Use of whole-genome sequence data for fine mapping and genomic prediction of sea louse resistance in Atlantic salmon.

Sea louse (Lepeophtheirus salmonis) infestation of Atlantic salmon (Salmo salar) is a significant challenge in aquaculture. Over the years, this parasite has developed immunity to medicinal control compounds, and non-medicinal control methods have been proven to be stressful, hence the need to study the genomic architecture of salmon resistance to sea lice. Thus, this research used whole-genome sequence (WGS) data to study the genetic basis of the trait since most research using fewer SNPs did not identify significant quantitative trait loci. Mowi Genetics AS provided the genotype (50 k SNPs) and phenotype data for this research after conducting a sea lice challenge test on 3,185 salmon smolts belonging to 191 full-sib families. The 50 k SNP genotype was imputed to WGS using the information from 197 closely related individuals with sequence data. The WGS and 50 k SNPs of the challenged population were then used to estimate genetic parameters, perform a genome-wide association study (GWAS), predict genomic breeding values, and estimate its accuracy for host resistance to sea lice. The heritability of host resistance to sea lice was estimated to be 0.21 and 0.22, while the accuracy of genomic prediction was estimated to be 0.65 and 0.64 for array and WGS data, respectively. In addition, the association test using both array and WGS data did not identify any marker associated with sea lice resistance at the genome-wide level. We conclude that sea lice resistance is a polygenic trait that is moderately heritable. The genomic predictions using medium-density SNP genotyping array were equally good or better than those based on WGS data.

Head lice: impact of COVID-19 and slow recovery of prevalence in Cambridgeshire, UK.

Following school closures and changes in contact behavior of children and adults a reduced head louse prevalence has been reported from across the globe. In parallel, sales of treatments were observed to fall, partly because of supply problems of some products following the pandemic, but this did not appear to result in more cases of infestation. Surveys of schools in and around Cambridge, UK, found that infestation rates were significantly reduced particularly in city schools compared with similar surveys conducted before the COVID-19 pandemic. Contrary to expectation the number of cases in schools has only risen slowly since schools returned to normal full time working in 2022-2023.

The Impact of the COVID-19 Pandemic on the Prevalence of Head Lice Infestation among Children Attending Schools and Kindergartens in Poland.

Pediculosis capitis predominantly affects child populations. During the COVID-19 pandemic, various types of social limitations such as social isolation and limitations on educational facilities' functionalities were introduced worldwide, including in Poland. The impact of these pandemic restrictions on the prevalence of pediculosis capitis has not been extensively investigated so far. Existing data on this topic are limited mainly to indirect evaluation methods, such as online surveys or Internet analysis. In this study, we directly examined a cohort of over five thousand children to assess the influence of COVID-19 pandemic restrictions on the prevalence of head lice infestation among school and kindergarten attendees in Poland. Our findings demonstrate that the restrictions imposed during the COVID-19 pandemic led to a decrease in the number of children infested with head lice compared to pre-pandemic data. These results confirm that head lice infestations remain an ongoing epidemiological concern and warrant continued monitoring.

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

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

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

Prevalence of Pediculus humanus capitis and associated risk factors among elementary school-aged girls in Paveh, West Iran.

INTRODUCTION: Head lice infestation is considered as a common dermatological health problem worldwide. This study was aimed to determine the pediculosis prevalence and associated risk factors among school-aged girls enrolled in public elementary schools of the city of Pave, Kermanshah province, West Iran. The study findings will provide an evidence base, upon which a multifaceted intervention against pediculosis can be formulated and implemented. METHODOLOGY: In this cross-sectional study, 361 elementary school-aged girls were recruited from October to December 2018 at the beginning of the school year. Diagnosis was made by visual inspection. A structured questionnaire was utilized to collect data about past history of infestation and associated factors. RESULTS: A total of 26/361 (7.2%; 95% CI: 4.50-9.90) suffered from pediculosis. Pediculosis was associated with the history of previous infestation (OR: 6.12; 95% CI: 2.68-13.99; p < 0.001), low frequency of bathing (OR: 7.90; 95% CI: 3.36-18.60; p < 0.001), low frequency of hair combing (OR: 3.64; 95% CI: 1.56-8.50; p = 0.004), screening of the student's hair by parents at home (OR: 0.39; 95% CI: 0.19-0.78; p < 0.001) and with the absence of screening by the school health officer in the schools (OR: 7.16; 95% CI: 2.91-17.61; p < 0.001). CONCLUSIONS: Synchronized efforts to enhance public knowledge, periodic examination of school-aged children for pediculosis, and proper treatment of infested patients are needed to control the disease in the Iranian elementary schools. The applied strategies in low and middle income countries is suggested to be focused mainly on low cost family-based and school-based initiatives for maximum effectiveness.

