References of "Muylkens, Benoît"
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See detailBovine herpesvirus 1 infection and infectious bovine rhinotracheitis
Muylkens, Benoît ULg; Thiry, Julien ULg; Kirten, P. et al

in Veterinary Research (2007), 38(2), 181-209

Bovine herpesvirus 1 (BoHV-1), classified as an alphaherpesvirus, is a major pathogen of cattle. Primary infection is accompanied by various clinical manifestations such as infectious bovine ... [more ▼]

Bovine herpesvirus 1 (BoHV-1), classified as an alphaherpesvirus, is a major pathogen of cattle. Primary infection is accompanied by various clinical manifestations such as infectious bovine rhinotracheitis, abortion, infectious pustular vulvovaginitis, and systemic infection in neonates. When animals survive, a life-long latent infection is established in nervous sensory ganglia. Several reactivation stimuli can lead to viral re-excretion, which is responsible for the maintenance of BoHV-1 within a cattle herd. This paper focuses on an updated pathogenesis based on a molecular characterization of BoHV-1 and the description of the virus cycle. Special emphasis is accorded to the impact of the latency and reactivation cycle on the epidemiology and the control of BoHV-1. Several European countries have initiated BoHV-1 eradication schemes because of the significant losses incurred by disease and trading restrictions. The vaccines used against BoHV-1 are described in this context where the differentiation of infected from vaccinated animals is of critical importance to achieve BoHV-1 eradication. [less ▲]

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See detailIntraspecific bovine herpesvirus 1 recombinants carrying glycoprotein E deletion as a vaccine marker are virulent in cattle
Muylkens, Benoît ULg; Meurens, F.; Schynts, F. et al

in Journal of General Virology (2006), 87(Pt 8), 2149-2154

Vaccines used in control programmes of Bovine herpesvirus 1 (BoHV-1) utilize highly attenuated BoHV-1 strains marked by a deletion of the glycoprotein E (gE) gene. Since BoHV-1 recombinants are obtained ... [more ▼]

Vaccines used in control programmes of Bovine herpesvirus 1 (BoHV-1) utilize highly attenuated BoHV-1 strains marked by a deletion of the glycoprotein E (gE) gene. Since BoHV-1 recombinants are obtained at high frequency in experimentally coinfected cattle, the consequences of recombination on the virulence of gE-negative BoHV-1 were investigated. Thus, gE-negative BoHV-1 recombinants were generated in vitro from several virulent BoHV-1 and one mutant BoHV-1 deleted in the gC and gE genes. Four gE-negative recombinants were tested in the natural host. All the recombinants were more virulent than the gE-negative BoHV-1 vaccine and the gC- and gE-negative parental BoHV-1. The gE-negative recombinant isolated from a BoHV-1 field strain induced the highest severe clinical score. Latency and reactivation studies showed that three of the recombinants were reexcreted. Recombination can therefore restore virulence of gE-negative BoHV-1 by introducing the gE deletion into a different virulence background. [less ▲]

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See detailRecombination in the alphaherpesvirus bovine herpesvirus 1
Thiry, Etienne ULg; Muylkens, Benoît ULg; Meurens, F. et al

in Veterinary Microbiology (2006), 113(3-4), 171-177

Herpesviruses are DNA viruses characterized by a low rate of nucleotide substitution. Therefore. other mechanisms must be involved to their evolution, like recombination that can be seen as an essential ... [more ▼]

Herpesviruses are DNA viruses characterized by a low rate of nucleotide substitution. Therefore. other mechanisms must be involved to their evolution, like recombination that can be seen as an essential evolutionary driving force of these viruses. Recombination contributes to the long-term evolution of alphaherpes viruses. It acts also to continuously create new alphaherpesvirus strains. We have used bovine herpesvirus 1 to investigate recombination both within DNA concatemers in infected cells and in vitro and in vivo at the end of the lytic cycle. The following results have been obtained: (i) intramolecular recombination occurs at the level of concatemers and gives rise to genomic segment inversions: (ii) intraspecific recombination occurs frequently both in vitro and in vivo; (iii) interspecific recombination is possible and requires two highly genetically related viruses (iv) only simultaneous or closely separated infections lead to the production of recombinant viruses: (v) recombination between wild-type and glycoprotein defective vaccine virus can produce a glycoprotein defective virus keeping part of the virulence of parental wild-type virus. Recombination, by exchanging genomic segments, may modify the virulence of alphaherpesviruses. It must be carefully assessed for the biosafety of antiviral therapy, alphaherpesvirus-based vectors and live attenuated vaccines. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]

