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[hal-05630782] Zoonotic Cryptosporidium and Giardia infections in pigeons (Columba spp.) at a wildlife hospital in France: Occurrence and molecular identification
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ano.nymous@ccsd.cnrs.fr.invalid (Anaïs Devulder) 22 May 2026
https://hal.science/hal-05630782v1
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[hal-05578664] Lower prevalence of Lyme disease pathogens in mixed deciduous – coniferous forests
A growing number of studies demonstrate the consequences of biodiversity loss on the increased prevalence of vector-borne diseases such as Lyme borreliosis. Given that vertebrate host species differ in their competence for pathogen transmission, it has been hypothesized that greater host diversity, which is more likely to occur in mixed forests, would reduce pathogen prevalence in ticks through a dilution effect. However, empirical evidence remains mixed, particularly in Europe, and recent studies suggest that habitat characteristics and vegetation structure may also play a key role in the risk of tick-borne disease. We sampled ticks along gradients of forest compositional diversity in a network of seven sites in Europe to assess the combined effect of tree and understorey plant diversity on ticks and associated pathogens. We found that several forest habitat characteristics were associated with variations in Ixodes ricinus densities and infection rates. The proportion of I. ricinus nymphs infected by Borrelia was lower in mixed than in pure forests. The prevalence of Borrelia and Rickettsia respectively increased and decreased with the richness of understorey plants. Ixodes ricinus larvae density increased with the proportion of plants palatable to roe deer (Capreolus capreolus). Our results suggest that forest diversity, at both tree and understorey levels, influences ticks and associated pathogens through several direct and potential indirect mechanisms such as effects on vertebrate hosts, particularly herbivores. Habitat and resource diversification of vertebrate hosts provides a useful theoretical framework to guide forest management toward reducing human health risks.
ano.nymous@ccsd.cnrs.fr.invalid (Audrey Bourdin) 03 Apr 2026
https://hal.inrae.fr/hal-05578664v1
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[hal-05636707] Therapeutic and Preventive Methods for Controlling Cryptosporidiosis in Ruminants
Cryptosporidiosis is a parasitic disease caused by the intestinal protozoa of the genus Cryptosporidium . Curative therapy in animals exhibiting clinical diarrhoea is based on halofuginone lactate or paromomycin sulfate. Preventive measures, which should be prioritised, encompass both a sanitary component — focused on strict hygiene management and adequate colostrum administration — and a medical component involving the use of halofuginone lactate and/or a recently introduced vaccine for passive immunisation of calves. An integrated approach combining both sanitary and medical preventive strategies is strongly recommended.
ano.nymous@ccsd.cnrs.fr.invalid (Faten Bouaicha) 28 May 2026
https://hal.science/hal-05636707v1
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[hal-05630754] Cryptosporidium and Giardia in Côte d’Ivoire: a review within a One Health concept
Background: Cryptosporidium and Giardia are common intestinal protozoa that infect humans, as well as domestic and wild animals. They rank among the most prevalent waterborne parasites and are particularly widespread in developing countries. The advent of molecular diagnostic tools has played a major role in improving our understanding of the transmission of Cryptosporidium spp. and Giardia duodenalis. A thorough understanding of their molecular diversity, geographical distribution, and the environmental and climatic factors that influence their prevalence is essential for effective control in vulnerable populations. However, knowledge about their epidemiology in Africa remains limited. Both parasites negatively impact child growth and development, particularly when affected individuals suffer from aggravating factors, such as malnutrition and HIV. Aim: This review highlights research conducted in Côte d’Ivoire involving humans, animals, and the environment, and emphasizes the importance of the One Health framework. Methods: Relevant publications from March 1990 to December 2024 were sourced from PubMed and ResearchGate. Results: Out of the 26 studies identified, only 9 employed molecular tools and 17 used microscopy tools to detect G. duodenalis and Cryptosporidium spp. Findings confirmed the presence of the parasite in humans, livestock (including cattle, sheep, and camels), and environmental samples (water and soil). The prevalence and genetic diversity of G. duodenalis isolates varied by region and age group in both humans and animals. Conclusions: This study shows that Cryptosporidium and Giardia are widespread in humans and animals in Côte d’Ivoire, with both anthroponotic and zoonotic transmission cycles.
ano.nymous@ccsd.cnrs.fr.invalid (Karim Tuo) 22 May 2026
https://hal.science/hal-05630754v1
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[hal-05630936] Probiotiques de nouvelles génération contre les parasitoses intestinales : une stratégie One Health prometteuse
Les probiotiques suscitent un intérêt croissant en tant qu’approches innovantes, alternatives ou complémentaires, pour la prévention et la prise en charge des infections intestinales, en réponse aux limites et aux échecs thérapeutiques des traitements antiparasitaires conventionnels, notamment dans le cas de la giardiose [1], parasitose intestinale fréquente chez l’humain et l’animal [1-2]. Dans ce contexte, certaines souches bactériennes présentent des propriétés antimicrobiennes spécifiques, susceptibles de contribuer à la lutte contre les infections intestinales, sont activement recherchées. La souche probiotique Lactobacillus johnsonii CNCM I-4884 a ainsi été identifiée par notre équipe pour son activité antagoniste contre Giardia intestinalis, protozoaire responsable de la giardiose. L’activité antiparasitaire de cette souche repose notamment sur ses hydrolases des sels biliaires (BSH). Ces enzymes sont capables de déconjuguer les acides biliaires, générant ainsi des métabolites (acides biliaires déconjuqués), dont certains présentent une toxicité pour le parasite. Afin d’optimiser le potentiel de ce probiotique, cette souche a été soumise à une pression de sélection visant à augmenter son activité BSH, conduisant à l’obtention de dérivés présentant une efficacité accrue in vitro et in vivo contre les formes trophozoïtes du parasite responsables des signes cliniques. Ces résultats confirment que l’ingénierie génétique de bactéries probiotiques, visant à renforcer certaines activités enzymatiques, constitue une piste prometteuse pour le développement de stratégies alternatives ou complémentaires aux traitements antiparasitaires conventionnels. Dans le cadre d’une approche « One Health », le recours à des probiotiques optimisés pourrait contribuer à améliorer la prise en charge des infections intestinales tout en limitant l’émergence de résistances aux traitements antimicrobiens chimiques, aussi bien chez l’humain que chez l’animal. References: [1]Allain T.; Chaouch S.; Thomas M.; Travers M.-A.; Valle I.; Langella P.; Grellier P.; Polack B.; Florent I.; Bermúdez-Humarán L.G. Bile Salt Hydrolase Activities: A Novel Target to Screen Anti-Giardia Lactobacilli? Front. Microbiol., 2018. 9, 89. https://doi.org/10.3389/fmicb.2018.00089 [2]Boucard A.-S.; Florent I.; Polack B.; Langella P.; Bermúdez-Humarán L.G. Genome Sequence and Assessment of Safety and Potential Probiotic Traits of Lactobacillus johnsonii CNCM I-4884. Microorganisms, 2022. 10(2), 273. https://doi.org/10.3390/microorganisms10020273
ano.nymous@ccsd.cnrs.fr.invalid (Damien Oliveira) 22 May 2026
https://hal.science/hal-05630936v1
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[hal-05597815] Phenology of questing Ixodes frontalis nymphs reveals a late-winter to early-spring activity peak
Although Ixodes frontalis is widespread across Europe, including urban and peri‑urban habitats, several aspects of its biology remain undescribed. One such aspect is the population dynamics of its nymphal stage, which has so far been reported from limited sample sizes, preventing the identification of its peak abundance. To fill this knowledge gap, we conducted a year-long monthly survey at four locations in France representing three different “distinct climates”. The sampling protocol - based on the flagging method performed under bamboo bushes - was designed to maximize the likelihood of capturing the nymphal stage. Based on the 400 nymphs collected during this survey, a clear peak of I. frontalis nymphs was observed around March (February to April) across all four sites, with an additional peak in August at one site. The population dynamics of the larval stage—based on semi-quantitative counts—showed the same previously described pattern, with a peak in late autumn. Twenty adults (11 females and 9 males) were also collected from March to December, but these data did not allow a clear identification of a peak abundance. Because several bird species—such as blackbirds, song thrushes, European robins, and Eurasian blackcaps—serve as feeding hosts for both I. ricinus and I. frontalis, and are also reservoirs for pathogens transmitted by these ticks, the implications of our findings for the eco-epidemiology of tick-borne diseases are discussed
ano.nymous@ccsd.cnrs.fr.invalid (Olivier Plantard) 21 Apr 2026
https://hal.inrae.fr/hal-05597815v1
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[hal-05618701] Consultations in general practice related to a tick bite episode in mainland France in 2023–2024
Abstract Background The emergence and spread of TBDs present major challenges. Exposure to tick bites in mainland France is mainly documented through local studies or citizen science projects. According to the 2024 French national survey, about 15% bitten individuals consult a healthcare professional. National-level data from general practice are needed to better describe tick bite epidemiology. Main objective To estimate the incidence of patients consulting general practitioners (GPs) for a tick bite and to describe their characteristics, their management and the context of the bite. Method We conducted a study using the French Sentinelles network, a national surveillance system that collects data from a sample of GPs. From May 2023 to April 2024, an indicator ‘Consultations with a tick bite’ was added to the routine data collection, in addition to the ongoing Lyme borreliosis surveillance. National and regional incidences were estimated using a hierarchical Bayesian model incorporating spatial and temporal dependencies to account for data sparsity. A tick collection was also carried out in order to identify the ticks and analyse the pathogens they might transmit. Results A total of 179 GPs participated and reported 483 consultations for a tick bite episode. The estimated national incidence was 324 cases per 100,000 population (95% CI [290; 369]) over the study period, peaking in May-June 2023. Incidence was highest in the southwestern and northeastern France. Children represented one quarter of cases and nearly half of patients consulted in general practice without clinical symptoms. Of the 86 ticks analysed, 24% tested positive for at least one of the pathogens tested. Conclusion These findings provide new insights into the epidemiology of tick bites in France and contribute to assessing population exposure to ticks, informing future prevention and public health strategies.
