Publications by authors named "Kristian Andersen"

Article Synopsis
  • Zoonotic viruses, like SARS-CoV-2, can spill over from animals to humans, often linked to animal trade, with COVID-19 traced back to the Huanan Seafood Wholesale Market.
  • Analysis of environmental samples from the market in early 2020 shows high genetic diversity of SARS-CoV-2, especially near a wildlife stall that had a variety of wildlife DNA, including potential intermediate hosts.
  • The research combines genomic techniques to identify specific animal species and suggest which ones should be prioritized for further research on their role in transmitting the virus.
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  • - Lassa virus, which is linked to thousands of deaths annually, primarily spreads from Mastomys rodents to humans, highlighting the need for effective vaccines and treatments.
  • - Researchers conducted experiments using pseudovirus deep mutational scanning to analyze mutations in the virus's glycoprotein complex (GPC) that impact its ability to enter cells and be neutralized by antibodies.
  • - The study identified how mutations in GPC can escape neutralization by existing antibodies and proposed a method to better understand these variations, which could improve the development of future vaccines and therapies.
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  • Nigeria reported its first mpox cases in nearly 40 years five years before the 2022-2023 outbreak, with ongoing human-to-human transmission driving the epidemic.
  • Researchers analyzed 112 mpox virus genomes from Nigeria (2021-2023) and traced the lineage back to its emergence around July 2014 from southern Nigeria, specifically Rivers State.
  • The study also found that human-to-human transmission significantly increased the virus's evolutionary rate and emphasized the importance of better pathogen surveillance and response strategies.
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  • Nigeria and Cameroon reported their first mpox cases in over 30 years starting in 2017 and 2018, with Nigeria's outbreak recognized as a human epidemic.
  • The study focused on understanding the zoonotic transmission dynamics of the mpox virus across the Nigeria-Cameroon border, revealing ongoing cases driven by a new Clade IIb.1 lineage and highlighting significant cross-border viral spread.
  • The findings indicate that southern Nigeria is likely the origin of the mpox epidemic, with evidence of a zoonotic precursor lineage present in local animal populations for over 45 years, emphasizing the persistent risk of MPXV emergence in both countries.
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The immunological signatures driving the severity of coronavirus disease 19 (COVID-19) in Ghanaians remain poorly understood. We performed bulk transcriptome sequencing of nasopharyngeal samples from severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-infected Ghanaians with mild and severe COVID-19, as well as healthy controls to characterize immune signatures at the primary SARS-CoV-2 infection site and identify drivers of disease severity. Generally, a heightened antiviral response was observed in SARS-CoV-2-infected Ghanaians compared with uninfected controls.

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Lassa virus is estimated to cause thousands of human deaths per year, primarily due to spillovers from its natural host, rodents. Efforts to create vaccines and antibody therapeutics must account for the evolutionary variability of Lassa virus's glycoprotein complex (GPC), which mediates viral entry into cells and is the target of neutralizing antibodies. To map the evolutionary space accessible to GPC, we use pseudovirus deep mutational scanning to measure how nearly all GPC amino-acid mutations affect cell entry and antibody neutralization.

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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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Background: Allergic rhinitis with or without conjunctivitis can negatively impact many aspects of quality of life (QoL). The efficacy and safety of standardized quality (SQ) sublingual immunotherapy (SLIT) tablets have been confirmed across large clinical trials in adults with grass, tree, ragweed, and house dust mite (HDM) allergic rhinitis with or without conjunctivitis.

Objective: This pooled analysis investigates whether the reduction in symptom burden found across the clinical trials is supported by improvements in QoL.

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In the United States (US), biosafety and biosecurity oversight of research on viruses is being reappraised. Safety in virology research is paramount and oversight frameworks should be reviewed periodically. Changes should be made with care, however, to avoid impeding science that is essential for rapidly reducing and responding to pandemic threats as well as addressing more common challenges caused by infectious diseases.

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The maturation of genomic surveillance in the past decade has enabled tracking of the emergence and spread of epidemics at an unprecedented level. During the COVID-19 pandemic, for example, genomic data revealed that local epidemics varied considerably in the frequency of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lineage importation and persistence, likely due to a combination of COVID-19 restrictions and changing connectivity. Here, we show that local COVID-19 epidemics are driven by regional transmission, including across international boundaries, but can become increasingly connected to distant locations following the relaxation of public health interventions.

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The COVID-19 pandemic has profoundly impacted health systems globally and robust surveillance has been critical for pandemic control, however not all countries can currently sustain community pathogen surveillance programs. Wastewater surveillance has proven valuable in high-income settings, but less is known about the utility of water surveillance of pathogens in low-income countries. Here we show how wastewater surveillance of SAR-CoV-2 can be used to identify temporal changes and help determine circulating variants quickly.

