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Dynamics of Temporal and Spatial Transmission of Vaccine-derived Poliovirus (VDPV) in the Democratic Republic of Congo from 2018 to 2023
No full textInternational audienceBackground: Vaccine-derived polioviruses (VDPVs) are rare forms of poliovirus that have evolved genetically from the attenuated virus present in oral polio vaccine (OPV). This process occurs during widespread human-to-human transmission in populations with low immunity, or after prolonged replication in the intestines of immunodeficient individuals following vaccination. The Democratic Republic of Congo (DRC) has been facing outbreaks of VDPV since 2017. These wild poliovirus variants are responsible for poliomyelitis, which is in the process of eradication. The following lines show the evolution of VDPV cases across the country in order to understand their chronological dynamics and seasonal influence.Aim: The study aims to analyze the temporal and spatial dynamics of vaccine-derived poliovirus (VDPV) transmission in the Democratic Republic of Congo from 2018 to 2023.Methods: A cross-sectional study was conducted on VDPV and reported in the DRC from 2018 to 2023. Maps of the spatial dynamics of VDPV cases were produced from attack rates with QGIS® (3.22.8). As for temporal dynamics, time series were decomposed and presented in the form of graphs showing the chronological evolution of VDPV cases and their seasonal trend, using R.4.0 software package.Results: A total of 1196 Cases of VDPV types 1, 2 and 3 were recorded in the biological confirmation databases of the INRB and the Expanded Program of Immunization during the study period across 25 provinces. The eastern part of the country reports the most cases. The general trend is upwards, with a peak in 2022 of 527 cases, whereas in 2021 there was a notable drop of 31 cases. The study of the spatiotemporal dynamics of VDPV cases in the DRC (2018 - 2023) highlights a convincing fact, which is spatial heterogeneity. This would be linked to climatic and environmental factors. Analysis of the temporal breakdown suggests a seasonal pattern, with peaks between the months of September and December, considered to be rainy periods in some provinces. Moreover, in endemic countries and areas, PVS has a seasonal pattern that varies according to geographical region. In tropical or semi-tropical regions, PV circulation tends to be cyclical and is often associated with the rainy season.Conclusion: This study of the temporal and spatial dynamics of VDPV has shown the extent of variant poliovirus epidemics and their heterogeneous distribution in the DRC. During the 6 years of the study (2018 - 2023), almost all the Health Zones were hit by VDPV epidemics. The eastern part was the most impacted. The seasonal component is well marked suggesting a rise in detection in the rainy season and during pivotal periods of climate change. This analysis highlights the contribution of the seasonal component to poliovirus circulation; the variation in relative humidity according to season and health zones can partly explain fluctuations in the number of VDPV cases. This result opens the way to taking into account the seasonal component of PV transmission
Mayotte et protection de l'environnement : droit commun sur terre spéciale ?
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Subduction‐Related Volcanic Activity as a Proxy for Global Subduction Flux Over the Past Billion Years, and Its Correlation With Geomagnetic Superchrons
No full textInternational audienceWe investigate the frequency of subduction‐related volcanic events over the past billion years. Our analysis reveals distinct peaks and troughs interpreted as significant fluctuations in global subduction flux. This approach has the advantage of being independent of paleogeographic reconstructions. However, it does not provide information on the spatial distribution of thermal heterogeneities at the core‐mantle boundary. This likely explains why the long‐term evolution of global subduction flux does not correlate in any simple way with the frequency of geomagnetic polarity reversals throughout the Phanerozoic. As an additional parameter, we suggest focusing on how variations in the Earth's inertia, due to changing subduction configurations over time, influence the thermal conditions at the core‐mantle boundary and, consequently, the magnetic reversal frequency
Characterization of aerosol optical depth (AOD) anomalies in September and October 2022 over Skukuza in South Africa
No full textInternational audienceAbstract. Most major field campaigns, such as the Southern Africa Fire Atmosphere Research Initiative (SAFARI-92 and SAFARI-2000) and AErosol, RadiatiOn and CLOuds in southern Africa (AEROCLO-sA), have focused on the west coast of southern Africa, leaving the east coast underexplored. To address this, the Biomass Burning Aerosol Campaign (BiBAC) was initiated by the IRP ARSAIO (International Research Project – Atmospheric Research in Southern Africa and Indian Ocean) during the 2022 biomass burning season to study aerosol optical properties over southern Africa and the southwestern Indian Ocean (SWIO). This study analyzes aerosol properties during the intensive observation period (IOP) of BiBAC at Skukuza in Kruger National Park during two events: 18–23 September (Event 1) and 9–17 October (Event 2). Sun-photometer data, consistent with CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization), revealed a predominance of biomass burning aerosols. Transport analyses show southeastward movement of carbon monoxide (CO) and aerosols, reaching up to 6 km during Event 1 and 10 km during Event 2. Synoptic conditions, including frontal systems and baroclinic waves, drove regional and intercontinental pollutant transport, impacting the Mozambique Channel and surrounding areas. A “river of smoke” observed in Event 1 suggests novel synoptic conditions compared to previous studies. This study is the first to highlight two distinct transport mechanisms of aerosol plumes and CO from southern Africa and South America toward the SWIO basin, underscoring the significance of east-coast observations in understanding regional and global atmospheric dynamics
