References of "Bayrou, Calixte"
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See detailSchmallenberg virus, cyclical reemergence in the core region: a seroepidemiologic study in wild cervids, Belgium, 2012-2017.
Bayrou, Calixte ULiege; Lesenfants, Christophe ULiege; Paternostre, Julien et al

in Transboundary and emerging diseases (2021)

Schmallenberg virus emerged in 2011 in Europe. The epicenter of primordial spreading was the region straddling Germany, the Netherlands and Belgium. One of the key questions is whether the newcomer would ... [more ▼]

Schmallenberg virus emerged in 2011 in Europe. The epicenter of primordial spreading was the region straddling Germany, the Netherlands and Belgium. One of the key questions is whether the newcomer would establish a lasting presence on the continent. The apparent seroprevalence in southern Belgium wild deer populations was followed for 6 years. Two years of intense circulation were revealed, 2012 and 2016, characterized by a peak seroprevalence in the two studied populations (Capreolus capreolus and Cervus elaphus). Between the peak years and after 2016, apparent seroprevalences declined rapidly among adults and became nil among juveniles. The general pattern of apparent seroprevalence evolution observed is consistent with a cyclic circulation of Schmallenberg virus, similar to what is observed for other Orthobunyaviruses in endemic areas. These data also suggest that wild cervids play no central role in the circulation dynamics of the virus. [less ▲]

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See detailAdénocarcinomes utérins chez la chèvre : 4 cas.
Casalta, Hélène ULiege; Bayrou, Calixte ULiege; Djebala, Salem ULiege et al

in Recueil des Journées Nationales 2020 (2020, October 29)

Les atteintes tumorales de l’appareil génital sont relativement fréquentes chez la chèvre, mais les manifestations cliniques des tumeurs utérines peuvent passer inaperçues jusqu’à l’apparition de signes ... [more ▼]

Les atteintes tumorales de l’appareil génital sont relativement fréquentes chez la chèvre, mais les manifestations cliniques des tumeurs utérines peuvent passer inaperçues jusqu’à l’apparition de signes cliniques généraux peu spécifiques (anorexie, amaigrissement, ballonnement). Les quatre cas reçus à la Clinique Vétérinaire Universitaire de Liège montrent une symptomatologie fruste, une présentation tardive de symptômes touchant d’autres systèmes que le système reproducteur, illustrant bien la difficulté de poser un diagnostic précoce d’adénocarcinome utérin. L’abattement et la dilatation abdominale bilatérale sont des symptômes communs à la majorité des cas décrits. Les autopsies réalisées sur trois des quatre cas ont mis en évidence une dissémination métastatique agressive ayant entraîné la défaillance de plusieurs systèmes, et cela même dans le cas ou la stérilisation avait été relativement précoce. Une stérilisation systématique des chèvres de compagnie à la puberté pourrait être recommandée, comme c’est le cas chez les autres animaux de compagnie. [less ▲]

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See detailAnti-Schmallenberg virus activities of type I/III interferons-induced Mx1 GTPases from different mammalian species
Bayrou, Calixte ULiege; Van Laere, Anne-Sophie ULiege; Dam Van, Phai et al

Conference (2020, September 29)

• Objectives Type I/ III interferons provide powerful and universal innate intracellular defense mechanisms against viruses. Among the antiviral effectors induced, Mx proteins of some species appear as ... [more ▼]

