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BIPAR JRU

Molecular Biology and Parasitic Immunology

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JRU "Molecular Biology and Parasite Immunology"

JRU BIPAR's activities are focused on the study of Host-Pathogen Interactions, as well as on the detection, characterisation and circulation of pathogens:
- food-borne zoonotic parasites.
- vectors (ticks, mosquitoes) and the pathogens vectored by them (bacteria, parasites and viruses).
The JRU also hosts :
- a National Reference Laboratory for food-borne parasites, excluding Echinococcus
- an WOAH collaborating centre on food-borne zoonotic parasites, which shares reference research projects with the Paralim team and carries out national and international reference activities.

 

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article

07 August 2025

By: S. BERTRAND/C. ROUXEL

Thesis defence Caina NING

Subject of thesis: Cholinomimetics-Mediated Activities of Peptidergic Neurons Innervating the Salivary Glands of the Tick Ixodes ricinus
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Lisa Le Dortz thesis defence

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PhD topic: Aptamers, new tools for studying and detecting Anaplasma phagocytophilum, a strict intracellular zoonotic bacterium.

Publication of the book "Tiques, Lyme & Cie" (Editions SCITEP, March 2019)

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The recent interest in ticks and tick-associated diseases is justified by the seriousness of some of these diseases, and by proven changes in the distribution of tick populations due to socio-economic and environmental changes. In Europe, ticks are the main vectors of importance for human and animal health, and are responsible for transmitting viruses, bacteria and parasites. Lyme disease alone crystallises the majority of tick-related concerns, and is the subject of both societal and scientific debate. Faced with a multitude of sometimes alarmist information about the risk of contracting this disease, it is essential to think rationally and scientifically. Knowing the biology of ticks and the ways in which they may or may not transmit infectious agents is an essential asset in protecting against them.

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HAL : Dernières publications

  • [hal-05298829] Effects of host sex, age and behaviour on co-infection patterns in a wild ungulate.

    Recent zoonotic disease emergences emphasize the importance of studying wildlife parasite communities. As wild hosts frequently harbour diverse parasite species, understanding the drivers of multiple infection patterns in free-ranging hosts is critical for elucidating the ecological and epidemiological dynamics of parasite communities. In this study, we analysed co-infection patterns in European roe deer (Capreolus capreolus) inhabiting a fragmented rural landscape in southwestern France. Using data from 130 samples of GPS-tracked deer, we examined the influence of proximity to livestock, host activity levels, age, sex, and between-parasite interactions on the presence of 11 parasitic taxa. Hierarchical modelling of species communities (HMSC) revealed that proximity to livestock significantly increased the likelihood of infection with orofecally transmitted parasites (Toxoplasma gondii, gastrointestinal parasites). Sex and age were other key predictors, with males and juveniles exhibiting a higher frequency of parasite presence, likely influenced by hormonal and immune system differences. Activity levels showed distinct age-related effects, with higher activity levels being positively associated with increased parasite prevalence in yearlings, but not in adults. In contrast, parasite association patterns within individual hosts were weak, suggesting minimal interactions between parasite species. Our findings highlight the interplay between exposure and susceptibility in shaping co-infection patterns and underscore the value of hierarchical modelling approaches in multi-parasite systems.

    ano.nymous@ccsd.cnrs.fr.invalid (Florian Berland) 06 Oct 2025

    https://hal.inrae.fr/hal-05298829v1
  • [hal-05264821] A clinical case of ophidiomycosis in Esculapian snake (Zamenis longissimus) in France

    Ophidiomyces ophidiicola, agent mycosique responsable d' ophidiomycose chez les reptiles, est une menace croissante pour les populations de serpents en Europe, en particulier les colubridés. Décrit en Europe pour la première fois en 2017, l'agent pathogène est détecté annuellement en France, dans le Doubs, depuis 2021. Nous décrivons ici le premier cas clinique avec évidence de l'implication du pathogène dans la mort d'un juvénile non captif de Couleuvre d'Esculape (Zamenis longissimus), investigué dans le cadre de la surveillance sanitaire événementielle du réseau SAGIR. Bien que la couleuvre d'Esculape ne soit pas, en France, une espèce fortement menacée, la circulation active d'O. ophidiicola associée à de la mortalité dans les populations non-captives est une menace pour l' ensemble des espèces de serpents en France, qui doit être prise en compte dans les actions de conservation des espèces.

