the type of interaction between the components in each mixture was established in terms of the combination index (IC). The KT50 values were 6.07; 8.83; 7.17 and 27.23 h for linalool, 1,8 -cineole, eugenol, and thymol, respectively. For the eugenol:linalool mixtures, the efficacy was lower or equal to that obtained for the nanoformulations of the pure compounds, with values of KT50 about 13.33, 8.16 and 6.71 h for mixtures with ratios 3:1, 1:1 and 1:3, respectively. These mixtures present IC > 1, evidencing antagonistic interaction, which is enhanced with eugenol content. In the case of the binary mixtures of 1,8 -cineole: linalool, KT50 values were similar to those obtained for eugenol:linalool mixtures with similar ratios. In this case, IC assumes values close to unity, suggesting additive interactions independently of the mixture composition. On the other side, mixtures of eugenol:thymol with 1:1 and 1:3 ratios showed values of 9.40 and 32.93 h, while the mixture with a 3:1 ratio showed the greatest effectiveness (KT50 of 4.42 h). Eugenol:thymol mixtures show synergistic interaction (IC < 1) for combinations 3:1 and 1:1, while no interaction was observed for 1:3 combination. This indicates that eugenol enhances thymol activity. These results must be considered an important step forward to the development of effective pediculicidal nanoformulations based on botanical compounds.

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

Background

Head louse infestation, pediculosis, is a serious health problem worldwide. Infected children usually suffer from itching, allergies, and secondary infections besides psychological disorders such as depression and lack of self-confidence leading to school failure. This study aimed to investigate the status of pediculosis and its determinant factors among schoolchildren in Amol City, Northern Iran.

Methods

This study included 228 schools frequented by about 20017 students. Pediculosis was determined by careful examination of students' hair on the scalp, back of the neck, and around the ears. The diagnosis was based on observation of live adults, nymphs, and nits. A questionnaire was used to record the personal and demographic characteristics of participants.

Results

This study revealed that the prevalence of pediculosis among schoolchildren during all schooling seasons (autumn, winter, and spring) correlated with sex: the prevalence being higher among girls than boys (p= 0.00). In addition, the highest rates of pediculosis occurred during the autumn season (p= 0.00). The public schools accommodated higher numbers of louse-infected students than the private ones (p= 0.00). While head louse occurred at higher frequencies in long hair over the schooling year, dandruff had anti-louse effects (p= 0.00) during cold seasons, autumn, and winter. Socioeconomic status and educational level of parents played determinant roles in head louse prevalence (p= 0.00). Schoolchildren coming from socioeconomically well-situated families had lower rates of head louse infestation.

Conclusion

Our results showed that head pediculosis was a serious health problem among schoolchildren in Amol city and its prevalence and severity tended to be multifactorial.

The effect of educational intervention on efficacy of 1% permethrin shampoo and 4% dimeticone lotion to treat head lice infestation using propensity score matching (PSM)

BACKGROUND

Head lice are a main public health problem and the most important human ectoparasites and the use of pediculicides is the most common way to control it. One of the possible causes of treatment failure is the lack of improper application of pediculicide. The aim of this study was to assess the effect of education on efficacy of 1% permethrin or 4% dimeticone lotion to treat head lice infestation.

METHODS

This quasi-experimental study included 100 individuals with head lice infestation from comprehensive urban health centers in Ardabil as the intervention group, and 400 individuals from East Azerbaijan and West Azerbaijan provinces as the control group, from April to March 2019. The data collection tools included a demographic questionnaire and an examination recording sheet, which documented the presence of adult lice or nits. Due to the inability to perform random assignment and control for numerous observed covariates, propensity score matching (PSM) was used.

RESULTS

The outcome of treatment included elimination of head lice infestation on is 7, and in the case of recurrence, it was considered on days 14 and 30 after treatment. The results showed that the educational intervention program had a significant positive effect on the efficacy of both treatments. The likelihood of improvement was approximately three times greater in the intervention group compared to the control group.

CONCLUSION

Participants who received the training intervention (OR = 3.29; CI 95%: 2.21-4.88) were more likely to have a successful treatment than control group. In the case of providing proper training on the use of pediculicides and observing hygiene tips to patients with pediculosis, could help to successful treatment of pediculosis.

Comparing the efficacy of three methods of permethrin application in pediculosis capitis: A randomized clinical trial

BACKGROUND

Pediculosis capitis, also known as head lice, is a common problem that affects individuals of different socio-economic backgrounds. Permethrin is generally considered the first-line treatment option for head lice.

AIMS

The objective of this study was to evaluate and compare the therapeutic effects of three different methods of permethrin treatment for head lice.

METHOD

A parallel, randomized clinical trial was conducted on 157 patients with head lice. The participants underwent eye examination and dry combing by a trained professional. The subjects were randomly divided into three groups and treated with one of the three methods of permethrin application: permethrin shampoo for 10 min, permethrin shampoo for 1 h, or permethrin cream for 10 min on a weekly basis for 3 weeks.

RESULTS

Of the 157 participants, 154 completed the study. The group treated with permethrin shampoo for 1 h had the shortest average time for eradication of lice at 1.226 ± 0.422 weeks, which was significantly lower than the other two groups. Additionally, the 1-h permethrin shampoo group had the lowest time for scalp itching of 2.15 ± 0.632 weeks, which was significantly lower than the other two groups. Moreover, the rate of lice eradication in the first week was significantly higher in the 1-h permethrin shampoo group.

CONCLUSION

The results of this study suggest that the use of 1% permethrin shampoo for 1 h is more effective in eradicating head lice within the first week of treatment and in relieving scalp itching during the second week.

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.

