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[hal-05169531] Assessment of ex vivo antimalarial drug efficacy in African Plasmodium falciparum parasite isolates, 2016–2023: a genotype–phenotype association study
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Jason Rosado) 18 Jul 2025
https://univ-angers.hal.science/hal-05169531v1
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[hal-05194870] Mass mortality events in the sub-Antarctic Indian Ocean caused by long-distance circumpolar spread of highly pathogenic avian influenza H5N1 clade 2.3.4.4b
Since 2020, the outbreak of highly pathogenic avian influenza (HPAI) virus clade 2.3.4.4b has turned into the largest documented panzootic to date, reaching the sub-Antarctic region and Antarctica via the tip of South America in 2023. Here, we describe its recent arrival into the Indian Ocean sub-Antarctic archipelagos of Crozet and Kerguelen, where we first detected the virus in October 2024 in dead southern elephant seals, king penguins, gentoo penguins, brown skuas and kelp gulls. While the panzootic is ongoing, it has already caused unprecedented and alarming mortalities of southern elephant seals. We collected brain swabs from various seal and bird carcasses, subsequently isolated the virus and obtained 25 novel HPAI H5N1 clade 2.3.4.4b sequences. Our phylogenetic and phylogeographic analyses show that there have been independent introductions of the virus to Crozet and Kerguelen, from the distant South Georgia Islands in the Southern Atlantic, and not from the more nearby coasts of South Africa. Our results point to a year-long gap in genomic surveillance in the south polar region, obscuring how HPAI H5N1 clade 2.3.4.4b is spreading in the sub-Antarctic and illustrating the difficulties in tracking pathogen dispersal in the region. Locally, our phylogenetic analyses show that the virus is transmitted between different species. Moreover, our serological analyses show that some southern elephant seal pups had mounted an anti-H5 antibody response. With the spread to Crozet and Kerguelen, HPAI H5N1 2.3.4.4b is moving ever closer to Australia and New Zealand, which currently remain free from infections with this strain, and represents a major threat to the sub-Antarctic wildlife. Our results provide key elements to enable stakeholders to anticipate the arrival and spread of the virus in remote areas of critical wildlife conservation concerns.
ano.nymous@ccsd.cnrs.fr.invalid (Augustin Clessin) 31 Jul 2025
https://hal.science/hal-05194870v1
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[hal-05186681] Le monde animal et la musique : quand le concept « one health, one welfare » rencontre la musique
Les zoonoses, maladies transmises entre animaux et humains, représentent aujourd’hui 75 % des maladies émergentes répertoriées chez l’humain. Des peintures rupestres au ménétrier meneur de loups en passant par les animaux cornemuseux du Moyen-Âge, il existe de nombreuses représentations anciennes d’animaux musiciens. Par ailleurs, la nature a toujours inspiré les musiciens et parmi les éléments, l’eau tient une place de choix. Si le fait d’associer la musique aux sciences peut paraître assez difficile de prime abord, de nombreux exemples montrent que des parallèles existent, avec des approches parfois transdisciplinaires. Jusqu’au milieu du 20e siècle, la plupart des musiques inspirées par la science étaient liées à la physique et aux mathématiques. Les santés humaine, animale et environnementale sont interconnectées, et regroupées et regroupées sous le terme "One Health". Les relations entre l'humain et l'animal sont un thème récurrent dans le monde de la musique. Avec les avancées spectaculaires de la biologie, en particulier depuis la découverte de la structure de l’ADN, la biologie est à son tour devenue source d’inspiration. Plusieurs projets récents visent à combiner résultats scientifiques et approches artistiques : il peut s’agir de spectacles, de musiques générées à partir de résultats scientifiques. En raison des défis majeurs associés au déploiement de cette approche One Health, les auteurs ont cherché à étudier dans quelle mesure la musique peut permettre de favoriser les approches transdisciplinaires, de changer le regard des scientifiques et des citoyens, de stimuler la recherche de sens autour des initiatives One Health.
ano.nymous@ccsd.cnrs.fr.invalid (Claire Ponsart) 25 Jul 2025
https://hal.science/hal-05186681v1
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[hal-05154805] Interaction dynamics of B. afzelii and TBEV in C3H mice: insights into immune response
Ticks are important vectors responsible for transmitting a wide range of diseases that have significant impacts on both human and animal health. In Europe, the Ixodes tick is especially remarkable for its ability to spread pathogens such as Borrelia, the bacterium that causes Lyme disease, and the tick-borne encephalitis virus, which can lead to serious neurological infections. Building on the results of our previous research involving co-infection with Borrelia afzelii and TBEV in C3H mice, this study aimed to further investigate the interactions between these two pathogens, focusing on the timing of infection and examining mRNA cytokine levels in the brain and spleen of both single- and co-infected mice and their possible link to the clinical outcome. The results revealed that the timing of infection significantly influenced the immune response, highlighting the complex interactions between B. afzelii and TBEV. B. afzelii infection can influence TBEV dynamics, either amplifying or suppressing its effects depending on the timing of infection. In addition, this study helps to better understand how the immune system reacts when both TBEV and B. afzelii infect a host under different conditions. It sheds light on how these pathogens interact and affect disease progression.
ano.nymous@ccsd.cnrs.fr.invalid (Stefania Porcelli) 09 Jul 2025
https://hal.science/hal-05154805v1
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[hal-05091905] Risque zoonotique, voire épidémique et pandémique associé aux virus influenza aviaires.
La crainte d’une pandémie de « grippe aviaire », causée par des virus Influenza issus d’oiseaux, devient de plus en plus présente, même si les cas humains restent sporadiques en l’absence de transmission interhumaine détectée à ce jour et pour beaucoup d’entre eux bénins. Elle est notamment alimentée par la diffusion intercontinentale des virus en cause, qui tous appartiennent au clade 2.3.4.4b, ainsi que par la notification de plusieurs dizaines de cas humains aux USA depuis mars 2024 qui, lorsque la source d’infection est identifiée, sont survenus soit à partir de volailles domestiques, soit, de façon beaucoup plus inattendue, à partir de bovins. En parallèle, un nombre croissant de mammifères de différentes espèces sont atteints de formes graves. L’OMS a fait état du caractère préoccupant de la situation, même si le risque reste à ce jour considéré comme très faible pour la population générale. Pour éclairer la situation présente et tenter d’estimer le risque épidémique voire pandémique, il est utile de se pencher sur plusieurs éléments : - L’historique de la découverte du caractère zoonotique de virus Influenza aviaires, étroitement associée au lignage Gs/GD (ancêtre du clade 2.3.4.4b) : ce lignage a émergé en 1996 en Chine mais son potentiel zoonotique a été révélé en 1997 à Hong Kong en même temps que l’extrême virulence de ce virus pour les volailles domestiques (virus IAHP pour Influenza hautement pathogène), puis a réémergé en 2003 au Vietnam, conduisant à la formalisation du concept de santé globale (One Health), - Les circonstances et la temporalité de la genèse de clades successifs, aboutissant in fine à l’émergence du clade 2.3.4.4b ainsi qu’à sa propagation intercontinentale, d’une ampleur jamais décrite jusqu’alors pour un virus Influenza aviaire, et à sa diffusion chez de nombreuses espèces d’oiseaux et de mammifères, avec des conséquences très graves cliniquement et écologiquement pour certaines d’entre elles. Il est important de noter aussi la situation aux USA, avec notamment l’atteinte de bovins laitiers et d’êtres humains, - les facteurs adaptatifs qui pourraient être à l’œuvre. Tous ces éléments confirment la nécessité d’utiliser une approche centrée sur le concept One Health pour enrayer ou a minima limiter les risques pour les espèces sensibles, dont l’espèce humaine.
ano.nymous@ccsd.cnrs.fr.invalid (Nadia Haddad) 01 Jun 2025
https://hal.science/hal-05091905v1
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[hal-05159491] Cryptosporidiose : quoi de neuf ?
