Publications de Tamar Kohn | EPFL Graph Search

Inactivation of SARS-CoV-2 at acidic pH is driven by partial unfolding of spike

Tamar Kohn, Aline Laetitia Schaub, Athanasios Nenes, Shannon Christa David

SARS-CoV-2, the causative agent of COVID-19, is predominantly transmitted by respiratory aerosol and contaminated surfaces. Recent studies demonstrated that aerosols can become acidic, and acidification has been proposed as decontamination method. Here, we ...

Springer Science and Business Media LLC2025

Seasonality of cyanobacteria and eukaryotes in Lake Geneva and the impacts of cyanotoxins on growth of the model ciliate Tetrahymena pyriformis

Tamar Kohn, Anna Carratala Ripolles

Toxic cyanobacteria are likely to be favored by global warming and other human impacts, posing significant threats to aquatic ecosystems. While cyanobacterial blooms in eutrophic lakes are widely investigated, the dynamics of cyanobacteria and the effects ...

Elsevier BV2025

Comparative characterization of bronchial and nasal mucus reveals key determinants of influenza A virus inhibition

Tamar Kohn, Céline Terrettaz, Aline Laetitia Schaub, Athanasios Nenes, Kalliopi Violaki, Ghislain Gilles Jean-Michel Motos, Walter Hugentobler

Differentiated primary human respiratory epithelial cells grown at air-liquid interface have become a widely used cell culture model of the human conducting airways. These cultures contain secretory cells such as goblet and club cells, which produce and se ...

American Society for Microbiology2025

Diversity of lake bacteria promotes human echovirus inactivation

Tamar Kohn, Hannes Markus Peter

Human enteric viruses can remain infective in surface waters for exten ded periods of time, posing a public health risk. Microbial activity contributes to the inactivation of waterborne enteric viruses, but while individual bacteria-virus interac tions hav ...

2025

Estimated transmission dynamics of SARS-CoV-2 variants from wastewater are unbiased and robust to differential shedding

Tamar Kohn, Timothy R. Julian

The COVID-19 pandemic has accelerated the development and adoption of wastewater-based epidemiology. Wastewater samples can provide genomic information for detecting and assessing the spread of SARS-CoV-2 variants in communities and for estimating importan ...

2025

Conserved specificity of extracellular wastewater peptidases revealed by multiplex substrate profiling by mass spectrometry

Tamar Kohn

Peptide-based chemicals are promising for numerous applications including home and personal care and medical treatments. To better understand and control the environmental fate of peptide-based chemicals, in-depth knowledge on the specificity of wastewater ...

Springer Science and Business Media LLC2025

Transmission dynamics of Norovirus GII and Enterovirus in Switzerland during the COVID-19 pandemic (2021-2022) as evidenced in wastewater

Tamar Kohn, Htet Kyi Wynn, Timothy R. Julian, Shotaro Torii

Noroviruses and enteroviruses are major causes of endemic gastrointestinal disease associated with substantial disease burden. However, viral gastroenteritis is often diagnosed based on symptoms, with etiology infrequently tested or reported, so little inf ...

Elsevier BV2025

The early communication stages between serine proteases and enterovirus capsids in the race for viral disintegration

Diego Chiappe, Tamar Kohn, Shannon Christa David, Shotaro Torii

Serine proteases are important environmental contributors of enterovirus biocontrol. However, the structural features of molecular interaction accounting for the susceptibility of enteroviruses to proteases remains unexplained. Here, we describe the molecu ...

Springer Science and Business Media LLC2024

Dependence of aerosol-borne influenza A virus infectivity on relative humidity and aerosol composition

Tamar Kohn, Céline Terrettaz, Aline Laetitia Schaub, Athanasios Nenes, Kalliopi Violaki, Shannon Christa David, Ghislain Gilles Jean-Michel Motos, Walter Hugentobler, Laura José Costa Henriques

We describe a novel biosafety aerosol chamber equipped with state-of-theart instrumentation for bubble-bursting aerosol generation, size distribution measurement, and condensation-growth collection to minimize sampling artifacts when measuring virus infect ...

Frontiers Media SA2024

Salt Supersaturation as an Accelerator of Influenza A Virus Inactivation in 1 μL Droplets

Tamar Kohn, Céline Terrettaz, Athanasios Nenes, Kalliopi Violaki, Ghislain Gilles Jean-Michel Motos, Walter Hugentobler, Laura José Costa Henriques

Influenza A virus (IAV) spreads through exhaled aerosol particles and larger droplets. Estimating the stability of IAV is challenging and depends on factors such as the respiratory matrix and drying kinetics. Here, we combine kinetic experiments on millime ...

