Publications scientifiques de l'EnvA
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Neoehrlichia mikurensis: an emerging pathogen in Southeastern Poland - prevalence in Ixodes ricinus ticks and phylogenetic characterization
No full textInternational audienceIntroduction: Neoehrlichia mikurensis is an emerging pathogen increasingly detected in ticks, animals, and humans. The study aimed to investigate the presence and phylogenetic diversity of Ixodes ricinus ticks in the Subcarpathian Region.Material and methods: Of the 412 ticks collected from forest and meadow habitats, 240 specimens underwent molecular analysis for presence of N. mikurensis using microfluidic real-time PCR. Selected amplicons were sequenced to preform phylogenetic analysis of the groEL gene.Results: N. mikurensis infection was confirmed in 6.35% of female and 2.38% of male ticks, with no significant differences in the prevalence between habitats. Phylogenetic analysis revealed a low genetic diversity N. mikurensis.Conclusions: The findings confirm the infection of I. ricinus ticks with N. mikurensis in the studied region. The studied N. mikurensis groEL gene sequences showed low genetic variation, identical to other populations in Poland and Europe
Effects of gestational olfactory enrichment on adaptation to weaning in pigs
No full textInternational audienceIn conventional farms, the use of odours to enrich the environment, which is often poor and monotonous, may offer a simple and cost-effective strategy to enhance welfare of pigs. Furthermore, pigs are capable of prenatal olfactory learning, which is context-dependent and can have longlasting behavioural effects upon odour recall. We aimed to evaluate whether the recall of an odour perceived in a positive context during prenatal life would promote better adaptation to weaning in piglets. Fifty-four gestating sows and their piglets were used in three replicates. In each replicate, enriched sows (n=9) had access to an enriched room 3 times/week for 2h throughout gestation. The room was odourised with anise and contained a peat box, straw bedding, and odourised objects, with music or nature sounds playing continuously in the background. Each visit was paired with the voluntary ingestion of aniseed sugar cubes (525 mg of anethol/intake). Control sows (n=9) were continuously kept in their barren pen. At weaning (D28), piglets from each prenatal treatment were allocated to an anise-odourised or control non-odourised room, resulting in 4 prenatal x post-weaning treatments (n=12 pens of 4 piglets/treatment). Piglet behaviour was recorded using 5-min scan sampling for 6h/day on D28 and D29. On D25 and D29, blood cortisol and blood cell counts were measured. Feed refusals and piglets were weighted on D29, D35 and D42. Effects of prenatal treatment, post-weaning treatment, day and their interactions were analyzed using linear mixed-effect models in R. Prenatal treatment did not affect post-weaning weight gain, but compared to piglets from control sows, piglets from enriched sows ate more in the first 24h post-weaning (D29, p<0.05). On D28 and D29, they also spent more time at the feeder (p=0.004), less time exploring the enrichment materials (p=0.006) and tended to spend more time resting (p=0.06). In the odourised post-weaning room, piglets prenatally exposed to the odour spent less time displaying undesirable social behaviours than non-exposed piglets (prenatal x post-weaning treatment, p=0.04). Compared to male piglets from control sows, male piglets from enriched sows had lower blood cortisol concentrations (prenatal treatment x sex, p=0.007), and tended to have a lower neutrophil/lymphocyte ratio (prenatal treatment x sex, p=0.05) on D25 and D29. While the effects of odour recall in the post-weaning environment were limited, providing gestating sows with regular access to an enriched environment positively affected the stress-related behavioural and physiological responses of their piglets at weaning
Investigating the C2 Modulation of the Imidazo[1,2‐ a ]pyrazine‐Based Hit Compound CTN1122: Synthesis, in vitro Antileishmanial Activity, Cytotoxicity and Casein Kinase 1 Inhibition
No full textInternational audienceOur research group previously discovered CTN1122 , an imidazo[1,2‐ a ]pyrazine compound with promising antileishmanial activity against intramacrophage amastigotes of Leishmania major and L. donovani strains. CTN1122 effectively targets Leishmania casein kinase 1 (L–CK1.2) and exhibits a favorable safety profile. To further explore its chemical space, we developed a convergent strategy to modify the C2 position of the imidazo[1,2‐ a ]pyrazine core using Suzuki‐Miyaura coupling of the corresponding triflate intermediate. Among 15 newly synthesized analogs, seven derivatives featuring variously substituted phenyl rings at C2 demonstrated L–CK1.2 inhibition within micromolar to submicromolar ranges and antileishmanial activity in vitro with low cytotoxicity in macrophages. Compounds 7 d and 7 l were particularly potent, with IC 50 values of 1.25 μM and 0.92 μM against L. major , and 1.44 μM and 2.34 μM against L. donovani , respectively. They showed IC 50 L–CK1.2=0.30 μM and 0.57 μM with enhanced selectivity indices (SI=3.8 and 1.6) over the human CK1ϵ ortholog. Additionally, four C2 analogs and two C5 isomers exhibited notable antiparasitic effects without strongly inhibiting L–CK1.2, indicating a possible alternative mechanism of action. Compound 7 k displayed the highest general activity, with IC 50 values of 0.31 μM on L. major and 0.27 μM on L. donovani , coupled with favorable selectivity indexes
