Publications by authors named "Stalder H"

Bovine viral diarrhea virus (BVDV), a pestivirus in the family , is a major livestock pathogen. Horizontal transmission leads to acute transient infections via the oronasal route, whereas vertical transmission might lead to the birth of immunotolerant, persistently infected animals. In both cases, BVDV exerts an immunosuppressive effect, predisposing infected animals to secondary infections.

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Article Synopsis
  • - Approved vaccines are good for preventing severe COVID-19, but new variants and transmission need a stronger immune response, leading to the creation of modified live-attenuated vaccines (LAVs) that recode the SARS-CoV-2 genome.
  • - The new vaccines, called OTS-206 and OTS-228, are designed to be safe and effective, with OTS-228 showing no side effects or transmission in animal studies, and can be given intranasally.
  • - A single dose of OTS-228 not only provides strong immunity against the original SARS-CoV-2 strain but also offers broad protection against variants like Omicron, making this approach potentially valuable for other emerging viruses as well. *
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Feline infectious peritonitis (FIP) is a fatal feline disease, caused by a feline coronavirus (FCoV), namely feline infectious peritonitis virus (FIPV). We produced a baby hamster kidney 21 (BHK) cell line expressing a serotype I FCoV replicon RNA with a green fluorescent protein (GFP) reporter gene (BHK-F-Rep) and used it as an screening system to test different antiviral compounds. Two inhibitors of the FCoV main protease (M), namely GC376 and Nirmatrelvir, as well as the nucleoside analog Remdesivir proved to be effective in inhibiting the replicon system.

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Porcine epidemic diarrhea virus is a swine pathogen that has been responsible for significant animal and economic losses worldwide in recent years. In this manuscript, we report the generation of a reverse genetics system C(RGS) for the highly virulent US PEDV strain Minnesota (PEDV-MN; GenBank accession number KF468752), which was based on the assembly and cloning of synthetic DNA, using vaccinia virus as a cloning vector. Viral rescue was only possible following the substitution of 2 nucleotides within the 5'UTR and 2 additional nucleotides within the spike gene, based on the sequence of the cell culture-adapted strains.

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  • The Omicron-BA.1 variant of concern became the dominant strain globally in early 2022, prompting the need for extensive research using primary cell cultures and animal models to understand its characteristics compared to the Delta variant.* -
  • In laboratory studies, Omicron-BA.1 showed increased early replication in human nasal cells but less replication in bronchial cells; however, in animal models like hamsters and ferrets, Delta variant remained more dominant.* -
  • The research revealed that the spike gene from Omicron-BA.1 leads to lower replication and pathogenicity in certain mice, while also indicating that this variant may escape immune responses generated by mRNA vaccines, contributing to its dominance over other variants.*
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In 2012, Middle East respiratory syndrome coronavirus (MERS-CoV) emerged in Saudi Arabia and was mostly associated with severe respiratory illness in humans. Dromedary camels are the zoonotic reservoir for MERS-CoV. To investigate the biology of MERS-CoV in camelids, we developed a well-differentiated airway epithelial cell (AEC) culture model for Llama glama and Camelus bactrianus.

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Bovine viral diarrhoea virus (BVDV) and Border disease virus (BDV) are closely related pestiviruses of cattle and sheep, respectively. Both viruses may be transmitted between either species, but control programs are restricted to BVDV in cattle. In 2008, a program to eradicate bovine viral diarrhoea (BVD) in cattle was started in Switzerland.

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Bovine viral diarrhoea virus (BVDV) and related ruminant pestiviruses occur worldwide and cause considerable economic losses in livestock and severely impair animal welfare. Switzerland started a national mandatory control programme in 2008 aiming to eradicate BVD from the Swiss cattle population. The peculiar biology of pestiviruses with the birth of persistently infected (PI) animals upon infection in addition to transient infection of naïve animals requires vertical and horizontal transmission to be taken into account.

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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread globally, and the number of worldwide cases continues to rise. The zoonotic origins of SARS-CoV-2 and its intermediate and potential spillback host reservoirs, besides humans, remain largely unknown. Because of ethical and experimental constraints and more important, to reduce and refine animal experimentation, we used our repository of well-differentiated airway epithelial cell (AEC) cultures from various domesticated and wildlife animal species to assess their susceptibility to SARS-CoV-2.

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Since the emergence of coronavirus disease (COVID-19) in late 2019, domestic cats have been demonstrated to be susceptible to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) under natural and experimental conditions. As pet cats often live in very close contact with their owners, it is essential to investigate SARS-CoV-2 infections in cats in a One-Health context. This study reports the first SARS-CoV-2 infection in a cat in a COVID-19-affected household in Switzerland.

