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Yersinia pestis can infect the Pawlowsky glands of human body lice and be transmitted by louse bite.PLoS Biology May 2024Yersinia pestis, the causative agent of plague, is a highly lethal vector-borne pathogen responsible for killing large portions of Europe's population during the Black...
Yersinia pestis, the causative agent of plague, is a highly lethal vector-borne pathogen responsible for killing large portions of Europe's population during the Black Death of the Middle Ages. In the wild, Y. pestis cycles between fleas and rodents; occasionally spilling over into humans bitten by infectious fleas. For this reason, fleas and the rats harboring them have been considered the main epidemiological drivers of previous plague pandemics. Human ectoparasites, such as the body louse (Pediculus humanus humanus), have largely been discounted due to their reputation as inefficient vectors of plague bacilli. Using a membrane-feeder adapted strain of body lice, we show that the digestive tract of some body lice become chronically infected with Y. pestis at bacteremia as low as 1 × 105 CFU/ml, and these lice routinely defecate Y. pestis. At higher bacteremia (≥1 × 107 CFU/ml), a subset of the lice develop an infection within the Pawlowsky glands (PGs), a pair of putative accessory salivary glands in the louse head. Lice that developed PG infection transmitted Y. pestis more consistently than those with bacteria only in the digestive tract. These glands are thought to secrete lubricant onto the mouthparts, and we hypothesize that when infected, their secretions contaminate the mouthparts prior to feeding, resulting in bite-based transmission of Y. pestis. The body louse's high level of susceptibility to infection by gram-negative bacteria and their potential to transmit plague bacilli by multiple mechanisms supports the hypothesis that they may have played a role in previous human plague pandemics and local outbreaks.
Topics: Animals; Yersinia pestis; Pediculus; Humans; Plague; Insect Vectors; Insect Bites and Stings; Female; Male
PubMed: 38771885
DOI: 10.1371/journal.pbio.3002625 -
The Pan African Medical Journal 2024
Topics: Animals; Humans; Pediculus; Eyelashes; Lice Infestations
PubMed: 38558554
DOI: 10.11604/pamj.2024.47.29.42559 -
Molecular Biology and Evolution Apr 2024Insects have repeatedly forged symbioses with heritable microbes, gaining novel traits. For the microbe, the transition to symbioses can lead to the degeneration of the...
Insects have repeatedly forged symbioses with heritable microbes, gaining novel traits. For the microbe, the transition to symbioses can lead to the degeneration of the symbiont's genome through transmission bottlenecks, isolation, and the loss of DNA repair enzymes. However, some insect-microbial symbioses have persisted for millions of years, suggesting that natural selection slows genetic drift and maintains functional consistency between symbiont populations. By sampling in multiple countries, we examine genomic diversity within a symbiont species, a heritable symbiotic bacterium found only in human head lice. We find that human head louse symbionts contain genetic diversity that appears to have arisen contemporaneously with the appearance of anatomically modern humans within Africa and/or during the colonization of Eurasia by humans. We predict that the observed genetic diversity underlies functional differences in extant symbiont lineages, through the inactivation of genes involved in symbiont membrane construction. Furthermore, we find evidence of additional gene losses prior to the appearance of modern humans, also impacting the symbiont membrane. From this, we conclude that symbiont genome degeneration is proceeding, via gene inactivation and subsequent loss, in human head louse symbionts, while genomic diversity is maintained. Collectively, our results provide a look into the genomic diversity within a single symbiont species and highlight the shared evolutionary history of humans, lice, and bacteria.
Topics: Animals; Humans; Pediculus; Phylogeny; Genome, Bacterial; Evolution, Molecular; Bacteria; Genomics; Hominidae; Insecta; Symbiosis
PubMed: 38513084
DOI: 10.1093/molbev/msae064 -
Actas Dermo-sifiliograficas May 2024Sexually transmitted infections are communicable diseases where the pathogen is transmitted through sexual contact. The Sexually Transmitted Infections Working Group of...
[Translated article] Spanish Academy of Dermatology and Venereology (AEDV) expert recommendations for the management of sexual transmitted parasitosis. Scabies, and pediculosis pubis.
Sexually transmitted infections are communicable diseases where the pathogen is transmitted through sexual contact. The Sexually Transmitted Infections Working Group of the Spanish Academy of Dermatology and Venereology (AEDV) is engaged in the drafting of documents to guide dermatologists and health care personnel who treat Spanish patients with these infections. This document analyzes the epidemiological, clinical, therapeutic, and control characteristics of 2 sexually transmitted parasitosis: scabies due to Sarcoptes scabiei var. hominis, and pubic pediculosis due to Phthirus pubis. Both parasitoses share a sort of mixed spread through sexual and community transmission regardless of the route through which the infection was initially acquired. This specific feature creates particularities in the management and control of the infestation.
