Publications scientifiques de l'EnvA
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Fetal head position matters: Association with ultrasound-measured head-perineum distance prior to operative vaginal delivery
No full textInternational audienceObjective: Identifying fetal station before operative vaginal delivery (OVD) remains a clinical challenge. Ultrasound evaluation of the head-perineum distance (HPD) is increasingly used as a tool to predict operative delivery success or failure. However, this approach does not account for fetal head position, the mechanistic characteristics of which affect fetal descent into the pelvis and could therefore affect ultrasound measurement. Objective of this study was to evaluate the association of fetal head position with ultrasound-measured HPD before OVD, according to clinical levels of station.Methods: A retrospective cross-sectional study conducted from February 2019 to May 2020 in two French tertiary hospitals. Women with singleton pregnancies of ≥34 weeks' gestation and cephalic position who had a successful OVD were included. Fetal head position was determined ultrasonographically. Station was assessed clinically and ultrasonographically (HPD).Results: 1036 OVD cases that had HPD measurements were reported. Vacuum-assisted delivery was performed in 65 % of cases, and use of forceps or spatula were reported in 35 % of cases. Fetal head position was anterior in 812 cases (78.0 %), transverse in 88 (9.0 %) and posterior in 136 (13.0 %). HPD measurement was significantly shorter in the anterior position group (37.7 mm ± 11.6) compared with the transverse (46.53 ± 12.3) and posterior (45.5 ± 11.4) groups (p < 0.001). This difference persisted after the results were stratified according to clinically identified station.Conclusion: At the same clinically identified stations, HPD measurement is influenced by fetal head position. This report highlights the importance of taking fetal head position into account when measuring HPD prior to OVD, and further studies evaluating ultrasound thresholds predictive of HPD for successful or unsuccessful operative delivery based on fetal head position are needed
Prévention et gestion des complications des castrations chirurgicales chez le cheval : approche pédagogique sous forme de cas clinique
No full textThis thesis presents a literature review on the complications of scrotal castration with second-intention wound healing in horses, adopting both preventive and curative approaches. It also includes an analysis of the regulatory aspects governing this surgical procedure, which are at the core of many veterinary liability cases. Following a concise anatomical overview, the various techniques of scrotal castration performed in field conditions are discussed, along with anesthesia and analgesia protocols and the selection of surgical instruments. Preventive strategies for complications are then developed in chronological occurrence order, first describing the complications and their diagnostic methods, then analysing the associated risk factors, and finally proposing appropriate preventive measures. The management of complications is addressed from a field-based perspective, with a focus on situations affecting the short- or medium-term prognosis or the athletic prognosis of the horse. Additionally, a set of practical recommendations is provided to support decision-making in collaboration with the owner, particularly within the framework of informed consent, a key element in preventing legal disputes. A decision-making diagram is also included in the appendix to help practitioners choose the most appropriate castration technique for each case, although the literature does not yet provide definitive conclusions regarding the impact of different techniques on complication occurrence. Finally, this thesis adopts a pedagogical approach by incorporating three interactive clinical cases. Designed to put the student or practitioner in real-life situations, these cases encourage clinical reflexion and highlight the factors of confusion and management errors that could worsen the horse's prognosis. This approach aims to enhance field decision-making and optimize both the prevention and management of scrotal castration complications in horses.Cette thèse propose une revue bibliographique sur les complications de la castration scrotale avec cicatrisation des plaies par seconde intention chez le cheval, en adoptant une approche préventive et curative. Elle intègre également une analyse des aspects réglementaires encadrant cet acte chirurgical, au cœur de nombreuses mises en cause vétérinaires. Après des rappels anatomiques concis, les différentes techniques de castration scrotale en conditions de terrain sont abordées, ainsi que les protocoles d'anesthésie et d'analgésie, et le choix du matériel chirurgical. Les stratégies de prévention des complications sont ensuite développées suivant un ordre chronologique, en décrivant d'abord les complications elles-mêmes et leurs moyens diagnostiques, puis en analysant les facteurs de risque pour enfin proposer des mesures préventives adaptées. La gestion des complications est traitée sous l'angle de la réactivité en milieu de terrain, en insistant sur les situations engageant le pronostic vital à court ou moyen terme ou le pronostic sportif du cheval. En complément, un ensemble de recommandations pratiques est proposé afin d'accompagner la prise de décision en concertation avec le propriétaire, notamment dans le cadre du consentement éclairé, élément clé de la prévention des litiges. Un diagramme décisionnel est également présenté en annexe pour aider le praticien à choisir la technique de castration la plus adaptée au contexte, bien que la littérature ne permette pas encore de conclure de manière définitive sur l'impact de chaque technique sur la survenue des complications. Enfin, cette thèse adopte une démarche pédagogique en intégrant trois cas cliniques interactifs. Conçus pour mettre l'étudiant ou le praticien en situation réelle, ces cas visent à favoriser la réflexion clinique et à souligner les facteurs de confusion et les erreurs de gestion pouvant aggraver le pronostic du cheval. Ce format a pour objectif d'améliorer la prise de décision en conditions de terrain et d'optimiser la prévention ainsi que la gestion des complications de castration chez le cheval
