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[hal-04994083] Risk factors for tick infestation and equine Piroplasmosis infection among draught horses in France
Equine piroplasmosis, caused by the protozoan parasites Babesia caballi and Theileria equi, is endemic in Europe's Mediterranean basin, creating significant health and economic challenges for the equine sector. With no available vaccine, an eco-epidemiological approach is essential in order to identify and implement effective preventive measures. With this aim in view, we identified risk factors associated with B. caballi and T. equi infections and tick infestation for draught horses in the Auvergne-Rhône-Alpes region of France, known for its high piroplasmosis seroprevalence. During the spring of 2021, blood samples from 146 horses and ticks from both hosts and pastures were collected across 38 farms, then analysed using PCR to determine parasite prevalence. Environmental and meteorological data, along with information on management practices and individual horse characteristics, were collected on-site and from national databases. The results showed significant spatial variability in T. equi and B. caballi prevalence in horses, ranging from 25.7 % [95 % CI: 13.1 -43.6] to 83.7 % [95 % CI: 69.8 -92.2] and from 0 % [95 % CI: 0.0 -26.8] to 26.5 % [95 % CI: 15.4 -41.3], respectively. Among 1046 collected ticks, 3 % carried either a species of Babesia or Theileria and were identified as Dermacentor marginatus, Dermacentor reticulatus or Ixodes ricinus. We showed a stronger link between the environment and tick exposure for T. equi infections, while B. caballi infections were more closely associated with individual horse characteristics and management practices. Key risk factors for tick infestation included environmental conditions (temperature, rainfall, vegetation cover, altitude, etc.) and the presence of wild animals in pastures. These findings provide a valuable foundation on which to develop targeted prevention and control strategies to protect horses in enzootic regions.
ano.nymous@ccsd.cnrs.fr.invalid (Clémence Nadal) 17 Mar 2025
https://hal.science/hal-04994083v1
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[hal-04976824] Protocol to study the impact of breast cancer on colonization resistance of mouse microbiota using network node manipulation
<div><p>Network analysis is a powerful tool for investigating complex interactions between different microbial taxa within a community. We present a protocol to study the gut microbial community in a mouse model of breast cancer using a network-based approach. Here, we describe the procedures for tumor cell production and inoculation and 16S rRNA data processing. We then detail steps for constructing co-occurrence networks based on correlations between microbial abundances.</p></div>
ano.nymous@ccsd.cnrs.fr.invalid (Ana Laura Cano-Argüelles) 04 Mar 2025
https://hal.science/hal-04976824v1
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[hal-04998205] First identification of Cryptosporidium parvum virus 1 (CSpV1) in various subtypes of Cryptosporidium parvum from humans and diarrheic calves, lambs and goat kids in France
Cryptosporidium spp. remain a major cause of waterborne diarrhea and illness in developing countries and represent a significant burden to farmers worldwide. Cryptosporidium parvum virus 1 (CSpV1), of the genus Cryspovirus, was first reported to be present in the cytoplasm of C. parvum in 1997. Full-length genome sequences have been obtained from C. parvum from Iowa (Iowa), Kansas (KSU) and China. We aimed at characterizing the genome of CSpV1 from France and used sequence analysis from Cryptosporidium isolates to explore whether CSpV1 genome diversity varies over time, with geographical sampling location, with C. parvum genetic diversity, or with ruminant host species. A total of 123 fecal samples of cattle, sheep and goats were collected from 17 different French departments (57 diseased animal fecal samples and 66 healthy animal fecal samples). Subtyping analysis of the C. parvum isolates revealed the presence of two zoonotic subtypes families IIa and IId. Sequence analysis of CSpV1 revealed that all CSpV1 from France, regardless of the subtype of C. parvum (IIaA15G2R1, IIaA17G2R1 and IIdA18G1R1) are more closely related to CSpV1 from Turkey, and cluster on a distinct branch from CSpV1 collected from C. parvum subtype IIaA15G2R1 from Asia and North America. We also found that samples collected on a given year or successive years in given location are more likely to host the same subtype of C. parvum and the same CSpV1 strain. Yet, there is no distinct clustering of CSpV1 per French department or ruminants, probably due to trade, and transmission of C. parvum among host species. All together, these results provide insightful information regarding CSpV1 evolution and suggest the virus might be used as an epidemiological tracer for C. parvum. Future studies need to investigate CSpV1 role in C. parvum virulence and on subtype ability to infect different species.
ano.nymous@ccsd.cnrs.fr.invalid (Karim Adjou) 20 Mar 2025
https://hal.inrae.fr/hal-04998205v1
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[hal-04976808] A Warming World, a Growing Threat: The Spread of Ticks and Emerging Tick-Borne Diseases
Ticks are obligate hematophagous arachnids that play a critical role in transmitting a wide array of pathogens to humans, domestic animals, and wildlife [...]
ano.nymous@ccsd.cnrs.fr.invalid (Miray Tonk-Rügen) 04 Mar 2025
https://hal.science/hal-04976808v1
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[hal-04976807] Effects of Live and Peptide-Based Antimicrobiota Vaccines on Ixodes ricinus Fitness, Microbiota, and Acquisition of Tick-Borne Pathogens
This study explored the effects of antimicrobiota vaccines on the acquisition of Borrelia and Rickettsia, and on the microbiota composition of Ixodes ricinus ticks. Using a murine model, we investigated the immunological responses to live Staphylococcus epidermidis and multi-antigenic peptide (MAP) vaccines. Immunized mice were infected with either Borrelia afzelii or Rickettsia helvetica, and subsequently infested with pathogen-free I. ricinus nymphs. We monitored the tick feeding behavior, survival rates, and infection levels. Additionally, we employed comprehensive microbiota analyses, including the alpha and beta diversity assessments and microbial co-occurrence network construction. Our results indicate that both live S. epidermidis and MAP vaccines elicited significant antibody responses in mice, with notable bactericidal effects against S. epidermidis. The vaccination altered the feeding patterns and fitness of the ticks, with the Live vaccine group showing a higher weight and faster feeding time. Microbiota analysis revealed significant shifts in the beta diversity between vaccine groups, with distinct microbial networks and taxa abundances observed. Notably, the MAP vaccine group exhibited a more robust and complex network structure, while the Live vaccine group demonstrated resilience to microbial perturbations. However, the effects of antimicrobiota vaccination on Borrelia acquisition appeared taxon-dependent, as inferred from our results and previous findings on microbiota-driven pathogen refractoriness. Staphylococcus-based vaccines altered the microbiota composition but had no effect on B. afzelii infection, and yielded inconclusive results for R. helvetica. In contrast, previous studies suggest that E. coli-based microbiota modulation can induce a pathogen-refractory state, highlighting the importance of both bacterial species and peptide selection in shaping microbiota-driven pathogen susceptibility. However, a direct comparison under identical experimental conditions across multiple taxa is required to confirm this taxon-specific effect. These findings suggest that antimicrobiota vaccination influences tick fitness and microbiota assembly, but its effects on pathogen transmission depend on the bacterial taxon targeted and the selected peptide epitopes. This research provides insights into the need for strategic bacterial taxon selection to enhance vaccine efficacy in controlling tick-borne diseases.
