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 hosts :
- a National Reference Laboratory for food-borne parasites, excluding Echinococcus
- an WOAH collaborating centre on food-borne zoonotic parasites, which shares reference research projects with the Paralim team and carries out national and international reference activities.



30 April 2024

By: Sophie Bertrand - Clotilde Rouxel

Lisa Le Dortz thesis defence

PhD 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-04604271] Tick paralysis induced by Ixodes gibbosus: enigmatic cases in domestic mammals from Cyprus

    Ticks carry numerous pathogens that, if transmitted, can cause disease in susceptible humans and animals. The present study describes our approach on how to investigate clinical presentations following tick bites in humans. To this aim, the occurrence of major tick-borne pathogens (TBPs) in human blood samples ( n = 85) and the ticks collected ( n = 93) from the same individuals were tested using an unbiased high-throughput pathogen detection microfluidic system. The clinical symptoms were characterized in enrolled patients. In patients with suspected TBP infection, serological assays were conducted to test for the presence of antibodies against specific TBPs. A field study based on One Health tenets was further designed to identify components of a potential chain of infection resulting in Rickettsia felis infection in one of the patients. Ticks species infesting humans were identified as Ixodes ricinus , Rhipicephalus sanguineus sensu lato (s.l.), Dermacentor reticulatus , and Haemaphysalis punctata . Five patients developed local skin lesions at the site of the tick bite including erythema migrans, local non-specific reactions, and cutaneous hypersensitivity reaction. Although Borrelia burgdorferi s.l., Babesia microti , Anaplasma phagocytophilum , and Candidatus Cryptoplasma sp. DNAs were detected in tick samples, different Rickettsia species were the most common TBPs identified in the ticks. The presence of TBPs such as Rickettsia helvetica , Rickettsia monacensis , Borrelia lusitaniae , Borrelia burgdorferi , Borrelia afzelii , A. phagocytophilum , and B. microti in ticks was further confirmed by DNA sequencing. Two of the patients with local skin lesions had IgG reactive against spotted fever group rickettsiae, while IgM specific to B. afzelii , Borrelia garinii , and Borrelia spielmanii were detected in the patient with erythema migrans. Although R. felis infection was detected in one human blood sample, none of the components of the potential chain of infection considered in this study tested positive to this pathogen either using direct pathogen detection in domestic dogs or xenodiagnosis in ticks collected from domestic cats. The combination of high-throughput screening of TBPs and One Health approaches might help characterize chains of infection leading to human infection by TBPs, as well as prevalence of emerging rickettsial pathogens in the Balkan region. (Anastasia Diakou) 07 Jun 2024
  • [hal-04573144] Tick-borne zoonotic flaviviruses and Borrelia infections in wildlife hosts: what have field studies contributed?

    [...] (Armelle Poisson) 13 May 2024
  • [pasteur-04548947] Increased threat of urban arboviral diseases from Aedes aegypti mosquitoes in Colombia

    Objectives Our study targets the potential of the local urban mosquito Aedes aegypti to experimentally transmit chikungunya virus (CHIKV), dengue virus (DENV), yellow fever virus (YFV), and Zika virus (ZIKV). Methods We collected eggs and adults of Ae. aegypti in Medellín, Colombia (from February to March 2020) for mosquito experimental infections with DENV, CHIKV, YFV and ZIKV and viral detection using the BioMark Dynamic arrays system. Results We show that Ae. aegypti from Medellín was more prone to become infected, to disseminate and transmit CHIKV and ZIKV than DENV and YFV. Conclusions Thus, in Colombia, chikungunya is the most serious threat to public health based on our vector competence data. (Rosa Margarita Gélvez Ramírez) 16 Apr 2024
  • [hal-04601322] Multimodal treatment of a preauricular and palpebral Feline Bowenoid In Situ Carcinoma (BISC) in a cat : Photodynamic Therapy, caudal auricular cutaneous flap and radiotherapy

    [...] (Noëlle Cochet-Faivre) 04 Jun 2024
  • [hal-04601326] Large palpebral cystadenomatosis in a cat, successfully managed by diode laser vaporization

