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[hal-05707232] Expanding the role of thiophilic metallodrugs in antiparasitic chemotherapy: multi-target approaches against protozoan parasites
Parasitic diseases' chemotherapy faces several challenges, mainly through harbouring options that lack safety profiles, combined with the emergence of drug resistance that reduces their effectiveness. To circumvent such limitations, new therapeutic approaches are urgently needed. Among several tools, a practical and less time-and money-consuming approach is to repurpose existing drugs to tackle different diseases. Pentavalent antimonials, used for treating leishmaniases, stand out by offering a multi-target mode of action, mainly against cysteinebased proteins (e.g., trypanothione reductase, and zinc-finger motifs). Over the last few years, efforts from the scientific community have been gathered to identify and characterise proteins containing zinc-finger motifs, across several parasites that could constitute alternative targets based on their functionality, non-existence in the host, and eventual homology between parasites. Aiming to repurpose and amplify the range of metallodrugs by combining other metals, this review focuses on two points. Primarily, the exploration of the latest advancements in identifying crucial parasitic proteins that contain zinc-finger motifs, which could be exploited in the future as novel metallodrug targets. Finally, this review also highlighted novel metallodrugs featuring thiophilic metals, such as gold, silver, copper, palladium, platinum, and ruthenium, which have been disclosed, especially over the last five years, in the field of parasitic diseases, as well as their mode of action.
ano.nymous@ccsd.cnrs.fr.invalid (Inês C C Costa) 30 Jul 2026
https://hal.inrae.fr/hal-05707232v1
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[pasteur-05709898] Ancient and current association of the Trichinella complex with negative-sense and double-stranded RNA viruses
The earliest records of Trichinellosis might be found in bibles that recommend against pork consumption due to the spread of a disease that resembles what is now identified as Trichinellosis. Parasitic nematodes (round worms) of the genus Trichinella form a complex of at least 13 species with a broad geographic range. Herein, through data mining of transcriptomic data, and re-sequencing of the transcriptome of representative isolates, we demonstrate the presence of viruses within 10 recognized Trichinella species. We provide genome sequences of four viral species of negative sense RNA viruses that belong to the Family Lispiviridae , Order Mononegavirales, and of eight novel viruses of double-stranded RNA viruses that belong to a novel sub-order within the order Ghabrivirales . The integration of viral genome fragments within encapsulated Trichinella genomes demonstrates that these parasite-virus associations are ancient. Overall, viruses show co-diversification with their parasitic hosts. Yet the phylogenetic position of viruses revealed past host jump from an ancestral encapsulated Trichinella species to the ancestral T. pseudospiralis and challenges previous dogma on the phylogeny and biogeography of Trichinella species in North America. IMPORTANCE We are witnessing the emergence of a novel field of research focusing on viruses of parasites and their role in parasite pathogenicity. Herein, we describe the characterization of viruses within 10 recognized species of Trichinella . The viruses were distantly related to known viruses which led us to propose the creation of a novel genera and a novel sub-order. We demonstrated the integration of viral genome fragments within the genome of Trichinella species and an on-going process of birth and death of viral integration. Finally, we showed that virus phylogenetic analyses can provide fine-tuned information about their parasitic host evolutionary history. This study demonstrates the ancient and close association between Trichinella and viruses and strong species specificity. Further studies are now needed to determine whether the newly discovered viruses could be targeted for the development of novel diagnostic approaches.
ano.nymous@ccsd.cnrs.fr.invalid (Gregory Karadjan) 03 Aug 2026
https://pasteur.hal.science/pasteur-05709898v1
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[hal-05704995] Exploring Normal to Abnormal Variations of Grooming Behaviours in Cats
ABSTRACT Background Grooming is a maintenance behaviour accounting for 4% of a cat's activity budget. It consists of several short bouts, and is modified by pruritus and some psychogenic diseases in cats. Objectives This study aimed to describe cats' grooming behaviour, investigating normal variations in relation to hair length and grooming modifications in cats with psychogenic alopecia (fPA). Materials and Methods We analysed 118 videos of 29 healthy cats and seven fPA shorthair cats. We studied five activities for nine body parts performed by cats during grooming, the duration and number of grooming bouts, according to hair length and health status. Results Major individual variations occurred between cats, with no differences regarding mean grooming bout duration according to hair length or health status. Most (95%) grooming bouts consisted in grooming two to seven body parts. Number of parts groomed by fPA cats was significantly lower than healthy shorthair cats; no differences were noted between healthy cats with different hair length. Hairless cats chewed their skin longer than other cats. fPA cats chewed their skin 10 times longer than healthy shorthair cats ( p < 0.001). Licking and rubbing were shorter bouts ( p = 0.021). Time spent grooming each zone did not differ with hair length. fPA cats groomed their internal hind limbs significantly longer ( p = 0.016) and their neck shorter ( p = 0.003) than healthy shorthair cats. Conclusions and Clinical Relevance This study allows a better understanding of cats' grooming behaviour, helping to identify abnormal grooming behaviours, and supports classification of psychogenic alopecia as an abnormal repetitive behaviour.
ano.nymous@ccsd.cnrs.fr.invalid (Mathilde Guillon) 27 Jul 2026
https://hal.science/hal-05704995v1
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[hal-05710792] Prevalence of Borrelia spp. and Rickettsia spp. in Ixodes ricinus Occurring in Suboptimal Meadow Habitats in Eastern Poland
Ixodes ricinus is the principal vector of numerous tick-borne pathogens (TBPs) in Europe and is typically associated with forest sites that provide favorable microclimatic conditions. However, this species may also occur in meadow ecosystems, which are generally regarded as suboptimal environments and remain insufficiently studied from an epidemiological perspective. The aim of this study was to determine and compare the prevalence of Borrelia spp. and Rickettsia spp. in adult I. ricinus occurring in urban and rural meadow sites in eastern Poland. Ticks collected between June 2023 and May 2024 were screened for Borrelia spp. and Rickettsia spp. using high-throughput microfluidic real-time PCR targeting the 23S rRNA and ITS regions, respectively. The DNA of Borrelia spp. was detected in 14.8% of ticks from the urban site and 10.7% from the rural site, whereas Rickettsia spp. were detected in 5.6% and 8.9% of specimens, respectively. No significant differences in pathogen prevalence were observed between sites. The results confirmed the presence of Borrelia spp. and Rickettsia spp. in adult I. ricinus collected in urban and rural meadow sites.
ano.nymous@ccsd.cnrs.fr.invalid (Joanna Kulisz) 04 Aug 2026
https://hal.science/hal-05710792v1
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[hal-05715147] Natural antibodies induced by host gut microbiota modulate tick microbiota, inhibiting Borrelia colonization
The gut microbiome undergoes natural selection pressure, likely because it can affect infection resistance by stimulating natural antibody (NAb) production, notably against the glycan Galα1–3Galβ1–4GlcNAc-R (α-Gal). In our study, we explored whether particular glycans, such as α-Gal, from specific host microbiota components could trigger NAbs that, once ingested by Ixodes ricinus ticks during the blood meal, are capable of cross-reacting with bacterial strains in the tick microbiota that share these glycans. Such interactions might alter the tick microbiota and reduce Borrelia afzelii colonization in ticks. When mice were orally administered various Escherichia coli strains, it triggered the stimulation of NAbs and resulted in strain-specific alterations in the tick microbiota. These changes effectively decreased Borrelia colonization in the tick vector. Additionally, vaccination with the glycan α-Gal induced notable shifts in the tick microbiota and similarly reduced Borrelia colonization. Reduced Borrelia colonization was associated with shifts in bacterial diversity, abundance, and microbial network properties. The study provides evidence that natural mechanisms, such as the production of NAb in response to the host gut microbiome, can modulate the microbiota of disease vectors and reduce pathogen colonization within the vector. These findings offer new insights into potential strategies for reducing the transmission of vector-borne diseases through modulation of the host gut microbiome.
ano.nymous@ccsd.cnrs.fr.invalid (Lourdes Mateos-Hernandez) 11 Aug 2026
https://hal.science/hal-05715147v1
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[hal-05693623] Morphological abnormalities in Afrixodes ticks
In mythology, teratology refers to fantastic creatures and monsters, but the “science of monsters” in biology refers to congenital abnormalities and abnormal formations. These anomalies are well reported in ticks, but only a few of them deal with Ixodes ticks, ticks collected from wildlife, or ticks from Africa. This study investigated a large collection of Afrotropical ticks, Ixodes (Afrixodes), collected from wildlife, which included two nymphs (Ixodes (A.) spp.) and one adult female (I. rasus) that turned out to be teratological specimens, presenting ectromely (missing leg). The present work represents the first report of morphological abnormalities in Ixodes (A.) rasus and Ixodes (A.) spp. collected on Muridae, Soricidae and Tragulidae in the Central African Republic and Gabon.