ano.nymous@ccsd.cnrs.fr.invalid (Apolline Maitre) 04 Mar 2025
https://hal.science/hal-04976807v1
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[hal-04976812] New insights into the antifungal and anti-mycotoxigenic potential of the TickCore3 peptide against Fusarium species causing Fusarium head blight
Cereal crops are frequently affected by Fusarium species that are responsible for the devastating fungal disease Fusarium head blight (FHB). These Fusarium species are also capable of producing mycotoxins that accumulate in grains. Reducing the use of synthetic fungicides in agriculture while guaranteeing low levels of mycotoxin contamination in crops requires the development of innovative and environment-friendly solutions. TickCore3 (TC3) is the γ-core of the Ixodes ricinus tick defensin DefMT3. This peptide was previously reported as a potent antifungal and anti-mycotoxin agent, but was only tested against one strain of Fusarium graminearum, which is only one of the species causing FHB. In this study, we demonstrated that the peptide was active against major Fusarium species infecting wheat and could mitigate the accumulation of various mycotoxins. Fungal susceptibility to TC3 was shown to vary significantly according to the species and the strain as well. We found that TC3 is highly efficient when applied to the spores and has a strong anti-germination activity. Using a FITC-labeled TC3 peptide and confocal microscopy, we showed that TC3 has a strong affinity for the conidia surface and surrounds these fungal structures. Finally, the implementation of in planta tests demonstrated the bioactivity of TC3 when applied on wheat leaves. This study provides additional convincing results supporting the huge potential of TC3 as a novel and efficient antifungal agent to control FHB.</p></div>
ano.nymous@ccsd.cnrs.fr.invalid (Valentin Leannec-Rialland) 13 Mar 2025
https://hal.science/hal-04976812v1
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[hal-04976810] Microbial community variations in adult Hyalomma dromedarii ticks from single locations in Saudi Arabia and Tunisia
Introduction The camel-infesting tick, Hyalomma dromedarii , is a prominent ectoparasite in the Middle East and North Africa (MENA) region, critically impacting camel health and acting as a vector for tick-borne pathogens. Despite prior studies on its microbiota, the effects of geographic origin and sex on microbial community structure and functional stability remain poorly understood. Methods To address this, we characterized the bacterial microbiota of H. dromedarii ticks collected from camels in Tunisia (TUN) and Saudi Arabia (SA) using 16S rRNA gene sequencing, microbial network analysis, and metabolic pathway prediction. Results Our findings indicate a dominant presence of Francisella endosymbionts in Tunisian ticks, suggesting adaptive roles of H. dromedarii ticks in arid ecosystems. Keystone taxa, particularly Staphylococcus and Corynebacterium , were identified as central to microbial network structure and resilience. Moreover, network robustness analyses demonstrated enhanced ecological stability in the Tunisian tick microbiota under perturbation, indicative of higher resilience to environmental fluctuations compared to Saudi Arabian ticks. Additionally, functional pathway predictions further revealed geographically distinct metabolic profiles between both groups (Tunisia vs. Saudi Arabia and males vs. females), underscoring environmental and biological influences on H. dromedarii microbiota assembly. Discussion These results highlight region-specific and sex-specific microbial adaptations in H. dromedarii , with potential implications for pathogen transmission dynamics and vector resilience. Understanding these microbial interactions may contribute to improved strategies for tick control and tick-borne disease prevention.
ano.nymous@ccsd.cnrs.fr.invalid (Myriam Kratou) 04 Mar 2025
https://hal.science/hal-04976810v1
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[hal-04976809] Unseen Dangers—The Role of Invasive Species in the Spread of Zoonotic Diseases in Europe
In a recent study, Klink et al [...]
ano.nymous@ccsd.cnrs.fr.invalid (Myriam Kratou) 04 Mar 2025
https://hal.science/hal-04976809v1
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[hal-04976818] Two Human Infections with Diverse Europe-1 Crimean-Congo Hemorrhagic Fever Virus Strains, North Macedonia, 2024
<div><p>C rimean-Congo hemorrhagic fever (CCHF) is a se- vere zoonotic disease endemic in various regions of Europe, Asia, and Africa, including the Balkans, central Asia, and sub-Saharan Africa (1). The disease is caused by the CCHF virus (CCHFV), which is predominantly maintained and transmitted by Hyalomma spp. ticks. However, the virus also can be transmitted to humans through direct contact with the bodily fluids of infected animals and humans (2). In 2023, CCHF reemerged in North Macedonia (3; D. Jakimovski et al., unpub. data, https://doi.org/10.21203/rs.3.rs-4360716/v1), having been absent for &gt;50 years since a 1970 outbreak. The combined mortality rate for the 1970 and 2023 outbreaks was 18.75% (3/16 cases) (4; D. Jakimovski et al., unpub. data). In response to this escalating public health concern in the Balkan Region (D. Jakimovski et al., unpub. data), the Balkan Association for Vector-Borne Diseases implemented a strategic plan emphasizing clinical vigilance and capacity sharing. Those efforts culminated in the detection and characterization of an autochthonous CCHFV strain linked to the 2023 outbreak (D. Jakimovski et al., unpub. data). Our study explored the reemergence of CCHF cases in North Macedonia, emphasizing the co-circulation of multiple autochthonous viral strains.</p></div> <div>The Study<p>On April 26, 2024, a man in his 60s (case-patient 1) with no notable medical history was admitted to the Clinic for Infectious Diseases in Skopje (CIDS), Skopje, North Macedonia. He resided alone in a rural village in the northeastern region of North Macedonia in the municipality of Kriva Palanka (Figure 1). He worked as a self-employed herder and had not traveled outside the region in the preceding month. On April 14, 2024, the patient noticed a tick attached on his left lower leg and removed it with tweezers. The exposure site was ≈17 km south of the border with Serbia and ≈15 km east of the border with Bulgaria (Figure 1). Seven days after tick removal (day 0), the patient had malaise and persistent nosebleeds, which continued despite nasal tamponade. On day 4, he noticed dark stools, prompting a visit to an internal medicine specialist. Laboratory tests revealed leucopenia, thrombocytopenia, and elevated aminotransferase levels (Appendix 1,</p></div>
ano.nymous@ccsd.cnrs.fr.invalid (Dejan Jakimovski) 04 Mar 2025
https://hal.science/hal-04976818v1
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[hal-04937147] Changement climatique pour les nuls : Impact pour le vivant
Thématique de la session « Changement climatique », on en entend parler tous les jours dans les médias. Mais en pratique qu’en est-il ? Cette session animée par des conférenciers de renom va nous permettre de mieux appréhender les bases de ce changement et son impact sur le vivant. Changement global du climat, à quoi s’attendre ? par ANNESI-MAESANO Isabella, Montpellier Comment modéliser le changement climatique ? par ROBIN Dominique, Marseille Impact pour le vivant par HADDAD Nadia, Maisons-Alfort
ano.nymous@ccsd.cnrs.fr.invalid (Nadia Haddad) 09 Feb 2025
https://hal.science/hal-04937147v1
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[hal-04976815] Genetic and Immunological Insights into Tick-Bite Hypersensitivity and Alpha-Gal Syndrome: A Case Study Approach
Tick-bite hypersensitivity encompasses a range of clinical manifestations, from localized allergic reactions to systemic conditions like alpha-gal syndrome (AGS), an IgE-mediated allergy to galactose-α-1,3-galactose (α-Gal). This study investigated the clinical, molecular, immunological, and genetic features of two hypersensitivity cases. Two cases were analyzed: a 30-year-old woman with fixed drug reaction (FDR)-like hypersensitivity and a 10-year-old girl with AGS exhibiting borderline α-Gal-specific IgE. Diagnostic methods included allergen-specific IgE quantification, HLA genotyping, histopathological examination, and the molecular detection of tick-borne pathogens using microfluidic PCR. Case I demonstrated histopathological features of chronic lymphocytic inflammation and eosinophilic infiltrates, with HLA-B13 and DRB113 alleles indicating genetic susceptibility to hypersensitivity, while histological findings suggested a localized FDR-like reaction. Case II exhibited borderline α-Gal-specific IgE, resolving completely with a mammalian-free diet. The presence of HLA-DRB101 and DQB1*05 in the second patient indicated a genetic predisposition to AGS and other atopic conditions. No infectious etiology was identified in either case. These findings emphasize the heterogeneity of tick-related hypersensitivity and the importance of HLA genotypes in susceptibility. Comprehensive molecular, immunological, and genetic profiling offers valuable insights into the mechanisms of hypersensitivity, supporting personalized approaches for the diagnosis and management of tick-induced allergic conditions.
