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Autophagy machinery as exploited by viruses
No full textInternational audienceViruses adapt and modulate cellular pathways to allow their replication in host cells. The catabolic pathway of macroautophagy, for simplicity referred to as autophagy, is no exception. In this review, we discuss anti-viral functions of both autophagy and select components of the autophagy machinery, and how viruses have evaded them. Some viruses use the membrane remodeling ability of the autophagy machinery to build their replication compartments in the cytosol or efficiently egress from cells in a non-lytic fashion. Some of the autophagy machinery components and their remodeled membranes can even be found in viral particles as envelopes or single membranes around virus packages that protect them during spreading and transmission. Therefore, studies on autophagy regulation by viral infections can reveal functions of the autophagy machinery beyond lysosomal degradation of cytosolic constituents. Furthermore, they can also pinpoint molecular interactions with which the autophagy machinery can most efficiently be manipulated, and this may be relevant to develop effective disease treatments based on autophagy modulation
Impact of Environmental Stressors on Birch Pollen Allergenicity and Fertility in Northern France
No full textInternational audienceTitle: Impact of Environmental Stressors on Birch Pollen Allergenicity and Fertility in Northern France Introduction: Although its main purpose is to ensure sexual reproduction, birch pollen grain is also responsible for allergenic rhinitis and asthma, also known as pollinosis. In Northern Europe, Betula pendula is the birch species with the most allergenic pollen (P. Beck et al. 2016; G. D’Amato et al. 2007; Emberlin et al. 2002) and 96% of allergic individuals are sensitised to the protein Bet v1, the most abundant allergen of birch pollen grain (Jarolim et al. 1989; Raith and Swoboda 2023). Alteration of pollen fertility, changes of protein and lipid content, modifications of the chemical composition of the surface of pollen grains (I. Beck et al. 2013; Bychkova and Khlebova 2019; Cerceau-Larrival et al. 1990; Franze et al. 2005; Ramírez-Aliaga et al. 2022) : numerous studies highlight the interactions between atmospheric pollutants and pollen grains (Sénéchal et al. 2015). In addition, many studies have highlighted the exacerbation of pollen allergies symptoms by atmospheric pollution (Bowler and Crapo 2002; Burte et al. 2020; Gennaro D’Amato et al. 2016; Lubitz et al. 2010). For example, pollen grains can be contaminated after their release during pollination, by the coagulation of atmospheric particles on their surface (Choël et al. 2022), Numerous previous studies have shown translocation of contaminants through the roots and leaves (Alagić et al. 2013; Kosiorek et al. 2016; Kozlov et al. 1995; Luo et al. 2019). Reversely, research literature about the contamination of pollen prior to anthesis by the translocation of metal contaminants is scarce. In fact, some recent studies were interested in the impacts of pollution on the tree health as well the allergenicity of its pollen before release (Stawoska et al. 2023; Ziemianin et al. 2021). Makuch-Pietraś et al. (2023) have in this way studied trace metals accumulation in soil, leaves, sap, and pollen showing that pollen harvested prior to release contain trace metals To our knowledge, hey have quantified trace metals in birch catkins for the first time. Also, Ziemianin et al. (2021) also showed that tree pollen from areas with high