ano.nymous@ccsd.cnrs.fr.invalid (Camille Lorang) 15 Jul 2026
https://hal.science/hal-05693623v1
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[hal-05630782] Zoonotic Cryptosporidium and Giardia infections in pigeons (Columba spp.) at a wildlife hospital in France: Occurrence and molecular identification
The feral rock pigeon (Columba livia domestica) and wood pigeon (Columba palumbus) are ubiquitous species found in cities worldwide. Its interaction with humans, domestic animals and wild birds makes them potential carriers of transmissible pathogens, including zoonotic parasites. The aim of this study was to identify protozoan parasites belonging to the genera Cryptosporidium spp. and Giardia spp. in these two pigeon species hosted at the Wildlife Animal Hospital of the Veterinary School of Alfort, in France. Fecal samples from 367 pigeons (Columba livia and Columba palumbus) including a wide majority of juveniles, were collected and analysed using both direct immunofluorescence and molecular identification techniques, including PCR targeting the small subunit ribosomal RNA and the 60 kDa glycoprotein gene of SSU rDNA. Eighty-six and 12 fecal samples tested positive for Cryptosporidium spp. and Giardia spp. by immunofluorescence, respectively. Young pigeons appeared to be infected by Cryptosporidium spp. more frequently than adults. In addition, wood pigeons seemed to be infected by Giardia spp. more often, while rock pigeons had a higher occurrence of Cryptosporidium spp. Phylogenetic analysis revealed the presence of zoonotic species including C. meleagridis, C. parvum, and G. duodenalis assemblage B. As these species are known to infect humans, pigeons could represent a potential source of zoonotic transmission.
ano.nymous@ccsd.cnrs.fr.invalid (Anaïs Devulder) 22 May 2026
https://hal.science/hal-05630782v1
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[hal-05578664] Lower prevalence of Lyme disease pathogens in mixed deciduous – coniferous forests
A growing number of studies demonstrate the consequences of biodiversity loss on the increased prevalence of vector-borne diseases such as Lyme borreliosis. Given that vertebrate host species differ in their competence for pathogen transmission, it has been hypothesized that greater host diversity, which is more likely to occur in mixed forests, would reduce pathogen prevalence in ticks through a dilution effect. However, empirical evidence remains mixed, particularly in Europe, and recent studies suggest that habitat characteristics and vegetation structure may also play a key role in the risk of tick-borne disease. We sampled ticks along gradients of forest compositional diversity in a network of seven sites in Europe to assess the combined effect of tree and understorey plant diversity on ticks and associated pathogens. We found that several forest habitat characteristics were associated with variations in Ixodes ricinus densities and infection rates. The proportion of I. ricinus nymphs infected by Borrelia was lower in mixed than in pure forests. The prevalence of Borrelia and Rickettsia respectively increased and decreased with the richness of understorey plants. Ixodes ricinus larvae density increased with the proportion of plants palatable to roe deer (Capreolus capreolus). Our results suggest that forest diversity, at both tree and understorey levels, influences ticks and associated pathogens through several direct and potential indirect mechanisms such as effects on vertebrate hosts, particularly herbivores. Habitat and resource diversification of vertebrate hosts provides a useful theoretical framework to guide forest management toward reducing human health risks.
ano.nymous@ccsd.cnrs.fr.invalid (Audrey Bourdin) 03 Apr 2026
https://hal.inrae.fr/hal-05578664v1
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[hal-05698220] Human-to-animal transmission cases of the anthropophilic dermatophyte species Trichophyton tonsurans in France, 2021–2025
Veterinary infections caused by anthropophilic dermatophytes are extremely rare and, until now, have mainly involved Trichophyton rubrum. The present investigation documents 22 cases of positive culture for the anthropophilic dermatophyte species T. tonsurans in companion animals identified in France from 2021 to 2025. Trichophyton tonsurans was isolated from 13 cats and 9 dogs. Eleven animals showed symptomatic infection, whereas the others were asymptomatic carriers. Contamination most likely followed owner-to-animal transmission, suggesting a new route of spread for T. tonsurans, an increasingly reported species. Patients infected with T. tonsurans should therefore be informed of the risk of transmission to their companion animals.
ano.nymous@ccsd.cnrs.fr.invalid (Arnaud Jabet) 20 Jul 2026
https://hal.science/hal-05698220v1
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[hal-05715145] Host–vector microbiome similarity predicts immune-mediated disturbance and vector competence
Vector-borne disease transmission is highly heterogeneous, yet existing models emphasize climate, host density, and pathogen load. We propose that host–vector microbiome similarity represents a previously unrecognized ecological axis in transmission biology. During blood feeding, vectors ingest host-derived immune effectors shaped by the host microbiota. When immune targeting depends on shared microbial features, microbiome similarity predicts the magnitude of immune-mediated disturbance within the vector gut, altering colonization resistance and influencing pathogen establishment. These effects are context-dependent and may enhance or suppress transmission. This framework generates testable predictions linking microbiome similarity, immune-mediated disturbance, and vector competence across systems. Incorporating microbiome similarity into transmission models may help explain heterogeneity and improve ecological understanding and intervention strategies.
ano.nymous@ccsd.cnrs.fr.invalid (Alejandro Cabezas-Cruz) 11 Aug 2026
https://hal.science/hal-05715145v1
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[hal-05715151] The impact of the COVID-19 pandemic on rabies control and health-seeking behavior for postexposure prophylaxis (PEP) in Serbia and North Macedonia and lessons learnt
Abstract Rabies remains a fatal zoonotic disease of significant public health concern, particularly in regions where surveillance and vaccination campaigns are inconsistent. The COVID-19 pandemic disrupted routine healthcare and animal health programs worldwide, raising concerns about the continuity of rabies prevention strategies. This study evaluates the impact of the pandemic on post-exposure prophylaxis (PEP) administration in Serbia and North Macedonia, two Balkan countries historically considered at risk of rabies circulation. We conducted a retrospective analysis of medical records from the Pasteur Institute Novi Sad (PINS, Serbia) and the Clinic for Infectious Diseases in Skopje (CIDS, North Macedonia), comparing pre-pandemic (2018–2019) and post-pandemic (2022–2024) periods. A total of 5,128 patient records were included, with dog bites accounting for the majority of exposures in both countries. Findings revealed a significant increase in PEP administration in North Macedonia, rising from 6.7% to 16.4% of bite patients after the pandemic ( p < 0.001), while Serbia maintained stable rates (0.98% to 1.65%, p > 0.05). Differences likely reflect disparities in rabies surveillance, information flow between veterinary and medical sectors, and the organization of national control programs. These results underscore the importance of integrated One Health approaches and real-time information exchange to optimize rabies prevention and ensure resilience against future disruptions.
ano.nymous@ccsd.cnrs.fr.invalid (Dragana Mijatović) 11 Aug 2026
https://hal.science/hal-05715151v1
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[hal-05673958] Cryptosporidium spp. infections in Tunisia: Epidemiology and public health implications
ABSTRACT Background Cryptosporidiosis is an emerging worldwide zoonosis caused by an opportunistic protozoon, Cryptosporidium spp. In Tunisia, the lack of knowledge on the occurrence and genetic characteristics of Cryptosporidium spp. limits the understanding of its epidemiology, impact and transmission routes. Objectives The present review aims to collect, compile and summarise data on the prevalence of Cryptosporidium spp. infections in humans, animals and the environment contamination in Tunisia. Methods A systematic review was conducted across international databases using PRISMA 2020 Guidelines. Data from 15 selected studies were extracted and organised into thematic categories, including prevalence rates, risk factors, diagnostic methods, and population groups affected. A qualitative synthesis approach was used to analyse and compare findings across studies, highlighting trends, gaps, and public health implications. Results The publications indicate that Cryptosporidium spp. infections are prevalent in both humans and animals, but the results remain confusing and may not reflect the real impact of the disease. In animals, only three studies were conducted in livestock and poultry. Only Cryptosporidium parvum (IIa and IId) was identified in the three studies from adult asymptomatic animals. Therefore, this finding may not reveal the true impact of the parasite on animal health. In humans, all studies were conducted in hospitals on adult and child patients diagnosed with either cancer or immunodeficiency. Cryptosporidium parvum and Cryptosporidium hominis were by far the predominant species suggesting potential zoonotic and anthroponotic transmission routes in humans. Of the two studies conducted on wastewater, five Cryptosporidium species ( C. parvum , C. hominis , Cryptosporidium meleagridis, Cryptosporidium muris, Cryptosporidium andersoni, Cryptosporidium ubiquitum ) and three genotypes were identified, highlighting the potential role of water as a potential route of Cryptosporidium spp. transmission. Conclusions The current review give an overview of the circulating Cryptosporidium spp. species and genotypes but they remain insufficient to fully understand the transmission dynamics, zoonotic potential and animal welfare implications of Cryptosporidium spp. in Tunisia.