Development of the Incompatible Insect Technique targeting Aedes albopictus : introgression of a wild nuclear background restores the performance of males artificially infected with Wolbachia
No full textInternational audienceABSTRACT The bacterium Wolbachia pipientis is increasingly studied for its potential use in controlling insect vectors or pests due to its ability to induce Cytoplasmic Incompatibility (CI). CI can be exploited by establishing an opportunistic Wolbachia infection in a targeted insect species through trans-infection and then releasing the infected males into the environment as sterilizing agents. Several host life history traits (LHT) have been reported to be negatively affected by artificial Wolbachia infection. Wolbachia is often considered the causative agent of these detrimental effects, and the importance of the host’s genetic origins in the outcome of trans-infection is generally overlooked. In this study, we investigated the impact of host genetic background using an Aedes albopictus line recently trans-infected with w Pip from the Culex pipiens mosquito, which exhibited some fitness costs. We measured several LHTs including fecundity, egg hatch rate, and male mating competitiveness in the incompatible line after four rounds of introgression aiming at restoring genetic diversity in the nuclear genome. Our results show that introgression with a wild genetic background restored most fitness traits and conferred mating competitiveness comparable to that of wild males. Finally, we show that introgression leads to faster and stronger population suppression under laboratory conditions. Overall, our data support that the host genome plays a decisive role in determining the fitness of Wolbachia -infected incompatible males. IMPORTANCE The bacterium Wolbachia pipientis is increasingly used to control insect vectors and pests through the Incompatible Insect Technique (IIT) inducing a form of conditional sterility when a Wolbachia -infected male mates with an uninfected or differently infected female. Wolbachia artificial trans-infection has been repeatedly reported to affect mosquitoes LHTs, which may in turn compromise the efficiency of IIT. Using a tiger mosquito ( Aedes albopictus ) line recently trans-infected with a Wolbachia strain from Culex pipiens and displaying reduced fitness, we show that restoring genetic diversity through introgression significantly mitigated the fitness costs associated with Wolbachia trans-infection. This was further demonstrated through experimental population suppression, showing that introgression is required to achieve mosquito population suppression under laboratory conditions. These findings are significant for the implementation of IIT programs, as an increase in female fecundity and male performance improves mass rearing productivity as well as the sterilizing capacity of released males
Les Mahorais à La Réunion : entre apprentissage du français et construction identitaire
No full textInternational audienceLa migration des Mahorais vers La Réunion a engendré des dynamiques linguistiques et culturelles complexes marquées par des enjeux d'exclusion, d'acculturation et de reconfigurations identitaires. Les Mahorais, issus d'un contexte culturel et linguistique spécifique, font face à des défis particuliers liés à l'acquisition du français, langue officielle de la République. Si l'apprentissage de cette langue est souvent perçu comme un vecteur d'intégration sociale et professionnelle, il peut également soulever des questions identitaires complexes, liées à la préservation de leur patrimoine culturel et à la construction d'une identité hybride dans un contexte de plurilinguisme et de diversité culturelle. Dans la présente communication, nous nous intéressons particulièrement à l'impact de l'apprentissage du français sur la construction identitaire des parents mahorais inscrits dans le cadre du dispositif de l’OEPRE (Ouvrir l’école aux parents pour la réussite des élèves) copiloté par le CASNAV et le Département à La Réunion. Quelles sont les perceptions des Mahorais quant à l'impact de la formation linguistique en français sur leur identité, leur intégration sociale et professionnelle ? Quels sont les défis rencontrés lors de l'apprentissage du français au sein dudit dispositif ? Inscrite dans une approche sociodidactique (Blanchet et Chardenet, 2011), notre étude qualitative apporte des éléments de réponses à ces questions en nous reposant sur des entretiens semi-directifs que nous avons menés avec six parents mahorais inscrits dans un atelier OEPRE à l’Est de l’île où se concentre une population mahoraise considérable. L’analyse thématique des données recueillies nous permettra de mettre en avant les perceptions de ces parents de la formation qu’ils suivent et son impact sur leur identité avant de déboucher sur la proposition de quelques perspectives pour une intégration réussie et durable des Mahorais au sein de la société réunionnaise
