Histoire évolutive de la maladie carieuse : exemple des populations inuites

La maladie carieuse est une pathologie considérée comme le troisième fléau mondial par l’Organisation Mondiale de la Santé, puisqu’elle touche plus de 99 % des adultes. Historiquement, en Europe, la prévalence carieuse augmente progressivement depuis le Néolithique jusqu’à atteindre un pic au XXe siècle et ne commence à diminuer que depuis les 25 dernières années. Cependant, cette maladie n’a pas connu la même histoire évolutive dans toutes les populations humaines. Dans le cadre d’une thèse,..

Histoire démographique des ancêtres de la population malgache actuelle à partir des données génétiques

Bien que situé à 400 km de l’Afrique, les habitants de Mada­gascar partagent des caractéristiques linguistiques, culturelles et génétiques avec des populations d’Indonésie et de la côte Est d’Afrique. Il a été montré que la population malgache est issue d’un mélange entre des populations bantu et austronésienne pendant le dernier millenium. Néanmoins, l’histoire du peuplement de l’île par les ancêtres de la population malgache actuelle reste encore incomplet et confus. Ici, nous cherchons à e..

Contribution de l’anthropologie sensorielle à l’étude du COVID-19

En réponse à la pandémie COVID-19, de nombreux gouvernements ont pris des mesures sans précédent pour éviter un engorgement des unités de réanimation. En raison du lourd impact sociétal et économique de ces initiatives, des indicateurs épidémiologiques précis de la propagation de la maladie sont essentiels aux autorités de santé publique. Dans le même temps, la perturbation des perceptions des odeurs et du goût ont été identifiés comme l’un des symptômes les plus spécifiques de la maladie COV..

Studying Chemosensory Perception and Its Hedonic Component in an Anthropological Context: From Genetics to Psychophysical Measures

International audienc

Studying Chemosensory Perception and Its Hedonic Component in an Anthropological Context: From Genetics to Psychophysical Measures

International audienc

Development of a Multiple-Locus Variable-Number Tandem-Repeat Typing Scheme for Genetic Fingerprinting of Burkholderia cenocepacia and Application to Nationwide Epidemiological Analysis

International audienceOrganisms of the Burkholderia cepacia complex are especially important pathogens in cystic fibrosis (CF), with a propensity for patient-to-patient spread and long-term respiratory colonization. B. cenocepacia and Burkholderia multivorans account for the majority of infections in CF, and major epidemic clones have been recognized throughout the world. The aim of the present study was to develop and evaluate a multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) scheme for B. cenoce-pacia. Potential VNTR loci were identified upon analysis of the annotated genome sequences of B. cenocepacia strains AU1054, J2315, and MCO-3, and 10 of them were selected on the basis of polymorphisms and size. A collection of 100 B. cenocepacia strains, including epidemiologically related and unrelated strains, as well as representatives of the major epidemic lineages, was used to evaluate typeability, epidemiological concordance, and the discriminatory power of MLVA-10 compared with those of pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Longitudinal stability was assessed by testing 39 successive isolates from 14 patients. Typeability ranged from 0.91 to 1, except for that of one marker, which was not amplified in 53% of the B. cenocepacia IIIA strains. The MLVA types were shown to be stable in chronically colonized patients and within outbreak-related strains, with excellent epidemiological concordance. Epidemic and/or globally distributed lineages (epidemic Edinburgh-Toronto electrophoretic type 12 [ET-12], sequence type 32 [ST-32], ST-122, ST-234, and ST-241) were successfully identified. Conversely, the discriminatory power of MLVA was lower than that of PFGE or MLST, although PFGE variations within the epidemic lineages sometimes masked their genetic relatedness. In conclusion, MLVA represents a promising cost-effective first-line tool in B. cenocepacia surveillance

The autumnal lockdown was not the main initiator of the decrease in SARS-CoV-2 circulation in France

International audienceBackground In response to the SARS-CoV-2 pandemic, governments have taken drastically restrictive public health measures with significant collateral effects. It is important to understand the impact of these measures on SARS-CoV-2 circulation. However, pandemic indicators lag behind the actual level of viral circulation and these delays are an obstacle to assessing the effectiveness of policy decisions. Here, we propose one way to solve this problem by synchronizing the indicators with viral circulation in a country (France) based on a landmark event.Methods Based on a first lockdown, we measured the time lag between the peak of gov- ernmental and non-governmental surveillance indicators and the highest level of virus cir- culation. This allowed alignment of all surveillance indicators with viral circulation during the second period of the epidemic, overlaid with the type of public health measures implemented. Results We show that the second peak in viral circulation in France happened ~21 October 2020, during the public health state of emergency but before the lockdown (31 October). Indicators also suggest that viral circulation decreased earlier in locations where curfews were implemented. Indicators did, however, begin to rise once the autumnal lockdown was lifted and the state of emergency resumed.Conclusions Overall, these results suggest that in France, the 2020 autumnal lockdown was not the main initiator of the decrease in SARS-CoV-2 circulation and curfews were important in achieving control of the transmission. Less-restrictive measures may need to be balanced with more-stringent measures to achieve desirable public health outcomes over time

Homo icarus : Evolution biologique de l'homme dans l'espace

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Oral health status in historic population: Macroscopic and metagenomic evidence

International audienceRecent developments in High-Throughput DNA sequencing (HTS) technologies and ancient DNA (aDNA) research have opened access to the characterization of the microbial communities within past populations. Most studies have, however, relied on the analysis of dental calculus as one particular material type particularly prone to the molecular preservation of ancient microbial biofilms and potential of entire teeth for microbial characterization, both of healthy communities and pathogens in ancient individuals, remains overlooked. In this study, we used shotgun sequencing to characterize the bacterial composition from historical subjects showing macroscopic evidence of oral pathologies. We first carried out a macro-scopic analysis aimed at identifying carious or periodontal diseases in subjects belonging to a French rural population of the 18th century AD. We next examined radiographically six subjects showing specific, characteristic dental pathologies and applied HTS shotgun sequencing to characterize the microbial communities present in and on the dental material. The presence of Streptococcus mutans and also Rothia dentocariosa, Actinomyces visco-sus, Porphyromonas gingivalis, Tannerella forsythia, Pseudoramibacter alactolyticus, Olse-nella uli and Parvimonas micra was confirmed through the presence of typical signatures of post-mortem DNA damage at an average depth-of-coverage ranging from 0.5 to 7X, with a minimum of 35% (from 35 to 93%) of the positions in the genome covered at least once. Each sampled tooth showed a specific bacterial signature associated with carious or peri-odontal pathologies. This work demonstrates that from a healthy independent tooth, without visible macroscopic pathology, we can identify a signature of specific pathogens and deduce the oral health status of an individual