ano.nymous@ccsd.cnrs.fr.invalid (Camille Bonnet) 11 May 2026
https://hal.science/hal-05618701v1
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[hal-05630920] Giardia duodenalis en Algérie : enjeux zoonotiques et implications pour la santé publique dans une approche « One Health »
Giardia duodenalis est un protozoaire parasite qui infecte principalement l’intestin grêle de nombreux mammifères, y compris l’être humain. Il s’agit d’un complexe d’espèces composé de plusieurs génotypes appelés assemblages, classés de A à H. Parmi eux, les assemblages A et B sont considérés comme les plus zoonotiques, c’est-à-dire qu’ils peuvent être transmis entre les animaux et l’homme et représentent donc un risque important pour la santé publique. Malgré son importance sanitaire, les connaissances sur la présence et les caractéristiques génétiques de ce parasite en Algérie restent limitées. Le manque de données épidémiologiques rend difficile l’évaluation précise de son impact sur la santé humaine et animale, ainsi que l’estimation de son potentiel zoonotique. Cette revue a pour objectif de synthétiser les travaux scientifiques réalisés en Algérie concernant la présence de G. duodenalis chez l’homme, les animaux et dans l’environnement, en adoptant une approche « One Health ». Cette approche reconnaît l’interconnexion entre la santé humaine, la santé animale et l’état de l’environnement. Pour cela, les bases de données PubMed et ResearchGate ont été consultées afin d’identifier les publications traitant de G. duodenalis en Algérie entre janvier 2000 et mars 2026. Au total, 18 publications pertinentes ont été identifiées. Cependant, seulement cinq études ont utilisé des outils de biologie moléculaire pour caractériser génétiquement les isolats de G. duodenalis. Les résultats disponibles indiquent la présence du parasite chez l’être humain, chez plusieurs espèces de bétail, notamment les bovins, les ovins et les dromadaires, ainsi que dans l’environnement, à travers des échantillons d’eau et de sol. Les taux de prévalence et la diversité génétique des isolats varient selon les régions étudiées et selon les groupes d’âge, tant chez les humains que chez les animaux. L’assemblage A a été fréquemment identifié chez les humains et chez les animaux, ce qui suggère l’existence possible d’une transmission zoonotique. Néanmoins, les données restent encore insuffisantes pour comprendre précisément les voies de transmission du parasite en Algérie. Des recherches supplémentaires sont donc nécessaires afin de mieux comprendre la dynamique de transmission, le potentiel zoonotique et les conséquences de G. duodenalis sur la santé publique et le bien-être animal. Une collaboration étroite entre les professionnels de la santé est essentielle dans le cadre de l’approche « One Health ».
ano.nymous@ccsd.cnrs.fr.invalid (Myriam Thomas) 22 May 2026
https://hal.science/hal-05630920v1
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[hal-05634970] 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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ano.nymous@ccsd.cnrs.fr.invalid (Julie Rouzet) 27 May 2026
https://hal.science/hal-05634970v1
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[hal-05627134] Analyse épidémiologique, clinique et moléculaire des hémosporidioses chez des rapaces et corvidés accueillis dans un centre de soins d’Ile de France
L’impact des infections par les hémosporidies chez les oiseaux accueillis en centres de soins demeure largement méconnu. Cette étude a pour objectif la détermination de la prévalence et les facteurs de risque associés à l’admission de rapaces et de corvidés infectés dans un centre de soins de la région parisienne. En évaluant leurs chances de rétablissement et de relâcher, ainsi que les risques de transmission aux autres oiseaux hospitalisés, ce travail permet de proposer des mesures sanitaires adaptées aux structures de réhabilitation de la faune sauvage. Des prélèvements sanguins ont été réalisés sur 37 rapaces appartenant à 6 espèces et 150 corvidés issus de 4 espèces lors de leur arrivée à l’hôpital de la faune sauvage de l’École nationale vétérinaire d’Alfort (CHUV-FS, EnvA). L’identification des hémosporidies et l’estimation de la parasitémie ont été effectuées par l’analyse de frottis sanguins. Par la suite, les prélèvements positifs ont été analysés par PCR et séquençage afin d’assurer une identification moléculaire précise des parasites. Les analyses ont confirmé la présence des genres Haemoproteus, Leucocytozoon et Plasmodium. Les résultats statistiques ont mis en évidence une association significative entre l’âge des individus et l’infection par Plasmodium sp. Ce dernier s’est révélé prédominant chez les corvidés et plus fréquemment impliqué dans les cas de co-infestations, tandis que le genre Leucocytozoon semble plus prévalent chez les rapaces. Enfin, l’étude souligne qu’aucun impact significatif de ces infections n’a été observé sur le succès final du relâcher des oiseaux.
ano.nymous@ccsd.cnrs.fr.invalid (Veronica Risco-Castillo) 20 May 2026
https://hal.science/hal-05627134v1
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[hal-05630841] Etude des vésicules extra-cellulaires de Trichinella spp et de leur potentiel immunomodulateur
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ano.nymous@ccsd.cnrs.fr.invalid (Jana Dhaybi) 22 May 2026
https://hal.science/hal-05630841v1
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[hal-05630924] Première identification moléculaire de Cryptosporidium spp. et Giardia duodenalis chez les pigeons en France : implications dans l’approche One Health.
