Caractérisation de la Dynamique des Peuplements Ligneux du Centre Nationale de Recherches Agronomiques de Bambey (Diourbel/Sénégal)

Le Sénégal, à l’instar des autres pays sahéliens, est confronté à la dégradation de ses espaces forestiers due à un ensemble de facteurs tels que : les défrichements agricoles, les feux tardifs, l’exploitation anarchique, etc. Ce phénomène est plus accentué dans la région de Diourbel où l’un des très rares poumons verts se trouve dans le site du Centre National de Recherches Agronomiques de Bambey (CNRA). Cette étude avait comme objectifs de caractériser et d’estimer le potentiel des ligneux dans cette formation forestière dans le but de donner formuler des recommandations. Un inventaire systématique sur 103 placettes de 50 X 50 m a été réalisé en 2018. Les paramètres recherchés ont été : la richesse spécifique, la densité du peuplement, la surface terrière, le volume de bois, le couvert aérien, la régénération, la structure horizontale et verticale, les observations sur l’émondage, le vieillissement, etc. Ainsi, 28 espèces appartenants à 13 familles ont été recensées. Les familles des Mimosaceae (28,57%) et des Combretaceae (17,86%) dominent la végétation. Pour les individus adultes, la densité est de 98 individus/ha, dominée par Acacia seyal, tandis que la régénération s’élève à 581 plantules/ha, dominée par Combretum aculeatum. La surface terrière du peuplement est estimée à 2,12 m2/ha, le couvert aérien (3223,08 m2/ha) et le volume (13,83 m3/ha). La distribution du peuplement par classe de diamètre et de hauteur révèle la prédominance de la strate arbustive. Les observations ont montré la présence de pratiques anthropiques qui pourraient contribuer à la régression de la dynamique du peuplement par la diminution du couvert végétal et la disparition de certaines espèces (Deterium microcarpum, Pterocarpus erinaceus et Sterculia setigera) constatée dans cette formation.  Ces résultats montrent l’urgence de mettre en place une stratégie de gestion en étroite collaboration avec les communautés pour la conservation et la restauration du couvert végétale de cette formation boisée de 149 ha.   Senegal, like other Sahelian countries, is faced with the degradation of its forest areas due to a combination of factors such as agricultural clearing, late fires, uncontrolled logging, etc. This phenomenon is more pronounced in the Diourbel region, where one of the very few green lungs is located on the site of the Centre National de Recherches Agronomiques Bambey (CNRA). This phenomenon is more pronounced in the Diourbel region, where one of the very few green lungs can be found on the site of the “Centre National de Recherches Agronomiques de Bambey” (CNRA). The objectives of this study were to characterize and estimate the potential of woody species in this forest formation, to formulate recommendations. A systematic inventory of 103 50 x 50 m plots was carried out in 2018. The parameters investigated were: species richness, stand density, basal area, wood volume, aerial cover, regeneration, horizontal and vertical structure, observations on pruning, aging, etc. A total of 28 species belonging to 13 families were inventoried. Among these families, Mimosaceae (28,57%) and Combretaceae (17,86%) dominate the vegetation. The density of adult trees is 98 individuals/ha, dominated by Acacia seyal, while regeneration amounts to 581 seedlings/ha, dominated by Combretum aculeatum. The basal area of the stand is estimated at 2.12 m2/ha, the aerial cover (3223.08 m2/ha), and the volume (13.83 m3/ha). The distribution of the stand-by diameter and height class reveals the predominance of the shrub layer. Observations revealed the presence of human practices that could be contributing to the decline in stand dynamics through the reduction in plant cover and the disappearance of certain species (Deterium microcarpum, Pterocarpus erinaceus, and Sterculia setigera) observed in this formation. These results show the urgent need to implement a management strategy in close collaboration with the communities to conserve and restore the plant cover of this 149 ha woodland formation

Caractérisation et Evolution du Peuplement Ligneux du Bois de Boulogne du Centre Nationale de Recherches Agronomiques (CNRA) de Bambey (Diourbel/Sénégal)