ano.nymous@ccsd.cnrs.fr.invalid (Pavle Banović) 04 Mar 2025
https://hal.science/hal-04976815v1
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[hal-04976821] <i>Neoehrlichia mikurensis</i>: an emerging pathogen in Southeastern Poland – prevalence in <i>Ixodes ricinus</i> ticks and phylogenetic characterization
<div>Introduction and<p>Objective. Neoehrlichia mikurensis is an emerging pathogen increasingly detected in ticks, animals, and humans. The study aimed to investigate the presence and phylogenetic diversity of Ixodes ricinus ticks in the Subcarpathian Region. Materials and Method. Of the 412 ticks collected from forest and meadow habitats, 240 specimens underwent molecular analysis for presence of N. mikurensis using microfluidic real-time PCR. Selected amplicons were sequenced to preform phylogenetic analysis of the groEL gene. Results. N. mikurensis infection was confirmed in 6.35% of female and 2.38% of male ticks, with no significant differences in the prevalence between habitats. Phylogenetic analysis revealed a low genetic diversity N. mikurensis. Conclusions. The findings confirm the infection of I. ricinus ticks with N. mikurensis in the studied region. The studied N. mikurensis groEL gene sequences showed low genetic variation, identical to other populations in Poland and Europe.</p></div>
ano.nymous@ccsd.cnrs.fr.invalid (Zbigniew Zając) 04 Mar 2025
https://hal.science/hal-04976821v1
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[hal-04873329] Borrelia, Leishmania, and Babesia: An Emerging Triad of Vector-Borne Co-Infections?
Canine leishmaniosis (CanL), caused by the protozoan Leishmania infantum and transmitted primarily by phlebotomine sand flies, poses significant challenges for zoonotic disease management [...]
ano.nymous@ccsd.cnrs.fr.invalid (Elianne Piloto-Sardiñas) 08 Jan 2025
https://hal.science/hal-04873329v1
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[hal-04707197] Genome sequences of four Ixodes species expands understanding of tick evolution
Background: Ticks, hematophagous Acari, pose a significant threat by transmitting various pathogens to their vertebrate hosts during feeding. Despite advances in tick genomics, high-quality genomes were lacking until recently, particularly in the genus Ixodes, which includes the main vectors of Lyme disease. Results: Here, we present the genome sequences of four tick species, derived from a single female individual, with a particular focus on the European species Ixodes ricinus, achieving a chromosome-level assembly. Additionally, draft assemblies were generated for the three other Ixodes species, I. persulcatus, I. pacificus, and I. hexagonus. The quality of the four genomes and extensive annotation of several important gene families have allowed us to study the evolution of gene repertoires at the level of the genus Ixodes and of the tick group. We have determined gene families that have undergone major amplifications during the evolution of ticks, while an expression atlas obtained for I. ricinus reveals striking patterns of specialization both between and within gene families. Notably, several gene family amplifications are associated with a proliferation of single-exon genes—most strikingly for fatty acid elongases and sulfotransferases. Conclusions: The integration of our data with existing genomes establishes a solid framework for the study of gene evolution, improving our understanding of tick biology. In addition, our work lays the foundations for applied research and innovative control targeting these organisms.
ano.nymous@ccsd.cnrs.fr.invalid (Alexandra Cerqueira de Araujo) 24 Sep 2024
https://hal.inrae.fr/hal-04707197v1
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[hal-04873345] Microbiome of Hyalomma dromedarii (Ixodida: Ixodidae) Ticks: Variation in Community Structure with Regard to Sex and Host Habitat
Hyalomma dromedarii ticks are the main hematophagous ectoparasites of camels, harboring a variety of microbes that can affect tick vector competence and pathogen transmission. To better understand the tick microbiome influenced by sex and host habitat, we analyzed the bacterial community of H. dromedarii male and female ticks collected from camel farms, livestock markets, and slaughterhouses, representing the range of major habitats in the UAE, by sequencing the 16S rRNA gene. Tick samples were collected during 2022 and 2023. A total of 40 ticks (male (15), female (15), and nymph (10)) were selected from tick samples collected from camels and processed for genomic DNA and next-generation sequencing using the Illumina MiSeq platform. We obtained 151,168 read counts, and these formed 237 operational taxonomic units representing 11 phyla, 22 classes, 77 families, and 164 genera. The phyla Actinomycetota, Bacillota, Bacteroidota, Pseudomonadota, and Fusobacteriota were the most abundant. The bacterial genus Corynebacterium dominated the microbiomes of farm-collected female H. dromedarii ticks, while Proteus dominated the microbiomes of farm-collected male H. dromedarii ticks. In comparison, the microbiomes of H. dromedarii ticks collected from slaughterhouse samples were dominated by genus Francisella in both males and females. Our results confirm that the bacterial microbiomes of H. dromedarii ticks vary by sex and habitat settings. Furthermore, recent findings could deliver insight into the differences in the ability of camel ticks to acquire, maintain, and transmit pathogens in various habitats that may impact the tick vector competence of medically and agriculturally important species in the Middle East and North Africa (MENA) region and Asia.
ano.nymous@ccsd.cnrs.fr.invalid (Nighat Perveen) 08 Jan 2025
https://hal.science/hal-04873345v1
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[hal-04882240] Transcriptomic plasticity in hybrid schistosomes can contribute to their zoonotic potential
Hybrids between Schistosoma haematobium and S. bovis are linked to both human and animal infections, highlighting the complex interspecies interactions that contribute to the spread of schistosomiasis. Additionally, S. bovis can infect multiple ruminant hosts, facilitating cross- species transmission and increasing the risk of zoonotic outbreaks. In this study, we investigated transcriptomic plasticity as a potential mechanism enabling hybrid schistosomes to adapt to alternative definitive hosts. We focused on two contexts: 1) introgressed S. haematobium × S. bovis hybrids, which demonstrated higher virulence in sheep compared to parental S. bovis, and 2) S. bovis infecting different host species. Our analysis uncovered 366 differentially expressed genes (DEGs), representing 4% of the total protein-coding genes, between introgressed hybrids and parental S. bovis in sheep. We also identified transcriptomic changes in S. bovis across different mammalian hosts (hamster and sheep), with around 30% of the total genes differentially expressed, demonstrating that S. bovis parasites display a high transcriptomic plasticity, allowing them to infect different definitive hosts. Shared enriched biological processes during introgression and host change include nuclear-transcribed mRNA catabolic processes, inner mitochondrial membrane organization, microtubule-based movement, response to endoplasmic reticulum stress, and sensory perception. These findings suggest that transcriptomic plasticity in S. bovis and hybrid worms enhance their ability to adapt and infect diverse host species, potentially increasing their zoonotic potential. This raises concerns for schistosomiasis epidemiology, as this plasticity could expand the parasite’s transmission capacity and complicate control efforts.
ano.nymous@ccsd.cnrs.fr.invalid (Nelia Luviano Aparicio) 13 Jan 2025
https://hal.science/hal-04882240v1
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[hal-04873356] The Mosquito Microbiota: A Key Player in Vector Competence and Disease Dynamics
Mosquitoes are well-known vectors for a range of pathogens, including Plasmodium parasites, which cause malaria in reptiles, birds, and mammals [...]
ano.nymous@ccsd.cnrs.fr.invalid (Vaidas Palinauskas) 08 Jan 2025
https://hal.science/hal-04873356v1
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[hal-04867693] New insights regarding tick co-infection. (Invited speaker).
