Colostral antibody induced interference of inactivated bluetongue serotype-8 vaccines in calves

Since its introduction into northern Europe in 2006, bluetongue has become a major threat to animal health. While the efficacy of commercial vaccines has been clearly demonstrated in livestock, little is known regarding the effect of maternal immunity on vaccinal efficacy. Here, we have investigated the duration and amplitude of colostral antibody-induced immunity in calves born to dams vaccinated against bluetongue virus serotype 8 (BTV-8) and the extent of colostral antibody-induced interference of vaccination in these calves. Twenty-two calf-cow pairs were included in this survey. The median age at which calves became seronegative for BTV was 84 and 112 days as assayed by seroneutralisation test (SNT) and VP7 BTV competitive ELISA (cELISA), respectively. At the mean age of 118 days, 13/22 calves were immunized with inactivated BTV-8 vaccine. In most calves vaccination elicited a weak immune response, with seroconversion in only 3/13 calves. The amplitude of the humoral response to vaccination was inversely proportional to the maternal antibody level prior to vaccination. Thus, the lack of response was attributed to the persistence of virus-specific colostral antibodies that interfered with the induction of the immune response. These data suggest that the recommended age for vaccination of calves born to vaccinated dams needs to be adjusted in order to optimize vaccinal efficacy

Anatomical distribution of Toxoplasma gondii in naturally and experimentally infected lambs

Consumption of raw or undercooked meat containing Toxoplasma gondii tissue cysts is one of the main sources of infection for humans worldwide. Among the various species intended for human consumption, sheep appear to be a high risk for human infection. The present study focused on the detailed anatomical distribution of Toxoplasma gondii in naturally and experimentally infected lambs using fresh and frozen samples of various pieces of meat, from a public health perspective. The first objective was to rank the edible parts intended for human consumption according to the detectable parasite burden by real-time PCR targeting the 529-bp repeated element. The second objective was to evaluate the impact of freezing by comparing the detection efficiency of the quantitative PCR between fresh and frozen tissues, as imports of lamb carcasses/cuts may arrive frozen or chilled. The highest estimated parasite loads were observed in skeletal muscles, and more particularly in edible portions such as quadriceps femoris muscle, intercostal muscles, deltoid muscle and diaphragm, with a significant difference in detectable parasite burden between fresh and frozen samples (p < 0.0001) or natural and experimental infection (p < 0.0001). Thoracic and pelvic limbs (3278–1048 parasites/g muscle) were ranked at the top of the list. Toxoplasma gondii DNA was detected in all the edible parts of lamb studied. These results suggest that lamb meat represents a risk for consumers. Further investigations are needed in order to confirm these differences in larger numbers of animals and in different breeds

Emergence and re-emergence of two major diseases in France (bluetongue) and in Mauritius (foot-and-mouth)

L’émergence en France continentale de la fièvre catarrhale ovine (FCO) causée en 2006 par le virus de sérotype 8 (BTV-8) puis en 2007, par le virus de sérotype 1 (BTV-1) a constitué une surprise totale. Fin 2012, six ans après l’introduction de la FCO, la France a été déclarée indemne de cette maladie. Pourtant, fin août 2015, le BTV-8 a fait sa réapparition dans le centre de la France. En 2016 notre laboratoire a isolé à nouveau ce virus. En Corse, un virus de sérotype 4 (BTV-4) fut identifié le 1er décembre 2016 à partir de prélèvements de moutons. D’autre part, en 2016, nous avons identifié un virus de la fièvre aphteuse de sérotype O à Maurice. Cette présentation décrira les conditions de détection de ces virus ainsi que les résultats des analyses phylogénétiques.The emergence of Bluetongue (BT) in continental France (caused by virus of serotype 8 (BTV-8) in 2006 and virus of serotype 1 (BTV-1) in 2007) was a total surprise. End of 2012, six years after the introduction of BT, France was declared free from this disease. However, at the end of August 2015, the BTV-8 made its reappearance in the center of France. In 2016, our laboratory re-isolated this virus. In Corsica, a virus of serotype 4 was identified on 1st December 2016 from sheep samples. On another hand, in 2016, we identified a virus of Foot-and-Mouth disease serotype O in Mauritius. This presentation will describe the conditions of the detection of these viruses as well as the results of phylogenetic analyzes

Impact of Bluetongue Virus serotype 8 (BTV-8) in goats (Capra hircus)

