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Background: Whereas temporal gene expression in mammalian herpesviruses has been studied extensively, little is known about gene expression in fish herpesviruses. Here we report a genome-wide transcription analysis of a fish herpesvirus, anguillid herpesvirus 1, in cell culture, studied during the first 6 hours of infection using reverse transcription quantitative PCR. Results: Four immediate-early genes - open reading frames 1, 6A, 127 and 131 - were identified on the basis of expression in the presence of a protein synthesis inhibitor and unique expression profiles during infection in the absence of inhibitor. All of these genes are located within or near the terminal direct repeats. The remaining 122 open reading frames were clustered into groups on the basis of transcription profiles during infection. Expression of these genes was also studied in the presence of a viral DNA polymerase inhibitor, enabling classification into early, early-late and late genes. In general, clustering by expression profile and classification by inhibitor studies corresponded well. Most early genes encode enzymes and proteins involved in DNA replication, most late genes encode structural proteins, and early-late genes encode non-structural as well as structural proteins. Conclusions: Overall, anguillid herpesvirus 1 gene expression was shown to be regulated in a temporal fashion, comparable to that of mammalian herpesviruses. [ABSTRACT FROM AUTHOR]

The emergence of SARS-CoV-2 in December 2019 resulted in the COVID-19 pandemic. Recurring disease outbreaks repeatedly overloaded the public health sector and severely affected the global economy. We developed a candidate COVID-19 vaccine based on a recombinant Newcastle disease virus (NDV) vaccine vector, encoding a pre-fusion stabilized full-length Spike protein obtained from the original SARS-CoV-2 Wuhan isolate. Vaccination of hamsters by intra-muscular injection or intra-nasal instillation induced high neutralizing antibody responses. Intranasal challenge infection with SARS-CoV-2 strain Lelystad demonstrated that both vaccination routes provided partial protection in the upper respiratory tract, and almost complete protection in the lower respiratory tract, as measured by suppressed viral loads and absence of histological lung lesions. Activity wheel measurements demonstrated that animals vaccinated by intranasal inoculation rapidly recovered to normal activity. NDV constructs encoding the spike of SARS-CoV-2 may be attractive candidates for development of intra-nasal COVID-19 booster vaccines., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Laboratory response networks (LRNs) have been established for security reasons in several countries including the Netherlands, France, and Sweden. LRNs function in these countries as a preparedness measure for a coordinated diagnostic response capability in case of a bioterrorism incident or other biocrimes. Generally, these LRNs are organized on a national level. The EU project AniBioThreat has identified the need for an integrated European LRN to strengthen preparedness against animal bioterrorism. One task of the AniBioThreat project is to suggest a plan to implement laboratory biorisk management CWA 15793:2011 (CWA 15793), a management system built on the principle of continual improvement through the Plan-Do-Check-Act (PDCA) cycle. The implementation of CWA 15793 can facilitate trust and credibility in a future European LRN and is an assurance that the work done at the laboratories is performed in a structured way with continuous improvements. As a first step, a gap analysis was performed to establish the current compliance status of biosafety and laboratory biosecurity management with CWA 15793 in 5 AniBioThreat partner institutes in France (ANSES), the Netherlands (CVI and RIVM), and Sweden (SMI and SVA). All 5 partners are national and/or international laboratory reference institutes in the field of public or animal health and possess high-containment laboratories and animal facilities. The gap analysis showed that the participating institutes already have robust biorisk management programs in place, but several gaps were identified that need to be addressed. Despite differences between the participating institutes in their compliance status, these variations are not significant. Biorisk management exercises also have been identified as a useful tool to control compliance status and thereby implementation of CWA 15793. An exercise concerning an insider threat and loss of a biological agent was performed at SVA in the AniBioThreat project to evaluate implementation of the contingency plans and as an activity in the implementation process of CWA 15793. The outcome of the exercise was perceived as very useful, and improvements to enhance biorisk preparedness were identified. Gap analyses and exercises are important, useful activities to facilitate implementation of CWA 15793. The PDCA cycle will enforce a structured way to work, with continual improvements concerning biorisk management activities. Based on the activities in the AniBioThreat project, the following requirements are suggested to promote implementation: support from the top management of the organizations, knowledge about CWA 15793, a compliance audit checklist and gap analysis, training and exercises, networking in LRNs and other networks, and interinstitutional audits. Implementation of CWA 15793 at each institute would strengthen the European animal bioterrorism response capabilities by establishing a well-prepared LRN.

Newcastle disease (ND) is one of the most important diseases of poultry, and may cause devastating losses in the poultry industry worldwide. Its causative agent is Newcastle disease virus (NDV), also known as avian paramyxovirus type 1. Many countries maintain a stringent vaccination policy against ND, but there are indications that ND outbreaks can still occur despite intensive vaccination. It has been argued that this may be due to antigenic divergence between the vaccine strains and circulating field strains. Here we present the complete genome sequence of a highly virulent genotype VII virus (NL/93) obtained from vaccinated poultry during an outbreak of ND in the Netherlands in 1992-1993. Using this strain, we investigated whether the identified genetic evolution of NDV is accompanied by antigenic evolution. In this study we show that a live vaccine that is antigenically adapted to match the genotype VII NL/93 outbreak strain does not provide increased protection compared to a classic genotype II live vaccine. When challenged with the NL/93 strain, chickens vaccinated with a classic vaccine were completely protected against clinical disease and mortality and virus shedding was significantly reduced, even with a supposedly suboptimal vaccine dose. These results suggest that it is not antigenic variation but rather poor flock immunity due to inadequate vaccination practices that may be responsible for outbreaks and spreading of virulent NDV field strains., (Copyright © 2012 Elsevier B.V. All rights reserved.)