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ano.nymous@ccsd.cnrs.fr.invalid (Karim Adjou) 12 Jul 2025
https://hal.inrae.fr/hal-05159491v1
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[hal-05128804] Contrasting temporal patterns and associations in Hyalomma marginatum microbial communities: key insights for the development of novel tick and tick-borne diseases control tools
Background: Hyalomma marginatum is an invasive tick species in southern mainland France that can carry several pathogens of human and animal interest. Because the tick microbiota represents a major factor that can potentially modulate the pathogen acquisition and transmission and might become a new control tool against ticks and tick-borne diseases, it is more than essential to identify the composition of the H. marginatum microbiota, its temporal dynamics and interactions (statistical association) between members of the tick microbiota. Methods: From monthly tick samplings performed in the same site between February to September 2022, 281 adult ticks H. marginatum were collected from horses. The microbiota composition was characterised using a high throughput sequencing approach. Different statistical analyses allowed us to assess the influence of several factors (month, season, tick sex) on the H. marginatum microbial communities and reveal potential interactions among members of these communities. Results: Apart of known obligate endosymbionts Francisella and Midichloria , and the hypothesised facultative endosymbiont ( Rickettsia ) that dominated the microbiota of H. marginatum , we detected Staphylococcus , Corynebacterium , Williamsia and Mycobacterium , usually described as commensal and/or environmental bacteria. The microbiota composition and bacterial networks differed between males and females, with males being more diverse and composed of more environmental bacteria. We reported several temporal shifts for both males and females into the microbiota composition and bacterial networks. The temporal shifts observed for females were more chaotic in terms of movements among nodes, compared to the male microbial communities that exhibited a more organised and stable dynamics. Conclusions: The influence of tick sex and time on the holobiont H. marginatum underlines the importance of the scale at which the study is conducted. Highlights Obligate endosymbionts dominate the Hyalomma marginatum microbiota Environnemental bacteria are abundant in Hyalomma marginatum microbiota Both the bacterial composition and associations differed according to the tick sex Both the bacterial composition and associations were marked by many temporal shifts for both males and females Keystone taxa in tick microbiota were highly variable from one month to another
ano.nymous@ccsd.cnrs.fr.invalid (Joly-Kukla Charlotte) 25 Jun 2025
https://hal.science/hal-05128804v1
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[hal-05159498] Cryptosporidium parvum et microbiote intestinal
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ano.nymous@ccsd.cnrs.fr.invalid (Karim Adjou) 12 Jul 2025
https://hal.inrae.fr/hal-05159498v1
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[hal-05142231] Differential Impact of Simultaneous or Sequential Coinfections With Borrelia afzelii and Tick‐Borne Encephalitis Virus on the Ixodes ricinus Microbiota
Ticks, particularly Ixodes ricinus , are significant vectors of pathogens such as Borrelia spp. and tick‐borne encephalitis virus (TBEV), which cause Lyme borreliosis (LB) and tick‐borne encephalitis (TBE), respectively. Understanding how these pathogens interact within the tick microbiome is essential for developing vector control strategies. This study investigates the impact of Borrelia afzelii and TBEV, as well as their coinfection, on the microbiota composition and structure of I. ricinus nymphs. Using a network‐based approach, we analyzed the microbial communities of ticks exposed to infected or coinfected mice. DNA extracted from newly molted nymphs was sequenced for the bacterial 16S rRNA gene, and microbial diversity metrics (alpha and beta diversity) were calculated. Our results showed that TBEV infection increased microbiome diversity compared to the uninfected and Borrelia groups. Co‐occurrence network analyses revealed that while microbial structures remained consistent across conditions, TBEV‐infected networks exhibited higher robustness to perturbations, indicating a stabilizing effect on the tick microbiome. Furthermore, the hierarchical position and associations of Borrelia varied significantly depending on the infection scenario, highlighting its adaptive role within the tick microbiota. The study demonstrates that pathogen presence alters tick microbial dynamics, with TBEV enhancing stability, suggesting virus‐mediated modifications of the microbiome. These findings advance our understanding of pathogen–tick–microbiome interactions and provide insights into the ecological mechanisms underlying pathogen coexistence within ticks. This research underscores the importance of microbial networks in ticks and offers new perspectives for targeted approaches in managing tick‐borne diseases.
ano.nymous@ccsd.cnrs.fr.invalid (Apolline Maitre) 03 Jul 2025
https://hal.science/hal-05142231v1
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[hal-05144889] Les collections et les moucherons du genre Culicoides (Diptera : Ceratopogonidae)
Les moucherons du genre Culicoides sont de petits diptères piqueurs de 1 à 4 mm. Seules les femelles sont hématophages et certaines espèces sont très agressives. Les culicoïdes sont responsables de la transmission de nombreux agents pathogènes aux Mammifères, y compris les humains mais aussi les animaux domestiques et sauvages, et Oiseaux. Actuellement près de 1400 espèces sont décrites à travers le Monde. La classification des espèces est presque entièrement phénétique (basé sur la similarité globale). Le développement de la biologie moléculaire notamment le « barcoding » du Cytochrome Oxidase I (COI) ne permet pas de résoudre toutes les questions de classification des culicoïdes. Ceci est d’autant plus vrai quand des espèces décrites ne sont pas retrouvées dans les collectes récentes. Un des moyens est le recours aux spécimens de collections, en utilisant notamment la morphométrie géométrie. Nous présentons ici au travers de quelques exemples, comment l’utilisation des collections peut aider les taxonomistes dans l’identification des espèces.
ano.nymous@ccsd.cnrs.fr.invalid (Leila Hadj-Henni) 04 Jul 2025
https://hal.science/hal-05144889v1
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[hal-05173445] In silico and in vitro assessments of thio-linked pyrimidine-based compounds against Leishmania donovani
Caused by Leishmania parasites, leishmaniases are a group of pathologies acknowledged by the World Health Organization as neglected tropical diseases. Current therapies for treating these infections count on a limited arsenal of drugs with several downsides that restrict their use, namely the development of drug resistance. Innovative medicines with improved efficacy, safety, and a lower tendence for resistance development are imperatively needed.1 Trypanothione reductase (TR) critical function in sustaining the parasite's redox machinery, converting the disulfide bond of trypanothione disulfide (TS2) into reduced trypanothione T(SH)2, makes it a promising biomolecular target in the search for novel antileishmanial compounds. This di-thiol is crucial for scavenging reactive species for Leishmania2,3, offering a potential avenue for drug development. Furthermore, TR offers several advantages, highlighting its structural resemblance to all Trypanosomatidae parasites and its absence in the mammalian host.4 In the search for improved antileishmanial options, a study discovered the potential of aryl sulfides in deactivating TR.3,5 Based on these findings, we unveil the synthesis of a library of novel thio-linked pyrimidine-based compounds applying the Buchwald–Hartwig reaction that leads to the formation of different products by changing the reaction time. Our findings from the computational studies show that all compounds interact with the residues from the NADPH-binding site, thus limiting the interaction between TR and its cofactor, NADPH. We also provide the results of all compounds' in vitro antileishmanial activity against L. donovani axenic and intramacrophage amastigotes, and their cytotoxicity against Raw 264.7 cells. Compounds IC69 and IC90 were the most effective against both forms of Leishmania, exhibiting IC50 values lower than the control, miltefosine (Figure 1).
ano.nymous@ccsd.cnrs.fr.invalid (Ines Carreira Costa) 28 Jul 2025
https://hal.science/hal-05173445v1
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[hal-05170274] Detection of the zoonotic nematode Angiostrongylus cantonensis in Pacific crustaceans by real-time PCR
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Thomas Guilmin) 18 Jul 2025
https://hal.science/hal-05170274v1
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[hal-05170280] Prévalence et facteurs de risques d’infestation des jeunes équidés normands par le nématode Parascaris spp.
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Kenza Bourrier) 18 Jul 2025
https://hal.science/hal-05170280v1
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[hal-05159470] Molecular and Epidemiological Investigation of Cryptosporidium Infection in Goat Population from Bouira Province, Algeria
Cryptosporidiosis is a gastrointestinal disease affecting terrestrial and aquatic vertebrates worldwide. This study investigated molecularly and microscopically the prevalence and the diversity of Cryptosporidium spp. in goats across the Bouira communes, Algeria. A total of 559 fecal samples were collected from 70 farms, representing 16.6% of the regional goat population. Samples were analyzed using microscopy (modified Ziehl-Neelsen staining) and molecular methods (i.e., qPCR and nested PCR targeting the 18S rRNA gene, followed by sequencing). Microscopy detected Cryptosporidium in 6.1% of samples, while qPCR revealed a significantly higher prevalence of 13.6% (p < 0.00001), confirming the superior sensitivity of molecular diagnostics. Spatial analysis identified significant clustering (Moran's I = 0.330, p = 0.0003), with communes-level prevalence ranging from 6.7% to 45.7%. Infection rates correlated positively with humidity and rainfall but negatively with temperature. Phylogenetic analysis confirmed Cryptosporidium xiaoi as the sole species circulating, showing 100% genetic similarity to global caprine isolates. Despite C. xiaoi's host adaptation, a GenBank review highlighted six other zoonotic species infecting goats worldwide, underscoring potential cross-species transmission risks. The study emphasizes the need for PCR-based surveillance to assess true prevalence and zoonotic threats, while climatic findings support targeted interventions in high-risk areas.
ano.nymous@ccsd.cnrs.fr.invalid (Samia Bedjaoui) 12 Jul 2025
https://hal.inrae.fr/hal-05159470v1
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[hal-05099569] Les explants intestinaux félins : modèle d’étude des interactions de Toxoplasma gondii avec la réponse immunitaire de la muqueuse de son hôte définitif.