Obtention d’un nouvel outil cellulaire pour l’Étude des interactions spécifiques entre Toxoplasma gondii et son hôte définitif félin : les organoïdes intestinaux
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Impact of early cold temperature on genome-wide DNA methylation patterns in rainbow trout divergent lines for muscle fat content
No full textInternational audienceTo expand the availability of marketable eyed-eggs, a common practice in rainbow trout aquaculture is to store eyed-eggs at low temperatures (2-4°C) for periods of up to 2-3 weeks. Recent studies have shown that early exposure to environmental stimuli could impact fish physiology, growth, metabolism and nutrition in the mid-or long term, questioning the potential effects of such breeder practice. The objective of this study was to understand by which molecular mechanisms early cold exposure can impact fish physiology later in life, by analysing DNA methylation patterns in rainbow trout. At 17 days post fertilization (dpf), eyed-eggs from two experimental lines selected for high or low muscle lipid content, fat line and lean line, were either incubated at normal temperature (11°C) or incubated at 3°C for 15 days in 12 tanks (2 lines x 2 incubation temperatures x 3 tanks). Hatching and the rest of the rearing were performed at 11°C. Genome-wide patterns of DNA methylation were assessed by RRBS (Reduced Representation Bisulfite Sequencing) on liver samples of 48 juvenile trout (2 lines x 2 incubation temperatures x 3 tanks x 4 fish per tank) collected at 189 dpf, snap frozen in liquid nitrogen and kept at -80°C until DNA extraction. Liver was chosen as it is the central organ for intermediary metabolism. After Illumina paired-end sequencing, trimmed reads were aligned to the current Arlee rainbow trout reference genome with the bisulfite mapping tool Bismark. To avoid falsely interpreting genetic polymorphism as epigenetic variation, CpG sites intersecting with SNPs were removed. Differential methylation analyses were then performed using methylKit (qvalue<0.01, minimal methylation differences between temperature groups>20%). Identified DMCs (Differentially Methylated Cytosines) and DMRs (Differentially Methylated Regions) were finally annotated relative to gene features. Using divergent lines allowed testing the impact of the genetic background on the establishment of DNA methylation patterns in response to early cold exposure. Results suggest that the two lines responded differently, although some genes with DNA methylation varying according to cold exposure were also found in common. Ongoing interpretation of the biological pathways involved will lead to a finer understanding of underlying mechanisms
Anti-microbiota vaccine induces lysine-mediated modulation of tick immunity affecting Borrelia colonization
No full textInternational audienceTick microbiota influences Borrelia colonization, but changes in the microbiota-derived metabolite and how this affects tick physiology and vector competence is unclear. We investigated whether microbiota-induced metabolite modifications influence tick physiology and pathogen transmission. Using an anti-microbiota vaccine (live Escherichia coli) to immunize mice, we generated host antibodies that modulated the tick microbiome, decreasing bacterial abundance and increasing lysine levels in ticks. Elevated lysine correlated with increased tick weight. Lysine supplementation experiments enhanced defensin expression with DefMT6 exhibiting anti-Borrelia activity, reducing pathogen load in ticks. Our findings demonstrate that anti-microbiota vaccines induce metabolite changes, affecting tick physiology, immunity, and vector competence. These insights open new avenues for developing microbiota-targeted strategies to control tick-borne disease
Coding-complete genome sequences of hedgehog coronavirus isolated from Erinaceus europaeus in France
No full textInternational audienceThe coding-complete genome sequences of hedgehog coronavirus were retrieved from rectal swabs collected in 2022 and 2023 in France. Information on this virus is crucial to understand the pathogenicity and ecology of this Betacoronavirus
Culicoides insignis in Ecuador: Molecular identification of blood meals and detection of bluetongue virus
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Deep sequencing of 16 Ixodes ricinus ticks unveils insights into their interactions with endosymbionts
No full textInternational audienceIxodes ricinus ticks act as vectors for numerous pathogens that present substantial health threats. Additionally, they harbor vertically transmitted symbionts, some of which have been linked to diseases. The difficulty of isolating and cultivating these symbionts has hampered our understanding of their biological role, their potential to cause disease, and their modes of transmission. To expand our understanding of the tick symbiont Midichloria mitochondrii and Rickettsia helvetica , which has been linked to disease in humans, we utilized deep sequencing on 16 individual adult female ticks collected from coastal dune and forested areas in the Netherlands. By employing a combination of second- and third-generation sequencing techniques, we successfully reconstructed the complete genomes of M. mitochondrii from 11 individuals, R. helvetica from eight individuals, and the mitochondrial genome from all ticks. Additionally, we visualized the location of R. helvetica in tick organs and constructed genome-scale metabolic models (GEMs) of both symbionts to study their environmental dependencies. Our analysis revealed a strong cophylogeny between M. mitochondrii and mitochondrial genomes, suggesting frequent maternal transmission. In