Complete Genome Sequences of Three Border Disease Virus Strains of the Same Subgenotype, BDSwiss, Isolated from Sheep, Cattle, and Pigs in Switzerland.

We report here the complete genome sequences of three border disease virus (BDV) strains of the same subgenotype isolated in Switzerland from a sheep, a cow, and a pig, respectively. This is the first report of full-length sequences of a tentatively new subgenotype isolated from three different species of cloven-hoofed farm animals.

Heterogeneous antigenic properties of the porcine reproductive and respiratory syndrome virus nucleocapsid.

Porcine reproductive and respiratory syndrome virus (PRRSV) is an arterivirus responsible for a widespread contagious disease of domestic pigs with high economic impact. Switzerland is one of the rare PRRSV-free countries in Europe, although sporadic outbreaks have occurred in the past. The PRRSV isolate IVI-1173 from the short outbreak in Switzerland in 2012 was entirely sequenced, and a functional full-length cDNA clone was constructed.

Intracellular membrane association of the N-terminal domain of classical swine fever virus NS4B determines viral genome replication and virulence.

Classical swine fever virus (CSFV) causes a highly contagious disease in pigs that can range from a severe haemorrhagic fever to a nearly unapparent disease, depending on the virulence of the virus strain. Little is known about the viral molecular determinants of CSFV virulence. The nonstructural protein NS4B is essential for viral replication.

Genetic stability of Schmallenberg virus in vivo during an epidemic, and in vitro, when passaged in the highly susceptible porcine SK-6 cell line.

Schmallenberg virus (SBV), an arthropod-borne orthobunyavirus was first detected in 2011 in cattle suffering from diarrhea and fever. The most severe impact of an SBV infection is the induction of malformations in newborns and abortions. Between 2011 and 2013 SBV spread throughout Europe in an unprecedented epidemic wave.

Vesicular stomatitis virus replicon expressing the VP2 outer capsid protein of bluetongue virus serotype 8 induces complete protection of sheep against challenge infection.

Bluetongue virus (BTV) is an arthropod-borne pathogen that causes an often fatal, hemorrhagic disease in ruminants. Different BTV serotypes occur throughout many temperate and tropical regions of the world. In 2006, BTV serotype 8 (BTV-8) emerged in Central and Northern Europe for the first time.

Development and validation of a multiplex, real-time RT PCR assay for the simultaneous detection of classical and African swine fever viruses.

A single-step, multiplex, real-time polymerase chain reaction (RT-PCR) was developed for the simultaneous and differential laboratory diagnosis of Classical swine fever virus (CSFV) and African swine fever virus (ASFV) alongside an exogenous internal control RNA (IC-RNA). Combining a single extraction methodology and primer and probe sets for detection of the three target nucleic acids CSFV, ASFV and IC-RNA, had no effect on the analytical sensitivity of the assay and the new triplex RT-PCR was comparable to standard PCR techniques for CSFV and ASFV diagnosis. After optimisation the assay had a detection limit of 5 CSFV genome copies and 22 ASFV genome copies.

Long-term infection of goats with bluetongue virus serotype 25.

Toggenburg Orbivirus (TOV) is the prototype of bluetongue virus serotype 25 (BTV-25). It was first detected in goats in Switzerland in 2008. The virus does not induce clinical signs in infected goats.

Two newly developed E(rns)-based ELISAs allow the differentiation of Classical Swine Fever virus-infected from marker-vaccinated animals and the discrimination of pestivirus antibodies.

New generations of Classical Swine Fever virus (CSFV) marker vaccines have recently been developed in order to make emergency vaccination in case of a CSF outbreak more feasible. However, the application of a marker vaccine is dependent on the availability of an accompanying discriminatory test allowing differentiation of infected from vaccinated animals (DIVA). CP7_E2alf, the most promising live marker vaccine candidate currently available, is a genetically modified Bovine Viral Diarrhea virus expressing the E2 glycoprotein of CSFV strain Alfort/187.

New insights into the antigenic structure of the glycoprotein E(rns) of classical swine fever virus by epitope mapping.

The E(rns) glycoprotein of classical swine fever virus (CSFV) has been studied in detail concerning biochemical and functional properties, whereas less is known about its antigenic structure. In order to define epitopes recognized by CSFV-specific antibodies, the binding sites of seven E(rns)-specific monoclonal antibodies were investigated. Mapping experiments using chimeric E(rns) proteins, site-directed mutagenesis and an overlapping peptide library identified one antigenic region located between amino acids (aa) 55 to 110 on the E(rns) protein of CSFV Alfort/187.