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Julie Rouzet) 05 Jun 2025
https://hal.science/hal-05099569v1
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[hal-05146891] Les parasites des viandes : état des connaissances en France
Les parasites des viandes : état des connaissances en France Bruno Polack, Isabelle Vallée et tous les membres du LNR « Parasites zoonotiques transmis par les aliments » Les parasites présentent parfois des cycles complexes faisant intervenir plusieurs hôtes ou une étape environnementale. Nos aliments peuvent ainsi être contaminés s’ils proviennent d’un animal hôte infesté (viandes, abats, charcuteries, poissons), ou encore par contamination de surface des végétaux par des œufs/oocystes. Le spectre des parasites concernés est large et nous nous intéresserons aux parasites zoonotiques présents dans les matrices carnées en France. Certains d'entre eux font l'objet d'une inspection réglementaire à l'abattoir par palpation ou contrôle visuel de lésions (myosite à Sarcocystis spp., kystes de Sarcocystis spp. de grande taille, cysticerques ou kyste hydatique), voire d'une analyse microscopique en laboratoire (Trichinella spp.), mais pour d'autres parasites, l'évaluation de la (séro)-prévalence se fait lors de plans de surveillance (Toxoplasma gondii). Enfin, quelques espèces parasitaires ont été découvertes lors d'analyses de recherche de larves de trichine (Alaria alata, Toxocara spp.). Nous dresserons un bilan des parasites zoonotiques identifiés et pour lesquels des données sont disponibles en France.
ano.nymous@ccsd.cnrs.fr.invalid (Bruno Polack) 07 Jul 2025
https://enva.hal.science/hal-05146891v1
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[hal-05170278] L’IA valorise l’intelligence (naturelle) de nos anciens
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Frédérick Gay) 18 Jul 2025
https://hal.science/hal-05170278v1
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[hal-05109757] Etude de prévalence de T. gondii chez les mammifères marins en France et génotypage
Toxoplasma gondii est un protozoaire intracellulaire strict, capable d’infecter une grande variété d’hôtes d’intermédiaires à sang chaud : mammifères et oiseaux. Les oocystes émis dans les fèces des chats et autres félidés (hôtes définitifs) sont résistants dans l'environnement, notamment dans l'eau de mer. Ils peuvent rester infectieux pendant plusieurs mois, et constituer une source de contamination pour les mammifères marins. De nombreuses études à travers le monde ont permis de mettre en lumière la présence de ce parasite, avec une prévalence globale chez les mammifères marins sauvages de 22.4% (Li et al., 2022), arguant d’une contamination du milieu marin notable, avec un impact considérable sur la santé des écosystèmes pouvant présenter un risque pour la santé humaine. En France, les données concernant la prévalence de T. gondii chez les mammifères marins demeurent limitées. L’objectif de notre étude est d’évaluer la prévalence de T. gondii chez des mammifères marins échoués entre 2010 et 2023 sur les côtes métropolitaines françaises, et de caractériser la diversité génétique des souches. Un total de 60 muscles de mammifères marins échoués sur les côtes de la Méditerranée, de l'Atlantique et de la Manche a été prélevé, comprenant 43 dauphins communs (Delphinus delphis), 6 grands dauphins (Tursiops truncatus), 5 marsouins communs (Phocoena phocoena), 3 dauphins bleu et blanc (Stenella coeruleoalba), 1 globicéphale noir (Globicephala melas), 1 phoque gris (Halichoerus grypus), 1 baleine à cuvier (Ziphius cavirostris). Quatre-vingt-quinze pourcent (57/60) des spécimens étudiés provenaient de la côte Atlantique dont 74 % (42/57) appartenaient à l’espèce dauphin commun (Delphinus delphis). Après collecte des fluides musculaires, un test d’agglutination directe haute sensibilité (ADHS) a été réalisé sur les 60 échantillons. Les résultats obtenus (seuil ≥1/6) suggèrent une séroprévalence globale de 56,7 % (34/60) [IC 95% : 0.442, 0.692]. La séroprévalence pour les dauphins communs (Delphinus delphis) était de 69.8 % (30/43) [IC 95% : 0,5613 ; 0,8341]. Deux marsouins communs (Phocoena phocoena), et 2 grands dauphins (Tursiops truncatus) étaient séropositifs. Toutes les autres espèces étaient séronégatives. Une PCR quantitative ciblant la séquence répétée 529 bp et le gène B1 a validé la présence de l’infection à T.gondii chez 8 dauphins communs. Trois isolats ont pu être génotypés à partir de l’ADN extrait mettant en évidence 3 nouveaux génotypes de type II. L’un proche d’un génotype trouvé chez 3 patients (français) et d’un porc français, à 2 marqueurs de différence. Un autre se rapprochant de 2 souches de patients français, avec une variation sur un seul marqueur. Le dernier type II se rapproche le plus d’une souche humaine isolée à Nantes et d’une souche animale originaire de Turquie, avec 3 marqueurs différents. Un quatrième isolat génotypé partiellement a mis en évidence une souche atypique. La séroprévalence élevée de T. gondii chez les mammifères marins, en particulier chez le dauphin commun suggère une forte contamination du milieu marin par les oocystes. L’identification de trois nouveaux génotypes de types II témoigne de la diversité génétique du parasite et de sa circulation entre le milieu terrestre et marin, notamment via le lessivage des sols souillés par les matières fécales de chats contaminés. La mise en évidence d’un génotype incomplet semblant atypique pose la question d’une possible introduction sur nos côtes de souches atypiques exotiques qui pourraient être en lien avec les migrations de ces mammifères marins. Cette transmission suppose un risque pour la santé publique, en particulier par consommation de produits de la mer potentiellement contaminés (Robertson, 2007). Les résultats concernant certaines espèces doivent être interprétés avec prudence en raison du faible nombre d’échantillons, d’où la nécessité d’une étude plus large pour mieux comprendre les facteurs de risque et les implications écologiques.
ano.nymous@ccsd.cnrs.fr.invalid (Sandra Thoumire) 12 Jun 2025
https://hal.science/hal-05109757v1
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[hal-05173348] In silico and in vitro assessments of thio-linked pyrimidine-based compounds against Leishmania donovani
Caused by Leishmania parasites, leishmaniases are a group of pathologies acknowledged by the World Health Organization as neglected tropical diseases. Current therapies for treating these infections count on a limited arsenal of drugs with several downsides that restrict their use, namely the development of drug resistance. Innovative medicines with improved efficacy, safety, and a lower tendence for resistance development are imperatively needed.1 Trypanothione reductase (TR) critical function in sustaining the parasite's redox machinery, converting the disulfide bond of trypanothione disulfide (TS2) into reduced trypanothione T(SH)2, makes it a promising biomolecular target in the search for novel antileishmanial compounds. This di-thiol is crucial for scavenging reactive species for Leishmania2,3, offering a potential avenue for drug development. Furthermore, TR offers several advantages, highlighting its structural resemblance to all Trypanosomatidae parasites and its absence in the mammalian host.4 In the search for improved antileishmanial options, a study discovered the potential of aryl sulfides in deactivating TR.3,5 Based on these findings, we unveil the synthesis of a library of novel thio-linked pyrimidine-based compounds applying the Buchwald–Hartwig reaction that leads to the formation of different products by changing the reaction time. Our findings from the computational studies show that all compounds interact with the residues from the NADPH-binding site, thus limiting the interaction between TR and its cofactor, NADPH. We also provide the results of all compounds' in vitro antileishmanial activity against L. donovani axenic and intramacrophage amastigotes, and their cytotoxicity against Raw 264.7 cells. Compounds IC69 and IC90 were the most effective against both forms of Leishmania, exhibiting IC50 values lower than the control, miltefosine (Figure 1).