Les pigeons (Columba livia domestica et Columba palumbus) sont des espèces ubiquistes présentes dans les villes du monde entier. Leur interaction avec les humains, les animaux domestiques et les oiseaux sauvages en fait des porteurs potentiels d’agents pathogènes transmissibles, notamment des parasites zoonotiques. L’objectif de cette étude était d’identifier des protozoaires appartenant aux genres Cryptosporidium et Giardia chez ces deux espèces de pigeons hébergées au Centre Hospitalier Universitaire Vétérinaire de la Faune Sauvage (CHUVFS) de l’École nationale vétérinaire d’Alfort, en France. Des échantillons fécaux provenant de 371 pigeons (Columba livia et Columba palumbus), dont une large majorité de juvéniles, ont été collectés et analysés à l’aide de l’immunofluorescence directe ainsi que des techniques d’identification moléculaire (PCR 18S rRNA et gp60). Quatre-vingt-six et douze échantillons fécaux se sont révélés positifs respectivement pour Cryptosporidium spp. et Giardia spp. par immunofluorescence. Les jeunes pigeons semblaient être infectés par Cryptosporidium spp. plus fréquemment que les adultes. De plus, les pigeons ramiers semblaient être plus souvent infectés par Giardia spp., tandis que les pigeons bisets présentaient une prévalence plus élevée de Cryptosporidium spp. L’analyse moléculaire a révélé la présence d’espèces zoonotiques, notamment Cryptosporidium meleagridis, Cryptosporidium parvum et Giardia duodenalis assemblage B. Étant donné que ces espèces sont connues pour infecter l’être humain, les pigeons pourraient représenter une source potentielle de transmission zoonotique.
ano.nymous@ccsd.cnrs.fr.invalid (Anaïs Devulder) 22 May 2026
https://hal.science/hal-05630924v1
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[hal-05631013] Muscarinic Receptors Signalling in the Regulation of Tick Salivation
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ano.nymous@ccsd.cnrs.fr.invalid (Caina Ning) 22 May 2026
https://hal.inrae.fr/hal-05631013v1
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[hal-05619594] Stomoxys calcitrans as a potential mechanical vector of Anaplasma phagocytophilum : assessment through original ex vivo feeding models
Granulocytic anaplasmosis is a zoonotic disease that affects various domestic mammals (dogs, horses, and, more rarely, cats). In ruminants, it is better known as tick-borne fever (TBF) and is responsible for significant economic losses on European livestock farms, mainly due to a drop in milk production, abortions, and immunosuppression, which can lead to secondary infections. The disease is caused by the strictly intracellular bacterium Anaplasma phagocytophilum , whose biological vectors are ticks of the genus Ixodes . Other blood-feeding arthropods may be involved in transmitting this bacterium, notably Stomoxys calcitrans , a major ectoparasite of livestock that is implicated in transmitting other pathogens, including bacteria of the genus Anaplasma . This study aimed to evaluate the potential of S. calcitrans to act as a mechanical vector of A. phagocytophilum under laboratory conditions. Two experimental models were employed: one mimicking immediate transmission, and the other delayed transmission. In both models, A. phagocytophilum DNA and RNA were detected in S. calcitrans for the first time, but no traces of the bacterium’s DNA or RNA were found in the glass feeder’s blood. Further research is needed to confirm these findings through field studies investigating the presence of the bacterium in flies under natural conditions. This study also describes two original infection models of stable flies designed to reproduce their ex vivo blood-feeding, promoting alternative experimental approaches in accordance with animal welfare regulations and 4R principles.
ano.nymous@ccsd.cnrs.fr.invalid (Clotilde Rouxel) 12 May 2026
https://hal.science/hal-05619594v1
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[hal-05618689] A Bayesian modelling framework for estimating tick-borne pathogen transmission dynamics at the host-tick interface
Understanding the transmission dynamics of tick-borne pathogens at the host-tick interface is challenged by the presence of multiple pathways for tick infection, including (i) host-to-tick transmission, (ii) tick-to-tick (cofeeding) transmission, and (iii) pre-existing infection through vertical transmission or prior feeding. Assessing parameters governing these pathways is critical for identifying the main transmission drivers and, consequently, key prevention and control points. Here, we developed a Bayesian modelling framework that estimates key parameters describing the probability of each transmission pathway and assesses associated factors, including bird species, tick life stage and engorgement level, by jointly modelling transmission at the host-tick interface using data collected in field studies that sample hosts and their ticks. First, by fitting the model to simulated host-tick infection data, we demonstrated the framework’s ability to recover the parameter values underlying these data. Model performance improved significantly when more information was available on variability in cofeeding probability among individual ticks, highlighting the value of testing all collected ticks and recording their spatial distribution on the host in relation to each other. Second, we fitted the model to field data collected at the bird-tick interface in Northeast France in 2023, focusing on Borrelia garinii , B. valaisiana , and Anaplasma phagocytophilum as case pathogens. For all three pathogens studied, models including cofeeding transmission explained the data significantly better than models that did not. Engorgement level was significantly and positively associated with the probability of bird-to-tick transmission for A. phagocytophilum . Finally, the estimated parameters, such as the probability of A. phagocytophilum infection in birds and the probability of Borrelia or Anaplasma infection in ticks before feeding, were comparable to values from an external dataset, not used for model fitting. Our framework provides a valuable foundation for future research to understand tick-borne pathogen transmission dynamics based on epidemiological and ecological field data collected at the host-tick interface.
ano.nymous@ccsd.cnrs.fr.invalid (Younjung Kim) 11 May 2026
https://hal.science/hal-05618689v1
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[hal-05551639] Yeast probiotic protects gut microbiota diversity and metabolic potential against Cryptosporidiosis-induced disruption in goat kids
Cryptosporidiosis, caused by Cryptosporidium parvum, is a major cause of enteric disease and gut microbiota disruption in neonatal ruminants. It can lead to impaired growth, increased susceptibility to pathogens, and longterm gut dysfunction. In this study, we investigated whether supplementation with a live yeast probiotic (Saccharomyces cerevisiae Sc47) could help preserve gut microbiota resilience and functional homeostasis during an experimental C. parvum oral infection in goat kids. Thirty male French Alpine goat kids were assigned to three groups: uninfected control (healthy), infected, and infected with yeast supplementation. Longitudinal 16S rRNA gene sequencing, network analysis, and functional metagenomic predictions were used to assess microbial diversity, community composition, co-occurrence patterns, and metabolic potential, with a focus on short-chain fatty acid (SCFA) biosynthesis. Infection induced marked dysbiosis, characterised by a substantial reduction in microbial richness and a widespread loss of SCFA-producing commensals and metabolic functions. In contrast, yeast supplementation significantly reduced oocyst excretion by more than 84% throughout the experiment, attenuated pathogen-induced community shifts, and maintained beneficial genera such as Butyricicoccus and members of the Oscillospiraceae family. Furthermore, network analysis revealed that probiotic treatment preserved microbial association structures and reduced community fragmentation. Consistent with these findings, functional profiling showed the retention of pathways involved in carbohydrate metabolism, amino acid biosynthesis, and SCFA production, suggesting enhanced microbiota resilience. These findings demonstrate that S. cerevisiae supplementation can mitigate infection-associated dysbiosis by controlling pathogenic overgrowth while sustaining commensal bacterial stability and functional capacity. This highlights its potential as a microbiota-targeted strategy to support gut health in neonatal ruminants.
ano.nymous@ccsd.cnrs.fr.invalid (Mohamed Mammeri) 22 May 2026
https://hal.science/hal-05551639v1
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[hal-05630823] Evaluation of Trichinella’s extracellular vesicules involvement in the interactions with the host.
