Portail des publications scientifiques de VetAgro Sup
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Food processing and sustainability: Exploring new multidisciplinary perspectives
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Controverses cliniques, diagnostiques et thérapeutiques sur les piroplasmoses équines
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Infectious potential and circulation of SARS-CoV-2 in wild rats
No full textInternational audienceSince the beginning of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, a wide range of animal species (pets, mink…) have been naturally infected with this betacoronavirus. The emergence of new variants has increased the ability of SARS-CoV-2 to infect species that were not susceptible to the “original” SARS-CoV-2, such as mice and rats. This work attempted to evaluate the role of urban rats in the SARS-CoV-2 transmission by combining surveillance studies of rat populations in urban environments, in vivo experimental inoculation of SARS-CoV-2 and comparative viral-receptor interaction in silico analyses. We studied the circulation of SARS-CoV-2 in wild Rattus norvegicus (n = 401) captured in urban areas and sewage systems of several French cities. Except for 3 inconclusive samples (2/75 from Bordeaux and 1/261 from Lyon) none of the 353 sera tested showed anti-SARS-CoV-2 antibodies by microsphere immunoassay. However, the 3 inconclusive sera samples were negative by virus neutralisation assay. No SARS-CoV-2 viral RNA was detected in all lungs collected from the 401 captured urban brown rats. In complement, four rat groups (two wild-type colonies, Rattus norvegicus and Rattus rattus , and two laboratory strains, Sprague-Dawley and Wistar) were inoculated with the SARS-CoV-2 Omicron BA.5. At 4 days post-inoculation, no infectious viral particles were detected in the lungs and upper respiratory tract (URT) while viral RNA was detected at a low level only in the URT of all groups. In addition, seroconversion was observed 14 days after inoculation in the four groups. By molecular modelling, the Omicron BA.5 receptor binding domain (RBD) had lower affinities for Rattus norvegicus and Rattus rattus ACE2 than Homo sapiens ACE2. Based on these results the SARS-CoV-2 Omicron BA.5 was unable to infect laboratory and wild type rats. In addition, Rattus norvegicus collected for this study in different areas of France were not infected with SARS-CoV-2
Quantitative risk assessment for the introduction of bluetongue virus into mainland Europe by long‐distance wind dispersal of Culicoides spp.: A case study from Sardinia
No full textInternational audienceEurope faces regular introductions and reintroductions of bluetongue virus (BTV) serotypes, most recently exemplified by the incursion of serotype 3 in the Netherlands. Although the long‐distance wind dispersal of the disease vector, Culicoides spp., is recognized as a virus introduction pathway, it remains understudied in risk assessments. A Quantitative Risk Assessment framework was developed to estimate the risk of BTV‐3 incursion into mainland Europe from Sardinia, where the virus has been present since 2018. We used an atmospheric transport model (HYbrid Single‐Particle Lagrangian Integrated Trajectory) to infer the probability of airborne dispersion of the insect vector. Epidemiological disease parameters quantified the virus prevalence in vector population in Sardinia and its potential first transmission after introduction in a new area. When assuming a 24h maximal flight duration, the risk of BTV introduction from Sardinia is limited to the Mediterranean Basin, mainly affecting the southwestern area of the Italian Peninsula, Sicily, Malta, and Corsica. The risk extends to the northern and central parts of Italy, Balearic archipelago, and mainland France and Spain, mostly when maximal flight duration is longer than 24h. Additional knowledge on vector flight conditions and Obsoletus complex‐specific parameters could improve the robustness of the model. Providing both spatial and temporal insights into BTV introduction risks, our framework is a key tool to guide global surveillance and preparedness against epizootics
Impact of ultrasonication, ozonation, and their combination on the preservation of novel clean-label functional drink of strawberry-cantaloupe incorporated with Spirulina platensis and orange peel extracts
No full textInternational audienceConsumer demand for sustainable, nutrient-rich, and clean-label beverages is rapidly increasing, which is driving the need for innovative preservation techniques for such sensitive beverages in place of conventional chemical preservatives and thermal treatments, which have several drawbacks. These advanced methods need to be effective in maintaining quality, retaining bioactivity, ensuring safety, and extending the shelf life of these novel sensitive beverages. This study focused on the sustainable non-thermal preservation of a novel clean-label functional drink formulated from strawberry and cantaloupe juice, incorporated with Spirulina platensis and orange peel extracts. The drink was subjected to conventional pasteurization (90 degrees C for 1 min), ultrasound treatment (300 W power, 25 kHz frequency, 10 min at 25 degrees C), ozone treatment (30 mg/L concentration, 1 L/min flow rate, 10 min at 25 degrees C), and a combined ultrasound and ozone treatment, applying the same parameters for 5 min each. The treated drink samples were stored at 4 degrees C for two months, and various analyses were conducted over a fifteen-day period to assess preservation outcomes. The best results, in terms of maintaining quality, retaining bioactivity, ensuring safety, and enhancing shelf life, were achieved with the combined treatment of ultrasonication and ozonation. This research highlights the importance of synergistic non-thermal technologies over single treatments in the preservation of beverages. Additionally, the presence of antimicrobial and antioxidant compounds from the algal and plant extracts in the drink formulation also contributed to its extended shelf life. These findings demonstrate the potential of sustainable and environmental friendly non-thermal technologies for preserving functional beverages without compromising their functional attributes. The findings pave the way for future research and industrial-scale adoption of sustainable preservation methods, contributing to a healthier and more sustainable food system
Nonliving respiration: Another breath in the soil?