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Sara Moutailler) 06 Jan 2025
https://hal.inrae.fr/hal-04867693v1
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[hal-04828846] Guild Dynamics and Pathogen Interactions in Hyalomma Ticks From Algerian Cattle
Ticks are pivotal in transmitting a variety of pathogens that affect both humans and animals. These pathogens often occur in guilds, groups of species that exploit similar resources in similar ways. Although the composition of tick‐borne pathogen (TBP) guilds is well‐documented, the interactions among pathogens within these guilds remain poorly understood. We hypothesized that abiotic and biotic factors significantly influence the patterns of occurrence and interactions among pathogens within these guilds. To investigate this, we analyzed microfluidic‐based high‐throughput data on microorganisms from 166 Hyalomma excavatum ticks (94 male and 72 female) collected across different seasons from cattle in the central Algerian steppe using network analysis to uncover complex pathogen–pathogen interaction patterns. We found that female ticks had a higher infection rate (63.9%) with common pathogens such as Rickettsia slovaca (26.4%), unclassified Apicomplexa (22.2%), and Borrelia afzelii (19.4%). Male ticks showed a 56.4% infection rate, with Rickettsia (31.1%) and R. slovaca (16%) being the most prevalent. Notable pathogen–pathogen interactions within guilds were identified, with positive associations such as between R. slovaca and Rickettsia conorii in males, and B. afzelii and Borrelia spielmanii in females, indicating cooperative interactions. Conversely, negative associations, such as between Anaplasma phagocytophilum and Francisella tularensis , suggested competitive exclusion. The observed variation in interaction patterns under different conditions indicates that ecological determinants, both biotic and abiotic, influence pathogen association dynamics within guilds. These findings have significant implications for understanding disease transmission and developing control strategies.
ano.nymous@ccsd.cnrs.fr.invalid (Salma Kaoutar Abdelali) 10 Dec 2024
https://hal.inrae.fr/hal-04828846v1
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[hal-04846136] The network MASCARA : Identification of local vector species involved in the transmission of arboviruses
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Barbara Viginier) 18 Dec 2024
https://hal.science/hal-04846136v1
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[hal-04828854] Wide spectrum of tick-borne pathogens in juvenile Ixodes ricinus collected from autumn-migrating birds in the Vistula River Valley, Poland
Background: Migratory birds serve as potential hosts for ticks and can be reservoirs of tick-borne pathogens (TBPs). The aim of our study was to investigate the prevalence of TBPs in juvenile Ixodes ricinus collected from Erithacus rubecula, Turdus merula, and Turdus philomelos passing through the Vistula River Valley, Poland — one of the most important European north-south routes for migratory birds. Methods: To detect TBPs in collected ticks we used a high-throughput microfluidic real-time PCR method. In addition, we performed a phylogenetic analysis of Borreliella garinii flaB and Rickettsia helvetica ompB sequences, considering haplotype diversity through a Median Joining Network. Results: Our results showed a high prevalence and wide spectrum of TBPs in both larvae and nymphs of I. ricinus. Overall, including co-infections, 47.41% of the tested tick specimens were infected with at least one TBP. Borreliaceae spirochetes were detected in ticks collected from all examined bird species. Ticks (larvae and nymphs) collected from T. merula showed the highest prevalence of Bo. garinii (33.33%), Bo. burgdorferi s.s. (7.69%) and Borrelia miyamotoi (2.56%), while the highest number of ticks infected with Bo. valaisiana were collected from T. philomelos (8.11%). In turn, the highest prevalence of R. helvetica (20.00%) was observed in ticks collected from E. rubecula. Additionally, infections with A. phagocytophilum (5.00%), Ehrlichia spp. (2.50%), Ba. divergens (2.50%) and Ba. venatorum (2.50%) were only confirmed in ticks collected from this bird species. The phylogenetic analysis of Bo. garinii revealed that the detected haplotype circulates widely across various hosts and is geographically widespread, while the haplotype of R. helvetica is mainly detected in ticks in Central Europe. Conclusions: Ticks carried by T. merula, T. philomelos, and E. rubecula migrating along the Vistula River Valley, Poland are characterized by a high prevalence and a wide spectrum of detected TBPs. Tested ticks carry widespread strains of Bo. garinii, in contrast to R. helvetica, which is mainly found in Central Europe. Therefore, further research on the possible role of birds as reservoirs of TBPs is needed.
ano.nymous@ccsd.cnrs.fr.invalid (Joanna Kulisz) 10 Dec 2024
https://hal.inrae.fr/hal-04828854v1
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[hal-04867705] New insights regarding tick co-infection. (invited speaker)
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Sara Moutailler) 06 Jan 2025
https://hal.inrae.fr/hal-04867705v1
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[hal-04867712] High-throughput nanotechnologies for tick-borne pathogens detection. (Invited speaker).
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Sara Moutailler) 06 Jan 2025
https://hal.inrae.fr/hal-04867712v1
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[anses-04372908] Exploring the relationship between Faecalibacterium duncaniae and Escherichia coli in inflammatory bowel disease (IBD): Insights and implications
Inflammatory bowel disease (IBD) is a group of disorders characterized by an inflammation of the gastrointestinal tract (GIT) and represents a major social and economic burden. Despite ongoing research into the etiology and pathophysiology of this multifactorial disease, treatment options remain limited. From this perspective, the gut microbiota has emerged as a potential player in the pathogenesis of IBD, and animal and human studies support this hypothesis. Indeed, the human gut is one of the most complex ecological communities (composed of 1013-1014 microorganisms) that plays a critical role in human health by influencing normal physiology and disease susceptibility through its collective metabolic activities and host interactions. In addition, live probiotic bacteria present in some food products (which transit through the GIT) have been shown to interact with the host immune system and confer several health benefits. The aim of this review is to provide an overview of the link between Faecalibacterium duncaniae and Escherichia coli and IBD, highlighting the main areas of research in this field. An ecological perspective on the gut microbiota may offer new insights for the development of clinical therapies targeting this bacterial community to improve human health.
ano.nymous@ccsd.cnrs.fr.invalid (Alejandro Cabezas-Cruz) 08 Feb 2024
https://anses.hal.science/anses-04372908v1
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[hal-04693283] Broad range molecular detection methods identify only Borrelia spp. in erythema migrans biopsies and blood of tick-bitten patients
In this multicenter study conducted in France, we challenged the hypothesis of the transmission of pathogens other than Borrelia spp. in 22 patients developing erythema migrans following a tick bite. Using a combination of high-throughput microfluidic PCRs and agnostic metagenomics on skin biopsies and blood samples, no microorganisms other than Borrelia spp. was found.
ano.nymous@ccsd.cnrs.fr.invalid (Philippe Pérot) 12 Sep 2024
https://hal.inrae.fr/hal-04693283v1
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[hal-04873378] Recognizing a Silent Threat: Canine Ehrlichiosis and Rickettsiosis in Northern Portugal
Vector-borne diseases pose significant challenges for both animal and public health worldwide [...]
ano.nymous@ccsd.cnrs.fr.invalid (Zbigniew Zając) 08 Jan 2025
https://hal.science/hal-04873378v1
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[hal-04846088] Le Réseau MASCARA en Auvergne-Rhône-Alpes : identification d’espèces vectrices locales impliquées dans la transmission d’arbovirus.
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Viginier Barbara) 18 Dec 2024
https://hal.science/hal-04846088v1
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[hal-04820540] Culot urinaire : c'est quoi ce cristal ?