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See detailBiological characterization of bovine herpesvirus 1 recombinants possessing the vaccine glycoprotein E negative phenotype
Muylkens, Benoît ULg; Meurens, F.; Schynts, F. et al

in Veterinary Microbiology (2006), 113(3-4), 283-291

Intramolecular recombination is a frequent event during the replication cycle of bovine herpesvirus 1 (BoHV-1). Recombinant viruses frequently arise and survive in cattle after concomitant nasal ... [more ▼]

Intramolecular recombination is a frequent event during the replication cycle of bovine herpesvirus 1 (BoHV-1). Recombinant viruses frequently arise and survive in cattle after concomitant nasal infections with two BoHV-1 mutants. The consequences of this process, related to herpesvirus evolution, have to be assessed in the context of large use of live marker vaccines based on glycoprotein E (gE) gene deletion. In natural conditions, double nasal infections by vaccine and wild-type strains are likely to occur. This situation might generate virulent recombinant viruses inducing a serological response indistinguishable from the vaccine one. This question was addressed by generating in vitro BoHV-1 recombinants deleted in the gE gene from seven wild-type BoHV-1 strains and one mutant strain deleted in the genes encoding gC and gE. In vitro growth properties were assessed by virus production, one step growth kinetics and plaque size assay. Heterogeneity in the biological properties was shown among the investigated recombinant viruses. The results demonstrated that some recombinants. in spite of their gE minus phenotype, have biological characteristics close to wild-type BoHV-1. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]

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See detailEstimation du coût global d'un plan de lutte contre l'IBR en Belgique
Dispas, Marc; Houtain, Jean Yves; Muylkens, Benoît ULg et al

in Epidémiologie et Santé Animale (2006), 49

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See detailRuminant alphaherpesviruses related to bovine herpesvirus 1.
Thiry, Julien ULg; Keuser, Veronique; Muylkens, Benoît ULg et al

in Veterinary Research (2006), 37(2), 169-90

Herpesviruses have mainly co-evolved with their hosts for millions of years. Consequently, different related host species may have been infected by various genetically related herpesviruses. Illustrating ... [more ▼]

Herpesviruses have mainly co-evolved with their hosts for millions of years. Consequently, different related host species may have been infected by various genetically related herpesviruses. Illustrating this concept, several ruminant alphaherpesviruses have been shown to form a cluster of viruses closely related to bovine herpesvirus 1 (BoHV-1): namely bovine herpesvirus 5, bubaline herpesvirus 1, caprine herpesvirus 1, cervid herpesviruses 1 and 2 and elk herpesvirus 1. These viruses share common antigenic properties and the serological relationships between them can be considered as a threat to BoHV-1 eradication programmes. BoHV-1 is a herpesvirus responsible for infectious bovine rhinotracheitis, which is a disease of major economic concern. In this article, the genetic properties of these ruminant alphaherpesviruses are reviewed on a comparative basis and the issue of interspecific recombination is assessed. The pathogenesis of these infections is described with emphasis on the host range and crossing of the host species barrier. Indeed, the non bovine ruminant species susceptible to these ruminant alphaherpesviruses may be potential BoHV-1 reservoirs. The differential diagnosis of these related infections is also discussed. In addition, available epidemiological data are used to assess the potential of cross-infection in ruminant populations. A better knowledge of these ruminant alphaherpesvirus infections is essential to successfully control infectious bovine rhinotracheitis. [less ▲]

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See detailRecombination in alphaherpesviruses
Thiry, Etienne ULg; Meurens, F.; Muylkens, Benoît ULg et al

in Reviews in Medical Virology (2005), 15(2, Mar-Apr), 89-103

Within the Herpesviridae family, Alphaherpesvirinae is an extensive subfamily which contains numerous mammalian and avian viruses. Given the low rate of herpesvirus nucleotide substitution, recombination ... [more ▼]

Within the Herpesviridae family, Alphaherpesvirinae is an extensive subfamily which contains numerous mammalian and avian viruses. Given the low rate of herpesvirus nucleotide substitution, recombination can be seen as an essential evolutionary driving force although it is likely underestimated. Recombination in alphaherpesviruses is intimately linked to DNA replication. Both viral and cellular proteins participate in this recombination-dependent replication. The presence of inverted repeats in the alphaherpesvirus genomes allows segment inversion as a consequence of specific recombination between repeated sequences during DNA replication. High molecular weight intermediates of replication, called concatemers, are the site of early recombination events. The analysis of concatemers, from cells coinfected by two distinguishable alphaherpesviruses provides an efficient tool to study recombination without the bias introduced by invisible or non-viable recombinants, and by dominance of a virus over recombinants. Intraspecific recombination frequently occurs between strains of the same alphaherpesvirus species. Interspecific recombination depends on enough sequence similarity to enable recombination between distinct alphaherpesvirus species. The most important prerequisite for successful recombination is coinfection of the individual host by different virus strains or species. Consequently the following factors affecting the distribution of different viruses to shared target cells need to be considered: dose of inoculated virus, time interval between inoculation of the first and the second virus, distance between the marker mutations, genetic homology, virulence and latency. Recombination, by exchanging genomic segments, may modify the virulence of alphaherpesviruses. It must be carefully assessed for the biosafety of antiviral therapy, alphaherpesvirus-based vectors and live attenuated vaccines. Copyright (C) 2004 John Wiley Sons, Ltd. [less ▲]

