Publications by authors named "Schaffner S"

Summary: In viral genomic research and surveillance, inter-sample contamination can affect variant detection, analysis of within-host evolution, outbreak reconstruction, and detection of superinfections and recombination events. While sample barcoding methods exist to track inter-sample contamination, they are not always used and can only detect contamination in the experimental pipeline from the point they are added. The underlying genomic information in a sample, however, carries information about inter-sample contamination occurring at any stage.

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Pathogen genomics is a powerful tool for tracking infectious disease transmission. In malaria, identity-by-descent (IBD) is used to assess the genetic relatedness between parasites and has been used to study transmission and importation. In theory, IBD can be used to distinguish genealogical relationships to reconstruct transmission history or identify parasites for quantitative-trait-locus experiments.

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The RWI-GEO-VOTE dataset was collected to understand how the refugee inflows affected the vote share of parties in the 2017 German federal election. The dataset provides granular insights into the 2017 German federal election at the 1 km x 1 km grid cell level. Compiled by the Research Data Center (FDZ) Ruhr at RWI, it covers 175,758 grid cells and provides data on valid votes for all parties that could be elected.

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Vaccination is a highly effective method to prevent the spread of COVID-19 and mitigate severe disease. In Germany, adult vaccination rates are relatively high at 85.5%, but rates are significantly lower for adolescents (69.

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Pathogen genomics is a powerful tool for tracking infectious disease transmission. In malaria, identity-by-descent (IBD) is used to assess the genetic relatedness between parasites and has been used to study transmission and importation. In theory, IBD can be used to distinguish genealogical relationships to reconstruct transmission history or identify parasites for genotype-to-phenotype quantitative-trait-locus experiments.

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Background: Drug resistance in Plasmodium falciparum is a major threat to malaria control efforts. Pathogen genomic surveillance could be invaluable for monitoring current and emerging parasite drug resistance.

Methods: Data from two decades (2000-2020) of continuous molecular surveillance of P.

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Reproductive status, such as pregnancy and menopause in women, profoundly influences metabolism of the body. Mitochondria likely orchestrate many of these metabolic changes. However, the influence of reproductive status on somatic mitochondria and the underlying mechanisms remain largely unexplored.

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Article Synopsis
  • The RTS,S/AS01 malaria vaccine was tested for its effectiveness in a study involving 1,500 children aged 5-17 months in Ghana and Kenya, focusing on different dosing regimens.
  • Four different groups received the vaccine in varying full and fractional doses, while a control group got a rabies vaccine.
  • Results showed all RTS,S/AS01 regimens provided similar vaccine efficacy (25-43%) against new malaria infections, significantly reducing the number of infections over a 20-month follow-up period.
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  • The study investigates how sex, genetics, and pesticide exposure impact the risk of sporadic Parkinson's disease (PD), emphasizing that these factors together may influence epigenetic changes associated with PD.
  • Analyzing blood DNA methylation patterns in agricultural workers, the research found significantly more associations in females compared to males, highlighting 69 regions in females versus only 2 in males.
  • The study suggests that genetic factors and their interaction with pesticide exposure play important roles in explaining differences in DNA methylation related to PD, indicating a need for further research with larger populations and better exposure measurements.
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  • Genetic surveillance of Plasmodium falciparum can help National Malaria Control Programmes estimate parasite transmission using metrics like multi-strain infections and infection complexity, despite uncertainties about their ability to directly predict clinical incidence.
  • In a study involving 3,147 clinical infections across Senegal from 2012-2020, researchers used genetic analysis to correlate genetic metrics with malaria incidence at different clinic sites.
  • Results indicated that genetic metrics reliably predicted incidence when transmission was high (over 10 cases per 1,000 annually), but showed reversed correlations at lower transmission levels, suggesting a limit to the use of genetics in estimating incidence during low transmission periods.
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Infection with Lassa virus (LASV) can cause Lassa fever, a haemorrhagic illness with an estimated fatality rate of 29.7%, but causes no or mild symptoms in many individuals. Here, to investigate whether human genetic variation underlies the heterogeneity of LASV infection, we carried out genome-wide association studies (GWAS) as well as seroprevalence surveys, human leukocyte antigen typing and high-throughput variant functional characterization assays.

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The worldwide decline in malaria incidence is revealing the extensive burden of non-malarial febrile illness (NMFI), which remains poorly understood and difficult to diagnose. To characterize NMFI in Senegal, we collected venous blood and clinical metadata in a cross-sectional study of febrile patients and healthy controls in a low malaria burden area. Using 16S and untargeted sequencing, we detected viral, bacterial, or eukaryotic pathogens in 23% (38/163) of NMFI cases.

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Background: The only licensed malaria vaccine, RTS,S/AS01 , confers moderate protection against symptomatic disease. Because many malaria infections are asymptomatic, we conducted a large-scale longitudinal parasite genotyping study of samples from a clinical trial exploring how vaccine dosing regimen affects vaccine efficacy (VE).

Methods: 1,500 children aged 5-17 months were randomized to receive four different RTS,S/AS01 regimens or a rabies control vaccine in a phase 2b clinical trial in Ghana and Kenya.