    ano.nymous@ccsd.cnrs.fr.invalid (Loïc Palumbo) 17 Sep 2025

    https://hal.science/hal-05264821v1
  • [hal-05267747] 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) 18 Sep 2025

    https://hal.science/hal-05267747v1
  • [hal-05241503] Distribution of Clinostomum complanatum in two commercially important freshwater fish, perch and rudd, in France

    Over the last two decades, the popularization of new eating habits and the increase in fish products demand led to a raising risk for consumers due to food-borne parasitic zoonoses. Species of Clinostomum Leidy, 1856 are cosmopolitan zoonotic digenetic trematodes. They are present, at the juvenile stage, in numerous freshwater fish. Among them, Clinostomum complanatum may induce pharyngitis or laryngitis in humans following consumption of raw fish infected by the metacercariae. In France, the first mention of Clinostomum spp. metacercariae on freshwater fish was made in the Durance River in 2008, with almost no data and very obscure conclusions. However, recently, the infection of a batch of wild perch in the Jura in December 2019 was described. The present study provides the first evidence of the extent of the distribution of C. complanatum across continental France based on sampling of freshwater fish (European perch and rudd) from different departments. A survey of infection levels was realized on 14 batches of fish collected in eight departments. Fish were sampled by recreational anglers or pond fish farmers. They were dissected for the presence of C. complanatum metacercariae. All metacercariae were identified based on molecular analyses on mtDNA cox1 gene fragment and rDNA 28S gene fragment. Encysted metacercariae were found in five departments and in 113 out of 526 sampled fish. Intensity of infection ranged from 4 to 25 parasites per fish. All metacercariae were identified as C. complanatum. Phylogenetic and haplotype network analyses reported low genetic diversity in French C. complanatum individuals on mtDNA cox1 marker indicating the absence of distinct populations in the French territory. French specimens shared common mtDNA haplotypes with C. complanatum specimens from Italy. This study confirmed the presence of this zoonotic trematode species in freshwater consumed fish, and expanded the known geographical distribution area in France. Moreover, the high intensity and prevalence recorded suggested it could represent a hazard both to human and animal health. We discuss how future research should address the zoonotic risk of this parasite and ensure the health safety of fish-based products and new consumer habits.

    ano.nymous@ccsd.cnrs.fr.invalid (Maureen Duflot) 05 Sep 2025

    https://hal.science/hal-05241503v1
  • [hal-05214519] Anaplasma marginale modulates the microbiota of Rhipicephalus microplus organs involved in pathogen transmission

    The cattle tick Rhipicephalus microplus is a vector for Anaplasma marginale in tropical and subtropical regions worldwide. The study of pathogen-microbiome-vector interactions at the tick organ scale is a promising area of development, unraveling control strategies for tick-borne diseases. Our study focused on how A. marginale infection affects the bacterial community within the salivary glands and ovaries of R. microplus. Engorged female ticks collected from cattle in a disease-endemic area of Argentina were further classified based on whether they were infected with A. marginale by targeting the msp1β gene through PCR diagnosis in tissue samples. We included negative control samples throughout the study. We analyzed the bacterial communities in tick tissues by sequencing the 16S rRNA V3-V4 region. Our results revealed significant differences in community composition between infected and uninfected samples. Sphingomonadaceae was identified as a predominant taxon in uninfected salivary glands and ovaries. Additionally, we constructed co-occurrence networks to study interactions within the microbial communities. It is noteworthy that A. marginale infection led to an increase in network complexity in the salivary glands, exerting the opposite effect on the ovaries. These findings reinforced the hypothesis that A. marginale impacts the microbiota of R. microplus at an organ-specific level.

    ano.nymous@ccsd.cnrs.fr.invalid (Agustina E Pérez) 19 Aug 2025

    https://hal.inrae.fr/hal-05214519v1
  • [hal-05299142] Prevalence and risk factors of Parascaris spp. infection in equids under two years old in france

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    ano.nymous@ccsd.cnrs.fr.invalid (Kenza Bourrier) 06 Oct 2025

    https://hal.science/hal-05299142v1
  • [hal-05214923] Anti-microbiota vaccine induces lysine-mediated modulation of tick immunity affecting Borrelia colonization