    [...] (Matthieu Bott) 04 Jun 2024
  • [hal-04601332] Assessment of Meibomian glands morphology and tear film quality in dogs diagnosed with idiopathic sebaceous adenitis or leishmaniosis: a pilot study

    [...] (Coline Jondeau) 04 Jun 2024
  • [anses-04604994] Giardia duodenalis in Algeria: a review within a One Health approach

    Giardia duodenalis is a protozoan parasite that primarily infects the small intestine of various mammals, including humans. It is a complex of species composed of multiple genotypes known as assemblages A to H. Assemblages A and B, which are considered the most zoonotic, pose a significant risk to human health. Assem-blages C to H are generally found in companion animals, livestock, rodents and marine vertebrates. Giardiasis, the infection caused by G.duodenalis, is the most common intestinal parasitic infection worldwide. In Algeria, the lack of data on the occurrence and genetic characteristics of G.duodenalis limits our understanding of its epidemiology, impact and zoonotic potential. This review focuses on research conducted in Algeria, covering humans, animals and the environment, with an emphasis on the “One Health” approach. PubMed and ResearchGate databases were used to access relevant publications on the presence of G.duodenalis in humans, animals and the environment from January 2000 to April 2023. Of the seventeen publications identified, only four articles used molecular tools to iden-tify G.duodenalis. The results revealed the presence of G.duodenalis in humans, livestock (cattle, sheep and camels), and the environment (water and soil sam-ples). The prevalence and genetic diversity of G.duodenalis isolates varied across regions and age groups in both humans and animals. Assemblage A was commonly found in humans and animals, indicating potential zoonotic transmission. Further studies are necessary to fully grasp the transmission dynamics, zoonotic potential and public health and animal welfare implications of G.duodenalis in Algeria. Veterinarians, biologists, ecologists and health professionals should work together to tackle G.duodenalis as part of the “One Health” approach. Implementing prevention and control strategies tailored to specific regions and improving hygiene and animal husbandry practices are vital to reduce the burden of giardiasis in both humans and animals. (Myriam Thomas) 07 Jun 2024
  • [hal-04603604] Tick paralysis induced by Ixodes gibbosus: enigmatic cases in domestic mammals from Cyprus

    Tick paralysis is a potentially fatal condition caused by toxins produced and secreted by tick salivary glands. This survey presents clinical and epidemiological observations of tick paralysis cases in domestic animals in Cyprus. Local veterinarians report typical tick paralysis cases occurring in goats, sheep, dogs, and cats. The animals suffering from paralysis are free from other neurological diseases, have blood and biochemical parameters within normal ranges, and recover fast by simply removing the ticks found predominantly on the head and around the neck. Tick paralysis cases occur in a specific geographic area of Cyprus (Akamas peninsula), from September through March, but not every year. Instead, the phenomenon has 2 periodic cycles of occurrence, a 3-and a 7-year cycle. The two cycles are differentiated by severity based on the number of affected animals and the resulting losses. As described for other tick-borne diseases, these cyclic patterns may be attributed to external factors, selfoscillations of the disease system, or the combined action of these mechanisms. Ticks collected from a recent paralysis case in a goat were morphologically and molecularly identified as Ixodes gibbosus. Efforts should be made to characterise the specific toxins involved in tick paralysis and to develop a vaccine, which could prevent significant losses of small ruminants, especially in free-ranging farming systems, a prevalent management approach observed in Cyprus and various regions worldwide. (Anastasia Diakou) 06 Jun 2024
  • [hal-04562390] Experimental Infections Reveal Acquired Zoonotic Capacity of Human Schistosomiasis Trough Hybridization

    We are currently witnessing the endemization of urogenital schistosomiasis in southern Europe. The incriminated parasite is a hybrid between a human parasite and a livestock parasite. Using an experimental evolutionary protocol, we created hybrid lines from pure strains of both parasite species. We showed that the host spectrum of the human parasite is enlarged to the livestock parasite after genomic introgression. We also evidenced that the tropism of the parasites within the host changes and that some hybrid lines are more virulent than the parental strains. These results engage a paradigm shift from human to zoonotic transmission of urogenital schistosomiasis. (Bruno Polack) 29 Apr 2024
  • [hal-04559697] Spatial Distribution and Pathogen Profile of Dermacentor reticulatus Ticks in Southeastern Poland: A Genetic and Environmental Analysis

