References of "Schynts, Frédéric"
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See detailVariation of inflammatory dynamics and mediators in primiparous cows after intramammary challenge with Escherichia coli.
Pezeshki, Adel; Stordeur, Philippe; Wallemacq, Hugues et al

in Veterinary Research (2011), 42(1), 15

ABSTRACT: The objective of the current study was to investigate (i) the outcome of experimentally induced Escherichia coli mastitis in primiparous cows during early lactation in relation with production ... [more ▼]

ABSTRACT: The objective of the current study was to investigate (i) the outcome of experimentally induced Escherichia coli mastitis in primiparous cows during early lactation in relation with production of eicosanoids and inflammatory indicators, and (ii) the validity of thermography to evaluate temperature changes on udder skin surface after experimentally induced E. coli mastitis. Nine primiparous Holstein Friesian cows were inoculated 24 +/- 6 days (d) after parturition in both left quarters with E. coli P4 serotype O32:H37. Blood and milk samples were collected before and after challenge with E. coli. The infrared images were taken from the caudal view of the udder following challenge with E. coli. No relationship was detected between severity of mastitis and changes of thromboxane B2 (TXB2), leukotriene B4 (LTB4) and lipoxin A4 (LXA4). However, prostaglandin E2 (PGE2) was related to systemic disease severity during E. coli mastitis. Moreover, reduced somatic cell count (SCC), fewer circulating basophils, increased concentration of tumor necrosis factor-alpha (TNF-alpha) and higher milk sodium and lower milk potassium concentrations were related to systemic disease severity. The thermal camera was capable of detecting 2-3 degrees C temperature changes on udder skin surface of cows inoculated with E. coli. Peak of udder skin temperature occurred after peak of rectal temperature and appearance of local signs of induced E. coli mastitis. Although infrared thermography was a successful method for detecting the changes in udder skin surface temperature following intramammary challenge with E. coli, it did not show to be a promising tool for early detection of mastitis. [less ▲]

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See detailCo-infection with two closely related alphaherpesviruses results in a highly diversified recombination mosaic displaying negative genetic interference
Muylkens, Benoît ULg; Farnir, Frédéric ULg; Meurens, François et al

in Journal of Virology (2009), 83(7), 3127-3137

Phylogenetic studies of the emergence and spread of natural recombinants in herpesviruses infecting humans and animals have been reported recently. However, despite an ever-increasing amount of evidence ... [more ▼]

Phylogenetic studies of the emergence and spread of natural recombinants in herpesviruses infecting humans and animals have been reported recently. However, despite an ever-increasing amount of evidence of recombination in herpesvirus history, the recombination process and the consequences on the genetic diversity of the progeny remain poorly characterized. We addressed this issue by using multiple single-nucleotide polymorphisms (SNPs) differentiating the two subtypes of an alphaherpesvirus, bovine herpesvirus 1 (BoHV-1). Analysis of a large sample of progeny virions obtained in a single growth cycle of coinfected BoHV-1 strains provided a prospective investigation of the recombination dynamics by using SNPs as recombination markers. We found that the simultaneous infection with two closely related herpesviruses results in a highly diversified recombination mosaic. From the analysis of multiple recombinants arising in the progeny, we provide the first evidence of genetic interference influencing the recombination process in herpesviruses. In addition, we report striking differences in the levels of recombination frequency observed along the BoHV-1 genome. With particular emphasis on the genetic structure of a progeny virus population rising in vitro, our data show to which extent recombination participates to the genetic diversification of herpesviruses [less ▲]

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See detailCharacterization of the cattle serum antibody responses against TEM beta-lactamase and the nonimmunogenic Escherichia coli heat-stable enterotoxin (STaI)
Zervosen, Astrid ULg; Saegerman, Claude ULg; Antoniotti, Ingrid et al

in FEMS Immunology & Medical Microbiology (2008), 54(3), 319-329

In order to test the use of a subunit recombinant vaccine for its capacity to induce antibodies against the nonimmunogenic heat-stable enterotoxin STa from Escherichia coli and the TEM-1 beta-lactamase ... [more ▼]

In order to test the use of a subunit recombinant vaccine for its capacity to induce antibodies against the nonimmunogenic heat-stable enterotoxin STa from Escherichia coli and the TEM-1 beta-lactamase, cattle were immunized with a hybrid protein created by insertion of the STa sequence at position 197 of the TEM-1 beta-lactamase. Specific anti-STa IgG and IgG1 antibodies were detected at low levels, while no IgG2 antibodies were detected. In contrast, high levels of the different anti-TEM IgG subtypes were detected in cattle sera. In addition, beta-lactamase activity was inhibited by the sera. The presence of antibodies against STa and TEM-1 beta-lactamase was assessed in sera from 366 cattle taken from the field. No significant level of IgGs against the toxin or the TEM-1 was detected. A comparison of the antibody level between the immunized and the nonimmunized animals clearly demonstrated that STa was not able to induce a significant level of antibodies in the vaccinated animals. In contrast, a strong antibody response against TEM-1 beta-lactamase was demonstrated. [less ▲]

