Publications by authors named "Eric LeRoy"

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

In-depth statistics of individual defects observed during transmission electron microscopy (TEM) experiments are essential for the thorough characterization of materials. In this study, we aim to quantitatively characterize the population of dislocation loops in ion-irradiated CrFeMnNi alloys. To this end, we propose an efficient guideline to prepare TEM micrographs dataset for deep learning analysis, adapted for accurate characterization of microstructures produced by thousands of overlapping defects, a very common situation in TEM images, unfeasible by previous existing methods.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF
Article Synopsis
  • - Caliciviruses and astroviruses are major causes of non-bacterial foodborne illnesses and gastroenteritis in humans, with rodents being key hosts for these viruses and many zoonotic pathogens that can affect humans.
  • - A study screened 245 rodent intestine samples for these viruses, finding no caliciviruses but detecting astroviruses in 18 samples, specifically from the Rattus rattus species.
  • - Phylogenetic analysis revealed that the detected astroviruses are closely related to strains found in Gabon, Kenya, and Asia, indicating that transportation methods may promote the spread of these viruses through rodent populations.
View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF
Article Synopsis
  • * Researchers found that 4 out of 163 tested wild ruminants were positive for RVFV, with a genetic link to a virus from Namibia, indicating RVF's presence in Gabon's wildlife.
  • * In a separate survey of 306 domestic animals, they found 15.4% had RVFV-specific antibodies, predominantly in goats, emphasizing the need for improved surveillance and control measures for RVF in the region.
View Article and Find Full Text PDF
Article Synopsis
  • - Coronaviruses are a diverse group of viruses that can infect various animals, including humans, with some strains like SARS-CoV-1, SARS-CoV-2, and MERS-CoV affecting global health significantly and originating from bats through intermediary hosts.
  • - A study in Gabon screened 229 faecal samples from wild great apes and mandrills for coronaviruses using nested PCR, but all samples tested negative for CoVs.
  • - The negative results might be due to a small sample size, the temporary nature of infections, or the unsuitability of faecal samples for detection, indicating the need for future studies using larger sample sizes and alternative non-invasive methods to better understand CoV circulation
View Article and Find Full Text PDF
Article Synopsis
  • - The study focused on screening astroviruses (AstVs), enteroviruses (EVs), and caliciviruses (CaVs) in domestic animals to understand their potential to spread zoonotic diseases in rural Central Africa, where these animals interact closely with wildlife.
  • - Researchers collected rectal swabs from 123 goats, 41 sheep, and 76 dogs across 10 villages in northeastern Gabon, using PCR to detect various viruses by amplifying specific genes.
  • - Out of 240 samples, 23 tested positive for the viruses, with the majority found in goats, and some sequences clustering with known viruses that could pose a risk to humans, suggesting these animals could harbor pathogens that affect human health.
View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

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.

View Article and Find Full Text PDF

Background: Domestic pets can contract severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection; however, it is unknown whether the UK B.1.1.

View Article and Find Full Text PDF

Although there are several reports in the literature of SARS-CoV-2 infection in cats, few SARS-CoV-2 sequences from infected cats have been published. In this study, SARS-CoV-2 infection was evaluated in two cats by clinical observation, molecular biology (qPCR and NGS), and serology (microsphere immunoassay and seroneutralization). Following the observation of symptomatic SARS-CoV-2 infection in two cats, infection status was confirmed by RT-qPCR and, in one cat, serological analysis for antibodies against N-protein and S-protein, as well as neutralizing antibodies.

View Article and Find Full Text PDF

Despite the probable zoonotic origin of SARS-CoV-2, only limited research efforts have been made to understand the role of companion animals in SARS-CoV-2 epidemiology. According to recent serological prevalence studies, human-to-companion animal transmission is quite frequent, which led us to consider that the risk of SARS-CoV-2 transmission from animal to human, albeit negligible in the present context, may have been underestimated. In this study, we provide the results of a prospective survey that was conducted to evaluate the SARS-CoV-2 isolation rate by qRT-PCR in dogs and cats with different exposure risks and clinical statuses.

View Article and Find Full Text PDF

In the battle to quickly identify potential yellow fever arbovirus outbreaks in the Democratic Republic of the Congo, active syndromic surveillance of acute febrile jaundice patients across the country is a powerful tool. However, patients who test negative for yellow fever virus infection are too often left without a diagnosis. By retroactively screening samples for other potential viral infections, we can both try to find sources of patient disease and gain information on how commonly they may occur and co-occur.

View Article and Find Full Text PDF