Centre Pasteur du Cameroun

The omicron lineage has been declared the fifth variant of concern (VOC) by the World Health Organization (WHO). This study aims to describe the genomic characteristics of omicron sequences from Cameroon and to discuss the potential implications of identified mutations for viral evolution and immune escape, based on existing literature. This study is a retrospective analysis of publicly available SARS-CoV-2 sequences from Cameroon submitted to GISAID (Global Initiative on Sharing Avian Influenza Data). Full-length omicron sequences from across Cameroon were retrieved from the GISAID database. Phylogenetic analyses were conducted using Nextstrain SARS-CoV-2 Workflow version 8.2.0, and mutation analysis was performed using the Nextstrain web tool, with the Wuhan-Hu-1/2019 strain as a reference. A total of 1,428 omicron sequences were analyzed, revealing eleven variants: BA.1 lineage (45.0%), B.1.1.529 (0.2%), BA.2 (7.7%), BA.4 (6.5%), BA.5 (16.3%), BE (12.2%), BF (6.3%), BN.2 (0.1%), BQ.1 (3.7%), XBB (0.5%) and JN.1 (1.5%). The sequences exhibited high number of mutations in the spike gene, with the JN.1 lineage showing the highest mutation count. All lineages contained mutations associated with neutralizing antibody evasion, including R346T, K417N, G446S, E484A, or Q493R. Ongoing monitoring of omicron lineages is crucial to detect emerging variants and adapt vaccine strategies. The significant mutations, particularly in the JN.1 lineage warrant further investigation to assess their potential impact on transmissibility or immune escape. Not applicable.

Tumor microenvironment (TME) plays a particularly important role in the pathogenesis and drug resistance of lung cancer. This article provides a framework that allows us to view lung cancer through the lens of cancer stem cells (CSCs) and angiogenesis, with the aim of enhancing both clinical and laboratory insights. It critically examines the bidirectional interactions between CSCs and other components of the TME, highlighting their combined contributions to tumor aggressiveness and angiogenic processes. We discuss the mechanisms by which CSCs influence angiogenesis, including the release of growth factors and cytokines, while also emphasizing how angiogenic factors, in turn, modulate CSC behavior and help maintain a microenvironment that supports tumor growth. Potential biomarkers and therapeutic targets- such as CD133, ALDH1, and VEGF-are explored as valuable not only for disease management but also for the development of targeted therapies for lung cancer. This article ultimately provides a foundation for researchers to further investigate these interconnected processes and for clinicians to consider therapeutic strategies when managing patients with lung cancer. Given the multifaceted nature of lung cancer biology and the numerous molecules involved, we advocate for a panel-centered approach in both research and clinical management, while underscoring the importance of carefully considering toxicity risks and variability in molecular expression.

Long-lasting insecticidal nets (LLINs) are crucial for malaria prevention in Cameroon, yet their operational performance may be compromised because of deterioration of the physical integrity and bioefficacy of nets. This study evaluated LLINs, physical integrity, and bioefficacy following mass distribution campaigns in two regions in Cameroon: East (Bertoua) and Centre (Eyang). Household surveys were conducted to assess ITN ownership, usage patterns, and maintenance practices. Net condition was measured using the proportionate hole index (pHI), and bio-efficacy was assessed using WHO cone bioassays against Anopheles gambiae (s.s.) (Kisumu strain) and local field mosquitoes. A total of 55 LLINs from Bertoua and 30 from Eyang were sampled. LLIN ownership was comparable between sites (66.7% in Bertoua vs. 67.9% in Eyang), with a higher usage rate in Bertoua (73.3%) compared to 58.2% in Eyang. In Bertoua, a large percentage of LLINs (59.6%) were too torn, with Olyset Plus being the most common brand. In contrast, Eyang had a lower proportion of torn nets (44%), and households used a combination of different brands, including the Olyset net, Permanet 2.0, and Royal Sentry. Against the susceptible Kisumu strain, Bertoua's Olyset Plus nets showed optimal efficacy with a 94.6% mortality rate, exceeding the World Health Organization's (WHO) threshold of ≥ 80%. In contrast, nets from Eyang had a 79.3% mortality rate, falling short of the optimal threshold. However, when tested against local field mosquitoes, Olyset Plus (pyrethroid + PBO) showed higher efficacy (mortality rate of 31.8%) than the other brands (7.1% from Olyset net; 18.6% for Permanet 2.0; and 8.6% for Royal Sentry) (p > 0.0001). These findings underscore the crucial importance of proper LLINs maintenance, particularly regarding washing practices. The results also indicate the need to deploy newer generation LLINs to address emerging insecticide resistance and strengthen malaria control efforts.

Hepatitis E virus (HEV) is an important public health concern, especially in developing countries. Complete genomes of HEV strains circulating in Cameroon are not available. Here, we report five nearly complete strains of HEV in Cameroon. These strains share a high identity with human African and swine Asian isolates.