L’analyse physico-chimique des urines ne donne aucune information sur la présence de cristaux dans les urines et ne suffit pas à l’interprétation correcte des résultats obtenus grâce à la bandelette urinaire. L’examen du culot urinaire permet une évaluation semi-quantitative des éléments en suspension dans les urines en revanche, en l’absence de coloration, les détails cellulaires sont peu visibles.
ano.nymous@ccsd.cnrs.fr.invalid (Pierre Lucien Deshuillers) 05 Dec 2024
https://hal.science/hal-04820540v1
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[hal-04820554] Jaune... rouge, verte, noire : que dit la couleur de l'urine ?
L’urine est normalement jaune clair, jaune ou légèrement ambrée, transparente à légèrement trouble. Ces couleurs et turbidités sont le résultat du volume d’urine et de sa concentration et donc de l’état d’hydratation du patient, ainsi que de la quantité de pigments qu’elle contient : urochrome et urobiline. Une couleur anormale peut provenir d’un changement d’état de santé, du régime alimentaire, de l’administration de médicaments ou de l’environnement aboutissant à un changement de composition des pigments d’origine endogène ou pigments exogènes. Dans tous les cas, lors d’une analyse d’urine, la couleur des urines doit être examinée et reportée parce qu’elle peut donner des indications sur les processus physiopathologiques en cours. Il est aussi important de noter ces changements de couleur car ils peuvent gêner l’interprétation des plages réactives colorées de la bandelette urinaire.
ano.nymous@ccsd.cnrs.fr.invalid (Pierre Lucien Deshuillers) 05 Dec 2024
https://hal.science/hal-04820554v1
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[hal-04820568] Bien regarder les comptes rendus de cytologie : erreurs fréquentes d'interprétation
Le rapport de cytologie est le medium de communication entre le pathologiste et le clinicien dont la finalité est d’aboutir au diagnostic ou diagnostic différentiel pour un patient. Son importance est majeure puisque les informations qu’il contient vont dicter la prise en charge clinique du patient par le clinicien. Cependant, la communication d’informations peut être source de confusion, parfois au détriment du patient. Il est donc essentiel de s’assurer de la meilleure transmission de ces informations entre le clinicien et le pathologiste, pour que conjointement ils arrivent aussi loin que possible dans l’établissement d’un diagnostic pour le patient.
ano.nymous@ccsd.cnrs.fr.invalid (Pierre Lucien Deshuillers) 05 Dec 2024
https://hal.science/hal-04820568v1
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[hal-04825248] Investigating contamination of ready-to-eat salads with Toxoplasma gondii oocysts in a European-wide multicenter survey
The majority of horizontal Toxoplasma gondii infections in humans are assumed to be foodborne. The relative contribution of the meat-borne (tissue cysts) versus environmental (oocyst-driven) routes of infections is largely unknown. The consumption of unwashed raw fruits or vegetables contaminated with T. gondii oocysts has been identified as a putative risk factor. Important methodological inconsistencies and limitations have been identified in the surveys carried out worldwide in fresh produce. The present study aimed to unravel the occurrence of T. gondii oocysts in commercially available ready-to-eat (RTE) salad mixes in ten European countries. For that purpose, the detection methodology was first validated in an interlaboratory ring trial. Next, a harmonized sampling strategy and the validated methodology were implemented by all participants. In this multicentre study, weekly sampling (from October 2021 to October 2022) was set to detect seasonal variations. Two categories of RTE salad mixes (baby leaves and cut leaves mixes) were sampled to explore potential associations between oocyst contamination and cultivation and growth conditions. In the study period, 3,329 RTE salad samples were tested using a standard operating procedure (SOP) that allows molecular detection of T. gondii oocysts in such matrices with a detection limit of 10 oocysts per 30 g of salad. Robustness and sensitivity of this SOP as well as the comparability of results among the laboratories had been confirmed in the ring trial before the start of the study. The key analytical steps include oocysts recovery by sample washing followed by pelleting of the eluate by centrifugation, DNA extraction and DNA detection by triplex qPCR, targeting two multicopy fragments (529RE, B1 gene) and an internal amplification control. Positive samples were confirmed by ITS-1 single tube nested PCR followed by Sanger sequencing. This is the first European-wide study to estimate the prevalence of T. gondii oocysts in RTE leafy green salads using a validated and standardized procedure to assess the associated potential risk for human infections. This work was done as part of TOXOSOURCES project, EU Horizon 2020 Research and Innovation programme under grant agreement No 773830: One Health European Joint Programme.
ano.nymous@ccsd.cnrs.fr.invalid (Nadja S. Bier) 07 Dec 2024
https://hal.science/hal-04825248v1
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[hal-04796956] Vaccination et santé publique, le cas du mpox.
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ano.nymous@ccsd.cnrs.fr.invalid (Nadia Haddad) 21 Nov 2024
https://hal.science/hal-04796956v1
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[hal-04802710] Tick-Borne Encephalitis Virus Infection in a Two-Year-Old Child Returning from Switzerland (July–August 2023): Is It Time for TBE Immunization of Serbian Travelers?
Tick-borne encephalitis (TBE) is a vaccine-preventable viral infection that poses significant public health challenges, particularly in regions where tick-borne diseases are endemic. This case report describes a 2-year-old boy with confirmed abortive TBEV infection following a tick bite during travel to Switzerland. The patient developed fever and mild symptoms but did not exhibit central nervous system involvement. The case underscores the importance of raising awareness among healthcare providers and travelers from non-endemic areas, such as Serbia, about TBE risk and the potential benefits of preventive vaccination. Strategic immunization campaigns could mitigate the public health impact of travel-related TBE.
ano.nymous@ccsd.cnrs.fr.invalid (Verica Simin) 25 Nov 2024
https://hal.science/hal-04802710v1
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[hal-04791479] Diversity and Distribution of Bacterial and Parasitic Tick-Borne Pathogens in Armenia, Transcaucasia
Background: Variations in the distribution and prevalence of pathogens in ticks can have significant consequences for human health. Information on these variables in Transcaucasia is scarce, so the aim of our study was to conduct a large-scale study to detect selected tick-borne infectious agents in Armenia. Methods: Overall, 209 adult ticks were collected from different hosts including 4 samples from human clothes. We tested ticks using high-throughput microfluidic single-cell real-time PCR to detect 42 genospecies of pathogens. We used GIS to determine biotic and abiotic factors governing the prevalence of pathogens and applied statistical analyses to test the association between prevalence of pathogens depending on hosts, locality and environment. Results: From 209 samples, 134 were positive to targeted pathogens. Anaplasma phagocytophilum Foggie, 1949 was the most prevalent case (44%). The highest overall prevalence was observed in ticks from sheep (74%), followed by cows (67%) and calves (60%). The highest multiple infection rates were also detected in sheep (40%) and calves (40%) followed by cows (28%). One statistically significant association was found among co-infections (P&lt;0.05). The prevalence of pathogens varied according to locality. The abundance of Anaplasma spp. is significantly correlated with “slope” and “vegetation” factors. Similar patterns were detected for other pathogens. Conclusion: This was the first large-scale survey of multiple tick-borne pathogens in Armenia and Transcaucasia. The results of this study shed light on spatial variations in pathogen infection rate among adult ticks found on hosts and underline a number of environmental determinants of pathogen distribution among ticks.
ano.nymous@ccsd.cnrs.fr.invalid (Sargis Aghayan) 19 Nov 2024
https://hal.science/hal-04791479v1
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[hal-04807620] Stomoxys calcitrans : un potentiel vecteur mécanique d’Anaplasma phagocytophilum ?
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ano.nymous@ccsd.cnrs.fr.invalid (Clotilde Rouxel) 27 Nov 2024
https://hal.science/hal-04807620v1
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[hal-04808997] Taxonomie intégrative des tiques d’Afrique tropicale : actualisation des connaissances et anticipation de potentielles émergences de maladies à tiques en Europe.