levels of particulate matter were more allergenic than pollen from areas with low levels of particulate matter.Aim of the study: Birch trees are widespread in Northern France, a densely populated, highly urbanised and industrialised region. For these reasons, the goal of my thesis is to assess the impact of specific environmental stressors in Northern France on the pollen grains allergenicity and fertility. To do so, we aim to characterize the pollution at the vicinity of the trees and to know the state of the pollen from the trees. The followed study shows preliminary results and the establishment of a germination protocol. Material and method: The first step was to identify contrasting sampling sites with issues specific to the region. Once the trees were selected, the soil was sampled at the foot of the tree and pollen was collected from the catkins. To characterise the environment at the vicinity of the trees, the heavy metal content in soil was quantify using Inductively Coupled Plasma Mass Spectrometry. To determine the state of the pollen, we measured its allergenicity pollination by quantifying the allergen bet v 1 in each sample. Also, the pollen fertility can be assessed by counting the germination rate of the pollen. As pollen grains need rehydration and nutrients, germination protocol has been set up to obtain the best results of germination rate so that all factors are controlled to compare pollen fertility of each tree. Results: A total of 97.28 g of pollen from 12 birch trees was harvested at 6 sites different sites in Northern France. Samples were taken at 2 urban sites (localised in a metropolitan area), 2 industrial sites (a brownfield and an active metallurgical industrial site) and 2 rural sites (one near a slag heap and one in countryside). As the pollen samples had been stored at -80°C, they had to be thawed before being rehydrated. The results show that the germination rate is the highest when thermal shocks are avoided, i.e. a gradual return to room temperature is recommended. Moreover, pollen germination kinetics experiments have also shown that the rate of germinated pollen stagnates after 4 hours. After this period, the pollen tubes continue to elongate and tangle, making image analysis unworkable.The average Bet v1 concentration in the pollen samples are 91 091ng/10mg of pollen from rural sites, 66 942ng/10mg of pollen from urban sites and 77 811ng/10mg of pollen from industrial sites. Means concentrations of heavy metals in soil show a very high levels of Cu, Zn, Pb, Cd, Se and As in industrial sites : Cu : 299 mg.kg-1, Zn : 8754 mg.kg-1, Pb : 859 mg.kg-1, Cd : 42 mg.kg-1, Se : 5.6 mg.kg-1, As : 141 mg.kg-1; followed by rural sites : Cu : 65 mg.kg-1, Zn : 235 mg.kg-1, Pb : 105 mg.kg-1, Cd : 0.46 mg.kg-1, Se : 1.3 mg.kg-1, As : 24 mg.kg-1; and then urban sites Cu : 33 mg.kg-1, Zn : 145 mg.kg-1, Pb : 101 mg.kg-1, Cd : 0,9 mg.kg-1, Se : 0.4 mg.kg-1, As : 11 mg.kg-1. Conclusion: In conclusion, preliminary results show that despite the high concentrations of heavy metals in the industrial soils, allergenicity of pollen from tree growing on this such sites doesn’t show higher concentration of the allergen Bet v1. One of the reasons for these results may be the robustness of birch, which means it can grow in metal-rich soils without being impacted. Another next analysis will be to quantify heavy metal content in pollen samples to know if heavy metal in soil could influence heavy metal concentration in pollen grain in catkins. However, IgE reactivity of birch pollen-sensitized patients will be measured to assess allergenic risk for each