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

The Origin and Evolutionary History of HIV-1 Subtype C in Senegal

Background: The classification of HIV-1 strains in subtypes and Circulating Recombinant Forms (CRFs) has helped in tracking the course of the HIV pandemic. In Senegal, which is located at the tip of West Africa, CRF02_AG predominates in the general population and Female Sex Workers (FSWs). In contrast, 40% of Men having Sex with Men (MSM) in Senegal are infected with subtype C. In this study we analyzed the geographical origins and introduction dates of HIV-1 C in Senegal in order to better understand the evolutionary history of this subtype, which predominates today in the MSM population Methodology/Principal Findings: We used a combination of phylogenetic analyses and a Bayesian coalescent-based approach, to study the phylogenetic relationships in pol of 56 subtype C isolates from Senegal with 3,025 subtype C strains that were sampled worldwide. Our analysis shows a significantly well supported cluster which contains all subtype C strains that circulate among MSM in Senegal. The MSM cluster and other strains from Senegal are widely dispersed among the different subclusters of African HIV-1 C strains, suggesting multiple introductions of subtype C in Senegal from many different southern and east African countries. More detailed analyses show that HIV-1 C strains from MSM are more closely related to those from southern Africa. The estimated date of the MRCA of subtype C in the MSM population in Senegal is estimated to be in the early 80's. Conclusions/Significance: Our evolutionary reconstructions suggest that multiple subtype C viruses with a common ancestor originating in the early 1970s entered Senegal. There was only one efficient spread in the MSM population, which most likely resulted from a single introduction, underlining the importance of high-risk behavior in spread of viruses

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

Hepatitis B virus (HBV) infection amongst children in Senegal: current prevalence and seroprotection level

Introduction: hepatitis B virus (HBV) infection is highly endemic in Senegal. HBV vaccine of all children has been introduced in 1999 and included in the Expanded Programme on Immunization in 2004. The aim of this study was to assess the HBV prevalence and immunity status against HBV amongst children in Senegal. Methods: between March and August 2016, consecutive children aged from 6 months to 16 years old were recruited in outpatient department of three main children hospitals in Senegal. Serum samples were analyzed for HBV serology (HBsAg, HBcAb, HBsAb) using ARCHITECT analyzer. Children with HBsAb levels ≥ 10 IU/l) were considered as seroprotected against HBV. Results: during the study period, 295 children fulfilled the criteria for the study and were further analyzed. Three children were HBsAg positive giving a seroprevalence at 1.1% (95% CI: 0.2-3.3), 12/267 (4.5%, 95% CI=2.3-7.7) had positive HBcAb and 226/295 (76.6%, 71.4-81.3) had positive HBsAb including 191 (77.3%, 71.6-82.4) with isolated HBsAb related to previous active immunization. However only 165 children (56%, CI 50-62) had seroprotective HBsAb levels (HBsAb ≥ 10 UI/L) and 63 (21.4, 16.8-26) had a strong seroprotectiondefined by HBsAb ≥ 100 IU/L. Conclusion: our results suggest that although HBV prevalence has significantly decreased in children in Senegal following a better HBV vaccine coverage, the number of children correctly seroprotected is insufficient (56%). Assessing the levels of&nbsp

Genomic Epidemiology of SARS-CoV-2 in Urban Settings in Senegal

We used whole genome sequencing to identify and analyze mutations in SARS-CoV-2 in urban settings during the deadliest wave of the COVID-19 epidemic—from March to April 2021—in Senegal. Nasopharyngeal samples testing positive for SARS-CoV-2 were sequenced on the Illumina NovaSeq 6000 sequencing system using the COVIDSeq protocol. A total of 291 genotypable consensus genome sequences were obtained. Phylogenetic analyses grouped the genomes into 16 distinct PANGOLIN lineages. The major lineage was B.1.1.420, despite circulation of the Alpha variant of concern (VOC). A total of 1125 different SNPs, identified relative to the Wuhan reference genome, were detected. These included 13 SNPs in non-coding regions. An average density of 37.2 SNPs per 1000 nucleotides was found, with the highest density occurring in ORF10. This analysis allowed, for the first time, the detection of a Senegalese SARS-CoV-2 strain belonging to the P.1.14 (GR/20J, Gamma V3) sublineage of the Brazilian P.1 lineage (or Gamma VOC). Overall, our results highlight substantial SARS-CoV-2 diversification in Senegal during the study period

HIV-1 genetic diversity and primary drug resistance mutations before large-scale access to antiretroviral therapy, Republic of Congo