    Tick microbiota influences Borrelia colonization, but changes in the microbiota-derived metabolite and how this affects tick physiology and vector competence is unclear. We investigated whether microbiota-induced metabolite modifications influence tick physiology and pathogen transmission. Using an anti-microbiota vaccine (live Escherichia coli) to immunize mice, we generated host antibodies that modulated the tick microbiome, decreasing bacterial abundance and increasing lysine levels in ticks. Elevated lysine correlated with increased tick weight. Lysine supplementation experiments enhanced defensin expression with DefMT6 exhibiting anti-Borrelia activity, reducing pathogen load in ticks. Our findings demonstrate that anti-microbiota vaccines induce metabolite changes, affecting tick physiology, immunity, and vector competence. These insights open new avenues for developing microbiota-targeted strategies to control tick-borne diseases

    ano.nymous@ccsd.cnrs.fr.invalid (Lourdes Mateos-Hernandez) 19 Aug 2025

    https://hal.science/hal-05214923v1
  • [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) 13 Aug 2025

    https://hal.science/hal-05154805v3
  • [hal-05235475] Resistance to Antileishmanial Drug Candidates: A Flowchart for an Early Phenotypic Evaluation of Risk

    Background: Drug development for leishmaniases treatment follows a very selective process in order to propose drug candidates that possess all the qualities that meet the strict specifications of the pharmaceutical industry. Drug resistance is a limiting factor that can impact the lifespan of a marketed drug. It is now essential that the risk of drug resistance be evaluated at the early stage of in vitro studies to discard a lead compound that could quickly generate drug resistance once available on the market. Objectives: This article aims to estimate the risk of drug resistance emergence for a promising drug candidate at the in vitro early stage of drug development. Methods: A sequential method is proposed to study some of the phenotypic characteristics and parameters of resistant parasites such as time to achieve maximal resistance during stepwise drug pressure, resistance amplitude, stability, fitness, and infectivity both in vitro and in vivo. Results: Some examples with drugs in clinical use and former drug candidates are given. Conclusions: This method providing an evaluation of the risk of drug resistance from an in vitro model of Leishmania donovani be extrapolated to other Leishmania species.

    ano.nymous@ccsd.cnrs.fr.invalid (Nalia Mekarnia) 02 Sep 2025

    https://hal.science/hal-05235475v1
  • [hal-05169453] Assessment of ex vivo antimalarial drug efficacy in African Plasmodium falciparum parasite isolates, 2016–2023: a genotype–phenotype association study

    Background: Given the altered responses to both artemisinins and lumefantrine in Eastern Africa, monitoring antimalarial drug resistance in all African countries is paramount. Methods: We measured the susceptibility to six antimalarials using ex vivo growth inhibition assays (IC50) for a total of 805 Plasmodium falciparum isolates obtained from travellers returning to France (2016-2023), mainly from West and Central Africa. Isolates were sequenced using molecular inversion probes (MIPs) targeting forty-three genes across the parasite genome, of which nineteen are drug resistance genes. Findings: Ex vivo susceptibility of all assessed antimalarial compounds was consistent with their potent activity. The median IC50 values for the six drugs were 1.1 nM [IQR: 0.8-1.7] for DHA, 16.7 nM [9.9-27.4] for LMF, 29.5 nM [19.1-45.5] for MFQ, 23.4 nM [17.1-39.0] for MDAQ, 26.7 nM [18.0-41.2] for CQ, and 18.5 nM [15.1-24.3] for PPQ. Only four isolates carried a validated pfkelch13 mutation. Multiple mutations in pfcrt and one in pfmdr1 (Asn86Tyr) were significantly associated with altered susceptibility to multiple drugs, and their frequencies decreased over time. Pfcrt and pfmdr1 mutations altered susceptibility to lumefantrine and mefloquine in an additive manner, with the wild-type haplotype (pfcrt K76-pfmdr1 N86) exhibiting the lowest susceptibility. Interpretation: Our study on P. falciparum isolates from West and Central Africa indicates a low frequency of molecular markers associated with artemisinin resistance and a modest but significant decrease (1.6-2.3X) in the frequency of multidrug resistance markers. These genotypic changes likely mark parasite adaptation to sustained drug pressure and call for intensifying the monitoring of antimalarial drug resistance in Africa.

