Molecular Biology and Parasitic Immunology


JRU "Molecular Biology and Parasite Immunology"

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



19 March 2024

Redaction: Sophie Bertrand - Clotilde Rouxel

Lisa Le Dortz thesis defence

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

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HAL : Dernières publications

  • [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. (Alejandro Cabezas-Cruz) 08 Feb 2024
  • [hal-04530626] Enrichment and characterization of muscle extracellular vesicles (EVs) during Trichinella spiralis infection in mice

    During the muscle invasion by Trichinella spiralis newborn larvae (NBL), the transformation of muscle cells to nurse cells is still not understood, in particular the molecular interplays between host and parasite remains not identified. The emerging role of extracellular vesicles (EVs) in the latest decades opens a new field in the understanding of how the pathogen makes itself a niche indispensable for its survival. Produced by almost all cell types, it has been identified as a new way of cell-cell communication in mammals and a new way of host-pathogen interactions in helminths. Muscle cells themselves produce EVs during physiological mechanisms, like regeneration (to which infection with Trichinella has been compared), or pathological conditions, like denervation, inflammation or insulin resistance. In regeneration, muscle cells exchange EVs with satellite cells to induce their proliferation or with immune cells to induce an inflammatory response. Moreover, muscle EVs are enriched in vimentin, an intermediate filament protein. We have previously shown that a NBL stage specific protein (NBL-1) induce the expression of vimentin in muscle cells in vitro. We therefore investigated muscle EVs in OF1 mice during oral infection by Trichinella spiralis (ISS004). EVs were enriched by ultracentrifugation after muscle digestion and analysed for their size and number by tunable resistive pulse sensing (tRPS), purity through the absence of cell-associated proteins (immunodetection in Western Blot), EVs-associated markers (CD9, CD63, Tsg101) and the vimentin protein content. The presence of Trichinella antigens has also been tested. Muscle EVs properties vary during the infection cycle. Vimentin and CD9 protein content of EVs (normalised to EVs protein rate) varies. CD9 tetraspanin is also known as a regulator of cell fusion during muscle regeneration. These results will allow to initiate a more global analysis of local EVs in muscle by proteomic and transcriptomic to understand how the parasite and the cell populations interact through this way. New biomarker or vaccine target candidates may thus be identified. (Marie Maurer) 03 Apr 2024
  • [anses-04509655] Avis de l'Anses relatif à la fièvre hémorragique de Crimée-Congo

    Selon la saisine, la fièvre hémorragique de Crimée-Congo (FHCC) est une maladie vectorisée par les tiques, potentiellement grave chez l’être humain, présente en Europe de l’Est et, depuis une dizaine d’années, en Espagne. Les espèces vectrices du genre Hyalomma sont présentes en Corse et sur le littoral méditerranéen. La transmission par les fluides biologiques est également mentionnée. Dans le cadre de son mandat auprès de la DGAL pour surveiller les maladies animales ou les zoonoses exotiques émergentes en France, le Centre de coopération internationale en recherche agronomique (CIRAD) a prélevé, sur des bovins d’élevage des Pyrénées-Orientales, des tiques du genre Hyalomma chez lesquelles a été mis en évidence, en octobre 2023, le génome du virus de la FHCC. Les prévalences d’infection de ces tiques sont telles qu’elles suggèrent bien une circulation locale du virus de la FHCC. De surcroît, ces prévalences sont en complète cohérence avec les enquêtes sérologiques menées depuis 2018 dans la même zone, en particulier sur des bovins. Dans ce contexte, l’avis de l’Anses est sollicité pour : • proposer « des recommandations de prévention à destination des éleveurs de ruminants, intervenants en élevage et vétérinaires, des personnels des abattoirs et des chasseurs, ainsi que des agents du ministère de l’agriculture et de la souveraineté alimentaire en charge de l’inspection des abattoirs, au regard du risque d’infection par les fluides d’animaux virémiques. Ces recommandations porteront sur les mesures à appliquer selon les activités, les espèces animales concernées, les périodes à risque et les secteurs géographiques concernés. » Il est demandé de proposer « en particulier des mesures de réduction du risque lié aux fluides biologiques des animaux virémiques tout au long du processus d’élevage et en abattoir ». Il est également demandé de se prononcer « sur l’efficacité des options envisagées au regard du risque et leurs effets collatéraux ». • établir « une synthèse des zones et des périodes à risque au regard des différentes voies de transmission virale à l’humain, en s’appuyant notamment sur des données de surveillance acarologique, de sérologie et virologie animale et, le cas échéant, de sérologie humaine autour des élevages séropositifs ». [Saisine liée n°2020-SA-0039] (Nadia Haddad) 18 Mar 2024
  • [anses-04504013] Exploring type I interferon pathway: virulent vs. attenuated strain of African swine fever virus revealing a novel function carried by MGF505-4R

    African swine fever virus represents a significant reemerging threat to livestock populations, as its incidence and geographic distribution have surged over the past decade in Europe, Asia, and Caribbean, resulting in substantial socio-economic burdens and adverse effects on animal health and welfare. In a previous report, we described the protective properties of our newly thermo-attenuated strain (ASFV-989) in pigs against an experimental infection of its parental Georgia 2007/1 virulent strain. In this new study, our objective was to characterize the molecular mechanisms underlying the attenuation of ASFV-989. We first compared the activation of type I interferon pathway in response to ASFV-989 and Georgia 2007/1 infections, employing both in vivo and in vitro models. Expression of IFN-α was significantly increased in porcine alveolar macrophages infected with ASFV-989 while pigs infected with Georgia 2007/1 showed higher IFN-α than those infected by ASFV-989. We also used a medium-throughput transcriptomic approach to study the expression of viral genes by both strains, and identified several patterns of gene expression. Subsequently, we investigated whether proteins encoded by the eight genes deleted in ASFV-989 contribute to the modulation of the type I interferon signaling pathway. Using different strategies, we showed that MGF505-4R interfered with the induction of IFN-α/β pathway, likely through interaction with TRAF3. Altogether, our data reveal key differences between ASFV-989 and Georgia 2007/1 in their ability to control IFN-α/β signaling and provide molecular mechanisms underlying the role of MGF505-4R as a virulence factor. (Juliette Dupré) 14 Mar 2024
  • [hal-04500027] Age- and Sex-Associated Pathogenesis of Cell Culture-Passaged Kemerovo Virus in IFNAR(−/−) Mice

    Kemerovo virus (KEMV) is a tick-borne orbivirus transmitted by ticks of the genus Ixodes. Previous animal experimentation studies with orbiviruses, in particular the interferon receptor double knock-out (IFNAR(−/−)) mouse model, did not indicate bias that is related to age or sex. We endeavoured to assess the effect of serial and alternated passages of KEMV in mammalian or Ixodes cells on virus replication and potential virulence in male or female IFNAR(−/−) mice, with important age differences: younger males (4–5 months old), older males (14–15 months old), and old females (14–15 months old). After 30 serial passages in mammalian or tick cells, or alternated passages in the two cell types, older female mice which were inoculated with the resulting virus strains were the first to show clinical signs and die. Younger males behaved differently from older males whether they were inoculated with the parental strain of KEMV or with any of the cell culture-passaged strains. The groups of male and female mice inoculated with the mammalian cell culture-adapted KEMV showed the lowest viraemia. While older female and younger male mice died by day 6 post-inoculation, surprisingly, the older males survived until the end of the experiment, which lasted 10 days. RNA extracted from blood and organs of the various mice was tested by probe-based KEMV real-time RT-PCR. Ct values of the RNA extracts were comparable between older females and younger males, while the values for older males were >5 Ct units higher for the various organs, indicating lower levels of replication. It is noteworthy that the hearts of the old males were the only organs that were negative for KEMV RNA. These results suggest, for the first time, an intriguing age- and sex-related bias for an orbivirus in this animal model. Changes in the amino acid sequence of the RNA-dependent RNA polymerase of Kemerovo virus, derived from the first serial passage in Ixodes cells (KEMV Ps.IRE1), were identified in the vicinity of the active polymerase site. This finding suggests that selection of a subpopulation of KEMV with better replication fitness in tick cells occurred. (Camille Victoire Migné) 04 Apr 2024
  • [anses-04504002] First use of tissue exudate serology to identify Toxocara spp. infection in food animals

