Publications scientifiques de l'EnvA
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Étude de l'infectiosome et déterminants des processus infectieux de la faune sauvage : exemple des populations de vertébrés marins des îles subantarctiques
No full textDescribing and understanding the factors that affect the circulation of infectious agents in animal populations and their effects on their demography is important from a fundamental as well as an applied perspective. Wild vertebrate populations in polar areas are increasingly subject to threats from infectious diseases, in addition to other environmental threats (introduced species, climate change, fisheries-associated mortalities), and it is critical to have baseline data on the eco-epidemiological status of these systems and understand their dynamics. Colony-breeding vertebrate populations are particularly important to study in this context because they can experience mortality events of hundreds to thousands of individuals, and are distributed in discrete units within and between which the transmission of infectious agents can be affected by various complex processes. In this context, the PhD will focus on the ecology of the circulation of infectious agents in colonial birds and marine mammals, particularly in sub-Antarctic islands. The aim is to study the exposure of host species to potentially pathogenic infectious agents, but also to test hypotheses based on knowledge of the life history traits of host species, the ecology of vectors (ticks in particular), and the characteristics of infectious agents. The host species involved will be species living in dense colonies (black-browed albatrosses, king penguins, gorfous, cormorants, fur seals, elephant seals) and predatory species of other birds and scavengers (subantarctic skuas, giant petrels). The use of certain species as sentinels will be explored, in parallel with the transmission processes of agents within and between populations. The infectious agents considered will be bacteria (e.g., Pasteurella multocida, Erysipelothrix spp, Borrelia budgoferi, Brucella spp, Chlamydia sp.), viruses (e.g., Flavivirus, AIV, paramyxovirus). The sampling carried out will allow us to work on a hierarchy of spatial scales (notably within and between the islands of the French Southern Territories, Crozet, Kerguelen, Saint Paul and Amsterdam; within and in comparison with other sub-Antarctic islands, notably the Falklands).La description et la compréhension des facteurs qui affectent la circulation d'agents infectieux dans les populations animales et leurs effets sur leur démographie sont importantes d'un point de vue fondamental, mais aussi appliqué. Les populations de vertébrés sauvages vivant dans les zones polaires sont de plus en plus sujettes à des menaces dues à des maladies infectieuses, en plus d'autres menaces environnementales (espèces introduites, changement climatique, mortalités associées aux pêcheries), et il est primordial de disposer de données de base sur l'état éco-épidémiologique de ces systèmes et de comprendre leurs dynamiques. Les populations de vertébrés se reproduisant en colonies sont particulièrement importantes à étudier dans ce contexte car elles peuvent subir des épisodes de mortalités pouvant atteindre des centaines voire des milliers d'individus, et elles sont distribuées en unités discrètes au sein et entre lesquelles la transmission d'agents infectieux peut être affectée par différents processus complexes. Dans ce contexte, le doctorat portera sur l'écologie de la circulation d'agents infectieux chez les oiseaux et mammifères marins coloniaux, en particulier des îles subantarctiques. Il s'agit d'étudier l'exposition d'espèces hôtes à des agents infectieux potentiellement pathogènes, mais aussi de tester des hypothèses reposant sur une connaissance des traits d'histoire de vie des espèces d'hôtes, de l'écologie de vecteurs (tiques notamment), et de caractéristiques des agents infectieux. Les espèces d'hôtes impliquées seront des espèces vivant en colonies denses (albatros à sourcil noir, manchot royaux, gorfous, cormorans, otaries à fourrure, éléphant de mer) et des espèces prédatrices d'autres oiseaux et charognardes (labbes subantarctiques, pétrels géants). L'utilisation de certaines espèces comme sentinelles sera explorée, en parallèle des processus de transmission d'agents au sein et entre populations. Les agents infectieux considérés seront notamment des bactéries (e.g., Pasteurella multocida, Erysipelothrix spp, Borrelia budgoferi, Brucella spp, Chlamydia sp.), des virus (e.g., Flavivirus, AIV, paramyxovirus). L'échantillonnage réalisé permettra de travailler à une hiérarchie d'échelles spatiales (notamment au sein et entre les îles des terres australes françaises, Crozet, Kerguelen, Saint Paul et Amsterdam ; au sein et en comparaison avec d'autres d'îles sub-antarctiques, notamment les Malouines)