Les maladies émergentes sont en recrudescence en lien avec les changements globaux observés actuellement et près d’un quart sont des maladies vectorielles. Le transport passif via les oiseaux migrateurs d’Afrique vers l’Europe semble être aussi une voie majeure d’introduction de tiques et donc potentiellement d’agents pathogènes et de nouvelles maladies vectorielles. Ainsi, sur l’île de Malte, a été recensé récemment l’import par un passereau migrateur d’une espèce d’Ixodes, du sous-genre Afrixodes, en provenance d’Afrique tropicale. 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 9 espèces d’Afrixodes disposent d’au moins une séquence déposée dans Genbank. Basée sur une large collection de tiques (681 spécimens) prélevées sur des micromammifères (rongeurs et musaraignes) d’Afrique tropicale, le travail de taxonomie intégrative proposé dans le cadre de cette thèse vise notamment à développer de nouveaux outils d’identifications moléculaires et morphologiques. Une méthode d’extraction d’ADN non-destructive, adaptée ici pour les tiques, donne accès à des données moléculaires sur les tiques et les microorganismes qu’elles hébergent (endosymbiotes, pathogènes…) tout en conservant leur intégrité corporelle, permettant ainsi des investigations relevant de la morphométrie géométrique. Cette approche intégrative permet ainsi de caractériser ces espèces et de réviser leur systématique tout en recherchant des agents pathogènes qu’elles pourraient héberger.
ano.nymous@ccsd.cnrs.fr.invalid (Camille Lorang) 28 Nov 2024
https://hal.science/hal-04808997v1
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[hal-04855042] Evaluation du niveau d'infestation des poulains par Parascaris spp. en Normandie
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ano.nymous@ccsd.cnrs.fr.invalid (Kenza Bourrier) 24 Dec 2024
https://hal.science/hal-04855042v1
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[hal-04779454] Just Hitching a Ride: Stable Isotopes Reveal Non‐Feeding Behaviour of Anisakis simplex Within Its Host Fish
Anisakis simplex larvae, commonly found in marine fish, cause anisakiasis in humans, resulting in gastric to gastro‐allergic symptoms. Despite known health risks, the impact of Anisakidae larvae on fish hosts is less understood. This study aimed to investigate this interaction by assessing the feeding strategy of A. simplex . Anisakis larvae were isolated from North Sea Merluccius merluccius tissues (stomach, body cavity, liver and muscle) and were analysed for carbon (δ 13 C) and nitrogen (δ 15 N) isotope values. Significant differences in δ 13 C values were found among host tissues, with the liver differing from muscle and stomach tissues. In contrast, no differences were noted for the associated parasites. Additionally, δ 15 N values indicated that the host occupied a significantly higher relative trophic position than its parasite. This suggests a lack of direct nutrient transfer from host to parasite, as the parasite would typically exhibit higher stable isotope values than the tissue they feed on. Therefore, A. simplex 's stable isotope values might reflect those of its previous host (crustacean and/or small fish), providing insights into diet and movement of the paratenic M. merluccius host. Further research is needed to confirm these findings across different fish species and to explore A. simplex as a proxy for trophic ecology.
ano.nymous@ccsd.cnrs.fr.invalid (Amandine Sabadel) 13 Nov 2024
https://hal.science/hal-04779454v1
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[hal-04805880] Two types of axonal muscarinic acetylcholine receptors mediate formation of saliva cocktail in the tick Ixodes ricinus
The secretion of salivary gland (SG) in ticks is effectively triggered by the muscarinic acetylcholine receptor (mAChR) agonist, the pilocarpine, known as a worldwide-preferred tool for obtaining copious saliva. Presently, all we know is, that injection or apical application of pilocarpine, into/on partially-fed tick females induces robust long-lasting salivary secretion, whereas it fails to induce salivation from isolated SG. Cutting neuronal connections between tick synganglion and SG, support the involvement of a neural mAChR in these processes. Based on these observations, it has been generally believed that tick synganglion neurons, mediates SG fluid secretion via unidentified non-cholinergic “secreto-motor nerves”, connecting neuronal cells with SG. Currently, the only known processes, associating specific tick neurons with SG are the neuropeptidergic axons innervating either type II or both type II/III saliva-producing acini. Here, based on agonistic/antagonistic assessments along mutant-based verifications, we revealed that Ixodes ricinus tick, possesses two pharmacologically distinct types (-A and -B) of mAChR. The synganglion was suggested to sense cholinomimetics via rich axonal arborizations at its surface, originating from two clusters of peptidergic neurosecretory cells, each expressing either mAChR-A or -B. Furthermore, both sets of neuropeptidergic SG-innervating cells also possess a cholinoceptive feature by expressing either of these two receptor types on their terminals in saliva producing type II and III acini. Following this model, the effects of in vivo-injected selective muscarinic agents, put forward that co-joint action of two different axonal mAChRs mediate a tandem cooperation of type II/III SG acini for saliva cocktail formation.
ano.nymous@ccsd.cnrs.fr.invalid (Ladislav Šimo) 26 Nov 2024
https://hal.inrae.fr/hal-04805880v1
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[hal-04826836] Professional carrer and lessons to learn
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ano.nymous@ccsd.cnrs.fr.invalid (Radu Blaga) 09 Dec 2024
https://hal.science/hal-04826836v1
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[hal-04803061] First evidence of circulation of multiple arboviruses in Algeria
Background Algeria like other North African countries is experiencing recurrent episodes of West Nile Virus (WNV) emergences and new health threats associated with the introduction of Aedes albopictus in 2010 are to be feared. To improve the surveillance of mosquito-borne pathogens, we performed a study using innovative tools based on multiplex molecular methods. Methods We combined two approaches: a high-throughput chip based on the BioMark Dynamic array system to detect arboviruses in mosquitoes, and a set of immunologic methods (ELISA, microsphere immunoassays (MIA) and virus microneutralization tests (MNT)) for serological surveys in animal hosts. We investigated two distinct regions: a first zone located in the coastal humid region and a second one in the Saharan desert region. Principal findings We collected a total of 1,658 mosquitoes belonging to nine different species and found predominantly Culex pipienss . l . (56.5%) and Cx . perexiguus (27.5%). From 180 pools of 10 mosquitoes, we detected four arboviruses: Banna virus (BAV), chikungunya virus (CHIKV), Sindbis virus (SINV), and Usutu virus (USUV). Moreover, we examined 389 blood samples from equids and poultry and found that 52.4% were positive for flavivirus antibodies in ELISA, while 30.8% were positive for WNV and two chickens and two equids were positive for USUV by MNT and MIA respectively. Conclusions To our knowledge, this is the first report of five arboviruses circulating in Algeria, with three reported for the first time (CHIKV, BAV, and USUV). Our study brings evidence that reinforcing surveillance using more discriminant tools may help in anticipating future emergences and propose adapted control measures.