• Objectives Type I/ III interferons provide powerful and universal innate intracellular defense mechanisms against viruses. Among the antiviral effectors induced, Mx proteins of some species appear as key components of antiviral defense. The most studied isoform, the human MxA protein, is known as the “Swiss army knife” of the antiviral response due to its ability to inhibit the cellular amplification of numerous viruses belonging to, at least, 12 different families. The bovine counterpart (the bovine Mx1 protein, BoMx1) has been shown to impair the amplification of 5 different viral family members. The Schmallenberg virus (SBV) belongs to the family Peribunyaviridae and was described for the first time in 2011. After having emerged in Northern Europe, it rapidly spread across the continent causing limited or no symptoms in adult ruminants but severe malformations in a small proportion of in utero infected fetuses. The objective of this study was to look for a cause of the ruminant sensitivity to the SBV infection in comparison to other mammal species. The question was: could the ruminant sensitivity be linked to a lack of antiviral Mx1 activity against the SBV? To answer this question, four different Mx1 isoforms originated from different mammals were studied in vitro. • Materials and methods The study was conducted in cell culture-based conditions. A lipid complex (Lipofectamine® 3000 Transfection reagent kit) transfection model was used to transiently express the Mx1 protein of four different species (the bovine, canine, equine and porcine isoforms) and compare their antiviral activities. After the transfected cells being infected with the SBV, the amount of Mx1 protein and nucleoprotein (NP) of the virus was measured using the fluorescent-activated cell sorting (FACS) technology. Human embryonic kidney cells (HEK-293T) were transfected with expression plasmids designed to express the different Mx1 isoforms tagged with the V5 epitope which was flanked on the N-terminal extremity of each Mx1 protein. The presence of the V5 epitope allowed an absolute standardization of the detection of the different V5-Mx1 isoforms. After a 24h incubation post-transfection, the cells were infected with the SBV (SBV-BH80/11-4) and cell fixation was realized after 5 hours of viral amplification. The immunolabelling was achieved using, on the one hand, a phycoerythrin (PE) conjugated monoclonal antibody targeting the V5 epitope allowing the Mx1 protein detection, and, on the other hand, a primary mouse monoclonal antibody targeting the SBV nucleoprotein associated with a goat anti-mouse IgG polyclonal antibody conjugated to the fluorescein isothiocyanate (FITC) fluorochrome. The results expressed the mean intensity of 3 independent assay (one assay comprising 3 wells for each condition and 100,000 cells analyzed per well). The statistical analysis was performed by analysis of variance (ANOVA). • Results All the tested Mx1 protein isoforms showed an antiviral effect. Indeed, in a same well, the percentage of NP expressing cells was significantly lower in the V5-Mx1 positive population than in the V5-Mx1 negative population. Among the different Mx isoforms, the antiviral effect of the canine Mx1 protein was significantly less pronounced. In the conditions of this experiment a clear dose-dependent effect was seen: an increase in the Mx1-associated fluorescence intensity was correlated with a reduction of the number of NP positive cells until an almost complete absence of the NP signal in the cells with the highest Mx fluorescence values. • Conclusions The bovine species sensitivity to the SBV infection is not linked to a lack of antiviral activity of the bovine Mx1 protein against the virus. The experiment corroborates the results showing that the Mx1 proteins have been selected during evolution to efficiently inhibits the amplification of a large diversity of viruses including the Peribunyaviridae family. The dose-dependent effect we herein described could reflect an unknown specific mechanism of the SBV inhibition by the Mx1 protein. [less ▲]

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See detailContribution à la biologie du virus de Schmallenberg chez les ruminants
Bayrou, Calixte ULiege

Doctoral thesis (2020)

On the autumn 2011, the Friedrich Loeffler Institute (Germany) isolate the genetic material of a hitherto unknown virus which is associated with an unexplained syndrome of fever, drop of milk and diarrhea ... [more ▼]

On the autumn 2011, the Friedrich Loeffler Institute (Germany) isolate the genetic material of a hitherto unknown virus which is associated with an unexplained syndrome of fever, drop of milk and diarrhea reported in the dairy farms from the Netherlands and Northwest Germany. The newcomer was named Schmallenberg virus based on the geographical origin of the first positive samples. It belongs to the Orthobunyavirus genus. For the first time in Western Europe, an arbovirus of this group circulates among ruminants. Such an emergence is, by many ways, similar to the type 8 Bluetongue virus emergence in 2006 and is one indication that the global infectious diseases dynamic is changing in Europe. Thus, understanding and documenting the Schmallenberg virus emergence, in that context, is of great importance. The present thesis is part of this approach and aim to contribute to the knowledge and the understanding of the virus biology and the associated disease. It is comprised of three studies that investigate the problematic at three different levels. The first study is a description of the lesions found in the bovine fetus after the transplacental passage of the virus. This study is a confirmation that the lesions are limited to the neurologic and myo-arthro-skeletal systems. The two characteristic lesions associated with the in-utero infection are the micromyelia and the arthrogryposis. The study strongly suggests that the key element of the pathogeny of these lesions is the virus-induced destruction of the spinal cord motoneurons. The second study follows the seroprevalence of the virus in the wild deer populations in Wallonia from 2012 to 2017. The study substantiates the hypothesis of a hypo-endemic installation of the virus with cyclic pulsations. This particular endemic state has been described for close viruses. It is characterized by several years of low-level circulation followed by one year of higher circulation. Moreover, according to this study, deer are not the main reservoir of the virus. The populations of wild ruminants do participate to the circulation of the virus. Nevertheless, they have a minor impact on the global dynamic of the Schmallenberg virus circulation. The third study focuses on one of the main effectors of the interferon response, the Mx1 protein. The aim is to describe the effect of the latter on the viral cycle. By comparing, in vitro, Mx1 proteins from different mammals (bovine, canine, equine, porcine Mx proteins), the study shows an antiviral effect for the four tested proteins. However, the canine Mx1 is significantly less active. The second main result is the observation of a not previously described dose-dependent effect of the Mx antiviral effect. Those three studies, because they explore the Schmallenberg virus biology from different angles, provide a broad overview of the questions raised by the Schmallenberg virus emergence. [less ▲]