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

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

A simple and selective electrochemical magneto-assay for sea lice eDNA detection developed with a Quality by Design approach.

Environmental DNA (eDNA) is a novel, non-invasive sampling procedure that allows the obtaining of genetic material directly from environmental samples without any evidence of biological sources. The eDNA methodology can greatly benefit from coupling it to reliable, portable and cost-effective tools able to perform decentralized measurements directly at the site of need and in resource-limited settings. Herein, we report a simple method for the selective analysis of eDNA using a magneto-assay with electrochemical detection. The proposed method involves the polymerase chain-reaction (PCR) amplification of mitochondrial eDNA of parasitic Salmon lice (Lepeophtheirus salmonis), extracted from seawater samples. The eDNA sequence was targeted via sandwich hybridization onto magnetic beads and enzymatic labeling was performed to obtain an electroactive product measured by differential pulse voltammetry. Quality by Design (QbD), a recent concept of science- and risk-oriented quality paradigm, was used for the optimization of the different parameters of the assay. Response surface methodology and Monte Carlo simulations were performed to define the method operable design region. The optimized electrochemical magneto-assay attained a limit of detection of 2.9 amol µL-1 of the short synthetic sea louse DNA analogue (43 bp). In addition, robustness testing using a further experimental design approach was performed for monitoring eDNA amplicons. Seawater samples spiked with individuals of free-swimming L. salmonis copepodite stages and seawater collected from tanks with sea lice-infested fish were analyzed.

Forecasting head lice (Pediculidae: Pediculus humanus capitis) infestation incidence hotspots based on spatial correlation analysis in Northwest Iran.

BACKGROUND AND AIM: Pediculus humanus capitis has been prevalent throughout the world, especially in developing countries among elementary students and societies with a weak socio-economic status. This study aimed to forecast head lice (Pediculidae: P. capitis) infestation incidence hotspots based on spatial correlation analysis in Ardabil Province, Northwest Iran. MATERIALS AND METHODS: In this retrospective analytical study, all cases of head lice infestations who were confirmed by Centers for Disease Control office have been studied from 2016 to 2018. Head lice infestation incidence hotspots in the province should be detected based on general G statistics in ArcMap GIS10.4.1. Furthermore, MaxEnt.3.3.3 model was used for modeling the high-risk areas. RESULTS: The prevalence rate of pediculosis was 14.90/100,000 populations. The general G statistics revealed that the head lice infestation in this study area has a high cluster pattern. The analysis showed that the Parsabad and Germi counties were identified as a head lice infestation incidence hotspots. Statistical and spatial analyses of head lice infestation incidence showed a significant positive correlation with head lice infestation incidence hotspots and the altitudes (15-500 m), annual temperature range (14-16.5°C), and slope and average diurnal temperature (12-18°C). CONCLUSION: The results of this study showed that the most ecologically suitable areas of head lice occurrence were identified in two hotspots (Parsabad and Germi) in the Northern areas of Ardabil Province (Parsabad and Germi counties); in the borderline of Iran and the Republic of Azerbaijan.

Risk Factors Associated with Head Lice Infestation in Rural Pediatric Patients.