ano.nymous@ccsd.cnrs.fr.invalid (Saïd Boubidi) 29 Nov 2024
https://hal.inrae.fr/hal-04803061v1
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[anses-04859478] Demande d’avis relatif à l’évaluation des risques pour la santé publique et la santé animale liés à la transmission inter-espèces (être humain-animal et animal-être humain) des virus influenza en élevage porcin et les mesures de surveillance et de prévention à mettre en œuvre
À la date de rédaction de ce rapport, quatre genres d’influenzavirus sont distingués au sein de la famille des Orthomyxoviridae : le genre Alphainfluenzavirus (virus influenza de type A ou IAV), le genre Betainfluenzavirus (virus influenza de type B ou IBV), le genre Gammainfluenzavirus (virus influenza de type C ou ICV) et le genre Deltainfluenzavirus (IDV). Les IAV sont les virus influenza qui ont la plus grande diversité d’espèces hôtes (oiseaux et mammifères) et sont les seuls à avoir été responsables de pandémies de grippe. Le porc héberge des IAV, lesquels sont responsables de l’influenza porcin. Le porc peut être infecté par des ICV, mais, comme chez l’être humain, ceux-ci ne provoquent pas d’infections symptomatiques. Il peut également être infecté par des IDV (transmis par les bovins), qui pourraient jouer un rôle dans le complexe respiratoire porcin mais dont la circulation au sein de l’espèce porcine n’est pas démontrée. Ainsi, les risques (pour la santé publique et la santé animale) liés à la transmission inter-espèces des virus influenza en élevage porcin concernent très majoritairement les IAV. La présente évaluation a donc uniquement porté sur les IAV. D’après le texte de la saisine, « les IAV ont une propension importante à évoluer, notamment par mutations ou par réassortiments génomiques. Ces virus sont isolés chez de nombreuses espèces animales, sauvages comme domestiques, ainsi que chez l’être humain. Certaines souches sont hautement pathogènes pour leurs hôtes et/ou sont capables de passer la barrière d’espèces. Ces virus peuvent ainsi avoir un impact sanitaire et économique majeur tant en santé publique humaine que vétérinaire. Ils peuvent en effet être zoonotiques et présenter un potentiel pandémique et panzootique comme en témoignent les épidémies et épizooties des dernières décennies. L’influenza porcin ou la grippe du porc, causée par un IAV, est une maladie respiratoire virale fréquente dans les élevages de porcs français, et tous les virus influenza porcins sont à potentiel zoonotique. Le porc peut être infecté par des IAV porcins mais également par des IAV humains ou aviaires. Il peut donc devenir un hôte intermédiaire pour la transmission de virus influenza aviaires à l’être humain, mais aussi servir de « mixing vessel », où, à la faveur des co-infections, de nouveaux virus réassortants peuvent émerger. Les souches circulant chez le porc en France font l’objet d’une surveillance événementielle par le Réseau national de surveillance des virus influenza porcins (Résavip). Le Laboratoire National de Référence pour l’influenza porcin (LNR-IP) (Anses, Laboratoire de Ploufragan-Plouzané-Niort) mène également des activités de recherche sur ces virus. Les lieux de détention (élevages, abattoirs, etc.) de suidés et de volailles sont des lieux de circulation de virus animaux dans des conditions de grande proximité avec l’être humain. Des cas de transmission de virus influenza d’origine porcine à l’être humain ont été mis en évidence à plusieurs reprises à l’étranger et récemment en France. Un risque de réassortiment, chez l’animal ou l’être humain co-infecté par des virus d’origine animale et/ou humaine existe et est possiblement accentué lors de la saison de circulation des virus grippaux humains ». Au regard du risque pour la santé publique que représentent les virus influenza porcins, la DGAL a sollicité l’expertise de l’Anses le 8 septembre 2021 (demande d’appui scientifique et technique - AST du 8 septembre 2021) pour qu’une investigation épidémiologique soit conduite dans un élevage porcin présumé être à l’origine d’un cas humain d’infection par un virus influenza porcin survenu en août 2021, en lien avec les travaux d’investigation épidémiologique chez l’être humain qui ont été coordonnés par Santé Publique France (SPF) et conduits par l’Agence Régionale de Santé (ARS) Bretagne. La Haute Autorité de Santé (HAS) et le Haut Conseil de Santé Publique (HCSP) avaient été saisis concomitamment en septembre 2021 concernant les questions de la vaccination contre la grippe saisonnière des personnes exposées aux virus influenza porcins et des mesures de protection des intervenants dans les lieux de détention des porcins.
ano.nymous@ccsd.cnrs.fr.invalid (Catherine Belloc) 30 Dec 2024
https://anses.hal.science/anses-04859478v1
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[hal-04693288] Contributions of birds to the feeding of ticks at host community level: Effects of tick burden, host density and yearly fluctuations
The eco-epidemiology of tick-borne diseases hinges on the abundance and distribution of hosts that sustain tick populations and the pathogens they carry. Research into the role of bird species in the feeding of Ixodes ricinus ticks, the primary tick species of veterinary and public health importance in Europe, remains scarce. This study endeavors to bridge these knowledge gaps by (i) assessing the density of feeding ticks (DFT) within a bird community to pinpoint species making substantial contributions, and (ii) exploring interannual variations in DFT over an extended timeline. Furthermore, we investigate whether variations in individual tick burden (TB) were more closely associated with the characteristics of bird species or interannual variations affecting the density of questing tick, using interannual TB variation as a surrogate. To fulfill these aims, we conducted a 13-year longitudinal study monitoring I. ricinus ticks feeding on a bird community in a periurban forest in France, covering breeding periods from 2007 to 2019. Within this community, we identified seven principal bird species significantly contributing to I. ricinus tick feeding: the Common Blackbird (Turdus merula), the Song Thrush (Turdus philomelos), the European Robin (Erithacus rubecula), the Dunnock (Prunella modularis), the Eurasian Blackcap (Sylvia atricapilla), the Great Tit (Parus major), and the Common Nightingale (Luscinia megarhynchos). Our results show that the bird community’s contribution to tick feeding remained relatively consistent from year-to-year, though certain years displayed higher or lower DFT values related to the average over the study period. Moreover, five out the seven major species accounted for 80 % to 95 % of DFT annually. Consequently, we emphasized the need to broaden the scope of future research on bird contributions to tick population dynamics beyond merely thrushes (Turdidae species), to encompass a more diverse range of species, particularly those common birds that engage in ground foraging activities. Furthermore, variations in individual tick burden were predominantly influenced by the characteristics of bird species rather than by interannual variability in infestation rates. This finding suggests a significant role for species-specific traits in determining tick exposure and susceptibility. In conclusion, our study offers new insights into the medium-term dynamics of tick-bird ecological systems, underscoring the need for future study of tick populations and their interactions with vertebrate hosts to improve our understanding of tick-borne disease circulation.
ano.nymous@ccsd.cnrs.fr.invalid (Amalia Rataud) 10 Sep 2024
https://hal.inrae.fr/hal-04693288v1
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[hal-04880752] Crossed effects of helminth infection and lead exposure on fitness: An experimental study in feral pigeons ( Columba livia )
Abstract Living organisms are exposed to multiple environmental factors that can affect their fitness. The negative effects of these simultaneous stressors can be additive or can interact in negative synergistic or antagonistic ways to affect the health of exposed individuals. Parasites can accumulate pollutants in their own tissues and have been shown to increase the tolerance of their hosts to different pollutants (antagonistic interaction between parasites and pollutants). Through an experimental approach, we tested the existence of combined antagonistic effects between intestinal parasites and lead exposure on urban feral pigeons ( Columba livia ) which are known to be exposed to trace metal pollution and harbour a wide variety of internal and external parasites. We experimentally exposed wild feral pigeons in captivity to two treatments: an anthelmintic treatment to eliminate intestinal nematode parasites; an exposure to lead for a period of 6 months. We tested the effects of these crossed treatments on several components of fitness: immunocompetence, reproduction, and body mass. Our findings suggest that the overall effects of lead exposure, either alone or in combination with the presence of intestinal parasites (without anthelmintic treatment) were negative, through either additive or synergistic means. Our results reveal the existence of negative combined effects between pollutant exposure and intestinal parasites, highlighting the importance of accounting for multiple stress factors when studying the effects of exposure to pollutants and/or other environmental stressors on the fitness of organisms.