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

BACKGROUND

Head louse infestation is an important public health problem, and expanding resistance to permethrin is a major challenge to its control. The mapping and detection of pyrethroid resistance are essential to the development of appropriate treatments and ensure the effectiveness of current measures. The aim of this study was to present the phenotypic and genotypic basis of permethrin resistance and identify knockdown resistance (kdr) mutations in head louse populations in northwestern Iran.

METHODS

Adult head lice were collected from 1059 infested girls in Ardebil, East Azerbaijan, West Azerbaijan and Zanjan Provinces, northwestern Iran. The toxicity of permethrin and the possible synergistic effect of piperonyl butoxide (PBO) on this toxicity were assessed using bioassays. Fragments of voltage-sensitive sodium channels (vssc) and cytochrome b (cytb) genes were amplified and analyzed for the detection of knockdown resistance (kdr) mutations and mitochondrial groups. Moreover, genotypes of the two hot spot regions of the vssc gene were determined by melting curve analysis of amplicons.

RESULTS

A total of 1450 adult head lice were collected during 2016-2021. Live lice were exposed to a dose of 1% permethrin for 12 h, and the median lethal time (LT₅₀) and time to achieve 90% mortality (LT₉₀) were determined to be 6 and 14.8 h, respectively. Topical application of 2 and 16 ng permethrin per louse resulted in 25% and 42.11% mortality, respectively. Pre-exposure of samples to 3% piperonyl butoxide had no synergistic effect on the effects of permethrin. Analysis of the 774-bp vssc gene fragment showed the presence of the M815I, T917I and L920F mutations, wild-type and T917I mutation, in 91.6%, 4.2% and 4.2% of samples, respectively. Investigation of the mitochondrial cytb gene demonstrated the predominance of clade B. The frequency of domain II segment 4 (S4)-S5 kdr genotypes in mitochondrial groups was identical, and heterozygotes were present in 93.5% of samples. A significant difference was detected in the frequency of domain IIS1-S3 kdr genotypes, and the frequency of resistant alleles and heterozygotes was higher in clade B than in clade A.

CONCLUSIONS

The presence of kdr mutations in the vssc gene and the non-synergist effect of PBO indicate that pyrethroid target site insensitivity is the main resistance mechanism. This phenomenon and the high frequency of resistant alleles necessitate that new pediculosis management programs be developed. Further studies need to be conducted to identify all factors contributing this resistance and to develop alternative pediculicides.

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.

Pyrethroid-linked resistance allelic mutations by molecular analysis in wild human head louse (Phthiraptera: Pediculidae) populations from schoolgirls of South Iran

Background

Human head louse, Pediculus humanus capitis De Geer, 1767 (Anoplura: Pediculidae), is one of the most frequent ectoparasites infesting Homo sapiens worldwide. Reduced sensitivity to treatment due to genetic mutations, in particular knockdown resistance (kdr) (or target site insensitivity) allele, has led to this infestation prevalence. Molecular characterization of this resistance has a crucial impact on selecting appropriate treatment protocol. The aim of this study was to investigate kdr gene mutations on voltage-sensitive sodium channel (VSSC) among wild head lice samples from Fars province, southern Iran.

Methods

Head lice were collected using plastic detection combs on girls enrolled in public schools from 10 counties in Fars province. The specimens were screened in 10 pools (each pool per county containing 35 specimens), with three pools (30%) being positive. Following species identification with valid entomological keys, 350 (68%) out of 514 randomly collected adult head lice were analyzed after their somatic genomic DNA extraction using Sinaclon kit. Samples were investigated by polymerase chain reactions (PCR), and the amplicon was subsequently sequenced.

Results

Sequence analysis showed that the sodium channel genes in the pooled ectoparasites had two intron and three exon regions. Single (L840F), double (I836L, E837K), and triple novel point mutations (V875L, Q876P, S879V); the last involving two concomitant allelic substitutions; were discovered in the second and third exon regions of head louse DNA on chromosome II from three (30%) counties. Other exon or intron regions remained non-mutated from the remaining seven counties.

Conclusions

The detection of six amino acid substitutions from 30% of examined head lice among infested schoolgirls reveal that mutants are minutely developing. These findings provide further incentive to recapitulate the legitimacy of current control measures and resolve dynamics of resistance in human head louse populations.

Impact of a health educational interventional program on reducing the head lice infestation among pupils in an elementary school of a sub-tropical region: a quasi-experimental study

BACKGROUND

Pediculosis is an important social challenge that can be caused by human head louse, Pediculus humanus capitis. This infestation is cosmopolitan, especially in countries with low hygiene and sanitation. Regular health education classes for students and their parents are required to reduce this infestation in schools and families. This study aimed to evaluate the impact of a health education intervention program on reducing head lice among pupils of an elementary school.

METHODS

In a quasi-experimental study, a total of 880 elementary school girls were screened for pediculosis in (2017-2018). The prevalence of pediculosis follow-up continued monthly until the end of the school year after a two months educational intervention course. Visual inspection was applied for initial diagnosis of infection. The suspected cases were confirmed by wood lamp and potassium hydroxide (KOH) microscopic examination. Also eight questions about diagnostic, epidemiology, treatment and prevention were answered in a questionnaire by 50 volunteer parents before and after the training intervention course, to evaluate their general knowledge and measure the effectiveness of learning. All data were statistically analyzed using SPSS software (version 20.0, SPSS, Inc., Chicago, IL, USA). McNemar's test was also applied to investigate the prevalence rate before and after the intervention. A p -value of less than 0.05 was considered as statistically significant.