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ano.nymous@ccsd.cnrs.fr.invalid (Jana Dhaybi) 22 May 2026
https://hal.science/hal-05630823v1
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[hal-05630749] La giardiose chez les animaux de production
Giardiasis is an intestinal infection caused by a protozoan parasite, commonly affecting young production animals, including calves, goat kids, and lambs. Often asymptomatic or responsible for mild digestive signs, it can impair growth and reduce farm profitability. The parasite alternates between trophozoite and cyst stages, with the latter ensuring fecal–oral transmission. Genotypes, known as assemblages, exhibit variable host specificity, with assemblage E predominating in ruminants and pigs. Diagnosis relies on coproscopy, direct immunofluorescence assays, or PCR. No treatment is officially authorised in France, although fenbendazole and albendazole have proven efficacy. Prevention primarily depends on strict hygiene measures. Giardiasis is also a potential zoonosis, although strains found in livestock rarely pose a risk to humans. A management strategy, combining detection, rational treatment, and biosecurity, can help mitigate its impacts.
ano.nymous@ccsd.cnrs.fr.invalid (Mohamed Mammeri) 22 May 2026
https://hal.science/hal-05630749v1
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[hal-05569061] Méthodes de diagnostic de l’infection par Cryptosporidium spp. chez les ruminants: connaissances actuelles et tendances futurs
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.
ano.nymous@ccsd.cnrs.fr.invalid (Faten Bouaicha) 26 Mar 2026
https://hal.science/hal-05569061v1
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[hal-05630788] Bafilomycin A1 is a promising therapeutic agent against T. spiralis infection by inhibiting the heme-transporting ATP6V0C/HRG-1 complex
Trichinella spiralis ( T. spiralis ), a zoonotic nematode that causes severe myositis and systemic morbidity, sustains chronic muscle parasitism through evolutionary adaptations; however, this globally prevalent disease lacks targeted therapies to disrupt chronic infection. Although the heme transport protein HRG-1 has been characterized as an intervention target in free-living species (e.g., Caenorhabditis elegans ) and hematophagous parasites (e.g., Haemonchus contortus ), the molecular machinery governing heme acquisition in the nonhematophagous parasite T. spiralis remains uncharacterized, and no drugs targeting HRG-1 have been reported until now. Herein, we demonstrate that T. spiralis , a parasite that lacks the ability to synthesize heme autonomously, has evolved a sophisticated mechanism to scavenge and utilize heme from its host. By employing an aspartic protease to degrade host hemoglobin and myoglobin in the parasitic niche, T. spiralis is able to liberate heme for its own growth and survival. The structurally and functionally conserved Ts -HRG-1 protein plays a key role in transporting heme to the entire worm, particularly to functional organs, such as the cuticle and stichosome. More importantly, we discovered that the interaction between Ts -HRG-1 and Ts -ATP6V0C results in the formation of a functional complex that is essential for the parasite’s heme acquisition. The intervention effect achieved by Ts -ATP6V0C RNAi or inhibiting the activity of Ts -ATP6V0C with bafilomycin A1 (BafA1) was consistent with Ts -HRG-1 RNAi, resulting in impaired heme uptake, developmental arrest and a reduced larval burden in mouse hosts. These findings enhance our understanding of the parasite’s heme acquisition mechanism and identify the development of drugs that target proteins that interact with HRG-1 as a new direction in anthelminthic drug research.
ano.nymous@ccsd.cnrs.fr.invalid (Yushu He) 22 May 2026
https://hal.science/hal-05630788v1
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[hal-05630917] Biothérapies à base d’hydrolases des sels biliaires dans la lutte contre la giardiose
La giardiose est une parasitose intes>nale causée par le protozoaire Giardia intesPnalis. L’infec>on, transmise par voie fécale-orale, peut provoquer des diges>fs chroniques, comme le syndrome de l’intes>n irritable (SII) chez l’humain ou des retards de développement chez l’enfant. Malgré les traitements an>parasitaires disponibles, notamment les dérivés nitroimidazolés, des limites persistent, en par>culier l’émergence de résistances associée à des échecs thérapeu>ques. Le développement de stratégies alterna>ves ou complémentaires à la chimiothérapie an>parasitaire classique apparaît nécessaire (1). Ainsi, la souche Lactobacillus johnsonii CNCM I-4884 a été sélec>onnée comme souche probio>que possédant une ac>vité an>-Giardia in vitro et in vivo (1-2). Ce\e souche inhibe la croissance de G. intesPnalis via ses ac>vités enzyma>ques d’hydrolases des sels biliaires (BSH), qui conver>ssent les acides biliaires conjugués présents dans la bile, en acides biliaires déconjugués dont certains sont toxiques pour le parasite. Afin de valider le rôle central des BSH dans le contrôle de Giardia, ce\e bactérie probio>que a été placée à une pression de sélec>on visant à augmenter son ac>vité BSH ; les dérivés obtenus se sont alors révélés plus efficaces contre le parasite. Aussi, nous avons modifié géné>quement la souche sauvage de Lj CNCM-I-4884 afin de surexprimer l’une et/ou l’autre de ses deux BSHs (BSH405, BSH1011, ou les deux simultanément). Enfin, les souches dérivées (la souche issue de la pression de sélec>on et les deux souches géné>quement modifiées) ont significa>vement réduite la croissance in vitro des trophozoïtes de G. intesPnalis, par rapport à la souche sauvage Lj CNCM-I-4884. Ces données suggèrent que l’u>lisa>on de bactéries sélec>onnées ou géné>quement modifiées pour surexprimer des ac>vités BSH pourraient cons>tuer une approche innovante dans la lu\e contre la giardiose, soit en tant qu’alterna>ve, soit en complément des traitements an>parasitaires existants. A terme, ce type de stratégie pourrait contribuer à réduire les problèmes de résistance et à améliorer la prise en charge des infec>ons parasitaires intes>nales. References: (1) Allain T.; Chaouch S.; Thomas M.; Travers M.-A.; Valle I.; Langella P.; Grellier P.; Polack B.; Florent I.; Bermudez-Humaran L.G. Bile Salt Hydrolase AcRviRes: A Novel Target to Screen AnR-Giardia Lactobacilli? Front. Microbiol., 2018. 9, 89. hWps://doi.org/10.3389/fmicb.2018.00089 (2) Boucard A.-S.; Florent I.; Polack B.; Langella P.; Bermudez-Humaran L.G. Genome Sequence and Assessment of Safety and PotenRal ProbioRc Traits of Lactobacillus johnsonii CNCM I-4884. Microorganisms, 2022. 10(2), 273. hWps://doi.org/10.3390/microorganisms10020273
ano.nymous@ccsd.cnrs.fr.invalid (Damien Oliveira) 22 May 2026
https://hal.science/hal-05630917v1
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[hal-05619643] Dynamique saisonnière et évaluation des agents pathogènes transmis par Ixodes ricinus en France, 2018-2024.
Ixodes ricinus est la tique la plus largement répandue en France et constitue un vecteur majeur de nombreux agents pathogènes d’importance médicale et vétérinaire. Son écologie, son cycle triphasique et sa sensibilité aux paramètres climatiques en font un modèle pertinent pour l’étude des dynamiques éco-épidémiologiques. Le changement climatique a favorisé l’expansion de son aire de répartition vers des altitudes et latitudes plus élevées. Ces modifications, associées à des facteurs écologiques et anthropiques — tels que la répartition et le comportement des hôtes, ainsi que les activités humaines — influencent la dynamique saisonnière des tiques et les interactions tiques-animaux-humains, ce qui augmente le risque de transmission des agents pathogènes. Cependant, peu d’études longitudinales ont été menées en zones périurbaines pour documenter l’évolution de ces interactions dans le temps. Cette étude vise à évaluer la variabilité saisonnière et interannuelle des agents pathogènes transmis par I. ricinus en France et à mieux comprendre les facteurs abiotiques influençant leur circulation. Une campagne de surveillance, menée de 2018 à 2024 dans la forêt périurbaine de Sénart (Île-de-France), a permis la collecte d’un total de 2092 nymphes en quête par la méthode du drap. Parmi elles, 849 nymphes ont été analysées par puce microfluidique, une PCR en temps réel à haut débit, ciblant 35 espèces d’agents pathogènes, 7 genres et 1 phylum. Notre étude montre une dynamique saisonnière stable d’une année à l’autre, avec un pic principal au printemps. Trois variables climatiques, le nombre de jours avec une température maximale supérieure à 25 °C, l’humidité moyenne mensuelle et la forte insolation, sont négativement corrélées à la densité des nymphes. Les agents pathogènes identifiés — principalement les genres Anaplasma, Borrelia, Rickettsia et Babesia — reflètent la diversité classique rapportée en Europe de l’Ouest et leur présence récurrente depuis 2014 suggère une circulation stable et endémique dans cette forêt. Cette étude souligne l’importance de dispositifs de surveillance longitudinale pour mieux anticiper les fluctuations des populations de tiques et de leurs agents pathogènes, et d’orienter les stratégies de prévention et la sensibilisation du public. Le suivi régulier des animaux sauvages et des conditions microclimatiques demeure essentiel pour réduire le risque d’exposition humaine.