ano.nymous@ccsd.cnrs.fr.invalid (Faten Bouaicha) 30 Jun 2026
https://hal.science/hal-05673958v1
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[hal-05715182] Exploration des interactions virus–bactéries chez Ixodes ricinus à l’aide d’un modèle d’infection artificielle
Ixodes ricinus est le principal vecteur européen d’agents pathogènes zoonotiques majeurs affectant la santé humaine et animale, tels que Anaplasma phagocytophilum, Borrelia afzelii et le virus de l’encéphalite à tiques (TBEV). La prévalence de ces agents pathogènes tend à augmenter au sein des populations de tiques, et les co-infections sont fréquemment observées, soulignant la complexité des interactions entre les agents pathogènes au sein du vecteur. Comprendre la dynamique de ces co-infections est donc essentiel et nécessite le développement de modèles expérimentaux fiables permettant l’étude de ces interactions. Afin d’explorer ces interactions, nous avons mis au point des modèles d’infection artificielle chez I. ricinus. La technique de capillary feeding a été utilisée afin d’infecter des nymphes avec deux souches d’A. phagocytophilum (NV2Os et BV49) ainsi qu’avec la souche HYPR du TBEV, dans un premier temps en infections simples. La PCR en temps réel a confirmé la présence d’ARN viral du TBEV dans les nymphes infectées, démontrant l’intérêt de cette technique d’infection pour l’étude des infections virales chez la tique. Concernant A. phagocytophilum, l’ADN et l’ARN bactériens ont été détectés immédiatement après le capillary feeding, confirmant l’acquisition d’A. phagocytophilum par les tiques. En revanche, aucun ADN ni ARN bactérien n’a été détecté chez les nymphes après leur repas sanguin sur des souris, suggérant que la bactérie ne s’est pas répliquée dans les tiques à la fin du repas sanguin. De plus, les adultes issus de ces nymphes infectées artificiellement ont été analysés après la métamorphose. L’ADN d’A. phagocytophilum a été détecté chez certains adultes, indiquant une transmission transstadiale et suggérant une persistance de l’infection. Afin de compléter la compréhension de la dynamique d’infection, des essais de transmission à des hôtes vertébrés non infectés à partir de ces adultes sont actuellement en cours. Ainsi, le capillary feeding constitue une approche prometteuse pour l’étude expérimentale d’agents pathogènes chez la tique. Des ajustements du protocole pour A. phagocytophilum, ainsi que des essais de capillary feeding avec d’autres agents infectieux, pourront permettre, après validation en infections simples, d’envisager l’étude de co-infections. Cette approche offrirait alors de nouvelles perspectives pour mieux comprendre les interactions entre agents pathogènes au sein du vecteur.
ano.nymous@ccsd.cnrs.fr.invalid (Evan Bouton) 11 Aug 2026
https://hal.science/hal-05715182v1
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[hal-05656960] Séquençage short read de nouveaux génomes européens humains et bovins d'Anaplasma phagocytophilum et exploration de sa diversité génétique
Anaplasma phagocytophilum (Aph) est une bactérie zoonotique d’importance médicale et vétérinaire, responsable de l’anaplasmose granulocytaire chez l’être humain et divers animaux domestiques (notamment chiens, chevaux et ruminants). De nombreux animaux de la faune sauvage peuvent également héberger cette bactérie, mais les réservoirs des souches humaines ou de ruminants ne sont pas encore identifiés en Europe. Différentes études épidémiologiques ont mis en évidence une grande diversité génétique d’Aph selon la zone géographique (U.S./Europe), l’espèce hôte et le degré de pathogénicité/virulence. Ces résultats, basées sur le génotypage d’un ou plusieurs gènes ainsi que sur l’analyse comparative de quelques génomes, nécessitent des analyses génomiques complémentaires. Cependant, peu de génomes d’Aph sont actuellement disponibles (34 sur NCBI), et ils ne reflètent pas la diversité réelle de la bactérie, de par leur nombre très réduit et du fait d’une proportion plus importante de génomes américains par rapport aux génomes européens. Notre étude a consisté à obtenir de nouveaux génomes européens d’Aph à l’aide du séquençage short-read par capture avec la technologie Illumina. Quatre assemblages génomiques d’Aph issus de souches humaines et 8 issus de souches bovines ont ainsi été obtenus, doublant le nombre de génomes européens jusqu’alors disponibles. En parallèle, la qualité des 34 génomes d’Aph déjà disponibles sur les bases de données publiques a été évaluée. Trente génomes présentant une qualité et une complétude satisfaisantes ont été conservés tandis que 4 présentaient une contamination importante par des séquences hôtes. Des analyses génomiques comparatives de l’ensemble des génomes (42) ont ensuite été réalisées. L’analyse phylogénétique et l’analyse ANI (average nucleotide identity) ont permis de confirmer la forte divergence entre les souches américaines et européennes ainsi qu’entre les génomes européens d’Aph issus de souches humaines et bovines. Des analyses par continent (Europe/U.S.) du pangénome ont également montré une plus grande diversité des assemblages européens par rapport aux assemblages américains, confirmant les résultats obtenus avec la phylogénie et l’analyse ANI. Le séquençage short read par capture à l’aide de la technologie Illumina de souche d’Aph à partir d’échantillons de terrain, constitue donc une approche très intéressante qui, couplée au séquençage long read Oxford Nanopore Technology, permettra d’obtenir un plus grand nombre de génomes complets européens diversifiés.
ano.nymous@ccsd.cnrs.fr.invalid (Clotilde Rouxel) 15 Jun 2026
https://hal.science/hal-05656960v1
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[hal-05679791] Biothérapie dans la lutte contre Giardia intestinalis: une stratégie One Health prometteuse
Les probiotiques suscitent un intérêt croissant en tant qu’approches innovantes, alternatives ou complémentaires, pour la prévention et la prise en charge des infections intestinales, en réponse aux limites et aux échecs thérapeutiques des traitements antiparasitaires conventionnels, notamment dans le cas de la giardiose, parasitose intestinale fréquente chez l’humain et l’animal. Dans ce contexte, certaines souches bactériennes présentant des propriétés antimicrobiennes spécifiques, susceptibles de contribuer à la lutte contre les infections intestinales, sont activement recherchées. La souche probiotique Lactobacillus johnsonii CNCM I-4884 a ainsi été identifiée par notre équipe pour son activité antagoniste contre Giardia intestinalis. L’activité antiparasitaire de cette souche repose notamment sur ses hydrolases des sels biliaires (BSH). Ces enzymes sont capables de déconjuguer les acides biliaires, générant ainsi des métabolites (acides biliaires déconjuqués), dont certains présentent une toxicité pour le parasite. Afin d’optimiser le potentiel de ce probiotique, cette souche a été soumise à une pression de sélection visant à augmenter son activité BSH, conduisant à l’obtention de dérivés présentant une efficacité accrue in vitro et in vivo contre les formes trophozoïtes du parasite responsables des signes cliniques. Ces résultats confirment que l’ingénierie génétique de bactéries probiotiques, visant à renforcer certaines activités enzymatiques, constitue une piste prometteuse pour le développement de stratégies alternatives ou complémentaires aux traitements antiparasitaires conventionnels. Dans le cadre d’une approche « One Health », le recours à des probiotiques optimisés pourrait contribuer à améliorer la prise en charge des infections intestinales tout en limitant l’émergence de résistances aux traitements antimicrobiens chimiques, aussi bien chez l’humain que chez l’animal.
ano.nymous@ccsd.cnrs.fr.invalid (Damien Oliveira) 03 Jul 2026
https://hal.science/hal-05679791v1
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[hal-05680620] La giardiose du chien : les clés pour une meilleure prise en charge !
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ano.nymous@ccsd.cnrs.fr.invalid (Mohamed Mammeri) 05 Jul 2026
https://enva.hal.science/hal-05680620v1
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[hal-05707341] Active surveillance reveals common SARS-CoV-2 infections among cats and dogs from households with human COVID-19 cases in Texas, USA
Households where people have COVID-19 are high-risk environments for companion animals to become infected by SARS-CoV-2. We sampled 579 pets from 281 households with one or more laboratory-confirmed persons with COVID-19 in central Texas from June 2020 to May 2021. Nineteen out of 396 (4.8%) dogs and 21 out of 157 (13.4%) cats were positive for SARS-CoV-2 by RT-qPCR. Additionally, 95/382 (25%) dogs and 52/146 (36%) cats harbored SARS-CoV-2 neutralizing antibodies. Twenty-six companion animals of ten other species were negative. Overall, 164 (29%) pets were positive for SARS-CoV-2 by molecular and/or serological tests; a total of 110 (39%) out of 281 households had at least one animal with active or past SARS-CoV-2 infection. Cats were more likely to be infected by SARS-CoV-2 and had higher endpoint antibody titers than dogs. We detected 11 SARS-CoV-2 lineages and isolated five of them from dogs and cats, including the B.1.234 lineage that was isolated from a cat a few weeks after the first detection in humans in the United States. Detection of SARS-CoV-2 RNA decreased by 10% per additional day post COVID-19 diagnosis of the human case in the household for both dogs and cats, whereas seropositivity odds increased with each additional day. Human-pet interactions associated with a higher risk of infection in dogs and cats included sleeping in the same room as an infected person, living with multiple infected persons, and sharing food with people. The frequency of clinical signs in pets with active infections did not differ from uninfected ones, suggesting that not all reported signs are attributed to SARS-CoV-2 infection. Characterizing animal infections using active SARS-CoV-2 surveillance in pets at risk of infection may aid in One Health pandemic prevention, response, and management.
ano.nymous@ccsd.cnrs.fr.invalid (Alex Pauvolid-Corrêa) 30 Jul 2026
https://hal.inrae.fr/hal-05707341v1
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[hal-05680587] Nouveauté sur la prise en charge de la trichomonose féline
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ano.nymous@ccsd.cnrs.fr.invalid (Mohamed Mammeri) 05 Jul 2026
https://enva.hal.science/hal-05680587v1
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[hal-05710777] Pathogen surveillance in vectors using high-throughput real-time microfluidic PCRs.
