Sarcoptes scabiei mites in humans are distributed into three genetically distinct clades

AbstractScabies is an ectoparasitic infestation caused by the mite Sarcoptes scabiei. Currently, S. scabiei is taxonomically divided into different varieties on the basis of host origin. Genetics-based research on scabies has been conducted, but the data on genetic diversity of populations of this mite in humans in Europe are lacking. We evaluated the genetic diversity of populations of S. scabiei. A large series of mites obtained from humans in France and the data of mites from various hosts and geographical areas retrieved from GenBank were included to investigate whether mites are divided into distinct populations. The study of cytochrome c oxidase subunit 1 gene polymorphisms were found to be best suited for phylogenetic analysis. S. scabiei mites were distributed into three genetically distinct clades, with most mites clustering in clades B and C. The Fst value and the Nm value calculated for mites included in clades B and C indicated a strong population structure and a very low gene flow between mites of those clades. The results of the present study not only support the rejection of the hypothesis of panmixia for S. scabiei in humans but also suggest that mites belonging to different clades are genetically isolated. Moreover, the results suggest that the subdivision of S. scabies in varieties according to animal or human hosts is not warranted. In conclusion, S. scabiei mites in humans do not constitute a homogeneous population. Further investigations are now required to assess whether different clinical forms of scabies are associated with particular haplotypes or clades

The 2020 International Alliance for the Control of Scabies Consensus Criteria for the Diagnosis of Scabies.

BACKGROUND: Scabies is a common parasitic skin condition that causes considerable morbidity globally. Clinical and epidemiological research for scabies has been limited by a lack of standardization of diagnostic methods. OBJECTIVES: To develop consensus criteria for the diagnosis of common scabies that could be implemented in a variety of settings. METHODS: Consensus diagnostic criteria were developed through a Delphi study with international experts. Detailed recommendations were collected from the expert panel to define the criteria features and guide their implementation. These comments were then combined with a comprehensive review of the available literature and the opinion of an expanded group of international experts to develop detailed, evidence-based definitions and diagnostic methods. RESULTS: The 2020 International Alliance for the Control of Scabies (IACS) Consensus Criteria for the Diagnosis of Scabies include three levels of diagnostic certainty and eight subcategories. Confirmed scabies (level A) requires direct visualization of the mite or its products. Clinical scabies (level B) and suspected scabies (level C) rely on clinical assessment of signs and symptoms. Evidence-based, consensus methods for microscopy, visualization and clinical symptoms and signs were developed, along with a media library. CONCLUSIONS: The 2020 IACS Criteria represent a pragmatic yet robust set of diagnostic features and methods. The criteria may be implemented in a range of research, public health and clinical settings by selecting the appropriate diagnostic levels and subcategories. These criteria may provide greater consistency and standardization for scabies diagnosis. Validation studies, development of training materials and development of survey methods are now required. What is already known about this topic? The diagnosis of scabies is limited by the lack of accurate, objective tests. Microscopy of skin scrapings can confirm the diagnosis, but it is insensitive, invasive and often impractical. Diagnosis usually relies on clinical assessment, although visualization using dermoscopy is becoming increasingly common. These diagnostic methods have not been standardized, hampering the interpretation of findings from clinical research and epidemiological surveys, and the development of scabies control strategies. What does this study add? International consensus diagnostic criteria for common scabies were developed through a Delphi study with global experts. The 2020 International Alliance for the Control of Scabies (IACS) Criteria categorize diagnosis at three levels of diagnostic certainty (confirmed, clinical and suspected scabies) and eight subcategories, and can be adapted to a range of research and public health settings. Detailed definitions and figures are included to aid training and implementation. The 2020 IACS Criteria may facilitate the standardization of scabies diagnosis

Les Houches 2019 Physics at TeV Colliders: New Physics Working Group Report

This report presents the activities of the `New Physics' working group for the `Physics at TeV Colliders' workshop (Les Houches, France, 10--28 June, 2019). These activities include studies of direct searches for new physics, approaches to exploit published data to constrain new physics, as well as the development of tools to further facilitate these investigations. Benefits of machine learning for both the search for new physics and the interpretation of these searches are also presented

Supplementary Data: How to eliminate scabies parasites from fomites – a high throughput ex vivo experimental study.

Research Hypothesis: To date, no field studies have been performed to validate decontamination measures for scabies infested textiles. As there is no in vitro culture, previous experimental research was limited in parasite numbers and did not consider the egg stage. Accordingly, the existing decontamination protocols are based on poor statistical power and vary significantly, resulting in confusion of patients and medical workers. We aimed to generate statistically valid experimental data as a basis to develop standardized guidelines with clear and simple directions for scabies outbreaks. Over 5,500 adult mites and 2,300 eggs of S. scabiei were obtained from a porcine model, exposed to 89 different conditions, and individually monitored in custom designed wire mesh pouches (video) in experimental groups of 20-25. Initial in vitro mite survival and egg hatching assays (Supplemental Table 1) informed subsequent real life ex vivo experiments (Supplemental Table 2), resulting in a simple strategic flowchart for decontamination

Supplementary Data: How to eliminate scabies parasites from fomites – a high throughput ex vivo experimental study.

Research Hypothesis: To date, no field studies have been performed to validate decontamination measures for scabies infested textiles. As there is no in vitro culture, previous experimental research was limited in parasite numbers and did not consider the egg stage. Accordingly, the existing decontamination protocols are based on poor statistical power and vary significantly, resulting in confusion of patients and medical workers. We aimed to generate statistically valid experimental data as a basis to develop standardized guidelines with clear and simple directions for scabies outbreaks. Over 5,500 adult mites and 2,300 eggs of S. scabiei were obtained from a porcine model, exposed to 89 different conditions, and individually monitored in custom designed wire mesh pouches (video) in experimental groups of 20-25. Initial in vitro mite survival and egg hatching assays (Supplemental Table 1) informed subsequent real life ex vivo experiments (Supplemental Table 2), resulting in a simple strategic flowchart for decontamination