    In recent years, significant changes have been observed in the distribution and abundance of local Dermacentor reticulatus populations. However, changes in D. reticulatus dynamics have not been studied in southeastern Poland. Our objective was to enhance our understanding of the environmental factors influencing the occurrence and density of D. reticulatus in this area. Additionally, we sought to investigate the genetic diversity of the tick population and the prevalence of tick-borne pathogens (TBPs). To this end, we established 45 study sites in the Subcarpathian province. Ticks were collected during their peak activity in both spring and autumn. A subset of randomly selected specimens underwent molecular analysis for TBPs screening, using high-throughput microfluidic real-time PCR. Positive amplicons were then sequenced, and phylogenetic analyses were conducted. Our findings confirmed the presence of D. reticulatus ticks in 24 surveyed sites, primarily concentrated in the northern and eastern parts of the region. The mean density of D. reticulatus ticks in their compact range was 5.8 ± 6.4 specimens/100 m2. Notably, air temperature and altitude emerged as significant factors influencing the species’ activity. We also identified a high prevalence of Rickettsia raoultii infections in adult D. reticulatus, reaching up to 84.21%. Additionally, 9.52% of ticks were found to be infected with R. helvetica and 4.76% with Anaplasma phagocytophilum. Furthermore, our genetic analyses confirmed the identity of D. reticulatus in the Subcarpathian region, aligning with haplotypes found in other regions of Poland, Czechia, Croatia, and Portugal. In conclusion, our study suggests that the surveyed region represents the current boundary of the compact range of D. reticulatus in Poland in which this tick species exhibits low genetic diversity and a narrow spectrum of detected TBPs. (Zbigniew Zając) 25 Apr 2024
  • [anses-04574028] Risque de transmission du virus Monkeypox par la manipulation et la consommation d'aliments

    La variole simienne est une maladie infectieuse zoonotique causée par le virus Monkeypox (MPXV), un virus à ADN enveloppé appartenant à la famille des Poxviridae et au genre Orthopoxvirus. Au printemps 2022, de nombreux cas humains ont été signalés dans des pays non endémiques, sans antécédents de contact avec des animaux importés ou de voyage dans une zone où le virus circulait habituellement. Cette évaluation qualitative des risques visait à étudier la probabilité de transmission du MPXV par les aliments lors de leur manipulation et de leur consommation. L’évaluation des risques a utilisé deux approches : (i) l’approche « descendante » (basée sur des données épidémiologiques) a d’abord conclu que la viande de brousse était le seul aliment suspecté d’être une source de contamination dans les cas enregistrés de MPXV, par contact ou par ingestion. (ii) L’approche « ascendante » (en suivant l’agent tout au long de la chaîne alimentaire pour évaluer le risque de transmission à l’humain par voie alimentaire) a évalué la chaîne d’événements nécessaires pour qu’un être humain tombe malade après avoir manipulé ou consommé des aliments. Cette approche implique plusieurs conditions : (i) l’aliment doit être contaminé par le MPXV ; (ii) avec un virus viable lorsqu’il parvient au manipulateur ou au consommateur ; (iii) la personne doit être exposée au virus et ; (iv) elle doit être infectée après exposition. Les conclusions des approches descendante et ascendante sont cohérentes et suggèrent que le risque de transmission du MPXV par les aliments reste hypothétique et qu’une telle occurrence n’a jamais été rapportée. En cas de contamination éventuelle d’un aliment, la cuisson (par exemple, 12 minutes à 70 °C) pourrait être considérée comme efficace pour inactiver les Poxviridae dans les aliments. À notre connaissance, il s’agit de la première évaluation des risques réalisée sur la transmission du MPXV par voie alimentaire. (Estelle Chaix) 13 May 2024
  • [hal-04557489] Dynamic nesting of Anaplasma marginale in the microbial communities of Rhipicephalus microplus