ano.nymous@ccsd.cnrs.fr.invalid (Paloma Kiwan) 12 May 2026
https://hal.science/hal-05619643v1
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[hal-05543411] Optimiser la production du génome d'Anaplasma phagocytophilum, une étape cruciale pour comprendre la virulence et le tropisme d'hôte
Anaplasma phagocytophilum (Aph) est une bactérie intracellulaire stricte transmise par les tiques du genre Ixodes, responsable de l’anaplasmose granulocytaire chez l’Homme et les ruminants. La variabilité de la virulence et la diversité des hôtes suggèrent une diversité génétique encore mal caractérisée. L’analyse génomique d’Aph demeure complexe en raison de la difficulté à isoler et cultiver la bactérie, ainsi qu’à séparer son ADN de celui de l’hôte vertébré. Ce projet vise (i) à évaluer la qualité des génomes disponibles dans les bases publiques et (ii) à développer une stratégie de séquençage long-read Oxford Nanopore Technologies (ONT®) permettant d’obtenir des génomes complets et d’origine plus diversifiée. En 2025, nous avons évalué 33 génomes Aph disponibles sur NCBI pour leur fragmentation, leur taille (QUAST) et leur pureté (BLAST, Kraken2). Vingt-neuf présentaient une qualité et une complétude satisfaisantes, tandis que 4 présentaient une contamination importante par des séquences hôtes. Un séquençage ONT d’une souche de source humaine enrichie en culture a permis d’obtenir, après sous-échantillonnage d’une profondeur de séquençage de 100X, un génome complet en un seul contig (~1,5 Mb). Des simulations de profondeurs variables (10X à 100X, 10 réplicas) ont montré qu’une couverture de 30X permettait l’assemblage d’un génome complet équivalent au contrôle. Nous avons également mis en évidence qu’à 20X les génomes étaient de taille attendue malgré une fragmentation plus importante (>5 contigs), et qu’à 10X le génome était fragmenté et incomplet. Les analyses de clustering par k-mer ont révélé que dès 20X, les topologies d’arbre étaient stables, indiquant que cette profondeur est suffisante pour des comparaisons robustes de génomes. Des essais de séquençage réel utilisant la technologie ONT® sur des cultures présentant différents ratios hôte/Aph (1 et 10 %) et utilisant « l’adaptive sampling » pour enrichir en temps réel la fraction d’ADN bactérien ont permis d’atteindre des profondeurs de 7X et 65X. Des optimisations restent nécessaires pour améliorer l’enrichissement et le multiplexage des échantillons. Notre preuve de concept démontre la faisabilité du séquençage ONT® d’Aph à partir d’échantillons faiblement enrichis et ouvre la voie au séquençage de génomes plus diversifiés qui permettront d’approfondir les connaissances épidémiologiques sur Aph.
ano.nymous@ccsd.cnrs.fr.invalid (Clotilde Rouxel) 09 Mar 2026
https://hal.science/hal-05543411v1
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[hal-05619073] Exploration des interactions virus-bactéries chez Ixodes ricinus à l'aide d'un modèle d'infection artificielle
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Evan Bouton) 11 May 2026
https://hal.science/hal-05619073v1
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[hal-05584628] Etude des endosymbiotes et pathogènes chez les Afrixodes (Acari : Ixodidae, Ixodes) d’Afrique tropicale à l’Université d’Hokkaido : Retour d’expérience d’une mobilité de 3 mois au Japon
En plus d’être un taxon très peu étudié, en termes de taxonomie et d’écologie, il n’existe que quelque rares études sur les endosymbiotes et pathogènes chez le sous genre Afrixodes. Sur les 65 espèces recensées, seules cinq espèces ont fait l’objet de ce genre d’étude, ne décelant que quatre genres de pathogènes (Anaplasma spp., Babesia spp., Ehrlichia spp. et Rickettsia spp.) et quatre genres associés à des endosymbiotes (Coxiella spp., Midichloria spp., Rickettsia spp. et Spiroplasma spp.). Afin d’enrichir les connaissances dans l’étude de ce taxon et dans la perspective d’approches One Health, une collaboration de trois mois a été mise en place en 2025 entre l’UMR BIPAR (ANSES, ENVA, INRAE) et l’équipe de Parasitologie de la Faculté de Médecine Vétérinaire de l’Université d’Hokkaido (Sapporo, Japon). Spécialisée dans ce genre d’étude, et particulièrement sur les tiques dures d’Afrique, l’équipe du Dr Ryo Nakao a développé de nouvelles amorces pour la détection de 9 genres différents d’endosymbiotes et de pathogènes, ciblant 2 gènes différents par genre, en plus d’amorces spécifiques pour l’identification des Afrixodes. Cela a permis de séquencer les ADN, extraits de façon non-destructive, de 120 spécimens d’Afrixodes, grâce au séquençage NextSeq Illumina. Notre communication détaille le déroulement de cette mobilité ; incluant la présentation du laboratoire, la recherche de financement, l’élaboration du protocole et les résultats préliminaires obtenus. L’ensemble des résultats seront présentés lors de la soutenance de ma thèse en septembre prochain.
ano.nymous@ccsd.cnrs.fr.invalid (Camille Lorang) 08 Apr 2026
https://hal.science/hal-05584628v1
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[hal-05627132] Parasites vectorisés par les tiques chez le chat : rôle de la faune sauvage urbaine
Avec 16,6 millions d'individus en 2024, la population de chats domestiques en France est en constante augmentation, accentuant le risque d'exposition aux tiques et aux agents pathogènes vectorisés. Notre étude explore le rôle de la faune sauvage urbaine comme réservoir de ces maladies, notamment des parasites vectorisés. Entre 2023 et 2024, 131 tiques ixodidés et des prélèvements sanguins de 110 hérissons européens (Erinaceus europaeus) issus de l'Hôpital de la Faune Sauvage de l’Ecole nationale vétérinaire d’Alfort ont été analysés par PCR et séquençage. Après l’identification morphologique et moléculaire des tiques récoltées, nous avons détecté la présence d’ADN de parasites tels qu’Hepatozoon sp. et Cytauxzoon sp. chez les tiques et les hérissons. Nos résultats soulignent l'importance d'approfondir la surveillance de la prévalence parasitaire chez le chat et de préciser le rôle de réservoir joué par la faune sauvage de proximité.
ano.nymous@ccsd.cnrs.fr.invalid (Veronica Risco-Castillo) 20 May 2026
https://hal.science/hal-05627132v1
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[hal-05630703] Cryptosporidiose et microbiote intestinal des nouveau-nés : piste de nouvelles thérapies alternatives
La cryptosporidiose est une zoonose majeure responsable de diarrhées néonatales chez les jeunes ruminants, sans traitement pleinement efficace à ce jour chez l’animal comme chez l’Homme. Cryptosporidium parvum, parasite intracellulaire particulièrement résistant, perturbe l’équilibre intestinal et contribue à une forte contamination environnementale. Le microbiote intestinal joue un rôle central dans la digestion, l’immunité et la protection contre les pathogènes, mais son interaction avec C. parvum reste encore peu explorée chez les jeunes animaux. Cette étude vise à évaluer l’intérêt de la supplémentation en levures vivantes (Saccharomyces cerevisiae Sc 3-A et Sc 5) chez des chevreaux nouveau-nés infectés expérimentalement. Les résultats montrent une amélioration significative de l’état général, du gain de poids et une réduction de l’intensité et de la durée de la diarrhée, avec une efficacité supérieure pour la souche Sc 5. La supplémentation module favorablement le microbiote intestinal et limite la prolifération parasitaire, ouvrant la voie à des stratégies alternatives prometteuses de prévention de la cryptosporidiose
ano.nymous@ccsd.cnrs.fr.invalid (Mohamed Mammeri) 22 May 2026
https://hal.science/hal-05630703v1
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[hal-05630723] La cryptosporidiose chez les ruminants nouveau-nés en France : enjeux vétérinaires
Cryptosporidium est un parasite protozoaire intracellulaire obligatoire capable d’infecter une grande diversité d’hôtes vertébrés, provoquant des affections intestinales parfois sévères chez les animaux et chez l’homme. La cryptosporidiose constitue un problème sanitaire majeur chez les ruminants nouveau-nés, chez lesquels elle est fréquemment associée à des diarrhées néonatales et à des pertes économiques importantes. Cette infection figure également parmi les maladies d’origine hydrique et alimentaire les plus répandues à l’échelle mondiale. Parmi les espèces du genre, Cryptosporidium parvum se distingue par son fort potentiel zoonotique et sa capacité à induire des formes cliniques graves chez l’homme, notamment chez les jeunes enfants et les individus immunodéprimés. En France, la cryptosporidiose représente un enjeu croissant de santé publique et de santé animale. Cette communication se propose d’examiner l’importance et l’impact de cette parasitose chez le bétail, en mettant l’accent sur les ruminants domestiques tels que les bovins, les ovins et les caprins. Ces espèces animales doivent être considérées comme des réservoirs potentiels de transmission zoonotique de Cryptosporidium.
