28 research outputs found

    Erratum for Williams et al., "Investigation of the Plasma Virome from Cases of Unexplained Febrile Illness in Tanzania from 2013 to 2014: a Comparative Analysis between Unbiased and VirCapSeq-VERT High-Throughput Sequencing Approaches"

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    High-throughput sequencing can provide insights into epidemiology and medicine through comprehensive surveys of viral genetic sequences in environmental and clinical samples. Here, we characterize the plasma virome of Tanzanian patients with unexplained febrile illness by using two high-throughput sequencing methods: unbiased sequencing and VirCapSeq-VERT (a positive selection system). Sequences from dengue virus 2, West Nile virus, human immunodeficiency virus type 1, human pegivirus, and Epstein-Barr virus were identified in plasma. Both sequencing strategies recovered nearly complete genomes in samples containing multiple viruses. Whereas VirCapSeq-VERT had better sensitivity, unbiased sequencing provided better coverage of genome termini. Together, these data demonstrate the utility of high-throughput sequencing strategies in outbreak investigations. <b>IMPORTANCE</b> Characterization of the viruses found in the blood of febrile patients provides information pertinent to public health and diagnostic medicine. PCR and culture have historically played an important role in clinical microbiology; however, these methods require a targeted approach and may lack the capacity to identify novel or mixed viral infections. High-throughput sequencing can overcome these constraints. As the cost of running multiple samples continues to decrease, the implementation of high-throughput sequencing for diagnostic purposes is becoming more feasible. Here we present a comparative analysis of findings from an investigation of unexplained febrile illness using two strategies: unbiased high-throughput sequencing and VirCapSeq-VERT, a positive selection high-throughput sequencing system

    Swiss public health measures associated with reduced SARS-CoV-2 transmission using genome data

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    Genome sequences from evolving infectious pathogens allow quantification of case introductions and local transmission dynamics. We sequenced 11,357 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genomes from Switzerland in 2020 - the sixth largest effort globally. Using a representative subset of these data, we estimated viral introductions to Switzerland and their persistence over the course of 2020. We contrasted these estimates with simple null models representing the absence of certain public health measures. We show that Switzerland's border closures de-coupled case introductions from incidence in neighboring countries. Under a simple model, we estimate an 86-98% reduction in introductions during Switzerland's strictest border closures. Furthermore, the Swiss 2020 partial lockdown roughly halved the time for sampled introductions to die out. Last, we quantified local transmission dynamics once introductions into Switzerland occurred, using a phylodynamic model. We found that transmission slowed 35-63% upon outbreak detection in summer 2020, but not in fall. This finding may indicate successful contact tracing over summer before overburdening in fall. The study highlights the added value of genome sequencing data for understanding transmission dynamics

    Geographical and temporal distribution of SARS-CoV-2 clades in the WHO European Region, January to June 2020

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    We show the distribution of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) genetic clades over time and between countries and outline potential genomic surveillance objectives. We applied three genomic nomenclature systems to all sequence data from the World Health Organization European Region available until 10 July 2020. We highlight the importance of real-time sequencing and data dissemination in a pandemic situation, compare the nomenclatures and lay a foundation for future European genomic surveillance of SARS-CoV-2

    Kinematics and Age of Syn-Intrusive Detachment Faulting in the Southern Alps: Evidence for Early Permian Crustal Extension and Implications for the Pangea A Versus B Controversy

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    Permian basin formation and magmatism in the Southern Alps of Italy have been interpreted as expressions of a WSW‐ENE‐trending, dextral megashear zone transforming Early Permian Pangea B into Late Permian Pangea A between ~285 and 265 Ma. In an alternative model, basin formation and magmatism resulted from N‐S crustal extension. To characterize Permian tectonics, we studied the Grassi Detachment Fault, a low‐angle extensional fault in the central Southern Alps. The footwall forms a metamorphic core complex affected by upward‐increasing, top‐to‐the‐southeast mylonitization. Two granitoid intrusions occur in the core complex, the synmylonitic Val Biandino Quartz Diorite and the postmylonitic Valle San Biagio Granite. U‐Pb zircon dating yielded crystallization ages of 289.1 ± 4.5 Ma for the former and 286.8 ± 4.9 Ma for the latter. Consequently, detachment‐related mylonitic shearing took place during the Early Permian and ended at ~288 Ma, but kinematically coherent brittle faulting continued. Considering 30° anticlockwise rotation of the Southern Alps since Early Permian, the extension direction of the Grassi Detachment Fault was originally ~N‐S. Even though a dextral continental wrench system has long been regarded as a viable model at regional scale, the local kinematic evidence is inconsistent with this and, rather, supports N‐S extensional tectonics. Based on a compilation of >200 U‐Pb zircon ages, we discuss the evolution and tectonic framework of Late Carboniferous to Permian magmatism in the Alps

    Interactors screen of R02F11.4, the Cep97 C. elegans homologous protein, using the yeast two hybrid system

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    Centrosomes are the microtubules organizing centers of most eukaryotice cells. Centrosomes are formed of a protein matrix called the pericentriolar material and two cylindrical shape structures formed of microtubules and associated proteins called centrioles. Centrosomes are important to ensure normal bipolar spindle formation during cell division. The daughter centriole elongates from its proximal end perpendicularly to the mother centriole. At the distal end of the new forming centriole, a complex formed of CCP110 and Cep97 stops probably the elongation by acting as distal cap. In previous work our lab has found a putative Cep97 homologous protein in C. elegans as an interactor of the multifunctional polo-like kinase 1 (PLK1). In this work we screen for interactors of the Cep97 C. elegans homologous protein R02F11.4. We have found four interactions; one homotypic interaction, an interaction with SAS-5 and interactions with two proteins which are candidates to be functional homologous of CCP110