pollen sample. The germination tests now allow us to assess the ability of pollen to germinate under optimum conditions and to observe differences in germination rate between the sampling sites. Acknowledgements :The authors thank the University of Lille and the Institut de Recherches Pluridisciplinaires en Sciences de l’Environnement (IREPSE Fed 4129) for financial support. The CaPPA project (Chemical and Physical Properties of the Atmosphere) is funded by the French National Research Agency (ANR) through the PIA (Programme d’Investissement d’Avenir) under contract ANR-11-LABX-005-01. The authors thank the Région Hauts-de-France, the Ministère de l ’Enseignement Supérieur et de la Recherche and the European Fund for Regional Economic Development for their financial support to the CPER CLIMIBIO and ECRIN programs.Bibliography:Alagić, S. Č., Šerbula, S. S., Tošić, S. B., Pavlović, A. N., & Petrović, J. V. (2013). Bioaccumulation of Arsenic and Cadmium in Birch and Lime from the Bor Region. Archives of Environmental Contamination and Toxicology, 65(4), 671–682. https://doi.org/10.1007/s00244-013-9948-7Beck, I., Jochner, S., Gilles, S., McIntyre, M., Buters, J. T., Schmidt-Weber, C., et al. (2013). High Environmental Ozone Levels Lead to Enhanced Allergenicity of Birch Pollen. PloS one, 8(11), e80147.Beck, P., Caudullo, G., de Rigo, D., & Tinner, W. (2016). Betula pendula, Betula pubescens and Other Birches in Europe: Distribution, Habitat, Usage and Threats. In J. San-Miguel-Ayanz, D. de Rigo, G. Caudullo, T. Houston Durrant, & A. Mauri (Eds.), European Atlas of Forest Tree Species (pp. 70–73). Luxembourg: Publication Office of the European Union. https://w3id.org/mtv/FISE-Comm/v01/e010226. Accessed 11 December 2020Bowler, R. P., & Crapo, J. D. (2002). Oxidative stress in allergic respiratory diseases. Journal of Allergy and Clinical Immunology, 110(3), 349–356. https://doi.org/10.1067/mai.2002.126780Burte, E., Leynaert, B., Marcon, A., Bousquet, J., Benmerad, M., Bono, R., et al. (2020). Long-term air pollution exposure is associated with increased severity of rhinitis in 2 European cohorts. Journal of Allergy and Clinical Immunology, 145(3), 834-842.e6. https://doi.org/10.1016/j.jaci.2019.11.040Bychkova, O. V., & Khlebova, L. P. (2019). Effects of air temperature, humidity and air pollution on fertility of birch pollen in urban environments. Ukrainian Journal of Ecology, 9(3), 346–351. https://doi.org/10.15421/2019_103Cerceau-Larrival, M. T., Nilsson, S., Berggren, B., Carbonnier-Jarreau, M.-C., Derouet, L., & Verhille, A.-M. (1990). Influence de l’environnement sur les pollens de Betula verrucosa Ehrl. Bulletin de la Société Botanique de France. Actualités Botaniques, 137(2), 137–143.Choël, M., Ivanovsky, A., Roose, A., Hamzé, M., Blanchenet, A.-M., & Visez, N. (2022). Quantitative Assessment of Coagulation of Atmospheric Particles Onto Airborne Birch Pollen Grains. Journal of Aerosol Science, 161, 105944. https://doi.org/10.1016/j.jaerosci.2021.105944D’Amato, G., Cecchi, L., Bonini, S., Nunes, C., Annesi-Maesano, I., Behrendt, H., et al. (2007). Allergenic pollen and pollen allergy in Europe. Allergy, 62(9), 976–990. https://doi.org/10.1111/j.1398-9995.2007.01393.xD’Amato, Gennaro, Pawankar, R., Vitale, C., Lanza, M., Molino, A., Stanziola, A., et al. (2016). Climate Change and Air Pollution: Effects on Respiratory Allergy. Allergy, Asthma & Immunology Research, 8(5), 391. https://doi.org/10.4168/aair.2016.8.5.391Emberlin, J., Detandt, M., Gehrig, R., Jaeger, S., Nolard, N., & Rantio-Lehtimäki, A. (2002). Responses in the Start of Betula (birch) Pollen