Quality assurance for hepatitis C virus point-of-care diagnostics in sub-Saharan Africa

As part of a multinational study to evaluate the Bioline Hepatitis C virus (HCV) point-of- care (POC) testing in sub-Saharan Africa (SSA), this narrative review summarises regulatory standards and quality indicators for validating and approving HCV clinical diagnostics. In addition, this review also provides a summary of their diagnostic evaluations using the REASSURED criteria as the benchmark and its implications on the WHO HCV elimination goals 2030.https://www.mdpi.com/journal/diagnosticsam2024School of Health Systems and Public Health (SHSPH)SDG-03:Good heatlh and well-bein

B-cell epitopes of African horse sickness virus serotype 4 recognised by immune horse sera

Identifying antigenic proteins and mapping their epitopes is important for the development of diagnostic reagents and recombinant vaccines. B-cell epitopes of African horse sickness virus (AHSV) have previously been mapped on VP2, VP5, VP7 and NS1, using mouse, rabbit and chicken monoclonal antibodies. A comprehensive study of the humoral immune response of five vaccinated horses to AHSV-4 antigenic peptides was undertaken. A fragmented-genome phage display library expressing a repertoire of AHSV-4 peptides spanning the entire genome was constructed. The library was affinity selected for binders on immobilised polyclonal immunoglobulin G (IgG) isolated from horse sera collected pre- and post-immunisation with an attenuated AHSV-4 monovalent vaccine. The DNA inserts of binding phages were sequenced with Illumina high-throughput sequencing. The data were normalised using preimmune IgG-selected sequences. More sequences mapped to the genes coding for NS3, VP6 and VP5 than to the other genes. However, VP2 and VP5 each had more antigenic regions than each of the other proteins. This study identified a number of epitopes to which the horse’s humoral immune system responds during immunisation with AHSV-4.The Economic Competitiveness Support Programme, ARC-OVI, South Africahttp://www.ojvr.orgam2017Veterinary Tropical Disease

Barriers and enablers for implementation of digital-linked diagnostics models at point-of-care in South Africa : stakeholder engagement

AVAILABILITY OF DATA AND MATERIALS : All data analyzed in the study is available upon written request from the corresponding author.The integration of digital technologies holds significant promise in enhancing accessibility to disease diagnosis and treatment at point-of-care (POC) settings. Effective implementation of such interventions necessitates comprehensive stakeholder engagements. This study presents the outcomes of a workshop conducted with key stakeholders, aiming to discern barriers and enablers in implementing digital-connected POC diagnostic models in South Africa. The workshop, a component of the 2022 REASSURED Diagnostics symposium, employed the nominal group technique (NGT) and comprised two phases: Phase 1 focused on identifying barriers, while Phase 2 centered on enablers for the implementation of digital-linked POC diagnostic models. Stakeholders identified limited connectivity, restricted offline functionality, and challenges related to load shedding or rolling electricity blackouts as primary barriers. Conversely, ease of use, subsidies provided by the National Health Insurance, and 24-h assistance emerged as crucial enablers for the implementation of digital-linked POC diagnostic models. The NGT workshop proved to be an effective platform for elucidating key barriers and enablers in implementing digital-linked POC diagnostic models. Subsequent research endeavors should concentrate on identifying optimal strategies for implementing these advanced diagnostic models in underserved populations.The workshop in which the study was conducted was part of the 1st REASSURED Diagnostics Symposium which was funded by the US Embassy’s US Partnership initiative.https://bmchealthservres.biomedcentral.comhj2024Nuclear MedicineRadiologySchool of Health Systems and Public Health (SHSPH)Non

m-PIMA™ HIV1/2 VL : a suitable tool for HIV-1 and HIV-2 viral load quantification in West Africa

DATA AVAILABILITY : Data will be made available on request.Please read abstract in the article.The Clinton Health Access Initiative (CHAI) and the UNICEF Senegal and Abbott Diagnostics.https://www.elsevier.com/locate/jviromethj2024School of Health Systems and Public Health (SHSPH)Non

Identifying B-cell epitopes of African horse sickness virus serotype 4 recognised by antisera of immunised horses

