Ebola and Marburg viruses IgG detections in small ruminants and dogs from villages within outbreak areas in Gabon.

The Ebola virus (EBOV) and Marburg virus (MARV) have been in circulation in Africa for several decades and are the cause of numerous outbreaks. There has been very little research on the role of domestic animals in their transmission to humans, but studies have only been conducted in dogs and pigs where relatively high levels of IgG was detected. These levels suggest that ruminants, which have not been studied, should also be investigated.

Prevalence of post-pandemic SARS-CoV-2 in patients with respiratory syndrome in Brazzaville, Republic of the Congo.

The first confirmed case of COVID-19 was detected in the Republic of the Congo in March 2020. Several control measures were implemented during the pandemic period. As a result, the number of reported cases decreased significantly, leading to the gradual lifting of barrier measures and the declaration of the end of the outbreak on 14 October 2022.

Synthesis and physico-chemical investigation of thiolated dextran derivative: Design and application of a redox-responsive drug delivery system.

In the present investigation, redox-responsive-based dextran carriers were developed for the controlled release of hydrophobic molecules via a reducing agent naturally present in cells, namely glutathione. In this sense, dextran was modified with a thiol derivative. The roles of the hydrophilic segments in the molecular self-organisation of polysaccharide derivatives into nanoparticles were investigated by varying the average dextran molar mass.

Toxoplasma gondii from Gabonese forest, Central Africa: First report of an African wild strain.

The protozoan Toxoplasma gondii is a ubiquitous and highly prevalent parasite that can theoretically infect all warm-blooded vertebrates. In humans, toxoplasmosis causes infections in both immunodeficient and immunocompetent patients, congenital toxoplasmosis, and ocular lesions. These manifestations have different degrees of severity.

A Large-Scale Serological Survey in Pets From October 2020 Through June 2021 in France Shows Significantly Higher Exposure to SARS-CoV-2 in Cats Compared to Dogs.

Introduction: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has the potential to infect various animals, including domestic pets like dogs and cats. Many studies have documented infection in companion animals by molecular and serological methods. However, only a few have compared seroprevalence in cats and dogs from the general population, and these studies were limited by small sample sizes and collections over short periods.

Serological evidence of natural exposure to rabies in rural populations in Gabon.

Rabies is one of the oldest known zoonotic diseases, with dogs being the main reservoir for 99% of the cases of human rabies. However, wild animals may also be rabies vectors. In most cases, contact with a rabid animal results in rabies without pre- or post-exposure prophylaxis, and the disease is nearly always fatal.

Prevalence and Genetic Diversity of Bat Hepatitis B Viruses in Bat Species Living in Gabon.

Hepatitis B virus (HBV) infection leads to around 800,000 deaths yearly and is considered to be a major public health problem worldwide. However, HBV origins remain poorly understood. Here, we looked for bat HBV (BtHBV) in different bat species in Gabon to investigate the role of these animals as carriers of ancestral hepadnaviruses because these viruses are much more diverse in bats than in other host species.

First Detection of Antibodies Specific to Crimean-Congo Hemorrhagic Fever Virus in Rural Populations of Gabon.

Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne viral disease with a mortality rate reaching up to 40% in humans. Currently, CCHF affects three continents: Asia, Europe, and Africa. An increase in confirmed cases in Africa has been observed since 2000.

Morphological, Microstructural, and In Situ Chemical Characteristics of Siderite Produced by Iron-Reducing Bacteria.

Dissimilatory iron-reducing bacteria (DIRB) oxidize organic matter or hydrogen and reduce ferric iron to form Fe(II)-bearing minerals, such as magnetite and siderite. However, compared with magnetite, which was extensively studied, the mineralization process and mechanisms of siderite remain unclear. Here, with the combination of advanced electron microscopy and synchrotron-based scanning transmission X-ray microscopy (STXM) approaches, we studied in detail the morphological, structural, and chemical features of biogenic siderite via a growth experiment with MR-4.

Whole-Genome Characterization of SARS-CoV-2 Reveals Simultaneous Circulation of Three Variants and a Putative Recombination (20B/20H) in Pets, Brazzaville, Republic of the Congo.

Following the emergence of SARS-CoV-2, cases of pets infected with variants circulating among humans were reported. In order to evaluate the occurrence of SARS-CoV-2 circulation among pets in the Republic of the Congo, we conducted a ten-month study of dogs and cats living in COVID-19-positive households in Brazzaville and neighboring localities. Real-time PCR and the Luminex platform were used to detect SARS-CoV-2 RNA and antibodies to SARS-CoV-2 RBD and S proteins, respectively.