Le Sénégal à l’instar des autres pays sahéliens, est confronté à la dégradation de ses espaces forestiers dû à un ensemble de facteurs tels que : les défrichements agricoles, les feux tardifs, l’exploitation anarchique, etc. Des travaux d’inventaires ont été réalisés dans la formation boisée (Bois de Boulogne) du Centre National de Recherches Agronomiques de Bambey. L’étude vise à évaluer le potentiel ligneux du Bois soumis à forte pression anthropique dans le but de donner des recommandations. Un inventaire systématique sur 103 placettes de 50 X 50 m est réalisé en 2018. Les paramètres recherchés sont : la richesse spécifique, la densité, la surface terrière, le volume, le couvert aérien, la régénération, la structure horizontale et verticale, les observations sur l’émondage, le vieillissement, etc. Ainsi, 28 espèces de 13 familles ont été recensées. Mimosaceae et Combretaceae domine la végétation. Pour les individus adultes, la densité est de 98 individus/ha, dominée par Acacia seyal, tandis que la régénération s’élève à 581 plantules/ha, dominée par Combretum aculeatum. La surface terrière du peuplement est estimée à 2,12 m2/ha, le couvert aérien (3223,08 m2/ha) et le volume (13,83 m3/ha). La distribution du peuplement par classe de diamètre et de hauteur révèle la prédominance de la strate arbustive. Les observations ont montré la présence de pratiques anthropiques. Cette étude a permis de recenser la flore du Bois, d’évaluer le potentiel ligneux et de remarquer l’anthropisation, d’où la nécessité de mettre en place une stratégie de gestion pour la conservation et la restauration du couvert végétale.   Senegal, like other Sahelian countries, is faced forest degradation due to a combination of factors such as: agricultural clearings, late fires, uncontrolled logging, etc. Inventory work has been carried out in the woodland formation (Bois de Boulogne) of the Centre National de Recherches Agronomiques de Bambey. The aim of the study was to assess the woody potential of the Bois, which is under heavy human pressure, with a view to making recommendations. A systematic inventory on 103 plots of 50 X 50 m is carried out in 2018. The parameters sought are: species richness, density, basal area, volume, aerial cover, regeneration, horizontal and vertical structure, observations on pruning, ageing, etc. A total of 28 species from 13 families were recorded. Mimosaceae and Combretaceae dominate the vegetation. Adult density is 98 individuals/ha, dominated by Acacia seyal, while regeneration is 581 seedlings/ha, dominated by Combretum aculeatum. Stand basal area is estimated at 2.12 m2/ha, aerial cover (3223.08 m2/ha) and volume (13.83 m3/ha). Stand distribution by diameter and height class reveals the predominance of the shrub layer. Observations revealed the presence of anthropogenic practices. This study enabled us to survey the flora of the wood, assess its woody potential and note its anthropization, hence the need to implement a management strategy for the conservation and restoration of the plant cover

Caractérisation et Evolution du Peuplement Ligneux du Bois de Boulogne du Centre Nationale de Recherches Agronomiques (CNRA) de Bambey (Diourbel/Sénégal)

Le Sénégal à l’instar des autres pays sahéliens, est confronté à la dégradation de ses espaces forestiers dû à un ensemble de facteurs tels que : les défrichements agricoles, les feux tardifs, l’exploitation anarchique, etc. Des travaux d’inventaires ont été réalisés dans la formation boisée (Bois de Boulogne) du Centre National de Recherches Agronomiques de Bambey. L’étude vise à évaluer le potentiel ligneux du Bois soumis à forte pression anthropique dans le but de donner des recommandations. Un inventaire systématique sur 103 placettes de 50 X 50 m est réalisé en 2018. Les paramètres recherchés sont : la richesse spécifique, la densité, la surface terrière, le volume, le couvert aérien, la régénération, la structure horizontale et verticale, les observations sur l’émondage, le vieillissement, etc. Ainsi, 28 espèces de 13 familles ont été recensées. Mimosaceae et Combretaceae domine la végétation. Pour les individus adultes, la densité est de 98 individus/ha, dominée par Acacia seyal, tandis que la régénération s’élève à 581 plantules/ha, dominée par Combretum aculeatum. La surface terrière du peuplement est estimée à 2,12 m2/ha, le couvert aérien (3223,08 m2/ha) et le volume (13,83 m3/ha). La distribution du peuplement par classe de diamètre et de hauteur révèle la prédominance de la strate arbustive. Les observations ont montré la présence de pratiques anthropiques. Cette étude a permis de recenser la flore du Bois, d’évaluer le potentiel ligneux et de remarquer l’anthropisation, d’où la nécessité de mettre en place une stratégie de gestion pour la conservation et la restauration du couvert végétale.   Senegal, like other Sahelian countries, is faced forest degradation due to a combination of factors such as: agricultural clearings, late fires, uncontrolled logging, etc. Inventory work has been carried out in the woodland formation (Bois de Boulogne) of the Centre National de Recherches Agronomiques de Bambey. The aim of the study was to assess the woody potential of the Bois, which is under heavy human pressure, with a view to making recommendations. A systematic inventory on 103 plots of 50 X 50 m is carried out in 2018. The parameters sought are: species richness, density, basal area, volume, aerial cover, regeneration, horizontal and vertical structure, observations on pruning, ageing, etc. A total of 28 species from 13 families were recorded. Mimosaceae and Combretaceae dominate the vegetation. Adult density is 98 individuals/ha, dominated by Acacia seyal, while regeneration is 581 seedlings/ha, dominated by Combretum aculeatum. Stand basal area is estimated at 2.12 m2/ha, aerial cover (3223.08 m2/ha) and volume (13.83 m3/ha). Stand distribution by diameter and height class reveals the predominance of the shrub layer. Observations revealed the presence of anthropogenic practices. This study enabled us to survey the flora of the wood, assess its woody potential and note its anthropization, hence the need to implement a management strategy for the conservation and restoration of the plant cover