RESULTS

At the beginning of study, pre-intervention prevalence of pediculosis among pupils was 8.4% (49/594). The mean age in all pupils was 9.86 ± 1.83 years old and the most infestation was shown in fourth-grade students with 10 years old. Analysis of statistics demonstrated a significant difference between having infestation and the number of members in the families. Post-intervention phase led to a decreased prevalence of pediculosis in pupils to 3% (8/594) (p-value < 0.05). Based on statistical analysis of questions before and after the training in the questionnaire, a significant increase of parental knowledge was observed on the prevention program of pediculosis (p-value < 0.001).

CONCLUSION

The prevalence of pediculosis was significantly reduced following the educational interventions in the school. The applied interventions may be implemented in other residual centers to get rid of this important infestation.

Pediculicidal Activity of Foeniculum vulgare Essential Oil in Treatment of Pediculus capitis as a Public Health Problem

Background

Pediculosis, caused by Pediculus spp is an important public health problem in urban and rural areas around the world. Natural compounds such as plant essential oils (EOs) have been suggested as a potential alternative for insect pest control recently. The purpose of this study was to investigate the toxicity of Foeniculum vulgare essential oil against the head louse, Pediculus capitis under laboratory conditions.

Methods

Fennel essential oil components were analyzed using GC-mass apparatus. Immersion and contact filter paper bioassays were used to evaluate fennel essential oil toxicity at the two-fold concentrations of 2.5, 5, 10, 20, and 40% against nit and nymph/adult stages of the head louse.

Results

Trans-anethole, α-Thujone, and limonene, which consisted of 76.08%, 10.37%, and 5.34% were the most components of fennel oil respectively. The LC₅₀ values for the adult /nymphs were 11.5, 6.4, 3.9, 3.1 and 2.5% and LC₉₉ values were 29.5, 15.2, 12.8, 10.8, and 7.4% at 10, 20, 30, 45 and 60 minutes after exposure respectively. The lethal times (LT₅₀) for adults/nymphs were 5.2, 8.1, 9.5, 20.5, and 45.8 minutes and LT₉₉ were 138.6, 91.3, 23.8, 21.7, and 13.9 minutes in the concentrations of 2.5, 5, 10, 20 and 40%, respectively. LC₅₀ and LC₉₉ values were 2.32% and 7.36% after 5 days for the eggs.

Conclusion

Fennel essential oil at the concentration of 15% after 20min is suggested to develop as an appropriate formulation to evaluate in clinical trials.

Epidemiological Study of Pediculosis among Primary School Children in Sulaimani Governorate, Kurdistan Region of Iraq

Background

Pediculosis is a common parasitic public health issue. Many socio-demographic and economic factors affect the pattern and prevalence of pediculosis. It is widely spread among pupils, particularly those in elementary schools. This study aimed to determine the prevalence of Pediculus capitis infestation and its related risk factors in primary school children in Sulaimani Governorate, Kurdistan Region of Iraq.

Methods

This is a cross-sectional study, overall, 2064 primary school children (aged 5-14 years) during the period from October 2019 to February 2020 were randomly examined for the presence of any stage of Pediculosis capitis in both urban and suburban areas. The schools were selected by multistage sampling methods. A questionnaire was sent to the parents to get consent and fill in for every single pupil. The results were computed using the chi-square test and logistic regression analysis.

Results

The overall prevalence of head lice infestation was (9.16%). The study found a significant association of Pediculosis capitis infestation with gender, parents' education level, mother's employment, number of siblings, and previous infestation. The older age of children (≥12 years old) and the higher-grade pupils (4^th to 6^th class) were more infested.

Conclusion

Head lice remain a health problem for school children. It needs collaboration of many sectors for decreasing and early detection and treatment in both urban and suburban areas since they have a close rate of infestation.

Heavy head lice infestation in an adolescent girl following benzodiazepine poisoning

Loss of consciousness (LOC) is one of the most common causes of emergency department (ED) visits. It may be due to intoxication or hypoglycemia. We present a 15-year-old girl who was referred with heavy head lice and LOC to the ED in the north of Iran.

Explaining the Determinants of Pediculosis Control and Prevention: A Qualitative Study in Southern Iran

In many regions of the world, human head lice infestations caused by Pediculus capitis are a major health concern among school-aged children. This study was carried out to explain variables influencing pediculosis prevention and control from the perspective of parents and teachers of female elementary school pupils, as well as healthcare practitioners in Bandar Abbas, Iran. Participants in this qualitative study included 23 participants, including parents and teachers of primary school girls, as well as healthcare practitioners. Purposive sampling was employed and sustained until data saturation was reached. Data was acquired through in-depth interviews and evaluated using content analysis in the form of constant comparison. To assess the quality of the outcomes, Lincoln and Guba’s criteria were used. The data were extracted into 2 primary categories, including challenges and facilitators to controlling pediculosis, each with several subcategories as follows: 1) economic-political aspects; 2) family factors; 3) social-cultural elements; 4) personal and mental issues; 5) geographical position of the investigated region; 6) school and education factors; and 7) factors related to medications and therapy. There were 2 types of facilitators: 1) informative factors and 2) social-cultural variables. According to the findings, pediculosis prevention, control, and treatment necessitate multifaceted and multi-level intervention. Some solutions must be addressed at the personal-psychological, familial, political-economic, geographical, and informational levels, as well as school-related concerns, social stigma elimination, and evaluation of cultural components of the issue at the social level.

