Detection of Alpha- and Betacoronaviruses in Frugivorous and Insectivorous Bats in Nigeria

The rise of bat-associated zoonotic viruses necessitates a close monitoring of their natural hosts. Since the detection of severe acute respiratory syndrome coronavirus (SARS-CoV), it is evident that bats are vital reservoirs of coronaviruses (CoVs). In this study, we investigated the presence of CoVs in multiple bat species in Nigeria to identify viruses in bats at high-risk human contact interfaces. Four hundred and nine bats comprising four bat species close to human habitats were individually sampled from five states in Nigeria between 2019 and 2021. Coronavirus detection was done using broadly reactive consensus PCR primers targeting the RNA-dependent RNA polymerase (RdRp) gene of CoVs. Coronavirus RNA was detected in 39 samples (9.5%, CI 95%: [7.0, 12.8]), of which 29 were successfully sequenced. The identified CoVs in Nigerian bats were from the unclassified African alphacoronavirus lineage and betacoronavirus lineage D (Nobecovirus), with one sample from Hipposideros ruber coinfected with alphacoronavirus and betacoronavirus. Different bat species roosting in similar or other places had CoVs from the same genetic lineage. The phylogenetic and evolutionary dynamics data indicated a high CoV diversity in Nigeria, while host switching may have contributed to CoV evolution. Robust sentinel surveillance is recommended to enhance our knowledge of emerging and re-emerging coronaviruses

Molecular characterization of non-aureus staphylococci and Mammaliicoccus from Hipposideros bats in Southwest Nigeria

Bats are not only ecologically valuable mammals but also reservoirs of zoonotic pathogens. Their vast population, ability to fly, and inhabit diverse ecological niches could play some role in the spread of antibiotic resistance. This study investigated non-aureus staphylococci and Mammaliicoccus colonization in the Hipposideros bats at Obafemi Awolowo University, Ile-Ife, Nigeria. Pharyngeal samples (n = 23) of the insectivorous bats were analyzed, and the presumptive non-aureus staphylococcal and Mammaliicoccus isolates were confirmed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). The isolates were characterized based on antibiotic susceptibility testing and whole-genome sequencing (WGS). Six bacterial genomes were assembled, and three species were identified, including Mammaliicoccus sciuri (n = 4), Staphylococcus gallinarum (n = 1), and Staphylococcus nepalensis (n = 1). All the isolates were resistant to clindamycin, while the M. sciuri and S. gallinarum isolates were also resistant to fusidic acid. WGS analysis revealed that the M. sciuri and S. gallinarum isolates were mecA-positive. In addition, the M. sciuri isolates possessed some virulence (icaA, icaB, icaC, and sspA) genes. Multi-locus sequence typing identified two new M. sciuri sequence types (STs) 233 and ST234. The identification of these new STs in a migratory mammal deserves close monitoring because previously known ST57, ST60, and ST65 sharing ack (8), ftsZ (13), glpK (14), gmk (6), and tpiA (10) alleles with ST233 and ST234 have been linked to mastitis in animals. Moreover, the broad host range of M. sciuri could facilitate the dispersal of antibiotic resistance genes. This study provides evidence of the importance of including migratory animals in monitoring the development and spread of antibiotic resistance

Emergence and spread of two SARS-CoV-2 variants of interest in Nigeria.

Identifying the dissemination patterns and impacts of a virus of economic or health importance during a pandemic is crucial, as it informs the public on policies for containment in order to reduce the spread of the virus. In this study, we integrated genomic and travel data to investigate the emergence and spread of the SARS-CoV-2 B.1.1.318 and B.1.525 (Eta) variants of interest in Nigeria and the wider Africa region. By integrating travel data and phylogeographic reconstructions, we find that these two variants that arose during the second wave in Nigeria emerged from within Africa, with the B.1.525 from Nigeria, and then spread to other parts of the world. Data from this study show how regional connectivity of Nigeria drove the spread of these variants of interest to surrounding countries and those connected by air-traffic. Our findings demonstrate the power of genomic analysis when combined with mobility and epidemiological data to identify the drivers of transmission, as bidirectional transmission within and between African nations are grossly underestimated as seen in our import risk index estimates

A year of genomic surveillance reveals how the SARS-CoV-2 pandemic unfolded in Africa.

The progression of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic in Africa has so far been heterogeneous, and the full impact is not yet well understood. In this study, we describe the genomic epidemiology using a dataset of 8746 genomes from 33 African countries and two overseas territories. We show that the epidemics in most countries were initiated by importations predominantly from Europe, which diminished after the early introduction of international travel restrictions. As the pandemic progressed, ongoing transmission in many countries and increasing mobility led to the emergence and spread within the continent of many variants of concern and interest, such as B.1.351, B.1.525, A.23.1, and C.1.1. Although distorted by low sampling numbers and blind spots, the findings highlight that Africa must not be left behind in the global pandemic response, otherwise it could become a source for new variants

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

Investment in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing in Africa over the past year has led to a major increase in the number of sequences that have been generated and used to track the pandemic on the continent, a number that now exceeds 100,000 genomes. Our results show an increase in the number of African countries that are able to sequence domestically and highlight that local sequencing enables faster turnaround times and more-regular routine surveillance. Despite limitations of low testing proportions, findings from this genomic surveillance study underscore the heterogeneous nature of the pandemic and illuminate the distinct dispersal dynamics of variants of concern-particularly Alpha, Beta, Delta, and Omicron-on the continent. Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve while the continent faces many emerging and reemerging infectious disease threats. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