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Sara Moutailler) 04 Aug 2026
https://hal.science/hal-05710777v1
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[hal-05715143] Underrecognized Tick-Borne Encephalitis in Serbia: Evidence from Patients with Suspected West Nile Virus Neuroinvasive Disease
Tick-borne encephalitis (TBE) is an emerging vector-borne disease in Europe, but its epidemiology remains poorly defined in Serbia. In orthoflavivirus-endemic settings, diagnostic challenges may contribute to underrecognition of TBE, particularly among patients with suspected West Nile virus (WNV) infection. We conducted a multicenter retrospective study including patients hospitalized between 2018 and 2023 with suspected WNV neuroinvasive disease or viral encephalitis of unknown etiology. Serum samples were tested for TBEV-neutralizing antibodies using a microneutralization assay. Among 79 patients, TBEV-neutralizing antibodies were detected in four (5.1%). Most reactive cases occurred in patients initially classified as having suspected WNV-associated meningoencephalitis, while TBE had not been considered in the differential diagnosis at admission. These findings suggest that TBE may be underrecognized in Serbia and highlight the importance of confirmatory testing in orthoflavivirus-endemic settings. Strengthening clinical awareness and surveillance will be essential to better define the burden of TBE and inform prevention strategies.
ano.nymous@ccsd.cnrs.fr.invalid (Dragana Mijatović) 11 Aug 2026
https://hal.science/hal-05715143v1
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[hal-05636707] Therapeutic and Preventive Methods for Controlling Cryptosporidiosis in Ruminants
Cryptosporidiosis is a parasitic disease caused by the intestinal protozoa of the genus Cryptosporidium . Curative therapy in animals exhibiting clinical diarrhoea is based on halofuginone lactate or paromomycin sulfate. Preventive measures, which should be prioritised, encompass both a sanitary component — focused on strict hygiene management and adequate colostrum administration — and a medical component involving the use of halofuginone lactate and/or a recently introduced vaccine for passive immunisation of calves. An integrated approach combining both sanitary and medical preventive strategies is strongly recommended.
ano.nymous@ccsd.cnrs.fr.invalid (Faten Bouaicha) 28 May 2026
https://hal.science/hal-05636707v1
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[hal-05630754] Cryptosporidium and Giardia in Côte d’Ivoire: a review within a One Health concept
Background: Cryptosporidium and Giardia are common intestinal protozoa that infect humans, as well as domestic and wild animals. They rank among the most prevalent waterborne parasites and are particularly widespread in developing countries. The advent of molecular diagnostic tools has played a major role in improving our understanding of the transmission of Cryptosporidium spp. and Giardia duodenalis. A thorough understanding of their molecular diversity, geographical distribution, and the environmental and climatic factors that influence their prevalence is essential for effective control in vulnerable populations. However, knowledge about their epidemiology in Africa remains limited. Both parasites negatively impact child growth and development, particularly when affected individuals suffer from aggravating factors, such as malnutrition and HIV. Aim: This review highlights research conducted in Côte d’Ivoire involving humans, animals, and the environment, and emphasizes the importance of the One Health framework. Methods: Relevant publications from March 1990 to December 2024 were sourced from PubMed and ResearchGate. Results: Out of the 26 studies identified, only 9 employed molecular tools and 17 used microscopy tools to detect G. duodenalis and Cryptosporidium spp. Findings confirmed the presence of the parasite in humans, livestock (including cattle, sheep, and camels), and environmental samples (water and soil). The prevalence and genetic diversity of G. duodenalis isolates varied by region and age group in both humans and animals. Conclusions: This study shows that Cryptosporidium and Giardia are widespread in humans and animals in Côte d’Ivoire, with both anthroponotic and zoonotic transmission cycles.
ano.nymous@ccsd.cnrs.fr.invalid (Karim Tuo) 22 May 2026
https://hal.science/hal-05630754v1
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[hal-05630936] Probiotiques de nouvelles génération contre les parasitoses intestinales : une stratégie One Health prometteuse
Les probiotiques suscitent un intérêt croissant en tant qu’approches innovantes, alternatives ou complémentaires, pour la prévention et la prise en charge des infections intestinales, en réponse aux limites et aux échecs thérapeutiques des traitements antiparasitaires conventionnels, notamment dans le cas de la giardiose [1], parasitose intestinale fréquente chez l’humain et l’animal [1-2]. Dans ce contexte, certaines souches bactériennes présentent des propriétés antimicrobiennes spécifiques, susceptibles de contribuer à la lutte contre les infections intestinales, sont activement recherchées. La souche probiotique Lactobacillus johnsonii CNCM I-4884 a ainsi été identifiée par notre équipe pour son activité antagoniste contre Giardia intestinalis, protozoaire responsable de la giardiose. L’activité antiparasitaire de cette souche repose notamment sur ses hydrolases des sels biliaires (BSH). Ces enzymes sont capables de déconjuguer les acides biliaires, générant ainsi des métabolites (acides biliaires déconjuqués), dont certains présentent une toxicité pour le parasite. Afin d’optimiser le potentiel de ce probiotique, cette souche a été soumise à une pression de sélection visant à augmenter son activité BSH, conduisant à l’obtention de dérivés présentant une efficacité accrue in vitro et in vivo contre les formes trophozoïtes du parasite responsables des signes cliniques. Ces résultats confirment que l’ingénierie génétique de bactéries probiotiques, visant à renforcer certaines activités enzymatiques, constitue une piste prometteuse pour le développement de stratégies alternatives ou complémentaires aux traitements antiparasitaires conventionnels. Dans le cadre d’une approche « One Health », le recours à des probiotiques optimisés pourrait contribuer à améliorer la prise en charge des infections intestinales tout en limitant l’émergence de résistances aux traitements antimicrobiens chimiques, aussi bien chez l’humain que chez l’animal.
ano.nymous@ccsd.cnrs.fr.invalid (Damien Oliveira) 22 May 2026
https://hal.science/hal-05630936v1
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[hal-05618590] Tick-borne pathogen diversity and clinical impact of tick-infestation in Serbia and North Macedonia
Ticks and tick-borne pathogens (TBPs) pose an expanding health threat across Europe, yet few studies link tick infection data directly to human clinical outcomes. We conducted a prospective, cross-border "One Health" study in Serbia and North Macedonia to assess the prevalence, diversity, and potential transmission of TBPs from ticks to humans. A total of 133 tick-infested patients were enrolled at two healthcare centers (112 in Skopje, 26 in Novi Sad), and 135 ticks were collected from these individuals, alongside paired blood and serum samples. Overall, TBP DNA was detected in 66.6 % of ticks, with Rickettsia helvetica (25.9 %) and Rickettsia monacensis (12.5 %) were most common. Mixed infections occurred in 15 % of ticks, with up to three pathogens cooccurring. Other detected TBPs included Borrelia afzelii, Borrelia garinii, Borrelia lusitaniae, Anaplasma phagocytophilum, Babesia microti, and Babesia divergens. Four patients (3 %) had detectable pathogen DNA in blood, primarily Rickettsia spp. and Anaplasma spp., yet remained asymptomatic. Most common clinical outcome during the observation period was local hypersensitivity reaction (21.1 %), while α-Gal sensitization was detected in two cases. Phylogenetic analysis revealed Balkan Rickettsia and Borrelia strains were mostly identical to Western and Central European lineages, with a notable exception: a Bo. garinii strain from North Macedonia clustered with strains from Russia and China, indicating possible long-distance introduction. The present study demonstrates that human exposure to multiple TBPs is common and while asymptomatic bloodstream infections do occur, local hypersensitivity reactions are much more common.
ano.nymous@ccsd.cnrs.fr.invalid (Dejan Jakimovski) 11 May 2026
https://hal.science/hal-05618590v1
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[hal-05597815] Phenology of questing Ixodes frontalis nymphs reveals a late-winter to early-spring activity peak
Although Ixodes frontalis is widespread across Europe, including urban and peri‑urban habitats, several aspects of its biology remain undescribed. One such aspect is the population dynamics of its nymphal stage, which has so far been reported from limited sample sizes, preventing the identification of its peak abundance. To fill this knowledge gap, we conducted a year-long monthly survey at four locations in France representing three different “distinct climates”. The sampling protocol - based on the flagging method performed under bamboo bushes - was designed to maximize the likelihood of capturing the nymphal stage. Based on the 400 nymphs collected during this survey, a clear peak of I. frontalis nymphs was observed around March (February to April) across all four sites, with an additional peak in August at one site. The population dynamics of the larval stage—based on semi-quantitative counts—showed the same previously described pattern, with a peak in late autumn. Twenty adults (11 females and 9 males) were also collected from March to December, but these data did not allow a clear identification of a peak abundance. Because several bird species—such as blackbirds, song thrushes, European robins, and Eurasian blackcaps—serve as feeding hosts for both I. ricinus and I. frontalis, and are also reservoirs for pathogens transmitted by these ticks, the implications of our findings for the eco-epidemiology of tick-borne diseases are discussed
ano.nymous@ccsd.cnrs.fr.invalid (Olivier Plantard) 21 Apr 2026
https://hal.inrae.fr/hal-05597815v1
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[hal-05707256] Structure-based design of new pyrazole inhibitors targeting Plasmodium falciparum dihydroorotate dehydrogenase (PfDHODH)
Malaria remains one of the world's most devastating parasitic diseases, with increasing resistance to current therapies highlighting the need for new antimalarial agents with novel mechanisms of action. Plasmodium falciparum dihydroorotate dehydrogenase (PfDHODH), a key enzyme in pyrimidine biosynthesis, represents a validated molecular target for antimalarial drug discovery. In this study, a structure-based optimization strategy was applied to a previously identified hydroxypyrazole hit compound to design, synthesize, and evaluate new derivatives as selective PfDHODH inhibitors. Through three iterative rounds of rational design, we identified several analogs with notable PfDHODH activity and, in some cases, selectivity over the human isoform (SI > 30). X-ray crystallographic studies of PfDHODH in complex with the most active inhibitors confirmed their predicted binding modes and demonstrated the enzyme's ability to accommodate bulky hydrophobic substituents. The best compounds, notably derivatives 6, 7, 12, 13 and 22, exhibited low micromolar enzymatic inhibition (IC 50 values from 1.3 to 5.9 μM), favourable physicochemical properties (PBS solubility 0.03 -2.8 mM, logD 7.4 0.25 -1.7), and antiparasitic activity in P. falciparum 3D7 cultures (EC 50 values from 15 to 22 μM), with negligible cytotoxicity in mammalian cells (CC 50 > 150 μM except for compound 22). While these hydroxypyrazole-based scaffolds have poor antiplasmodial activity, this study provides structure activity relationship data that may be useful for the development of next-generation PfDHODH inhibitors for malaria chemoprevention and treatment.