In silico and in vitro assessments of thio-linked pyrimidine-based compounds against Leishmania donovani
No full textInternational audienceCaused by Leishmania parasites, leishmaniases are a group of pathologies acknowledged by the World Health Organization as neglected tropical diseases. Current therapies for treating these infections count on a limited arsenal of drugs with several downsides that restrict their use, namely the development of drug resistance. Innovative medicines with improved efficacy, safety, and a lower tendence for resistance development are imperatively needed.1 Trypanothione reductase (TR) critical function in sustaining the parasite's redox machinery, converting the disulfide bond of trypanothione disulfide (TS2) into reduced trypanothione T(SH)2, makes it a promising biomolecular target in the search for novel antileishmanial compounds. This di-thiol is crucial for scavenging reactive species for Leishmania2,3, offering a potential avenue for drug development. Furthermore, TR offers several advantages, highlighting its structural resemblance to all Trypanosomatidae parasites and its absence in the mammalian host.4 In the search for improved antileishmanial options, a study discovered the potential of aryl sulfides in deactivating TR.3,5 Based on these findings, we unveil the synthesis of a library of novel thio-linked pyrimidine-based compounds applying the Buchwald–Hartwig reaction that leads to the formation of different products by changing the reaction time. Our findings from the computational studies show that all compounds interact with the residues from the NADPH-binding site, thus limiting the interaction between TR and its cofactor, NADPH. We also provide the results of all compounds' in vitro antileishmanial activity against L. donovani axenic and intramacrophage amastigotes, and their cytotoxicity against Raw 264.7 cells. Compounds IC69 and IC90 were the most effective against both forms of Leishmania, exhibiting IC50 values lower than the control, miltefosine (Figure 1)
Impacts sur la santé publique de la dynamique des populations de renards
No full textOpinion and report approved by the Expert Committee Socio-economic analysis in its plenary session on 11 May 2023 and the Expert Committee Animal health and welfare (CES SABA) in its plenary session on 06 June 2023. The French Agency for Food, Environmental and Occupational Health & Safety provides independent scientific opinions and reports. The original version of the ANSES opinion and report in French is available on the website of ANSES at https://www.anses.fr/fr/system/files/SABA2022SA0049Ra.pdf.Suggested citation: ANSES. (2023). Avis et rapport de l'Agence nationale de sécurité sanitaire de l'alimentation, de l'environnement et du travail relatif à l'évaluation des impacts sur la santé publique de la dynamique des populations de renards (Saisine 2022-SA-0049). Maisons-Alfort: ANSES, 200 p.International audienceThe Red Fox (Vulpes vulpes) can be hunted as a game species. It may also be listed as a “species likely to cause damage” (ESOD – the acronym in French), for public health reasons among others. Conversely, benefits linked to the presence of foxes are also put forward, such as the predation of rodents carrying zoonotic agents. In this context, ANSES was asked to: (1) list the zoonoses present in France for which foxes play an epidemiological role, (2) identify other public health impacts associated with changes in fox populations, (3) explain the relative importance of the effects of changes in fox populations for humans and/or the environment, (4) analyse the feasibility of a cost‐benefit analysis (CBA) of the prevention and impacts associated with these zoonoses. In France, the fox is a source of zoonotic pathogens, with a major role for Echinococcus multilocularis, a parasite for which the fox is the main source of environmental contamination. However, reducing fox populations does not reduce the risk of transmission of E. multilocularis to humans or domestic animals, and may even have the opposite effect to the one intended. The main levers for action are those relating to exposure to environmental contamination. The fox is part of complex trophic networks, in which its specific role in regulating prey populations is impossible to determine because (i) several predators share the same prey, with a variable role for the fox among the predators, (ii) the dynamics of prey populations is also conditioned by factors