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See detailInfectious Agents Identified by Real-Time PCR, Serology and Bacteriology in Blood and Peritoneal Exudate Samples of Cows affected by Parietal Fibrinous Peritonitis after Caesarean Section
Djebala, Salem ULiege; Evrard, Julien; Gregoire, Fabien et al

in Veterinary Sciences (2020), 7

The aim of this study was to identify the pathogens potentially involved in parietal fibrinous peritonitis (PFP). PFP is a complication of laparotomy in cattle, characterized by an accumulation of exudate ... [more ▼]

The aim of this study was to identify the pathogens potentially involved in parietal fibrinous peritonitis (PFP). PFP is a complication of laparotomy in cattle, characterized by an accumulation of exudate inside a fibrinous capsule. We have studied 72 cases of PFP in Belgian blue cows, confirmed by a standard diagnostic protocol. Blood was collected to evaluate the presence of antibodies for Mycoplasma bovis (M. bovis), Coxiella burnetii (C. burnetii) and Bovine Herpesvirus 4 (BoHV4) by enzyme-linked immunosorbent assays. Peritoneal exudate was obtained from the PFP cavity to perform bacteriological culture, and to identify the DNA of M. bovis, C. burnetii and BoHV4 using real time polymerase chain reaction (qPCR). Bacteriological culture was positive in most peritoneal samples (59/72); Trueperella pyogenes (T. pyogenes) (51/72) and Escherichia coli (E. coli) (20/72) were the most frequently identified. For BoHV4, the majority of cows showed positive serology and qPCR (56/72 and 49/72, respectively). Contrariwise, M. bovis (17/72 and 6/72, respectively) and C. burnetii (15/72 and 6/72, respectively) were less frequently detected (p < 0.0001). Our study proves that PFP can no longer be qualified as a sterile inflammation. Moreover, we herein describe the first identification of BoHV4 and C. burnetii in cows a ected by PFP. [less ▲]

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See detailProceedings of the 7th FARAH-Day
Bayrou, Calixte ULiege; Cesarini Latorre, Carlota ULiege; Delguste, Catherine ULiege et al

Book published by Presses de la Faculté de Médecine vétérinaire de l'Université de Liège (2020)

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See detailComparison between generalised peritonitis and parietal fibrinous peritonitis in cows after caesarean section
Djebala, Salem ULiege; Evrard, Julien; Moula, Nassim ULiege et al

in Veterinary Record: Journal of the British Veterinary Association (2020)

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See detailNon-Steroid Anti-Inflammatory Drugs utilization during bovine elective caesarean section in Wallonia
Coria, Elise; Moula, Nassim ULiege; Touati, Kamal ULiege et al

Poster (2019, November 08)

Non-Steroid Anti-Inflammatory Drugs utilization during bovine elective caesarean section in Wallonia

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See detailManagement of an infected non-penetrating thoracic wound in a Belgian Blue calf using honey and a tie-over bandage
Eppe, Justine ULiege; Coria, Elise ULiege; Casalta, Hélène ULiege et al

Poster (2019, November 08)

Management of an infected non-penetrating thoracic wound in a Belgian Blue calf using honey and a tie-over bandage

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See detailProphylactic antibiotic usage by Belgian veterinarians and breeders during elective caesarean section in Belgian Blue cattle
Djebala, Salem ULiege; Moula, Nassim ULiege; Bayrou, Calixte ULiege et al

Conference (2019, November)

Prophylactic antibiotic usage by Belgian veterinarians and breeders during elective caesarean section in Belgian Blue cattle