From mice to rhinos: Whole-organ quantification of 3D mammalian placental structure using correlative multiscale imaging
No full textInternational audienceThe mammalian placenta displays extraordinary structural diversity across scales of measurement, yet the quantitative basis and functional consequences of this variation remain poorly understood. Traditional approaches rely on qualitative categories or simple metrics such as length or depth which obscure the complexity of three-dimensional (3D) tissue architecture. Here, we review methods for quantifying whole-organ placental volume, surface area, and vascular organisation, highlighting trade-offs between speed, expense, labour, precision, scalability, destructivity, and specificity. We then demonstrate how correlative multiscale 3D imaging techniques can overcome these limitations, enabling whole-organ quantification across species spanning several orders of magnitude in placental volume-from mouse to rhinoceros. Using integrated workflows that combine X-ray microfocus tomography (microCT), light (H&E histology), and electron (SBF-SEM) microscopy, we generate quantitative structural datasets across spatial scales. In a mouse placenta, correlative 3D X-ray histology (3D-XRH) links histological features directly to their 3D tissue context. In a human placenta, multimodal imaging integrates whole-organ microCT with correlative X-ray and electron microscopy (CXEM) to quantify the total exchange surface area, bridging organ-scale structure and ultrastructural detail. Finally, using placentas from giraffes and rhinos, we show how microCT can be used to quantify the whole organ structure of placentas from even very large mammals, quantifying metrics such as cotyledon volume distribution and blood vessel architecture. Together, these examples illustrate the power of correlative multiscale 3D imaging to resolve mammalian placental structure, bridging cellular and organ-level organisation. This integrative approach provides a unified framework for quantitative comparative placentation, linking structural diversity to physiological function
LUNG CARCINOIDS (Lung Neuroendocrine Tumors)
No full textInternational audienceAbstract This narrative review written by experts aims to provide a comprehensive synthesis of current knowledge and guidelines on lung carcinoids, emphasizing the multidimensional approach required for effective diagnosis and management. The manuscript will: i) Define and classify lung carcinoids in accordance with the latest WHO classification system, and emphasize the importance of molecular markers for precise subtyping; ii) Analyze epidemiological trends, discuss prevalence, incidence, and mortality rates, alongside key risk factors including genetic predispositions (MEN1) and precursor lesions such as diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH); iii) Investigate the etiology and carcinogenesis of lung carcinoids, including insights into the molecular hallmarks and pathways that underlie tumor development and progression; iv) Detail clinical presentations, distinguishing pulmonary symptoms from secretory syndromes (carcinoid syndrome and Cushing’s syndrome), supported by visual aids to elucidate symptom prevalence and implications; v) Present an integrated diagnostic approach, encompassing state-of-the-art imaging modalities (CT, MRI, 68Ga-SSA-PET-CT) and advanced molecular pathology techniques; vi) Outline evidence-based treatment strategies, addressing early-stage interventions, systemic therapies, locoregional therapies, and emerging modalities such as immunotherapy and agnostic approaches; vii) Explore the role of multidisciplinary management, highlighting the critical importance of tumor boards dedicated to lung carcinoids and provide a checklist of key items for comprehensive case discussion and decision-making; viii) Conclude with future perspectives, identifying gaps in current knowledge and suggest directions for research to enhance diagnosis, treatment, and overall patient quality of life
Méthodes de diagnostic de l’infection par Cryptosporidium spp. chez les ruminants: connaissances actuelles et tendances futurs