Evaluation of Hygiene Practices among Medical Staff Using Mobile Phones at Yaoundé General Hospital: Implications for Infection and Sepsis Prevention
No full textInternational audienceBackground: Nosocomial infections, particularly sepsis, represent a major public health challenge, especially in hospital settings where hygiene practices may fall short. The use of mobile phones by medical staff can act as a vector for pathogen transmission, thereby increasing the risk of cross-infections. This study aims to evaluate the hygiene practices of medical staff when using mobile phones at Yaoundé General Hospital and assess their impact on infection and sepsis prevention. Materials and methods: A cross-sectional, analytical, and evaluative study was conducted among medical staff within the hospital. Utilising a stratified random sampling method, this study included 162 participants. Data were collected through direct observations, structured questionnaires, semi-structured interviews, and microbiological analyses of samples taken from mobile phones and hospital surfaces. Statistical analyses comprised both descriptive and comparative tests. Results: The findings revealed that 97.5% of medical staff carry their phones at work, 85.8% use them in clinical settings, and 60.5% do not wash their hands after answering calls. Microbiological analysis detected potentially pathogenic bacteria, including Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli, on mobile phones. Disinfection practices were inconsistent and frequently inadequate, with only 45.7% of participants using an alcohol-based disinfectant. Conclusion: This study highlights the urgent need for heightened awareness and the establishment of stringent disinfection protocols for mobile phones within hospital settings to mitigate the transmission of nosocomial infections and sepsis. Implementing specific recommendations, such as training sessions and hygiene audits, is essential to enhance the hygiene practices of medical staff
Activity of low-mass stars in the light of spot signature in the Fourier domain
No full textInternational audienceContext. Magnetic fields exhibit a wide variety of behaviours in low-mass stars and further characterisation is required to understand these observations. Stellar photometry from space missions such as MOST, CoRoT, Kepler, and TESS (and in the near future PLATO) provide thousands of highly precise light curves (LCs) that can shed new light on stellar activity, in particular through the signature of transiting spots.Aims. We study the impact of star spots on LCs in the Fourier domain, reducing the degeneracies encountered by direct spot modelling in the temporal domain. We use this new formulation to explore the spot properties from the available data.Methods. We propose a model of LC power spectra at low frequency based on a description of spot transits that allows us to retrieve information about the amplitude of their photometric impact ℋ and about the spot mean lifetime over the observation τlife when the power spectrum exibits rotation peaks. We validated this method with simulated LCs and then applied it to the Kepler data to extract global trends over a set of more than 37 755 stars.Results. Our analysis leads to a classification of the sample into ‘peakless’ or ‘with peaks’ spectra and enables the identification of different activity regimes based on ℋ and τlife for different Rossby number ranges. More specifically, we observed an intense regime of activity between Ro = 0.7 and Ro = 1, for stars with masses under 1 M⊙.Conclusions. This new systematic method can be used to provide new observational constraints on stellar activity (and possibly a link with stellar magnetism) when applied to large photometric datasets, such as those from the future PLATO mission
Passé, Présent et Avenir à Mayotte : contribution à l’étude des temporalités en contexte pluriculturel
No full textInternational audience« Mayotte entre passé, présent et avenir » est le titre donné à ce colloque qui interroge d’emblée la linéarité a priori du temps et des temporalités dans le contexte territorial Mahorais. Le territoire de Mayotte fait se rencontrer des systèmes de connaissances culturelles des mondes de façon intriquée (Lambek, 2018), entre islam, cultures africaines, malgaches, françaises et arabes, ce qui participe parfois de certaines sources de confusion, voire de crispation, quant à la définition d’un objet partagé comme le temps. Au travers d’une recherche théorique sur le concept de temps prenant appui sur divers auteurs tels que Kosseleck (1990), Hartog (2003, 2020, 2022), ou encore Chesneaux (1996), en passant par le concept antique de Chronos, nous proposons un modèle à vocation heuristique, baptisé « chronoglyphe » que nous mobilisons pour l’analyse des temporalités selon une approche contrastive (Yllera, 2001) en contexte pluriculturel. Après avoir présenté notre modèle, nous en proposerons une mise en application dans le contexte mahorais, au travers du concept d’umri tel que décrit par Blanchy (1988), et nous proposerons une discussion sur les conséquences contemporaines de cette conception temporelle