Objectives. Vibrio cholerae remains a significant public health threat in Africa, with antimicrobial resistance (AMR) complicating treatment. This study leverages whole-genome sequencing (WGS) of V. cholerae isolates from Côte d'Ivoire, Ghana, Zambia and South Africa to assess genomic diversity, AMR profiles and virulence, demonstrating the utility of WGS for enhanced surveillance within the PulseNet Africa network.Methods. We analysed Vibrio isolates from clinical and environmental sources (2010-2024) using Oxford Nanopore sequencing and hybracter assembly. Phylogenetic analysis, MLST, virulence and AMR gene detection were performed using Terra, Pathogenwatch and Cloud Infrastructure for Microbial Bioinformatics platforms, with comparisons against 118 global reference genomes for broader genomic context.Results. Of 79 high-quality assemblies, 67 were confirmed as V. cholerae, with serogroup O1 accounting for the majority (43 out of 67, 67%). ST69 accounted for 60% (40 out of 67) of isolates, with 8 sequence types identified overall. Thirty-seven isolates formed distinct sub-clades within AFR12 and AFR15 O1 lineages, suggesting local clonal expansions. AMR gene analysis revealed genes associated with resistance to trimethoprim in 96% of isolates and genes associated with resistance to quinolones in 83%, while genes associated with resistance to azithromycin, rifampicin and tetracycline remained low (≤7%). A significant proportion of the serogroup O1 isolates (41 out of 43, 95%) harboured resistance genes in at least 3 antibiotic classes.Conclusions. This study highlights significant genetic diversity and AMR prevalence in African V. cholerae isolates, with expanding AFR12 and AFR15 clades in the region. The widespread presence of genes associated with resistance to trimethoprim and quinolones raises concerns for treatment efficacy, although azithromycin and tetracycline remain viable options. WGS enables precise identification of species and genotyping, reinforcing PulseNet Africa's pivotal role in advancing genomic surveillance and enabling timely public health responses to cholera outbreaks.

IntroductionCameroon faced several waves of COVID-19 epidemics between 2020 and 2022. The epidemic peaks were characterized by variations in the number of positive cases and major variants. The aim of this study was to determine the frequency of COVID-19 in Cameroon during the different epidemic waves.Methodsnasopharyngeal samples were collected in different regions of Cameroon between 2020 and 2022. The Daan Gene kit (DaAn Gene, Guangzhou, Guangdong Province, China) was used to detect SARS-CoV-2 in the samples by RT-PCR assay. Excel 2013 software was used to record participants´ sociodemographic characteristics (age, sex, sampling date) and SARS-CoV-2 test results. Statistical analyses were performed using IBM SPSS version 25 software.Resultsfrom 16 March 2020 to 31 December 2022, 142,850 samples were tested. Participants ranged in age from 1 to 99 years with a M/F sex ratio of 1.32. Of the participants tested, 17,463 (12.2%) were positive for SARS-CoV-2. The SARS-CoV-2 detection rate decreased over time and was highest in 2020 (15.6%; 7255/46466) as opposed to 2021 (12.7%; 8859/69867) and 2022 (5.1%; 1349/26383). Four peaks of COVID-19 circulation were identified: May 2020, March 2021, September 2021 and December 2021. Risk factors for increased detection of SARS-CoV-2 were being older than 65 years and being from the Littoral region.Conclusionthe SARS-CoV-2 positivity rate in Cameroon decreased over the years, probably due to compliance with the barrier measures implemented by the Cameroonian government to reduce transmission rates.

ABSTRACT Recent evidence of vertical transmission of Tonate virus (TONV) during early pregnancy and its association with fetal neurological anomalies highlights its potential public health threat. TONV is an understudied alphavirus endemic to French Guiana. The growing presence of Aedes (Ae.) albopictus in Europe raises concerns about its ability to transmit emerging arboviruses, including TONV. We assessed the vector competence of Ae. albopictus populations from mainland France and La Réunion Island via oral infections using different TONV doses. Both populations supported efficient viral replication, with infectious viral particles appearing in saliva by day 5 post-infection. Infection rate (IR), stepwise dissemination rate (sDR), and transmission efficiency (TE) increased with rising viral concentrations. At a viral concentration of 106 PFU/mL IR reached 80%, and TE at day 5 post-infection was 27% for the mainland strain and 37% for the La Réunion strain. Notably, TE declined over time in the mainland strain, while increasing progressively in the La Réunion population. Comparative infections with Chikungunya virus revealed that TONV was transmitted at similar or greater rates, confirming Ae. albopictus as a competent vector. Sequencing of mosquito organs revealed intra-host TONV genetic variability. A recurrent polymorphism at position 11,357 in the 3′UTR was detected in body tissues but not in heads of La Réunion mosquitoes, suggesting tissue-specific selection or bottlenecks. Our results demonstrate that Ae. albopictus from both tropical and temperate areas can efficiently transmit TONV and emphasize the importance of genomic surveillance to anticipate risk of its emergence in areas where this vector is established.

Introduction: Despite progress over the last decade, uptake of family planning services remains a challenge in Zambia. Interventions delivered by mobile phone could help increase uptake and continuation of contraception, particularly among hard-to-reach populations. The aim of this study was to investigate willingness of women of reproductive age to using a mobile based application to improve uptake to family planning services in selected communities of Zambia. Methods: A cross-sectional study was conducted in two selected communities of Mumbwa district between October-November 2021. Community Health Volunteers were responsible for mapping households within the catchment areas and administering survey questionnaires. Descriptive statistics were calculated for dichotomous and categorical variables. To assess associations between categorical variables, Chi-square tests were performed. All data analyses were carried out using STATA version 14.2. Results: A total of 449 participants were surveyed, from Bulungu Urban Health Centre (UHC) and Najanjoli Rural Health Centre (RHC). Most participants were between 15 and 24 years (42.54%). Only 2.46% of participants reported no formal education, with the majority having attained a secondary school level of education (52.13%). Half of households (51.70%) possessed phones, among which only 30% (126/440) were smartphones. Furthermore, 83.41% (367/450) were willing to receive family planning messages via phones. A much higher proportion of unemployed participants (73.02%; P<005), those who accessed services from Bulungu UHC (60.33%: p<005) and married women (83.65%: p<005) were willing to receive planning messages on phones. Conclusion: This study demonstrates strong willingness to use digital application to increase awareness and enhance uptake of family planning services amongst women of reproductive age in rural settings of Zambia. These findings support the feasibility of implementing digital/phone-based strategies in community health systems to increase access to health care. Further research is needed to design and evaluate scalable mobile health solutions tailored to the local context.