La Fièvre Catarrhale Ovine est une arbovirose due à un Orbivirus touchant les ruminants. Récemment, une épizootie majeure, notamment due au sérotype 8 du virus (BTV-8), a touché les ruminants Européens. Ce sérotype a présenté plusieurs particularités telles que le spectre d’hôte original, et la transmission transplacentaire. L’impact de l’infection par le BTV-8 chez le caprin a été étudiée dans ce travail d’un point de vue clinique, virologique, hématologique et sérologique, et notamment pour ce dernier aspect à travers le développement de deux outils sérologiques. L’impact d’une infection maternelle sur le fœtus a également été étudié.Ces travaux ont confirmé que l’impact de l’infection par le BTV-8 chez les caprins est modéré, tant d’un point de vue clinique que d’un point de vue hématologique. Ce travail a également permis de faire ressortir plusieurs connaissances nouvelles: un impact modéré sur les comptages leucocytaires ; une transmission transplacentaire du virus lors d’infection en milieu de gestation ; une détection du virus dans la semence ; une possible transmission « directe », non vectorielle.Ces 3 dernières constatations n’avaient jusqu’alors pas été rapportées dans la littérature chez les caprins, mais avaient été observées chez les ovins et les bovins. Ceci confirme que, même si les caprins sont des animaux sensibles mais que l’impact clinique est limité, la plupart des caractéristiques faisant la spécificité de l’infection par la souche européenne du BTV-8 peuvent également être retrouvées dans cette espèce. Néanmoins, l’absence de description de ces particularités dans des conditions d’infection naturelle ne permet pas de conclure quant à leur impact sur le terrain.Des outils sérologiques ont été également développés afin d’étudier les propriétés antigéniques des protéines virales chez le caprin. La production des protéines recombinantes NS1, NS3, VP7 et VP2 en système baculovirus, et de la protéine NS2 en système E. coli, ont permis l’obtention de protéines recombinantes. Ces 5 protéines recombinantes ont permis le développement de tests sérologiques permettant d’étudier leurs propriétés antigéniques et la cinétique d’apparition des anticorps après vaccination ou/et infection par le BTV-8 chez le caprin.Dans un premier temps, des tests ELISA indirect NS1, NS2, NS3, VP7 et VP2 ont été développés, et la capacité des tests ELISA NS et VP7 à permettre une différenciation entre les animaux infectés et vaccinés a été évaluée. Cependant, des anticorps anti-NS2 et NS3 ont été détectés dans les sérums d’animaux vaccinés et une faible réponse obtenue en ELISA NS1 chez les animaux infectés rend difficile l’utilisation d’un test ELISA DIVA basé sur ces 3 protéines non structurales. Enfin, une réponse en anticorps anti-VP2 est détectée par le test ELISA VP2 après vaccination et après épreuve virulente, suggérant une détection d’anticorps spécifiques de type par ce test.Dans un second temps, un test Luminex multiplex, basé sur l’utilisation des protéines VP7 et VP2 a été développé. Le Luminex VP7 présente une très bonne corrélation avec l’ELISA VP7 lorsque les sérums d’animaux infectés sont testés, avec une aire sous la courbe de 0,987. Les performances de ce test paraissent cependant modérées lorsque des sérums issus d’animaux ayant reçu une unique injection vaccinale sont testés. Le Luminex VP2 présente des performances également excellentes, avec une aire sous la courbe de 0,978. Les VPP et VPN ont été calculées pour des prévalences très faibles (0,5%, correspondant à la prévalence devant être détectée par le screening sérologique d’animaux sentinelles) : la VPP est alors très faible mais la VPN est très élevée (99,99% pour VP7, 99,95% pour VP2). Le test Luminex multiplex développé, caractérisé par une VPN très élevée, permet d’exclure avec confiance la présence du BTV-8 dans une région indemne lors de résultat négatif, correspondant parfaitement aux objectifs assignés.Bluetongue is an infectious non contagious arbovirosis caused by Bluetongue virus (BTV), belonging to the genus Orbivirus. Recently, a major epizooty, due to BTV-8, was encountered in European ruminants. This serotype presented several original features such as an original host spectrum and transplacental transmission. This work consisted in studying the impact of BTV-8 infection in goats from a clinical, virological, haematological and serological (after development of two new serological tests) point of view, because of the lack of knowledge in this specie. The impact on foetuses of infection during gestation was also studied.The different animal studies realised confirmed that the BTV-8 infection has a moderate impact in goats from a clinical and haematological point of view. These studies led to obtain new information about BTV-8 impact: moderate impact on leucocytes counts; transplacental transmission of the virus when infection occurs in mid-pregnancy; detection of BTV-8 in bucks’ semen; direct, non vectorial transmission. The last 3 results had never been described in goats with BTV-8 before but had been encountered in sheep and cattle: it proves that, even if goats are susceptible to the infection but are less affected by the virus, most of feature of BTV-8 North European strain can also be encountered in this specie. However, these features have not been described in natural conditions, making impossible to conclude on their impact in the field.In a second part of this thesis, serological tool have been developed in order to study antigenic properties of viral proteins in goats. Recombinant proteins NS1, NS3, VP7 and VP2 were produced in baculovirus system, while NS2 was produced in E. coli system. These recombinant proteins were used to develop serological test in order to study antigenic properties and the kinetic of antibodies response against this 5 proteins after vaccination against and infection by BTV-8 in goats.In a first part, indirect ELISA NS1, NS2, NS3, VP7 and VP2 were developed, and the opportunity to develop DIVA ELISA test using NS and VP ELISA was evaluated. However, detection of antibodies against NS2 and NS3 in vaccinated animals, and the difficulties to detect antibodies against NS1 in infected animals led us to conclude that a DIVA ELISA test using non-structural proteins was difficult. Finally, it was possible to detect antibodies against VP2 in infected and vaccinated animals using our VP2 ELISA, suggesting a detection of antibodies specific of serotype by this test.In a second part, a multiplex Luminex test, using VP7 and VP2, was developed. This test has, for VP7 detection, a strong correlation with cELISA VP7, with an area under the curve of 0.987. Luminex VP7 performance is moderate when sera from goats having only one vaccine administration were tested. Concerning Luminex VP2, test performance are also excellent with an area under the curve of 0.978. When a prevalence of 0.5% was applied (prevalence that should be detected by serological screening in Europe), de predictive negative value was very high (99.99% for Luminex VP7; 99.95% for Luminex VP2). The Luminex test developed, with a very high PNV, can exclude with a high level of confidence the presence of BTV-8 in a free-area