ano.nymous@ccsd.cnrs.fr.invalid (Sandrine Cojean) 21 Jul 2025
https://hal.science/hal-05173348v1
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[hal-05165026] In copula depuis 1998 : description d’un couple d’Ixodes (Afrixodes)
Très peu étudié, le sous-genre Afrixodes, inféodé à l’Afrique tropicale, appartient au genre de tiques dures Ixodes. Ce sous genre comprend 62 espèces, représentées actuellement uniquement en Afrique (sauf 2 espèces d’Inde), dont 9 espèces endémiques de l’île de Madagascar. Or, la taxonomie de la grande majorité des espèces de ce sous genre Afrixodes reste largement à préciser. Il manque la description des mâles chez 47% des espèces de ce sous-genre, 69% pour les nymphes et 78% pour les larves. Seulement 14 espèces d’Afrixodes disposent d’au moins une séquence déposée dans Genbank (dont Cox1 & 16S). Tout ce manque d’information rend l’identification des spécimens très compliquée, d’autant que les planches de description morphologique peuvent varier d’un auteur à l’autre. C’est la problématique rencontrée ici avec 2 spécimens, mâle et femelle, conservés en alcool depuis 1998, collectés in copula sur une crocidure au Gabon. Par l’originalité de la découverte de ces spécimens, une analyse préliminaire a été réalisée par comparaison des caractères morphologiques disponibles dans les descriptions existantes d’Ixodes (Afrixodes) mais aussi par séquençage des gènes 16S et Cox1, afin d'identifier les spécimens. Malgré le peu de donnée génétique disponible sur ces espèces, le 16S nous permet de confirmer que les 2 spécimens appartiennent bien à la même espèce, tandis que le Cox1 nous les rapproche d’Ixodes rasus Neumann 1899. Faute de certaines descriptions de mâles et au vu de l’assignation par le 16S, nous ne pouvons pour le moment pas confirmer leur appartenance à cette espèce. Néanmoins, il existe un groupe d’espèce au sein du sous-genre Afrixodes, le groupe rasus, comprenant 5 espèces (I. rasus, I. pseudorasus Arthur 1957, I. muniensis Arthur et Burrow 1957, I. procaviae Arthur et Burrow 1957, I. thomasae Arthur et Burrow 1957) dont pourraient faire partie ces spécimens. De plus profondes investigations seront menées par la suite grâce au séquençage NGS.
ano.nymous@ccsd.cnrs.fr.invalid (Camille Lorang) 16 Jul 2025
https://hal.science/hal-05165026v1
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[hal-05165009] Extraction d’ADN non destructive : une méthode pour garder la forme !
Afin d’améliorer la robustesse de l’identification des espèces, la taxonomie intégrative combine caractérisation génétique et morphologique. Il est donc indispensable de conserver l’intégrité corporelle des spécimens d’étude. Cependant, pour avoir accès aux données moléculaires, il est nécessaire de sacrifier le spécimen, ou une partie. Afin de pallier à ce problème, la méthode d’extraction d’ADN de façon non-destructive commence à trouver ses marques au sein des équipes de taxonomistes, et notamment pour notre étude des tiques dures. Comme l’a dit un autre Arachnide : « Un grand pouvoir implique de grandes responsabilités ». C’est le leitmotiv principal de cette méthode mise au point ici, exposer la force de l’extraction non destructive de l’ADN chez les tiques, pour la taxonomie intégrative mais aussi pour le diagnostic de pathogènes. Et tout cela serait possible en préservant leur morphologie, afin de les conserver en collection en Muséum pour de futures références. Les maladies transmises par les tiques sont un véritable enjeu sanitaire et les outils de diagnostic ont besoin d’informations biomoléculaires sur ces microorganismes hébergés, et de part cette méthode, nous pouvons avoir accès à cette information chez les tiques. Ainsi, par cette méthode, nous identifions à la fois les espèces de tiques et les agents pathogènes hébergés, tout en préservant la morphologie de celles-ci.
ano.nymous@ccsd.cnrs.fr.invalid (Camille Lorang) 16 Jul 2025
https://hal.science/hal-05165009v1
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[hal-05132420] Deep sequencing of 16 Ixodes ricinus ticks unveils insights into their interactions with endosymbionts
Ixodes ricinus ticks act as vectors for numerous pathogens that present substantial health threats. Additionally, they harbor vertically transmitted symbionts, some of which have been linked to diseases. The difficulty of isolating and cultivating these symbionts has hampered our understanding of their biological role, their potential to cause disease, and their modes of transmission. To expand our understanding of the tick symbiont Midichloria mitochondrii and Rickettsia helvetica , which has been linked to disease in humans, we utilized deep sequencing on 16 individual adult female ticks collected from coastal dune and forested areas in the Netherlands. By employing a combination of second- and third-generation sequencing techniques, we successfully reconstructed the complete genomes of M. mitochondrii from 11 individuals, R. helvetica from eight individuals, and the mitochondrial genome from all ticks. Additionally, we visualized the location of R. helvetica in tick organs and constructed genome-scale metabolic models (GEMs) of both symbionts to study their environmental dependencies. Our analysis revealed a strong cophylogeny between M. mitochondrii and mitochondrial genomes, suggesting frequent maternal transmission. In contrast, the absence of cophylogeny between R. helvetica and the mitochondrial genomes, coupled with its presence in the receptaculum seminis of I. ricinus females, raises the possibility of paternal transmission of R. helvetica . Notably, the genetic diversity of R. helvetica was found to be very low, except for the rickA virulence gene, where the presence of up to 13 insertions of a 33 nt-long repeat led to significant variability. However, this variation could not account for the differences in infection prevalence observed across eight distinct locations in the Netherlands. By employing deep sequencing, it becomes feasible to extract complete genomes and genetic data of symbionts directly from their host organisms. This methodology serves as a robust means to gain fresh insights into their interactions. Our observations, which suggest paternal transmission of R. helvetica , a relatively unexplored mode of transmission in ticks, require validation through experimental investigations. The genetic variations identified in the rickA virulence gene of R. helvetica have the potential to influence the infectivity and transmission dynamics of R. helvetica . IMPORTANCE Ticks are vectors of numerous human pathogens; however, the microbial interactions within ticks and the mechanisms governing pathogen transmission remain poorly understood. This study uses deep sequencing of individual Ixodes ricinus to reconstruct high-quality genomes of endosymbionts and the mitochondrion of the tick, revealing previously undetected microbial dynamics. Notably, we recovered low-abundance Rickettsia and Midichloria genomes from single ticks and present evidence that suggests paternal transmission of R. helvetica . These findings offer novel insights into the ecology and evolution of tick-associated microbes and have implications for understanding the origins and spread of tick-borne diseases.
ano.nymous@ccsd.cnrs.fr.invalid (Paulina Lesiczka) 21 Jul 2025
https://hal.inrae.fr/hal-05132420v1
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[hal-05132549] Insight Into the Tick Neurosecretory System
Although the nervous systems of ticks and insects are thought to have evolved convergently, the organization and functional architecture of the tick neurosecretory system, particularly the anatomical localization of neuropeptide release sites, remain largely uncharacterized. In the present study, we used immunohistochemical labeling with antibodies targeting various neuropeptide classes to identify previously unreported lateral and medial clusters of peptidergic neurosecretory cells (NSCs) within the anterior protocerebrum of the synganglion in Ixodes ricinus, the primary European vector of Lyme disease. These NSCs give rise to dense axonal projections forming a superficial network on the dorso-lateral synganglionic surface, in addition to extending neurites into nearly all internal lobes. Ultrastructural analyses via immunogold transmission electron microscopy demonstrated that axon terminals located on the synganglion surface terminate within the dorsal perineurium and secrete neuropeptides into an acellular neurilemma layer directly adjacent to the haemolymph compartment. Furthermore, both lateral and medial NSC terminals exhibited differential expression of muscarinic acetylcholine receptors (mAChRs), with type A and B subtypes detected, respectively, indicating cholinergic sensitivity. Physiological manipulation via microinjection of 100 nL of water into the haemocoel of unfed females resulted in a marked increase in neuropeptide-associated fluorescence at the terminal regions of dorsal surface axons, consistent with enhanced synthesis and axonal transport of neuropeptides. Conversely, administration of 10 µM acetylcholine (ACh) significantly attenuated the fluorescent signal, suggesting ACh-induced neuropeptide exocytosis. We propose that the observed fluorescence enhancement reflects neuropeptide accumulation in response to changes in haemolymph volume, whereas ACh-mediated signal reduction corresponds to stimulus-evoked hormonal release. Based on these findings, we propose a novel model in which acetylcholine functions as a hormonal trigger for peptide release from NSCs in ticks.