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See detailLa recombinaison, moteur de diversité chez les alphaherpèsvirus, a de profondes implications médicales
Thiry, Etienne ULg; Meurens, François; Schynts, Frédéric et al

in Bulletin de l'Académie Royale de Médecine de Belgique (2007), 168

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See detailDevelopment of a 1-step enzyme-linked immunosorbent assay for the rapid diagnosis of bovine respiratory syncytial virus in postmortem specimens.
Quinting, Birgit; Robert, Beatrice; Letellier, Carine et al

in Journal of Veterinary Diagnostic Investigation (2007), 19(3), 238-43

Bovine respiratory syncytial virus (BRSV) is associated with severe respiratory disease in cattle. BRSV infection frequently leads to the death of young infected animals. The presence of BRSV in ... [more ▼]

Bovine respiratory syncytial virus (BRSV) is associated with severe respiratory disease in cattle. BRSV infection frequently leads to the death of young infected animals. The presence of BRSV in postmortem specimens is routinely detected using indirect immunofluorescence (IIF). However, this technique requires special equipment and considerable expertise. The present paper describes the development of a 1-step ELISA for rapid (1.5 hours) detection of BRSV antigen in organ homogenates. The performance of the new 1-step ELISA was evaluated using bovine postmortem specimens (n = 108) in comparison with 3 other BRSV diagnostic techniques: indirect immunofluorescence, the Clearview respiratory syncytial virus (RSV) test, and real-time reverse transcriptase polymerase chain reaction (RT-PCR). The relative sensitivity, specificity, and the kappa coefficient of 1-step ELISA, the Clearview RSV electroimmunoassay (EIA), and IIF were calculated, using real-time RT-PCR as the reference test. The new 1-step ELISA was the most sensitive and specific of the 3 tests. Thus, the new 1-step ELISA is a reliable test for detecting BRSV antigen in organ homogenates. [less ▲]

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See detailEvaluation de la séroprévalence de l'infection à herpèsvirus caprin 1 dans le sud-ouest de l'Europe
Thiry, Julien ULg; Keuser, Véronique; Schynts, Frédéric et al

in Epidémiologie et Santé Animale (2006), 49

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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 detailRhinotrachéite infectieuse bovine
Thiry, Etienne ULg; Schynts, Frédéric; Gogev, Sacha et al

in Lefèvre, P. C.; Blancou, Jean; Chermette, R. (Eds.) Principales maladies infectieuses et parasitaires du bétail, Europe et régions chaudes, généralités, maladies virales (2003)

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See detailRecent developments in infectious bovine rhinotracheitis
Thiry, Etienne ULg; Lemaire, Mylène; Keuser, Véronique et al

in Cattle Practice (2002), 10

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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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See detailLatency and Reactivation of a Glycoprotein E Negative Bovine Herpesvirus Type 1 Vaccine: Influence of Virus Load and Effect of Specific Maternal Antibodies
Lemaire, Mylène; Schynts, Frédéric; Meyer, Gilles et al

in Vaccine (2001), 19(32), 4795-804

The effects of the vaccination of neonatal calves with a glycoprotein E (gE)-negative bovine herpesvirus type 1 (BHV-1) were investigated in naive and passively immunised calves either with the ... [more ▼]

The effects of the vaccination of neonatal calves with a glycoprotein E (gE)-negative bovine herpesvirus type 1 (BHV-1) were investigated in naive and passively immunised calves either with the recommended dose or a 5-fold concentrated one. After inoculation (PI), all calves excreted the virus vaccine except three passively immunised calves inoculated with the lower titre. No antibody response could be detected in passively immunised calves, whatever the dose used, and they all became BHV-1 seronegative and remained so after dexamethasone treatment (PDT). Nevertheless, as shown by a gamma-interferon assay, all calves that excreted the vaccine PI developed a cell-mediated immune response and a booster response was observed PDT, suggesting viral reactivation. The vaccine virus was recovered PDT from nasal secretions in two calves and BHV-1 DNA were detected in trigeminal ganglia from five calves belonging to all inoculated groups. The results show that the BHV-1 gE-negative vaccine can establish latency not only in naive but also in passively immunised neonatal calves after a single intranasal inoculation. Moreover, this study shows for the first time that the gE-negative vaccine, when used in passively immunised calves, can lead to seronegative vaccine virus carriers. [less ▲]

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See detailLa recombinaison chez les alphaherpèsvirus
Meurens, François; Schynts, Frédéric; Thiry, Etienne ULg

in Annales de Médecine Vétérinaire (2001), 145

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See detailSpecific Passive Immunity Reduces the Excretion of Glycoprotein E-Negative Bovine Herpesvirus Type 1 Vaccine Strain in Calves
Lemaire, Mylène; Hanon, E.; Schynts, Frédéric et al

in Vaccine (2000), 19(9-10), 1013-7

We investigated the excretion of either a glycoprotein E (gE)-negative bovine herpesvirus type 1 (BHV1) vaccine strain or a conventional modified-live vaccine strain in both naive and passively immunised ... [more ▼]