Skeletal Muscle Microvasular (Dys)Function: Mechanisms and Therapeutics

Oxygen (O2) plays a crucial role in the energy metabolism of complex multicellular life on earth. Due to the small and finite energy stores in the body, fine-tuned changes within the body are required to meet metabolic demand during skeletal muscle contractions, such as during exercise and activities of daily living. The skeletal muscle microcirculation is one of the last steps in the O2 transport pathway from the lungs to muscle cells and represents the largest surface area for O2 and substrate exchange. When skeletal muscle O2 uptake increases during contractions to meet metabolic demand, there must be an increase in muscle O2 delivery. To achieve these elevations in O2 delivery, vessel (arteriole) diameter in the microcirculation is increased, known as vasodilation. This process in the skeletal muscle microcirculation is regulated by several factors, such as neurohumoral, mechanical, endothelial, paracrine, and metabolic influences, which are imperative in properly regulating O2delivery at rest and during muscular contractions. Two vasodilatory pathways of interest in this dissertation are the cyclooxygenase (COX) and nitric oxide (NO) vasodilatory pathways.The primary aim of my dissertation studies was to determine the mechanisms that modulate skeletal muscle oxygenation in health and to define the impact of a potentially effective intervention, whole-body chronic heat therapy (HT), to treat heart failure with preserved ejection fraction (HFpEF). In Chapter 2, we report that acute selective COX-2 inhibition had no effect on resting or exercising skeletal muscle microvascular oxygenation, pulmonary oxygen uptake, or exercise tolerance in healthy young humans. In Chapter 3, we report that NO, via phosphodiesterase type 5 inhibition, regulates myocyte O2transport at rest and during recovery from muscle contractions in healthy young rats. In Chapter 4, we show that whole-body chronic HT promotes central and peripheral adaptations, which impact positively exercise tolerance in a pre-clinical rat model of HFpEF. Specifically, whole-body chronic HT had beneficial influences on exercise tolerance, skeletal muscle oxygenation from rest to contractions (driven, at least in part, by enhanced NO bioavailability), body composition, and cardiac function. Chapter 5 is a summary of the results and limitations of the projects presented in Chapters 2-4, with a brief discussion of potential future research directions