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See detailSyndrome de détresse respiratoire aiguë du nouveau-né : du cas individuel au troupeau
Bayrou, Calixte ULiege; Casalta, Hélène ULiege; Guyot, Hugues ULiege et al

in JNGTV : La rurale dans tous ses états (2019, May 16)

Le syndrome de détresse respiratoire aiguë des veaux nouveau-nés est parfois sous-estimé dans les exploitations ; ces veaux présentant une sévère tachycardie-tachypnée étant trop rapidement classés dans ... [more ▼]

Le syndrome de détresse respiratoire aiguë des veaux nouveau-nés est parfois sous-estimé dans les exploitations ; ces veaux présentant une sévère tachycardie-tachypnée étant trop rapidement classés dans les « veaux cardiaques ». Or l’origine carentielle de ce syndrome en fait un signal d’alerte important pour le praticien. Cet exposé illustre, dans une première partie, la symptomatologie et les traitements envisageables. Dans la deuxième partie la partie immergée de l’iceberg sera présentée : la pathogénie du syndrome et sa double origine carentielle, Iode et Sélénium, en insistant sur l’importance de la forme organique dans la complémentation en Sélénium. [less ▲]

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See detailHost-dependence of in vitro reassortment dynamics among the Sathuperi and Shamonda Simbuviruses.
Coupeau, Damien; Bayrou, Calixte ULiege; Baillieux, Pierre et al

in Emerging Microbes and Infections (2019), 8(1), 381-395

Orthobunyaviruses are arboviruses (Arthropod Borne Virus) and possess multipartite genomes made up of three negative RNAs corresponding to the small (S), medium (M) and large (L) segments. Reassortment ... [more ▼]

Orthobunyaviruses are arboviruses (Arthropod Borne Virus) and possess multipartite genomes made up of three negative RNAs corresponding to the small (S), medium (M) and large (L) segments. Reassortment and recombination are evolutionary driving forces of such segmented viruses and lead to the emergence of new strains and species. Retrospective studies based on phylogenetical analysis are able to evaluate these mechanisms at the end of the selection process but fail to address the dynamics of emergence. This issue was addressed using two Orthobunyaviruses infecting ruminants and belonging to the Simbu serogroup: the Sathuperi virus (SATV) and the Shamonda virus (SHAV). Both viruses were associated with abortion, stillbirth and congenital malformations occurring after transplacental transmission and were suspected to spread together in different ruminant and insect populations. This study showed that different viruses related to SHAV and SATV are spreading simultaneously in ruminants and equids of the Sub-Saharan region. Their reassortment and recombination potential was evaluated in mammalian and in insect contexts. A method was set up to determine the genomic background of any clonal progeny viruses isolated after in vitro coinfections assays. All the reassortment combinations were generated in both contexts while no recombinant virus was isolated. Progeny virus populations revealed a high level of reassortment in mammalian cells and a much lower level in insect cells. In vitro selection pressure that mimicked the host switching (insect-mammal) revealed that the best adapted reassortant virus was connected with an advantageous replicative fitness and with the presence of a specific segment. [less ▲]

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See detailProceedings of the 6th FARAH-Day
Bayrou, Calixte ULiege; Delguste, Catherine ULiege; Douny, Caroline ULiege et al

Book published by Presses de la Faculté de Médecine vétérinaire de l’Université de Liège (2019)

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See detailProphylactic antibiotic usage by Belgian veterinarians during elective caesarean section in Belgian blue cattle
Djebala, Salem ULiege; Moula, Nassim ULiege; Bayrou, Calixte ULiege et al

in Preventive Veterinary Medicine (2019), 172

The use of prophylactic antibiotics in veterinary surgery reduces the occurrence of postoperative complications. In order to limit the development of antimicrobial resistance in bacteria and to maximize ... [more ▼]

