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Advances in surveillance and control methods for Aedes-borne diseases and urban vectors: report of the International Conference, August 2024, Tanzania
No full textInternational audienceVector-borne diseases, particularly arboviral diseases transmitted by mosquitoes (e.g. dengue, Zika and chikungunya), have (re)emerged globally with increasing prevalence and severity. Climatic and environmental changes have resulted in significant expansion of the geographical distribution of Aedes mosquito vectors to unprecedented levels, creating optimal conditions for their introduction and establishment in new areas, especially in Africa. The prevention of Aedes -borne diseases relies heavily on controlling vector populations. However, the global resurgence of dengue underscores the limitations of current vector control tools in preventing epidemics, highlighting the urgent need for affordable, scalable and community-based vector control measures to address Aedes -borne diseases and urban mosquito vectors (e.g. Aedes spp. and Anopheles stephensi ), with the overall aim to improve public health and well-being. In this report, we summarize the main outcomes of the “International conference on advances in surveillance and control methods for Aedes -borne diseases and urban vectors” held in Dar es Salaam, Tanzania, 26–28 August 2024. The conference aimed to facilitate knowledge exchange, promote collaborative research and drive innovation in the surveillance and control of Aedes -borne diseases in Africa. Key objectives included reviewing the performance of new tools and technologies for Aedes control, and fostering inter-sectoral and international collaborations to strengthen public health measures against mosquito-borne diseases. The event was attended by more than 200 participants from 20 nationalities/countries and was streamed live online, with 321 virtual accesses recorded during the 3-day event
Revealing trends in measles immunity during periods of varying measles circulation in Madagascar
No full textInternational audienceEstimating the durability of immunity from vaccination is complicated by unreported re-vaccination, and unobserved natural infection or reexposure, which could result in overestimation of protection longevity. We tested serial cross-sectional serum samples from 2005 to 2015 (N=2,530) for IgG to examine measles seroprevalence, spatiotemporal patterns of titers across regions and antibody dynamics among children aged 1-9 years who grew up during varying measles circulation in Madagascar under a one-dose vaccination schedule. We found that measles seroprevalence has generally decreased over this time period. Furthermore, we conducted two nested serological surveys, analyzing 393 samples taken in 2005 (N=158), a time-point preceded by high levels of measles circulation, and 2015 (N=235), a time-point preceded by low levels of measles circulation. Among children alive during periods of limited measles circulation, we found lower measles seroprevalence in all age groups and lower antibody titers in children aged 7-9 years old. Notably, titers among children aged 7-9 dipped near the threshold of protection, highlighting the importance of additional measles vaccine doses. Our findings suggest that vulnerabilities might emerge during periods of limited measles circulation for countries with a one-dose schedule due to both the build-up of susceptible individuals and waning titers
Diversity and seasonality of ectoparasite burden on two species of Madagascar fruit bat, Eidolon dupreanum and Rousettus madagascariensis
No full textPosted January 22, 2025 on bioRxiv.International audienceBackground Bats are important reservoir hosts for a variety of microparasites, some of which are transmitted by ectoparasite vectors that include mites, fleas, lice, ticks, and bat flies (families Nycteribiidae and Streblidae). All of these ectoparasite taxa are known to parasitize two endemic fruit bats of Madagascar, Eidolon dupreanum and Rousettus madagascariensis. We aimed to describe the diversity of ectoparasite infestation for both bat species through morphological observation and DNA barcoding and elucidate ecological and climatic correlates of seasonal nycteribiid parasitism of these hosts.Methods Live E. dupreanum and R. madagascariensis fruit bats were captured monthly in northern and central-eastern Madagascar from 2013-2020. Ectoparasites on all captured bats were counted and identified in the field, then collected into ethanol. Field identification of a subset of samples were confirmed via microscopy and DNA barcoding of the cytochrome C oxidase subunit 1 (COI) and 18S genes. The seasonal abundance of nycteribiid bat flies on both host bats was analyzed using generalized additive models, and the role of climate in driving this seasonality was assessed via cross-correlation analysis combined with generalized linear models. Phylogenetic trees were generated to compare COIand 18S sequences of Madagascar nycteribiid and streblid bat flies with available reference sequences from GenBank.Results Ectoparasites corresponding to four broad taxa (mites, ticks, fleas, and bat flies) were recovered from 628 of 873 E. dupreanum and 831 of 862 R. madagascariensis . E. dupreanum were most commonly parasitized by Cyclopodia dubia nycteribiids and R. madagascariensis by Eucampsipoda madagascariensis nycteribiids or Megastrebla wenzeli streblids. We observed significant seasonality in nycteribiid abundance on both bat hosts, which varied by bat sex and was positively correlated with lagged temperature, precipitation, and humidity variables. Barcoding sequences recovered for all three bat fly species grouped with previously reported sequences, confirming morphological species identification. Our study contributes the first DNA barcodes of any kind reported for M. wenzeli and the first 18S barcodes for C. dubia .Conclusion This study explores the diversity and abundance of ectoparasite burdens in two Malagasy fruit bat species, highlighting the importance of seasonal ecology and the influence of climate variables on parasitism, which correlates with resource availability
Biliary tract cancers: addressing healthcare disparities and improving access to innovative treatments in Europe
No full textInternational audienc
A coronavirus assembly inhibitor that targets the viral membrane protein
No full textInternational audienceThe coronavirus membrane protein (M) is the main organizer of coronavirus assembly1,2,3. Here, we report on an M-targeting molecule, CIM-834, that blocks the assembly of SARS-CoV-2. CIM-834 was obtained through high-throughput phenotypic antiviral screening followed by medicinal-chemistry efforts and target elucidation. CIM-834 inhibits the replication of SARS-CoV-2 (including a broad panel of variants) and SARS-CoV. In SCID mice and Syrian hamsters intranasally infected with SARS-CoV-2, oral treatment reduced lung viral titres to nearly undetectable levels, even (as shown in mice) when treatment was delayed until 24 h before the end point. Treatment of infected hamsters prevented transmission to untreated sentinels. Transmission electron microscopy studies show that virion assembly is completely absent in cells treated with CIM-834. Single-particle cryo-electron microscopy reveals that CIM-834 binds and stabilizes the M protein in its short form, thereby preventing the conformational switch to the long form, which is required for successful particle assembly. In conclusion, we have discovered a new druggable target in the replication cycle of coronaviruses and a small molecule that potently inhibits it
Impact of obesity on outcomes following surgery for gastric adenocarcinoma: A European multi-institutional study
No full textInternational audienc
Characterization of the natural bacterial microbiota of pathogenic free-living amoebae (Acanthamoeba spp. and Naegleria fowleri) isolated from rivers and tap water in Guadeloupe
No full textInternational audienceFree-living amoebae (FLA) are ubiquitous protists found in water, feeding mainly on bacteria. While most FLA are harmless, Acanthamoeba spp. and Naegleria fowleri can cause keratitis and/or meningitis. FLA can host amoeba-resistant bacteria (ARB), but their natural bacterial microbiota is largely unknown. This study aimed to identify the natural bacterial microbiota of Naegleria fowleri, Acanthamoeba castellanii, Acanthamoeba lenticulata, and Acanthamoeba sp. T17, isolated from untreated (rivers) and treated (tap) waters in Guadeloupe.The whole bacterial microbiota of the water source and the FLA grown with E. coli and under axenic culture conditions, during successive passages, were characterized using 16S rRNA gene metabarcoding. The culturable subset of ARB was identified by mass spectrometry (MALDI-TOF MS) followed by conventional 16S PCR, and bacterial antibiotic resistance was analyzed using the disk diffusion method. Transmission electron microscopy was used to locate ARB within the amoebae. The metabarcoding analyses identified Salmonella, Enterobacter and Klebsiella genera as the most abundant bacteria in untreated and treated waters. However, the most frequently detected amoeba-resistant bacteria (ARB
Confocal fluorescence microscopy reveals subtle lignification variations in a Scots pine blue ring