    Toxocara canis and Toxocara cati are globally distributed, zoonotic roundworm parasites. Human infection can have serious clinical consequences including blindness and brain disorders. In addition to ingesting environmental eggs, humans can become infected by eating infective larvae in raw or undercooked meat products. To date, no studies have assessed the prevalence of Toxocara spp. larvae in meat from animals consumed as food in the UK or assessed tissue exudates for the presence of anti-Toxocara antibodies. This study aimed to assess the potential risk to consumers eating meat products from animals infected with Toxocara spp. Tissue samples (226) were obtained from 155 different food producing animals in the south, southwest and east of England, UK. Tissue samples (n=226), either muscle or liver, were processed by artificial digestion followed by microscopic sediment evaluation for Toxocara spp. larvae, and tissue exudate samples (n=141) were tested for the presence of anti-Toxocara antibodies using a commercial ELISA kit. A logistic regression model was used to compare anti-Toxocara antibody prevalence by host species, tissue type and source. While no larvae were found by microscopic examination after tissue digestion, the overall prevalence of anti-Toxocara antibodies in tissue exudates was 27.7%. By species, 35.3% of cattle (n=34), 15.0% of sheep (n=60), 54.6% of goats (n=11) and 61.1% of pigs (n=18) had anti-Toxocara antibodies. Logistic regression analysis found pigs were more likely to be positive for anti-Toxocara antibodies (odds ration (OR) = 2.89, P=0.0786) compared with the other species sampled but only at a 10% significance level. The high prevalence of anti-Toxocara antibodies in tissue exudates suggests that exposure of food animals to this parasite is common in England. Tissue exudate serology on meat products within the human food chain could be applied in support of food safety and to identify practices that increase risks of foodborne transmission of zoonotic toxocariasis. (Sara Healy) 14 Mar 2024
  • [hal-04479142] La glutathionylation de la protéine mitochondriale humaine MIA40 régule l’homéostasie des ROS

    Dans le cadre du module d’enseignement « Physiopathologie de la signalisation » proposé par l’université Paris-Saclay, les étudiants du Master « Biologie Santé » se sont confrontés à l’écriture scientifique. Ils ont sélectionné des articles scientifiques dans le domaine de la signalisation cellulaire présentant des résultats originaux, via des approches expérimentales variées, sur des thèmes allant de l’exploration des sites de contacts membranaires aux mécanismes moléculaires de la ferroptose, en passant par la signalisation hépatique et tumorale. Après un travail préparatoire réalisé avec l’équipe pédagogique, les étudiants, organisés en binômes/trinômes, ont ensuite rédigé, guidés par des chercheurs, une Nouvelle soulignant les résultats majeurs et l’originalité de l’article étudié. Ils ont beaucoup apprécié cette initiation à l’écriture d’articles scientifiques et, comme vous pourrez le lire, se sont investis dans ce travail avec enthousiasme ! (Razika Arab) 27 Feb 2024
  • [hal-04493615] Noninvasive detection of Zika virus in mosquito excreta sampled from wild mosquito populations in French Guiana

    Arboviruses can be difficult to detect in the field due to relatively low prevalence in mosquito populations. The discovery that infected mosquitoes can release viruses in both their saliva and excreta gave rise to low-cost methods for the detection of arboviruses during entomological surveillance. We implemented both saliva and excreta-based entomological surveillance during the emergence of Zika virus (ZIKV) in French Guiana in 2016 by trapping mosquitoes around households of symptomatic cases with confirmed ZIKV infection. ZIKV was detected in mosquito excreta and not in mosquito saliva in 1 trap collection out of 85 (1.2%). One female Ae. aegypti L. (Diptera: Culicidae) was found with a ZIKV systemic infection in the corresponding trap. The lag time between symptom onset in a ZIKV-infected individual living near the trap site and ZIKV detection in this mosquito was 1 wk. These results highlight the potential of detection in excreta from trapped mosquitoes as a sensitive and cost-effective method to non invasively detect arbovirus circulation. (Amandine Guidez) 08 Mar 2024
  • [anses-04467525] Four powdered plants for prevention of <i>Aeromonas hydrophila</i> disease in Nile tilapia (<i>Oreochromis niloticus</i>)

    As alternatives to antibiotics and growth promoters, herbs and medicinal plants can contribute to new strategies for aquatic health management, and have great potential for more sustainable aquaculture. Four plants, Pelargonium roseum, Schinus terenbinthifolius, Murraya koenigii and Aphloia theiformis, widely distributed in tropical countries were studied to assess their efficacy in the prevention and reduction of mortality caused by experimental infection with Aeromonas hydrophila on Nile tilapia, Oreochromis niloticus. Powdered plants were incorporated into fish feed, and fish were fed with an enriched diet for 40 days before a challenge with the pathogen. No negative impact on the condition factor, weight gain or specific growth rate was observed in fish fed with the plant supplements, and the best growth was observed in fish fed with P. roseum. Mortality was significantly reduced in fish treated with A. theiformis compared to other fish from plant species and control, with a relative survival rate (RPS) of up to 30%. (Domenico Caruso) 20 Feb 2024
  • [hal-04449145] Detection of Crimean–Congo haemorrhagic fever virus in Hyalomma marginatum ticks, southern France, May 2022 and April 2023

    Crimean–Congo haemorrhagic fever (CCHF), a potentially severe zoonotic viral disease causing fever and haemorrhagic manifestations in humans. As the Crimean–Congo haemorrhagic fever virus (CCHFV) has been detected in ticks in Spain and antibodies against the virus in ruminant sera in Corsica, it was necessary to know more about the situation in France. In 2022–2023, CCHFV was detected in 155 ticks collected from horses and cattle in southern France. (Célia Bernard) 27 Feb 2024
  • [hal-04512941] Pathogen community composition and co-infection patterns in a wild community of rodents

    Rodents are major reservoirs of pathogens that can cause disease in humans and livestock. It is therefore important to know what pathogens naturally circulate in rodent populations, and to understand the factors that may influence their distribution in the wild. Here, we describe the occurrence and distribution patterns of a range of endemic and zoonotic pathogens circulating among rodent communities in northern France. The community sample consisted of 713 ro- dents, including 11 host species from diverse habitats. Rodents were screened for virus expo- sure (hantaviruses, cowpox virus, Lymphocytic choriomeningitis virus, Tick-borne encephalitis virus) using antibody assays. Bacterial communities were characterized using 16S rRNA am- plicon sequencing of splenic samples. Multiple correspondence (MCA), multiple regression and association screening (SCN) analyses were used to determine the degree to which ex- trinsic factors (study year and site; host habitat, species, sex and age class) contributed to pathogen community structure, and to identify patterns of associations between pathogens within hosts. We found a rich diversity of bacterial genera, with 36 known or suspected to be pathogenic. We revealed that host species is the most important determinant of pathogen community composition, and that hosts that share habitats can have very different pathogen communities. Pathogen diversity and co-infection rates also vary among host species. Aggre- gation of pathogens responsible for zoonotic diseases suggests that some rodent species may be more important for transmission risk than others. Moreover, we detected positive asso- ciations between several pathogens, including Bartonella, Mycoplasma species, Cowpox virus (CPXV) and hantaviruses, and these patterns were generally specific to particular host species. Altogether, our results suggest that host and pathogen specificity is the most important driver of pathogen community structure, and that interspecific pathogen-pathogen associations also depend on host species. (Jessica L Abbate) 20 Mar 2024
  • [hal-04446370] Quels sont les facteurs associés aux niveaux de parasitisme interne chez les porcs dans les systèmes d'élevage alternatifs ?

