Correlation between some environmental variables and abundance of Almophrya mediovacuolata (Ciliophora: Anoplophryidae) endocommensal ciliate of an anecic earthworms (Oligochaeta: Annelida) in Bambui (North-West Cameroon)

This study was devoted to accessing the influence of some soil physico-chemical parameters on the abundance of Almophrya mediovacuolata Ngassam, 1983, astome ciliate of the digestive tract of earthworms (EW) of the species Alma nilotica collected along “Fa’a ntsa” stream in Bambui. The survey primarily involved soil samples collection from the same spots of EW collection and preparation for physico-chemical analysis; evaluation in situ of the volumic density (VD) of worms (number /dm3 soil), their dissection, isolation and counting of ciliates with respect to different portion of EW’s gut (fore, mid and hindgut). Furthermore, correlation analysis between soil physico-chemical parameters and biological responses (EW volumic density and ciliate abundance) were performed. The results reveal that EW abundance was positively and significantly correlated with the following physico-chemical parameters: Cation Exchange Capacity CEC (p <0.01) and Mg2+ (p <0.05). A positive and significant correlation was found between Almophrya mediovacuolata and the pH of KCl in the foregut and midgut (p <0.01) while a negative and significant correlation was found between the abundance of Almophrya mediovacuolata and Ca2+ in the foregut (p <0.05). Almophrya mediovacuolata were found mostly in the foregut. This result shows that each portion of the digestive tract of Alma nilotica can be considered as a set of natural microhabitat in which a number of physico-chemical factors generate ecological niches suitable for the survival of different species of microorganisms among which ciliated protozoa. The fore and midgut was noticed to be the preferential zones of Almophrya mediovacuolata.Keywords: Biotic parameters, ciliated protozoa, microhabitat, soil physico-chemical parameters

The All-Data-Based Evolutionary Hypothesis of Ciliated Protists with a Revised Classification of the Phylum Ciliophora (Eukaryota, Alveolata)

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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

Révision de la sous-famille des Metaracoelophryinae de Puytorac 1972 (Oligohymenophora : Hoplytophryida : Hoplytophryidae), ciliés astomes du tube digestif d’oligochètes terricoles d’Afrique : description de cinq espèces nouvelles

Cinq nouvelles espèces de ciliés astomes, présentes dans le tube digestif de vers oligochètes du genre Alma du Cameroun, ont été décrites. Les techniques utilisées sont : l’observation vitale, la coloration au DAPI, la microscopie électronique à balayage et les imprégnations argentiques selon Fernandez Galiano, 1966. Ce travail confirme la présence des genres Paracoelophrya et Dicoelophrya dans le tube digestif des oligochètes du genre Alma du Gabon et du Cameroun ; il permet de faire une synthèse récapitulative de la sous-famille des Metaracoelophryinae. De plus, est confirmée l’homogénéité de ce groupe, et est reposée la question de la parenté phylogénétique des Hoplitophryida

Révision de la sous-famille des Metaracoelophryinae de Puytorac 1972 (Oligohymenophora : Hoplytophryida : Hoplytophryidae), ciliés astomes du tube digestif d’oligochètes terricoles d’Afrique : description de cinq espèces nouvelles

Cinq nouvelles espèces de ciliés astomes, présentes dans le tube digestif de vers oligochètes du genre Alma du Cameroun, ont été décrites. Les techniques utilisées sont : l’observation vitale, la coloration au DAPI, la microscopie électronique à balayage et les imprégnations argentiques selon Fernandez Galiano, 1966. Ce travail confirme la présence des genres Paracoelophrya et Dicoelophrya dans le tube digestif des oligochètes du genre Alma du Gabon et du Cameroun ; il permet de faire une synthèse récapitulative de la sous-famille des Metaracoelophryinae. De plus, est confirmée l’homogénéité de ce groupe, et est reposée la question de la parenté phylogénétique des Hoplitophryida

Morphological characterization of two new species of Dicontophrya (Ciliophora: Astomatia: Contophryidae) commensal of earthworms (Oligochaeta: Annelida) of Ebebda and Nkolbikogo (Cameroon)

International audienceTwo new species of astomatous ciliates (Dicontophrya minus n. sp. and Dicontophrya ebebdaensis n. sp.) endocommensal of Glossoscolecidae earthworms pertaining to the genus Alma are described using light-microscopy and a combination of staining techniques (pyridinated ammoniacal silver nitrate and DAPI). Studies reveal the existence of two distinct morphological types as evidence of morphological diversification within the genus Dicontophrya de Puytorac and Dragesco, 1969. In the first morphological type represented by Dicontophrya minus n. sp., the cell is ovoid (90×125-35×115 µm) with a ribbon like axial macronucleus flanked with a relatively big micronucleus (6.2 µm in diameter). In the second morphological type (Dicontophrya ebebdaensis n. sp.), the cell is elongated and wormlike (180×215-35×50 µm) with a nuclear apparatus composed of a long ribbon shape macronucleus (171.1 µm), bearing in its posterior half a globulous micronucleus. In the two cases cells bear in the anterior end a depression in which lodges a skeletal apparatus build in the same plan of organization (a modified V shaped skeletal branch bearing about 7 skeletal fibers) that characterize the genus