ano.nymous@ccsd.cnrs.fr.invalid (Ladislav Šimo) 27 Jun 2025
https://hal.inrae.fr/hal-05132549v1
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[hal-05149174] Différencier Giardiose et trichomonose et les traiter
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Mohamed Mammeri) 07 Jul 2025
https://hal.science/hal-05149174v1
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[hal-05130126] Molecular detection of Toxoplasma gondii in ready-to-eat salad mixes: multi-country survey using a validated and harmonised standard operating procedure, Europe, 2021 to 2022
Background Most Toxoplasma gondii infections in humans are considered foodborne, but the relative importance of the various routes of infection is largely unknown. Consumption of green produce contaminated with T. gondii oocysts has been identified as a possible source. Aim We aimed to estimate the occurrence and prevalence of T. gondii oocysts in commercially available ready-to-eat (RTE) salad mixes in 10 European countries. Methods A real-time PCR-based method for oocyst detection was developed and optimised by two laboratories and validated in an interlaboratory test. This detection method and a harmonised sampling strategy were applied in a multi-country study. Multivariable logistic regression was used to investigate risk factors for oocyst contamination of RTE salad. Results The real-time PCR method had a detection limit of 10 oocysts per 30 g of salad. We collected 3,329 RTE salad samples (baby leaf and cut leaf mixes) from October 2021 to September 2022. The prevalence of T. gondii oocyst contamination was 4.1% (95% confidence interval (CI): 3.4–4.8%; n = 3,293). In multivariable regression analysis, winter season, sampling and packaging of salad in Northern Europe and production of salad in Western Europe were associated with detection of T. gondii , with no statistically significant differences between salad types. Conclusion We estimated the prevalence of T. gondii oocysts in RTE leafy green salads using a validated and standardised procedure to assess the potential risk for human infection; highlighting the need to address this risk at each critical point of the salad production chain.
ano.nymous@ccsd.cnrs.fr.invalid (Rafael Calero-Bernal) 25 Jul 2025
https://hal.science/hal-05130126v1
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[hal-05173262] Pharmacophore-guided optimization of the hit compound CTN1122 in the design of promising imidazo[1,2- a ]pyrazine derivatives targeting the casein kinase 1 for antileishmanial therapy
Our research group identified CTN1122, an imidazo[1,2-a]pyrazine derivative, as a promising antileishmanial agent targeting intramacrophage amastigotes of Leishmania major and Leishmania donovani. CTN1122 selectively inhibits Leishmania casein kinase 1 (L-CK1.2) with a favorable safety profile. Docking studies based on a homology model highlighted key pharmacophoric elements: a 4-pyridyl group at C3, crucial for hydrogen bonding with leucine 90 in the ATP-binding site, and a 4-fluorophenyl moiety at C2, fitting into a hydrophobic pocket. In order to validate these findings, 14 analogs were synthesized with targeted modifications on the imidazo[1,2-a]pyrazine core structure. Three probed the C8 position, three evaluated the impact of C2 substitution, six assessed the C3 4-pyridyl group, and two combined changes at C8 and C3. The study confirmed the critical role of C2 and C3 substituents, as their absence significantly reduced L-CK1.2 inhibition and antileishmanial activity. Additionally, the nitrogen's position within the pyridine ring at C3 proved essential: compound 23, with a meta-pyridyl group, was inactive. Notably, compound 30 exhibited the highest antileishmanial in vitro potency (IC50 = 0.20 μM for L. major; 0.16 μM for L. donovani) alongside enhanced L-CK1.2 inhibition (IC50 = 0.384 μM), with no significant mammalian cytotoxicity.
ano.nymous@ccsd.cnrs.fr.invalid (Lhana Tisseur) 21 Jul 2025
https://hal.science/hal-05173262v1
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[hal-05099591] Feline intestinal explants to study interactions of Toxoplasma gondii with the mucosal immune response of its definitive host
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Julie Rouzet) 05 Jun 2025
https://hal.science/hal-05099591v1
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[hal-05172503] Prévalence et facteurs de risques d’infestation des jeunes équidés normands par le nématode Parascaris spp
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ano.nymous@ccsd.cnrs.fr.invalid (Kenza Bourrier) 21 Jul 2025
https://hal.science/hal-05172503v1
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[hal-05131886] Culicoides insignis in Ecuador: Molecular identification of blood meals and detection of bluetongue virus
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ano.nymous@ccsd.cnrs.fr.invalid (Juan Mosquera) 25 Jul 2025
https://hal.science/hal-05131886v1
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[hal-05149237] Re-sensitization of antimony-resistant Leishmania by highly potent SbV-porphyrin through the involvement of ERG6-coding gene
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ano.nymous@ccsd.cnrs.fr.invalid (Ellen Gonçalves De Oliveira) 07 Jul 2025
https://hal.science/hal-05149237v1
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[hal-05130134] Systematic review of zoonotic parasites in game in Europe
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ano.nymous@ccsd.cnrs.fr.invalid (Helga Waap) 25 Jun 2025
https://hal.science/hal-05130134v1
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[hal-05168360] Quels parasites digestifs infestent les jeunes équidés normands ?
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ano.nymous@ccsd.cnrs.fr.invalid (Kenza Bourier) 17 Jul 2025
https://hal.science/hal-05168360v1
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[hal-05168357] Caractérisation des populations de Parascaris spp. en France chez les poulains : Prévalence, résistance et phylogénie
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Kenza Bourrier) 17 Jul 2025
https://hal.science/hal-05168357v1
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[hal-05159481] Cryptosporidiose et giardiose : où en est la recherche ?
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ano.nymous@ccsd.cnrs.fr.invalid (Karim Adjou) 12 Jul 2025
https://hal.inrae.fr/hal-05159481v1
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[hal-05096204] Validation of a High-Throughput Microfluidic Real-Time PCR for the Detection of Vector-Borne Agents in Wild Birds from the Brazilian Pantanal
Despite numerous studies on haemosporidians in wild birds from Brazil, the presence of other vector-borne agents (VBA) such as Anaplasma spp., Bartonella spp., and Onchocercidae filariids in avian hosts remains largely unknown. The low occurrence of these VBAs might be due to the low sensitivity of traditional molecular techniques. The microfluidic real-time PCR assay, known for its high sensitivity, has emerged as a promising method to detect and study the occurrence and diversity of VBAs in both arthropod vectors and vertebrate hosts. To validate previously and standardize newly designed microfluidic real-time PCR protocols, selected positive avian blood DNA samples for Anaplasma spp., Bartonella spp., haemosporidians, and filariids were used. The molecular occurrence rates for the selected VBAs were 18.2% for Anaplasma spp., 0.36% for Bartonella spp., 6.2% for Plasmodium spp., 4.7% for Haemoproteus spp., and 6.5% for Onchocercidae filariids. The Plasmodium spp. cytB sequence detected in a Volatinia jacarina clustered with Plasmodium tejerai, whereas the Haemoproteus spp. cytB sequence detected in a Columbina squamata clustered with Haemoproteus columbae. While Onchocercidae filariid cox-1 sequences were detected in specimens of Ramphocelus carbo, Turdus amaurocalinus and Synallaxis albilora grouped with Aproctella spp., one sequence detected in R. carbo was ancestral to the clade comprising Splendidofilaria spp. and Eufilaria spp. High-throughput microfluidic real-time PCR assay can be used for screening VBAs in avian hosts from South America, but new primers/probe sets should be designed for VBA genotypes present in Brazil.