Polymer-metal-organic framework self-assembly (PMOFSA) as a robust one-step method to generate well-dispersed hybrid nanoparticles in water.

A new process, PMOFSA, is described here, that opens the way for the one-pot straightforward and versatile manufacture of polymer-MOF nanoparticles in water. It can be expected that this study will not only expand the scope of preparation of polymer-MOF nano-objects but also inspire researchers in the field to prepare a new generation of polymer-MOF hybrid materials.

HPV genotypes in high-grade cervical lesions and invasive cervical carcinoma detected in Gabonese women.

Background: Cervical cancer is the third most common cancer among women worldwide, but particularly affects women living in sub-Saharan Africa. Screening and vaccination programs are two prevention approaches that can reduce cervical cancer incidence. However, effective vaccination campaigns require better knowledge of the prevalence of the main human papillomavirus (HPV) genotypes reported in high-grade neoplastic lesions and invasive carcinomas in women.

Melt processing of paramylon using a water:ionic liquid mixture as plasticizer.

Paramylon is a linear β-1,3-glucan produced by the microalgae Euglena Gracilis. Due to its native crystalline structure, involving hexagonally packed triple helices, paramylon is neither water soluble nor thermoplastic. While such properties are generally obtained by chemical modification of paramylon, the present work demonstrates that using ionic liquid/water mixtures as solvents or plasticizers may be an alternative: A mixture of water with cholinium glycinate (40:60) allowed: i) obtaining paramylon solutions at 80 °C, that form reversible ionogels upon cooling at 20 °C, when used as a solvent, and ii) the thermomechanical processing of paramylon below 100 °C by extrusion and hot-press into transparent films, when used as a plasticizer.

Identification of sulfate-reducing magnetotactic bacteria via a group-specific 16S rDNA primer and correlative fluorescence and electron microscopy: Strategy for culture-independent study.

Magnetotactic bacteria (MTB) biomineralize intracellular magnetic nanocrystals and swim along geomagnetic field lines. While few axenic MTB cultures exist, living cells can be separated magnetically from natural environments for analysis. The bacterial universal 27F/1492R primer pair has been used widely to amplify nearly full-length 16S rRNA genes and to provide phylogenetic portraits of MTB communities.

Intracellular silicification by early-branching magnetotactic bacteria.

Biosilicification-the formation of biological structures composed of silica-has a wide distribution among eukaryotes; it plays a major role in global biogeochemical cycles, and has driven the decline of dissolved silicon in the oceans through geological time. While it has long been thought that eukaryotes are the only organisms appreciably affecting the biogeochemical cycling of Si, the recent discoveries of silica transporter genes and marked silicon accumulation in bacteria suggest that prokaryotes may play an underappreciated role in the Si cycle, particularly in ancient times. Here, we report a previously unidentified magnetotactic bacterium that forms intracellular, amorphous silica globules.

A review of paramylon processing routes from microalga biomass to non-derivatized and chemically modified products.

Paramylon is a linear β-1,3-glucan, similar to curdlan, produced as intracellular granules by the microalga Euglena gracilis, a highly versatile and robust strain, able to grow under various trophic conditions, with valorization of CO wastewaters, or food byproducts as nutrients. This review focuses in particular on the various processing routes leading to new potential paramylon based products. Due to its crystalline structure, involving triple helices stabilized by internal intermolecular hydrogen bonds, paramylon is neither water-soluble nor thermoplastic.

First Evidence of Natural SARS-CoV-2 Infection in Domestic Rabbits.

We tested 144 pet rabbits sampled in France between November 2020 and June 2021 for antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by microsphere immunoassay. We reported the first evidence of a natural SARS-CoV-2 infection in rabbits with a low observed seroprevalence between 0.7% and 1.

Early Circulation of SARS-CoV-2, Congo, 2020.

To determine when severe acute respiratory syndrome coronavirus 2 arrived in Congo, we retrospectively antibody tested 937 blood samples collected during September 2019-February 2020. Seropositivity significantly increased from 1% in December 2019 to 5.3% in February 2020, before the first officially reported case in March 2020, suggesting unexpected early virus circulation.

Contour Fitting of Fused Filaments Cross-Section Images by Lemniscates of Booth: Application to Viscous Sintering Kinetics Modeling.

A method for image analysis was implemented to determine the edge pixels of two biopolymer-based thermoplastic filaments during their hot melt isothermal sintering at 120 °C. Successive inverted ellipses are adjusted to the contour of the sintered filaments and lead to the identification of the parameters of the corresponding lemniscates of Booth. The different steps of the morphological image analysis are detailed, from 8-bit coded acquired images (1 frame/s), to the final fitting of the optimized mathematical functions describing the evolution of the filaments envelope.