Topics: Humans; Scabies; Lice Infestations; Female; Male; Sexually Transmitted Diseases; Spain; Animals; Phthirus
PubMed: 38479688
DOI: 10.1016/j.ad.2024.03.016 -
Genome Biology and Evolution Mar 2024Sucking lice of the parvorder Anoplura are permanent ectoparasites with specific lifestyle and highly derived features. Currently, genomic data are only available for a...
Sucking lice of the parvorder Anoplura are permanent ectoparasites with specific lifestyle and highly derived features. Currently, genomic data are only available for a single species, the human louse Pediculus humanus. Here, we present genomes of two distinct lineages, with different host spectra, of a rodent louse Polyplax serrata. Genomes of these ecologically different lineages are closely similar in gene content and display a conserved order of genes, with the exception of a single translocation. Compared with P. humanus, the P. serrata genomes are noticeably larger (139 vs. 111 Mbp) and encode a higher number of genes. Similar to P. humanus, they are reduced in sensory-related categories such as vision and olfaction. Utilizing genome-wide data, we perform phylogenetic reconstruction and evolutionary dating of the P. serrata lineages. Obtained estimates reveal their relatively deep divergence (∼6.5 Mya), comparable with the split between the human and chimpanzee lice P. humanus and Pediculus schaeffi. This supports the view that the P. serrata lineages are likely to represent two cryptic species with different host spectra. Historical demographies show glaciation-related population size (Ne) reduction, but recent restoration of Ne was seen only in the less host-specific lineage. Together with the louse genomes, we analyze genomes of their bacterial symbiont Legionella polyplacis and evaluate their potential complementarity in synthesis of amino acids and B vitamins. We show that both systems, Polyplax/Legionella and Pediculus/Riesia, display almost identical patterns, with symbionts involved in synthesis of B vitamins but not amino acids.
Topics: Animals; Humans; Phylogeny; Rodentia; Vitamin B Complex; Anoplura; Pediculus; Legionella; Host Specificity
PubMed: 38478715
DOI: 10.1093/gbe/evae045 -
Turkiye Parazitolojii Dergisi Mar 2024The purpose of this study was to investigate the prevalence of intestinal parasites and head lice in primary school-aged children and to determine a possible...
OBJECTIVE
The purpose of this study was to investigate the prevalence of intestinal parasites and head lice in primary school-aged children and to determine a possible relationship between the co-occurrence of ecto-endoparasites.
METHODS
The study were conducted in three schools in the center of Sivas: Sivas Karşıyaka Primary School, Kılavuz İMKB Primary School, and Karşıyaka 27 June Middle School. The presence of head lice and intestinal parasites was investigated in a total of 563 children aged 6 to 17, with 294 girls and 269 boys. Classroom teachers and students were provided with information about intestinal parasites, head lice, and methods of transmission and prevention, and a questionnaire was administered. During the head lice examination, students were inspected with a comb, and samples with nits were examined under a microscope in the laboratory. Cellophane tape and stool samples obtained from the participants were examined on the same day using the native-lugol, flotation, and trichrome staining methods under a light microscope (x10, x40, x100).
RESULTS
Five hundred sixty-three children were evaluated for head lice and 15 (2.6%) were found to be positive. During the examination, only nits were found in 11 students (1.9%), and both adult lice and nymphs were seen in 4 students (0.7%). Head lice were found positive in 2 out of 269 boys (0.7%), while 13 out of 294 girls (4.2%) positive (p<0.05). As a result of stool examination in children, was found in 11 (1.95%), in 4 (0.71%), sp. in 14 (2.48%), in 8 (1.42%) and spp. in 2 (0.35%). Head lice infestation and spp. were found to coexist in 2 (0.35%) children.
CONCLUSION
In conclusion, although there has been a noticeable decrease in head lice and intestinal parasites among primary school-aged children in Sivas province, these conditions are still present, as evidenced by previous studies conducted in our region.
Topics: Adult; Male; Child; Female; Animals; Humans; Pediculus; Lice Infestations; Parasites; Intestinal Diseases, Parasitic; Schools
PubMed: 38449365
DOI: 10.4274/tpd.galenos.2023.04796 -
BMC Research Notes Feb 2024The report of the outbreak of body louse in northwestern Iran after three decades reminds us again of the danger of the re-emerging of previous epidemics.