ano.nymous@ccsd.cnrs.fr.invalid (Mohamed Mammeri) 22 May 2026
https://hal.science/hal-05630723v1
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[hal-05499947] Distribution of tick-borne microorganisms in human-biting ticks in France collected through a Citizen-science program
Ticks occupy diverse habitats, increasing the risk of human exposure. Assessing the public health threat posed by ticks requires rigorous monitoring of their distribution and of the prevalence of tick-borne pathogens. In France since 2017, the citizen science program CiTIQUE monitors human tick bites through multiple complementary approaches. Citizens can report bites and submit biting ticks to a national tick bank for research and surveillance. This study aimed to investigate human exposure to tick-borne microorganisms including pathogens across France, using ticks submitted through the CiTIQUE program. In total, 2009 ticks were selected from the CiTIQUE tick bank, identified, and screened for microorganisms using a real-time microfluidic PCR method. Most bites involved Ixodes ricinus nymphs except in Mediterranean regions where Dermacentor and Rhipicephalus ticks were more common. Twenty-six microorganisms were detected, eighteen of which are potentially pathogenic to humans. These pathogens were widely distributed across the country. Borrelia spp. were the most frequently detected pathogens with spatial variation among regions. Anaplasma phagocytophilum infection rates varied from region to region. Neoehrlichia mikurensis was found in seven out of twelve French regions. Rickettsia species diversity was highest in the southeast, associated with a greater diversity of vectors. Five percent of ticks were infected with more than one pathogen. Although spatial heterogeneity was observed, no region was free of infected ticks. This study demonstrates the power of citizen science for nationwide surveillance of tick-borne pathogens, providing a large-scale overview of pathogen diversity and distribution across France from crowdsourced tick data.
ano.nymous@ccsd.cnrs.fr.invalid (Jonas Durand) 09 Feb 2026
https://hal.inrae.fr/hal-05499947v1
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[hal-05551630] Microbial network stability, not diversity, drives colonization resistance against Borrelia afzelii in Ixodes ricinus ticks
Most tick-borne pathogens (TBPs) are acquired secondarily, when ticks feed on infected hosts, meaning the pathogen must establish itself within an already assembled microbiota. These scenarios are subject to "priority effects," where the order of microbial arrival influences the success of later colonizers. Microbial interactions within arthropod vectors can therefore shape infection outcomes, producing either infection-refractory states, where resident microbes and their interactions reduce the likelihood of pathogen establishment, or infectionpermissive states, where such barriers are absent or weakened and the pathogen establishes infection successfully. Hamilton et al. (2021) assessed larval microbiota before pathogen exposure and sequenced the microbiota of fed nymphs, both exposed or not to Borrelia afzelii, enabling priority-effect hypotheses to be tested. Despite uniform exposure to the highly infectious B. afzelii strain NE4049, only a subset of ticks became Borrelia-positive, suggesting refractory and permissive microbiota states. We reanalyzed the original dataset to test whether differences in microbiome community assembly and co-occurrence network features, beyond diversity metrics, were associated with these states. Refractory nymph networks exhibited higher connectivity and structural resilience, with Staphylococcus emerging as a central taxon already present in unfed larvae. In contrast, permissive networks showed reduced robustness and a marginal role for Staphylococcus. Notably, dysbiosis altered microbial assembly but did not prevent network reconfiguration in refractory ticks. Our findings suggest that colonization resistance is better explained by microbial network integrity than by diversity alone. Methodologically, they show that integrating community assembly theory and network analyses can reveal key features of the tick microbiota associated with vector competence.
ano.nymous@ccsd.cnrs.fr.invalid (Lianet Abuin-Denis) 13 Mar 2026
https://hal.science/hal-05551630v1
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[hal-05551814] Detection of Multiple Microorganisms in Ruminant Ticks in Senegal Using High‐Throughput Microfluidic Real‐Time PCR
Ticks are major vectors of numerous pathogens affecting both livestock and humans. In Senegal, data on the diversity of tick‐borne pathogens (TBPs) in ruminant‐associated ticks remain limited. In total, 1703 ticks were collected from goats, sheep, and cattle across three ecological zones of Senegal (Sudanian, Sahelian, and Sudano‐Sahelian). Tick species were identified morphologically, and 300 individuals were screened for 36 microorganisms using a high‐throughput microfluidic real‐time PCR system. DNA was successfully extracted and amplified from 289 ticks. The most abundant species were Rhipicephalus evertsi evertsi (32.3%), Hyalomma truncatum (19.6%), R. guilhoni (15.6%), H. rufipes (11.6%), and Amblyomma variegatum (11.0%). Among the screened ticks, 226 (78.9%) were positive for at least one microorganism. True pathogens of veterinary and/or zoonotic importance included Anaplasma ovis (30.8%), Coxiella spp. (23.9%), Rickettsia aeschlimannii (13.1%), Theileria spp. (11.1%), and Ehrlichia canis (4.8%), with sporadic detections of Anaplasma marginale , A. bovis , and Babesia spp. (0.3% each). In addition, non‐pathogenic Francisella ‐like endosymbionts (FLEs) were detected at high prevalence (37.4%) across all ecological zones. The presence of TBPs and/or endosymbionts was significantly associated only with the tick’s host in the multivariable logistic regression model. Ticks collected from goats (OR = 7.82; p = 0.024) and sheep (OR = 7.70; p = 0.015) were significantly more likely to be infected than those collected from cattle (reference group). A total of 96 cases of microorganism co‐occurrence were recorded across different tick species. Co‐infections were more frequent in ticks collected from the Sudano‐Sahelian zone (48.2%) and in those from sheep (32.0%). None of the detected microorganism species showed a significant associated with tick sex. This study represents the first large‐scale molecular survey of TBPs in ruminant‐associated ticks in Senegal, revealing both a high diversity of pathogens and a widespread presence of tick endosymbionts. While endosymbionts, such as FLEs, are not known to be pathogenic, their abundance may influence tick physiology and vector competence. The detection of zoonotic pathogens, such as E. canis and R. aeschlimannii , underscores the need to strengthen tick surveillance and investigate their potential public health implications.
ano.nymous@ccsd.cnrs.fr.invalid (Aliou Khoule) 13 Mar 2026
https://hal.science/hal-05551814v1
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[hal-05551612] Characterizing the Bacterial Microbiome of the Invasive Vector Aedes albopictus in Hungary: A Pilot Study Using Oxford Nanopore Sequencing
Aedes albopictus has recently established self‐sustaining populations in Hungary, but its microbiota—which may influence vector competence—remains poorly understood. We used Oxford Nanopore long‐read sequencing for full‐length 16S rRNA gene profiling of adult Ae. albopictus from two urban sites, Pécs and Barcs. Each location contributed 10 specimens, with contamination controls rigorously applied. Diversity metrics and co‐occurrence network analyses were performed using QIIME2, SparCC, and NetCoMi, with robustness assessed via simulated node removal and addition. Sequencing depth was sufficient to saturate rarefaction curves. Although alpha and beta diversity did not differ significantly between sites, the Pécs population exhibited greater taxonomic richness (100 unique taxa vs. 61 in Barcs) and denser, more clustered networks. Only 15 genera were shared, with Wolbachia dominating both communities. Networks differed in central taxa and structural properties: Pécs retained higher connectivity and shorter paths under perturbation, suggesting greater resilience. Removal of conserved taxa revealed location‐specific impacts on network stability, with Pécs more vulnerable to the loss of key genera. Negative interactions and compensatory taxa emerged post‐removal, indicating distinct reconfiguration strategies. Our findings highlight marked local variation in microbiome structure and robustness, even across a 65‐km gradient. These results establish a high‐resolution baseline for assessing how microbiota shape Ae. albopictus vector potential, informing microbiome‐based control strategies tailored to regional contexts.