INTRODUCTION: Head louse infestation is a common parasitic disease in pediatric age group. It is common in collective centers such as schools, garrisons, campuses and old age homes. It is worldwide in distribution with no strict limitation with respect to age, gender and race. AIMS: Present study was conducted to investigate the socio-economic and lifestyle risk factors for head louse infestation in pediatric patients. MATERIALS AND METHODS: An observational descriptive study at a tertiary care hospital in rural Uttar Pradesh over a period of 1 year wherein measurement of disease/risk factors associated with head louse infestation was performed. It was carried out in all children between 5 and 15 years of age using a pre-validated questionnaire. The method of convenience sampling was used and multiple logistic regression was run to account for potential confounding variables using SPSS software. RESULTS: A total of 165 (71.1%) females and 67 (28.8%) males were infested. Most common age group affected was between 5 and 7 years where 97 (41.8%) children were infected. Ninety-five (40.9%) children were in fourth to seventh standards. Parents of 137 (59%) children were not formally educated. Eighty-one (34.9%) children had six members in the family while per capita income was between 5000 and 2500 in families of 139 (59.9%) children. Eighty-seven (37.5%) children had hair length up to shoulders. One twenty-eight (55.1%) children had no family member affected. Seventy-six (32.7%) children took bath twice a week only. CONCLUSION: Social and economic factors as well as lifestyle and education level of patients play a significant role in epidemiology of head lice.

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.

Head Lice among Governmental Primary School Students in Southern Jordan: Prevalence and Risk Factors.

BACKGROUND: Head lice, a common social and health problem among all age groups, is especially widespread among school-aged children. AIMS: This study aimed to assess the prevalence of pediculosis capitis among governmental primary school students in Southern Jordan and its related risk factors. SETTINGS AND DESIGN: A sample of 500 primary schools students aged 6-12 from two male and two female public primary schools in four educational directorates were selected randomly in this cross-sectional study. MATERIALS AND METHODS: Data were collected using a modified questionnaire that was completed by the students with the help of their parents. Students were then asked to return the questionnaire a day ahead of the examination date with a signed consent from the parents. STATISTICAL ANALYSIS: SPSS software was used with Chi-square testing to study the significant relationship between lice infestation prevalence and the independent variables. Statistical significance was set at P < 0.05. RESULTS AND CONCLUSION: The overall prevalence of lice infestation was 20.4% and was significantly higher among girls than boys. The prevalence rate was higher among rural residents, those living in shared rooms, families with a monthly income of <200 Jordanian Dinar, illiterate father and mother, those living in families with more than five members, houses with fewer than three rooms, students with longer hair, those with a history of infestation in the previous year, and students who share home articles with other family members. Female gender, low socioeconomic status, a history of contact, inadequate hygiene practices, and sharing articles were the major risk factors.

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.

Effect of households' social networks on lice infestation among vulnerable Mexican children: a qualitative comparative analysis.

The prevalence of pediculosis is high among elementary and secondary school children, which favors the belief that infestation occurs more often in schools than in homes. This study explored the role of households' social networks in the transmission of head lice. Seventeen school children and their social networks (n = 22) from Acatlipa (Morelos, Mexico) participated in a prospective observational study during school vacation. The hair of all the school children was washed with shampoo containing permethrin at the beginning of the study and the incidence of pediculosis (O) was evaluated at the beginning of the school term (follow-up at 1.5 months). The sets included in the qualitative comparative analysis were sex (S), length of hair (H), baseline diagnostic of pediculosis (I) and degree (D) and infestation index (N) obtained through the analysis of social networks. The prevalence of pediculosis was the same at the beginning and the end of follow-up (17.6%). The degree of the school children's networks ranged between 2 and 14. There were 8 configurations, the most frequent being F*i*d*n*h. The most parsimonious configuration associated with the incidence of pediculosis was F*I*d*H (female, previous infestation, low degree and long hair), with a coverage of 0.344 and a consistency of 0.941. Indicators of social networks made it possible to identify the role of households' social networks in the transmission of lice. Individual actions such as the use of shampoo containing insecticides are temporary and, therefore, structural actions should be favored.