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Article Synopsis
  • SARS-CoV-2, identified in late 2019, has quickly become a global public health issue due to its higher transmission rates compared to its relative SARS-CoV.
  • Research indicates that the temperature in different parts of the respiratory system (33°C in the upper tract vs. 37°C in the lower tract) influences how effectively both viruses replicate.
  • At 33°C, SARS-CoV-2 shows increased replication rates and distinct immune response patterns, providing insights into its behavior and the factors influencing its spread and clinical symptoms.
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  • * Research shows that the D614G variant binds more effectively to the ACE2 receptor and replicates better in human airway cells and animal models compared to other variants.
  • * The study concludes that the D614G mutation gives the virus a competitive advantage in transmission, helping to explain its widespread prevalence globally.
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  • - The D614G substitution in the SARS-CoV-2 spike protein became the dominant variant during the COVID-19 pandemic, but its advantages in replication and transmission were unclear.
  • - Research shows that the S-614G variant binds more effectively to human ACE2 and replicates better in human airway cultures and animal models.
  • - The findings indicate that the S-614G variant offers a competitive edge, especially during transmission phases, explaining its spread and prevalence globally.
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  • - The SARS-CoV-2 pandemic is the third significant zoonotic coronavirus to impact humans, following earlier outbreaks of SARS-CoV and MERS-CoV, which underscored the urgent need for effective treatments and prevention methods that still remain elusive.
  • - Understanding the molecular and cellular mechanisms behind coronavirus infections is crucial for identifying potential targets for antiviral drugs and for comprehending key factors that contribute to severe disease outcomes.
  • - This Review discusses recent findings about the lifecycle of SARS-CoV-2 and contrasts it with other coronaviruses, which can enhance our preparedness and strategies for tackling future coronavirus threats.
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Background: Serological immunoassays that can identify protective immunity against SARS-CoV-2 are needed to adapt quarantine measures, assess vaccination responses, and evaluate donor plasma. To date, however, the utility of such immunoassays remains unclear. In a mixed-design evaluation study, we compared the diagnostic accuracy of serological immunoassays that are based on various SARS-CoV-2 proteins and assessed the neutralizing activity of antibodies in patient sera.

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Zoonotic coronaviruses (CoVs) are substantial threats to global health, as exemplified by the emergence of two severe acute respiratory syndrome CoVs (SARS-CoV and SARS-CoV-2) and Middle East respiratory syndrome CoV (MERS-CoV) within two decades. Host immune responses to CoVs are complex and regulated in part through antiviral interferons. However, interferon-stimulated gene products that inhibit CoVs are not well characterized.

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Zoonotic coronaviruses (CoVs) are significant threats to global health, as exemplified by the recent emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) . Host immune responses to CoV are complex and regulated in part through antiviral interferons. However, the interferon-stimulated gene products that inhibit CoV are not well characterized .

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Bovine viral diarrhoea virus (BVDV) is a pestivirus that affects both cattle and sheep, causing an array of clinical signs, which include abortions and malformations in the offspring. Manufacturing of modified live virus (MLV) vaccines often includes the use of bovine-derived products, which implies a risk of contamination with viable BVDV. Recently, the circulation of a specific strain of BVDV 2b among Spanish sheep flocks, associated with outbreaks of abortions and malformations, and whose origin was not determined, has been observed.

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  • Reverse genetics is crucial for understanding viral behavior and developing vaccines, but working with large RNA viruses like coronaviruses is challenging due to their size and stability issues.
  • A new yeast-based synthetic genomics platform allows researchers to reconstruct various RNA viruses by assembling viral DNA fragments in yeast, streamlining the cloning process.
  • This method enabled the rapid engineering of SARS-CoV-2 clones in just a week, which could significantly improve responses to new virus outbreaks by allowing for quick analysis of emerging variants.
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Thirteen epimeric pairs of 5-substituted N-piperonyl-3-phenylpiperidine derivatives were synthesized in order to explore the stereospecific modulation of basicity, lipophilicity, aqueous solubility, and membrane permeation by functional groups in equatorial or axial positions beta to the amine unit. While this comprehensive data set provides enhanced insight into multiple factors that affect basicity and lipophilicity, it fills an important knowledge gap, providing a frame of reference for the property-based design of bioactive compounds. Impacts on amine basicity are very pronounced for the β-equatorial functional groups and parallel basicity-lowering effects known for acyclic amine derivatives.

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In 2015, a new pestivirus was described in pig sera in the United States. This new "atypical porcine pestivirus" (APPV) was later associated with congenital tremor (CT) in newborn piglets. The virus appears to be distributed worldwide, but the limited knowledge of virus diversity and the use of various diagnostic tests prevent direct comparisons.

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Influenza viruses are notorious pathogens that frequently cross the species barrier with often severe consequences for both animal and human health. In 2011, a novel member of the family, Influenza D virus (IDV), was identified in the respiratory tract of swine. Epidemiological surveys revealed that IDV is distributed worldwide among livestock and that IDV-directed antibodies are detected in humans with occupational exposure to livestock.

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Positive-sense RNA viruses hijack intracellular membranes that provide niches for viral RNA synthesis and a platform for interactions with host proteins. However, little is known about host factors at the interface between replicase complexes and the host cytoplasm. We engineered a biotin ligase into a coronaviral replication/transcription complex (RTC) and identified >500 host proteins constituting the RTC microenvironment.

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The first records of smallpox and rabies date back thousands of years and foot-and-mouth disease in cattle was described in the 16th century. These diseases stood out by their distinct signs, dramatic way of transmission from rabid dogs to humans, and sudden appearance in cattle herds. By contrast, infectious diseases that show variable signs and affect few individuals were identified only much later.

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The virus family encompasses several viruses, including (re)emerging viruses which cause widespread morbidity and mortality throughout the world. Members of this virus family are positive-strand RNA viruses and replicate their genome in close association with reorganized intracellular host cell membrane compartments. This evolutionarily conserved strategy facilitates efficient viral genome replication and contributes to evasion from host cell cytosolic defense mechanisms.

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