    Une étude a été menée dans 112 élevages porcins alternatifs français (sur litière ou avec accès à l'extérieur) où des échantillons fécaux et sanguins ont été prélevés sur 10 truies, 10 porcs de 10-12 semaines d’âge et/ou 10 porcs en fin d'engraissement pour une analyse coprologique ainsi que pour des recherches d’anticorps dirigés contre Ascaris suum et Toxoplasma gondii. Des informations concernant la structure et la conduite de l’élevage ont été collectées lors de la visite de l'exploitation et ont fait l’objet d’analyses multidimensionnelles afin de déterminer des profils d’élevages au regard de l'infestation parasitaire et les caractéristiques de l'exploitation qui leur sont associés. Des oocystes de coccidies ont été observés dans les fèces de porcs dans la majorité des élevages (84 %), suivis par des œufs de strongles (55 %), Trichuris suis (32 %) et A. suum (16 %). Les taux d'élevages séropositifs pour A. suum et T. gondii étaient respectivement de 80 % et 56 %. L'hygiène et notamment la décontamination des installations sont des facteurs associés à un faible niveau de parasitisme. À l'inverse, l'élevage en plein air ou sur litière, un entretien médiocre des bâtiments, les élevages de petite taille ainsi que la saison (été) sont des paramètres associés à des niveaux élevés de parasitisme. L'utilisation de traitements anthelminthiques multiples sur les porcs en croissance était associée à une faible excrétion d’œufs de T. suis mais à des niveaux élevés de séroprévalence pour A. suum. Même si certains facteurs ne sont pas sous le contrôle des éleveurs (e.g. saison), des marges d'amélioration existent concernant l'hygiène et l'utilisation appropriée de traitements antiparasitaires. (Maxime Delsart) 08 Feb 2024
  • [hal-04493624] Tick-borne viruses and their risk to public health in the Caribbean: Spotlight on bats as reservoirs in Cuba

    In recent decades, tick-borne diseases (TBDs) have surged and expanded globally due to factors like changes in human activities, land use patterns, and climate change, and it have been associated with the emergence of zoonotic diseases. Cuba faces the impact of ticks on human health and the economy. Although Cuba has studied TBDs extensively for the past 50 years, focus on tick-borne viral pathogens affecting humans remains scant. Despite TBDs not currently being a major health concern in Cuba, factors like inadequate clinician awareness, climate conditions, global tick emergence, and evidence of zoonotic pathogens in ticks underscore the importance of enhanced TBD surveillance in the country. Here we revised the available information on ticks as vectors of pathogenic viruses to humans, spotlighting bats as potential reservoirs of tick-borne viruses (TBVs). Ticks on bats have gained interest as potential reservoirs of pathogenic viruses to humans in Cuba and worldwide. Understanding their role in maintaining viruses and their potential transmission to humans is crucial for the implementation of surveillance and control programs to reduce the risk of tick-borne viral diseases and public health management. (Maritza Pupo Antúnez) 07 Mar 2024
  • [hal-04434326] Aptamer selection against cell extracts containing the zoonotic obligate intracellular bacterium, Anaplasma phagocytophilum

    Abstract A. phagocytophilum is a zoonotic and tick-borne bacterium, threatening human and animal health. Many questions persist concerning the variability of strains and the mechanisms governing the interactions with its different hosts. These gaps can be explained by the difficulty to cultivate and study A. phagocytophilum because of its strict intracellular location and the lack of specific tools, in particular monoclonal antibodies, currently unavailable. The objective of our study was to develop DNA aptamers against A. phagocytophilum, or molecules expressed during the infection, as new study and/or capture tools. Selecting aptamers was a major challenge due to the strict intracellular location of the bacterium. To meet this challenge, we set up a customized selection protocol against an enriched suspension of A. phagocytophilum NY18 strain, cultivated in HL-60 cells. The implementation of SELEX allowed the selection of three aptamers, characterized by a high affinity for HL-60 cells infected with A. phagocytophilum NY18 strain. Interestingly, the targets of these three aptamers are most likely proteins expressed at different times of infection. The selected aptamers could contribute to increase our understanding of the interactions between A. phagocytophilum and its hosts, as well as permit the development of new diagnostic, therapeutic or drug delivery appliances. (Lisa Lucie Le Dortz) 08 Feb 2024
  • [hal-04442106] Exploring the Coinfection and Genetic Diversity of Multiple Tick-Borne Pathogens in Livestock Population of Punjab, Pakistan

    Tick-borne diseases affecting domestic animals and humans have increased globally in recent years. Pakistan, in particular, faces a significant economic threat from ticks, where two specific species, Rhipicephalus microplus and Hyalomma anatolicum, act as vectors for various pathogens such as piroplasma, Anaplasma, Ehrlichia, and Rickettsia that pose a significant burden on livestock production in the country. To better understand the risk that tick-borne pathogens (TBPs) pose to livestock in Pakistan, we conducted a cross-sectional study of the occurrence, diversity, and coinfection of these pathogens in small and large ruminants owned by small farms as well as in ticks collected from these animals. We collected blood samples from 224 cattle, 224 buffalo, 69 goats, and 56 sheep, gathered from 112 farms located in seven districts of Punjab, one of Pakistan’s largest province. In addition, we collected a total of 476 ticks attached to these animals. Based on the identification of tick species through morphology and sequence analysis of the 16S rRNA and cytochrome c oxidase subunit 1 (cox1) gene, we confirmed that the most commonly collected tick species were Rh. microplus (38.65% of all individuals), H. anatolicum (31.93%), and Rh. decoloratus (8.40%). Notable pathogens detected in the collected ticks included Theileria annulata (18.4% prevalence), Anaplasma ovis (15.79%), A. centrale (13.16%), and Rickettsia slovaca (13.16%). In blood samples, the most frequently detected pathogens were T. annulata (n = 8), Babesia bovis (n = 7), A. centrale (n = 6), and B. bigemina (n = 5). In some cases, both cattle and buffaloes were found to be coinfected with B. bovis, T. annulata, and A. centrale. These findings provide valuable insights into the circulation of TBPs in livestock and highlight the need for further research on the epidemiological risk that these pathogens pose to ruminants in Pakistan. (Sabir Hussain) 04 Apr 2024
  • [hal-04529152] Impact of Plasmodium relictum Infection on the Colonization Resistance of Bird Gut Microbiota: A Preliminary Study

    Avian malaria infection has been known to affect host microbiota, but the impact of Plasmodium infection on the colonization resistance in bird gut microbiota remains unexplored. This study investigated the dynamics of Plasmodium relictum infection in canaries, aiming to explore the hypothesis that microbiota modulation by P. relictum would reduce colonization resistance. Canaries were infected with P. relictum, while a control group was maintained. The results revealed the presence of P. relictum in the blood of all infected canaries. Analysis of the host microbiota showed no significant differences in alpha diversity metrics between infected and control groups. However, significant differences in beta diversity indicated alterations in the microbial taxa composition of infected birds. Differential abundance analysis identified specific taxa with varying prevalence between infected and control groups at different time points. Network analysis demonstrated a decrease in correlations and revealed that P. relictum infection compromised the bird microbiota’s ability to resist the removal of taxa but did not affect network robustness with the addition of new nodes. These findings suggest that P. relictum infection reduces gut microbiota stability and has an impact on colonization resistance. Understanding these interactions is crucial for developing strategies to enhance colonization resistance and maintain host health in the face of parasitic infections. (Justė Aželytė) 02 Apr 2024
  • [hal-04010177] Seasonality of host-seeking Ixodes ricinus nymph abundance in relation to climate