African horse sickness is an infectious, insect-borne but non-contagious disease of equids responsible for more than 95% mortality in naïve horses. The African horse sickness virus has ten segments of double stranded RNA encoding seven structural and three non-structural proteins. There is currently no cure for the disease and one of the effective ways to control or prevent new infection is by vaccination. Although successful, the currently used vaccine is not registered for use outside the sub- Saharan region because of fears of reversal to virulence. Inactivated and subunit vaccines have been tested but are not commercially available. Research towards recombinant vaccines that will offer protection without these limitations is thus ongoing. Identification and characterisation of antigenic regions on proteins has always been essential in the development of vaccines and immunodiagnostic reagents. AHSV proteins have been shown to confer protection to model animals in one form or another. This study was undertaken to investigate the global humoral immune reaction during immunisation in horses. This was done using sera from immunised horses and a genome-targeted phage display library. A phage library expressing a repertoire of AHSV-4 peptides large enough to represent the whole genome was constructed. The library was affinity selected with purified naïve (day 0) and immunised (day 28, day 52) horse IgGs and a pool of phages expressing binding peptides were isolated. The DNA inserts of the pool of phages were subjected to high throughput sequencing and sequences identified by matching them to the AHSV-4 genome. Analysis of the extensive data output selected by the naive and immunised IgGs enabled a thorough examination of the panning process. Sequences were normalised by subtracting the naïve from the immunised sequences. Comparing the sequences selected with day 28 IgG enabled identification of 16 potentially antigenic regions recognised by most horses. Some of these regions could easily have been missed with the traditional clone picking approach. Some of the regions were also selected by most horses with day 52 IgG, indicating persistent antibodies. Potentially antigenic regions were identified without the functional re-testing which is common part of traditional phage display. This was due to lack of access to the single clones in the library. One way to confirm binding of selected regions is by peptide ELISA, which was started in this study. This study improved on all the phage display work already done on orbiviruses and offered more information on the immunogenicity of AHSV-4 in horses. Future work should focus on confirming antigenicity of the selected regions. The potential antigenic regions could be fused with T-cell epitopes, identified in a parallel study, to form a construct that might induce production of humoral and cellular immune responses.Dissertation (MSc)--University of Pretoria, 2015.tm2016Veterinary Tropical DiseasesMS

Quality Assurance for Hepatitis C Virus Point-of-Care Diagnostics in Sub-Saharan Africa

As part of a multinational study to evaluate the Bioline Hepatitis C virus (HCV) point-of-care (POC) testing in sub-Saharan Africa (SSA), this narrative review summarises regulatory standards and quality indicators for validating and approving HCV clinical diagnostics. In addition, this review also provides a summary of their diagnostic evaluations using the REASSURED criteria as the benchmark and its implications on the WHO HCV elimination goals 2030

B-cell epitopes of African horse sickness virus serotype 4 recognised by immune horse sera

Identifying antigenic proteins and mapping their epitopes is important for the development of diagnostic reagents and recombinant vaccines. B-cell epitopes of African horse sickness virus (AHSV) have previously been mapped on VP2, VP5, VP7 and NS1, using mouse, rabbit and chicken monoclonal antibodies. A comprehensive study of the humoral immune response of five vaccinated horses to AHSV-4 antigenic peptides was undertaken. A fragmented-genome phage display library expressing a repertoire of AHSV-4 peptides spanning the entire genome was constructed. The library was affinity selected for binders on immobilised polyclonal immunoglobulin G (IgG) isolated from horse sera collected pre- and post-immunisation with an attenuated AHSV-4 monovalent vaccine. The DNA inserts of binding phages were sequenced with Illumina high-throughput sequencing. The data were normalised using preimmune IgG-selected sequences. More sequences mapped to the genes coding for NS3, VP6 and VP5 than to the other genes. However, VP2 and VP5 each had more antigenic regions than each of the other proteins. This study identified a number of epitopes to which the horse’s humoral immune system responds during immunisation with AHSV-4

REASSURED diagnostics at point-of-care in sub-Saharan Africa: A scoping review.

Point-of-care (POC) diagnostics that meet the REASSURED criteria are essential in combating the rapid increase and severity of global health emergencies caused by infectious diseases. However, little is known about whether the REASSURED criteria are implemented in regions known to have a high burden of infectious diseases such as sub-Saharan Africa (SSA). This scoping review maps evidence of the use of REASSURED POC diagnostic tests in SSA. The scoping review was guided by the advanced methodological framework of Arksey and O'Malley, and Levac et al. We searched the following electronic databases for relevant literature: Scopus, Dimensions, ProQuest Central, Google Scholar, and EBSCOhost (MEDLINE, CINAHL, as well as AFRICA-WIDE). Two reviewers independently screened abstracts and full-text articles using the inclusion criteria as reference. We appraised the quality of the included studies using the mixed-method appraisal tool (MMAT) version 2018. We retrieved 138 publications, comprising 134 articles and four grey literature articles. Of these, only five articles were included following abstract and full-text screening. The five included studies were all conducted in SSA. The following themes emerged from the eligible articles: quality assurance on accuracy of REASSURED POC diagnostic tests, sustainability of REASSURED POC diagnostic tests, and local infrastructure capability for delivering REASSURED POC diagnostic tests to end users. All five articles had MMAT scores between 90% and 100%. In conclusion, our scoping review revealed limited published research on REASSURED diagnostics at POC in SSA. We recommend primary studies aimed at investigating the implementation of REASSURED POC diagnostic tests in SSA