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Co-inoculation of broilers by Campylobacter and Salmonella : effect on colonization, cecal microbiota, and serum metabolome
No full textInternational audienceABSTRACT Campylobacteriosis and salmonellosis are the leading bacterial zoonoses in Europe, with poultry meat being the primary source of human contamination. Although both Campylobacter and Salmonella bacteria can coexist asymptomatically in chickens, their reciprocal impact remains underexplored. An in vitro study showed that Campylobacter jejuni survival was positively affected by the presence of Salmonella , but no data are available on this interaction in the animal gut. In this study, an in vivo investigation was carried out to explore the dynamics between Campylobacter and Salmonella colonization in chickens. The results revealed that both Salmonella and Campylobacter maintained significantly higher levels of colonization in the ceca throughout the experiment when co-inoculated compared to when inoculated alone. Additionally, changes in the microbiota were associated with each pathogen inoculated alone, but the simultaneous presence of Campylobacter and Salmonella induced specific modulations that could possibly explain this phenomenon. Significant differences were found in the serum metabolome of the contaminated groups, and partial least squares discriminant analysis models enabled the discrimination of contaminated animals from controls using these metabolic signals. Furthermore, possible links between variations in the microbiota and variations in the metabolome were identified. IMPORTANCE This study demonstrates a synergistic effect between Salmonella and Campylobacter jejuni in the gut during co-infection in chickens, leading to an increased presence of both pathogens, as well as unique microbiota and metabolome changes. These findings underscore the importance of considering co-infection in poultry control measures and highlight the complex interplay between pathogens, microbiota, and metabolism
Vaccination against H5 HP avian influenza virus leads to persistent immune response in wild king penguins
No full textInternational audienceSince 2021, the panzootic nature of high pathogenicity avian influenza (HPAI) represents an increasing threat to wild vertebrate populations. In this context, recent vaccines developed for poultry could provide tools for the conservation of wild endangered birds populations. The king penguin ( Aptenodytes patagonicus ), a long-lived seabird breeding in dense colonies with an extended chick-rearing period, has been identified as a possible surrogate species for a vaccination trial in a sub-Antarctic natural setting. Here we investigate the immune response of king penguin chicks to a self-amplifying mRNA vaccine against a H5 HPAI clade 2.3.4.4b protein. The cohort entails thirty vaccinated chicks (primo- and boost-injections), and 20 unvaccinated controls. Along 250 days of monitoring, the vaccinated chicks show a high and persistent immune response, granting a strong sero-neutralisation capacity against the virus, up to fledging. No adverse effects are observed. Screening for antibodies against unspecific avian influenza viruses suggests that no natural infection has occurred over the entire trial. The emergence of HPAI in the Southern Indian Ocean in October 2024 highlights the timeliness of such experimental tests. Our results thus show the vaccine could provide a potentially powerful tool for mitigation of avian flu outbreaks in the wild
Revealing cryptic lineages: genetic structure and conservation units in the Eurasian Stone-curlew (Burhinus oedicnemus)
No full textInternational audienc
Impact of Tidal Forcing on Surface Particle Transport Properties: Insights From Twin Ocean Simulations
No full textInternational audienceUnderstanding the transport pathways of floating material at the ocean surface is important to improve our knowledge on surface circulation and assessing its environmental impacts. Numerical experiments through Lagrangian particle simulations are widely used to investigate the dispersion of floating material, typically relying on velocity fields from ocean circulation models. However, the contribution of different ocean dynamics (at different temporal and spatial scales) to the net Lagrangian transport remains unclear. Here we focus on tidal forcing, only included in recent ocean models, to explore its effect on particle dispersion at the ocean surface. By comparing a twin simulation with and without tidal forcing, we conclude that tide‐induced dynamics play an important role in horizontal Lagrangian pathways. We focus on the Azores Islands region and find that surface particles travel a longer cumulative distance and a lower total distance with than without tidal forcing. Additionally, tidal forcing leads to higher variability in surface particle accumulation patterns. The differences found in the surface particle accumulation patterns can be greater than 40%. These findings have important implications for virtual particle simulations, suggesting that considering tidal currents alone may not capture the full range of tide‐induced effects. A deeper understanding of the underlying dynamics is essential for accurately analyzing transport properties. Our outcomes can already help improve Lagrangian simulations made to understand the connectivity of marine species and for marine pollution applications, for example, ocean clean‐up strategies for plastics or oil spills, in the Azores Islands and regions with similar dynamics
Qui sont les « agents de terrain » des agences de l'eau ?: Un métier à l'épreuve des réformes environnementales
No full textInternational audienceIn this article, we explore a “fuzzy” job, that of intervention officer for the Water Agencies. Real Street-level bureaucrats, these agents do not merely process subsidy applications. Increasingly, as water policies become more ecological and subject to neo-managerial reforms, they actively contribute to the emergence of projects and to raising their ambition level. As such, they have a policy-making role, helping to redefine priority actions, but above all developing strategies to encourage project developers to implement prioritized actions, using the levers of economicization, rationalization and empowerment.Dans cet article, nous explorons un métier « flou », celui de chargé d'intervention des agences de l'eau. Véritable Street-level bureaucrat, le chargé d'intervention ne se contente pas d'instruire les dossiers d'aide, mais contribue de plus en plus, au fil de l'écologisation des politiques de l'eau et des réformes néo-managériales, à faire émerger les projets ou les faire monter en ambition. À ce titre, il a un Policy making role en contribuant à redéfinir les actions prioritaires, mais surtout en développant des stratégies pour inciter les maîtres d'ouvrage à mettre en oeuvre les actions priorisées, en utilisant les leviers de l'économicisation, de la rationalisation, et de la responsabilisation
Quelle vision de la production porcine par les apprenants en formations agricoles dans le Massif central ?