    Abstract There is growing concern about climate change and its impact on human health. Specifically, global warming could increase the probability of emerging infectious diseases, notably because of changes in the geographical and seasonal distributions of disease vectors such as mosquitoes and ticks. For example, the range of Ixodes ricinus, the most common and widespread tick species in Europe, is currently expanding northward and at higher altitudes. However, little is known about the seasonal variation in tick abundance in different climates. Seasonality of I. ricinus is often based on expert opinions while field surveys are usually limited in time. Our objective was to describe seasonal variations in I. ricinus abundance under different climates. To this end, a seven-year longitudinal study, with monthly collections of I. ricinus host-seeking nymphs, was carried out in France, in six locations corresponding to different climates. Tick data were log-transformed and grouped between years so as to obtain seasonal variations for a typical year. Daily average temperature was measured during the study period. Seasonal patterns of nymph abundance were established for the six different locations using linear harmonic regression. Model parameters were estimated separately for each location. Seasonal patterns appeared different depending on the climate considered. Western temperate sites showed an early spring peak, a summer minimum and a moderate autumn and winter abundance. More continental sites showed a later peak in spring, and a minimum in winter. The peak occurred in summer for the mountainous site, with an absence of ticks in winter. In all cases except the mountainous site, the timing of the spring peak could be related to the sum of degree days since the beginning of the year. Winter abundance was positively correlated to the corresponding temperature. Our results highlight clear patterns in the different sites corresponding to different climates, which allow further forecast of tick seasonality under changing climate conditions. (Thierry Hoch) 17 Jan 2024
  • [hal-04400072] Microfluidic PCR and network analysis reveals complex tick-borne pathogen interactions in the tropics

    Background Ixodid ticks, particularly Rhipicephalus sanguineus s.l., are important vectors of various disease-causing agents in dogs and humans in Cuba. However, our understading of interactions among tick-borne pathogens (TBPs) in infected dogs or the vector R. sanguineus s.l. remains limited. This study integrates microfluidic-based high-throughput real-time PCR data, Yule's Q statistic, and network analysis to elucidate pathogen-pathogen interactions in dogs and ticks in tropical western Cuba. Methods A cross-sectional study involving 46 client-owned dogs was conducted. Blood samples were collected from these dogs, and ticks infesting the same dogs were morphologically and molecularly identified. Nucleic acids were extracted from both canine blood and tick samples. Microfluidic-based high-throughput real-time PCR was employed to detect 25 bacterial species, 10 parasite species, 6 bacterial genera, and 4 parasite taxa, as well as to confirm the identity of the collected ticks. Validation was performed through end-point PCR assays and DNA sequencing analysis. Yule's Q statistic and network analysis were used to analyse the associations between different TBP species based on binary presence-absence data. Results The study revealed a high prevalence of TBPs in both dogs and R. sanguineus s.l., the only tick species found on the dogs. Hepatozoon canis and Ehrlichia canis were among the most common pathogens detected. Co-infections were observed, notably between E. canis and H. canis . Significant correlations were found between the presence of Anaplasma platys and H. canis in both dogs and ticks. A complex co-occurrence network among haemoparasite species was identified, highlighting potential facilitative and inhibitory roles. Notably, H. canis was found as a highly interconnected node, exhibiting significant positive associations with various taxa, including A. platys , and E. canis , suggesting facilitative interactions among these pathogens. Phylogenetic analysis showed genetic diversity in the detected TBPs. Conclusions Overall, this research enhances our understanding of TBPs in Cuba, providing insights into their prevalence, associations, and genetic diversity, with implications for disease surveillance and management. Graphical abstract (Cristian Díaz-Corona) 08 Feb 2024
  • [hal-04398431] Real-Time Microfluidic PCRs: A High-Throughput Method to Detect 48 or 96 Tick-borne Pathogens in 48 or 96 Samples

    Tick-borne pathogens (TBPs) are often detected through classical molecular tools (PCR, nested PCR, real-time PCR), but these are limited in terms of the number of targeted pathogens due to the volume of DNA available for analysis. To solve this problem, in 2014 we developed a new high-throughput method based on real-time microfluidic PCRs that can detect 48 or 96 pathogens in 48 or 96 samples in a single run, such as ten species from the Borrelia burgdorferi sensu lato group. We then used this technique for large-scale epidemiological studies of TBPs in tick and animal samples on an international scale through numerous collaborative projects. (Sara Moutailler) 16 Jan 2024
  • [hal-04275421] Aspergillosis in a colony of Humboldt penguins (Spheniscus humboldti) in a french zoological park: evaluation of environmental exposure

    Aspergillosis is a major health problem in captive penguins due to the inhalation and the development of airborne spores of opportunistic environmental molds of the genus Aspergillus. Diagnosis is often delayed and treatments, based on the use of azole antifungals, are not fully effective. This study assesses the risk of exposure to Aspergillus sp. and determines the environmental reservoirs in the direct environment of a colony of Humboldt penguins (Spheniscus humboldti) in a zoological park in Paris, and the risk of contamination with resistant isolates. Every 15 days between February and May 2022, environmental samples (air and subtract from the nests, pond water, pigeon and penguin droppings) were carried out in the penguin enclosure as well as clinical samples (one-time non-invasive sampling on chicks), and screened for Aspergillus sp. conidia. From 191 environmental samples, 264 strains of Aspergillus including 221 strains of A. fumigatus were isolated, mostly from ambient air, in the nests, and pond water. No &quot;at risk&quot; areas in the penguin environment have been highlighted, nor an increased risk because of the proximity with urban wild birds. However, the load of airborne Aspergillus in the nests increased significantly with outdoor temperature. Of the 221 strains isolated, we identified only one azole-resistant strain, displaying the TR34/L98H mutation in the cyp51A gene. This low prevalence of resistant strains may probably be partly explained by the urban location of the zoological park, surrounded by kilometers of urban areas without agricultural activities. (Tristan Bralet) 08 Nov 2023
  • [hal-04314233] High-throughput screening of pathogens in Ixodes ricinus removed from hosts in Lombardy, northern Italy

    Ticks are important vectors of many pathogens in Europe, where the most impactful species is Ixodes ricinus. Recently, the geographical distribution of this tick species has been expanding, resulting in an increased risk of human exposure to tick bites. With the present study, we aimed to screen 350 I. ricinus specimens collected from humans and wild animals (mainly ungulates), to have a broader understanding of the tick-borne pathogens circulating in the Lombardy region, in northern Italy. To do so, we took advantage of a high-throughput real-time microfluidic PCR approach to screen ticks in a cost-effective and time-saving manner. Molecular analysis of the dataset revealed the presence of four genera of bacteria and two genera of protozoa: in ungulates, 77 % of collected ticks carried Anaplasma phagocytophilum, while the most common pathogen species in ticks removed from humans were those belonging to Borrelia burgdorferi sensu lato group (7.6 %). We also detected other pathogenic microorganisms, such as Rickettisa monacensis, Rickettsia helvetica, Neoehrlichia mikurensis, Babesia venatorum, and Hepatozoon martis. Besides, we also reported the presence of the pathogenic agent Borrelia miyamotoi in the area (1.4 % overall). The most common dual co-infection detected in the same tick individual involved A. phagocytophilum and Rickettsia spp. Our study provided evidence of the circulation of different tick-borne pathogens in a densely populated region in Italy. (Sophie Melis) 09 Apr 2024
  • [hal-04522396] Genotyping of European Toxoplasma gondii strains by a new high-resolution next-generation sequencing-based method