ano.nymous@ccsd.cnrs.fr.invalid (Agnese C Pippione) 30 Jul 2026
https://hal.inrae.fr/hal-05707256v1
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[hal-05618701] Consultations in general practice related to a tick bite episode in mainland France in 2023–2024
Abstract Background The emergence and spread of TBDs present major challenges. Exposure to tick bites in mainland France is mainly documented through local studies or citizen science projects. According to the 2024 French national survey, about 15% bitten individuals consult a healthcare professional. National-level data from general practice are needed to better describe tick bite epidemiology. Main objective To estimate the incidence of patients consulting general practitioners (GPs) for a tick bite and to describe their characteristics, their management and the context of the bite. Method We conducted a study using the French Sentinelles network, a national surveillance system that collects data from a sample of GPs. From May 2023 to April 2024, an indicator ‘Consultations with a tick bite’ was added to the routine data collection, in addition to the ongoing Lyme borreliosis surveillance. National and regional incidences were estimated using a hierarchical Bayesian model incorporating spatial and temporal dependencies to account for data sparsity. A tick collection was also carried out in order to identify the ticks and analyse the pathogens they might transmit. Results A total of 179 GPs participated and reported 483 consultations for a tick bite episode. The estimated national incidence was 324 cases per 100,000 population (95% CI [290; 369]) over the study period, peaking in May-June 2023. Incidence was highest in the southwestern and northeastern France. Children represented one quarter of cases and nearly half of patients consulted in general practice without clinical symptoms. Of the 86 ticks analysed, 24% tested positive for at least one of the pathogens tested. Conclusion These findings provide new insights into the epidemiology of tick bites in France and contribute to assessing population exposure to ticks, informing future prevention and public health strategies.
ano.nymous@ccsd.cnrs.fr.invalid (Camille Bonnet) 11 May 2026
https://hal.science/hal-05618701v1
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[hal-05706994] Le lion de l’Atlas face aux parasites : première investigation du parasitisme interne et externe au Jardin zoologique national de Rabat
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ano.nymous@ccsd.cnrs.fr.invalid (Salma Bouziane) 30 Jul 2026
https://hal.science/hal-05706994v1
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[hal-05619102] Aminopyrimidine-thioethers targeting trypanothione reductase show in vitro and in vivo activity against Leishmania donovani
Leishmaniases are neglected tropical diseases caused by Leishmania parasites and recognized by the WHO. Current chemotherapy remains limited due to toxicity and the emergence of drug resistance, highlighting the need for new therapeutic strategies. Trypanothione reductase (TryR), a key enzyme involved in the parasite redox metabolism, represents an attractive target due to its essential role and absence in mammalian hosts. In the search for novel antileishmanial agents, we synthesized a library of thio-linked pyrimidine derivatives using the Buchwald–Hartwig methodology. Thirteen aminopyrimidine-thioethers were evaluated for their in vitro activity against Leishmania donovani axenic and intramacrophage amastigotes, as well as their cytotoxicity in RAW 264.7 cells. Among them, compounds 6, 13 and 15 exhibited potent activity against intracellular amastigotes with IC50 values of 4.3 μM, 0.7 μM and 1.4 μM, respectively. To investigate their mechanism of action, IC50 assays were performed in the presence of TryR antisense constructs. Confocal microscopy and fluorescent probes were used to assess cellular alterations. The compounds induced increased ROS production and a decrease in mitochondrial membrane potential (ΔΨm), confirmed by JC-1 assays, suggesting mitochondrial dysfunction. In vivo toxicity studies were subsequently conducted for the three most active compounds. Compound 13 showed no significant toxicity and was further evaluated in L. donovani-infected BALB/c mice at doses of 10, 1 and 0.1 mg/kg. Treatment significantly reduced parasite burden at doses of 0.1–1 mg/kg, while preserving hepatic, renal, muscular and metabolic parameters. Overall, these results highlight aminopyrimidine-thioethers as promising antileishmanial candidates, with compound 13 demonstrating a favorable therapeutic profile both in vitro and in vivo.
ano.nymous@ccsd.cnrs.fr.invalid (Sandrine Cojean) 11 May 2026
https://hal.science/hal-05619102v1
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[hal-05619096] Résistance médicamenteuse et coût biologique associé chez Leishmania infantum sélectionnée sous pression médicamenteuse in vitro
Leishmania infantum est l’agent principal de la leishmaniose viscérale zoonotique dans le bassin méditerranéen, le chien constituant le principal réservoir de l’infection humaine. Les options thérapeutiques restent limitées. Chez l’homme, le traitement repose principalement sur l’amphotéricine B liposomale, tandis que chez le chien la prise en charge repose généralement sur les antimoniés associés à l’allopurinol ou à la miltéfosine. Dans ce contexte, l’émergence de souches résistantes représente une préoccupation croissante en santé humaine et vétérinaire. Dans cette étude, nous avons évalué les conséquences biologiques de la résistance médicamenteuse chez Leishmania infantum après sélection in vitro sous pression discontinue. La souche étudiée provient d’un isolat canin sensible obtenu auprès du Centre National de Référence (CNR) Leishmania. Cet isolat a été exposé à des concentrations croissantes de tartrate d’antimoine et de potassium (SbIII) ou d’allopurinol afin de sélectionner trois lignées résistantes : une souche résistante aux antimoniés (SbR), une souche résistante à l’allopurinol (AlloR) et une souche double résistante (SbR/AlloR). Ces souches ont été comparées à la souche sauvage (WT) par l’analyse de leur cinétique de croissance, de leur sensibilité médicamenteuse (CI50) et de leurs caractéristiques morphométriques. Les souches résistantes présentent un retard dans l’apparition de la phase exponentielle et une densité parasitaire maximale plus faible que la souche WT, suggérant un coût biologique associé à l’acquisition de la résistance. Les tests de chimiosensibilité confirment les phénotypes résistants et mettent en évidence des phénomènes de résistances croisées pour certains composés. Des variations dans la proportion de promastigotes métacycliques ont également été observées entre les différentes souches. Ces lignées résistantes constitueront des modèles expérimentaux utiles pour étudier les mécanismes et la transmission potentielle de la résistance chez L. infantum dans une approche One Health, notamment pour comparer et caractériser la résistance au sein d’isolats cliniques canins, humains ou vectoriels et de son potentiel de transmission à ces différents acteurs.
ano.nymous@ccsd.cnrs.fr.invalid (Sandrine Cojean) 11 May 2026
https://hal.science/hal-05619096v1
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[hal-05630920] Giardia duodenalis en Algérie : enjeux zoonotiques et implications pour la santé publique dans une approche « One Health »
Giardia duodenalis est un protozoaire parasite qui infecte principalement l’intestin grêle de nombreux mammifères, y compris l’être humain. Il s’agit d’un complexe d’espèces composé de plusieurs génotypes appelés assemblages, classés de A à H. Parmi eux, les assemblages A et B sont considérés comme les plus zoonotiques, c’est-à-dire qu’ils peuvent être transmis entre les animaux et l’homme et représentent donc un risque important pour la santé publique. Malgré son importance sanitaire, les connaissances sur la présence et les caractéristiques génétiques de ce parasite en Algérie restent limitées. Le manque de données épidémiologiques rend difficile l’évaluation précise de son impact sur la santé humaine et animale, ainsi que l’estimation de son potentiel zoonotique. Cette revue a pour objectif de synthétiser les travaux scientifiques réalisés en Algérie concernant la présence de G. duodenalis chez l’homme, les animaux et dans l’environnement, en adoptant une approche « One Health ». Cette approche reconnaît l’interconnexion entre la santé humaine, la santé animale et l’état de l’environnement. Pour cela, les bases de données PubMed et ResearchGate ont été consultées afin d’identifier les publications traitant de G. duodenalis en Algérie entre janvier 2000 et mars 2026. Au total, 18 publications pertinentes ont été identifiées. Cependant, seulement cinq études ont utilisé des outils de biologie moléculaire pour caractériser génétiquement les isolats de G. duodenalis. Les résultats disponibles indiquent la présence du parasite chez l’être humain, chez plusieurs espèces de bétail, notamment les bovins, les ovins et les dromadaires, ainsi que dans l’environnement, à travers des échantillons d’eau et de sol. Les taux de prévalence et la diversité génétique des isolats varient selon les régions étudiées et selon les groupes d’âge, tant chez les humains que chez les animaux. L’assemblage A a été fréquemment identifié chez les humains et chez les animaux, ce qui suggère l’existence possible d’une transmission zoonotique. Néanmoins, les données restent encore insuffisantes pour comprendre précisément les voies de transmission du parasite en Algérie. Des recherches supplémentaires sont donc nécessaires afin de mieux comprendre la dynamique de transmission, le potentiel zoonotique et les conséquences de G. duodenalis sur la santé publique et le bien-être animal. Une collaboration étroite entre les professionnels de la santé est essentielle dans le cadre de l’approche « One Health ».