    ano.nymous@ccsd.cnrs.fr.invalid (Jason Rosado) 21 Jul 2025

    https://univ-angers.hal.science/hal-05169453v1
  • [hal-05214091] Design, development, and testing of a new multi-locus sequence typing scheme for the zoonotic pathogen Cryptosporidium parvum

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    ano.nymous@ccsd.cnrs.fr.invalid (Karin Troell) 19 Aug 2025

    https://hal.science/hal-05214091v1
  • [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
  • [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
  • [hal-05214455] Geographic variation in the microbiome of Varroa destructor in the neighbouring countries Slovakia and Czechia

    Varroa destructor mite is a major threat to honeybee (Apis mellifera) populations, contributing to colony losses through parasitism and pathogen transmission. While extensive research has focused on Varroa biology and its role as a virus vector, its microbiome remains poorly understood, particularly regarding geographic variation. Here, we investigated the micro- bial diversity, composition, and functional potential of Varroa mite microbiota collected from two neighboring countries, Czechia and Slovakia. Using high-throughput sequencing and network analysis, we assessed alpha and beta diversity metrics, microbial co-occurrence patterns, and predicted metabolic functions. Our results revealed significant differences in microbial diversity between the two regions, with some bacterial taxa appearing more prevalent in specific populations. Network analysis suggested potential variation in the structural stability of microbial communities in Varroa mites, raising the possibility that geographic factors may influence microbial interactions. Functional profiling indicated region-associated differences in predicted metabolic pathways, possibly linked to certain bacterial taxa. While these findings provide new insights into the Varroa microbiome and its potential ecological role, the interpretation of geographic influence remains a subject of ongoing investigation to better understand its scope and underlying mechanisms. A deeper understanding of these microbial dynamics may contribute to the development of novel strategies for Varroa mite management and the conservation of honeybee health

    ano.nymous@ccsd.cnrs.fr.invalid (Štefánia Skičková) 01 Sep 2025

    https://hal.inrae.fr/hal-05214455v1
  • [hal-05214436] Diversity of the Ixodes ricinus Microbiome Across Belgian Ecoregions and Its Association with Pathogen and Symbiont Presence

    [...]

    ano.nymous@ccsd.cnrs.fr.invalid (Camille Philippe) 19 Aug 2025

    https://hal.inrae.fr/hal-05214436v1
  • [hal-05214154] Detection of the zoonotic nematode Angiostrongylus cantonensis in Pacific crustaceans by real-time PCR

    [...]

    ano.nymous@ccsd.cnrs.fr.invalid (Thomas Guilmin) 19 Aug 2025

    https://hal.science/hal-05214154v1
  • [hal-05214960] Pathogen surveillance in vectors using high throughput real time microfluidic PCRs

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    ano.nymous@ccsd.cnrs.fr.invalid (Sara Moutailler) 19 Aug 2025

    https://hal.science/hal-05214960v1
  • [hal-05214052] Exploring virus-host interactions through combined proteomic approaches identifies BANF1 as a new essential factor for African Swine Fever Virus

    [...]

    ano.nymous@ccsd.cnrs.fr.invalid (Juliette Dupré) 19 Aug 2025

    https://hal.science/hal-05214052v1
  • [hal-05214935] Living with ticks: Results of an online survey of the knowledge, attitudes and practices (KAP) regarding ticks and tick-borne pathogens in academic environments across Europe

    We prepared a digital questionnaire to capture knowledge, attitudes and practices (KAP) regarding ticks and tick-borne pathogens (TBPs) in 20 languages. The questionnaire was distributed to 21 universities and research institutions in 22 European countries and 9401 valid responses were collected. Most survey participants identified ticks correctly and regarded ticks as a serious health risk. There was also a good level of knowledge regarding tick activity, habitats and the predominant TBPs in the country or region. Moreover, most respondents were familiar with effective tick protection and removal measures. Over 75 % of respondents had been bitten by ticks and up to 12 % of participants had been diagnosed with a tick-borne infection in the past. Respondents from northern and central European countries who reported engaging in outdoor activities more frequently, reported increased frequencies of tick bites and infection with TBPs compared to respondents from southern Europe. Awareness of national information campaigns on ticks and TBPs was also greater among respondents from northern and central European countries than among Mediterranean countries. This study identified knowledge gaps among respondents from some European countries where TBPs have not been prioritised historically. These knowledge gaps should be addressed by reputable bodies to encourage personal protective behaviours without causing alarm and to forestall the spreading of incorrect and unreliable information propagated by some social media sources.