    Abstract Purpose A new high-resolution next-generation sequencing (NGS)-based method was established to type closely related European type II Toxoplasma gondii strains. Methods T. gondii field isolates were collected from different parts of Europe and assessed by whole genome sequencing (WGS). In comparison to ME49 (a type II reference strain), highly polymorphic regions (HPRs) were identified, showing a considerable number of single nucleotide polymorphisms (SNPs). After confirmation by Sanger sequencing, 18 HPRs were used to design a primer panel for multiplex PCR to establish a multilocus Ion AmpliSeq typing method. Toxoplasma gondii isolates and T. gondii present in clinical samples were typed with the new method. The sensitivity of the method was tested with serially diluted reference DNA samples. Results Among type II specimens, the method could differentiate the same number of haplotypes as the reference standard, microsatellite (MS) typing. Passages of the same isolates and specimens originating from abortion outbreaks were identified as identical. In addition, seven different genotypes, two atypical and two recombinant specimens were clearly distinguished from each other by the method. Furthermore, almost all SNPs detected by the Ion AmpliSeq method corresponded to those expected based on WGS. By testing serially diluted DNA samples, the method exhibited a similar analytical sensitivity as MS typing. Conclusion The new method can distinguish different T. gondii genotypes and detect intra-genotype variability among European type II T. gondii strains. Furthermore, with WGS data additional target regions can be added to the method to potentially increase typing resolution. (M. Joeres) 05 Apr 2024
  • [hal-04505357] Immunosuppressive Ability of Trichinella spiralis Adults Can Ameliorate Type 2 Inflammation in a Murine Allergy Model

    Abstract Background There is an increase in the global incidence of allergies. The hygiene hypothesis and the old friend hypothesis reveal that helminths are associated with the prevalence of allergic diseases. The therapeutic potential of Trichinella spiralis is recognized; however, the stage at which it exerts its immunomodulatory effect is unclear. Methods We evaluated the differentiation of bone marrow–derived macrophages stimulated with T spiralis excretory-secretory products. Based on an ovalbumin-induced murine model, T spiralis was introduced during 3 allergy phases. Cytokine levels and immune cell subsets in the lung, spleen, and peritoneal cavity were assessed. Results We found that T spiralis infection reduced lung inflammation, increased anti-inflammatory cytokines, and decreased Th2 cytokines and alarms. Recruitment of eosinophils, CD11b+ dendritic cells, and interstitial macrophages to the lung was significantly suppressed, whereas Treg cells and alternatively activated macrophages increased in T spiralis infection groups vs the ovalbumin group. Notably, when T spiralis was infected prior to ovalbumin challenge, intestinal adults promoted proportions of CD103+ dendritic cells and alveolar macrophages. Conclusions T spiralis strongly suppressed type 2 inflammation, and adults maintained lung immune homeostasis. (Wenjie Shi) 14 Mar 2024
  • [hal-04318501] Chapter 89 - Anaplasma

    Anaplasma phagocytophilum is a rickettsial pathogen transmitted by ixodid ticks. A. phagocytophilum colonizes myeloid and nonmyeloid cells and causes human granulocytic anaplasmosis—an important disease in the United States, Europe, and Asia. Research has illustrated how A. phagocytophilum successfully invades and proliferates inside host cells, causing a systemic disease. Major advances have been made in understanding the molecular interactions between A. phagocytophilum and host cells. Here, we address A. phagocytophilum biology and the underlying mechanisms involved in bacterial pathogenesis and vector–pathogen interactions. Clinical features, eco-epidemiology, diagnostics, and treatment are also discussed. (Alejandro Cabezas-Cruz) 01 Dec 2023
  • [hal-04538812] Dissecting the impact of Anaplasma phagocytophilum infection on functional networks and community stability of the tick microbiome

    [...] (Patrícia Gonzaga Paulino) 09 Apr 2024
  • [hal-04398392] New insights regarding tick co-infections?

    [...] (Stefania Porcelli) 16 Jan 2024
  • [anses-04373000] Hierarchical shift of the Aedes albopictus microbiota caused by antimicrobiota vaccine increases fecundity and egg-hatching rate in female mosquitoes

    Recent studies show that mosquito–microbiota interactions affects vector competence and fitness. We investigated if host antibodies modifying microbiota impact mosquito physiology. We focused on three prevalent bacteria (Acinetobacter, Pantoea, and Chryseobacterium), originally isolated from the Asian tiger mosquito Aedes albopictus. Our goal was to assess the impact of host antibodies on mosquito microbiota and life traits. Female mosquitoes were fed with blood from rabbits immunized with each bacterium or a mock vaccine. We compared various factors, including feeding behavior, survival rates, and reproductive success of the mosquitoes. Interestingly, mosquitoes fed with blood from a Chryseobacterium-immunized rabbit showed a significant increase in fecundity and egg-hatching rate. This outcome correlated with a decrease in the abundance of Chryseobacterium within the mosquito microbiota. While no significant changes were observed in the alpha and beta diversity indexes between the groups, our network analyses revealed an important finding. The antimicrobiota vaccines had a considerable impact on the bacterial community assembly. They reduced network robustness, and altered the hierarchical organization of nodes in the networks. Our findings provide the basis for the rational design of antimicrobiota vaccines to reduce mosquito fitness and potentially induce infection-refractory states in the microbiota to block pathogen transmission. (Lourdes Mateos-Hernández) 04 Jan 2024
  • [hal-04372859] Evidence of tick-borne encephalitis virus neutralizing antibodies in Serbian individuals exposed to tick bites

    Introduction Tick-borne encephalitis (TBE) is an emerging vector-borne and food-borne disease caused by the tick-borne encephalitis virus (TBEV; Orthoflavivirus encephalitidis ), with a distribution spanning the Eurasian continent. Despite its significant public health impact in various European regions, TBE remains largely underdiagnosed in Serbia due to limited awareness and diagnostic challenges. In response to this, our study aimed to comprehensively assess TBEV exposure in individuals infested with ticks and to identify potential TBEV foci within Serbia. Materials and methods From 2019 to 2021, we conducted an observational study involving 450 patients who reported tick infestations. Results Our demographic analysis revealed a median age of 38 years, with a slight male predominance among the participants. We documented tick infestations in 38 municipalities across 14 districts of Serbia, with a notable concentration in proximity to Fruška Gora Mountain. The ticks most frequently removed were Ixodes ricinus , with nymphs and adult females being the predominant stages. On average, nymphs were removed after about 27.1 hours of feeding, while adult females remained attached for approximately 44.4 hours. Notably, we found age as a significant predictor of infestation time for both nymphs and adult females. Furthermore, we detected TBEV-neutralizing antibodies in 0.66% of the serum samples, shedding light on potential TBEV foci, particularly in Fruška Gora Mountain and other regions of Serbia. Conclusion Our study emphasizes the urgent need for active TBE surveillance programs, especially in areas suspected of hosting TBEV foci, in order to assess the true TBE burden, identify at-risk populations, and implement effective preventive measures. (Pavle Banović) 09 Apr 2024
  • [anses-04373040] Arthropod microbiota: shaping pathogen establishment and enabling control