    SCANellome: Analysis of the Genomic Diversity of Human and Non-Human Primate Anelloviruses from Metagenomics Data

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    Anelloviruses are extremely prevalent in the human population and are considered to be commensal parts of the human virome. The best-known member in humans is the Torque teno virus. Recent metagenomic next-generation sequencing investigations have helped reveal the considerable number of species and genotypes from the same genus that can be co-detected within a single individual and that this diversity increases as a function of age during the first months/years of life. As a result, to date, the bioinformatics analysis of this genetic diversity remains complex and constraining for researchers. Here, we present SCANellome, a user-friendly tool to investigate the anellome composition at the genus, species, and genotype levels of samples from metagenomics data generated by the Illumina and Nanopore platforms. SCANellome is based on an in-house up-to-date database that includes all human and non-human primate anellovirus reference sequences available on GenBank and meets the latest classification criteria established by the International Committee on Taxonomy of Viruses

    Genomic Diversity of Torque Teno Virus in Blood Samples from Febrile Paediatric Outpatients in Tanzania: A Descriptive Cohort Study

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    Torque teno virus (TTV) is considered to be an ubiquitous member of the commensal human blood virome commonly reported in mixed genotype co-infections. This study investigates the genomic diversity of TTV in blood samples from 816 febrile Tanzanian children. Metagenomic next-generation sequencing was used to screen for TTV in individual blood samples from a cohort of 816 febrile Tanzanian paediatric outpatients. For positive samples, the number of TTV species and genotypes present were evaluated. We investigate the linear relationship between individual TTV diversity and the patient age by linear regression. TTV was detected in 97.2% of sera. ORF1 analysis revealed the presence of 149 genotypes from 38 species, suggesting the presence of 13 new species. These genotypes were mostly present as co-infections with a median of 11 genotypes/subject (range: 1-71). In terms of species, we found a median of nine species/subject (range: 1-29). We further show a significant association between the diversity of co-detected TTV and the age of the subjects (pvalue < 0.0001). This study shows that significant TTV genomic diversity is acquired by the age of five and that this diversity tends to increase with age, which indicates a repetitive TTV acquisition during the first months/years of life

    Direct Dengue Virus Genome Sequencing from Antigen NS1 Rapid Diagnostic Tests: A Proof-of-Concept with the Standard Q Dengue Duo Assay

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    With nearly half of the world’s population being at risk of infection, dengue virus represents a major global health issue. The use of dengue antigen rapid diagnostic tests (Ag-RDTs) represents an alternative to PCR methods for the diagnosis of acute infections since they display excellent sensitivities and specificities and can be performed outside the laboratory. The high genetic diversity of the dengue virus genome represents a challenge for vaccine development, and the progressive expansion of this virus into previously nonendemic regions justifies the implementation of a genomic surveillance program. In this proof-of-concept study, we show the feasibility of sequencing dengue virus genomes directly from positive Ag-RDT (Standard Q Dengue Duo Test assay, n = 7) cassettes stored up to 31 days at room temperature after testing. For 5 of the 7 samples, a high number of reads were obtained allowing phylogenetic analyses to be carried out to determine not only the serotypes (dengue 1, 2, 3 and 4 were detected) but also the genotypes. Furthermore, in one sample, our unbiased metagenomic next-generation sequencing approach made it possible to detect epizootic hemorrhagic disease virus sequences, an arthropod-transmitted virus in ruminants. To conclude, as such an approach requires no cold storage or freezing of samples, dengue Ag-RDTs represent a very pragmatic and robust alternative for the genomic surveillance of dengue virus

    Viral metagenomics in the clinical realm: lessons learned from a Swiss-wide ring trial

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    Shotgun metagenomics using next generation sequencing (NGS) is a promising technique to analyze both DNA and RNA microbial material from patient samples. Mostly used in a research setting, it is now increasingly being used in the clinical realm as well, notably to support diagnosis of viral infections, thereby calling for quality control and the implementation of ring trials (RT) to benchmark pipelines and ensure comparable results. The Swiss NGS clinical virology community therefore decided to conduct a RT in 2018, in order to benchmark current metagenomic workflows used at Swiss clinical virology laboratories, and thereby contribute to the definition of common best practices. The RT consisted of two parts (increments), in order to disentangle the variability arising from the experimental compared to the bioinformatics parts of the laboratory pipeline. In addition, the RT was also designed to assess the impact of databases compared to bioinformatics algorithms on the final results, by asking participants to perform the bioinformatics analysis with a common database, in addition to using their own in-house database. Five laboratories participated in the RT (seven pipelines were tested). We observed that the algorithms had a stronger impact on the overall performance than the choice of the reference database. Our results also suggest that differences in sample preparation can lead to significant differences in the performance, and that laboratories should aim for at least 5-10 Mio reads per sample and use depth of coverage in addition to other interpretation metrics such as the percent of coverage. Performance was generally lower when increasing the number of viruses per sample. The lessons learned from this pilot study will be useful for the development of larger-scale RTs to serve as regular quality control tests for laboratories performing NGS analyses of viruses in a clinical setting
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