Seasons to Recent Changes in Spring Temperatures Across Europe. International Journal of Biometeorology, 46(4), 159–170. https://doi.org/10.1007/s00484-002-0139-xFranze, T., Weller, M. G., Niessner, R., & Poschl, U. (2005). Protein Nitration by Polluted Air. Environmental Science & Technology, 39(6), 1673–1678. https://doi.org/10.1021/es0488737Jarolim, E., Rumpold, H., Endler, A. T., Ebner, H., Breitenbach, M., Scheiner, O., & Kraft, D. (1989). IgE and IgG antibodies of patients with allergy to birch pollen as tools to define the allergen profile of Betula verrucosa*. Allergy, 44(6), 385–395. https://doi.org/10.1111/j.1398-9995.1989.tb04169.xKosiorek, M., Modrzewska, B., & Wyszkowski, M. (2016). Levels of selected trace elements in Scots pine (Pinus sylvestris L.), silver birch (Betula pendula L.), and Norway maple (Acer platanoides L.) in an urbanized environment. Environmental Monitoring and Assessment, 188(10), 598. https://doi.org/10.1007/s10661-016-5600-0Kozlov, M. V., Haukioja, E., Bakhtiarov, A. V., & Stroganov, D. N. (1995). Heavy metals in birch leaves around a nickel-copper smelter at Monchegorsk, northwestern Russia. Environmental Pollution, 90(3), 291–299. https://doi.org/10.1016/0269-7491(95)00027-OLubitz, S., Schober, W., Pusch, G., Effner, R., Klopp, N., Behrendt, H., & Buters, J. T. M. (2010). Polycyclic Aromatic Hydrocarbons from Diesel Emissions Exert Proallergic Effects in Birch Pollen Allergic Individuals Through Enhanced Mediator Release from Basophils. Environmental Toxicology, 25(2), 188–197. https://doi.org/10.1002/tox.20490Luo, X., Bing, H., Luo, Z., Wang, Y., & Jin, L. (2019). Impacts of atmospheric particulate matter pollution on environmental biogeochemistry of trace metals in soil-plant system: A review. Environmental Pollution, 255, 113138. https://doi.org/10.1016/j.envpol.2019.113138Makuch-Pietraś, I., Grabek-Lejko, D., Górka, A., & Kasprzyk, I. (2023). Antioxidant activities in relation to the transport of heavy metals from the soil to different parts of Betula pendula (Roth.). Journal of Biological Engineering, 17(1), 19. https://doi.org/10.1186/s13036-022-00322-8Raith, M., & Swoboda, I. (2023). Birch pollen—The unpleasant herald of spring. Frontiers in Allergy, 4, 1181675. https://doi.org/10.3389/falgy.2023.1181675Ramírez-Aliaga, P., Foyo-Moreno, I., & Cariñanos, P. (2022). Effects of Environmental Stress on the Pollen Viability of Ornamental Tree-Species in the City of Granada (South-Eastern Spain). Forests, 13(12), 2131. https://doi.org/10.3390/f13122131Sénéchal, H., Visez, N., Charpin, D., Shahali, Y., Peltre, G., Biolley, J.-P., et al. (2015). A Review of the Effects of Major Atmospheric Pollutants on Pollen Grains, Pollen Content, and Allergenicity. The Scientific World Journal, 2015, 1–29. https://doi.org/10.1155/2015/940243Stawoska, I., Myszkowska, D., Oliwa, J., Skoczowski, A., Wesełucha-Birczyńska, A., Saja-Garbarz, D., & Ziemianin, M. (2023). Air pollution in the places of Betula pendula growth and development changes the physicochemical properties and the main allergen content of its pollen. PLOS ONE, 18(1), e0279826. https://doi.org/10.1371/journal.pone.0279826Ziemianin, M., Waga, J., Czarnobilska, E., & Myszkowska, D. (2021). Changes in Qualitative and Quantitative Traits of Birch (Betula pendula) Pollen Allergenic Proteins in Relation to the Pollution Contamination. Environmental Science and Pollution Research. https://doi.org/10.1007/s11356-021-13483-
Enhanced Siglec-8 and HLA-DR and Reduced CRTH2 Surface Expression, Highlight a Distinct Phenotypic Signature of Circulating Eosinophils in Atopic Dermatitis.
