Search Results (27)

Pediculosis remains a public health problem among primary schoolchildren worldwide, including in Thailand. This study aimed to determine the prevalence of pediculosis and identify associated determinants among primary schoolgirls from different socio-geographic regions of Thailand to inform effective control strategies. A cross-sectional survey was conducted among 494 schoolgirls from eastern, northeastern, and southern provinces. Data on demographic characteristics, socioeconomic status, personal hygiene practices, parental knowledge and attitudes toward head lice, and school health policies were collected using questionnaires and interviews with school administrators. Univariable analyses and a generalized linear mixed model (GLMM) with school as a random effect were used to account for clustering. The overall prevalence of pediculosis was 50.81% (95% CI: 46.31–55.20), with significant variation across provinces. In univariable analysis, several factors were associated with infestation. However, after accounting for clustering, only class level (adjusted OR = 3.09; 95% CI: 1.31–7.29) and self-performed hair washing (adjusted OR = 2.93; 95% CI: 1.57–5.49) remained significantly associated with pediculosis, while other associations were attenuated. Parental knowledge was moderate, and commonly held beliefs regarding prevention and treatment varied. None of the participating schools had routine head lice screening policies. These findings indicate that pediculosis is likely influenced by both individual and school-level factors. Control efforts may benefit from coordinated school-based approaches, alongside improved access to effective treatment and targeted health education. Full article

The mitochondrial (mt) genomes of animals, including humans, are typically a single circular chromosome containing all mt genes. In several animal lineages, however, mt genomes have become fragmented, with genes distributed on multiple minichromosomes. How fragmented mt genomes are transcribed is still poorly understood. In this study, we investigated the transcription of the extensively fragmented mt genomes of the human head louse (Pediculus humanus capitis) and the human body louse (Pediculus humanus corporis). RNA-seq reads of both subspecies were retrieved from the NCBI Sequence Read Archive database and mapped to their mt genomes. The transcription level of each mt gene, minichromosome, motif, coding region and non-coding region, measured by RPKM (Reads Per Kilobase of transcript per Million mapped reads), TPM (Transcripts Per Million) or read coverage, was analysed statistically. In both subspecies, mt minichromosomes were transcribed entirely, with coding regions transcribed at much higher levels than non-coding regions. The 37 mt genes are transcribed unevenly, with rrnL, cox1, cox2, cox3 and atp6 transcribed at significantly higher levels than several other genes. Many transcription events terminate near a GC-rich motif in the non-coding regions; however, some transcription events pass this motif, leading to the transcription of entire non-coding regions. Despite the drastic difference in mt genome organisation, the human lice share several transcriptional features with humans, but also have unique features related to their fragmented mt genome organisation. The current study represents the first effort into the transcription of fragmented mt genomes. As more RNA-seq data become available, further studies on other animals with fragmented mt genomes are necessary to fully understand how genome fragmentation affects transcription. Full article

Pediculosis produced by the presence of the human head louse (Pediculus humanus capitis DeGeer, 1767) and the body louse (Pediculus humanus humanus L., 1758) remains a neglected tropical disease in Nigeria, where permethrin-based pediculicides are widely used. However, the resistance status of lice populations has not been previously assessed. Knockdown resistance (kdr) to pyrethroids is primarily driven by two mutations—T917I and L920F—in the voltage-sensitive sodium channel (VSSC) gene. This study investigated the presence of these mutations in 85 head and body lice collected from school-age children in two settlements in Nigeria. The T917I mutation was detected in head lice at frequencies ranging from 21% to 76%, and in body lice from 10% to 95%, with significant variation between sites and louse types. Remarkably, all lice examined carried the L920F mutation, regardless of T917I genotype, a pattern not previously reported in body lice. These findings suggest that pyrethroid resistance is well established or under active selection in the study populations. This is the first report of kdr mutations in human lice from Nigeria and highlights the urgent need for resistance monitoring programs. Early genetic surveillance of these mutations can inform treatment strategies and help prevent widespread resistance in lice populations, preserving the efficacy of available pediculicides. Full article