In vivo and in vitro propagation and transmission of Toggenburg orbivirus.

The Toggenburg orbivirus (TOV), a recently discovered virus related to bluetongue virus (BTV), has been identified in goats in Switzerland, Italy and Germany. Isolation of TOV in vitro has not yet been achieved and the transmission mechanisms are still unknown. In the experimental infection of pregnant goats described here, TOV could not be detected in secretion/excretion samples or fetal blood.

Epidemiology of avian influenza virus in wild birds in Switzerland between 2006 and 2009.

After the spread of H5N1 highly pathogenic avian influenza virus (AIV) from Asia into Russia, the Middle East, Europe, and Africa in 2005-06, the Swiss national AIV surveillance program was extended. One of the new focal points was Lake Constance, where sentinel duck stations and swim-in traps were established within the project Constanze in collaboration with Germany and Austria. More than 2000 samples from 41 species were collected in Switzerland between September 2006 and December 2008.

Detection of Toggenburg Orbivirus by a segment 2-specific quantitative RT-PCR.

Toggenburg Orbivirus (TOV) has been detected recently in healthy goats in Switzerland. The virus is related closely to bluetongue virus (BTV) and is considered tentatively as a 25th serotype of BTV. Upon detection of additional TOV-positive goats in Switzerland, Germany, and Italy, these TOV isolates were characterized genetically by partial sequencing of the viral genome segment 2 which encodes VP2, the major outer capsid protein of orbiviruses.

Virological and pathological findings in Bluetongue virus serotype 8 infected sheep.

Twenty-seven sheep of the four most common Swiss breeds and the English breed Poll Dorset were experimentally infected with a northern European field strain of bluetongue virus serotype 8 (BTV-8). Animals of all breeds developed clinical signs, viremia and pathological lesions, demonstrating that BTV-8 is fully capable of replicating and inducing bluetongue disease (BT) in the investigated sheep. Necropsy performed between 10 and 16 days post-infectionem (d.

Antigenic characterization of recombinant hemagglutinin proteins derived from different avian influenza virus subtypes.

Since the advent of highly pathogenic variants of avian influenza virus (HPAIV), the main focus of avian influenza research has been the characterization and detection of HPAIV hemagglutinin (HA) from H5 and H7 subtypes. However, due to the high mutation and reassortation rate of influenza viruses, in theory any influenza strain may acquire increased pathogenicity irrespective of its subtype. A comprehensive antigenic characterization of influenza viruses encompassing all 16 HA and 9 neuraminidase subtypes will provide information useful for the design of differential diagnostic tools, and possibly, vaccines.

Genetic characterization of toggenburg orbivirus, a new bluetongue virus, from goats, Switzerland.

A novel bluetongue virus (BTV) termed Toggenburg orbivirus (TOV) was detected in goats from Switzerland by using real-time reverse transcription-PCR. cDNA corresponding to the complete sequence of 7 of 10 double-stranded RNA segments of the viral genome was amplified by PCR and cloned into a plasmid vector. Five clones for each genome segment were sequenced to determine a consensus sequence.

Classical swine fever virus can remain virulent after specific elimination of the interferon regulatory factor 3-degrading function of Npro.

Pestiviruses prevent alpha/beta interferon (IFN-alpha/beta) production by promoting proteasomal degradation of interferon regulatory factor 3 (IRF3) by means of the viral N(pro) nonstructural protein. N(pro) is also an autoprotease, and its amino-terminal coding sequence is involved in translation initiation. We previously showed with classical swine fever virus (CSFV) that deletion of the entire N(pro) gene resulted in attenuation in pigs.

Continuous monitoring of bovine spongiform encephalopathy rapid test performance by weak positive tissue controls and quality control charts.

Bovine spongiform encephalopathy (BSE) rapid tests and routine BSE-testing laboratories underlie strict regulations for approval. Due to the lack of BSE-positive control samples, however, full assay validation at the level of individual test runs and continuous monitoring of test performance on-site is difficult. Most rapid tests use synthetic prion protein peptides, but it is not known to which extend they reflect the assay performance on field samples, and whether they are sufficient to indicate on-site assay quality problems.

Phylogenetic characterization of H5N1 highly pathogenic avian influenza viruses isolated in Switzerland in 2006.