In the last decade many studies have been performed on the virulence of Newcastle disease virus (NDV). This is mainly due to the development of reverse genetics systems which made it possible to genetically modify NDV and to investigate the contribution of individual genes and genome regions to its virulence. However, the available information is scattered and a comprehensive overview of the factors and conditions determining NDV virulence is lacking. This review summarises, compares and discusses the available literature and shows that virulence of NDV is a complex trait determined by multiple genetic factors.

Many of the known fish herpesviruses have important aquaculture species as their natural host, and may cause serious disease and mortality. Anguillid herpesvirus 1 (AngHV-1) causes a hemorrhagic disease in European eel, Anguilla anguilla. Despite their importance, fundamental molecular knowledge on fish herpesviruses is still limited. In this study we describe the identification and localization of the structural proteins of AngHV-1. Purified virions were fractionated into a capsid-tegument and an envelope fraction, and premature capsids were isolated from infected cells. Proteins were extracted by different methods and identified by mass spectrometry. A total of 40 structural proteins were identified, of which 7 could be assigned to the capsid, 11 to the envelope, and 22 to the tegument. The identification and localization of these proteins allowed functional predictions. Our findings include the identification of the putative capsid triplex protein 1, the predominant tegument protein, and the major antigenic envelope proteins. Eighteen of the 40 AngHV-1 structural proteins had sequence homologues in related Cyprinid herpesvirus 3 (CyHV-3). Conservation of fish herpesvirus structural genes seemed to be high for the capsid proteins, limited for the tegument proteins, and low for the envelope proteins. The identification and localization of the structural proteins of AngHV-1 in this study adds to the fundamental knowledge of members of the Alloherpesviridae family, especially of the Cyprinivirus genus.

Two pathogenetically different pigeon paramyxovirus type 1 (PPMV-1) virus clones were recently derived by passage of a single isolate with an intracerebral pathogenicity index (ICPI) of 0.32. The virus clones had an ICPI of 0.025 and 1.3, respectively (Fuller et al., 2007). Remarkably both viruses contained a cleavage site motif in the precursor fusion (F) protein that is usually associated with virulent viruses. In the current study, both viral genomes were completely sequenced and only four amino acid differences were observed. Of these, two were considered irrelevant on theoretical grounds and two amino acid changes were unique for virus 0.025. The latter were introduced into an infectious clone of a virulent Newcastle disease virus strain, individually and combined, and the effects of the mutations on pathogenicity were examined. The results indicate that only the S453P substitution in the F protein had a modest effect on pathogenicity. We were not able to identify the molecular basis for the pathogenicity difference between both viruses. However, our observations emphasize the need to determine both the virulence (ICPI) and the sequence of the cleavage site of the F protein to avoid dismissing of potential virulent PPMV-1 isolates., ((c) 2009 Elsevier B.V. All rights reserved.)

Eel herpesvirus or anguillid herpesvirus 1 (AngHV1) frequently causes disease in freshwater eels. The complete genome sequence of AngHV1 and its taxonomic position within the family Alloherpesviridae were determined. Shotgun sequencing revealed a 249 kbp genome including an 11 kbp terminal direct repeat that contains 7 of the 136 predicted protein-coding open reading frames. Twelve of these genes are conserved among other members of the family Alloherpesviridae and another 28 genes have clear homologues in cyprinid herpesvirus 3. Phylogenetic analyses based on amino acid sequences of five conserved genes, including the ATPase subunit of the terminase, confirm the position of AngHV1 within the family Alloherpesviridae, where it is most closely related to the cyprinid herpesviruses. Our analyses support a recent proposal to subdivide the family Alloherpesviridae into two sister clades, one containing AngHV1 and the cyprinid herpesviruses and the other containing Ictalurid herpesvirus 1 and the ranid herpesviruses.

Infectious bursal disease virus (IBDV), a nonenveloped double-stranded RNA virus of chicken, encodes five proteins. Of these, the RNA-dependent RNA polymerase (VP1) is specified by the smaller genome segment, while the large segment directs synthesis of a nonstructural protein (VP5) and a structural protein precursor from which the capsid proteins pVP2 and VP3 as well as the viral protease VP4 are derived. Using the recently redefined processing sites of the precursor, we have reevaluated the homotypic interactions of the viral proteins using the yeast two-hybrid system. Except for VP1, which interacted weakly, all proteins appeared to self-associate strongly. Using a deletion mutagenesis approach, we subsequently mapped the interacting domains in these polypeptides, where possible confirming the observations made in the two-hybrid system by performing coimmunoprecipitation analyses of tagged protein constructs coexpressed in avian culture cells. The results revealed that pVP2 possesses multiple interaction domains, consistent with available structural information about this external capsid protein. VP3-VP3 interactions were mapped to the amino-terminal part of the polypeptide. Interestingly, this domain is distinct from two other interaction domains occurring in this internal capsid protein: while binding to VP1 has been mapped to the carboxy-terminal end of the protein, interaction with the genomic dsRNA segments has been suggested to occur just upstream thereof. No interaction sites could be assigned to the VP4 protein; any deletion applied abolished its self-association. Finally, one interaction domain was detected in the central, most hydrophobic region of VP5, supporting the idea that this virulence determinant may function as a membrane pore-forming protein in infected cells.