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Lassa virus (LASV), Junin virus (JUNV), and several other members of the Arenaviridae family are capable of zoonotic transfer to humans and induction of severe viral hemorrhagic fevers. Despite the importance of arenaviruses as potential pandemic pathogens, numerous gaps exist in scientific knowledge pertaining to this diverse family, including gaps in understanding replication, immunosuppression, receptor usage, and elicitation of neutralizing antibody responses, that in turn complicates development of medical countermeasures. A further challenge to the development of medical countermeasures for arenaviruses is the requirement for use of animal models at high levels of biocontainment, where each model has distinct advantages and limitations depending on, availability of space, animals species-specific reagents, and most importantly the ability of the model to faithfully recapitulate human disease.

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As global SARS-CoV-2 burden and testing frequency have decreased, wastewater surveillance has emerged as a key tool to support clinical surveillance efforts. The aims of this study were to identify and characterize SARS-CoV-2 variants in wastewater samples collected from urban centers across South Africa. Here we show that wastewater sequencing analyses are temporally concordant with clinical genomic surveillance and reveal the presence of multiple lineages not detected by clinical surveillance.

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Article Synopsis
  • Zoonotic virus spillovers, including the COVID-19 pandemic, are linked to animal trade, with the Huanan Seafood Market in Wuhan being a focal point of investigation.
  • Analysis of environmental samples from this market showed a specific wildlife stall with high SARS-CoV-2 positivity and identified various animal DNA, including raccoon dogs, which can transmit the virus.
  • The study used genetic data to suggest potential intermediate hosts for SARS-CoV-2, aiming to guide future testing and viral sampling efforts.
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The COVID-19 pandemic continues to impact health systems globally and robust surveillance is critical for pandemic control, however not all countries can sustain community surveillance programs. Wastewater surveillance has proven valuable in high-income settings, but little is known about how river and informal sewage in low-income countries can be used for environmental surveillance of SARS-CoV-2. In Malawi, a country with limited community-based COVID-19 testing capacity, we explored the utility of rivers and wastewater for SARS-CoV-2 surveillance.

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Article Synopsis
  • * A study conducted in Sierra Leone between November 2018 and July 2019 involved trapping small mammals and using tests to detect Lassa virus (LASV) antigens and antibodies in order to understand the virus's prevalence in the area.
  • * Out of 373 rodents tested, 20% were positive for the LASV antigen, while 11% showed the presence of antibodies, indicating that the tools developed could enhance public health efforts in tracking and managing Lassa fever outbreaks.
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Whereas cardiomyocytes (CMs) in the fetal heart divide, postnatal CMs fail to undergo karyokinesis and/or cytokinesis and therefore become polyploid or binucleated, a key process in terminal CM differentiation. This switch from a diploid proliferative CM to a terminally differentiated polyploid CM remains an enigma and seems an obstacle for heart regeneration. Here, we set out to identify the transcriptional landscape of CMs around birth using single cell RNA sequencing (scRNA-seq) to predict transcription factors (TFs) involved in CM proliferation and terminal differentiation.

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  • The global scientific community has sequenced over 11 million SARS-CoV-2 genomes by May 2022, allowing real-time tracking of virus evolution.
  • Outbreak.info is a platform that monitors over 40 million variants and mutations across 7,000 locations, providing valuable insights for researchers and public health officials.
  • The platform features user-friendly visualizations and robust infrastructure for data ingestion and dissemination, supporting genomic surveillance and hypothesis generation regarding the pandemic.
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Outbreak.info Research Library is a standardized, searchable interface of coronavirus disease 2019 (COVID-19) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) publications, clinical trials, datasets, protocols and other resources, built with a reusable framework. We developed a rigorous schema to enforce consistency across different sources and resource types and linked related resources.

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  • The study focuses on the emergence and dissemination patterns of the SARS-CoV-2 B.1.1.318 and B.1.525 (Eta) variants in Nigeria and Africa, highlighting their significance for public health policies during a pandemic.
  • By combining genomic and travel data, the research indicates that both variants originated from within Africa, with B.1.525 emerging specifically in Nigeria before spreading globally.
  • The findings emphasize the importance of understanding regional connectivity and bidirectional transmission in Africa, revealing that the risks of virus importation between countries have been underestimated.
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RNA viruses have short generation times and high mutation rates, allowing them to undergo rapid molecular evolution during epidemics. However, the extent of RNA virus phenotypic evolution within epidemics and the resulting effects on fitness and virulence remain mostly unknown. Here, we screened the 2015-2016 Zika epidemic in the Americas for lineage-specific fitness differences.

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Wastewater contains information on pathogen spread, evolution, and outbreak risk.

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Lassa fever is a severe viral hemorrhagic fever caused by a zoonotic virus that repeatedly spills over to humans from its rodent reservoirs. It is currently not known how climate and land use changes could affect the endemic area of this virus, currently limited to parts of West Africa. By exploring the environmental data associated with virus occurrence using ecological niche modelling, we show how temperature, precipitation and the presence of pastures determine ecological suitability for virus circulation.

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Regional connectivity and land travel have been identified as important drivers of SARS-CoV-2 transmission. However, the generalizability of this finding is understudied outside of well-sampled, highly connected regions. In this study, we investigated the relative contributions of regional and intercontinental connectivity to the source-sink dynamics of SARS-CoV-2 for Jordan and the Middle East.

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