No full textInternational audienceCryptosporidiosis is a parasitic disease widely distributed worldwide and is frequently responsible for waterborne and foodborne outbreaks. Advances in molecular biology have significantly improved the understanding of Cryptosporidium transmission routes, particularly its zoonotic potential. These molecular tools now play a central role in disease surveillance in industrialised countries. Although diagnosis is still largely based on microscopic examination, molecular methods — especially PCR and sequencing — are increasingly being adopted. They provide more accurate diagnosis and allow better characterisation of the species involved, thereby contributing to improved understanding of the epidemiology and contamination pathways of cryptosporidiosis.La cryptosporidiose est une maladie parasitaire largement répandue dans le monde, fréquemment responsable d’épidémies d’origine hydrique et alimentaire. Les progrès en biologie moléculaire ont permis d’améliorer la compréhension des modes de transmission de Cryptosporidium , notamment de sa dimension zoonotique. Ces outils occupent aujourd’hui une place centrale dans la surveillance de la maladie dans les pays industrialisés. Bien que le diagnostic repose encore principalement sur l’observation microscopique, les méthodes moléculaires, en particulier la PCR et le séquençage, se développent rapidement. Elles offrent un diagnostic plus précis et permettent une meilleure caractérisation des espèces impliquées, contribuant ainsi à une meilleure compréhension de l’épidémiologie et des voies de contamination de la cryptosporidiose
High-throughput screening for tick-borne pathogens in Ixodid ticks collected through crowdsourcing in northern Sweden
No full textInternational audienceAbstract Background Ticks are expanding in the northern hemisphere. Along with them, tick-borne pathogens can be introduced into new geographical areas and cause infection and disease in animals and humans. Monitoring the expansion of tick populations is challenging and in large areas such as northern Sweden it can be beneficial to take advantage of citizen science. Therefore, people living in northern Sweden were asked to submit ticks collected from their pets or from themselves during the tick seasons of 2018 (north of river Dalälven; n = 1087) and 2019 (from the four northernmost Swedish provinces; n = 514). Ticks were identified at the species level and further analysed with a microfluidic technique to detect carried tick-borne pathogens. Forty-eight PCR assays targeting an array of tick-borne bacteria, viruses and protozoa were performed per sample in the assay. Results The most frequently detected pathogens were Rickettsia helvetica (15.6% in 2018 and 3.5% in 2019) followed by Borrelia garinii (5.9% in 2018 and 11.5% in 2019) and Borrelia afzelii (5.7% in 2018 and 1.2% in 2019). Conclusions This study provides data on tick-borne pathogens harbored by feeding ticks collected from a rather poorly investigated geographical area using a One Health perspective. Microfluidic techniques are confirmed to be an effective tool to screen large amounts of samples and to also find pathogens occurring at lower rates. This approach best supports the design of updated risk-maps and to find areas that deserve targeted tick sampling to obtain a more accurate risk assessment and achieve effective disease prevention
Environmental tracking of viral pathogens in surface waters around Paris using high-throughput PCR
No full textInternational audienceSurface waters that receive discharges from wastewater treatment plants and other sources of pollution are therefore highly susceptible to microbiological contamination. They can be contaminated by a wide variety of viruses, some of which are known to persist in the environment for extended periods. In this study, we assessed the viral contamination of the Seine and Marne rivers in the Paris area by analyzing 42 water samples collected in both winter and summer 2023. Norovirus GI and GII were quantified by RT-qPCR, and a high-throughput PCR array was used for the qualitative detection of 30 viruses, including enteric viruses, respiratory viruses, and indicators of fecal contamination. Noroviruses were detected in 10–82% of the samples tested, depending on the river and season, at concentrations ranging between 5.8 × 101 and 1.1 × 103 genome copies/L. Across the entire sampling campaign, the most prevalent human viruses detected using the PCR array were aichivirus, adenovirus, and bocavirus (74–83%), followed by enterovirus, astrovirus, norovirus, and cosavirus (12–26%). Some other viruses were sporadically detected (sapovirus, hepatitis A and E viruses, OC43, measles virus). The PCR array enables the simultaneous detection of diverse viruses in a single assay, making it a powerful tool for environmental surveillance of multiple pathogens. Its adaptability allows for the detection of a broad range of targets, delivering results within a short timeframe, typically within the same day
Qui était le Professeur François Hilaire Gilbert, directeur adjoint de l’École vétérinaire d’Alfort et membre de la Commission d’Agriculture pendant la Révolution : un vétérinaire ou un agronome ?