No full textInternational audienceAtopic dermatitis (AD) as well as other type 2 immune response (T2) diseases are often linked to elevated eosinophil (Eos) levels in the blood. Although the role of Eos in AD pathophysiology is suspected, it remains unclear. The development of new treatments targeting the T2 response, particularly cytokines involved in Eos activation and chemotaxis, makes it necessary to identify potential Eos profiles in AD that may respond to these treatments. A prospective study was conducted comparing blood Eos phenotypes in moderate-to-severe AD patients (n=19) without recent systemic treatment to healthy individuals (HI, n=19). The primary outcome was the membranous phenotypic signature of Eos, assessed by flow cytometry. Most AD patients (84%) had early onset in childhood, a severe disease (mean SCORAD of 57.5), and elevated blood Eos counts (310 per µl in AD vs 120 in HI, p<0.0001). AD patients exhibited lower CRTH2 on Eos but higher levels of HLA-DR and Siglec-8 compared to HI. Other surface proteins showed no significant differences. Clustering analysis confirmed increased Siglec-8 in AD patients. Additionally, AD patients had higher serum levels of T2 immune response-markers as eotaxin-2, IL-5, IL-3, and TARC. Circulating Eos in AD patients show a distinct phenotypic profile, suggesting a role in AD pathophysiology and potential involvement in differential treatment responses
Efficacy and Safety of Epicutaneous Immunotherapy in Peanut-Allergic Toddlers: Open-Label Extension to EPITOPE
No full textInternational audienceWhat is already known about this topic? In the EPITOPE study, 12 months of treatment with the VIASKIN patch containing 250 mg of peanut protein (VP250) versus placebo resulted in a statistically significant treatment effect (desensitization) in peanut-allergic children aged 1 through 3 years with a well-tolerated safety profile consistent with prior clinical trials.What does this article add to our knowledge? After 24 months of VP250 treatment, there was continued enhancement of the treatment effect without additional reports of treatment-related anaphylaxis. Results of the original placebo-treated participants mirrored the initial EPITOPE findings after 12 months of VP250 treatment.How does this study impact current management guidelines? Data from open-label extension and placebo crossover participants demonstrate the potential of VP250 to be a safe and efficacious treatment option for the management of young peanut-allergic children, if approved
Could electrohypersensitivity be a specific form of high sensory processing sensitivity?
No full textInternational audienceIntroduction Electrohypersensitivity (EHS) refers to a syndrome in which individuals claim to suffer from a variety of symptoms that they attribute to electromagnetic fields. The characteristics of this specific hypersensitivity, particularly in terms of symptoms, are similar to those associated with high sensory processing sensitivity (HSPS). This article raises the question of the superposition of these two types of sensitivity and investigates the existence of a link between the two. Methods Participants ( n = 100) completed a questionnaire measuring EHS and HSPS, as well as absorption, risk perception and avoidance strategies related to electromagnetic fields, and anxiety and depressive disorders. Results They showed an overrepresentation of highly sensitive people within the electrohypersensitive group. Furthermore, the results showed differences in terms of anxiety-depressive symptomatology and cognitive strategies (risk perception and avoidance strategies). Discussion The article discusses these results in the light of the literature and suggests avenues for future research and ways to help highly sensitive people, whether wor not this condition is considered to be caused by electromagnetic radiation
Visualizing Intracellular Sialylation with Click Chemistry and Expansion Microscopy
No full textInternational audienceSummaryHere, we propose a simple protocol combining metabolic oligosaccharide engineering, click chemistry, and expansion microscopy that allows bioimaging of intracellular sialylated N-glycoproteins with improved resolution using routine microscopy equipment.AbstractMetabolic labeling techniques allow the incorporation of bioorthogonal reporters into glycans, enabling the targeted bioconjugation of molecular dyes within cells through click and bioorthogonal chemistry. Metabolic oligosaccharide engineering (MOE) has attracted considerable interest due to the essential role of glycosylation in numerous biological processes that involve molecular recognition and its impact on pathologies ranging from cancer