Frequency of pyrethroid resistance in human head louse treatment: systematic review and meta-analysis

Head lice (Pediculus humanus capitis) are one of the most common insects causing infestations in humans worldwide, and infestation is associated with adverse socio-economic and public health effects. The development of genetic insensitivity (e.g., target site insensitivity = knockdown resistance or kdr) to topical insecticides has impaired effective treatment. Therefore, this study was undertaken to review and meta-analyze the frequency of pyrethroid resistance in treated head louse populations from the beginning of 2000 to the end of June 2021 worldwide. In order to accomplish this, all English language articles published over this period were extracted and reviewed. Statistical analyses of data were performed using fixed and random effect model tests in meta-analysis, Cochrane, meta-regression and I2 index. A total of 24 articles from an initial sample size of 5033 were accepted into this systematic review. The mean frequency of pyrethroid resistance was estimated to be 76.9%. In collected resistant lice, 64.4% were homozygote and 30.3% were heterozygote resistant. Globally, four countries (Australia, England, Israel, and Turkey) have 100% kdr gene frequencies, likely resulting in the ineffectiveness of pyrethrin- and pyrethroid-based pediculicides. The highest resistance recorded in these studies was against permethrin. This study shows that pyrethroid resistance is found at relatively high frequencies in many countries. As a result, treatment with current insecticides may not be effective and is likely the cause of increased levels of infestations. It is recommended that resistance status be evaluated prior to insecticide treatment, to increase efficacy.

Molecular Monitoring of Knockdown Resistance in Head Louse (Phthiraptera: Pediculidae) Populations in Iran

Knockdown resistance (kdr) is a common mechanism of insecticide resistance in head lice to the conventionally used pyrethroid pediculosis and can be the result of various amino acid substitutions within the voltage-sensitive sodium channel (VSSC). In this study, 54 sequences from varied specimens were investigated to monitor well-known resistance mutations and probable new mutations. The Pediculus humanus capitis de Geer specimens were collected from 13 provinces in Iran. The specimens were stored in 70% ethanol until DNA extraction and PCR amplification of ~900-bp fragment of VSSC. The sequences were analyzed using different bioinformatics software for the detection of well-known kdr substitutions and additional mutations potentially associated with kdr resistance in head lice. There were six new and an old (haplotype I) kdr haplotypes within the Iranian head louse population. K794E, F815I, and N818D amino acid substitutions were reported for the first time. The P813H mutation was the most prevalent amino acid substitution in eight provinces. Among 53 sequences, 26 (49%) were homozygous susceptible, and 27 (51%) were heterozygotes. Thus, 51% of the head lice collected in Iran harbored only the P813H allele. The exact test for the Hardy-Weinberg (H-W) equilibrium showed that genotype frequencies differed significantly from the expectation in East-Azerbaijan and Tehran provinces. Moreover, these populations had an inbreeding coefficient (Fis) <0, indicating the excess of heterozygotes. This observation suggests that the populations of head lice from Iran are currently under active selective pressure. For the rest of the populations, H-W equilibrium and the expectations were significantly in harmony. The results of the current study highlight molecular techniques in the accurate detection of resistance genotypes before their establishment within the head louse population. Accurate detection of resistant genotypes seems to be helpful in decision-making on lice control programs and resistance monitoring and management.

Children’s Perception Scale of Head Lice Infestation (CPS-HLI): Design and Psychometrics

Background: Pediculosis is a common ectoparasitic infestation that involves especially the skin of children worldwide. Studying the children’s perception of the disease’s risk factors, the effectiveness of personal preventive measures, and its implications for their health could be a major leap forward in health promotion activities. Objectives: This study aimed to develop and evaluate the psychometric properties of the Children’s Perception Scale of Head Lice Infestation (CPS-HLI) and its initial feasibility assessment for use on Iranian and possibly other elementary school children. Methods: The scale’s items were retained based on an extensive literature search and classified into the underlying constructs of the extended health belief model (EHBM). An expert panel endorsed the qualitative content and face validity of the preliminary draft, and 47 items remained for quantitative validity testing on a sample of 362 elementary school students in the city of Paveh, West of Iran. Explanatory and confirmatory factor analyses (EFA and CFA) were employed to test the content and structural validity of the constructed instrument. Cronbach's alpha and intra-class correlation coefficients were calculated to assess the internal consistency and reliability of the scale. Results: The values of Lawshe's content validity index (0.90) and content validity ratio (0.77), the subscales’ Cronbach's alpha (0.59), and intra-class correlation (0.72) coefficients confirmed plausible internal consistency of the scale. The values of root mean square error of approximation (RMSEA) (< 0.08 with χ2 < 0.05), Tucker-Lewis index (TLI), and comparative fit index (CFI) > 0.9 approved the applied statistical model’s goodness of fit. The ranges of Kaiser-Meyer-Olkin (KMO) measure of sampling adequacy for the underlying subscales (0.49 - 0.74) and the statistically significant result of Bartlett’s test of sphericity (P < 0.001) confirmed the patterned relationship among the constructed scale’s items. The principal component analysis that was performed using STATA favored the 11-factor solution. Conclusions: The study findings support the construct validity of CPS-HLI for use in studies on children’s perception of head lice infestation risk factors, the effectiveness of personal preventive measures, and the disease implications for their health and well-being. Further cross-cultural and cross-national validation studies are recommended for using the instrument in a wider range of populations and settings.

Comparative efficacy and safety of interventions for treating head lice: a protocol for systematic review and network meta-analysis

Background

Head lice infestation is a major public health problem around the globe. Its treatment is challenging due to product failures resulting from rapidly emerging resistance to existing treatments, incorrect treatment applications and misdiagnosis. Various head lice treatments with different mechanism of action have been developed and explored over the years, with limited report on systematic assessments of their efficacy and safety. This work aims to present a robust evidence summarising the interventions used in head lice.

