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

An electrophysiological, behavioural and morphological study of the effects of AMPA lesions of nucleus basalis magnocellularis and of fetal basal forebrain transplants in rats

SIGLEAvailable from British Library Document Supply Centre-DSC:DX203168 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Serological diagnosis of FMD in sheep in Basra by ELISA test

This study was performed to detect the antibodies against the virus-infection- associated antigen (VIAA) in previously diseased and healthy sheep in Basra. The test is valuable in epizootiological surveys because only infected animals with foot and mouth disease virus will give positive reaction without detection of the virus serotypes. 241 sheep sera were collected from 13 suspicious infected sheep flocks with FMD from two major areas in Basra (Abulkhaseeb and Alzubair). All these samples were examined by ELISA test to VIA antigen. It was found -by ELISA- that 71.9% of the total tested sheep sera build specific VIA antibodies against FMD virus, and that 91.7% of the clinically infected sheep gave positive result and that 66.8% of the clinically non-infected sheep were negative. The higher rate of seropositivity in both Abuelkhaseeb and AL-Zubair areas was in the age between 3.5 – 4.5 year (80%) and (81.8%) respectively. The high prevalence of seropositivity to VIA could be due to sub clinical infection or to carrier state and the disease in sheep mild and go un-noticed but important because of transmission to cattle

Natural filler based composite materials

Purpose: The first goal is to get rid of waste and reduce environmental pollution, and the other goal is to investigate the effect of these fibres on properties (resistance of composite materials for bending and tensile testing) of polyester and use them in applications. Also, The moisture environment effect on the properties of composite materials was studied. Design/methodology/approach: It uses natural fibres, which are considered waste, namely eggshell and sawdust with polyester. Several samples were prepared with different weight percentages (30% and 40%), and their mechanical properties were studied and immersed in water for 15 days. And studying the effect of water on these properties. It was found that it is possible to use these fibres (waste) with polyester and benefit from them. It was found that when adding fibres to polyester, the tensile strength decreases, but the bending increases the strength. Finally, it was found that when the samples are immersed in water, the material weakens, and its mechanical properties decrease. Findings: It can be noticed that adding natural fibres by 40% and 30% improved the mechanical properties of polyester in the bending test, where the bending test increased with increased volume fraction of fibre. It can be noticed that adding natural fibres by 40% and 30% decreased the mechanical properties (tensile strength) of polyester in a tensile test. When the natural composite materials were treated with water for 15 days, water decreased the mechanical properties in bending and tensile test. Research limitations/implications: One of the limitations of this research that was found through the work is that when increasing the weight ratios of the fibres added to polyester leads to the failure of polyester, so we recommend using lower weight ratios of fibre. Practical implications: One of the limitations of this research that was found through the work is that when increasing the weight ratios of the fibres added to polyester leads to the failure of polyester, so we recommend using lower weight ratios of fibre. Originality/value: The original value of this research is the use of fibres that are considered waste, their reuse, and utilization in some applications that do not require composite materials with high mechanical properties

Gastroprotective activity of Polygonum chinense aqueous leaf extract on ethanol-induced hemorrhagic mucosal lesions in rats

Polygonum chinense is aMalaysian ethnic plant with various healing effects. This study was to determine preventive effect of aqueous leaf extract of P. chinense against ethanol-induced gastric mucosal injury in rats. Sprague Dawley rats were divided into seven groups. The normal and ulcer control groups were orally administered with distilled water. The reference group was orally administered with 20mg/kg omeprazole. The experimental groups received the extracts 62.5, 125, 250, and 500 mg/kg, accordingly. After sixty minutes, distilled water and absolute ethanol were given (5 mL/kg) to the normal control and the others,respectively. In addition to histology, immunohistochemical and periodic acid schiff (PAS) stains, levels of lipid peroxidation,malondialdehyde (MDA), antioxidant enzymes, and superoxide dismutase (SOD) were measured. The ulcer group exhibited severe mucosal damages. The experimental groups significantly reduced gastric lesions and MDA levels and increased SOD level. Immunohistochemistry of the experimental groups showed upregulation and downregulation of Hsp70 and Bax proteins, respectively. PAS staining in these groups exhibited intense staining as compared to the ulcer group. Acute toxicity study revealed the nontoxic nature of the extract. Our data provide first evidence that P. chinense extract could significantly prevent gastric ulcer

Application of VIC and a routing scheme to Pearl River basin in South China

This paper presents the application of the Variable Infiltration Capacity (VIC), a macroscale hydrological model, to the Pearl River basin in South China. Meteorological data at 1 degree by 1 degree grids from 1951 to 2000 over the region are used to drive the model at a daily time step. The values of the parameters of soil and vegetation data for the model are extracted from two global datasets. A large-scale routing scheme for the VIC model is applied to route the runoff from the upstream to the downstream of the Pearl River. The simulation results are compared with the observed streamflows, at monthly and annual scales, obtained from three streamflow gauge stations. It is observed that the model and routing scheme can give a reasonable simulation.The 16th IAHR-APD Congress and 3rd Symposium of IAHR-ISHS, Hohai University, Nanjing, China, 20-23 October 2008. In Advances in Water Resources and Hydraulic Engineering, 2008, v. 1, p. 72-7