The treatment of parasitic infections has evolved in terms of effectiveness and the prevention of drug resistance. This is highlighted by the discovery of ivermectin (IVM), a macrocyclic lactone and broad-spectrum antiparasitic agent. IVM garnered scientific attention by presenting a therapeutic alternative in the field of veterinary medicine due to its control of multiple parasite species, including nematodes and soil-transmitted helminths. Shortly after its discovery, IVM was approved for human use by the World Health Organization (WHO) and United States Food and Drug Administration (FDA) for combating head lice, onchocerciasis, rosacea, scabies, and worm infestations within the gastrointestinal tract (GIT). In veterinary medicine, IVM is available in a range of formulations and can be administered via different routes (i.e., oral, topical, and parenteral), whereas for humans, IVM is only approved as a single oral dose and dermal cream. Establishing a comprehensive overview of IVM’s applications in both human and veterinary medicine is necessary, particularly in light of its repurposing potential as a treatment for various conditions and emerging diseases. Given its primary application in veterinary medicine, there is a need to enhance the development of dosage forms suitable for human use. Therefore, this review details the discovery, mechanisms, and applications of IVM, while also examining the challenges of resistance, side-effects, and controversy surrounding its use, to ultimately emphasize the importance of targeted, optimized IVM delivery via tailored dosage form development in animals and humans as part of the One Health approach to interlink innovations across veterinary and human medicine fields. Full article

Indigenous people possess unique health literacy issues and challenges with preventing infectious diseases. This research assessed the baseline knowledge and misinformation in the Semai indigenous subgroup in Perak state, Malaysia, and the impact of a culturally adapted health education intervention. A single-group pre-test/post-test design was used with 156 participants ranging from 7 to 69 years old, predominantly children. The survey addressed key issues of head lice, intestinal parasites, tuberculosis (TB), handwashing, and germ transmission. An interactive, multi-station health education session in the local language produced a significant increase in overall knowledge (mean score increased from 3.17 to 3.83 out of 5, p < 0.0001), with the largest increase among the adult group aged 31–50 years. This was most notable for handwashing knowledge, which had the greatest increase, and misconceptions about intestinal worms and head lice remained. Differences in outcome by age suggest the need for targeted educational strategies, particularly for teenagers and elderly individuals who achieved less gain. The results support the effectiveness of culturally tailored, community-based health education in promoting the awareness of disease among indigenous communities. The drawbacks are convenience sampling, the child dominance of the sample, and the short-term follow-up. Future emphasis should be placed on long-term, community-based intervention using culturally tailored content and digital media. Full article

Sea lice have been a persistent pest of the salmon farming industry for more than 50 years. In this study, we aimed to identify if different strains of Atlantic salmon with discrete long-term lice exposure histories had variable resistance to copepodid attachment and/or different attachment-specific transcriptome patterns. We additionally sought to characterize lice distributions on fins, head, and skin and identify if attachment location influenced transcriptomic profiles of lice. Lice counts were correlated with body size and highest on St. John River (SJR; open ocean-run) relative to Grand Lakes Stream (GLS; 200-year restricted ocean-run) or Sebago Lake (CAS; ~11,000 years landlocked) Atlantic salmon. However, lice density was similar between strains. Skin and fins had expectedly different transcriptomic profiles; however, notable differences were not observed between salmon strains. Variance in lice transcriptomes was minimally affected by attachment location even though lice strongly preferred fins relative to head or body. Attached lice did have different transcriptomic profiles on GLS relative to CAS or SJR. This study cumulatively identified a minimal host evolutionary component for sea lice attachment resistance, although lice behavior post-attachment appeared somewhat affected by strain. Non-uniform settlement distributions and tank-specific variability in lice attachment were observed across populations. Full article

Background/Objectives: Head lice is an ever-present public health issue, especially among the child population. The diagnosis of head lice infestation should be based on direct examination of the scalp, but, in practice, this standard is often not followed, giving way to indirect methods, such as questionnaires or sales reports of delousing shampoos. In Poland, there is no national pediculosis capitis control strategy; therefore, the aim of this study was to determine the prevalence and associated factors of head lice infestation in schools and kindergartens in the years 2021–2023. Methods: Children aged from 3 to 14 years old were directly examined by certified nurses. The same educational institutions were examined across 2021–2023. No personal data of the children were gathered. Results: The prevalence of head lice infestation among children ranged from 8% to 13%, with significantly higher intensity and prevalence observed in girls compared to boys. Conclusions: The prevalence of pediculosis capitis among children in Poland remains persistent and relatively stable over the monitored period. Gender emerged as a significant factor, showing a strong association with both the intensity and extent of head lice infestation. Full article