Method

This is a systematic review and network meta-analysis which will be reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement for network meta-analyses. Selected databases, including PubMed, Embase, MEDLINE, Web of Science, CINAHL and Cochrane Central Register of Controlled Trials will be systematically searched for randomised controlled trials exploring head lice treatments. Searches will be limited to trials published in English from database inception till 2021. Grey literature will be identified through Open Grey, AHRQ, Grey Literature Report, Grey Matters, ClinicalTrials.gov, WHO International Clinical Trials Registry and International Standard Randomised Controlled Trials Number registry. Additional studies will be sought from reference lists of included studies. Study screening, selection, data extraction and assessment of methodological quality will be undertaken by two independent reviewers, with disagreements resolved via a third reviewer. The primary outcome measure is the relative risk of cure at 7 and 14 days postinitial treatment. Secondary outcome measures may include adverse drug events, ovicidal activity, treatment compliance and acceptability, and reinfestation. Information from direct and indirect evidence will be used to generate the effect sizes (relative risk) to compare the efficacy and safety of individual head lice treatments against a common comparator (placebo and/or permethrin). Risk of bias assessment will be undertaken by two independent reviewers using the Cochrane Risk of Bias tool and the certainty of evidence assessed using the Grading of Recommendations, Assessment, Development and Evaluations guideline for network meta-analysis. All quantitative analyses will be conducted using STATA V.16.

Discussion

The evidence generated from this systematic review and meta-analysis is intended for use in evidence-driven treatment of head lice infestations and will be instrumental in informing health professionals, public health practitioners and policy-makers.

PROSPERO registration number

CRD42017073375.

Concurrent anemia and stunting among schoolchildren in Wonago district in southern Ethiopia: a cross-sectional multilevel analysis

BACKGROUND

Even if many schoolchildren in Ethiopia are anemic and stunted, few have studied the co-existence of anemia and stunting among schoolchildren in Ethiopia. In addition, multilevel analysis to explore the variation in prevalence of concurrent anemia and stunting (CAS) across schools and classes is rarely applied. Thus, we aimed to assess the prevalence and risk factors of CAS at the individual, household, and school level among schoolchildren in southern Ethiopia.

METHODS

We recruited 864 students aged 7-14 years from the Wonago district in southern Ethiopia using a three-stage random sampling, assigning four schools to level one, 24 classes to level two. We then randomly selected 36 children from each class, and recorded their weight, height, haemoglobin, intestinal helminthic infections, hygienic practices, dietary practices, household food insecurity, and socio-demographic information. A multivariate, multilevel logistic regression model was applied to detect potential risk factors for CAS.

RESULTS

The prevalence of CAS was 10.5% (85/810) among schoolchildren, which increased with age in years (adjusted odds ratio [aOR] 1.39 [95% confidence interval 1.13, 1.71, P = 0.002]) and among children who always did not wash their hands with soap after use of latrine (aOR 4.30 [1.21, 15.3, P = 0.02]). Children who walked barefoot (aOR 10.4 [2.77, 39.1, P = 0.001]), were infected with Trichuris trichiura (aOR 1.74 [1.05, 2.88, P = 0.03]), or had head lice infestation (aOR 1.71 [1.01, 2.92, P = 0.04]) had higher CAS prevalence. Prevalence rates of CAS were low in those using treated drinking water (aOR 0.32 [95% CI 0.11, 0.97, P = 0.04]). Most of the risk factors for CAS were identified at the individual level. The clustering effect measured by the intra-cluster correlation coefficient was 6.8% at school level and 19% at class.

CONCLUSION

CAS prevalence is a moderate public health problem among schoolchildren in southern Ethiopia and varies across classes and schools. After controlling for clustering effects at the school and class levels, we found an association between CAS and increasing age, not always washing hands with soap after using latrine, walking barefoot, and T. trichiura infection. Using treated water for drinking was found to have a protective effect against CAS. Thus, educating children on personal hygiene and provision of safe drinking water could reduce the CAS burden in schoolchildren in rural areas of southern Ethiopia.

Assessment of the prevalence of pediculosis capitis and related effective features among primary schoolchildren in Ahvaz County, Southwest of Iran

The present research was carried out to investigate the prevalence of head lice and related effective features among students in primary schools of Ahvaz County; Iran; to suitable training programs via improve the health promotion of the students in this county during winter 2016 and spring 2017. The sample size was 5930 students that was determined by using a single population proportion formula. In this analytical-descriptive study, samples were selected by a multistep, classification random sampling strategy. The data was collected in two parts, a carefully visual examination of the hair and scalp with head lice comb, and an interview to complete a questionnaire about epidemiologic factors. The collected data was evaluated using SPSS software, version 22. These data were compared using a Chi-square analysis, and a p value of less than 0.05 was considered to be significant. The overall head lice infestation rate in the studied population was 26.3%. The prevalence rate was 15.2% in the boys and 37.9% in the girls, while the rate of infestation was 25.1% in the urban areas and 36.9% in the villages. Also, a statistical significant relationship was observed between Pediculosis capitis and gender, geographical area, type of home, access to tap water, hygiene bath at home, bath times per week, the number of family individuals, sleeping in the common bedroom, use common bedding, daily comb, use common comb, use common towel, use common scarf, history of infestation, presence health educator in school, access to primary health services, knowledge about head lice, infestation in the family, performing personal hygiene, itching on the head and hair style, length, density, and color. The high prevalence of head lice among students in the majority of primary schools in Ahvaz County is attributable to inadequate access to health educators, sanitation facilities, inattention to personal health, and other related factors. The controlling program must be done more efficiently to prevent the prevalence of head lice infestation. It is suggested that the people's knowledge and attitude about biology, clinical presentation, prevention, and treatment strategies of pediculosis capitis should be improved.