contrast, the absence of cophylogeny between R. helvetica and the mitochondrial genomes, coupled with its presence in the receptaculum seminis of I. ricinus females, raises the possibility of paternal transmission of R. helvetica . Notably, the genetic diversity of R. helvetica was found to be very low, except for the rickA virulence gene, where the presence of up to 13 insertions of a 33 nt-long repeat led to significant variability. However, this variation could not account for the differences in infection prevalence observed across eight distinct locations in the Netherlands. By employing deep sequencing, it becomes feasible to extract complete genomes and genetic data of symbionts directly from their host organisms. This methodology serves as a robust means to gain fresh insights into their interactions. Our observations, which suggest paternal transmission of R. helvetica , a relatively unexplored mode of transmission in ticks, require validation through experimental investigations. The genetic variations identified in the rickA virulence gene of R. helvetica have the potential to influence the infectivity and transmission dynamics of R. helvetica . IMPORTANCE Ticks are vectors of numerous human pathogens; however, the microbial interactions within ticks and the mechanisms governing pathogen transmission remain poorly understood. This study uses deep sequencing of individual Ixodes ricinus to reconstruct high-quality genomes of endosymbionts and the mitochondrion of the tick, revealing previously undetected microbial dynamics. Notably, we recovered low-abundance Rickettsia and Midichloria genomes from single ticks and present evidence that suggests paternal transmission of R. helvetica . These findings offer novel insights into the ecology and evolution of tick-associated microbes and have implications for understanding the origins and spread of tick-borne diseases
Contrasting temporal patterns and associations in Hyalomma marginatum microbial communities: key insights for the development of novel tick and tick-borne diseases control tools
No full textInternational audienceBackground: Hyalomma marginatum is an invasive tick species in southern mainland France that can carry several pathogens of human and animal interest. Because the tick microbiota represents a major factor that can potentially modulate the pathogen acquisition and transmission and might become a new control tool against ticks and tick-borne diseases, it is more than essential to identify the composition of the H. marginatum microbiota, its temporal dynamics and interactions (statistical association) between members of the tick microbiota. Methods:From monthly tick samplings performed in the same site between February to September 2022, 281 adult ticks H. marginatum were collected from horses. The microbiota composition was characterised using a high throughput sequencing approach. Different statistical analyses allowed us to assess the influence of several factors (month, season, tick sex) on the H. marginatum microbial communities and reveal potential interactions among members of these communities. Results: Apart of known obligate endosymbionts Francisella and Midichloria , and the hypothesised facultative endosymbiont ( Rickettsia ) that dominated the microbiota of H. marginatum , we detected Staphylococcus , Corynebacterium , Williamsia and Mycobacterium , usually described as commensal and/or environmental bacteria. The microbiota composition and bacterial networks differed between males and females, with males being more diverse and composed of more environmental bacteria. We reported several temporal shifts for both males and females into the microbiota composition and bacterial networks. The temporal shifts observed for females were more chaotic in terms of movements among nodes, compared to the male microbial communities that exhibited a more organised and stable dynamics. Conclusions: The influence of tick sex and time on the holobiont H. marginatum underlines the importance of the scale at which the study is conducted. Highlights Obligate endosymbionts dominate the Hyalomma marginatum microbiota Environnemental bacteria are abundant in Hyalomma marginatum microbiota Both the bacterial composition and associations differed according to the tick sex Both the bacterial composition and associations were marked by many temporal shifts for both males and females Keystone taxa in tick microbiota were highly variable from one month to anothe
Surgical Resolution of Unilateral Canine Orbital and Periorbital Lipomas in Five Dogs
No full textInternational audiencePurpose To describe five cases of orbital lipoma in which surgery was successful and no long‐term recurrence was observed. Methods A review of the medical records of dogs presenting with signs of orbital or periorbital disease and diagnosed with orbital lipoma in different practices in Spain and France was performed. Results Five cases with a mean (±SD) age of 9.32 (±1.95) years and different breeds were included. Three cases were referred for periocular mass, one for conjunctival mass, and one for exophthalmos. Computed tomography (CT) was performed in all cases and showed a well‐defined hypoattenuating mass, not continuous with the orbital fat, compatible with orbital lipoma. Surgical management was based on the size and location of the lipomas. In all cases, the mass could be removed by blunt dissection. Histopathology confirmed fibrolipoma in two cases (one case with associated bone metaplasia), one simple lipoma, one infiltrating lipoma, and one chondrolipoma. Postoperative follow‐up was uneventful, with no recurrence over 2 years after surgery in all cases. Conclusion Orbital and periorbital lipomas and their variants, although rare, may occur in dogs with clinical signs of orbital neoplasia. CT scan can predict the nature of the lesion as a lipoma. Surgical treatment is successful, with no recurrence more than 2 years after surgery. Histopathology is essential to determine the type of lipoma variant