In the winter 2005/2006 H5N1 highly pathogenic avian influenza virus (HPAIV) reached Western Europe and caused numerous deaths primarily in migratory water birds. Between February and April 2006 34 cases of H5N1 HPAIV-infected dead water fowl were identified in Switzerland, almost exclusively occurring in the Lake Constance area, a large overwintering area for migratory birds in the eastern part of the country. In total, 13 of these virus isolates were genetically characterized in the present study by full-length nucleotide sequence analysis of the hemagglutinin and neuraminidase-coding region.

Chimeric pestiviruses: candidates for live-attenuated classical swine fever marker vaccines.

The use of attenuated classical swine fever virus (CSFV) strains as live vaccines is no longer allowed for the control of classical swine fever in Europe, due to the inability to differentiate between infected and vaccinated animals (Differentiating Infected from Vaccinated Animals; DIVA), except as emergency vaccines or as bait vaccines for wild boars. Thus, the establishment of a DIVA vaccine(s) is of pivotal importance for the control of this infectious disease. In this study, recombinant versions of the live-attenuated vaccine strain CSFV Riems were generated by replacing parts of the E2 gene with the corresponding sequence of border disease virus strain Gifhorn.

Nonstructural proteins NS2-3 and NS4A of classical swine fever virus: essential features for infectious particle formation.

The nonstructural protein NS2-3 of pestiviruses undergoes tightly regulated processing. For bovine viral diarrhea virus it was shown that uncleaved NS2-3 is required for infectious particle formation while cleaved NS3 is essential for genome replication. To further investigate the functions of NS2-3 and NS4A in the pestivirus life cycle, we established T7 RNA polymerase-dependent trans-complementation for p7-NS2-3-4A of classical swine fever virus (CSFV).

Classical swine fever virus Npro interacts with interferon regulatory factor 3 and induces its proteasomal degradation.

Viruses have evolved a multitude of strategies to subvert the innate immune system by interfering with components of the alpha/beta interferon (IFN-alpha/beta) induction and signaling pathway. It is well established that the pestiviruses prevent IFN-alpha/beta induction in their primary target cells, such as epitheloidal and endothelial cells, macrophages, and conventional dendritic cells, a phenotype mediated by the viral protein N(pro). Central players in the IFN-alpha/beta induction cascade are interferon regulatory factor 3 (IRF3) and IRF7.

Classical swine fever virus replicon particles lacking the Erns gene: a potential marker vaccine for intradermal application.

Classical swine fever virus replicon particles (CSF-VRP) deficient for E(rns) were evaluated as a non-transmissible marker vaccine. A cDNA clone of CSFV strain Alfort/187 was used to obtain a replication-competent mutant genome (replicon) lacking the sequence encoding the 227 amino acids of the glycoprotein E(rns) (A187delE(rns)). For packaging of A187delE(rns) into virus particles, porcine kidney cell lines constitutively expressing E(rns) of CSFV were established.

N(pro) of classical swine fever virus is an antagonist of double-stranded RNA-mediated apoptosis and IFN-alpha/beta induction.

Classical swine fever virus (CSFV) protects cells from double-stranded (ds) RNA-mediated apoptosis and IFN-alpha/beta induction. This phenotype is lost when CSFV lacks N(pro) (DeltaN(pro) CSFV). In the present study, we demonstrate that N(pro) counteracts dsRNA-mediated apoptosis and IFN-alpha/beta induction independently of other CSFV elements.

Oronasal vaccination with classical swine fever virus (CSFV) replicon particles with either partial or complete deletion of the E2 gene induces partial protection against lethal challenge with highly virulent CSFV.

A cDNA clone of the classical swine fever virus (CSFV) strain Alfort/187 [Ruggli N, Tratschin JD, Mittelholzer C, Hofmann MA. Nucleotide sequence of classical swine fever virus strain Alfort/187 and transcription of infectious RNA from stably cloned full-length cDNA. J Virol 1996;70(6):3478-87] was used to construct two E2 deletion mutants lacking either the complete E2 gene or, alternatively, a stretch of 204 nucleotides encoding 68 amino acids located in the C-terminal region of the E2 glycoprotein.

Attenuation of classical swine fever virus by deletion of the viral N(pro) gene.

We have reported earlier that replacement of the N(pro) gene of classical swine fever virus (CSFV) by the murine ubiquitin gene only slightly affects the characteristics of virus replication in the porcine kidney cell line SK-6 [J. Virol. 72 (1998) 7681].