Pediculus humanus capitis infestation is one of the most underestimated parasitoses still constituting a current epidemiological and social problem. Haematophagous insects, the etiological factor of pediculosis capitis, spread most easily in preschool children, which is determined by social and behavioural aspects. The study aimed to search for factors contributing to pediculosis capitis persistence in kindergartens located in south-eastern Poland. For this purpose, anonymous surveys among the management staff of preschool institutions were conducted. Head lice infestations were reported in 87.0% of the 561 surveyed facilities. A positive correlation was confirmed between the prevalence of head lice and a higher number of children in these facilities. Additionally, in 69.3% of the facilities where cases of pediculosis capitis were reported, it was noted that the infestation was associated with the child’s attendance at preschool. Familial and occupational transmission was observed in 78.5% and 25.2% of the facilities, respectively. In contrast, in 93.2% of preschools where no cases of infestation were reported, all parents consented to periodic head inspections. Parents’ attitudes and their perception of head lice as a health issue, rather than an embarrassing problem, appear to be key factors in effectively limiting the spread of head lice in the studied kindergartens. Full article

The infestation of ectoparasites poses a severe problem in animal breeding, severely affecting animal health and causing substantial economic losses. However, limited information is available regarding lice infestations in plateau livestock. To address this, we collected and examined lice samples from Tibetan yaks, pigs and sheep, amplifying the rrnS and cox1 genes for evolutionary analysis. The results revealed that the prevalence of lice was 51.3% (95% CI: 44.0–58.6%) in yaks, Tibetan sheep and Tibetan pigs, with regional prevalence ranging from 7.7% to 67.5%. Morphometric analysis showed that female lice were bigger than male lice. In Tibetan pigs, females exhibited a prominent longer body length (p < 0.05), belly length (p < 0.01) and body length to body width ratio (p < 0.05). In yaks, females had longer body length (p < 0.01) and body width (p < 0.05). For Tibetan sheep, female lice had larger body length (p < 0.001), body width (p < 0.001), head length (p < 0.05) and belly length (p < 0.05). Additionally, molecular identification revealed that lice infesting wild and domestic yaks were Linognathus vituli with 96.59–98.78% (wild yaks) and 96.33–98.71% (yaks) similarity to the OL677823.1 isolate. Lice infesting Tibetan sheep were identified as Linognathus africanus, showing 99.02–99.76% similarity to the OP948898.1 isolate. Lice from Tibetan pigs were identified as Haematopinus apri, with 96.38–98.31% similarity to the ON000922.1 isolate. Moreover, cox1 gene analysis of lice from Tibetan pigs showed 96.97–97.72% similarity to the KC814616.1 isolate. It is concluded that these findings could provide valuable insights into the prevention and control of lice-related diseases in plateau animals, enhancing animal health and mitigating economic losses. Full article

Head lice infestation (HLI), caused by Pediculus humanus capitis De Geer, 1767, has long been a common global problem of school children. Permethrin is an old pyrethroid derivative that has been used commonly for its treatment, and it exerts its activity over the voltage-sensitive calcium channels (VSCC) of the lice. There has been a growing list of persistent HLI cases lately in the world among patients using permethrin, and knockdown resistance (kdr)-related point mutations on VSCC have been identified and reported from those resistant lice samples. The aim of this study was to investigate the gene mutations associated with permethrin resistance in head lice collected from primary school children in Istanbul (Türkiye) and Nagarkot (Nepal) for the first time. A total of 192 P. h. capitis adults were collected from school children aged 6–12 years in two cities (96 lice each). Following DNA isolation, the fragment of the VSCC a-subunit gene, which contained the possible mutation sites ((kdr-like M815I (ATG > ATT), kdr T917I (ACA > ATA), and kdr-like L920F (CTT > TTT)), was amplified in each louse by PCR, and the PCR products were sequenced and aligned, followed by frequency calculations for alleles, genotypes, and haplotypes. Using nucleic acid sequence analysis, it was revealed that M815I, T917I, or L920F mutations were present on the VSCC genes in the lice samples from both Türkiye and Nepal. In addition, genotypic analyses indicated the presence of all three mutations in the lice samples from Türkiye, while the T917I mutation was detected in none of the lice collected in Nepal. This is the first report of gene mutations associated with permethrin resistance in head lice collected from a group of primary school children in the largest city of Türkiye (Istanbul) and Nagarkot. High mutation rates were identified in the lice, especially those from Istanbul, which is concordant with our previous unpublished study, in which almost 60% of the examined lice of the school children (in the same school selected in this study) remained alive despite long-term exposure to permethrin in the laboratory. These initial results show that gene mutations associated with permethrin resistance are common in lice samples in Istanbul and Nagarkot, which may suggest the current need for the selection of new pediculicidal agents in HLI treatment. Full article