No full textInternational audienceBlue rings (BRs) are anomalies in tree rings revealed by a double staining technique. They have been thought to reflect reduced cell wall lignification during ephemeral end-of-growing-season cold periods, often following significant volcanic eruptions. BRs have been distinguished visually according to qualitative descriptions and are considered a promising proxy for cold extremes at the intra-seasonal scale. However, reduced cell wall lignin content has never been successfully measured in BRs, limiting understanding of their relationship with thermal (or other) conditions. Further, difference in lignin content between BRs and ‘standard’ rings has not been confirmed independently of the double staining method. Here, using confocal microscopy of samples of Scots pine, we show that BRs are indeed associated with marked reduction of lignin in latewood cells. We also identify subtle variations in lignin across rings that are not well resolved by the double staining method. We draw on these findings to propose a new framework to visualise and measure lignin changes in tree rings. Our findings emphasise the potential of BRs as a paleoproxy of intraseasonal climate variability
Cyclic N, O-acetals and corresponding opened N, N-aminals as new scaffolds with promising anti-inflammatory and antifungal activities against Candida albicans
No full textInternational audienc
Prévalence de l’automédication chez les transplantés rénaux : une étude transversale monocentrique
No full textInternational audienceImportance Vitamin D deficiency is a risk factor for multiple sclerosis (MS) and is associated with the risk of disease activity, but data on the benefits of supplementation are conflicting. Objective To evaluate the efficacy of high-dose cholecalciferol as monotherapy in reducing disease activity in patients with clinically isolated syndrome (CIS) typical for MS. Design, Setting, and Participants The D-Lay MS trial was a parallel, double-blind, randomized placebo-controlled clinical trial in 36 MS centers in France. Patients were enrolled from July 2013 to December 2020 (final follow-up on January 18, 2023). Untreated patients with CIS aged 18 to 55 years with CIS duration less than 90 days, serum vitamin D concentration less than 100 nmol/L, and diagnostic magnetic resonance imaging (MRI) meeting 2010 criteria for dissemination in space or 2 or more lesions and presence of oligoclonal bands were recruited. Intervention Patients were randomized 1:1 to receive oral cholecalciferol 100 000 IU (n = 163) or placebo (n = 153) every 2 weeks for 24 months. Main Outcomes and Measures The primary outcome measure was disease activity, defined as occurrence of a relapse and/or MRI activity (new and/or contrast-enhancing lesions) over 24 months of follow-up, also analyzed as separate secondary outcomes. Results Of the 316 participants enrolled and randomized (median [IQR] age, 34 [28-42] years; 70% women), the primary analysis included 303 patients (95.9%) who took at least 1 dose of the study drug and 288 (91.1%) ultimately completed the 24-month trial. Disease activity was observed in 94 patients (60.3%) in the vitamin D group and 109 patients (74.1%) in the placebo group (hazard ratio [HR], 0.66 [95% CI, 0.50-0.87]; P = .004), and median time to disease activity was longer in the vitamin D group (432 vs 224 days; log-rank P = .003). All 3 secondary MRI outcomes reported significant differences favoring the vitamin D group vs the placebo group: MRI activity (89 patients [57.1%] vs 96 patients [65.3%]; HR, 0.71 [95% CI, 0.53-0.95]; P = .02), new lesions (72 patients [46.2%] vs 87 patients [59.2%]; HR, 0.61 [95% CI, 0.44-0.84]; P = .003), and contrast-enhancing lesions (29 patients [18.6%] vs 50 patients [34.0%]; HR, 0.47 [95% CI, 0.30-0.75]; P = .001). All 10 secondary clinical outcomes showed no significant difference, including relapse, which occurred in 28 patients (17.9%) in the vitamin D group vs 32 (21.8%) in the placebo group (HR, 0.69 [95% CI, 0.42-1.16]; P = .16). Results were similar in a subset of 247 patients meeting updated 2017 diagnostic criteria for relapsing-remitting MS at treatment initiation. Severe adverse events occurred in 17 patients in the vitamin D group and 13 in the placebo group, none of which were related to cholecalciferol. Conclusions and Relevance Oral cholecalciferol 100 000 IU every 2 weeks significantly reduced disease activity in CIS and early relapsing-remitting MS. These results warrant further investigation, including the potential role of pulse high-dose vitamin D as add-on therapy. Trial Registration ClinicalTrials.gov Identifier: NCT0181716