2024

Monitoring an Emergent Pathogen at Low Incidence in Wastewater Using qPCR: Mpox in Switzerland

Tamar Kohn, Timothy R. Julian

Wastewater-based epidemiology offers a complementary approach to clinical case-based surveillance of emergent diseases and can help identify regions with infected people to prioritize clinical surveillance strategies. However, tracking emergent diseases in ...

2024

Comparison of Three Viral Nucleic Acid Preamplification Pipelines for Sewage Viral Metagenomics

Tamar Kohn, Xavier Fernandez Cassi

Viral metagenomics is a useful tool for detecting multiple human viruses in urban sewage. However, more refined protocols are required for its effective use in disease surveillance. In this study, we investigated the performance of three different preampli ...

2024

Waterborne Virus Transport and Risk Assessment in Lake Geneva Under Climate Change

Tamar Kohn, Chaojie Li

Climate changes influence lake hydrodynamics and radiation levels and thus may affect the fate and transport of waterborne pathogens in lakes. This study examines the impact of climate change on the fate, transport, and associated risks of four waterborne ...

2024

Influence of Amino Acid Substitutions in Capsid Proteins of Coxsackievirus B5 on Free Chlorine and Thermal Inactivation

Tamar Kohn, Shotaro Torii, Aleksandar Antanasijevic, Kiruthika Kumar

The sensitivity of enteroviruses to disinfectants varies among genetically similar variants and coincides with amino acid changes in capsid proteins, although the effect of individual substitutions remains unknown. Here, we employed reverse genetics to inv ...

2024

Stability of influenza A virus in droplets and aerosols is heightened by the presence of commensal respiratory bacteria

Tamar Kohn, Htet Kyi Wynn, Céline Terrettaz, Aline Laetitia Schaub, Athanasios Nenes, Kalliopi Violaki, Marta Augugliaro, Shannon Christa David, Ghislain Gilles Jean-Michel Motos, Walter Hugentobler, Laura José Costa Henriques, Daniel Scott Nolan

Aerosol transmission remains a major challenge for control of respiratory viruses, particularly those causing recurrent epidemics, like influenza A virus (IAV). These viruses are rarely expelled alone, but instead are embedded in a consortium of microorgan ...

American Society for Microbiology2024

Impact of organic compounds on the stability of influenza A virus in deposited 1-μL droplets

Tamar Kohn, Céline Terrettaz, Aline Laetitia Schaub, Athanasios Nenes, Kalliopi Violaki, Shannon Christa David, Ghislain Gilles Jean-Michel Motos, Walter Hugentobler

The composition of respiratory fluids influences the stability of viruses in exhaled aerosol particles and droplets, though the role of respiratory organics in modulating virus stability remains poorly understood. This study investigates the effect of orga ...

2024

Inactivation mechanisms of influenza A virus under pH conditions encountered in aerosol particles as revealed by whole-virus HDX-MS

Tamar Kohn, Jonathan Paz Montoya, Aline Laetitia Schaub, Athanasios Nenes, Giovanni D'Angelo, Kalliopi Violaki, Shannon Christa David, Ghislain Gilles Jean-Michel Motos, Walter Hugentobler

Multiple respiratory viruses, including influenza A virus (IAV), can be transmitted via expiratory aerosol particles, and aerosol pH was recently identified as a major factor influencing airborne virus infectivity. Indoors, small exhaled aerosols undergo r ...

2023

Uptake without inactivation of human adenovirus type 2 by Tetrahymena pyriformis ciliates

Tamar Kohn, Margot Ninon Lauren Olive

Human adenoviruses are ubiquitous contaminants of surface water. Indigenous protists may interact with adenoviruses and contribute to their removal from the water column, though the associated kinetics and mechanisms differ between protist species. In this ...

2023

Expiratory Aerosol pH: The Overlooked Driver of Airborne Virus Inactivation

Tamar Kohn, Aline Laetitia Schaub, Athanasios Nenes, Kalliopi Violaki, Shannon Christa David, Ghislain Gilles Jean-Michel Motos, Walter Hugentobler

Respiratory viruses, including influenza virus and SARS-CoV-2, are transmitted by the airborne route. Air filtration and ventilation mechanically reduce the concentration of airborne viruses and are necessary tools for disease mitigation. However, they ign ...

2023

Vertical distribution and seasonal dynamics of planktonic cyanobacteria communities in a water column of deep mesotrophic Lake Geneva

Natacha Tofield-Pasche, Stéphane Joost, Tamar Kohn, Charlotte Gisèle Weil, Oliver Michele Selmoni, Anna Carratala Ripolles, Coralie Chappelier, Hannah Elisa Chmiel, Annie Sandrine Guillaume

Background: Temperate subalpine lakes recovering from eutrophication in central Europe are experiencing harmful blooms due to the proliferation of Planktothrix rubescens, a potentially toxic cyanobacteria. To optimize the management of cyanobacteria blooms ...

Frontiers Media SA2023