The genus Strophantus belongs to the Apocynaceae family of flowering plants which grows primarily in tropical Africa. The plants are widely used in traditional herbal medicine. S. sarmentosus, in particular, is used for the treatment of, e.g., joint pain and rheumatoid arthritis, wound infections, head lice, diarrhea, snake bite, and eye conditions. Despite its widespread use, dedicated research characterizing its bioactive plant components is scarce. Investigations have focused mainly on its cardenolides because of their cardioactivity and historical use as cardiotonic. There are also studies concerning the antibacterial, antioxidant, and anti-inflammatory activity of plant extracts. This review summarizes the present knowledge surrounding the biochemical and analytical research on Strophantus, in general, and S. sarmentosus, in particular, and describes the current state of the field based on the available scientific literature. Full article

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. Full article

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

Salmon aquaculture is constantly threatened by pathogens that impact fish health, welfare, and productivity, including the sea louse Caligus rogercresseyi. This marine ectoparasite is mainly controlled through delousing drug treatments that have lost efficacy. Therein, strategies such as salmon breeding selection represent a sustainable alternative to produce fish with resistance to sea lice. This study explored the whole-transcriptome changes in Atlantic salmon families with contrasting resistance phenotypes against lice infestation. In total, 121 Atlantic salmon families were challenged with 35 copepodites per fish and ranked after 14 infestation days. Skin and head kidney tissue from the top two lowest (R) and highest (S) infested families were sequenced by the Illumina platform. Genome-scale transcriptome analysis showed different expression profiles between the phenotypes. Significant differences in chromosome modulation between the R and S families were observed in skin tissue. Notably, the upregulation of genes associated with tissue repairs, such as collagen and myosin, was found in R families. Furthermore, skin tissue of resistant families showed the highest number of genes associated with molecular functions such as ion binding, transferase, and cytokine activity, compared with the susceptible. Interestingly, lncRNAs differentially modulated in the R/S families are located near genes associated with immune response, which are upregulated in the R family. Finally, SNPs variations were identified in both salmon families, where the resistant ones showed the highest number of SNPs variations. Remarkably, among the genes with SPNs, genes associated with the tissue repair process were identified. This study reported Atlantic salmon chromosome regions exclusively expressed in R or S Atlantic salmon families’ phenotypes. Furthermore, due to the presence of SNPs and high expression of tissue repair genes in the resistant families, it is possible to suggest mucosal immune activation associated with the Atlantic salmon resistance to sea louse infestation. Full article

The development of vaccines against sea lice in salmon farming is complex, expensive, and takes several years for commercial availability. Recently, transcriptome studies in sea louse have provided valuable information for identifying relevant molecules with potential use for fish vaccines. However, the bottleneck is the in vivo testing of recombinant protein candidates, the dosage, and the polyvalent formulation strategies. This study explored a cell-based approach to prospect antigens as candidate vaccines against sea lice by comparison with immunized fish. Herein, SHK-1 cells and Atlantic salmon head kidney tissue were exposed to the antigen cathepsin identified from the sea louse Caligus rogercresseyi. The cathepsin protein was cloned and recombinantly expressed in Escherichia coli, and then SHK-1 cell lines were stimulated with 100 ng/mL cathepsin recombinant for 24 h. In addition, Atlantic salmons were vaccinated with 30 ug/mL recombinant protein, and head kidney samples were then collected 30 days post-immunization. SHK-1 cells and salmon head kidney exposed to cathepsin were analyzed by Illumina RNA sequencing. The statistical comparisons showed differences in the transcriptomic profiles between SHK-1 cells and the salmon head kidney. However, 24.15% of the differentially expressed genes were shared. Moreover, putative gene regulation through lncRNAs revealed tissue-specific transcription patterns. The top 50 up and downregulated lncRNAs were highly correlated with genes involved in immune response, iron homeostasis, pro-inflammatory cytokines, and apoptosis. Also, highly enriched pathways related to the immune system and signal transduction were shared between both tissues. These findings highlight a novel approach to evaluating candidate antigens for sea lice vaccine development, improving the antigens screening in the SHK-1 cell line model. Full article