other than predation. The relationship between the abundance of rodents and the risk of disease for humans has not been demonstrated either, due to the complexity of the trophic and epidemiological networks, their highly probable variability from one ecosystem to another, and the multiplicity of hosts. As a result, the data currently available does not allow any conclusions to be drawn about the epidemiological role of the fox as a predator of rodents hosting zoonotic agents. Finally, there is no public health justification for culling foxes, particularly for ESOD classification, except in the very specific and localised context of the fight against bovine tuberculosis, for which the selective culling of foxes in and around the livestock buildings of a domestic outbreak has been proposed. In addition, the expertise concluded to the feasibility of a CBA targeted at assessing the burden of alveolar echinococcosis and measures to prevent its transmission. The feasibility study shows the partial nature of a CBA targeting zoonoses, without taking into account other roles played by the fox in the ecosystem
In copula depuis 1998 : description d’un couple d’Ixodes (Afrixodes)
No full textInternational audienceTrès peu étudié, le sous-genre Afrixodes, inféodé à l’Afrique tropicale, appartient au genre de tiques dures Ixodes. Ce sous genre comprend 62 espèces, représentées actuellement uniquement en Afrique (sauf 2 espèces d’Inde), dont 9 espèces endémiques de l’île de Madagascar. Or, la taxonomie de la grande majorité des espèces de ce sous genre Afrixodes reste largement à préciser. Il manque la description des mâles chez 47% des espèces de ce sous-genre, 69% pour les nymphes et 78% pour les larves. Seulement 14 espèces d’Afrixodes disposent d’au moins une séquence déposée dans Genbank (dont Cox1 & 16S). Tout ce manque d’information rend l’identification des spécimens très compliquée, d’autant que les planches de description morphologique peuvent varier d’un auteur à l’autre. C’est la problématique rencontrée ici avec 2 spécimens, mâle et femelle, conservés en alcool depuis 1998, collectés in copula sur une crocidure au Gabon. Par l’originalité de la découverte de ces spécimens, une analyse préliminaire a été réalisée par comparaison des caractères morphologiques disponibles dans les descriptions existantes d’Ixodes (Afrixodes) mais aussi par séquençage des gènes 16S et Cox1, afin d'identifier les spécimens. Malgré le peu de donnée génétique disponible sur ces espèces, le 16S nous permet de confirmer que les 2 spécimens appartiennent bien à la même espèce, tandis que le Cox1 nous les rapproche d’Ixodes rasus Neumann 1899. Faute de certaines descriptions de mâles et au vu de l’assignation par le 16S, nous ne pouvons pour le moment pas confirmer leur appartenance à cette espèce. Néanmoins, il existe un groupe d’espèce au sein du sous-genre Afrixodes, le groupe rasus, comprenant 5 espèces (I. rasus, I. pseudorasus Arthur 1957, I. muniensis Arthur et Burrow 1957, I. procaviae Arthur et Burrow 1957, I. thomasae Arthur et Burrow 1957) dont pourraient faire partie ces spécimens. De plus profondes investigations seront menées par la suite grâce au séquençage NGS
Cryptosporidium et Giardia chez les pigeons : un risque sous-estimé pour la santé publique ?
No full textInternational audienceLe pigeon domestique (Columba livia) est un oiseau largement répandu dans les milieux urbains à travers le monde. Vivant souvent à proximité des humains, cette espèce entre fréquemment en contact avec les populations humaines, ce qui favorise la transmission de nombreux agents pathogènes. Parmi ceux-ci, deux protozoaires intestinaux à transmission zoonotique se distinguent par leur fréquence chez l’Homme : Cryptosporidium spp. et Giardia duodenalis. Ces parasites représentent un enjeu sanitaire important dans le contexte de l’urbanisation croissante et du concept « Une seule santé » (One Health). Ces dernières décennies, les populations de pigeons ont significativement augmenté dans les zones urbaines et périurbaines, accentuant le risque de transmission croisée entre les oiseaux, les humains et d’autres animaux. Cryptosporidium spp. a été identifié chez les pigeons pour la première fois en Turquie en 1994, où l’infection s’était manifestée par des signes cliniques incluant de l’abattement, de la diarrhée et un plumage piqué. Depuis cette première description, de nombreuses études ont rapporté la présence de Cryptosporidium spp. chez les pigeons à travers le monde. Les méthodes de diagnostic traditionnelles (notamment la microscopie) indiquent une prévalence moyenne d’environ 14,8 %, alors que les techniques moléculaires, plus sensibles, révèlent une prévalence pouvant atteindre 28,4 %. Les données disponibles montrent que les pigeons captifs présentent une prévalence plus élevée que les pigeons sauvages. Les résultats moléculaires suggèrent une diversité génétique plus importante chez les pigeons domestiques, probablement en raison de leur proximité continue avec des sources d’infection humaines ou