Prevalence of high-risk human papillomavirus genotypes and viral load correlated with squamous cell inflammation among women in Gabon.

BACKGROUND: High-risk genotypes of Human Papillomavirus are responsible for 90% of cases of cervical cancer worldwide. Inflammation of squamous cells is mainly linked to HPV. In Gabon, HPV is endemic and circulates among the female population. The study aimed to determine the prevalence of HR-HPV genotypes and to investigate the correlation between squamous cell inflammation and HPV viral load in infected women in Gabon. METHODS: The cross-sectional study was conducted at Libreville University Hospital Center (UHC) and National Public Health Laboratory from March to May 2024 among 399 women. Two cervical smears were taken. Genotype detection was carried out by multiplex fluorescence real-time PCR in the NPHL virology unit. Cytology was carried out in UHC's anatomic-pathology laboratory. Data were analyzed by SPSS software. Graphs were plotted using Microsoft Excel 2016. RESULTS: The prevalence of Human Papillomavirus was 26.1% (95% CI: 22-30.6). The prevalence of HR-HPV genotypes was 24.8%. The most common HR-HPV genotypes were HPV-16/52/18/35/56/58/53/68. The rate of multiple HPV infections was 29.8% and 95.2% for the HR-HPV infection rate. Viral load was significantly correlated with squamous cell inflammation (r = 0.977 and P = 0.001). CONCLUSION: HR-HPV infection remains a concern in women, however early screening is necessary for optimal monitoring and management. HR-HPV viral load is a predictive marker of squamous cell inflammation.

HIV-1 residual risk and pre-treatment drug resistance among blood donors: A sentinel surveillance from Gabon.

BACKGROUND: Surveillance of HIV-1 pre-treatment drug resistance (PDR) is essential for ensuring the success of first-line antiretroviral therapy (ART). Beside population-based surveys, sentinel surveillance of PDR and circulating HIV-1 clades in specific populations such as blood donors could efficiently inform decision-making on ART program. We therefore sought to ascertain HIV-1 residual infection, the threshold of PDR and viral diversity among recently-diagnosed blood donors in Gabon. METHODS: A sentinel surveillance was conducted among 381 consenting blood donors at the National Blood Transfusion Center (NBTC) in Gabon from August 3,2020 to August, 31, 2021. In order to determine the residual risk of HIV transmission, viral load and HIV-1 Sanger-sequencing were performed at the Chantal BIYA International Reference Center (CIRCB)-Cameroon on HIV samples previously tested seronegative with ELISA in Gabon. Phylogeny was performed using MEGA X, PDR threshold>10% was considered high and data were analysed using p≤0.05 for statistical significance. RESULTS: Five HIV-negative blood donors had a detectable viral load indicating a high residual risk of HIV transmission. Among the samples successfully sequenced, four participants had major drug resistance mutations (DRMs), giving a threshold of PDR of 25% (4/16). By drug class, major DRMs targeting NNRTI (K103N, E138G), NRTIs (L210W) and PI/r (M46L). The most representative viral clades were CRF02_AG and subtype A1. The genetic diversity of HIV-1 had no significant effect on the residual risk in blood transfusion (CRF02_AG, P = 0.3 and Recombinants, P = 0.5). CONCLUSION: This sentinel surveillance indicates a high residual risk of HIV-1 transfusion in Gabon, thereby underscoring the need for optimal screening strategy for blood safety. Moreover, HIV-1 transmission goes with high-risk of PDR, suggesting suboptimal efficacy of ART. Nonetheless, the genetic diversity has limited (if any effect) on the residual risk of infection and PDR in blood donors.

SARS-CoV-2 genomic surveillance and reliability of PCR single point mutation assay (SNPsig® SARS-CoV-2 EscapePLEX CE) for the rapid detection of variants of concern in Cameroon.