    Abstract Interactions within the tick microbiome involving symbionts, commensals, and tick‐borne pathogens (TBPs) play a pivotal role in disease ecology. This study explored temporal changes in the microbiome of Rhipicephalus microplus , an important cattle tick vector, focusing on its interaction with Anaplasma marginale . To overcome limitations inherent in sampling methods relying on questing ticks, which may not consistently reflect pathogen presence due to variations in exposure to infected hosts in nature, our study focused on ticks fed on chronically infected cattle. This approach ensures continuous pathogen exposure, providing a more comprehensive understanding of the nesting patterns of A. marginale in the R. microplus microbiome. Using next‐generation sequencing, microbiome dynamics were characterized over 2 years, revealing significant shifts in diversity, composition, and abundance. Anaplasma marginale exhibited varying associations, with its increased abundance correlating with reduced microbial diversity. Co‐occurrence networks demonstrated Anaplasma 's evolving role, transitioning from diverse connections to keystone taxa status. An integrative approach involving in silico node removal unveils the impact of Anaplasma on network stability, highlighting its role in conferring robustness to the microbial community. This study provides insights into the intricate interplay between the tick microbiome and A. marginale , shedding light on potential avenues for controlling bovine anaplasmosis through microbiome manipulation. (Elianne Piloto-Sardiñas) 24 Apr 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
  • [hal-04557499] Influence of microbiota-driven natural antibodies on dengue transmission

    Dengue has had a significant global health impact, with a dramatic increase in incidence over the past 50 years, affecting more than 100 countries. The absence of a specific treatment or widely applicable vaccine emphasizes the urgent need for innovative strategies. This perspective reevaluates current evidence supporting the concept of dual protection against the dengue virus (DENV) through natural antibodies (NAbs), particularly anti-α-Gal antibodies induced by the host’s gut microbiome (GM). These anti-α-Gal antibodies serve a dual purpose. Firstly, they can directly identify DENV, as mosquito-derived viral particles have been observed to carry α-Gal, thereby providing a safeguard against human infections. Secondly, they possess the potential to impede virus development in the vector by interacting with the vector’s microbiome and triggering infection-refractory states. The intricate interplay between human GM and NAbs on one side and DENV and vector microbiome on the other suggests a novel approach, using NAbs to directly target DENV and simultaneously disrupt vector microbiome to decrease pathogen transmission and vector competence, thereby blocking DENV transmission cycles. (Alejandra Wu-Chuang) 24 Apr 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-04558027] Trichinella spiralis inhibits myoblast differentiation by targeting SQSTM1/p62 with a secreted E3 ubiquitin ligase

    Trichinella spiralis infection is associated with the formation of cysts within host skeletal muscle cells, thereby enabling immune evasion and subsequent growth and development; however, the pathogenic factors involved in this process and their mechanisms remain elusive. Here, we found that Ts-RNF secreted by T. spiralis is required for its growth and development in host cells. Further study revealed that Ts-RNF functions as an E3 ubiquitin ligase that targets the UBA domain of SQSTM1/p62 by forming K63-type ubiquitin chains. This modification interferes with autophagic flux, leading to impaired mitochondrial clearance and abnormal myotube differentiation and fusion. Our results established that T. spiralis increases its escape by interfering with host autophagy via the secretion of an E3 ubiquitin ligase. (Jian Da Pang) 24 Apr 2024
  • [anses-04572758] La fièvre de West Nile: sous surveillance, même en France !

    [...] (Camille Migne) 12 May 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-04557483] Real-world evidence of rabies post-exposure prophylaxis in Serbia: Nation-wide observational study (2017–2019)

    [...] (Pavle Banović) 24 Apr 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-04557496] Importance of Probiotics in Fish Aquaculture: Towards the Identification and Design of Novel Probiotics