ano.nymous@ccsd.cnrs.fr.invalid (Aurélie Jeantet) 11 Jan 2025
https://hal.science/hal-04880752v1
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[hal-04764916] Nested patterns of commensals and endosymbionts in microbial communities of mosquito vectors
Abstract Background Mosquitoes serve as vectors for numerous pathogens, posing significant health risks to humans and animals. Understanding the complex interactions within mosquito microbiota is crucial for deciphering vector-pathogen dynamics and developing effective disease management strategies. Here, we investigated the nested patterns of Wolbachia endosymbionts and Escherichia-Shigella within the microbiota of laboratory-reared Culex pipiens f. molestus and Culex quinquefasciatus mosquitoes. We hypothesized that Wolbachia would exhibit a structured pattern reflective of its co-evolved relationship with both mosquito species, while Escherichia-Shigella would display a more dynamic pattern influenced by environmental factors. Results Our analysis revealed different microbial compositions between the two mosquito species, although some microorganisms were common to both. Network analysis revealed distinct community structures and interaction patterns for these bacteria in the microbiota of each mosquito species. Escherichia-Shigella appeared prominently within major network modules in both mosquito species, particularly in module P4 of Cx. pipiens f. molestus , interacting with 93 nodes, and in module Q3 of Cx. quinquefasciatus , interacting with 161 nodes, sharing 55 nodes across both species. On the other hand, Wolbachia appeared in disparate modules: module P3 in Cx. pipiens f. molestus and a distinct module with a single additional taxon in Cx. quinquefasciatus , showing species-specific interactions and no shared taxa. Through computer simulations, we evaluated how the removal of Wolbachia or Escherichia-Shigella affects network robustness. In Cx. pipiens f. molestus , removal of Wolbachia led to a decrease in network connectivity, while Escherichia-Shigella removal had a minimal impact. Conversely, in Cx. quinquefasciatus , removal of Escherichia-Shigella resulted in decreased network stability, whereas Wolbachia removal had minimal effect. Conclusions Contrary to our hypothesis, the findings indicate that Wolbachia displays a more dynamic pattern of associations within the microbiota of Culex pipiens f. molestus and Culex quinquefasciatus mosquitoes, than Escherichia - Shigella . The differential effects on network robustness upon Wolbachia or Escherichia-Shigella removal suggest that these bacteria play distinct roles in maintaining community stability within the microbiota of the two mosquito species.
ano.nymous@ccsd.cnrs.fr.invalid (Justė Aželytė) 04 Nov 2024
https://hal.science/hal-04764916v1
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[hal-04764999] New TBV monitoring tools.
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ano.nymous@ccsd.cnrs.fr.invalid (Sara Moutailler) 04 Nov 2024
https://hal.inrae.fr/hal-04764999v1
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[hal-04752519] Culicoides biting midges among cattle in France: be wary of data in the literature
Culicoides are vectors that can transmit many different pathogens to mammals — including humans, and domestic and wild animals — and birds. In order to take preventive measures against any vector-borne disease, it is important to gather information on both the host and vector species. Culicoides species are mainly mammalophilic, ornithophilic or ornithophilic/mammalophilic, but females have also been found to occasionally feed on engorged insects. A recent systematic review based on three groups of key words investigated Culicoides on farms, and asserted that 92 species (including four not present species) have been reported among cattle in mainland France and Corsica. We have re-evaluated the presence of Culicoides species in cattle in France using the same data of the review. Our data show that only 18 species are reported among cattle. Furthermore, our research used molecular and indirect investigations to analyse Culicoides species that had been feeding on cattle. Our results demonstrate that 45 species feed on cattle out of 92 species present in France. The paper discusses the relevance of data in the literature when investigating hosts of Culicoides species.
ano.nymous@ccsd.cnrs.fr.invalid (Christine Millot) 24 Oct 2024
https://hal.science/hal-04752519v1
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[hal-04803235] Integrated protein-protein interaction and RNA interference screens reveal novel restriction and dependency factors for tick-borne encephalitis virus in its human host
In Europe, tick-borne encephalitis virus (TBEV) causes severe neurological disease in humans. As an obligate intracellular organism, TBEV relies on manipulating host metabolic processes and evading antiviral defenses for its survival. This is accomplished largely through binary interactions between specific viral proteins and host proteins. These protein-protein interactions (PPIs) constitute molecular determinants of critical pathobiologic traits of viruses, including host range, zoonotic potential and virulence, and making them realistic targets for antiviral therapies. To better understand the pathobiology of TBEV in humans, we mapped the network of PPIs between TBEV and its human host using interaction proteomics. We performed a high-throughput screen for virus-host PPIs by means of yeast two-hybrid methodology, utilizing the complete set of TBEV open reading frames and Homo sapiens cDNA libraries. This screen revealed a large number of human proteins that directly interact with TBEV viral proteins, many of which had not previously been associated with viral infections. We further investigated the functional significance of these host interactors in viral infection as viral dependency or restriction factors using RNA interference and bioinformatics analysis, identifying approximately 40% of the human proteins as having a significant impact on TBEV replication. These proteins are involved in diverse biological processes, some of which are expected to play a role in viral infection. Ongoing research is now focused on understanding the mechanisms of action of some of the most influential factors in the TBEV viral cycle. More broadly, this work aims to illuminate how tick-borne flaviviruses manipulate cellular processes to cause disease and to identify viral vulnerabilities that could be targeted therapeutically.
ano.nymous@ccsd.cnrs.fr.invalid (Marion Marion Sourisseau) 25 Nov 2024
https://hal.inrae.fr/hal-04803235v1
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[hal-04765006] Integrative approaches to Managing Tick-borne Diseases : Modelling coinfections and Harnessing Vector Microbiome Vaccines.
[...]
ano.nymous@ccsd.cnrs.fr.invalid (Sara Moutailler) 04 Nov 2024
https://hal.inrae.fr/hal-04765006v1
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[hal-05007508] First detection of Crimean–Congo haemorrhagic fever virus in Hyalomma marginatum ticks, southern France
Ticks, which are vectors of several zoonotic pathogens, represent an important and increasing threat for human and veterinary health. Hyalomma marginatum, one of the main tick vectors of the Crimean-Congo Haemorrhagic Fever (CCHF) virus, has been present in Corsica for decades. Given the recent establishment of this tick species in continental France, it was crucial to evaluate the epidemiological situation of CCHFV in France. Transmission of the CCHFV to humans occurs predominantly via bites of Hyalomma ticks, especially H. marginatum and H. lusitanicum in Europe, or via exposure to infected blood or tissues from viraemic animals or humans. As ticks are the only known natural reservoirs of CCHFV, we focused on field collection of ticks. We collected ticks from horses, which are considered to be the preferred hosts of H. marginatum and on cattle, which are considered as good amplifiers of CCHFV and thus enhance local virus circulation. We collected ticks in the Pyrénées-Orientales department where antibodies against CCHFV were identified in 2021-2022 from cattle. Cattle farms with the highest within-herd seroprevalences were selected, as well as a few seronegative farms in the same areas. In addition, farms with horses, located in the neighbourhood of the seropositive cattle farms were also visited. The ticks H. marginatum, analyzed molecularly, revealed the presence of CCHFV in this department, in proportions ranging from 3.1% to 55.8% of infected ticks across positive sites. All CCHFV isolates sequenced in this study were highly identical and belonged to the same genotype (genotype III). This finding confirms for the first time the transmission of CCHFV in France and highlights the need for close monitoring of H. marginatum in areas where the tick is already established, and further investigations into its probability of geographic expansion.
ano.nymous@ccsd.cnrs.fr.invalid (Célia Bernard) 26 Mar 2025
https://hal.science/hal-05007508v1