Prevalence of Mutations in the \u3ci\u3ePfdhfr\u3c/i\u3e, \u3ci\u3ePfdhps\u3c/i\u3e, and \u3ci\u3ePfmdr1\u3c/i\u3e Genes of Malarial Parasites Isolated from Symptomatic Patients in Dogondoutchi, Niger

The effectiveness of artemisinin-based combination therapies (ACTs) depends not only on that of artemisinin but also on that of partner molecules. This study aims to evaluate the prevalence of mutations in the Pfdhfr, Pfdhps, and Pfmdr1 genes from isolates collected during a clinical study. Plasmodium genomic DNA samples extracted from symptomatic malaria patients from Dogondoutchi, Niger, were sequenced by the Sanger method to determine mutations in the Pfdhfr (codons 51, 59, 108, and 164), Pfdhps (codons 436, 437, 540, 581, and 613), and Pfmdr1 (codons 86, 184, 1034, and 1246) genes. One hundred fifty-five (155) pre-treatment samples were sequenced for the Pfdhfr, Pfdhps, and Pfmdr1 genes. A high prevalence of mutations in the Pfdhfr gene was observed at the level of the N51I (84.97%), C59R (92.62%), and S108N (97.39%) codons. The key K540E mutation in the Pfdhps gene was not observed. Only one isolate was found to harbor a mutation at codon I431V. The most common mutation on the Pfmdr1 gene was Y184F in 71.43% of the mutations found, followed by N86Y in 10.20%. The triple-mutant haplotype N51I/C59R/S108N (IRN) was detected in 97% of the samples. Single-mutant (ICS and NCN) and double-mutant (IRS, NRN, and ICN) haplotypes were prevalent at 97% and 95%, respectively. Double-mutant haplotypes of the Pfdhps (581 and 613) and Pfmdr (86 and 184) were found in 3% and 25.45% of the isolates studied, respectively. The study focused on the molecular analysis of the sequencing of the Pfdhfr, Pfdhps, and Pfmdr1 genes. Although a high prevalence of mutations in the Pfdhfr gene have been observed, there is a lack of sulfadoxine pyrimethamine resistance. There is a high prevalence of mutation in the Pfmdr184 codon associated with resistance to amodiaquine. These data will be used by Niger’s National Malaria Control Program to better monitor the resistance of Plasmodium to partner molecules in artemisinin-based combination therapies

Comparison of molecular quantification of Plasmodium falciparum gametocytes by Pfs25 qRT-PCR and QT-NASBA in relation to mosquito infectivity.

BACKGROUND: Quantifying gametocyte densities in natural malaria infections is important to estimate malaria transmission potential. Two molecular methods (Pfs25 mRNA quantitative reverse transcriptase PCR (qRT-PCR) and Pfs25 mRNA quantitative nucleic acid sequence based amplification (QT-NASBA)) are commonly used to determine gametocyte densities in clinical and epidemiological studies and allow gametocyte detection at densities below the microscopic threshold for detection. Here, reproducibility of these measurements and the association between estimated gametocyte densities and mosquito infection rates were compared. METHODS: To quantify intra- and inter-assay variation of QT-NASBA and qRT-PCR, a series of experiments was performed using culture-derived mature Plasmodium falciparum gametocytes from three different parasite isolates (NF54, NF135, NF166). Pfs25 mRNA levels were also determined in samples from clinical trials in Mali and Burkina Faso using both methods. Agreement between the two methods and association with mosquito infection rates in membrane feeding assays were assessed. RESULTS: Intra- and inter-assay variability was larger in QT-NASBA compared to qRT-PCR, particularly at low gametocyte densities (100 gametocyte per ?L). Samples collected in one of the two transmission studies had extremely low gametocyte densities by both molecular methods, which is suggestive of RNA degradation due to an unknown number of freeze-thaw cycles and illustrates the reliance of molecular gametocyte diagnostics on a reliable cold-chain. CONCLUSIONS: The experiments indicate that both qRT-PCR and QT-NASBA are of value for quantifying mature gametocytes in samples collected in field studies. For both assays, estimated gametocyte densities correlated well with mosquito infection rates. QT-NASBA is less reproducible than qRT-PCR, particularly for low gametocyte densities

Promotion of cardiovascular health in Africa: the Alliance for Medical Research in Africa (AMedRA) expert panel

This proposed scientific statement is focused on providing new insights regarding challenges and opportunities for cardiovascular health (CVH) promotion in Africa. The statement includes an overview of the current state of CVH in Africa, with a particular interest in the cardiometabolic risk factors and their evaluation through metrics. The statement also explains the main principles of primordial prevention, its relevance in reducing noncommunicable disease and the different strategies that have been effective worldwide. Also, the statement addresses challenges for implementing primordial prevention strategies in Africa, such as socioeconomic, cultural, lifestyle, and environmental factors, and highlights the importance of adapting strategies to the context. Finally, the statement recommends fundamental approaches for promoting CVH with the help of various partnerships and the involvement of communities

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century