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Genetic surveillance of the parasite shows great promise for helping National Malaria Control Programs (NMCPs) assess parasite transmission. Genetic metrics such as the frequency of polygenomic (multiple strain) infections, genetic clones, and the complexity of infection (COI, number of strains per infection) are correlated with transmission intensity. However, despite these correlations, it is unclear whether genetic metrics alone are sufficient to estimate clinical incidence.

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We here analyze data from the first year of an ongoing nationwide program of genetic surveillance of Plasmodium falciparum parasites in Senegal. The analysis is based on 1097 samples collected at health facilities during passive malaria case detection in 2019; it provides a baseline for analyzing parasite genetic metrics as they vary over time and geographic space. The study's goal was to identify genetic metrics that were informative about transmission intensity and other aspects of transmission dynamics, focusing on measures of genetic relatedness between parasites.

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While genome-wide association studies (GWAS) and positive selection scans identify genomic loci driving human phenotypic diversity, functional validation is required to discover the variant(s) responsible. We dissected the IVD gene locus-which encodes the isovaleryl-CoA dehydrogenase enzyme-implicated by selection statistics, multiple GWAS, and clinical genetics as important to function and fitness. We combined luciferase assays, CRISPR/Cas9 genome-editing, massively parallel reporter assays (MPRA), and a deletion tiling MPRA strategy across regulatory loci.

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Genome sequencing can offer critical insight into pathogen spread in viral outbreaks, but existing transmission inference methods use simplistic evolutionary models and only incorporate a portion of available genetic data. Here, we develop a robust evolutionary model for transmission reconstruction that tracks the genetic composition of within-host viral populations over time and the lineages transmitted between hosts. We confirm that our model reliably describes within-host variant frequencies in a dataset of 134,682 SARS-CoV-2 deep-sequenced genomes from Massachusetts, USA.

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Histone modifications are critical for regulating chromatin structure and gene expression. Dysregulation of histone modifications likely contributes to disease states and cancer. Depletion of the chromatin-binding protein BRWD3 (Bromodomain and WD repeat-containing protein 3), a known substrate-specificity factor of the Cul4-DDB1 E3 ubiquitin ligase complex, results in increased H3K4me1 (H3 lysine 4 monomethylation) levels.

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Article Synopsis
  • Researchers studied non-malarial febrile illness (NMFI) in Senegal, finding it is hard to understand and diagnose.
  • In their study, they found that 29% of NMFI cases had different germs, mostly bacteria, while some cases had viruses.
  • They created a model to help doctors better identify NMFI based on symptoms and health signs, showing that better testing is really needed.
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Elevated alpha-synuclein (SNCA) gene expression is associated with transcriptional deregulation and increased risk of Parkinson's disease, which may be partially ameliorated by environmental enrichment. At the molecular level, there is emerging evidence that excess alpha-synuclein protein (aSyn) impacts the epigenome through direct and/or indirect mechanisms. However, the extents to which the effects of both aSyn and the environment converge at the epigenome and whether epigenetic alterations underpin the preventive effects of environmental factors on transcription remain to be elucidated.

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Effective infectious disease surveillance in high-risk regions is critical for clinical care and pandemic preemption; however, few clinical diagnostics are available for the wide range of potential human pathogens. Here, we conduct unbiased metagenomic sequencing of 593 samples from febrile Nigerian patients collected in three settings: i) population-level surveillance of individuals presenting with symptoms consistent with Lassa Fever (LF); ii) real-time investigations of outbreaks with suspected infectious etiologies; and iii) undiagnosed clinically challenging cases. We identify 13 distinct viruses, including the second and third documented cases of human blood-associated dicistrovirus, and a highly divergent, unclassified dicistrovirus that we name human blood-associated dicistrovirus 2.

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Article Synopsis
  • Drug resistance to malaria is a big problem that makes it hard to control the disease, especially in Senegal.
  • Researchers studied data from 2000 to 2020 to see how changes in medicine policies affected malaria parasites.
  • They found that when certain drugs were removed or introduced, the parasites changed quickly, showing that we need to watch how well preventive treatments work.
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  • Scientists are studying how to use parasite genetics to help control malaria in Senegal.
  • They discovered that having multiple different types of parasites in one person can predict local malaria outbreaks.
  • Most related parasites in the country form a big family, which could help identify where malaria is spreading and if certain drugs are becoming less effective against it.
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Epigenetic modifications provide powerful means for transmitting information from parent to progeny. As a maternally inherited genome that encodes essential components of the electron transport chain, the mitochondrial genome (mtDNA) is ideally positioned to serve as a conduit for the transgenerational transmission of metabolic information. Here, we provide evidence that mtDNA of contains the epigenetic mark N6-methyldeoxyadenosine (6mA).

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Article Synopsis
  • Histone modifications play a key role in gene expression and chromatin structure, and their dysregulation can lead to diseases like cancer.
  • The depletion of the chromatin-binding protein BRWD3 leads to increased H3K4me1 levels and decreased H3K4me3 levels, suggesting a broader influence on H3K4 methylation.
  • BRWD3 interacts with the demethylase KDM5 to promote its degradation, which is crucial for maintaining the balance of H3K4 methylation marks in the genome.
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