We investigated the excretion of either a glycoprotein E (gE)-negative bovine herpesvirus type 1 (BHV1) vaccine strain or a conventional modified-live vaccine strain in both naive and passively immunised calves. The replication of gE-negative strain was considerably reduced in the maternally immunised calves, in comparison with the non-immune calves. On the other hand, the excretion of the gE-positive conventional vaccine strain was not reduced and even seemed to be prolonged in the presence of maternal antibodies. These results suggest that BHV1 gE may play a role in virus survival in the presence of antibodies. [less ▲]

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See detailProduction of Bovine Herpesvirus Type 1-Seronegative Latent Carriers by Administration of a Live-Attenuated Vaccine in Passively Immunized Calves
Lemaire, Mylène; Meyer, Gilles; Baranowski, Eric et al

in Journal of Clinical Microbiology (2000), 38(11), 4233-8

The consequences of the vaccination of neonatal calves with the widely used live-attenuated temperature-sensitive (ts) bovine herpesvirus type 1 (BHV-1) were investigated. The ts strain established acute ... [more ▼]

The consequences of the vaccination of neonatal calves with the widely used live-attenuated temperature-sensitive (ts) bovine herpesvirus type 1 (BHV-1) were investigated. The ts strain established acute and latent infections in all vaccinated calves either with or without passive immunity. Four of seven calves vaccinated under passive immunity became clearly BHV-1 seronegative by different serological tests, as did uninfected control calves after the disappearance of maternal antibodies, and they remained so for long periods. A cell-mediated immune response was detected by a BHV-1 gamma interferon assay, but this test failed to detect the seronegative latent carriers (SNLCs). While they are not detected, SNLCs represent a threat for BHV-1-free herds or countries. This study demonstrates that SNLCs can be easily obtained by inoculation with a live-attenuated BHV-1 under passive immunity and that latent carrier animals without any antibody do exist. Consequently, this situation could represent a good model to experimentally produce SNLCs. [less ▲]

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See detailEffects of Bovine Herpesvirus Type 1 Infection in Calves with Maternal Antibodies on Immune Response and Virus Latency
Lemaire, Mylène; Weynants, Vincent; Godfroid, Jacques et al

in Journal of Clinical Microbiology (2000), 38(5), 1885-94

The presence of maternally derived antibodies can interfere with the development of an active antibody response to antigen. Infection of seven passively immunized young calves with a virulent strain of ... [more ▼]

The presence of maternally derived antibodies can interfere with the development of an active antibody response to antigen. Infection of seven passively immunized young calves with a virulent strain of bovine herpesvirus type 1 (BHV-1) was performed to determine whether they could become seronegative after the disappearance of maternal antibodies while latently infected with BHV-1. Four uninfected calves were controls. All calves were monitored serologically for 13 to 18 months. In addition, the development of a cell-mediated immune response was assessed by an in vitro antigen-specific gamma interferon (IFN-gamma) production assay. All calves had positive IFN-gamma responses as early as 7 days until at least 10 weeks after infection. However, no antibody rise was observed after infection in the three calves with the highest titers of maternal antibodies. One of the three became seronegative by virus neutralization test at 7 months of age like the control animals. This calf presented negative IFN-gamma results at the same time and was classified seronegative by enzyme-linked immunosorbent assay at around 10 months of age. This calf was latently infected, as proven by virus reexcretion after dexamethasone treatment at the end of the experiment. In conclusion, this study demonstrated that BHV-1-seronegative latent carriers can be obtained experimentally. In addition, the IFN-gamma assay was able to discriminate calves possessing only passively acquired antibodies from those latently infected by BHV-1, but it could not detect seronegative latent carriers. The failure to easily detect such animals presents an epidemiological threat for the control of BHV-1 infection. [less ▲]

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See detailLes conséquences de l'infection des bovins par le virus de la rhinotrachéite infectieuse bovine
Thiry, Etienne ULg; Lemaire, Mylène; Schynts, Frédéric et al

in Point Vétérinaire (1999), 30

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See detailEtude du statut virologique d'une vache séropositive envers l'herpèsvirus bovin de type 1 et séronégative envers la glycoprotéine gE
Schynts, Frédéric; Lemaire, Mylène; Bertrand, O. et al

in Annales de Médecine Vétérinaire (1998), 142

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See detailLa glycoprotéine gE de l'herpèsvirus bovin de type 1 et les nouveaux vaccins marqués
Schynts, Frédéric; Lemaire, Mylène; Baranowski, Eric et al

in Annales de Médecine Vétérinaire (1998), 142

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