Background: Surveillance of SARS-CoV-2 variants of concern (VOCs) and lineages is crucial for decision-making. Our objective was to study the SARS-CoV-2 clade dynamics across epidemiological waves and evaluate the reliability of SNPsig® SARS-CoV-2 EscapePLEX CE in detecting VOCs in Cameroon. Material and methods: A laboratory-based study was conducted on SARS-CoV-2 positive nasopharyngeal specimens cycle threshold (Ct)≤30 at the Chantal BIYA International Reference Centre in Yaoundé-Cameroon, between April-2020 to August-2022. Samples were analyzed in parallel with Sanger sequencing and (SNPsig® SARS-CoV-2 EscapePLEX CE), and performance characteristics were evaluated by Cohen's coefficient and McNemar test. Results: Of the 130 sequences generated, SARS-CoV-2 clades during wave-1 (April-November 2020) showed 97 % (30/31) wild-type lineages and 3 % (1/31) Gamma-variant; wave-2 (December-2020 to May-2021), 25 % (4/16) Alpha-variant, 25 % (4/16) Beta-variant, 44 % (7/16) wild-type and 6 % (1/16) mu; wave-3 (June-October 2021), 94 % (27/29) Delta-variant, 3 % (1/29) Alpha-variant, 3 % (1/29) wild-type; wave-4 (November-2021 to August-2022), 98 % (53/54) Omicron-variant and 2 % (1/54) Delta-variant. Omicron sub-variants were BA.1 (47 %), BA.5 (34 %), BA.2 (13 %) and BA.4 (6 %). Globally, the two genotyping methods accurately identified the SARS-CoV-2 VOCs (P = 0.17, McNemar test; Ka = 0.67). Conclusion: Genomic surveillance reveals a rapid dynamic in SARS-CoV-2 strains between epidemiological waves in Cameroon. For wide-spread variant surveillance in resource-limited settings, SNPsig® SARS-CoV-2 EscapePLEX CEkit represents a suitable tool, pending upgrading for distinguishing Omicron sub-lineages.

Challenges faced by the HIV testing system in low- and middle-income countries.

Introduction: Determining the HIV status of some individuals remains challenging due to multidimensional factors such as flaws in diagnostic systems, technological challenges, and viral diversity. This report pinpoints challenges faced by the HIV testing system in Cameroon. Case presentation: A 53-year-old male received a positive HIV result by a rapid testing algorithm in July 2016. Not convinced of his HIV status, he requested additional tests. In February 2017, he received a positive result using ImmunoComb® II HIV 1 & 2 BiSpot and Roche cobas electrochemiluminescence assays. A sample sent to France in April 2017 was positive on the Bio-Rad GenScreen™ HIV 1/2, but serotyping was indeterminate, and viral load was < 20 copies/mL. The Roche electrochemiluminescence immunoassay and INNO-LIA HIV I/II Score were negative for samples collected in 2018. A sample collected in July 2019 and tested with VIDAS® HIV Duo Ultra enzyme-linked fluorescent assay and Geenius™ HIV 1/2 Confirmatory Assay was positive, but negative with Western blot; CD4 count was 1380 cells/mm3 and HIV proviral DNA tested in France was 'target-not-detected'. Some rapid tests were still positive in 2020 and 2021. Serotyping remained indeterminate, and viral load was 'target-not-detected'. There were no self-reported exposure to HIV risk factors, and his wife was HIV-seronegative. Management and outcome: Given that the patient remained asymptomatic with no evidence of viral replication, no antiretroviral therapy was initiated. Conclusion: This case highlights the struggles faced by some individuals in confirming their HIV status and the need to update existing technologies and develop an algorithm for managing exceptional cases.

High concordance in SARSCoV-2 detection between automated (Abbott m2000) and manual (DaAn gene) RT-PCR systems: The EDCTP PERFECT-Study in Cameroon.

Molecular diagnosis of COVID-19 is critical to the control of the pandemic, which is a major threat to global health. Several molecular tests have been validated by WHO, but would require operational evaluation in the field to ensure their interoperability in diagnosis. In order to ensure field interoperability in molecular assays for detection of SARS-CoV-2 RNA, we evaluated the diagnostic concordance of SARS-CoV-2 between an automated (Abbott) and a manual (DaAn gene) realtime PCR (rRT-PCR), two commonly used assays in Africa. A comparative study was conducted on 287 nasopharyngeal specimens at the Chantal BIYA International Reference Centre (CIRCB) in Yaounde- Cameroon. Samples were tested in parallel with Abbott and DaAn gene rRT-PCR, and performance characteristics were evaluated by Cohen's coefficient and Spearman's correlation. A total of 273 participants [median age (IQR) 36 (26-46) years] and 14 EQA specimens were included in the study. Positivity was on 30.0% (86/287) Abbott and 37.6% (108/287) DaAn gene. Overall agreement was 82.6% (237/287), with k=0.82 (95%CI: 0.777-0.863), indicating an excellent diagnostic agreement. The positive and negative agreement was 66.67% (72/108) and 92.18 % (165/179) respectively. Regarding Viral Load (VL), positive agreement was 100% for samples with high VLs (CT<20). Among positive SARS-CoV- 2 cases, the mean difference in Cycle Threshold (CT) for the manual and Cycle Number (CN) for the automated was 6.75±0.3. The excellent agreement (>80%) between the Abbott and DaAn gene rRTPCR platforms supports interoperability between the two assays. Discordance occurs at low-VL, thus underscoring these tools as efficient weapons in limiting SARS-CoV-2 community transmission.