Soil physicochemical parameters affecting abundance and distribution of Dicoelophrya nkoldaensis (ciliophora : radiophryidae) living in the gut of earthworms (Annelida : glossoscolecidae) collected in Bambui (nord-west Cameroon)

International audienc

Viruses and bacteria microfauna of the soil and the digestive tract of earthworms (Oligochaetes annelids) of Cameroon: highlighting, quantification and importance

International audienceThe flow cytometry technique, based on the enumeration and multi -parametric analysis of suspended particles in a liquid medium, has enabled us to identify an population of viruses and bacteria in the soil and the digestive tract of earthworms. It appears that the p assage of the ground through the digestive tract of oligochaetes annelids would regulate bacterial and viral biomass of the soil as well as soil physico-chemical parameters. The soil microfauna is involved in the decomposition of the organic material and the nutrient bioavailability to plants and soil microorganisms. It also plays an important role in the creation and conservation of the soil structure. Apart fr om their role as "engineers", earthworms through their internal microfauna, participate in the regulation of physical and chemical parameters such as nitrogen mineralization. Earthworms thus participate in the processes of decomposition of organic material improve the bioavailability of minerals, maintain the porosity of the soil and increase the stability of the aggregates. Oligochaetes are expected to play a central role in the implementation of biological regulation in the agro-ecosystems essential to the development of ecological and intensive agriculture. Another reason to be interested in these soil organisms is that they are good candidates for bio-indicators. Indeed, the level of their population is sensitive to cultural practices, chemical products that are spread, quality and quantity of the resource in carbon, which are important characteristics of the sustainability of agricultural systems

Stroke in sickle cell anemia: New concepts in diagnosis and management

Stroke is a devastating and potentially fatal complication of sickle cell disease. The highest incidence of cerebrovascular disease is in the first 10 years and especially between 2 to 5 years. Two types of stroke occur in these patients – infarctive and hemorrhagic strokes. While infarctive strokes occur frequently in children, hemorrhagic strokes occur mostly in adults. Associated risk factors include: history of transient ischemic attacks, association of acute chest syndrome, severe anemia, a high leukocyte count and a genetic susceptibility. In the presence of stroke, the main investigations are computed tomography and magnetic resonance imaging. Primary prevention is the main axis of management. This consists of transcranial Doppler ultrasonography screening in sicklers as from 2 years of age every 6 months, and patients with abnormal velocities of or greater than 200cm/seconds should receive chronic transfusion therapy every 3 – 4 weeks. The decision to initiate transfusion should be based on careful consideration of the risks and benefits. This with the aim of averting the inherent motor and neuropsychogical impairments from stroke.L'accident vasculaire cérébral (AVC) chez le drépanocytaire est une complication grave greffée d'une mortalité élevée.L'incidence la plus élevée est dans la première décennie de la vie surtout entre 2 et 5 ans. Il existe deux types d'AVC chez le drépanocytaire – ischémique et hémorragique. Les accidents ischémiques surviennent surtout chez les enfants, et les accidents hémorragiques surtout chez les adultes. Les facteurs prédisposants sont : l'antécédent d'accident ischémique transitoire, le syndrome thoracique aiguë, l'anémie sévère, la leucocytose et une susceptibilité génétique. En présence d'AVC, les principaux examens sont : le scanner cérébral, et l'imagerie par résonance magnétique. La prévention primaire reste le principal axe du traitement. Ceci consiste à pratiquer un Doppler transcrânien chez les drépanocytaires dès l'âge de 2 ans et tous les 6 mois et les patients ayant des vitesses moyennes des artères du polygone de Willis supérieur ou égale à 200 cm/seconde bénéficieront d'un programme de transfusion périodique toutes les 3-4 semaines. La décision d'initier la transfusion ne doit être prise qu'après avoir évalué les risques et bénéfices des transfusions. Cette prise en charge permet de prévenir les séquelles motrices et neuropsychiques liées à cette affection. Keywords: Stroke - Sickle cell anemia - Risk factors - Clinical presentation - Diagnosis - Management Clinics in Mother and Child Health Vol. 3(2) 2006: pp. 585-59

Variations morphologiques de l’appareil nucléaire chez les ciliés Astomes Almophrya bivacuolata et A. mediovacuolata (Protozoa : Ciliophora) endocommensaux d’oligochètes terricoles du Cameroun

L’imprégnation argentique complétée par la coloration nucléaire de Feulgen et la coloration au DAPI nous ont permis d’étudier les variations morphologiques de l’appareil nucléaire chez deux espèces de ciliés Astomes, Almophrya bivacuolata (de Puytorac et Dragesco, 1968) et A. mediovacuolata (Ngassam, 1983) endocommensaux. Nous avons mis en évidence d’importantes digitations et la présence de bandes sombres dans la structure du macronoyau en “H” des petits types cellulaires ainsi que la présence de formes intermédiaires entre “H” et “X” dans ces deux espèces