ano.nymous@ccsd.cnrs.fr.invalid (Kornélia Kurucz) 13 Mar 2026
https://hal.science/hal-05551612v1
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[hal-05551805] High-throughput screening for tick-borne pathogens in Ixodid ticks collected through crowdsourcing in northern Sweden
Abstract 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.
ano.nymous@ccsd.cnrs.fr.invalid (Giulio Grandi) 13 Mar 2026
https://hal.science/hal-05551805v1
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[hal-05342360] Distribution of Giardia duodenalis genotypes in diarrheic children from Algiers, Algeria
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ano.nymous@ccsd.cnrs.fr.invalid (Djamel Baroudi) 02 Nov 2025
https://hal.inrae.fr/hal-05342360v1
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[hal-05482080] Successful Treatment of Cutaneous Lupus Erythematosus in a Horse With Tacrolimus Ointment
A 9‐year‐old gelding Quarter Horse with a lesion on the right upper eyelid was diagnosed with cutaneous lupus erythematosus. Clinical resolution and control of UV‐induced flares were achieved with topical tacrolimus and a UV‐blocking mask without adverse effects over the following 3 years.
ano.nymous@ccsd.cnrs.fr.invalid (Hélène Dropsy) 28 Jan 2026
https://hal.science/hal-05482080v1
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[hal-05495074] Two types of axonal muscarinic acetylcholine receptors mediate formation of saliva cocktail in the tick Ixodes ricinus
Hard ticks depend upon an ability to precisely and dynamically regulate their saliva to successfully evade host haemostatic and immune defences during extended blood feeding. Although pilocarpine, an exogenous muscarinic acetylcholine receptor (mAChR) agonist, can stimulate salivation experimentally, the endogenous control of saliva secretion by acetylcholine remains poorly understood. Here, we identify and characterise two pharmacologically distinct mAChRs (type A and B) in the genome of the medically important tick Ixodes ricinus . Molecular dynamics simulations and targeted mutagenesis reveal that type B mAChRs exhibit an atypical muscarinic profile, suggesting unconventional receptor signalling. Combining immunolabelling, in vivo pharmacology, and proteomics, we show that specific central neurons interact with distinct salivary gland regions via mAChR type-specific axons, coordinating fluid and protein secretion through separate acini and likely acting upstream of a neuropeptide-dependent cascade. This previously unrecognised mechanism of neural control offers new insights into how ticks modulate their saliva advancing our understanding of vector-host interactions, with potential implications for disrupting pathogen transmission.
ano.nymous@ccsd.cnrs.fr.invalid (Caina Ning) 03 Apr 2026
https://hal.inrae.fr/hal-05495074v1
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[hal-05397306] Are hydrophilic deep eutectic solvents a potential vehicle for topical delivery of Amphotericin B against cutaneous leishmaniasis? An investigation of physicochemical properties, tolerability and antileishmanial efficacy
Deep eutectic solvents (DES) are homogenous, low-melting mixtures that are liquid at ambient temperature. Recently, DES have attracted interest as novel alternatives to traditional solvents in cutaneous formulations. The aim of this work was to have a better understanding of whether DES could be a safe and effective vehicle for topical delivery of Amphotericin B (AmB) in Cutaneous Leishmaniasis (CL). Based on solubility data, solutions of AmB in DES were prepared and characterized in terms of rheological properties, stability, and aggregation state of AmB by circular dichroism. The tolerability of DES-AmB on the skin was investigated by combining noninvasive techniques with histological assessment; systemic toxicity was also studied. Finally, the best-tolerated formulations were selected for direct assessment of both therapeutic efficacy and toxicity in a murine model of CL. Some of the formulations, especially those based on L-carnitine, could be promising candidates for further development of effective drug formulations against CL, as they were able to show either partial antileishmanial or palliative effects in robust test conditions. However, further optimization is necessary to ensure optimal stability and efficacy of the formulations.
ano.nymous@ccsd.cnrs.fr.invalid (Cảnh Hưng Nguyễn) 04 Dec 2025
https://hal.science/hal-05397306v1
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[hal-05469047] Transcriptomic plasticity in hybrid schistosomes can contribute to their zoonotic potential
Hybrids between Schistosoma haematobium and Schistosoma bovis contribute to human and animal infections, highlighting complex interspecies interactions that facilitate schistosomiasis transmission. Schistosoma bovis infects multiple ruminant hosts, promoting cross-species transmission and increasing zoonotic risk. This study explores transcriptomic plasticity as a mechanism enabling hybrid schistosomes to adapt to different definitive hosts. We analysed two contexts: (1) introgressed S. haematobium × S. bovis hybrids, which exhibited higher virulence in sheep than parental S. bovis; and (2) S. bovis infecting different mammalian hosts. Introgression, the transfer of genetic material between species through hybridization and repeated backcrossing, was associated with 366 differentially expressed genes (4% of coding genes) between introgressed hybrids and S. bovis in sheep. Additionally, S. bovis showed host-dependent transcriptomic changes, with 30% of genes differentially expressed between infections in hamsters and sheep. Enriched biological processes shared across introgression and host adaptation included nuclear mRNA catabolism and inner mitochondrial membrane organization, indicating increased gene expression plasticity and metabolic adaptation to environmental stress. These findings suggest that transcriptomic plasticity enhances the adaptability of S. bovis and hybrid worms, increasing their zoonotic potential. This raises concerns for schistosomiasis control, as such plasticity could expand transmission capacity and complicate intervention strategies. This article is part of the Royal Society Science+ meeting issue ‘Parasite evolution and impact in action: exploring the importance and control of hybrid schistosomes in Africa and beyond’.
ano.nymous@ccsd.cnrs.fr.invalid (Nelia Luviano Aparicio) 21 Jan 2026
https://hal.science/hal-05469047v1
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[hal-05595854] Peace: an Indispensable Foundation for Operationalizing the One Health Paradigm
En tant que parasitologues spécialisés dans les maladies parasitaires humaines et animales, nous exprimons notre profonde inquiétude face à la détérioration du climat géopolitique mondial. La science n’a jamais été une entreprise isolée ; elle est un pont construit sur l’échange libre d’idées, indépendamment des origines, des religions ou des nationalités. Notre domaine, une mosaïque diversifiée de biologistes, écologues, pharmaciens, vétérinaires et médecins, est intrinsèquement transdisciplinaire et ne peut prospérer que lorsque la communauté internationale est unie dans la quête de la connaissance. Aujourd’hui, cette unité est brisée par le tumulte de nombreux conflits et guerres.