Comparative efficacy of permethrin 1%, lindane 1%, and dimeticone 4% for the treatment of head louse infestation in Iran

Pediculosis capitis occurs worldwide. Children in the age group of 5-13 years are the ordinary victims. Population-based studies show that the prevalence of pediculosis is 1.6-13.4% in various regions of Iran. In this observer-blinded trial, we conducted a study to evaluate the comparative efficacy and safety of permethrin 1% and lindane 1% shampoos and dimeticone 4% lotion to cure head lice infestation in children aged 7-13 years in female primary schools in Ahvaz City, Iran. Children with head lice were randomized to receive each treatment. Two applications of permethrin 1% or dimeticone 4% were done, 1 week apart. However, lindane 1% was used just once for treatment cases. Data analysis was done using SPSS software. Recovery differences between the groups were tested using the chi-squared test. Four hundred forty-four louse-infested schoolgirls were randomly treated with them. Permethrin, lindane, dimeticone, and placebo produced the recovery rates 56.8, 31.5, 51.4, and 10.8% on day 2 post-treatment, respectively. Cure rates were in the permethrin group on days 8 and 15, respectively, 69.4 and 90.1%. The success rates were in the lindane group on days 8 and 15, respectively, 73 and 86.5%. The success rates were in the dimeticone group on days 8 and 15, respectively, 60.4 and 94.6%. It is recommended dimeticone lotion (4%) as a very effective and safe pediculicide for pediculosis control. With proper application, dimethicone can rapidly cure head lice infestation with minimal reinfestation.

Diversity of mitochondrial genes and predominance of Clade B in different head lice populations in the northwest of Iran

BACKGROUND

The head louse, Pediculus humanus capitis, is the most important ectoparasite causing many health problems. Several linkages are presented for this parasite, each representing a particular geographical distribution, prevalence rate, vector competence, susceptibility to pediculicides, and infestation rate. Determining the genetic nature of these linkages is necessary to identify the population structure and also to develop and monitor control programmes against head lice. This study was designed to analyse cox1 and cytb genes and determine the mitochondrial clades in head lice populations in the northwest of Iran.

METHODS

Adult head lice were collected from infested females of Ardabil, East and West Azerbaijan, and Zanjan Provinces from 2016 to 2018. Partial fragments of the mitochondrial genes cox1 and cytb were amplified by PCR and some of the amplicons were sequenced. All confirmed sequences were analysed, and the frequency of each mitochondrial clade was determined in the studied areas.

RESULTS

A total of 6410 females were clinically examined, and 897 adult head lice were collected from 562 infested cases. Genomic DNA was extracted from 417 samples, and fragments of cox1 and cytb genes were amplified in 348 individuals. Analysis of the 116 sequences showed the 632-bp and 495-bp fragments for cox1 and cytb genes, respectively. The nucleotide and haplotype diversities of cytb and cox1 genes were 0.02261 and 0.589 and 0.01443 and 0.424, respectively. Sequence analysis indicated 6 haplotypes clustered in two clades, A and B. The relative prevalence of clade B was 73% for cytb and 82% for cox1 gene. Haplotypes of clade B were found in all the studied areas, while those of clade A were observed only in rural and suburban areas.

CONCLUSIONS

To our knowledge, this is the first study investigated deeply the field populations of Pediculus and documented two clades in the Middle East. The considerable prevalence of pediculosis in the studied areas requires authorities' attention to establish effective control and preventive measures. Given the role of cytb in monitoring population groups, application of this marker is suggested for future epigenetic studies to evaluate the factors affecting the abundance of these clades.

Pediculosis capitis among school-age students worldwide as an emerging public health concern: a systematic review and meta-analysis of past five decades

Pediculosis by Pediculus humanus capitis is still an important health issue in school-age students worldwide. Although pediculicidal agents effectively kill head lice, the re-infestation rate is still high. This study was conducted to provide a summary of evidence about the prevalence of pediculosis capitis among school-age students worldwide. Different databases including MEDLINE/PubMed, Scopus, and Web of Science were searched for publications related to pediculosis capitis in school-age students from 1977 to 2020. All peer-reviewed original research articles describing pediculosis capitis among school-age students were included. Statistical heterogeneity of the different years among studies was assessed using the standard chi squared and I² tests. Due to the significant heterogeneity, a random effect model was adopted to estimate the pooled, continent, and gender-specific prevalence of pediculosis. Two hundred and one papers met the inclusion criteria of this review and entered into the meta-analysis including 1,218,351 individuals. Through a random effect model, the prevalence of pediculosis capitis among school students was estimated as 19% (CI 95% = 0.18-0.20%, I² = 99.89%). The prevalence of pediculosis capitis among boys was 7% (CI 95% = 0.05-0.10) compared to 19% (CI 95% = 0.15-0.24) in girls. The highest prevalence was in Central and South America (33%, CI 95% = 0.22-0.44, I² = 99.81%) and the lowest was in Europe (5%, CI 95% = 4-6, I² = 99.28%). Relatively high pediculosis capitis prevalence among school-age students observed in this study emphasizes the need for implementing screening and prophylaxis tailored to the local context.

Economic Burden Associated with Head Louse (Pediculus humanus capitis) Infestation in Iran

Background

The head louse infestation is a public health issue in the world especially, affecting most people who live in camps, school-aged children and their families. Head lice treatment has economic ramifications that often under calculated. The aim of this study was evaluation of economic burden associated with head louse infestation in Iran.

Methods

In a cross-sectional study, 500,002 infestations were diagnosed among suspected head lice infested people who referred to health care system in all provinces of Iran during 2017. Direct and indirect costs related to paid by patients and government systems were extracted by referring to accounting documents and interviews with patients and experts and were recorded in researcher-made forms. Microsoft Excel 2010 software was used for economic burden calculation.

Results

The incidence rate of head lice infestation in Iran was 500,002/79,926,270 (625.5 per 100,000 populations). Economic burden of head lice in the country was calculated at 5,790,143$. Direct and indirect costs, governmental cost, out of pocket and total costs of head lice were included 3.14$, 2.84$, 5.98$, 5.60$ and 11.58$ per case respectively.