OBJECTIVE
The report of the outbreak of body louse in northwestern Iran after three decades reminds us again of the danger of the re-emerging of previous epidemics.
RESULTS
The results of the study that nearly 70% of the patients in a rehabilitation Centre were infected with body louse. In this study, scientific measures were taken to prevent the spread of body lice to healthy people, including isolation of the patients, washing the clothes of those infected at high temperatures, and spraying the rest area, beddings, and blankets. This is a more recent report on an outbreak of body louse in Iran in 2023.
Topics: Animals; Humans; Pediculus; Iran; Lice Infestations; Disease Outbreaks
PubMed: 38378626
DOI: 10.1186/s13104-024-06709-8 -
BMC Infectious Diseases Jan 2024Head 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...
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.
Topics: Animals; Adult; Humans; Lice Infestations; Permethrin; Propensity Score; Dimethylpolysiloxanes; Pediculus; Insecticides
PubMed: 38291370
DOI: 10.1186/s12879-024-09029-1 -
The Veterinary Quarterly Dec 2024Southern pudu () is a threatened endemic deer of the temperate forests of Chile. In recent years pudu populations rates have decreased mainly due to anthropogenic causes...
Parasitic findings on threatened pudu deer from Central Chile accounts first genetic characterization of lice parasitizing in Chile and the first molecular report of metacestodes in this species.
Southern pudu () is a threatened endemic deer of the temperate forests of Chile. In recent years pudu populations rates have decreased mainly due to anthropogenic causes including forest loss and landscape fragmentation. In this context, the parasitic fauna of Chilean pudu has been scarcely investigated. The aim of this study was to determine the parasitic status of rescued pudu = 13 from its natural habitat in Central Chile (Maule region) during March 2022 and June 2023 by applying morphological, histopathological, and molecular analyses. As result, we report the presence of transmission of parasites from dogs to pudus as showed by the presence of metacestodes of the parasite on omentum, liver, and pleura of pudus during postmortem examinations, being the first molecular report on the presence of this parasite on Chilean pudu. Meanwhile, ectoparasite examinations determined the presence of chewing and sucking lice on pudu exemplars here analysed. Molecular and phylogenetic analysis of lice revealed new insights on and lice parasitizing in Chile, equally being the first genetic characterization of lice parasitizing pudu exemplars in Chile. In addition, parasite loads of lice and metacestodes were analysed. However, no statistically significance was observed when comparing environmental and individual traits influence on parasite load variation. Overall, the study area is the northern limit of habitat distribution of this specie in Chile and we here provide novel information on pudu deer parasites, thus making a useful and valuable contribution to the parasitological knowledge on this threatened species.
Topics: Animals; Dogs; Deer; Parasites; Taenia; Chile; Phylogeny; Anoplura
PubMed: 38241082
DOI: 10.1080/01652176.2024.2302027 -
Scientific Reports Jan 2024This interdisciplinary study examined the relationship between bone density and drilling forces required during trans-pedicular access to the vertebra using fresh-frozen...
Correlation of CT-based bone mineralization with drilling-force measurements in anatomical specimens is suitable to investigate planning of trans-pedicular spine interventions.
This interdisciplinary study examined the relationship between bone density and drilling forces required during trans-pedicular access to the vertebra using fresh-frozen thoraco-lumbar vertebrae from two female body donors (A, B). Before and after biomechanical examination, samples underwent high-resolution CT-quantification of total bone density followed by software-based evaluation and processing. CT density measurements (n = 4818) were calculated as gray values (GV), which were highest in T12 for both subjects (GV = 3483.24, GV = 3160.33). Trans-pedicular drilling forces F (Newton N) were highest in L3 (F = 5.67 N) and L4 (F = 5.65 N). In 12 out of 13 specimens, GVs significantly (p < 0.001) correlated with force measurements. Among these, Spearman correlations r were poor in two lumbar vertebrae, fair in five specimens, and moderately strong in another five specimens, and highest for T11 (r = 0.721) and L5 (r = 0.690). Our results indicate that CT-based analysis of vertebral bone density acquired in anatomical specimens is a promising approach to predict the drilling force appearance as surrogate parameter of its biomechanical properties by e.g., linear regression analysis. The study may be of value as basis for biomechanical investigations to improve planning of the optimal trajectory and to define safety margins for drilling forces during robotic-assisted trans-pedicular interventions on the spine in the future.
Topics: Humans; Female; Animals; Tomography, X-Ray Computed; Calcification, Physiologic; Bone Density; Lumbar Vertebrae; Anoplura
PubMed: 38238459
DOI: 10.1038/s41598-023-50204-2