    Vector-borne diseases (VBDs) pose significant global health threats. The microbiota of arthropod vectors influences their fitness and pathogen acquisition and/or transmission. Here, we review the intricate interplay among the arthropod immune system, the microbiota, and pathogens that limits or favors infection. We focused on the most important arthropod vectors, namely mosquitos, phlebotomines, tsetse flies, triatomines, and ticks, and expanded our analysis to include the nonvector model Drosophila melanogaster for comparison. The microbiota and immune system of arthropod vectors are targets for the development of promising control strategies, such as paratransgenesis and anti‐microbiota vaccines. Further research should focus on elucidating the underlying mechanisms of vector–pathogen–microbiota interactions and optimizing anti-microbiota strategies. These approaches have the potential to combat VBDs and reduce their global impact. (Daniel Pavanelo) 04 Jan 2024
  • [hal-04150498] Disparate dynamics of pathogen prevalence in Ixodes ricinus and Dermacentor reticulatus ticks occurring sympatrically in diverse habitats

    Ixodes ricinus and Dermacentor reticulatus ticks are important reservoirs and vectors of pathogens. The aim of the present study was to investigate the dynamic of the prevalence and genetic diversity of microorganisms detected in these tick species collected from two ecologically diverse biotopes undergoing disparate long-term climate condition. High-throughput real time PCR confirmed high prevalence of microorganisms detected in sympatrically occurring ticks species. D. reticulatus specimens were the most often infected with Francisella -like endosymbiont (FLE) (up to 100.0%) and Rickettsia spp. (up to 91.7%), while in case of I. ricinus the prevalence of Borreliaceae spirochetes reached up to 25.0%. Moreover, pathogens belonging to genera of Bartonella , Anaplasma , Ehrlichia and Babesia were detected in both tick species regardless the biotope. On the other hand, Neoehrlichia mikurensis was conformed only in I. ricinus in the forest biotope, while genetic material of Theileria spp. was found only in D. reticulatus collected from the meadow. Our study confirmed significant impact of biotope type on prevalence of representatives of Borreliaceae and Rickettsiaceae families. The most common co-infection detected in D. reticulatus was Rickettsia spp. + FLE, while Borreliaceae + R. helvetica was the most common in I. ricinus . Additionally, we found significant genetic diversity of R. raoultii gltA gene across studied years, however such relationship was not observed in ticks from studied biotopes. Our results suggest that ecological type of biotope undergoing disparate long-term climate conditions have an impact on prevalence of tick-borne pathogens in adult D. reticulatus and I. ricinus . (Zbigniew Zając) 12 Sep 2023
  • [anses-04185936] First identification of Cryptosporidium parvum virus 1 (CSpV1) in various subtypes of Cryptosporidium parvum from diarrheic calves, lambs and goat kids from 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, C. parvum genetic diversity, or 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 subtype 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 a 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. Our results point towards (i) a close association between CSpV1 movement and C. parvum movement, (ii) recent migrations of C. parvum among distantly located departments and (iii) incidental transmission of C. parvum between ruminants. 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’s role in C. parvum virulence and on subtype ability to infect different species. (Karim Tarik Adjou) 23 Aug 2023
  • [hal-04146750] Structural differences in the gut microbiome of bats using terrestrial vs. aquatic feeding resources

    Bat gut microbiomes are adapted to the specific diets of their hosts. Despite diet variation has been associated with differences in bat microbiome diversity, the influence of diet on microbial community assembly have not been fully elucidated. In the present study, we used available data on bat gut microbiome to characterize the microbial community assembly of five selected bat species (i.e., Miniopterus schreibersii , Myotis capaccinii , Myotis myotis , Myotis pilosus , and Myotis vivesi ), using network analysis. These bat species with contrasting habitat and food preferences (i.e., My. capaccinii and My. pilosus can be piscivorous and/or insectivorous; Mi. schreibersii and My. myotis are exclusively insectivorous; while My. vivesi is a marine predator) offer an invaluable opportunity to test the impact of diet on bat gut microbiome assembly. The results showed that My. myotis showed the most complex network, with the highest number of nodes, while My. vivesi has the least complex structured microbiome, with lowest number of nodes in its network. No common nodes were observed in the networks of the five bat species, with My. myotis possessing the highest number of unique nodes. Only three bat species, My. myotis , My. pilosus and My. vivesi , presented a core microbiome and the distribution of local centrality measures of nodes was different in the five networks. Taxa removal followed by measurement of network connectivity revealed that My. myotis had the most robust network, while the network of My. vivesi presented the lowest tolerance to taxa removal. Prediction of metabolic pathways using PICRUSt2 revealed that Mi. schreibersii had significantly higher functional pathway’s richness compared to the other bat species. Most of predicted pathways (82%, total 435) were shared between all bat species, while My. capaccinii , My. myotis and My. vivesi , but no Mi. schreibersii or My. pilosus , showed specific pathways. We concluded that despite similar feeding habits, microbial community assembly can differ between bat species. Other factors beyond diet may play a major role in bat microbial community assembly, with host ecology, sociality and overlap in roosts likely providing additional predictors governing gut microbiome of insectivorous bats. (Alexandra Corduneanu) 30 Jun 2023
  • [hal-04352927] Expansion des maladies à tiques, implication de la société civile dans la surveillance (sciences participatives) et développement d’outils innovants pour leur détection

    [...] (Sara Moutailler) 19 Dec 2023
  • [hal-03964649] Survey of ticks and tick-borne pathogens in wild chimpanzee habitat in Western Uganda

    Background Ticks and tick-borne pathogens significantly impact both human and animal health and therefore are of major concern to the scientific community. Knowledge of tick-borne pathogens is crucial for prescription of mitigation measures. In Africa, much research on ticks has focused on domestic animals. Little is known about ticks and their pathogens in wild habitats and wild animals like the endangered chimpanzee, our closest relative. Methods In this study, we collected ticks in the forested habitat of a community of 100 chimpanzees living in Kibale National Park, Western Uganda, and assessed how their presence and abundance are influenced by environmental factors. We used non-invasive methods of flagging the vegetation and visual search of ticks both on human team members and in chimpanzee nests. We identified adult and nymph ticks through morphological features. Molecular techniques were used to detect and identify tick-borne piroplasmids and bacterial pathogens. Results A total of 470 ticks were collected, which led to the identification of seven tick species: Haemaphysalis parmata (68.77%), Amblyomma tholloni (20.70%), Ixodes rasus sensu lato (7.37%), Rhipicephalus dux (1.40%), Haemaphysalis punctaleachi (0.70%), Ixodes muniensis (0.70%) and Amblyomma paulopunctatum (0.35%). The presence of ticks, irrespective of species, was influenced by temperature and type of vegetation but not by relative humidity. Molecular detection revealed the presence of at least six genera of tick-borne pathogens (Babesia, Theileria, Borrelia, Cryptoplasma, Ehrlichia and Rickettsia). The Afrotopical tick Amblyomma tholloni found in one chimpanzee nest was infected by Rickettsia sp. Conclusions In conclusion, this study presented ticks and tick-borne pathogens in a Ugandan wildlife habitat whose potential effects on animal health remain to be elucidated. (Camille Lacroux) 01 Mar 2023
  • [hal-04311327] Effects of Electromagnetic Radiation on Neuropeptide Transcript Levels in the Synganglion of Ixodes ricinus

