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Abstract While the SARS-CoV-2 dynamic has been described globally, there is a lack of data from Sub-Saharan Africa. We herein report the dynamics of SARS-CoV-2 lineages from March 2020 to March 2022 in Cameroon. Of the 760 whole-genome sequences successfully generated by the national genomic surveillance network, 74% were viral sub-lineages of origin and non-variants of concern, 15% Delta, 6% Omicron, 3% Alpha and 2% Beta variants. The pandemic was driven by SARS-CoV-2 lineages of origin in wave 1 (16 weeks, 2.3% CFR), the Alpha and Beta variants in wave 2 (21 weeks, 1.6% CFR), Delta variants in wave 3 (11 weeks, 2.0% CFR), and omicron variants in wave 4 (8 weeks, 0.73% CFR), with a declining trend over time (p = 0.01208). Even though SARS-CoV-2 heterogeneity did not seemingly contribute to the breadth of transmission, the viral lineages of origin and especially the Delta variants appeared as drivers of COVID-19 severity in Cameroon.

Abstract In 2022, many regions around the world experienced a severe respiratory syncytial virus (RSV) epidemic with an earlier-than-usual start and increased numbers of paediatric patients in emergency departments. Here we carried out this study to describe the epidemiology and genetic characteristics of RSV infection in patients hospitalized with severe acute respiratory infections in 2022. Samples were tested for RSV by multiplex real time reverse transcription polymerase chain reaction. Subsequently, a subset of RSV positive samples was selected for NGS sequencing. RSV was detected in 16.04%, among which RSV-A was confirmed in 7.5% and RSV-B in 76.7%. RSV infection were more identified in infants aged ≤ 11 months (83.3%) and a shift in the circulation pattern was observed, with highest incidences between September–November. Phylogenetic analyses revealed that all RSV-A strains belonged to GA2.3.5 genotype and all RSV-B strains to GB5.0.5a genotype. Three putative N-glycosylation sites at amino acid positions 103, 135, 237 were predicted among RSV-A strains, while four N-linked glycosylation sites at positions 81, 86, 231 and 294 were identified in RSV-B strains. Globally, our findings reveal an exclusive co-circulation of two genetic lineages of RSV within the pediatric population in Senegal, especially in infants aged ≤ 11 months.

Abstract During the COVID-19 pandemic in Senegal, contact tracing was done to identify transmission clusters, their analysis allowed to understand their dynamics and evolution. In this study, we used information from the surveillance data and phone interviews to construct, represent and analyze COVID-19 transmission clusters from March 2, 2020, to May 31, 2021. In total, 114,040 samples were tested and 2153 transmission clusters identified. A maximum of 7 generations of secondary infections were noted. Clusters had an average of 29.58 members and 7.63 infected among them; their average duration was 27.95 days. Most of the clusters (77.3%) are concentrated in Dakar, capital city of Senegal. The 29 cases identified as super-spreaders, i.e., the indexes that had the most positive contacts, showed few symptoms or were asymptomatic. Deepest transmission clusters are those with the highest percentage of asymptomatic members. The correlation between proportion of asymptomatic and degree of transmission clusters showed that asymptomatic strongly contributed to the continuity of transmission within clusters. During this pandemic, all the efforts towards epidemiological investigations, active case-contact detection, allowed to identify in a short delay growing clusters and help response teams to mitigate the spread of the disease.

Abstract Akkermansia muciniphila is a human intestinal tract bacterium that plays an important role in the mucus layer renewal. Several studies have demonstrated that it is a modulator for gut homeostasis and a probiotic for human health. The Akkermansia genus contains two species with standing in nomenclature but their genomic diversity remains unclear. In this study, eight new Akkermansia sp. strains were isolated from the human gut. Using the digital DNA-DNA hybridization (dDDH), average nucleotide identity (ANI) and core genome-based phylogenetic analysis applied to 104 A. muciniphila whole genomes sequences, strains were reclassified into three clusters. Cluster I groups A. muciniphila strains (including strain ATCC BAA-835T as type strain), whereas clusters II and III represent two new species. A member of cluster II, strain Marseille-P6666 differed from A. muciniphila strain ATCC BAA-835T and from A. glycaniphila strain PytT in its ability to grow in microaerophilic atmosphere up to 42 °C, to assimilate various carbon sources and to produce acids from a several compounds. The major fatty acids of strain Marseille-P6666 were 12-methyl-tetradecanoic and pentadecanoic acids. The DNA G + C content of strain Marseille-P6666 was 57.8%. On the basis of these properties, we propose the name A. massiliensis sp. nov. for members of cluster II, with strain Marseille-P6666T (= CSUR P6666 = CECT 30548) as type strain. We also propose the name “Candidatus Akkermansia timonensis” sp. nov. for the members of cluster III, which contains only uncultivated strains, strain Akk0196 being the type strain.

Abstract Early predictions forecasted large numbers of severe acute respiratory syndrome coronavirus (SARS-CoV-2) cases and associated deaths in Africa. To date, Africa has been relatively spared. Various hypotheses were postulated to explain the lower than anticipated impact on public health in Africa. However, the contribution of pre-existing immunity is yet to be investigated. In this study, the presence of antibodies against SARS-CoV-2 spike (S) and nucleocapsid (N) proteins in pre-pandemic samples from Africa, Europe, South and North America was examined by ELISA. The protective efficacy of N specific antibodies isolated from Central African donors was tested by in vitro neutralization and in a mouse model of SARS-CoV-2 infection. Antibodies against SARS-CoV-2 S and N proteins were rare in all populations except in Gabon and Senegal where N specific antibodies were prevalent. However, these antibodies failed to neutralize the virus either in vitro or in vivo. Overall, this study indicates that cross-reactive immunity against SARS-CoV-2 N protein was present in Africa prior to the pandemic. However, this pre-existing humoral immunity does not impact viral fitness in rodents suggesting that other human immune defense mechanisms could be involved. In Africa, seroprevalence studies using the N protein are over-estimating SARS-CoV-2 circulation.

Abstract The proprotein convertase PACE4 has demonstrated value as a viable therapeutic target in prostate cancer (PCa). A novel isoform named PACE4-altCT, which arises in neoplastic lesions, plays an important role in tumor progression and has been validated as a pharmacological target. With the discovery of its overexpression in PCa and the alternative splicing of its pre-RNA to generate an oncogenic C-terminally modified isoform named PACE4-altCT, understanding and validating its value as a potential biomarker is of great interest either from prognostic or targeted therapy intervention. Expression of ERG in LNCaP cells was used to investigate the relationship between ERG expression occurring in PCa cells and PACE4-altCT expression by Western blot and qPCR. Using immunohistochemistry, the expression levels of PACE4 isoforms in patient tissues were investigated and correlated with ERG tumor status and Gleason score. An ELISA method was developed using affinity purified recombinant protein and used for quantitative analysis of plasma concentrations of PACE4-altCT and used for correlation. In contrast with the consensual isoform, PACE4-altCT was only strongly overexpressed in prostate cancer patients, correlated with ERG expression levels. Despite its intracellular retention PACE4-altCT could be detected in the plasma of most patients with prostate cancer, whereas it was only found at low levels in normal patients whereas total plasmatic PACE4 levels did not vary significantly between groups. Our study demonstrates that PACE4-altCT is strongly overexpressed in prostate cancer using both immunohistochemical and ELISA techniques and may have some interesting potential as a biomarker.