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See detailInterspecific recombination between two ruminant alphaherpesviruses, bovine herpesviruses 1 and 5
Meurens, F.; Keil, G. M.; Muylkens, Benoît ULg et al

in Journal of Virology (2004), 78(18), 9828-9836

Homologous recombination between different species of alphaherpesviruses has been described between herpes simplex viruses 1 and 2 but has not yet been observed between other alphaherpesviruses. In the ... [more ▼]

Homologous recombination between different species of alphaherpesviruses has been described between herpes simplex viruses 1 and 2 but has not yet been observed between other alphaherpesviruses. In the present study we chose to assess to what extent in vitro recombination can occur between members of a well-defined group of closely related viruses such as ruminant alphaherpesviruses. At 24 h after infection of epithelial bovine kidney cells with a double-deleted mutant of bovine herpesvirus 1 (BoHV-1) (containing green fluorescent protein and red fluorescent protein genes) and different ruminant alphaherpesviruses, four types of progeny viruses were detected and distinguished according to their phenotype. Frequent recombination events between identical or different strains of BoHV-1 were observed (up to 30%), whereas only two BoHV-1/BoHV-5 recombinants were identified, and no recombinants between BoHV-1 and less closely related caprine and cervine herpesviruses were detected. Restriction analysis of the genomes of the two BoHV-1/BoHV-5 recombinants showed different genetic backgrounds. One possessed a restriction pattern close to BoHV-1, whereas the other one was close to BoHV-5. This exhaustive analysis of each combination of coinfection in a unique situation of five closely related alphaherpesviruses revealed the importance of a high degree of genetic relatedness and similar parental virus growth kinetics for successful interspecific recombination. [less ▲]

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See detailSuperinfection prevents recombination of the alphaherpesvirus bovine herpesvirus 1
Meurens, F.; Schynts, F.; Keil, G. M. et al

in Journal of Virology (2004), 78(8), 3872-3879

Homologous recombination between strains of the same alphaherpesvirus species occurs frequently both in vitro and in vivo. This process has been described between strains of herpes simplex virus type 1 ... [more ▼]

Homologous recombination between strains of the same alphaherpesvirus species occurs frequently both in vitro and in vivo. This process has been described between strains of herpes simplex virus type 1, herpes simplex virus type 2, pseudorabies virus, feline herpesvirus 1, varicella-zoster virus, and bovine herpesvirus 1 (BoHV-1). In vivo, the rise of recombinant viruses can be modulated by different factors, such as the dose of the inoculated viruses, the distance between inoculation sites, the time interval between inoculation of the first and the second virus, and the genes in which the mutations are located. The effect of the time interval between infections with two distinguishable BoHV-1 on recombination was studied in three ways: (i) recombination at the level of progeny viruses, (ii) interference induced by the first virus infection on beta-gallactosidase gene expression of a superinfecting virus, and (iii) recombination at the level of concatemeric DNA. A time interval of 2 to 8 h between two successive infections allows the establishment of a barrier, which reduces or prevents any successful superinfection needed to generate recombinant viruses. The dramatic effect of the time interval on the rise of recombinant viruses is particularly important for the risk assessment of recombination between glycoprotein E-negative marker vaccine and field strains that could threaten BoHV-1 control and eradication programs. [less ▲]

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See detailDiarrhée virale bovine et maladie des muqueuses : vaccination contre l'infection par le virus de la BVD-MD
Thiry, Etienne ULg; Gogev, Sacha; Meurens, François et al

in Point Vétérinaire (2004), 35

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See detailLes facteurs de virulence des alphaherpèsvirus
Muylkens, Benoît ULg; Meurens, François; Schynts, Frédéric et al

in Virologie (2003), 7

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See detailL'interférence virale chez les Alphaherpesvirinae
Meurens, François; Muylkens, Benoît ULg; Schynts, Frédéric et al

in Virologie (2003), 7

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See detailRéplication, clivage-encapsidation et recombinaison de l'ADN des herpèsvirus
Schynts, Frédéric; Meurens, François; Muylkens, Benoît ULg et al

in Virologie (2002), 6

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