    Anthropogenic electromagnetic radiation is an important environmental factor affecting the functionality of biological systems. Sensitivity to various frequencies of electromagnetic radiation has been detected in ixodid ticks in the past. However, the physiological aspects of radiation effects have not yet been studied in ticks. In the presented experiment, 360 Ixodes ricinus ticks, 180 males and 180 females, were divided into 16 irradiated and 8 control groups. The irradiated groups were exposed to two different intensities of electromagnetic radiation with a frequency of 900 MHz at different lengths of exposure time. RT-PCR was utilized to determine the changes in mRNA levels in tick synganglia after irradiation. Four randomly selected neuropeptide genes were tested-allatotropin (at), FGLa-related allatostatins (fgla/ast), kinin, and arginine-vasopressin-like peptide (avpl). A significant decrease in transcript levels in all female groups exposed to higher intensity radiofrequency radiation for 1 to 3 h was found. After one hour of radiofrequency exposure, a significant downregulation in allatotropin expression in males was detected. A consistent downregulation of the at gene was detected in males irradiated with at a higher intensity. Unfortunately, the specific functions of the studied neuropeptides in ticks are not known yet, so a more comprehensive study is necessary to describe the effects of EMF on observed neuropeptides. This study represents the first report on the effects of the abiotic environment on tick neurophysiology. (Lívia Šofrankova) 28 Nov 2023
  • [hal-04533387] Influenza aviaire : quels risques ? Conférence plénière

    [...] (Nadia Haddad) 04 Apr 2024
  • [hal-04314227] Diversity of Viruses in Ixodes ricinus in Europe including Novel and Potential Arboviruses

    Tick-borne pathogens are responsible for many vector-borne diseases in Europe, causing important problems for human and animal health. The composition of viral communities in ticks and their interactions with pathogens is little understood, especially in Eastern Europe, an area that represents a major hub for animal-arthropod vectors exchanges. In this study, we used metatranscriptomics to characterize the virome of 2,753 Ixodes ricinus ticks collected from France and Romania, focusing on viruses that could potentially have implications for human or animal health. Among the great viral diversity of viruses identified, we reported a novel strain of Tribec virus, an important human pathogen that was found in Romanian ticks. We detected viruses belonging to the Phenuiviridae and Nairoviridae families close to human and animal pathogens, suggesting that these viruses could constitute novel arboviruses. We used luciferase immunoprecipitation system targeting external viral proteins of viruses identified among the Sedoreoviridae, Phenuiviridae, and Nairoviridae families to screen serum samples from small ruminants’ exposed to tick bites. The results suggest that part (approximately 12%, 95% CI 9.1–16.2) of the small ruminant population from Danube Delta, was exposed to viruses related to bi- or tri-segmented nairoviruses, but cross-reactive viruses could not be confirmed with certainly. The strategy developed in this study serves as a key step in predicting potential new disease outbreaks and can be readily adapted to study other reservoirs, vectors, and interfaces involving susceptible hosts. (Bianca Elena Bratuleanu) 29 Nov 2023
  • [anses-04370008] First molecular characterization of Dirofilaria Immitis in Cuba

    Background Dirofilarioses are widespread diseases caused by mosquito-borne nematodes of the family Onchocercidae, genus Dirofilaria . The major etiologic agent of canine dirofilariosis in the American continent is the zoonotic parasite Dirofilaria immitis . Existing reports of filarioid nematodes in Cuba are based solely on morphological and immunological analysis which do not allow unambiguous identification and/or direct detection of causal agents. Results Here we present the molecular characterization of filarioid nematodes found in a dog in Cuba. Based on the molecular and phylogenetic analysis of the 5.8S-ITS2-28S region and cox1 gene fragments, the worms were unambiguously classified as D. immitis . Sequence analysis showed high identity of the gene fragments in this study with others previously obtained from D. immitis found in dogs, wolfs and jackals but also from mosquito vectors of D. immitis . Conclusions Further studies are guarantee to better understand the epidemiological impact of canine dirofilariosis in Cuba as well as the competence of different species of culicid mosquitoes as vectors of Dirofilaria in the country. (Lisset Roblejo-Arias) 02 Feb 2024
  • [hal-04314251] Exploring the Susceptibility of C3H Mice to Tick-Borne Encephalitis Virus Infection: Implications for Co-Infection Models and Understanding of the Disease

    Ticks and tick-borne diseases (TBDs) are increasingly recognized as a critical One Health concern. Tick-borne encephalitis (TBE), a severe neuro infection caused by the tick-borne encephalitis virus (TBEV), has emerged as a significant global public health threat. Laboratory animals, particularly mice, have played a pivotal role in advancing our understanding of TBD pathogenesis. Notably, BALB/c mice have been employed as models due to their heightened susceptibility to TBEV. However, the use of C3H mice, valued for other tick-borne pathogens, has remained unexplored for TBEV until now. This study aimed to assess the susceptibility of C3H mice to TBEV infection, laying the groundwork for future co-infection models involving TBEV and Borrelia. Experiments revealed that C3H mice are susceptible to TBEV infection through subcutaneous inoculation. While 102 PFU/mouse appeared necessary for full infection, 103 PFU/mouse induced consistent symptoms. However, subsequent assessment of ticks’ acquisition of TBEV from infected mice met with limited success, raising questions about optimal infectious doses for natural infection. These findings suggest the potential of C3H mice for studying TBEV and co-infections with other pathogens, particularly Borrelia. Further exploration of the interplay between these pathogens, their transmission dynamics, and disease severity could enhance prevention and control strategies. (Porcelli Stefania) 04 Apr 2024
  • [hal-04532595] Analysis of historical data for Trichinella proficiency testing: towards the definition of performance evaluation standards for routine laboratories

    [...] (Isabelle Vallée) 04 Apr 2024
  • [hal-04525178] Identification of Cryptosporidium parvum IIa and IId zoonotic subtype families and Cryptosporidium bovis from calves in Algeria

    Cryptosporidiosis is a significant disease in calves caused by the parasitic protist Cryptosporidium. The infection results in severe symptoms such as diarrhea, dehydration, delayed growth, and weight loss, often leading to mortality and economic losses. This study aimed to detect Cryptosporidium spp. in fecal samples from calves in five Algerian provinces. A total of 65 fecal samples from calves were collected from 12 dairy cattle farms in the north-east of Algeria. The presence of the parasites was established by microscopic screening of the oocysts following an immunofluorescence assay (IFA). IFA-positive samples were analyzed by 18S rRNA PCR-RFLP (restriction fragment length polymorphism) to determine the species. Cryptosporidium parvum was subtyped by sequence analysis of the 60 kDa glycoprotein gene. Cryptosporidium oocysts were detected microscopically in 41/65 (63%) samples, of which 26/41 (63.4%) were positive by 18S rRNA PCR-RFLP. Two Cryptosporidium species were detected in 24 samples; C. parvum (20/24) and C. bovis (4/24). C. parvum isolates from IIa and IId zoonotic subtype families were detected: IIaA16G2R1 (9/24), IIdA16G1 (4/24), and IIaA15G2R1 (1/24). Thus, calves are reservoirs of zoonotic C. parvum subtypes and represent a public health concern. (Lynda Sahraoui) 28 Mar 2024
  • [anses-04373028] Identification of <em>Cryptosporidium parvum</em> IIa and IId zoonotic subtype families and <em>Cryptosporidium bovis</em> from calves in Algeria

    Cryptosporidiosis is a significant disease in calves caused by the parasitic protist Cryptosporidium. The infection results in severe symptoms such as diarrhea, dehydration, delayed growth, and weight loss, often leading to mortality and economic losses. This study aimed to detect Cryptosporidium spp. in fecal samples from calves in five Algerian provinces. A total of 65 fecal samples from calves were collected from 12 dairy cattle farms in the north-east of Algeria. The presence of the parasites was established by microscopic screening of the oocysts following an immunofluorescence assay (IFA). IFA-positive samples were analyzed by 18S rRNA PCR-RFLP (restriction fragment length polymorphism) to determine the species. Cryptosporidium parvum was subtyped by sequence analysis of the 60 kDa glycoprotein gene. Cryptosporidium oocysts were detected microscopically in 41/65 (63%) samples, of which 26/41 (63.4%) were positive by 18S rRNA PCR-RFLP. Two Cryptosporidium species were detected in 24 samples; C. parvum (20/24) and C. bovis (4/24). C. parvum isolates from IIa and IId zoonotic subtype families were detected: IIaA16G2R1 (9/24), IIdA16G1 (4/24), and IIaA15G2R1 (1/24). Thus, calves are reservoirs of zoonotic C. parvum subtypes and represent a public health concern. (Lynda Sahraoui) 05 Jan 2024
  • [anses-04372958] Ticking off the Tick Vectors: Rhipicephalus microplus Fails to Transmit Theileria orientalis