No full textInternational audienceThe present study challenges the traditional view that the respiration of organic carbon to CO 2 is an exclusively intracellular process, revealing that organic compound respiration can occur spontaneously in an extracellular context in soils. Using 1 H nuclear magnetic resonance spectroscopy to analyze the dynamics of the sterile soil exometabolomes alongside C-CO 2 flux analyses and sterile soil fuel cells, we show that soil catalysts facilitate a diverse array of substrate-driven reactions, leading to the complete oxidation of organic compounds to CO 2 with O 2 consumption. Our results indicate that soil particles are capable of transferring electrons from substrates to the final acceptor, thereby sustaining metabolism-like processes independently of living cells. Notably, some soil catalysts and induced respiration remain stable for more than 6 years. These findings support the coexistence of cellular and noncellular metabolic pathways in soil respiration
The time of infection matters: seasonal interplay between host and pathogen drives epidemic dynamics
No full textInternational audienceHost and pathogen dynamics are driven by seasonal variation, leading to complex epidemic patterns which are not well understood. Here, we linked demography and epidemiology in a single framework to reach a mechanistic understanding of disease dynamics in natural populations characterized by seasonality. We applied this approach to depict the interplay between a host, the wild boar, and a viral disease, African swine fever. This virus spreads in wild boar by direct‐contact among living individuals or though contacts with infected carcasses. In this system, both host and pathogen show seasonal patterns: survival and reproduction probabilities vary across the year in the wild boar, and virus persistence in the environment is affected by temperature which influences the speed of carcasses degradation. Using a stochastic individual‐based model, we showed that virus invasion success strongly varies according to the time of introduction due to the seasonal specific interaction between the virus and host. Furthermore, the shape of the following epidemic varies across seasons, with variation in speed and magnitude of the outbreak. Consequently, the host population response was also season‐specific, both regarding the speed of the decline and the change in population structure. Overall, our study highlights the inextricable connections between host, pathogen and the environmental dynamics, and the importance to consider each component to understand disease dynamics
Validation d’une méthode ELISA de dosage de la progestérone plasmatique bovine, dans un objectif d’étalonnage d’un biocapteur électronique embarqué
No full textInternational audienceLa démarche métrologique suivie pour développer une méthode d’analyse dans un laboratoire de recherche doit permettre de démontrer l’adéquation de ses performances au besoin analytique. L’objectif de ce travail a consisté à valider dans notre laboratoire une méthode d’analyse ELISA (Enzyme-Linked Immuno Sorbent Assay) de la progestérone plasmatique bovine, en qualité de méthode de référence. Les valeurs mesurées avec cette méthode d’analyse serviront de référence dans notre laboratoire pour étalonner un biocapteur électrochimique embarqué, développé dans le cadre du projet SmartRepro pour détecter les ovulations chez les vaches et permettre aux éleveurs de savoir à quel moment pratiquer l’insémination artificielle. Cette détection sera basée sur le prélèvement de fluides interstitiels et le monitoring des hormones impliquées dans la régulation du cycle ovarien et le déclenchement de l’ovulation, dont la progestérone. La démarche de validation de la méthode d’analyse pour ce projet a consisté à suivre deux étapes métrologiques : 1/ Vérifier sa conformité au regard de performances préconisées par la Food and Drug Administration (FDA) qui propose des limites d’acceptabilité de ± 30 % pour son exactitude, et 2/ Valider les performances de la méthode d’analyse au regard de l’objectif scientifique du projet SmartRepro. Cette démarche a permis d’obtenir le modèle de l’incertitude de mesure (IM) élargie suivant : U(Y) = 0,2004Y0.9684. Il a été démontré, en utilisant l’IM et le seuil de discrimination (SD) de la méthode, qu’elle était capable de décrire fidèlement l’évolution du taux de progestérone plasmatique. C’est cette capacité qui sera évaluée dans un 2e temps pour le biocapteur électronique embarqué, en prenant comme référence les valeurs obtenues par la méthode de dosage de la progestérone présentée dans cet article. De plus, les informations métrologiques obtenues permettront d’évaluer la capacité de cette méthode de référence à être utilisée dans de futurs projets de recherche
Post-graduate training honeybee health and medicine for veterinarians in France
No full textInternational audienceSince 2005, the National Veterinary Schools of Nantes and Alfort have proposed a post-graduate training in Honeybee Health. The “Honeybee Health and Medicine” program was created to develop diagnostic skills and provide expertise to veterinarians. The certification aims to provide veterinarians the following skills: Observation and interpretation of colony disorders; Diagnosis of Honey Bee colony diseases and health troubles and collecting relevant samples; Assessment of the human, material and wildlife environment of a beekeeping farm; Prevention of the spreading of regulated diseases by implementing and supervising control measures; Prescription of appropriate veterinary drugs; Understanding relevant regulation; Acting as an official vet in the beekeeping field. The training includes 200 hours of theoretical and practical training: Honey Bee biology and colony life; Practical handling, Sampling, and diagnosis; Health disorders and troubles; Regulations; Implementation of Honeybee colonies health audits (and sanitary audits of the beekeeping practices and technics). To date, 289 veterinarians have been graduated. Their diversity and nationwide distribution have created a unique Honeybee health network. The Ministry of Agriculture officially recognized this program in 2014. The graduated veterinarians (working in private practice, administration, diagnostic laboratories, and pharmaceutical industry) carry out key missions: Protecting and treating Honeybee colonies; Implementation of studies, Field surveys, and epidemiological surveillance; Self guarding food safety and public health; Protecting the environment; Advancing research and training. Since 2024, the diploma has been certified by all four French National Veterinary Schools. To improve accessibility and recognition, a submission will be made to the “National Authority for Regulating and Financing Vocational Training” for registration in the “specific repertory”