    ano.nymous@ccsd.cnrs.fr.invalid (Agustín Estrada-Peña) 21 Aug 2025

    https://hal.science/hal-05214935v1
  • [hal-05144005] High‐throughput microfluidic real‐time PCR as a promising tool in disease ecology

    Among recent advances in molecular biology for studying infectious diseases, the microfluidic high‐throughput real‐time polymerase chain reaction (Htrt PCR) has emerged as an efficient first‐line tool for the detection of a wide range of infectious agents (IA) in a host system. This technology allows large batches of samples to be screened simultaneously for tens of targeted IA by real‐time PCR. It represents a promising tool in disease ecology. As a proof of concept, we present here the development steps and initial application of a microfluidic Htrt PCR system for the detection of DNA from 28 selected IA in a set of wild vertebrates. We applied this approach to 497 samples (mainly mucosal swabs and necropsy tissues) from 274 seabirds and 80 mammals from Southern Ocean islands. This ecosystem is of particular interest for disease ecology and biodiversity conservation due to the high host densities of breeding colonies, within and among which pathogens may spread rapidly. Positive samples were subsequently confirmed for each PCR system using a secondary real‐time or conventional PCR system and/or sequencing. Fourteen targeted IA were detected. The approach allowed an efficient screening of host species for known seabird pathogens, including Pasteurella multocida (avian cholera) (9.9% [6.6–14.0] in seabirds, 18.3% [9.5–30.4] in mammals) and Erysipelothrix amsterdamensis (15% [11–19.8] in seabirds, 2.1% [0.4–6.1] in mammals) in cloacal and rectal swabs. Their detection on islands where they were not known previously raised conservation concerns. IA not previously known to be circulating in the system were detected at high prevalence, notably Chlamydiaceae on all colonies (32.1% [26.6–38] in seabirds and 21.3% [12.9–31.8] in mammals, in cloacal and rectal swabs). Prevalence and diversity of targeted IA could be compared among sites and host species, highlighting the usefulness of the approach to explore drivers of IA community dynamics, but also to identify specific hosts as potential epidemiological sentinels or reservoirs. Htrt PCR is a powerful and versatile tool that can be used in disease ecology for exploring the composition of IA communities within host communities, but also for addressing other important basic and applied questions in multi‐host, multi‐pathogen systems.

    ano.nymous@ccsd.cnrs.fr.invalid (Tristan Bralet) 30 Jul 2025

    https://hal.science/hal-05144005v1
  • [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
  • [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
  • [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
  • [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
  • [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
  • [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
  • [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
  • [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
  • [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
  • [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
  • [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
  • [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 (Ines Carreira Costa) 21 Jul 2025

    https://hal.science/hal-05173348v1
  • [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
  • [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
  • [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
  • [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
  • [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
  • [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
  • [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
  • [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
  • [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
  • [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
  • [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
  • [hal-05172503] Prévalence et facteurs de risques d’infestation des jeunes équidés normands par le nématode Parascaris spp

    [...]

    ano.nymous@ccsd.cnrs.fr.invalid (Kenza Bourrier) 21 Jul 2025

    https://hal.science/hal-05172503v1
  • [hal-05149237] Re-sensitization of antimony-resistant Leishmania by highly potent SbV-porphyrin through the involvement of ERG6-coding gene

    [...]

    ano.nymous@ccsd.cnrs.fr.invalid (Ellen Gonçalves De Oliveira) 07 Jul 2025

    https://hal.science/hal-05149237v1
  • [hal-05131886] Culicoides insignis in Ecuador: Molecular identification of blood meals and detection of bluetongue virus

    [...]

    ano.nymous@ccsd.cnrs.fr.invalid (Juan Mosquera) 25 Jul 2025

    https://hal.science/hal-05131886v1
  • [hal-05130134] Systematic review of zoonotic parasites in game in Europe

    [...]

    ano.nymous@ccsd.cnrs.fr.invalid (Helga Waap) 25 Jun 2025

    https://hal.science/hal-05130134v1
  • [hal-05168360] Quels parasites digestifs infestent les jeunes équidés normands ?

    [...]

    ano.nymous@ccsd.cnrs.fr.invalid (Kenza Bourier) 17 Jul 2025

    https://hal.science/hal-05168360v1
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