ano.nymous@ccsd.cnrs.fr.invalid (Amir Salvador Alabí Córdova) 04 Jun 2025
https://hal.science/hal-05096204v1
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[hal-05173401] In silico and in vitro assessments of thio-linked pyrimidine-based compounds against Leishmania donovani
Caused by Leishmania parasites, leishmaniases are a group of pathologies acknowledged by the World Health Organization as neglected tropical diseases. Current therapies for treating these infections count on a limited arsenal of drugs with several downsides that restrict their use, namely the development of drug resistance. Innovative medicines with improved efficacy, safety, and a lower tendence for resistance development are imperatively needed.1 Trypanothione reductase (TR) critical function in sustaining the parasite's redox machinery, converting the disulfide bond of trypanothione disulfide (TS2) into reduced trypanothione T(SH)2, makes it a promising biomolecular target in the search for novel antileishmanial compounds. This di-thiol is crucial for scavenging reactive species for Leishmania2,3, offering a potential avenue for drug development. Furthermore, TR offers several advantages, highlighting its structural resemblance to all Trypanosomatidae parasites and its absence in the mammalian host.4 In the search for improved antileishmanial options, a study discovered the potential of aryl sulfides in deactivating TR.3,5 Based on these findings, we unveil the synthesis of a library of novel thio-linked pyrimidine-based compounds applying the Buchwald–Hartwig reaction that leads to the formation of different products by changing the reaction time. Our findings from the computational studies show that all compounds interact with the residues from the NADPH-binding site, thus limiting the interaction between TR and its cofactor, NADPH. We also provide the results of all compounds' in vitro antileishmanial activity against L. donovani axenic and intramacrophage amastigotes, and their cytotoxicity against Raw 264.7 cells. Compounds IC69 and IC90 were the most effective against both forms of Leishmania, exhibiting IC50 values lower than the control, miltefosine
ano.nymous@ccsd.cnrs.fr.invalid (Sandrine Cojean) 21 Jul 2025
https://hal.science/hal-05173401v1
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[hal-05081557] Effect of a ceruminolytic ear cleaner on clinical, microbiological and ear canal microbiome evolution in canine erythemato‐ceruminous otitis externa associated with proliferation of Malassezia yeasts
Abstract Background Erythemato‐ceruminous otitis externa (ECOE) is commonly associated with Malassezia spp. and microbial imbalance. Hypothesis/Objective To assess the clinical performance of an ear cleaner in dogs suffering from ECOE associated with Malassezia spp. overgrowth and to measure its impact on the microbiota. Animals Thirty privately owned dogs suffering from mild‐to‐moderate ECOE associated with Malassezia spp. overgrowth. Materials and Methods Pruritus score (PS), clinical score (0–3 Otitis Index Score [OTIS3]: based on secretions, erythema, hyperplasia and ulceration) and cytological score (CS) were assessed on Day (D)0, D7, and D14. Sterile ear swabs were used on D0 and D14 to perform fungal culture DNA extraction, and PCR amplification of the 18 ITS and 16S rRNA gene was carried out to evaluate the composition and changes of the otic microbiome. Ears were cleaned with a cerumenolytic ear cleanser daily, every other day, or twice a week depending on the secretion score. Results Fifty‐seven ears (30 dogs) completed the study. PS, OTIS‐3, and CS were significantly decreased at D7 and D14 (−45%, −43%, −60% and −77%, −66%, −76%, respectively; p < 0.0001 Wilcoxon test). Fungal culture was positive ( Malassezia spp. ) in only 34 ears at D0 and was negative in all ears at D14. Mycobiota composition was significantly different before and after treatment with an increase of fungal diversity (Shannon index; p < 0.003 Wilcoxon test) at D14 compared to D0. There was no change in bacterial composition. Conclusions and Clinical Relevance In case of ECOE associated with Malassezia spp. overgrowth, the use of the tested ear cleaner showed a positive impact on the fungal dysbiosis and Malassezia spp. overgrowth.
ano.nymous@ccsd.cnrs.fr.invalid (Amaury Briand) 23 May 2025
https://hal.science/hal-05081557v1
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[hal-05054201] Culicoides species of Palaearctic region in Afrotropical region : comments on two recent publications on Culicoides species present in Ethiopia
Biting midges are key vectors that can transmit different pathogens to mammals and birds. In Ethiopia, two studies showed the diversity of Culicoides species in several districts based on morphological characters. For this, the same identification key was used for Afrotropical and Palaearctic Culicoides fauna. Consequently, results are incomplete and erroneous. It is misleading to state that a universal identification key is available.
ano.nymous@ccsd.cnrs.fr.invalid (Denis Augot) 17 Jul 2025
https://hal.science/hal-05054201v1
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[hal-04994083] Risk factors for tick infestation and equine Piroplasmosis infection among draught horses in France
Equine piroplasmosis, caused by the protozoan parasites Babesia caballi and Theileria equi, is endemic in Europe's Mediterranean basin, creating significant health and economic challenges for the equine sector. With no available vaccine, an eco-epidemiological approach is essential in order to identify and implement effective preventive measures. With this aim in view, we identified risk factors associated with B. caballi and T. equi infections and tick infestation for draught horses in the Auvergne-Rhône-Alpes region of France, known for its high piroplasmosis seroprevalence. During the spring of 2021, blood samples from 146 horses and ticks from both hosts and pastures were collected across 38 farms, then analysed using PCR to determine parasite prevalence. Environmental and meteorological data, along with information on management practices and individual horse characteristics, were collected on-site and from national databases. The results showed significant spatial variability in T. equi and B. caballi prevalence in horses, ranging from 25.7 % [95 % CI: 13.1 -43.6] to 83.7 % [95 % CI: 69.8 -92.2] and from 0 % [95 % CI: 0.0 -26.8] to 26.5 % [95 % CI: 15.4 -41.3], respectively. Among 1046 collected ticks, 3 % carried either a species of Babesia or Theileria and were identified as Dermacentor marginatus, Dermacentor reticulatus or Ixodes ricinus. We showed a stronger link between the environment and tick exposure for T. equi infections, while B. caballi infections were more closely associated with individual horse characteristics and management practices. Key risk factors for tick infestation included environmental conditions (temperature, rainfall, vegetation cover, altitude, etc.) and the presence of wild animals in pastures. These findings provide a valuable foundation on which to develop targeted prevention and control strategies to protect horses in enzootic regions.
ano.nymous@ccsd.cnrs.fr.invalid (Clémence Nadal) 17 Mar 2025
https://hal.science/hal-04994083v1
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[hal-05044684] L'ENCÉPHALITE À TIQUES EN EUROPE ET NOTAMMENT EN FRANCE : UNE MENACE GRANDISSANTE NÉCESSITANT UN RENFORCEMENT DES SYSTÈMES D'ÉPIDÉMIO-SURVEILLANCE ET DES MESURES DE PRÉVENTION
L’encéphalite à tiques (TBE) est une zoonose due à un arbovirus, le TBEV, à transmission essentiellement vectorielle par des tiques du genre Ixodes mais également par la consommation de produits laitiers non pasteurisés de ruminants infectés. Environ 10 000 à 12 000 cas sont déclarés chaque année dans le monde et elle est en pleine expansion en Europe et en France, notamment en raison du changement climatique. En l’absence de traitement étiologique disponible, la prévention constitue une approche essentielle dans la gestion du risque croissant de survenue de cas de TBE en France. Elle se doit désormais de prendre en compte le risque alimentaire récemment mis en lumière en 2020 suite au premier cluster humain d’origine alimentaire en France (Ain, 43 patients atteints). Des solutions envisageables à terme dans les élevages de ruminants, pour gérer le risque alimentaire, permettraient de renforcer les systèmes d’épidémio-surveillance français et européen, encore lacunaires.
ano.nymous@ccsd.cnrs.fr.invalid (Léna Carnet) 12 May 2025
https://hal.science/hal-05044684v2
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[hal-05044485] Diversity of Tick Species and Tick-borne Pathogens Hosted by Urban and Suburban European Hedgehogs (Erinaceus europaeus) in France.