No full textInternational audienceFrançois-Hilaire Gilbert, veterinarian and deputy director of the École vétérinaire d’Alfort, is associated with Merino sheep. However, he was also an eminent agronomist. Why was he interested in agronomy? How did he manage this dual career as an agronomist-veterinarian or veterinarian-agronomist? To explain this, we must go back to his formative years, the travels that familiarized him with the rural world, and his years as a teacher at the École d’Alfort during the so-called “academic” period. As Daubenton's assistant, he discovered a new discipline: “rustic economics.” During the French Revolution, the government heavily involved scholars. François-Hilaire Gilbert was reincarnated as a patriot. As a member of the Commission of Agriculture and Arts, he became a leading specialist in “rural economy” and took charge of the “rural establishments of the Republic” under the Directory government. The experiments he conducted there were entirely related to agronomy, as we understand it today. He was also the first veterinarian appointed to the National Institute in the “Section of Rural Economy and Veterinary Science.” Among his many publications, veterinary writings are clearly in the minority compared to those predominantly focused on agronomy. Historical reasons exist for why veterinarians, such as François-Hilaire Gilbert, were consulted and involved in all matters related to livestock farming. At the end of the 18th century, agronomy was a discipline in its infancy, the word “agronomist” was just beginning to be used, and agronomy schools did not yet exist. Veterinarians were therefore the only legitimate experts in the agricultural world at the time, as they were trained in a school recognized by the state.Le nom de François Hilaire Gilbert, vétérinaire, directeur adjoint de l’École vétérinaire d’Alfort, est associé au mouton mérinos. Or il a aussi été un agronome éminent. Pourquoi s’est-il intéressé à l’agronomie ? Comment a-t-i l mené cet te double carrière d’éminent agronome ou de vétérinaire-agronome ? Pour l’expliquer, on remontera à ses années de formation, à ses voyages qui l’ont familiarisé avec le monde rural, à ses années d’enseignant à l’École d’Alfort, durant la période dite « académique ». Assistant de Daubenton, il découvre une discipline nouvelle : « l’économie rustique ». Sous la Révolution, le gouvernement implique fortement les savants. François-Hilaire Gilbert se réincarne en citoyen républicain. Membre de la Commission de l’Agriculture et des Arts, il devient un spécialiste incontournable de « l’économie rurale » et prend la direction des « établissements ruraux de la République » sous le Directoire. Les expériences qu’il y fait mener relèvent tout à fait de l’agronomie, dans le sens que nous lui donnons aujourd’hui. Il est par ailleurs le premier vétérinaire nommé à l’Institut nation al dans la « Section d’économie rurale et art vétérinaire » . Parmi ses nombreuses publications, les écrits vétérinaires sont nettement minoritaires par rapport à ceux à dominante agronomique. Si des vétérinaires comme François-Hilaire Gilbert sont consultés et interviennent sur toutes les questions relatives à l’élevage, c’est pour des raisons historiques. En cette fin du XVIIIe siècle, l’agronomie est une discipline en gestation, le mot « agronome » commence juste à être employé, les écoles d’agronomie n’existent pas encore. Les vétérinaires sont donc, à l’époque, les seuls référents du monde agricole qui soient légitimes, car formés dans une école reconnue par l’État
Impact of Lactobacillus johnsonii CNCM I-4884 on canine giardiasis: a probiotic-based approach
No full textInternational audienceThis study reports a new therapeutic approach for canine giardiasis, the most common intestinal protozoan infection caused by Giardia intestinalis. It is based on the use of the probiotic strain Lactobacillus johnsonii CNCM I-4884 and, in particular, its bile salt hydrolase enzymatic activities. Clinical trials in dogs demonstrated that daily administration of L. johnsonii CNCM I-4884 significantly reduced Giardia cyst shedding after 14 days. These results highlight the potential of this probiotic as a promising alternative to antimicrobials, such as nitroimidazoles or benzimidazoles, for the treatment of giardiasis in dogs. Moreover, they provide a novel approach for the veterinary industry to develop innovative products targeting this parasite. In addition to its direct anti-Giardia effect, L. johnsonii CNCM I-4884 may also act as an adjuvant therapy, supporting intestinal homeostasis, enhancing host defense mechanisms, and promoting recovery of gut balance during or after antiparasitic treatments. This dual role suggests that the strain could be considered not only as a complementary therapy but, in specific cases, as a potential stand-alone probiotic treatment for canine giardiasis
Application of non-destructive DNA extraction for the molecular and morphological identification of tick species and their pathogens
No full textInternational audienceTick-borne diseases remain a major concern in both human and animal health in most biogeographical regions. Since certain tick-borne pathogens are transmitted by specific tick species, tick identification through morphological and biomolecular examination of the species is highly recommended for investigation of tick-borne diseases. In this study, we assessed a non-destructive DNA protocol for identifying tick species and screening of pathogens and evaluate the effects of this protocol on the tick body, using geometric morphometry (based on coxa 1). Overall, 80 Ixodes spp. specimens (I. ricinus, I. hexagonus, and I. acuminatus) conserved in alcohol for more than 15 years were tested here, including all stages (male, female, nymph and larva). Molecular investigation using 16S rRNA enabled 92% of ticks to be assigned to a species. The microfluidic chip demonstrates the presence of Bartonella sp. (13%), Rickettsia helvetica (63%) and Hepatozoon spp. (13%) in tested engorged females. Comparison of the coxa 1 shape before and after extraction showed no changes in morphology. We demonstrated that DNA can be extracted from old specimens of hard ticks using non-destructive methods, allowing for molecular identification of ticks and pathogens without altering their morphology. As a result, this technique makes it possible to preserve specimens from laboratory or museum collections. Additionally, non-destructive DNA extraction could be useful in medical entomology for monitoring arrivals of alien species and emergence of associated tick-borne diseases affecting humans, domestic animals, or wildlife