animales. Parmi les espèces zoonotiques identifiées chez les pigeons, Cryptosporidium parvum (42%) et C. meleagridis (18%) sont les plus fréquemment détectées. Ces espèces sont connues pour leur capacité à infecter l’homme, ce qui renforce l’importance sanitaire de la surveillance des populations de pigeons. L’analyse microscopique a également mis en évidence des variations notables dans l’intensité de l’infection, avec des charges en oocystes allant de 3 000 à 36 000 par gramme de fèces, ce qui constitue une source potentielle de contamination environnementale. Concernant Giardia spp., une étude menée en 2021 a permis son identification pour la première fois chez des pigeons. Auparavant, G. duodenalis avait été fréquemment observé chez les oiseaux aquatiques, mais sa présence chez les pigeons n’a jamais été confirmée. Cette hypothèse de réceptivité des pigeons à une infection par G. duodenalis a été renforcée suite à une infection expérimentale des pigeons, ce qui suggère leur rôle potentiel comme réservoir de ce parasite. Chez les oiseaux, cette infection peut entraîner des signes cliniques tels que la perte de poids, la diarrhée, le prurit et un plumage ébouriffé, bien que les manifestations cliniques puissent être variables selon les espèces. Plusieurs espèces et génotypes de Cryptosporidium spp. et de G. duodenalis sont considérés comme zoonotiques et ont été associés à des cas d’infections humaines, notamment chez les individus en contact fréquent avec les pigeons ou d’autres animaux (éleveurs, soigneurs, nettoyeurs de lieux publics, etc.). Cela souligne l’importance de ces oiseaux dans le cycle de transmission des parasites intestinaux entre les espèces. Bien que certaines données soient encore limitées, les pigeons apparaissent comme des réservoirs potentiels significatifs de parasites protozoaires zoonotiques. Des études complémentaires sont nécessaires pour mieux comprendre leur rôle exact dans la transmission de ces agents pathogènes, ainsi que leur pathogénicité chez les oiseaux et les humains. La prévention, la surveillance épidémiologique et le contrôle des infections à Cryptosporidium spp. et Giardia spp. chez les pigeons devraient constituer un axe de recherche en santé publique, particulièrement dans les zones densément peuplées où la cohabitation entre humains et pigeons est étroite. Dans ce cadre, le génotypage des souches isolés est nécessaire
Epigénétique transgénérationnelle chez les mammifères : Concept, faits et controverses
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Les explants intestinaux félins : modèle d’étude des interactions de Toxoplasma gondii avec la réponse immunitaire de la muqueuse de son hôte définitif.
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3D-organization and spatial localization of chromatin and epigenetic marks linked to nucleolar activity in porcine oocytes
No full textInternational audienceAbstract Previous murine studies have established that large-scale chromatin modifications upon completion of oocyte growth are associated with nucleolar transcriptional silencing. These modifications seem essential both for completion of the oocyte’s meiosis and subsequent embryonic developmental success. Investigating this putative interconnection between nucleolar transcriptional activity and spatial chromatin organization towards completion of oocyte growth in pigs, we scrutinized whether 3D chromatin organization and heterochromatin localization, along with epigenetic markers, could indicate oocyte quality and predict developmental competence of harvested porcine oocytes. Supravital brilliant-cresyl-blue (BCB) staining was used to classify porcine cumulus-oocyte-complexes (COCs) as fully grown (BCB+) or still growing (BCB-). Oocytes were analyzed via integrated 3D-immunofluorescence for nucleolar activity and heterochromatin markers, as well as 3D-DNA-FISH for specific heterochromatin sequences. Additionally, some oocytes were prepared for transmission electron microscopy (TEM). TEM revealed distinct ultrastructural differences between BCB+ and BCB- oocytes and validated BCB-staining as viable method for a rough assessment of oocyte developmental competence. Immunostaining identified all known germinal vesicle (GV) chromatin configurations (non-surrounded nucleolus (NSN), partially non-surrounded nucleolus (pNSN), partially surrounded nucleolus (pSN), surrounded nucleolus (SN)) and linked them to respective BCB categories. Nucleolar activity was detected only in NSN oocytes, predominantly from the BCB- group. Protein markers and FISH signals revealed significant 3D-organizational changes in chromatin between NSN and SN conformations, clustering around the nucleolus towards final oocyte maturation. These findings highlight an evident interconnection between nucleolar transcriptional silencing and specific 3D chromatin organization patterns, with changes in heterochromatin localization indicating completion of the oocytes’ growth phase and marking higher competency for subsequent final maturation and embryonic development