to genetic disorders to viral and bacterial infections.Although MOE is better known for the detection of cell surface glycoconjugates, it is also a very important methodology for the study of intracellular glycans in physiological and pathological contexts. Such studies greatly benefit from high spatial resolution. However, super-resolution microscopy is not readily available in most laboratories and poses challenges for daily implementation. Expansion microscopy is a recent alternative that enhances the resolution of microscopy by physically enlarging biological specimens labeled with fluorescent markers. By embedding the sample in a swellable gel and causing it to expand isotropically through chemical treatment, subcellular structures can be visualized with enhanced precision and resolution without the need for super-resolution techniques.In this work, we illustrate the capacity of expansion microscopy to visualize intracellular sialylated glycans through the combined use of MOE and click chemistry. Specifically, we propose a procedure for bioorthogonal labeling and expansion microscopy that employs a reporter targeting sialylation, which may be associated with immunofluorescence for co-localization studies. This protocol enables localization studies of sialoconjugate biosynthesis, intracellular trafficking, and recycling
Isolation and characterization of Acinetobacter phage vAbaIN10 active against carbapenem-resistant Acinetobacter baumannii (CRAB) isolates from healthcare-associated infections in Dakar, Senegal
No full textInternational audienceBackground: Carbapenem-resistant Acinetobacter baumannii (CRAB) is a critical antimicrobial resistance threat and a WHO-prioritized pathogen. With intrinsic resistance to multiple antibiotics and the emergence of pan-resistant isolates, CRAB infections are challenging to treat, often relying on polymyxins, tigecycline, aminoglycosides, or combinations, though co-resistance is rising globally. Phage therapy is considered as a potential treatment for multidrug-resistant A. baumannii . This study focused on isolating and characterizing phages active against CRAB strains from healthcare-associated infections in Dakar, Senegal.Methods: A lytic phage, Acinetobacter vAbaIN10, was isolated from wastewater collected at the Aristide Le Dantec Hospital in Dakar, Senegal. Isolation, host range, efficiency of plating, temperature and pH stability, lysis kinetics, one-step growth test, sequencing, and genomic analysis were performed.Results: Phage vAbaIN10 belongs to the class Caudoviricetes and the genus Friunavirus . Its genome is 40,279 bp in size. Phage vAbaIN10 is stable across a wide pH range (3-9) and temperature range (25 °C-60 °C). The phage's lytic activity was evaluated at different multiplicities of infection (MOI): MOI 10, 1, and 10 -¹. All MOIs significantly reduced the growth of host bacteria. The one-step growth curve showed that vAbaIN10 had a latency period of 25 min and a burst size of approximately 4.78 × 10 ³ phages per infected bacterial cell. No tRNA, mtRNA, clustered regularly interspaced short palindromic repeat, virulence factors, or antibiotic resistance genes were found in the genome.Conclusions: The biological and genomic characteristics of vAbaIN10 meet the requirements for its potential use in phage therapy
Discovery of New Nanomolar Selective IRAP Inhibitors
No full textInternational audienceAmong the M1 family of oxytocinase aminopeptidases, insulin-regulated aminopeptidase IRAP, is an emerging drug target implicated in various biological pathways and particularly in MHC-I antigen presentation through amino-terminal trimming of exogenous cross-presented peptides. A few series of inhibitors inspired either by angiotensin IV, one of IRAP substrates, or by bestatin a pan aminopeptidase inhibitor, have been disclosed. However, the variety and number of chemotypes remains relatively limited. Here we disclose the design and optimization of a series of hydroxamic acids IRAP inhibitors bearing a 5-substituted indole. Docking studies of the best compound 43 (BDM_92499), a single-digit nanomolar and selective inhibitor of IRAP, suggest an original binding mode and highlight the substituent on the indole and a primary amide as groups driving selectivity. Several inhibitors in the series displayed IRAP-dependent inhibition of antigen cross-presentation. These results pave the way to the development of novel therapeutic agents targeting IRAP
Rapid-sequence clinical research before and during a pandemic: Lessons learned and the way forward