Ticks transmit a variety of pathogens that affect both animal and human health, underscoring the importance of understanding diversity and transmission dynamics. The European hedgehog (Erinaceus europaeus) serves as a host for ticks such as Ixodes hexagonus and Ixodes ricinus, potentially playing a role in the enzootic cycle of tick-borne diseases. This study aimed to evaluate the use of hedgehogs as sentinels for monitoring tick-borne pathogens in urban and suburban areas. A total of 251 hedgehogs were involved in the study, conducted between 2019 and 2021, with 144 examined for ticks and 110 undergoing ear biopsies. Using real-time PCR, multiple pathogens were identified among the hedgehogs, including Borrelia afzelii, Rickettsia asembonensis, and Anaplasma phagocytophilum. Most (96%) ticks collected were I. hexagonus, primarily nymphs and adult females, confirming this species as the main infester of hedgehogs. Carcasses obtained from a wildlife animal hospital provided an accessible source of biological material for this study. The results indicated that hedgehogs could serve as sentinel hosts for the surveillance of Borrelia burgdorferi complex, Rickettsia spp., and A. phagocytophilum in urban and suburban environments. Further research is needed to explore the relationship among hedgehog population densities, tick infestation levels, and the prevalence of tick-borne pathogens. Such studies are essential to determine the contribution of hedgehogs to the enzootic transmission cycle of these pathogens and to evaluate the resultant risks to human health.
ano.nymous@ccsd.cnrs.fr.invalid (Isabelle Defosseux) 23 Apr 2025
https://hal.inrae.fr/hal-05044485v1
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[hal-05057357] Feline intestinal explants to study interactions of Toxoplasma gondii with the mucosal immune response of its definitive host
Toxoplasma gondii is the 3rd most important foodborne parasite identified by the FAO/WHO as a threat to public health. The development of effective vaccines or drugs against toxoplasmosis has largely been hampered by the lack of data on the T. gondii sexual reproductive cycle, which occurs only in felids. We study T. gondii interactions with the feline intestinal microenvironment to decipher local immune responses and understand their impact on the parasite life cycle, to discover new ways to target this clinically important protozoan. We developed a model of feline intestinal explants, which has been previously used to study different intestinal pathologies in various species, but has never been developed in cats. To study the local feline immune response, we used for the first time the RNAscope® technology on intestinal tissue to follow cytokines expression upon different culture conditions and in presence of T. gondii. Culture condition modalities included variation of the duration of the incubation, as well as the atmosphere composition. So far, our work followed the expression of four key Th1/Th2 cytokines: IFN-/IL-12 and IL-4/IL-5. Explant enterocytes can be infected by T. gondii tachyzoites within 24h of infection ex vivo. All four cytokines are expressed in the tissues at the mRNA level, with IL-4 showing the lowest expression. Variation in cytokine expression are observed depending on the length of the incubation, and the presence or the absence of the parasite in the tissues. Moreover, incubation in hyperoxia conditions to extend tissue survival induces variation in both Th1 and Th2 cytokine expression. Quantifications of these observations are currently ongoing. These preliminary results validate the use of intestinal explants and the RNAscope® technology to study T. gondii interactions with the feline intestinal mucosa and the local immune response. They also highlight the need to further standardize the model to allow clear comparisons. Together with other feline cellular models under development, deciphering these specific interactions will help to improve vaccine strategies and protect animal and public health.
ano.nymous@ccsd.cnrs.fr.invalid (Julie Rouzet) 06 May 2025
https://hal.science/hal-05057357v1
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[hal-05040946] A global review of Cryptosporidium spp. in pigeons in the context of the One-Health concept
<div>Background:<p>The pigeon (Columba livia) is a domesticated bird species that frequently comes into contact with humans. Pigeons harbour and disseminate numerous zoonotic pathogens, including apicomplexan parasites from the genus Cryptosporidium, a common protist parasite of vertebrates. Pigeon populations have increased in urban and peri-urban areas in recent years, which may pose a public health risk. Aim: A systematic review was conducted to examine the presence and prevalence of Cryptosporidium in pigeons worldwide. Methods: The PubMed database was screened for relevant articles between the 1 st January and the 1 st August 2024. A total of 38 publications were included in this review. Results: Cryptosporidium infection in pigeons was first reported in Turkey in 1994, with clinical symptoms including depression, emaciation, inactivity, diarrhoea and feather ruffling. Histological examination revealed the presence of Cryptosporidium in the intestinal epithelium. Subsequent studies have confirmed the prevalence of Cryptosporidium worldwide. Traditional diagnostic methods revealed an average prevalence of 14.8%, while molecular tools indicated a higher prevalence (28.4%). The highest rates were observed in Iraq, where captive pigeons were found to be more commonly infected than wild birds. Molecular data, though limited, suggest that domestic pigeons also harbour more diverse Cryptosporidium spp. than wild pigeons. C. meleagridis, C. parvum and C. hominis were the main zoonotic species identified in pigeons globally. Microscopic analysis showed variation in infection intensity, with oocyst counts ranging from 3,000 to 36,000 per gram of faeces. Many genotypes of Cryptosporidium spp. are considered zoonotic, with known cases of human infection in pigeon handlers. Therefore, it has public health implications. Conclusions: Further studies are needed to clarify the pathogenicity and transmission routes of Cryptosporidium spp. in pigeons. Prevention and control of this zoonosis in pigeons should be a public health priority, particularly in regions with large pigeon populations, such as urban areas where they live in close contact with humans and other animals.</p></div>
ano.nymous@ccsd.cnrs.fr.invalid (Anais Devulder) 20 Apr 2025
https://hal.science/hal-05040946v1
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[hal-05124696] Impacts sur la santé publique de la dynamique des populations de renards
Le Renard roux (Vulpes vulpes) est une espèce de la faune sauvage. En tant que gibier, il peut être chassé par différents moyens. Il est de plus susceptible d’être inscrit, dans certains territoires, comme espèce susceptible d’occasionner des dégâts (ESOD) par arrêté ministériel triennal pris en application de l’article R.427-6 du Code de l’environnement. Nonobstant les restrictions sur les périodes de chasse, les animaux classés ESOD peuvent être éliminés toute l’année. En 2019 et pour trois ans, suite à des consultations départementales et un arbitrage ministériel, le renard a été classé ESOD dans 90 départements français. La décision de classement doit être motivée. Plusieurs arguments sont avancés pour ce classement : pertes dans les élevages avicoles ou de gibier, raisons sanitaires (par ex. : échinococcose alvéolaire, gale sarcoptique). Inversement, des bénéfices liés à la présence des renards sont également avancés, tels que la prédation de rongeurs (campagnols notamment), porteurs d’agents zoonotiques, la réduction d’utilisation de raticides, etc. ... Dans un rapport et avis sur le rôle épidémiologique du renard dans le système multihôtes de la tuberculose bovine (Anses 2021)1, l’Anses notait que l’importance des nuisances attribuées aux renards faisait l’objet de controverses et de polémiques en France. La présente saisine s’inscrit ainsi dans un contexte sociétal sensible impliquant notamment les associations de protection de la nature et les chasseurs ou les éleveurs. Les réponses à cette saisine visent à clarifier le rôle du renard dans l’épidémiologie de certaines zoonoses pour lesquelles il est présenté comme premier responsable de la transmission à l’humain, ce qui motive certains acteurs à proposer son classement en tant qu’ESOD. Dans une approche « une seule santé » (One Health), il est demandé d’identifier les risques pour la santé publique associés à des évolutions significatives, à la hausse et à la baisse, de populations de renards, i.e. : 1) « lister des zoonoses présentes en France pour lesquelles les renards ont un rôle épidémiologique, direct ou indirect (par les populations de proies qu’il élimine) et décrire ce rôle épidémiologique ; 2) identifier, le cas échéant, d’autres familles d’impacts en santé publique (par exemple l’effet indirect sur l’emploi des pesticides tels que les raticides) associés à l’évolution des populations de renards ; 3) expliciter, en fonction des connaissances disponibles (publications, données disponibles ou mécanismes de collecte mobilisables), l’importance relative des effets identifiés aux points 1 et 2, pour l’humain et/ou l’environnement, de l’évolution des populations de renards ; 4) analyser la faisabilité d’une évaluation socio-économique de type coût/bénéfice de la prévention et des impacts associés à ces zoonoses dans lesquels les renards ont des rôles différents, pour l’être humain et/ou l’environnement ». La saisine concerne exclusivement la France métropolitaine. En outre, n’entrent pas dans le champ de la saisine (i) les renards en tant que proies des loups, lynx et grands ducs principalement, ce qui ne constitue pas un enjeu de santé publique, (ii) l’impact des renards prédateurs sur les populations de volailles (basse-cours, élevages aviaires), d’oiseaux sauvages (notamment le gibier), sujet très large qui rejoint un critère de classement ESOD, et (iii) l’impact des renards prédateurs de micromammifères (souris, campagnols, mulots, etc.) à l’origine de dégâts aux cultures, l’expertise se limitant aux populations de proies susceptibles de transmettre des agents de zoonoses.
ano.nymous@ccsd.cnrs.fr.invalid (Emmanuelle Gilot-Fromont) 18 Jul 2025
https://hal.science/hal-05124696v1
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[hal-05180578] Cross-species immune activation and immunobiotics: a new frontier in vector-borne pathogen control
The persistent global burden of vector-borne diseases (VBDs) needs innovative control strategies, as traditional methods are compromised by acaricides and drug resistance and variable vaccine efficacy. We propose a dual-action strategy using cross-species immune activation: human microbiota triggers the production of natural antibodies that directly target pathogens in the host and modulate vector immunity by interacting with vector microbiota. The human microbiota also modulates cytokine responses, enhancing immune defenses in both host and vector. These mechanisms can be further optimized by identifying immunobiotics – specific gut microbes that stimulate protective immune responses against VBDs. This approach offers a sustainable framework to bridge the gap between host and vector immunity, introducing a novel method to combat VBDs.