    Theileria (T [...] (Abdul Ghafar) 09 Apr 2024
  • [anses-04369914] FRET with MoS2 nanosheets integrated CRISPR/Cas12a sensors for robust and visual food-borne parasites detection

    Recently, CRISPR/Cas associated biosensors have been shown to have great potential in sensing applications due to their high sensitivity and high base resolution. However, the signal reporter system containing two organic fluorescent dye pair is limited by high cost and less stability. In contrast, functional nanomaterials exhibit robust stability, excellent optical properties and low preparation cost, making them suitable reporters. In this study, a MoS2 nanosheets (NSs) improved CRISPR/Cas12a-based biosensing platform was constructed for the first time to detect food-borne parasites. MoS2 NSs were used as fluorescence quenchers and single-stranded DNA (ssDNA) discriminated carrier to construct CRISPR/Cas signal reporter system. The combination of recombinase polymerase amplification with MoS2 NSs modulated CRISPR/Cas12a helped achieve attomolar sensitivity for nucleic acid detection within 35 min. Moreover, the results were obtained using a portable apparatus, enabling visual detection at the point of care. The practical applicability of this biosensing platform was successfully achieved through the detection of anisakis in real samples. This study provides novel insights into exploring the feasibility of two-dimensional nanomaterials based reporter in the CRISPR/Cas12a system, as well as offers a reliable tool for on-site monitoring of parasites. (Xiuqin Chen) 09 Apr 2024
  • [anses-04309487] Functional characterization of three G protein-coupled acetylcholine receptors in parasitic nematode Trichinella spiralis

    The physiological significance of metabotropic acetylcholine receptors in parasitic nematodes remains largely unexplored. Here, three different Trichinella spiralis G protein-coupled acetylcholine receptors (TsGAR-1, -2, and -3) were identified in the genome of T. spiralis. The phylogenetic analyses showed that TsGAR-1 and -2 receptors belong to a distinct clade specific to invertebrates, while TsGAR-3 is closest to the cluster of mammalian-type muscarinic acetylcholine receptors (mAChR). The mRNA of TsGAR-1, -2, and -3 was detected in muscle larvae, newborn larvae, and adults. The functional aequorin-based assay in Chinese hamster ovary cells revealed that all three types of T. spiralis GARs trigger the Gq/11 pathway upon activation of the receptor with the acetylcholine ligand. TsGAR-1 and TsGAR-2 showed atypical affinity with classical muscarinic agonists, while TsGAR-3 was sensitive to all muscarinic agonists tested. High concentrations of propiverine antagonist blocked the activities of all three TsGARs, while atropine and scopolamine antagonists effectively inhibited only TsGAR-3. Our data indicate that the distinct pharmacological profile of TsGAR-1 and -2 receptors, as well as the phylogenetic distance between them and their mammalian orthologs, place them as attractive targets for the development of selective anthelmintic drugs interfering with nematodes’ cholinergic system. (Caina Ning) 09 Apr 2024
  • [hal-04380653] Isolation of bovine CD34+ bone marrow stem and progenitor cells using a monoclonal antibody against CD34 protein

    Background: There is currently no commercially available bovine anti-CD34 monoclonal antibody. Bovine Hematopoietic Stem and Progenitor Cells (BHSPC) isolation in vitro has had mixed results. Methods: CD34 protein sequences from multiple species were compared in silico to the bovine sequence. A suitable antibody was selected and coupled to R-PhycoErythrin (R-PE). Bone marrow samples from 7 Prim’Holstein calves were collected in EDTA and mononuclear cells were isolated using a density gradient. Antibody binding to BHSPC was monitored by flow cytometry. Labeled BHSPC were separated with anti-PE magnetic beads. Enrichment was evaluated by flow cytometry. Results and discussion: A monoclonal antibody against ovine CD34 was selected based on high homology between bovine and ovine CD34. CD34+ cells accounted for 4.4 to 27.6 % of BHSPC. Variation in CD34+ cells proportion may relate to an individual variation of positive cells in the marrow; however, polymorphism in the coding region of the protein is possible (previously described). Magnetic beads increased CD34+ cells concentration by a 1.96-fold (n = 10, σ = 0.95), but with a weak recovery rate of 1.54 % (n = 8). Conclusions: This experiment describes a new potential commercial anti-CD34 monoclonal antibody for isolation or identification of BHSPC. Although the enrichment may appear low, the increase in cell purity is sufficient for culture and immortalization. (Quentin Leroy) 08 Jan 2024
  • [hal-04525679] Communication en parasitologie vétérinaire et médicale sous le concept « One Health »

    [...] (Mohamed Mammeri) 28 Mar 2024
  • [hal-04314268] Detection of bacterial and protozoan pathogens in individual bats and their ectoparasites using high-throughput microfluidic real-time PCR

    ABSTRACT Among the most studied mammals in terms of their role in the spread of various pathogens with possible zoonotic effects are bats. These are animals with a very complex lifestyle, diet, and behavior. They are able to fly long distances, thus maintaining and spreading the pathogens they may be carrying. These pathogens also include vector-borne parasites and bacteria that can be spread by ectoparasites such as ticks and bat flies. In the present study, high-throughput screening was performed and we detected three bacterial pathogens: Bartonella spp., Neoehrlichia mikurensis and Mycoplasma spp., and a protozoan parasite: Theileria spp. in paired samples from bats (blood and ectoparasites). In the samples from the bat-arthropod pairs, we were able to detect Bartonella spp. and Mycoplasma spp. which also showed a high phylogenetic diversity, demonstrating the importance of these mammals and the arthropods associated with them in maintaining the spread of pathogens. Previous studies have also reported the presence of these pathogens, with one exception, Neoehrlichia mikurensis , for which phylogenetic analysis revealed less genetic divergence. High-throughput screening can detect more bacteria and parasites at once, reduce screening costs, and improve knowledge of bats as reservoirs of vector-borne pathogens. IMPORTANCE The increasing number of zoonotic pathogens is evident through extensive studies and expanded animal research. Bats, known for their role as reservoirs for various viruses, continue to be significant. However, new findings highlight the emergence of Bartonella spp., such as the human-infecting B. mayotimonensis from bats. Other pathogens like N. mikurensis , Mycoplasma spp., and Theileria spp. found in bat blood and ectoparasites raise concerns, as their impact remains uncertain. These discoveries underscore the urgency for heightened vigilance and proactive measures to understand and monitor zoonotic pathogens. By deepening our knowledge and collaboration, we can mitigate these risks, safeguarding human and animal well-being. (Alexandra Corduneanu) 29 Nov 2023
  • [hal-04526226] Epidemiological Study of Giardiasis and Cryptosporidiosis in the Batna region

    [...] (Hassane Benseghir) 29 Mar 2024
  • [hal-04526242] La Giardiose du chien, quelle est la conduite à tenir ? Cryptosporidium spp., Giardia duodenalis and veterinary public health

    [...] (Bruno Polack) 29 Mar 2024
  • Director: Sara Moutailler
  • Assistant Director: Delphine Le Roux
  • Assistant Director: Grégory Karadjian