    Aquaculture is a growing industry worldwide, but it faces challenges related to animal health. These challenges include infections by parasites, bacteria, and viral pathogens. These harmful pathogens have devastating effects on the industry, despite efforts to control them through vaccination and antimicrobial treatments. Unfortunately, these measures have proven insufficient to address the sanitary problems, resulting in greater environmental impact due to the excessive use of antimicrobials. In recent years, probiotics have emerged as a promising solution to enhance the performance of the immune system against parasitic, bacterial, and viral pathogens in various species, including mammals, birds, and fish. Some probiotics have been genetically engineered to express and deliver immunomodulatory molecules. These promote selective therapeutic effects and specific immunization against specific pathogens. This review aims to summarize recent research on the use of probiotics in fish aquaculture, with a particular emphasis on genetically modified probiotics. In particular, we focus on the advantages of using these microorganisms and highlight the main barriers hindering their widespread application in the aquaculture industry. (Edgar Torres-Maravilla) 24 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-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-04604193] Anaplasma phagocytophilum in urban and peri-urban passerine birds in Ile-de-France

    Wild animals in general, birds in particular, play a key role in transporting ticks and propagating tick-borne pathogens. Several studies have confirmed the infection of birds with Anaplasma phagocytophilum, with overall prevalence varying widely from country to country and/or study to study. This zoonotic bacterium, transmitted mainly by ticks of the genus Ixodes, is responsible for granulocytic anaplasmosis in humans (HGA) and domestic animals (cats, dogs, horses). The disease is also called tick-borne fever (TBF) in ruminants. Extremely rare in the USA, TBF is very common in Europe, where it causes economic losses in livestock. Conversely, HGA is well established in the USA whereas only a few less severe cases have been observed in Europe. Current typing techniques support the existence of multiple variants with differences in virulence/pathogenicity and tropism for certain tick and host species. However, epidemiological cycles remain difficult to characterize in Europe. Several studies describe a cycle apparently involving only birds in Europe, but no such study has been conducted in mainland France. Our objectives were to search for A. phagocytophilum in passerine birds in the Ile-de-France region and to explore their diversity using groEL and ankA gene typing and multilocus sequence typing (MLST). Various tissues (spleen, liver, and skin) were collected from cadavers of 680 passerines between March and December 2021. The presence of A. phagocytophilum was detected by qPCR Taqman targeting the msp2 gene. Three blackbirds (Turdus merula) were found positive, representing detection rates of 0.4 % in all birds tested and 3.3 % in blackbirds. The higher frequency of detection in blackbirds could be at least partially explained by their lifestyle, as they feed on the ground. Analysis of the results of groEL and ankA typing and MLST from positive blackbirds support the hypothesis that the avian A. phagocytophilum strains in Ile-de-France are distinct from those found in mammals, and that they form their own cluster in Europe. (Clotilde Rouxel) 07 Jun 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-04562437] One world, one health, concept applied to emerging infectious diseases.

    [...] (Pascal Boireau) 29 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-04562444] An overview of emerging zoonotic and epizootic infectious diseases in Europe.

    [...] (Pascal Boireau) 29 Apr 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-04350896] Avis de l'Anses relatif à la présence de parasites Toxocara spp. dans les viandes de sanglier sauvage

    Des analyses sur les carcasses de sangliers sauvages inspectées dans les établissements français de traitement de gibiers sauvages ont révélé depuis deux ans la présence régulière de larves de Toxocara spp. Ce constat a conduit les services vétérinaires d'inspection à saisir ces carcasses, conformément à l'article 45 du règlement d'exécution (UE) n°2019/627 de la Commission du 15 mars 2019 qui prévoit que les viandes présentant une infestation parasitaire sont déclarées impropres à la consommation humaine. La problématique pour le gestionnaire est double. Le premier enjeu est lié au risque de toxocarose pour les consommateurs de viandes de sanglier et des recommandations relatives à la conservation et la cuisson des viandes à adresser aux chasseurs. Le second enjeu est relatif à la gestion des lots de sangliers détectés positifs. Les demandes instruites dans le cadre de cette expertise sont les suivantes : Demande 1 : Établir un profil de risque pour Toxocara spp. dans les viandes de sanglier sauvage. Demande 2 : Évaluer l’efficacité de traitements assainissants de la carcasse sur la viabilité du parasite Toxocara spp., plus particulièrement la congélation et la cuisson, dans le cas où ces traitements sont réalisés, soit par les établissements du secteur alimentaire, soit directement par les consommateurs. (Philippe Fravalo) 12 Mar 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
  • Director: Sara Moutailler
  • Assistant Director: Delphine Le Roux
  • Executive Assistant: Grégory Karadjian