The use of prophylactic antibiotics in veterinary surgery reduces the occurrence of postoperative complications. In order to limit the development of antimicrobial resistance in bacteria and to maximize therapy efficacy, antibiotics should be used prudently and efficiently. A survey was sent to Wallonian rural veterinarians in order to assess the use of antibiotics before, during and after bovine elective caesarean section, the most common surgical procedure in Belgian rural practice. Results were analysed in the light of the current guidelines formulated by the Belgian Centre of Expertise on Antimicrobial Consumption and Resistance in Animals. Among 380 contacted veterinarians, 113 answered the survey. All veterinarians use antibiotics during caesarean section. Veterinarians predominantly use penicillin as the first drug of choice, whereas a minority use drugs considered as second or third choice, such as amoxicillin, oxytetracyclin or lincomycin-spectinomycin. Also, 31/113 veterinarians simultaneously use molecules from different antibiotic classes. The majority (100/113) of veterinarians inject antibiotics during or after surgery, while a minority (13/113) administer antibiotics preoperatively. Most veterinarians (67/113) limit the duration of their antibiotic treatment to 1 day. Considering the administration route, most veterinarians (88/113) systematically use the intraperitoneal injection route, which is not registered. Intramuscular injection and injection between muscle layers during surgery are carried out by 82/113 and 43/113 respondents, respectively. Twenty-two respondents apply intra-uterine antibiotics. Most veterinarians (87/113) combine several administration routes. The dosage of antibiotics varies enormously and excessive injection volumes are common, especially when multiple injection routes are combined. Our results show a striking lack of consistency in the antibiotic therapy during elective CS by rural veterinarians. Whereas the drug of choice and the treatment duration were largely in line with the current guidelines, this is certainly not the case for the dosage and the administration route. The intraperitoneal injection of antibiotics cannot be justified. Incorrect dosage of antibiotics should be avoided at all cost. The use of second and third line molecules and the simultaneous use of different antibiotic classes should be discouraged. A major challenge lies in the education of veterinary students and the sensitization of practitioners to avoid or unlearn unnecessary habits concerning antibiotic use. Finally, more clinical trials are needed in order to refine the current guidelines for antibiotic use and to determine the optimal drug of choice, treatment moment and application route in elective caesarean section in cattle. © 2019 Elsevier B.V. [less ▲]

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See detailThe role of roughage provision on the absorption and disposition of the mycotoxin deoxynivalenol and its acetylated derivatives in calves: from field observations to toxicokinetics.
Valgaeren, Bonnie; Theron, Leonard; Croubels, Siska et al

in Archives of Toxicology (2019)

A clinical case in Belgium demonstrated that feeding a feed concentrate containing considerable levels of deoxynivalenol (DON, 1.13 mg/kg feed) induced severe liver failure in 2- to 3-month-old beef ... [more ▼]

A clinical case in Belgium demonstrated that feeding a feed concentrate containing considerable levels of deoxynivalenol (DON, 1.13 mg/kg feed) induced severe liver failure in 2- to 3-month-old beef calves. Symptoms disappeared by replacing the highly contaminated corn and by stimulating ruminal development via roughage administration. A multi-mycotoxin contamination was demonstrated in feed samples collected at 15 different veal farms in Belgium. DON was most prevalent, contaminating 80% of the roughage samples (mixed straw and maize silage; average concentration in positives: 637 +/- 621 microg/kg, max. 1818 microg/kg), and all feed concentrate samples (411 +/- 156 microg/kg, max. 693 microg/kg). In order to evaluate the impact of roughage provision and its associated ruminal development on the gastro-intestinal absorption and biodegradation of DON and its acetylated derivatives (3- and 15-ADON) in calves, a toxicokinetic study was performed with two ruminating and two non-ruminating male calves. Animals received in succession a bolus of DON (120 microg/kg bodyweight (BW)), 15-ADON (50 microg/kg BW), and 3-ADON (25 microg/kg) by intravenous (IV) injection or per os (PO) in a cross-over design. The absolute oral bioavailability of DON was much higher in non-ruminating calves (50.7 +/- 33.0%) compared to ruminating calves (4.1 +/- 4.5%). Immediately following exposure, 3- and 15-ADON were hydrolysed to DON in ruminating calves. DON and its acetylated metabolites were mainly metabolized to DON-3-glucuronide, however, also small amounts of DON-15-glucuronide were detected in urine. DON degradation to deepoxy-DON (DOM-1) was only observed to a relevant extent in ruminating calves. Consequently, toxicity of DON in calves is closely related to roughage provision and the associated stage of ruminal development. [less ▲]

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See detailLa ténotomie chez le veau
Eppe, Justine ULiege; Djebala, Salem ULiege; Bayrou, Calixte ULiege et al

in Point Vétérinaire: Expert Rural (2019)

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See detailTraitement chirurgical de l’arthrite septique chez le veau
Djebala, Salem ULiege; Van Leeuw, Corine ULiege; Bayrou, Calixte ULiege et al

in Point Vétérinaire: Expert Rural (2019)

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