No full textInternational audienceDéfi du renouvellement des éleveurs très prononcé en porc dans le Massif centralApprenants de ce territoire herbager sont familiarisés avec l’élevage herbivore mais développent peu de projets porcinsOr…plusieurs rôles majeurs du porc dans le Massif : maintien d’abattoirs, de salaisonneries, de traditions et savoir-faire culinaires…<br /
Near-complete genome sequences of a rice necrosis mosaic virus isolate infecting rice in Argentina
No full textInternational audienceABSTRACT While rice necrosis mosaic virus (RNMV) has only been described in Asia, we identified this virus on a rice plant from Argentina using a viral metagenomic approach. We further confirmed this result by RT-PCR and small-RNA Illumina sequencing to obtain the near-complete genome and to confirm actual infection by RNMV
Analyzing temporal dependence between extreme events using point processes
No full textExtreme meteorological events often occur in complex temporal configurations, where the impacts of one hazard may depend on the prior occurrence of others. Characterising such temporal dependencies is essential for understanding compound climate risks, yet remains challenging due to the discrete, heterogeneous, and clustered nature of extreme events. In this study, we apply temporal point process methods to characterise dependencies among extreme meteorological events occurring within appropriately defined spatial regions across Europe, focusing exclusively on their temporal structure.We introduce an event-based framework in which extreme events are represented as marked temporal point processes, with marks describing key characteristics such as intensity or duration. Global first-and second-order temporal statistics are used to quantify clustering, co-occurrence, and directional dependencies between different types of extremes. In particular, we rely on directional cross-K functions to assess whether the occurrence of one type of extreme event systematically modifies the short-term probability of subsequent events of another type.Two complementary applications illustrate different facets of compound event analysis. First, we demonstrate the relevance of the framework for preconditioned compound events through a temporal analysis of wildfire-related meteorological extremes.Second, we examine temporal dependence between extreme precipitation, extreme wind, and extreme atmospheric instability across all European NUTS-2 regions.Building on these second-order statistics, we develop formal tests of temporal independence to assess the significance of observed directional interactions between different types of extreme events. Overall, this temporal point process framework provides a rigorous and interpretable approach to the analysis of compound and preconditioned climate extremes, with direct applications to climate risk assessment and early-warning systems
Impact of triazoles on ovarian cells of patients and link to groundwater and soil
No full textPlant protection products used in agriculture contain molecules specifically designed to be toxic to target organisms. However, their use can also have unintended effects, posing potential risks to ecosystems and non-target organisms, including humans. Research has deepened our understanding of the links between exposure to these substances and the effects observed in the environment. In particular, studies have highlighted how even low levels of exposure can cause chronic effects on non-target organisms and disrupt ecosystems. These findings underscore the importance of quantifying and characterising these exposures in order to better assess their potential impacts on human health and the environment.International audiencePolycystic ovary syndrome (PCOS), often associated with obesity, is the main reproductive disorder in women of childbearing age. Two fungicides, Tebuconazole (Tb) and Epoxiconazole (Epox), are present in soils and groundwater in the Centre Val de Loire region. We show that Epox and Tb reduce steroid synthesis by human ovarian cells (hCG), probably via the nuclear receptor, AhR. Moreover, Tb is more cytotoxic than Epox on hCG. Finally, we found that Tb and Epox more strongly altered the ovarian cells of PCOS and/or obese patients, suggesting that women with certain fertility and/or metabolic disorders are more sensitive to triazole exposure