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

Histopathological Alterations In Gills Of Fingerlings Of Clarias Gariepinus (Burchell, 1822) Following Sublethal Acute Exposure To Hevea Brasiliensis

Abstract: Studies on the toxic effects of water soluble fraction (WSF) of Hevea brasiliensis on the histology of the gills of Clarias gariepinus fingerlings showed severe impacts on the gills of the test organisms. Six concentrations were prepared from the water soluble fraction of the latex (0, 30, 40, 50, 60 and 70mg/l) for histopathological examination on the gills of the species. In the control group there was no histological change on the test organism. Gill samples for histological examination were prepared from the concentrations which toxic manifestation of the toxicant was observed. There was no toxic manifestation on the control (0mg/l), 30mg/l and in the 40mg/l of concentration, whereas the test organism in the 50mg/l, 60mg/l and 70mg/l concentration exhibited various reactions which included, erratic movement, vertical swimming position, colour changes, weaken swimming motions, and changes in opercula rate. In the 50mg/l concentration the gill showed disintegration of cells in gill, in the 60mg/l concentration it was observed to show Lamellae erosion and fusion of cells and in the 70mg/l concentration Pronounced lamellae erosion was observed in gill ray. Therefore, if latex obtained from Hevea brasiliensis finds its way into the aquatic environment as would be expected, it will cause deleterious ecological effects to both terrestrial and aquatic biota at the long term. Realizing the tremendous adverse effects associated with WSF of the latex from H. brasilensis, safety measures should be adhere by companies using rubber latex has their raw material

Genomic characterization of Alphacoronavirus from Mops condylurus bats in Nigeria

Coronaviruses (CoVs) are responsible for sporadic, epidemic and pandemic respiratory diseases worldwide. Bats have been identified as the reservoir for CoVs. To increase the number of complete coronavirus genomes in Africa and to comprehend the molecular epidemiology of bat Alphacoronaviruses (AlphaCoVs), we used deep metagenomics shotgun sequencing to obtain three (3) near-complete genomes of AlphaCoVs from Mops condylurus (Angolan free-tailed) bat in Nigeria. Phylogenetic and pairwise identity analysis of open reading frame 1ab (ORF1ab), spike (S), envelope (E), membrane (M) and nucleocapsid (N) genes of AlphaCoV in this study to previously described AlphaCoVs subgenera showed that the Nigerian AlphaCoVs may be members of potentially unique AlphaCoV subgenera circulating exclusively in bats in the Molossidae bat family. Recombination events were detected, suggesting the evolution of AlphaCoVs within the Molossidae family. The pairwise identity of the S gene in this study and previously published S gene sequences of other AlphaCoVs indicate that the Nigerian strains may have a genetically unique spike protein that is distantly related to other AlphaCoVs. Variations involving non-polar to polar amino acid substitution in both the Heptad Repeat (HR) regions 1 and 2 were observed. Further monitoring of bats to understand the host receptor use requirements of CoVs and interspecies CoV transmission in Africa is necessary to identify and prevent the potential danger that bat CoVs pose to public health

Cytotoxic action of the leaves of Uvaria chamae P.Beauv. and Dicliptera paniculata (Forssk.) I.Darbysh. from Nigeria mediated through intrinsic apoptotic pathway induction in four cancer cell lines

Background: Over the years, the morbidity and mortality due to cancer have continued to increase worldwide. Plants are well utilized in Nigeria ethno-medicine for cancer treatment. However, scientific evidence, particularly at the molecular level, has been lacking, and biodiversity loss is a threat. Aim of the study: The cytotoxic activity of the leaves of six plants used in Nigeria ethno-medicine was investigated and the molecular pathway of cytotoxic action of two active extracts on four cancer cell lines (A549, RD, MCF-7, and HeLa) was also assessed. Materials and methods: Cytotoxic activities of the plant extracts were assessed on breast (MCF-7), lung (A549), cervical (HeLa), adenocarcinoma and rhabdomyosarcoma (RD) cells using MTT cell viability assay in a time-dependent manner. The sandwich ELISA method was used to assess the protein expressions (Bcl-2, BAX, and executioner caspase 3) involved in the apoptotic pathway in cancer cells after treatment with cytotoxic extracts. UHPLC-MS/MS approach was used to analyze the possible bioactive phytochemicals of the cytotoxic plant extract. Results: Uvaria chamae and Dicliptera paniculata extracts displayed good cytotoxicity across all cell lines in a time- and concentration-dependent manner (CC50 <30 µg/mL). Increased pro-apoptotic BAX and lowered expression of anti-apoptotic Bcl-2 show the cytotoxic action of the two extracts followed the intrinsic apoptotic pathway compared to untreated cells. The increased expression of executioner caspase 3 indicated that the intrinsic apoptotic pathway was caspase-dependent. Conclusion: The anticancer potential of U. chamae and D. paniculata in this study validates the use of these plants in Nigerian ethno-medicine, highlighting apoptosis as a molecular pathway of their cytotoxicity