ano.nymous@ccsd.cnrs.fr.invalid (Myriam Thomas) 22 May 2026
https://hal.science/hal-05630920v1
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[hal-05706991] Première Identification d’une population de Parascaris spp. résistante au pyrantel chez des poulains en France
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ano.nymous@ccsd.cnrs.fr.invalid (Kenza Bourrier) 30 Jul 2026
https://hal.science/hal-05706991v1
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[hal-05630841] Etude des vésicules extra-cellulaires de Trichinella spp et de leur potentiel immunomodulateur
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ano.nymous@ccsd.cnrs.fr.invalid (Jana Dhaybi) 22 May 2026
https://hal.science/hal-05630841v1
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[hal-05634970] Obtention d’un nouvel outil cellulaire pour l’étude des interactions spécifiques entre Toxoplasma gondii et son hôte définitif félin : les organoïdes intestinaux.
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Julie Rouzet) 27 May 2026
https://hal.science/hal-05634970v1
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[hal-05627134] Analyse épidémiologique, clinique et moléculaire des hémosporidioses chez des rapaces et corvidés accueillis dans un centre de soins d’Ile de France
L’impact des infections par les hémosporidies chez les oiseaux accueillis en centres de soins demeure largement méconnu. Cette étude a pour objectif la détermination de la prévalence et les facteurs de risque associés à l’admission de rapaces et de corvidés infectés dans un centre de soins de la région parisienne. En évaluant leurs chances de rétablissement et de relâcher, ainsi que les risques de transmission aux autres oiseaux hospitalisés, ce travail permet de proposer des mesures sanitaires adaptées aux structures de réhabilitation de la faune sauvage. Des prélèvements sanguins ont été réalisés sur 37 rapaces appartenant à 6 espèces et 150 corvidés issus de 4 espèces lors de leur arrivée à l’hôpital de la faune sauvage de l’École nationale vétérinaire d’Alfort (CHUV-FS, EnvA). L’identification des hémosporidies et l’estimation de la parasitémie ont été effectuées par l’analyse de frottis sanguins. Par la suite, les prélèvements positifs ont été analysés par PCR et séquençage afin d’assurer une identification moléculaire précise des parasites. Les analyses ont confirmé la présence des genres Haemoproteus, Leucocytozoon et Plasmodium. Les résultats statistiques ont mis en évidence une association significative entre l’âge des individus et l’infection par Plasmodium sp. Ce dernier s’est révélé prédominant chez les corvidés et plus fréquemment impliqué dans les cas de co-infestations, tandis que le genre Leucocytozoon semble plus prévalent chez les rapaces. Enfin, l’étude souligne qu’aucun impact significatif de ces infections n’a été observé sur le succès final du relâcher des oiseaux.
ano.nymous@ccsd.cnrs.fr.invalid (Veronica Risco-Castillo) 20 May 2026
https://hal.science/hal-05627134v1
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[hal-05630924] Première identification moléculaire de Cryptosporidium spp. et Giardia duodenalis chez les pigeons en France : implications dans l’approche One Health.
Les pigeons (Columba livia domestica et Columba palumbus) sont des espèces ubiquistes présentes dans les villes du monde entier. Leur interaction avec les humains, les animaux domestiques et les oiseaux sauvages en fait des porteurs potentiels d’agents pathogènes transmissibles, notamment des parasites zoonotiques. L’objectif de cette étude était d’identifier des protozoaires appartenant aux genres Cryptosporidium et Giardia chez ces deux espèces de pigeons hébergées au Centre Hospitalier Universitaire Vétérinaire de la Faune Sauvage (CHUVFS) de l’École nationale vétérinaire d’Alfort, en France. Des échantillons fécaux provenant de 371 pigeons (Columba livia et Columba palumbus), dont une large majorité de juvéniles, ont été collectés et analysés à l’aide de l’immunofluorescence directe ainsi que des techniques d’identification moléculaire (PCR 18S rRNA et gp60). Quatre-vingt-six et douze échantillons fécaux se sont révélés positifs respectivement pour Cryptosporidium spp. et Giardia spp. par immunofluorescence. Les jeunes pigeons semblaient être infectés par Cryptosporidium spp. plus fréquemment que les adultes. De plus, les pigeons ramiers semblaient être plus souvent infectés par Giardia spp., tandis que les pigeons bisets présentaient une prévalence plus élevée de Cryptosporidium spp. L’analyse moléculaire a révélé la présence d’espèces zoonotiques, notamment Cryptosporidium meleagridis, Cryptosporidium parvum et Giardia duodenalis assemblage B. Étant donné que ces espèces sont connues pour infecter l’être humain, les pigeons pourraient représenter une source potentielle de transmission zoonotique.
ano.nymous@ccsd.cnrs.fr.invalid (Anaïs Devulder) 22 May 2026
https://hal.science/hal-05630924v1
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[hal-05631013] Muscarinic Receptors Signalling in the Regulation of Tick Salivation
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ano.nymous@ccsd.cnrs.fr.invalid (Caina Ning) 22 May 2026
https://hal.inrae.fr/hal-05631013v1
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[hal-05619594] Stomoxys calcitrans as a potential mechanical vector of Anaplasma phagocytophilum : assessment through original ex vivo feeding models
Granulocytic anaplasmosis is a zoonotic disease that affects various domestic mammals (dogs, horses, and, more rarely, cats). In ruminants, it is better known as tick-borne fever (TBF) and is responsible for significant economic losses on European livestock farms, mainly due to a drop in milk production, abortions, and immunosuppression, which can lead to secondary infections. The disease is caused by the strictly intracellular bacterium Anaplasma phagocytophilum , whose biological vectors are ticks of the genus Ixodes . Other blood-feeding arthropods may be involved in transmitting this bacterium, notably Stomoxys calcitrans , a major ectoparasite of livestock that is implicated in transmitting other pathogens, including bacteria of the genus Anaplasma . This study aimed to evaluate the potential of S. calcitrans to act as a mechanical vector of A. phagocytophilum under laboratory conditions. Two experimental models were employed: one mimicking immediate transmission, and the other delayed transmission. In both models, A. phagocytophilum DNA and RNA were detected in S. calcitrans for the first time, but no traces of the bacterium’s DNA or RNA were found in the glass feeder’s blood. Further research is needed to confirm these findings through field studies investigating the presence of the bacterium in flies under natural conditions. This study also describes two original infection models of stable flies designed to reproduce their ex vivo blood-feeding, promoting alternative experimental approaches in accordance with animal welfare regulations and 4R principles.
ano.nymous@ccsd.cnrs.fr.invalid (Clotilde Rouxel) 12 May 2026
https://hal.science/hal-05619594v1
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[hal-05618589] Ecological Frameworks of Pathogen–Pathogen and Pathogen–Microbiome Interactions Within the Tick Holobiont
Ticks harbor complex microbial communities composed of symbionts, commensals, and tick-borne pathogens (TBPs). Together, these microorganisms form the tick holobiont. Within this system, the tick’s physiological architecture structures microbial communities by distributing microorganisms across distinct tissues. This compartmentalization creates spatially distinct ecological niches, which in turn shape how microbial communities assemble and interact. In this review, we integrate ecological theory with current knowledge of tick microbiome research to examine how pathogen–pathogen and pathogen–microbiome interactions emerge within these tissue-structured microbial communities. We first outline how baseline ecological filters, including tick species, developmental stage, tissue identity, vertical transmission, and environmental context, shape the microbiome configuration through community assembly processes. We then examined how TBPs, as high-impact colonizers, can further modify microbial networks by altering host-mediated selective pressures, influencing interaction topology, and reshaping community stability. Based on these observations, we propose a dual selective pressure framework in which (i) baseline ecological structuring processes and (ii) pathogen-associated selective pressures interact to determine the microbial network configuration and functional outcomes within the tick holobiont. These interacting forces may drive shifts in diversity, modularity, keystone taxa emergence, and network resilience, ultimately influencing vector competence. This review frames the microbial communities within the tick holobiont as spatially structured ecological systems shaped by multilevel selective pressures. This conceptual foundation provides a coherent framework for understanding microbial interactions in arthropod vectors and highlights avenues for mechanistic research and microbiome-based strategies to mitigate tick-borne diseases.