ano.nymous@ccsd.cnrs.fr.invalid (Alejandro Cabezas-Cruz) 23 Jul 2025
https://hal.inrae.fr/hal-05180578v1
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[hal-05019826] Effets indésirables des soins topiques
Les soins topiques peuvent être responsables d’effets indésirables locaux ou systémiques. Les signes cliniques sont variés et les dermatoses associées également.
ano.nymous@ccsd.cnrs.fr.invalid (Noëlle Cochet Faivre) 03 Apr 2025
https://hal.science/hal-05019826v1
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[tel-05109322] Toxoplasma gondii, Cryptosporidium et Giardia duodenalis : détection, identification et stratégies de lutte
La toxoplasmose, la cryptosporidiose et la giardiose sont des zoonoses cosmopolites d’importance majeure, de par leur impact en santé publique et en santé animale, et, leur impact économique et sociétal. Les protozoaires Toxoplasma gondii, Cryptosporidium et Giardia duodenalis responsables de ces maladies infectieuses sont présents dans les denrées alimentaires et l’environnement. Ils ont été classés en 2012 par les experts de l'Organisation des Nations Unies pour l'alimentation et l'agriculture (FAO) et de l'Organisation mondiale de la Santé (OMS) parmi les 24 parasites à transmission alimentaire d’importance à surveiller. Développer des outils performants de dépistage, de diagnostic, de surveillance et de lutte intégrée vis-à-vis de ces agents de zoonoses est donc essentiel pour mieux comprendre les interactions « hôte-parasite » / « hôte-microbiote-parasite » et les mécanismes de la transmission de ces agents.Les travaux de recherche présentés dans cette thèse ont contribué à la surveillance de la toxoplasmose chez les ovins en évaluant la distribution de l’ADN de T. gondii dans différents organes d’agneaux. Ils ont permis, pour les protozoaires Cryptosporidium et Giardia duodenalis, de développer un modèle expérimental in vivo souriceau nouveau-né utilisé pour le criblage thérapeutique, de caractériser des isolats de Cryptosporidium et de Giardia duodenalis circulant dans les élevages ovins en Algérie et des isolats de Cryptosporidium circulant chez les hérissons d’Europe (Erinaceus europaeus) en région parisienne et, enfin, de mettre en place des outils thérapeutiques et/ou prophylactiques ciblés innovants (utilisation de probiotiques pour lutter contre la giardiose) et d’une méthode de détection (mise au point d’aptamères ADN) de ces agents entéropathogènes.Ces travaux de recherche, combinant à la fois, la protection de la santé animale et la protection de la santé publique, en lien avec leur environnement, s’inscrivent dans une approche « One Health, une seule santé ».
ano.nymous@ccsd.cnrs.fr.invalid (Myriam Thomas) 12 Jun 2025
https://theses.hal.science/tel-05109322v1
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[hal-05038698] Isolation of derivatives from the food-grade probiotic <i>Lactobacillus johnsonii</i> CNCM I-4884 with enhanced anti-Giardia activity
Giardiasis, a widespread intestinal parasitosis affecting humans and animals, is a growing concern due to the emergence of drug-resistant strains of G. intestinalis. Probiotics offer a promising alternative for preventing and treating giardiasis. Recent studies have shown that the probiotic Lactobacillus johnsonii CNCM I-4884 inhibits G. intestinalis growth both in vitro and in vivo. This protective effect is largely mediated by bile salt hydrolase (BSH) enzymes, which convert conjugated bile acids (BAs) into free forms that are toxic to the parasite. The objective of this study was to use adaptive evolution to develop stress-resistant derivatives of L. johnsonii CNCM I-4884, with the aim of improving its anti-Giardia activity. Twelve derivatives with enhanced resistance to BAs and reduced autolysis were generated. Among them, derivative M11 exhibited the highest in vitro anti-Giardia effect with enhanced BSH activity. Genomic and proteomic analyses of M11 revealed two SNPs and the upregulation of the global stress response by SigB, which likely contributed to its increased BAs resistance and BSH overproduction. Finally, the anti-Giardia efficacy of M11 was validated in a murine model of giardiasis. In conclusion, our results demonstrate that adaptive evolution is an effective strategy to generate robust food-grade bacteria with improved health benefits.
ano.nymous@ccsd.cnrs.fr.invalid (Anne-Sophie Boucard) 17 Apr 2025
https://hal.science/hal-05038698v1
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[hal-05027514] Octopamine and adrenergic-like octopamine receptors in Ixodes ricinus salivary glands
The neurotransmitter octopamine, a structural and functional analogue of the vertebrate adrenaline, plays essential roles in various aspects of invertebrate physiology. Here, using in silico approaches we identified that in tick genomes two types of adrenergic-like octopamine and two types of tyramine receptors are present. Among those, transcripts of Ixodes ricinus α-2 adrenergic-like octopamine receptor (Octα2R) and its β counterpart (OctβR) have been chemically synthetized and functionally tested in the heterologous expression system. For both receptors, octopamine was the most potent activator followed by adrenaline and noradrenaline, while dopamine did not show any effect. Furthermore, an antibody against octopamine revealed six pairs of neurons in the protocerebral neuronal cells in the Ixodes synganglion. Subsequent immunostaining with an antibody against the tyramine β-hydroxylase (TBH), an enzyme synthetizing octopamine, confirmed the reaction in three pairs of those neurons. In salivary glands octopamine-like immunoreaction has been detected on luminal site of type II and III acini as scattered patches in close association with a single myoepithelial cell. In addition, double staining of octopamine with known markers for Ixodes salivary gland axons, the neuropeptides and invertebrate-like dopamine receptor, showed distinct staining patterns. Interestingly the anti-TBH antibody recognized robust basal axons reaching both type II and III acini as well as fine scattered patches in close association with octopamine-like immunosignal in the same structures. Thus our results indicate axonal delivery of octopamine to Ixodes salivary gland. Finally, injection of octopamine to partially fed Ixodes females triggered saliva secretion, however with about 10 minutes delay after the injection. Our pioneer study represents a steppingstone for a deeper molecular and biochemical exploration of the octopamine physiology in tick salivary glands.
ano.nymous@ccsd.cnrs.fr.invalid (Sabine Rakotobe) 09 Apr 2025
https://hal.inrae.fr/hal-05027514v1
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[hal-05027541] Insight into the tick neurosecretory system
Neurosecretory cells (NSC) are defined as specialized neurons that produce and release chemical messengers into the bloodstream to target distant tissues. Although, it seems that tick and insect nervous systems have developed convergently, as of today the information about tick neurosecretory system along its releasing sites remains literally a “black box”. In presented work we used specific antibodies against different classes of neuropeptides to reveal completely novel lateral and medial clusters of peptidergic NSC in the anterior protocerebrum of Ixodes ricinus synganglion. On one hand, each of these NSC, form a rich axonal network on the dorso-lateral surface of the synganglion, while on the other hand also send their axons into nearly all internal lobes of this organ. Immunogold transmission electron microscopy confirmed that surface axons of these cells terminate within the dorsal perineurium and release the neuropeptides towards an acellular neurilemma layer, that faces the circularly fluid, the haemolymph. We also found that axon terminals of both lateral and medial NSC are sensitive to acetylcholine (ACh) neurotransmitter as they express type A and B muscarinic acetylcholine receptors, respectively. Injection of 100 nL water into unfed I. ricinus female haemocoel intensified the fluorescent neuropeptide signal in these axon terminals, while the same volume containing 10 μM ACh had a significantly reduced effect. Here, we hypothesize that increased fluorescence is associated with accelerated neuropeptide synthesis and subsequent transport to axon terminals as a consequence of sensing the changes in the haemolymph volume. On the other hand, a decreased fluorescent signal indicates that ACh mediates release of these neuropeptides that act as hormones for the regulation of osmoregulatory or other physiological processes. Based on these results we propose a unique model of hormonal acetylcholine-triggered released of peptide hormones in ticks.
ano.nymous@ccsd.cnrs.fr.invalid (Ladislav Šimo) 09 Apr 2025
https://hal.inrae.fr/hal-05027541v1