Importance de

Mycoplasma bovis est une bactérie fréquemment impliquée dans les troubles respiratoires des jeunes bovins. Si elle peut à elle seule conduire à des lésions pulmonaires, elle est souvent considérée comme un agent potentialisateur, favorisant le développement d’autres agents secondaires. Son impact diffère selon les systèmes de production : des études de séroprévalence montrent une importance modérée mais variable en système naisseur, alors que son impact est plus fort dans les ateliers d’engraissement de veaux de boucherie.Mycoplasma bovis est une bactérie fréquemment impliquée dans les troubles respiratoires des jeunes bovins. Son importance est néanmoins variable selon les systèmes de production, avec un impact plus fort dans les ateliers d’engraissement de veaux de boucherie

Vacciner les mères et les veaux pour gérer des BPIE : qu’en attendre ?

La prévention des affections respiratoires des jeunes bovins repose en grande partie sur la vaccination des animaux à risque. Néanmoins certaines limites, liées entre autres choses à l’âge où la vaccination peut être mise en œuvre ou encore le délai d’instauration de l’immunité, sont notées dans certains cheptels où les affections surviennent chez les très jeunes animaux. Depuis quelques années se développe en élevage une vaccination plus large que la vaccination des seuls bovins à risque de maladie respiratoire, avec une vaccination des mères en complément de la vaccination des veaux. Cet article se propose de faire la synthèse sur les effets à en attendre.La vaccination contre les affections respiratoires des veaux et jeunes bovins peut présenter certaines limites : la réalisation d’une vaccination des mères en complément de la vaccination des animaux à risque peut favoriser une moindre incidence de la maladie

The effects of acute caffeine ingestion on repeated-sprint performance in college-aged non-athletes

Advisors: Peter J. Chomentowski.Committee members: Clayton L. Camic; Steven M. Howell; Shuqi Zhang.Includes illustrations.Includes bibliographical references.Caffeine is one of the most widely used drugs in the world, commonly ingested in coffee, tea, soda, chocolate, and energy drinks, due to its benefits of increasing mental and physical capabilities. Caffeine has also been commonly used as an ergogenic aid when performing repeated-sprint activity. PURPOSE: The purpose of this study is to examine the effects of 200 mg of caffeine during repeated-sprint activity on heart rate, rating of perceived exertion, blood lactate concentration, and sprint time. METHODS: Thirty-two students (Age: 22.19 ± 2.29 years; Height: 170.58 ± 10.18 cm; Weight: 74.78 ± 12.76 kg; BMI: 25.59 ± 2.78) participated in the study. The study followed a randomized crossover trial, in which each participant ingested either 200 mg of caffeine (CAF) or placebo (PLA) 45 minutes prior to each of the two exercise sessions. The sprinting protocol consisted of three sets of six maximal-effort 30-meter sprints. Each single sprint covered a 15-meter distance between the starting line and the secondary marker, such that each subject sprinted down to the secondary marker and back to the starting line. Each of the six sprints in a set were separated by a total of 20 seconds using an active recovery modality. Following each sprint set, heart rate, blood lactate concentration, sprint time, and the rating of perceived exertion were recorded. RESULTS: The caffeine trials were not significantly different than the placebo trials for heart rate and the rating of perceived exertion. However, for the rating of perceived exertion, there was a main effect for time [F(3,93) = 292.810, p < 0.001]. The caffeine trials (Resting: 1.30 ± 0.52 mmol/L; Set 1: 11:33 ± 2.38 mmol/L; Set 2: 13.26 ± 3.02 mmol/L; Set 3: 13.67 ± 2.49 mmol/L) elicited increased blood lactate concentrations compared to the placebo trials (Resting: 1.37 ± 0.53 mmol/L; Set 1: 9.24 ± 2.43 mmol/L; Set 2: 11.46 ± 2.87 mmol/L; Set 3: 11.83 ± 2.55 mmol/L). The caffeine trials (Set 1: 6.78 ± 0.58 secs; Set 2: 6.81 ± 0.55 secs; Set 3: 6.85 ± 0.57 secs) also produced a decreased average sprint time compared to the placebo trials (Set 1: 7.00 ± 0.64 secs; Set 2: 7.02 ± 0.62 secs; Set 3: 7.12 ± 0.63 secs). For the average sprint time, there were significant main effects for condition [F(1,31) = 36.839, p < 0.001] and time [F(2,62) = 5.806, p = 0.006]. CONCLUSION: Caffeine supplementation at a dose of 200 mg elicits an increase in repeated-sprint ability in college-aged non-athletes.M.S. Ed. (Master of Education