ano.nymous@ccsd.cnrs.fr.invalid (Elianne Piloto-Sardiñas) 11 May 2026
https://hal.science/hal-05618589v1
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[hal-05651852] Introduced or established? Convergent evidence indicates imported pine wood nematode vectors occupy gaps in native distribution
<div><p>Monitoring regulated quarantine plant pathogens and, when relevant, their vectors is compulsory in the European Union. Local Monochamus species (Coleoptera, Cerambycidae) vector the pine wood nematode, Bursaphelenchus xylophilus, a non-native pest already established in most of Portugal. Only 29 M. galloprovincialis individuals were trapped in Belgium in ten years (2013-2022), despite a dense coverage of pheromone-baited traps, suggesting absence or a very rare local occurrence in the country. In the northern neighbouring countries, only one single established population is known in The Netherlands and one in Denmark. A species distribution model based on pheromone-trap catches (negative and positive) of M. galloprovincialis from 4,914 traps in 29 European countries between 2008 and 2019 was developed, using the overall climate conditions and the distribution of seven pine tree species as explanatory variables. The effect of spatial scale was tested with a multi-scale approach. With a 225*225 km spatial grain, the major explanatory variables were the mean diurnal temperature range and, to a lesser extent, the presence of Pinus spp. The model predicted a low probability of presence in Belgium, the Netherlands, Great Britain and north-western Germany compared to southern Europe. Genotyping allowed to conclude that at least some of the beetles caught in Belgium originated from foreign locations. All catches were located close to entry points, suggesting introduction with imported material. The small size of most of the Belgian pine stands may also explain the absence or apparently transient status, or rareness of Monochamus spp. This study thus suggests that surveys in Belgium should privilege entry points rather than local forest stands.</p></div>
ano.nymous@ccsd.cnrs.fr.invalid (Jean-Claude Grégoire) 10 Jun 2026
https://hal.inrae.fr/hal-05651852v1
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[hal-05618689] A Bayesian modelling framework for estimating tick-borne pathogen transmission dynamics at the host-tick interface
Understanding the transmission dynamics of tick-borne pathogens at the host-tick interface is challenged by the presence of multiple pathways for tick infection, including (i) host-to-tick transmission, (ii) tick-to-tick (cofeeding) transmission, and (iii) pre-existing infection through vertical transmission or prior feeding. Assessing parameters governing these pathways is critical for identifying the main transmission drivers and, consequently, key prevention and control points. Here, we developed a Bayesian modelling framework that estimates key parameters describing the probability of each transmission pathway and assesses associated factors, including bird species, tick life stage and engorgement level, by jointly modelling transmission at the host-tick interface using data collected in field studies that sample hosts and their ticks. First, by fitting the model to simulated host-tick infection data, we demonstrated the framework’s ability to recover the parameter values underlying these data. Model performance improved significantly when more information was available on variability in cofeeding probability among individual ticks, highlighting the value of testing all collected ticks and recording their spatial distribution on the host in relation to each other. Second, we fitted the model to field data collected at the bird-tick interface in Northeast France in 2023, focusing on Borrelia garinii , B. valaisiana , and Anaplasma phagocytophilum as case pathogens. For all three pathogens studied, models including cofeeding transmission explained the data significantly better than models that did not. Engorgement level was significantly and positively associated with the probability of bird-to-tick transmission for A. phagocytophilum . Finally, the estimated parameters, such as the probability of A. phagocytophilum infection in birds and the probability of Borrelia or Anaplasma infection in ticks before feeding, were comparable to values from an external dataset, not used for model fitting. Our framework provides a valuable foundation for future research to understand tick-borne pathogen transmission dynamics based on epidemiological and ecological field data collected at the host-tick interface.
ano.nymous@ccsd.cnrs.fr.invalid (Younjung Kim) 11 May 2026
https://hal.science/hal-05618689v1
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[hal-05551639] Yeast probiotic protects gut microbiota diversity and metabolic potential against Cryptosporidiosis-induced disruption in goat kids
Cryptosporidiosis, caused by Cryptosporidium parvum, is a major cause of enteric disease and gut microbiota disruption in neonatal ruminants. It can lead to impaired growth, increased susceptibility to pathogens, and longterm gut dysfunction. In this study, we investigated whether supplementation with a live yeast probiotic (Saccharomyces cerevisiae Sc47) could help preserve gut microbiota resilience and functional homeostasis during an experimental C. parvum oral infection in goat kids. Thirty male French Alpine goat kids were assigned to three groups: uninfected control (healthy), infected, and infected with yeast supplementation. Longitudinal 16S rRNA gene sequencing, network analysis, and functional metagenomic predictions were used to assess microbial diversity, community composition, co-occurrence patterns, and metabolic potential, with a focus on short-chain fatty acid (SCFA) biosynthesis. Infection induced marked dysbiosis, characterised by a substantial reduction in microbial richness and a widespread loss of SCFA-producing commensals and metabolic functions. In contrast, yeast supplementation significantly reduced oocyst excretion by more than 84% throughout the experiment, attenuated pathogen-induced community shifts, and maintained beneficial genera such as Butyricicoccus and members of the Oscillospiraceae family. Furthermore, network analysis revealed that probiotic treatment preserved microbial association structures and reduced community fragmentation. Consistent with these findings, functional profiling showed the retention of pathways involved in carbohydrate metabolism, amino acid biosynthesis, and SCFA production, suggesting enhanced microbiota resilience. These findings demonstrate that S. cerevisiae supplementation can mitigate infection-associated dysbiosis by controlling pathogenic overgrowth while sustaining commensal bacterial stability and functional capacity. This highlights its potential as a microbiota-targeted strategy to support gut health in neonatal ruminants.
ano.nymous@ccsd.cnrs.fr.invalid (Mohamed Mammeri) 22 May 2026
https://hal.science/hal-05551639v1
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[anses-05586225] A novel RFLP-PCR method for the rapid diagnosis of Echinococcus multilocularis and different Echinococcus granulosus sensu lato species from tissue samples
Both alveolar echinococcosis and cystic echinococcosis are zoonotic diseases affecting thousands of humans in Europe annually. Five Echinococcus species are known to be endemic in Europe, but with varying relative importance in humans and animals. In order to identify these Echinococcus species from tissue samples, an RFLP-PCR method was developed and validated in accordance with the French quality standards for molecular diagnostics (NF U47-600-2). Amplification by PCR of about 846 bp from the 12S ribosomal RNA gene was followed by a single digestion step with three restriction enzymes (AccI, DdeI and HinfI). The RFLP-PCR method distinguishes Echinococcus multilocularis , E. granulosus sensu stricto , E. equinus , E. ortleppi and E. canadensis in six specific profiles composed of two or three bands. Each profile is specific for the species, except an additional specific profile from genotype G8 of E. canadensis. Species from other genera of the Taeniidae family correspond to two other types of profiles. Additionally, in silico analyses predicted three specific additional profiles for the other four Echinococcus species. The limit of detection of the method including DNA extraction is estimated to be a minimum of 1,000 copies. Total specificity and sensitivity were obtained by testing a panel of 73 and 79 DNA samples previously identified by sequencing. This RFLP-PCR technique is cost-effective, simple and rapid to implement, making it suitable for use in large epidemiological studies, as well as for single diagnostic purposes targeting tissue samples, such as cysts or worms, without requiring sequencing.
ano.nymous@ccsd.cnrs.fr.invalid (Gérald Umhang) 09 Apr 2026
https://anses.hal.science/anses-05586225v1
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[hal-05630823] Evaluation of Trichinella’s extracellular vesicules involvement in the interactions with the host.
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ano.nymous@ccsd.cnrs.fr.invalid (Jana Dhaybi) 22 May 2026
https://hal.science/hal-05630823v1
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[hal-05630749] La giardiose chez les animaux de production
Giardiasis is an intestinal infection caused by a protozoan parasite, commonly affecting young production animals, including calves, goat kids, and lambs. Often asymptomatic or responsible for mild digestive signs, it can impair growth and reduce farm profitability. The parasite alternates between trophozoite and cyst stages, with the latter ensuring fecal–oral transmission. Genotypes, known as assemblages, exhibit variable host specificity, with assemblage E predominating in ruminants and pigs. Diagnosis relies on coproscopy, direct immunofluorescence assays, or PCR. No treatment is officially authorised in France, although fenbendazole and albendazole have proven efficacy. Prevention primarily depends on strict hygiene measures. Giardiasis is also a potential zoonosis, although strains found in livestock rarely pose a risk to humans. A management strategy, combining detection, rational treatment, and biosecurity, can help mitigate its impacts.