Conclusion

The direct and indirect costs associated with treatment of infestations were relatively high. Therefore, the creation of medical facilities such as availability of diagnostic and treatment strategies can be effective in the control of infestation. The adoption of infestation prevention methods, such as health education to people at risk of infestation, reduces the incidence of head lice and imposition of related treatment costs on governmental health care system and head lice cases.

Assessing the link between head lice infestation and selected cognitive-behavioral factors in a sample of Iranian female adolescents

Background

Head lice infestation is a serious health issue among adolescents in Iran. The primary purpose of the study was to determine the association of head lice infestation with cognitive-behavioral factors in female adolescents.

Methods

The study was cross-sectional, took place between September and October of 2017 in Sarab, East Azerbaijan province, Iran. Using a multi-stage sampling to recruit the study's 226 female adolescents, five of the Sarab's 13 schools were selected through simple random sampling. In the second step, the students were randomly selected using the systematic random sampling method. A survey questionnaire was used to collect the data.

Findings

The prevalence rate of head lice was calculated 20.4%, and the subjects with head lice infestation had lower levels of severity, benefits, self-efficacy, and preventive behaviors. Those without head lice infestation reported adhering to preventive behaviors. The perceived severity and self-efficacy were the statistically significant predictors of head lice infestation and use of preventive behaviors.

Conclusion

Public health authorities, with feedback from the community, must design and implement prevention programs, focusing on mothers and their school-aged children, school principals, and managers of public places as potential change agents. In addition to, perceived severity and self-efficacy should be considered as the key categories when developing these prevention programs.

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.

Prevalence and Alternative Treatment of Head-Lice Infestation in Rural Thailand: A Community-Based Study

Head-lice infestation, pediculosis capitis, remains a public-health burden in many countries. The widely used first-line pediculicides and alternative treatments are often too costly for use in poor socio-economic settings. Ivermectin has been considered an alternate treatment for field practice. This study was composed of 2 parts, a cross-sectional survey and an intervention study. The main objectives were to determine the prevalence and potential factors associated with head-lice infestation, and to evaluate the effectiveness and safety of oral ivermectin administration. A community-based cross-sectional survey was conducted among 890 villagers in rural areas along Thai-Myanmar border. Females with infestations were eligible for the intervention study, and 181 participated in the intervention study. A post-treatment survey was conducted to assess acceptance of ivermectin as a treatment choice. Data analysis used descriptive statistics and a generalized-estimation-equation model adjusted for cluster effect. The study revealed the prevalence of head-lice infestation was 50% among females and only 3% among males. Age stratification showed a high prevalence among females aged <20 years, and among 50% of female school-children. The prevalence was persistent among those with a history of infestation. The major risk factors were residing in a setting with other infected cases, and sharing a hair comb. The study also confirmed that ivermectin was safe and effective for field-based practice. It was considered a preferable treatment option. In conclusion, behavior-change communication should be implemented to reduce the observed high prevalence of headlice infestation. Ivermectin may be an alternative choice for head-lice treatment, especially in remote areas.

Comparative efficacy of three pediculicides to treat head lice infestation in primary school girls: a randomised controlled assessor blind trial in rural Iran

Background

Head lice infestation (Pediculosis) is one of the most important health challenges particularly in primary school-aged children. It is often present among 6–11-year-old students in various tropical and temperate regions of the world. The aim of this study was to examine epidemiologic indices and comparative analysis of two pyrethroid-based and one non-chemical pediculicide products on head lice treatment of primary school girls in a rural setting of Fars province, south Iran, as part of a randomized controlled assessor blind trial.

Methods

Before treatment, infested students were screened using plastic detection combs to find live head lice. Three independent parallel groups, each with about 25 participants (#77) were eventually twice with a week apart treated with either 1% permethrin, 0.2% parasidose (d-phenothrin) or 4% dimeticone lotion preparations. In each case, a questionnaire form was completed on epidemiologic factors. Data were registered after a fortnight from primary scalp treatment and re-inspection on days 2, 6, 9 and 14. Data analyses were performed using Chi-square test with a P-value < 0.05 being taken as statistically significant.

Results

From 3728 inspected students, 87 (2.33%) girls were infested with head lice, Pediculus humanus capitis De Geer, 1778. Ten students dropped out pertaining to exclusion criteria. No significant correlation was found between head lice infestation level and hair length, hair style, itching, nationality, age, settlement site and baths; but there was a significant relationship between age and hair style (P = 0.027). The efficacy values on each of the above re-inspection days from each of the three treatments were 81, 74, 70 and 63% for permethrin; 83, 92, 100 and 100% for dimeticone; and 96, 88, 96 and 92% for d-phenothrin; respectively. A quartile difference in efficacy of permethrin relative to dimeticone on day 14 represented the scale of head lice resistance to permethrin treatment. There were significant statistical differences in case re-inspection days 9 (P = 0.008) and 14 (P = 0.003) post treatment. Only two dropout cases, one non-compliant and the other lost before the second-week treatment, from permethrin trial were observed following two applications a week apart.

Conclusions

Dimeticone lotion had the fullest efficacy (100%) among all treatments. This high cure rate was attributed to the low level of infestation and the extent of patients’ involvement. Parasidose swiftly ameliorated the infested cases by the second day since initial treatment. Female third grade students were the most infested cohort.

Trial registration

Current Controlled Trials- IRCT2016041627408N1, Dated: 21-08-2017.

National and Provincial Prevalence of Pediculus humanus capitis among Urban Students in Iran from 2014 to 2018

BACKGROUND

Pediculosis capitis is one of the most common contagious diseases in overcrowded places, especially in schools. We aimed to determine the overall and seasonal prevalence of Pediculosis capitis (head lice infestation) among Iranian students.