ano.nymous@ccsd.cnrs.fr.invalid (Jean Dupouy-Camet) 18 Apr 2026
https://hal.science/hal-05595854v1
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[hal-05618675] Surveillance of Zoonotic Pathogens in Small Mammals Across Forests With Different Levels of Anthropization in Eastern France
The emergence of infectious diseases associated with land‐use changes is well‐documented. However, the presence and dynamics of zoonotic pathogens in small mammals within European forests, whether from rural development or urban greening, remain underexplored. To describe zoonotic hazards in these ecosystems, and to assess the influence of biotic and abiotic factors on their distribution, we analyzed 1549 individuals from 18 small mammal species sampled across forest types representing different levels of anthropization using both targeted and broad‐spectrum serological and molecular methods. We detected nine bacteria and five Apicomplexa that are potentially pathogenic to humans. Zoonotic pathogen richness and community composition varied significantly across host species, sites, and sampling periods. Richness was lower in forested urban parks, possibly due to the absence of vectors or intermediate hosts within cities. It was higher in urban adapter species, even within a given forested habitat, emphasizing the important role of specific life‐history traits. Pathogen community structure was shaped by forest anthropization and host ecology, with marked differences between urban and rural forested environments and between urban adapter and dweller species within forested urban parks. The seroprevalence of key pathogens (e.g., Bartonella , Orthopoxvirus , Neoehrlichia mikurensis , and Sarcocystidae) showed spatial, temporal, and host‐specific variation. Epidemiological differences between sites often exceeded those between habitat types, in particular when comparing protected and managed forests, highlighting the importance of local ecological context. Nevertheless, some patterns reflected the influence of forest anthropization and species urban adaptation strategies for certain zoonotic agents. High anthropization in forests was associated with elevated Bartonella prevalence, driven by urban‐adapter species rather than forest dwellers, emphasizing local ecological interactions between hosts and pathogens. Besides, higher levels of Orthopoxvirus seroprevalence were associated with adapter species in protected forests where they might be more abundant. Altogether, these findings underscore the need for integrated and multipathogen wildlife surveillance to anticipate and mitigate disease risks at the human–environment–animal interface.
ano.nymous@ccsd.cnrs.fr.invalid (Marie Bouilloud) 20 May 2026
https://hal.science/hal-05618675v1
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[hal-05457299] Application of non-destructive DNA extraction for the molecular and morphological identification of tick species and their pathogens
Tick-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.
ano.nymous@ccsd.cnrs.fr.invalid (Camille Lorang) 14 Jan 2026
https://hal.science/hal-05457299v1
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[hal-05628395] Dermatite atopique et Dermatoses d’origine comportementale quand y penser
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ano.nymous@ccsd.cnrs.fr.invalid (Noëlle Cochet-Faivre) 20 May 2026
https://hal.science/hal-05628395v1
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[hal-05636363] A comparison of dog owners' use of and satisfaction with ectoparasiticides between the dermatology and preventive medicine departments at the veterinary University of Alfort in France
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ano.nymous@ccsd.cnrs.fr.invalid (Mathilde Collomb) 28 May 2026
https://hal.science/hal-05636363v1
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[hal-05460556] Impact of Lactobacillus johnsonii CNCM I-4884 on canine giardiasis: a probiotic-based approach
This 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.
ano.nymous@ccsd.cnrs.fr.invalid (Bruno Polack) 15 Jan 2026
https://hal.science/hal-05460556v1
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[hal-05470229] Unilateral accessory tragi in a cat
<div><p>An accessory tragus-a congenital malformation of part of the external ear-is an abnormal appendage developed from the first pharyngeal (or branchial) arch. In humans, an accessory tragus can be associated with other abnormalities as part of congenital malformative syndromes, most of which are transmitted in an autosomal dominant mode. Three cutaneous exophytic lesions were detected in the right preauricular region of a 2.5-y-old, castrated male European shorthair cat. Two of these lesions were submitted for histologic examination and were diagnosed as accessory tragi. They consisted of a vertical axis of loose collagenous tissue with hair follicles and sebaceous glands covered by a simple fold of epidermis. The epidermis was of normal thickness and slightly hyperpigmented. Only the pretragal lesion contained a central core of well-differentiated elastic cartilage. To our knowledge, accessory tragus has not been reported previously in cats and has been reported only once in veterinary medicine, in a dog with a solitary unilateral lesion. For pathologists, the diagnosis of this rare lesion may not be straightforward, especially if the cartilaginous core is absent or the location of the sample is unknown.</p></div>
ano.nymous@ccsd.cnrs.fr.invalid (Florine Brun) 21 Jan 2026
https://hal.science/hal-05470229v1
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[hal-05628267] Les défis diagnostiques et thérapeutiques en 2026 en oncodermatologie : quels pièges éviter, comment choisir la meilleure option thérapeutique chez un chat ou un chien ?
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ano.nymous@ccsd.cnrs.fr.invalid (Noëlle Cochet-Faivre) 20 May 2026
https://hal.science/hal-05628267v1
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[anses-05461390] Diversity of Ticks in the Caribbean Region and Detection of Their Pathogens Using BioMark Technology
Introduction Ticks and the pathogens they transmit are widespread in Caribbean animal populations. There is; however, limited information on the diversity of ticks and tick‐borne pathogens (TTBPs) in the region. This study aims to identify TTBPs across multiple Caribbean countries using a high‐throughput real‐time microfluidic PCR system. Methods Six Caribbean territories: Barbados, Guyana, St. Kitts, St. Lucia, Tobago and Trinidad were targeted in this study. Nucleic acids were extracted from individual ticks, and a high‐throughput microfluidic real‐time PCR system was used to screen for 49 bacterial species (10 genera) and 18 protozoan species (six genera). Five tick species were detected using morphological or molecular techniques. Results A total of 840 ticks were tested from 155 dogs and 111 cattle. Morphological and molecular diagnostic methods detected five tick species: Rhipicephalus sanguineus sensu lato (s.l.), Rhipicephalus microplus , Amblyomma variegatum , Amblyomma ovale and Amblyomma cajennense s.l. Overall, the DNA of 18 pathogens belonging to eight genera was detected in 22.5% (189/840) ticks obtained from both cattle (96/335) and dogs (93/505). The most prevalent pathogens were Anaplasma marginale 14% (47/335) and Hepatozoon canis 3.4% (17/505) in cattle and dog ticks, respectively. Dual and triple infections were also detected in 3.3% ( n = 28) and 0.6 % ( n = 5) of tested ticks, respectively. The DNA of Ehrlichia ruminantium was detected in R. sanguineus and A . variegatum from dogs in Barbados‐ a first record for this island. Another key finding was the novel detection of a Borrelia sp. in a R. sanguineus s.l. tick from Trinidad. Conclusion The high diversity of pathogens detected in this study, with some being of veterinary and public health importance, highlights the strength of the high‐throughput microfluidic real‐time PCR system as a surveillance tool for the efficient and rapid detection of tick‐borne pathogens (TBPs) of veterinary, public health and economic significance in the Caribbean.
ano.nymous@ccsd.cnrs.fr.invalid (Roxanne A. Charles) 16 Jan 2026
https://anses.hal.science/anses-05461390v1
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[tel-05407192] L’approche intégrée One Health en action : le cas des protistes zoonotiques Cryptosporidium et Giardia
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ano.nymous@ccsd.cnrs.fr.invalid (Mohamed Mammeri) 09 Dec 2025
https://hal.science/tel-05407192v1
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[hal-05454123] Cryptosporidium parvum et microbiote intestinal: Piste de stratégies alternatives thérapeutiques et préventives
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ano.nymous@ccsd.cnrs.fr.invalid (Karim Adjou) 12 Jan 2026
https://hal.inrae.fr/hal-05454123v1
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[hal-05535374] SARS-CoV-2 exposure in dogs before and after the largest COVID-19 wave in rural Guatemala, 2022
The SARS-CoV-2 pandemic disproportionately burdened low- and mid-income countries during many waves of high transmission, particularly in rural communities. We tested whether dogs from rural households were exposed to SARS-CoV-2 before and after the largest COVID-19 wave in Guatemala. We tested dogs in June and August 2022, before the rise and after the initial peak of the second Omicron wave, respectively. None of the 133 dogs tested (63 tested in June and 70 tested in August) had evidence of SARS-CoV-2 RNA in respiratory swabs. Three dogs in June and ve dogs in August had neutralizing antibodies against SARS-CoV-2. Risk factor analysis showed that the largest COVID-19 wave in Guatemala did not increase dog exposure to SARS-CoV-2. However, dogs with outdoor access had higher odds of infection compared to indoors-only dogs. Public health interventions should provide education regarding pet roaming practices to mitigate the spread of zoonotic diseases in rural areas.
ano.nymous@ccsd.cnrs.fr.invalid (Francisco Ferreira) 03 Mar 2026
https://hal.inrae.fr/hal-05535374v1