Abstract Background In this work, we investigated the genetic diversity of HIV-1 and the presence of mutations conferring antiretroviral drug resistance in 50 drug-naïve infected persons in the Republic of Congo (RoC). Samples were obtained before large-scale access to HAART in 2002 and 2004. Methods To assess the HIV-1 genetic recombination, the sequencing of the pol gene encoding a protease and partial reverse transcriptase was performed and analyzed with updated references, including newly characterized CRFs. The assessment of drug resistance was conducted according to the WHO protocol. Results Among the 50 samples analyzed for the pol gene, 50% were classified as intersubtype recombinants, charring complex structures inside the pol fragment. Five samples could not be classified (noted U). The most prevalent subtypes were G with 10 isolates and D with 11 isolates. One isolate of A, J, H, CRF05, CRF18 and CRF37 were also found. Two samples (4%) harboring the mutations M230L and Y181C associated with the TAMs M41L and T215Y, respectively, were found. Conclusion This first study in the RoC, based on WHO classification, shows that the threshold of transmitted drug resistance before large-scale access to antiretroviral therapy is 4%

Surveillance of transmitted HIV-1 antiretroviral drug resistance in the context of decentralized HIV care in Senegal and the Ebola outbreak in Guinea

Abstract Objectives Disruption in HIV care provision may enhance the development and spread of drug resistance due to inadequate antiretroviral therapy. This study thus determined the prevalence of HIV-1 transmitted drug resistance (TDR) in settings of decentralized therapy and care in Senegal and, the Ebola outbreak in Guinea. Antiretroviral-naïve patients were enrolled following a modified WHO TDR Threshold Survey method, implemented in Senegal (January–March 2015) and Guinea (August–September 2015). Plasma and dried blood spots specimens, respectively from Senegalese (n = 69) and Guinean (n = 50) patients, were collected for direct sequencing of HIV-1 pol genes. The Stanford Calibrated Population Resistance program v6.0 was used for Surveillance Drug Resistance Mutations (SDRMs). Results Genotyping was successful from 54/69 (78.2%) and 31/50 (62.0%) isolates. In Senegal, TDR prevalence was 0% (mean duration since HIV diagnosis 4.08 ± 3.53 years). In Guinea, two patients exhibited SDRMs M184V (NRTI), T215F (TAM) and, G190A (NNRTI), respectively. TDR prevalence at this second site, however, could not be ascertained because of low sample size. Phylogenetic inference confirmed CRF02_AG predominance in Senegal (62.96%) and Guinea (77.42%). TDR prevalence in Senegal remains extremely low suggesting improved control measures. Continuous surveillance in both settings is mandatory and, should be done closest to diagnosis/transmission time and with larger sample size

Effectiveness of the prevention of HIV mother -to-child transmission (PMTCT) program via early infant diagnosis (EID) data in Senegal.

BACKGROUND:To improve the care and treatment of HIV-exposed children, early infant diagnosis (EID) using dried blood spot (DBS) sampling has been performed in Senegal since 2007, making molecular diagnosis accessible for patients living in decentralized settings. This study aimed to determine the evolution of the HIV transmission rate in children from 2008 to 2015 and to analyze associated factors, particularly the mother's treatment status and/or child's prophylaxis status and the feeding mode. METHODS:The data were analyzed using EID reports from the reference laboratory. Information related to sociodemographic characteristics, HIV profiles, the mother's treatment status, the child's prophylaxis status, and the feeding mode was included. Descriptive statistics were calculated, and bivariate and multivariate logistic regression analyses were performed. RESULTS:During the study period, a total of 5418 samples (5020 DBS and 398 buffy coat) from 168 primary prevention of HIV mother-to-child transmission (PMTCT) intervention sites in Senegal were tested. The samples were collected from 4443 children with a median age of 8 weeks (1-140 weeks) and a sex ratio (M/F) of 1.1 (2309/2095). One-third (35.2%; N = 1564) of the children were tested before 6 weeks of age. Twenty percent (N = 885) underwent molecular diagnostic testing more than once. An increased number of mothers receiving treatment (57.4%; N = 2550) and children receiving prophylaxis (52.1%; N = 2315) for protection against HIV infection during breastfeeding was found over the study period. The transmission rate decreased from 14.8% (95% confidence interval (CI): 11.4-18.3) in 2008 to 4.1% (95% CI: 2.5-7.5) in 2015 (p < 0.001). However, multivariate logistic regression analysis revealed that independent predictors of HIV mother-to-child transmission included lack of mother's treatment (adjusted odd ratio (aOR) = 3.8, 95% CI: 1.9-7.7; p˂0.001), lack of child's prophylaxis (aOR = 7.8, 95% CI: 1.7-35.7; p = 0.009), infant age at diagnosis (aOR = 2.2, 95% CI: 1.1-4.3 for ≤6 weeks versus 12-24 weeks; p = 0.025) and protective effect of breastfeeding on ART against formula feeding (aOR = 0.4, 95% CI: 0.2, 0.7; p = 0.005). CONCLUSION:This study demonstrates the effectiveness of PMTCT interventions in Senegal but indicates also that increased efforts should be continued to reduce the MTCT rate to less than 2%