STUDY DESIGN

A repeated cross-sectional study.

METHODS

The present study was conducted among all students, aged 6-18 yr, from urban areas of 31 provinces of Iran from 2014 to 2018. The student's hair and scalp were examined by trained school health instructor. The prevalence (95% Confidence Interval) of pediculosis were estimated overall and stratified by gender. Linear and Poisson regression models were used for data analysis.

RESULTS

Results showed an upward trend of pediculosis from 1.7% to 3.42% during four years of study (P for trend=0.006). Overall, the prevalence of this infestation was significantly higher in girls than boys (P-value<0.05). The relative risk of head lice infestation in autumn was 2.42 times higher than spring (RR: 2.42, 95%CI: 1.35 to 4.32).

CONCLUSION

Pediculosis is still a health issue among Iranian students, especially in girls. This infestation had upward trend in recent years and was more common in southern Iran. Increasing the awareness of students regarding symptoms and complications of pediculosis and using accurate diagnosis methods can be effective in reducing the prevalence of pediculosis and its consequences.

Pediculosis humanus capitis Prevalence as a Health Problem in Girl's Elementary Schools, Southwest of Iran (2017-2018)

BACKGROUND

Head lice as obligated ectoparasite is a public health concern. We aimed to determine the prevalence of Pediculus humanus capitis as public health concern among girl's primary school in southwest of Iran.

STUDY DESIGN

A cross-sectional study.

METHODS

This study was conducted in Karoon County, south-west of Khuzestan Province in Iran in 2017-2018. Totally, 851 students were interviewed randomly, examined by a medical entomologist and completed a questionnaire containing 18 questions based on individual, social, economic, cultural and health information. Results were presented as prevalence and percentages for qualitative variables and also, the data were analyzed by univariate logistic and multivariate regression models.

RESULTS

About 199 (23.38%) girls were infected by head lice. Univariate logistic regression indicated that the prevalence of pediculosis was directly associated with the grade of education, father's job, shared personal hygiene products, number of combing, having permanent head cover at home, infection in other members of the family and previous infection. Multivariate logistic regressions for predicting of head lice infection in girl students were reported permanent head cover at home (OR: 1.399, 95% CI: 0.934, 2.097, P=0.104), grade of education (OR: 1.948, 95% CI: 1.307, 2.905, P=0.001), father's job (OR: 2.385, 95% CI: 1.518, 3.750, P<0.001), shared personal hygiene products (OR: 1.817, 95% CI: 1.224, 2.698, P=0.003) and using hair oil (OR: 1.904, 95% CI: 1.279, 2.836, P=0.002) had significant relation with head lice infestation CONCLUSION: Head lice remind as serious health problem in Karoon County, southwest of Iran. Due to high infestation, periodic screening of the student is recommended for early detection and treatment.

Identification of Novel Voltage-Gated Sodium Channel Mutations in Human Head and Body Lice (Phthiraptera: Pediculidae)

In recent years, the increase of head louse infestation in Iran (7.4%) and especially in West-Azerbaijan Province (248%) has raised the hypothesis of insecticide resistance development. There are different mechanisms of resistance to various groups of insecticides, and knockdown resistance (kdr) is a prominent mechanism of resistance to pyrethroids, an insecticide group which is used conventionally for pediculosis control. For detection of kdr-type well-known amino acid substitutions (M815I-T917I-L920F) and additional sodium channel mutations potentially associated with kdr resistance in head and body lice, louse populations were collected from West-Azerbaijan and Zanjan Provinces of Iran. Six novel mutations were found to be located in the IIS1-2 extracellular loop (H813P) and IIS5 (I927F, L928A, R929V, L930M, and L932M) of the α-subunit. Genotyping results showed that all specimens (100%) have at least one of these or the well-known mutations. Therefore, the presence of kdr-related and novel mutations in the sodium channel is likely to be the reason for the frequent use of pyrethroid insecticides due to treatment failure against lice. Further studies are now required to evaluate the prevalence of the kdr-like mutant allele for monitoring of insecticide resistance and the management of head and body lice in other provinces of the country.

Prevalence of head lice infestation and pediculicidal effect of permethrine shampoo in primary school girls in a low-income area in southeast of Iran

Background

Head lice infestation is a common public health problem that is most prevalent in primary school children throughout the world, especially in developing countries including different parts of Iran. This study aimed to determine the prevalence and risk factors associated with head lice infestation and pediculicidal effect of 1% permethrin shampoo in primary schools girls of Bashagard County, one of the low socioeconomic areas in southeast of Iran.

Methods

In this interventional study six villages with similar demographical situations were selected and randomly assigned into intervention and control areas. In each area 150 girl students aged 7–12 years were selected randomly and screened for head lice infestation by visual scalp examination. In intervention area, treatment efficacy of 1% permethrin shampoo was evaluated via re-examination for infestation after one, two, and three weeks. Pre-tested structured questionnaire was used to collect data on socio-demographic and associated factors of head lice infestation.

Results

The prevalence of head lice infestation was 67.3%. There was significant association between head lice infestation and school grade, family size, parents’ literacy, bathing facilities, frequency of hair washing, and use of shared articles (p < 0.05). The effectiveness of 1% permethrin shampoo for head lice treatment was 29.2, 68.9, and 90.3% after the first, second, and third weeks, respectively.

Conclusion

The head lice infestation is a health problem in primary school girls of Bashagard County. Improvement of socioeconomic status and providing appropriate educational programs about head lice risk factors and prevention can be effective for reduction of infestation in this area.

Trial registration

This trial has been registered and approved by Hormozgan University of Medical Sciences ethical committee (Trial No.764). Trial registration date: March 17 2014.