ano.nymous@ccsd.cnrs.fr.invalid (Mohamed Mammeri) 22 May 2026
https://hal.science/hal-05630749v1
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[hal-05569061] Méthodes de diagnostic de l’infection par Cryptosporidium spp. chez les ruminants: connaissances actuelles et tendances futurs
La cryptosporidiose est une maladie parasitaire largement répandue dans le monde, fréquemment responsable d’épidémies d’origine hydrique et alimentaire. Les progrès en biologie moléculaire ont permis d’améliorer la compréhension des modes de transmission de Cryptosporidium , notamment de sa dimension zoonotique. Ces outils occupent aujourd’hui une place centrale dans la surveillance de la maladie dans les pays industrialisés. Bien que le diagnostic repose encore principalement sur l’observation microscopique, les méthodes moléculaires, en particulier la PCR et le séquençage, se développent rapidement. Elles offrent un diagnostic plus précis et permettent une meilleure caractérisation des espèces impliquées, contribuant ainsi à une meilleure compréhension de l’épidémiologie et des voies de contamination de la cryptosporidiose.
ano.nymous@ccsd.cnrs.fr.invalid (Faten Bouaicha) 26 Mar 2026
https://hal.science/hal-05569061v1
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[hal-05630788] Bafilomycin A1 is a promising therapeutic agent against T. spiralis infection by inhibiting the heme-transporting ATP6V0C/HRG-1 complex
Trichinella spiralis ( T. spiralis ), a zoonotic nematode that causes severe myositis and systemic morbidity, sustains chronic muscle parasitism through evolutionary adaptations; however, this globally prevalent disease lacks targeted therapies to disrupt chronic infection. Although the heme transport protein HRG-1 has been characterized as an intervention target in free-living species (e.g., Caenorhabditis elegans ) and hematophagous parasites (e.g., Haemonchus contortus ), the molecular machinery governing heme acquisition in the nonhematophagous parasite T. spiralis remains uncharacterized, and no drugs targeting HRG-1 have been reported until now. Herein, we demonstrate that T. spiralis , a parasite that lacks the ability to synthesize heme autonomously, has evolved a sophisticated mechanism to scavenge and utilize heme from its host. By employing an aspartic protease to degrade host hemoglobin and myoglobin in the parasitic niche, T. spiralis is able to liberate heme for its own growth and survival. The structurally and functionally conserved Ts -HRG-1 protein plays a key role in transporting heme to the entire worm, particularly to functional organs, such as the cuticle and stichosome. More importantly, we discovered that the interaction between Ts -HRG-1 and Ts -ATP6V0C results in the formation of a functional complex that is essential for the parasite’s heme acquisition. The intervention effect achieved by Ts -ATP6V0C RNAi or inhibiting the activity of Ts -ATP6V0C with bafilomycin A1 (BafA1) was consistent with Ts -HRG-1 RNAi, resulting in impaired heme uptake, developmental arrest and a reduced larval burden in mouse hosts. These findings enhance our understanding of the parasite’s heme acquisition mechanism and identify the development of drugs that target proteins that interact with HRG-1 as a new direction in anthelminthic drug research.
ano.nymous@ccsd.cnrs.fr.invalid (Yushu He) 22 May 2026
https://hal.science/hal-05630788v1
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[hal-05630917] Biothérapies à base d’hydrolases des sels biliaires dans la lutte contre la giardiose
La giardiose est une parasitose intes&gt;nale causée par le protozoaire Giardia intesPnalis. L’infec&gt;on, transmise par voie fécale-orale, peut provoquer des diges&gt;fs chroniques, comme le syndrome de l’intes&gt;n irritable (SII) chez l’humain ou des retards de développement chez l’enfant. Malgré les traitements an&gt;parasitaires disponibles, notamment les dérivés nitroimidazolés, des limites persistent, en par&gt;culier l’émergence de résistances associée à des échecs thérapeu&gt;ques. Le développement de stratégies alterna&gt;ves ou complémentaires à la chimiothérapie an&gt;parasitaire classique apparaît nécessaire (1). Ainsi, la souche Lactobacillus johnsonii CNCM I-4884 a été sélec&gt;onnée comme souche probio&gt;que possédant une ac&gt;vité an&gt;-Giardia in vitro et in vivo (1-2). Ce\e souche inhibe la croissance de G. intesPnalis via ses ac&gt;vités enzyma&gt;ques d’hydrolases des sels biliaires (BSH), qui conver&gt;ssent les acides biliaires conjugués présents dans la bile, en acides biliaires déconjugués dont certains sont toxiques pour le parasite. Afin de valider le rôle central des BSH dans le contrôle de Giardia, ce\e bactérie probio&gt;que a été placée à une pression de sélec&gt;on visant à augmenter son ac&gt;vité BSH ; les dérivés obtenus se sont alors révélés plus efficaces contre le parasite. Aussi, nous avons modifié géné&gt;quement la souche sauvage de Lj CNCM-I-4884 afin de surexprimer l’une et/ou l’autre de ses deux BSHs (BSH405, BSH1011, ou les deux simultanément). Enfin, les souches dérivées (la souche issue de la pression de sélec&gt;on et les deux souches géné&gt;quement modifiées) ont significa&gt;vement réduite la croissance in vitro des trophozoïtes de G. intesPnalis, par rapport à la souche sauvage Lj CNCM-I-4884. Ces données suggèrent que l’u&gt;lisa&gt;on de bactéries sélec&gt;onnées ou géné&gt;quement modifiées pour surexprimer des ac&gt;vités BSH pourraient cons&gt;tuer une approche innovante dans la lu\e contre la giardiose, soit en tant qu’alterna&gt;ve, soit en complément des traitements an&gt;parasitaires existants. A terme, ce type de stratégie pourrait contribuer à réduire les problèmes de résistance et à améliorer la prise en charge des infec&gt;ons parasitaires intes&gt;nales. References: (1) Allain T.; Chaouch S.; Thomas M.; Travers M.-A.; Valle I.; Langella P.; Grellier P.; Polack B.; Florent I.; Bermudez-Humaran L.G. Bile Salt Hydrolase AcRviRes: A Novel Target to Screen AnR-Giardia Lactobacilli? Front. Microbiol., 2018. 9, 89. hWps://doi.org/10.3389/fmicb.2018.00089 (2) Boucard A.-S.; Florent I.; Polack B.; Langella P.; Bermudez-Humaran L.G. Genome Sequence and Assessment of Safety and PotenRal ProbioRc Traits of Lactobacillus johnsonii CNCM I-4884. Microorganisms, 2022. 10(2), 273. hWps://doi.org/10.3390/microorganisms10020273
ano.nymous@ccsd.cnrs.fr.invalid (Damien Oliveira) 22 May 2026
https://hal.science/hal-05630917v1
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[hal-05619073] Exploration des interactions virus-bactéries chez Ixodes ricinus à l'aide d'un modèle d'infection artificielle
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ano.nymous@ccsd.cnrs.fr.invalid (Evan Bouton) 11 May 2026
https://hal.science/hal-05619073v1
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[hal-05543411] Optimiser la production du génome d'Anaplasma phagocytophilum, une étape cruciale pour comprendre la virulence et le tropisme d'hôte
Anaplasma phagocytophilum (Aph) est une bactérie intracellulaire stricte transmise par les tiques du genre Ixodes, responsable de l’anaplasmose granulocytaire chez l’Homme et les ruminants. La variabilité de la virulence et la diversité des hôtes suggèrent une diversité génétique encore mal caractérisée. L’analyse génomique d’Aph demeure complexe en raison de la difficulté à isoler et cultiver la bactérie, ainsi qu’à séparer son ADN de celui de l’hôte vertébré. Ce projet vise (i) à évaluer la qualité des génomes disponibles dans les bases publiques et (ii) à développer une stratégie de séquençage long-read Oxford Nanopore Technologies (ONT®) permettant d’obtenir des génomes complets et d’origine plus diversifiée. En 2025, nous avons évalué 33 génomes Aph disponibles sur NCBI pour leur fragmentation, leur taille (QUAST) et leur pureté (BLAST, Kraken2). Vingt-neuf présentaient une qualité et une complétude satisfaisantes, tandis que 4 présentaient une contamination importante par des séquences hôtes. Un séquençage ONT d’une souche de source humaine enrichie en culture a permis d’obtenir, après sous-échantillonnage d’une profondeur de séquençage de 100X, un génome complet en un seul contig (~1,5 Mb). Des simulations de profondeurs variables (10X à 100X, 10 réplicas) ont montré qu’une couverture de 30X permettait l’assemblage d’un génome complet équivalent au contrôle. Nous avons également mis en évidence qu’à 20X les génomes étaient de taille attendue malgré une fragmentation plus importante (&gt;5 contigs), et qu’à 10X le génome était fragmenté et incomplet. Les analyses de clustering par k-mer ont révélé que dès 20X, les topologies d’arbre étaient stables, indiquant que cette profondeur est suffisante pour des comparaisons robustes de génomes. Des essais de séquençage réel utilisant la technologie ONT® sur des cultures présentant différents ratios hôte/Aph (1 et 10 %) et utilisant « l’adaptive sampling » pour enrichir en temps réel la fraction d’ADN bactérien ont permis d’atteindre des profondeurs de 7X et 65X. Des optimisations restent nécessaires pour améliorer l’enrichissement et le multiplexage des échantillons. Notre preuve de concept démontre la faisabilité du séquençage ONT® d’Aph à partir d’échantillons faiblement enrichis et ouvre la voie au séquençage de génomes plus diversifiés qui permettront d’approfondir les connaissances épidémiologiques sur Aph.
ano.nymous@ccsd.cnrs.fr.invalid (Clotilde Rouxel) 09 Mar 2026
https://hal.science/hal-05543411v1