No full textInternational audienceIn the aftermath of the COVID-19 pandemic, the structuring of a nationwide research network for preparation and response to emerging infectious diseases (EID) with epidemic or pandemic potential has become increasingly essential. A nationwide EID operational research network (OPEN-ReMIE),is funded for five years through the France 2030 program and run by the French national research agency (ANR). Its primary missions are to accelerate hospital-based clinical research under epidemic or pandemic conditions with academic or industrial sponsors, and to pursue this effort in international research networks. OPEN-ReMIE governance is geared to steering this network and to guaranteeing its operability in inter- as well as crisis modes. It will be the point of entry for key international trial platforms, academic and private sponsors, regulatory agencies, associations of citizens and patients, and think tanks committed to promoting scientific integrity. OPEN-ReMIE encompasses six work packages: (i) regulatory affairs, sponsoring, fast-track procedures and contracts; (ii) clinical site network management; (iii) methodology and management centers to provide methodological expertise (generic master protocols, sets of core and extended variable catalogs, electronic case reports form templates, data management and interoperability, monitoring…); (iv) laboratory and biological resource center management; (v) drug supply and pharmacovigilance supervisory board; (vi) training programs and communication plans for various stakeholders: research teams, healthcare professionals, students, associations of citizens and patients and, increasingly, civil society actors. All in all, OPEN-ReMIE is a nationwide \"preparedness task force\" embedded in a large-scale European consortium for EID clinical research and working with other international EID clinical research platforms
First assessment of plague in terrestrial small mammals and fleas from Makira Natural Park and surroundings, North-eastern Madagascar
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/615854/) * Autres projets (id;sigle;titre): ;SWM Programme;(EU) Sustainable Wildlife Management Programme//International audienceBackground: Plague, a zoonosis caused by Yersinia pestis, is endemic in Madagascar but knowledge on the epidemiological situation in the northern focus remains unclear. The aim of this study was to investigate the circulation of Y. pestis in terrestrial small mammals in north eastern Madagascar, where suspected plague outbreaks have been reported. Methods: Sampling of terrestrial small mammals and their fleas was carried out in 22 trapping sites within 9 localities of the two sectors (1 and 3) of Makira Natural Park (MNP) and surroundings, from 2020 to 2022. Yersinia pestis was investigated in terrestrial small mammal spleen samples and their fleas using bacteriological, serological and molecular methods. Results: A total of 614 terrestrial small mammals composed of eight species and 1,754 individual fleas were collected following 4,880 trap-nights. The black rat (Rattus rattus) represented the majority (87.8%) of the small mammal species caught. Flea infestation rate was higher in sector 3 compared to sector 1. In sector 3, Xenopsylla brasiliensis, a plague vector, represented 66.4% of fleas identified. Further, one plague seropositive R. rattus individual, captured inside a house, and one Ctenocephalides felis specimen, collected on another R. rattus, was positive on PCR in this sector. Discussion: Despite low detection rates, we confirmed the circulation of Y. pestis in our study area (one rat seropositive and one flea PCR positive) and highlight the risk of potential human transmission. Our results also suggest that R. rattus contributes to the maintenance and transmission of plague in MNP, as described for other areas in Madagascar. Further, these findings contribute to documentation of the known geographic distribution of the endemic plague vector S. fonquerniei and X. brasiliensis. Conclusion: The confirmation of the circulation of the Y. pestis through serological and molecular diagnostics in small mammals and fleas underscores the urgent need to assess awareness levels of risk factors and symptoms to monitor among local communities and health workers and ensure that trained rapid response teams are prepared to intervene promptly upon suspect case detection. The risk and epidemiology of plague circulation in remote rural areas of Madagascar remains insufficiently studied. Addressing this gap is crucial, as a more comprehensive understanding of the distribution and dynamics of the wild animal hosts, their vectors and host-vector interactions will enhance risk assessment and prevention for plague emergence and improve mitigation and early control of potential outbreaks