BACKGROUND:We aimed to establish an external quality assessment (EQA) programme for the yaws eradication campaign that would meet the needs of reference and district-level laboratories in low- and middle-income countries. METHODOLOGY/PRINCIPAL FINDINGS:We designed proficiency testing items (PTIs) using a plasmid containing gene target sequences for Treponema pallidum (TP) and Haemophilus ducreyi (HD). The storage stability of the plasmids under different environmental conditions was then tested. A proficiency testing panel of seven swabs loaded with different concentrations of plasmids in different combinations, as well as human HEK293 cells to simulate the sample background, was prepared and sent to participating reference (RL) and district (DL) laboratories in Ghana, Côte d'Ivoire and Cameroon followed by three rounds of blinded proficiency testing. We tested quantitative real-time PCR (qPCR) performance of reference laboratories and loop-mediated isothermal amplification (LAMP) performance of district laboratories and retested 20% of human field samples at the London School of Hygiene & Tropical Medicine laboratories to further assess qPCR quality. FINDINGS:PTIs proved to be stable in dry conditions with no significant loss of copy number. Participating laboratories achieved qPCR results with a concordance of 95.0-100.0% (97.7% ± 5.2% (mean±standard deviation ((SD)) with the provider and a concordance of 76.0-100.0% (TP: 90.3 ± 13.7% and HD: 78.5 ± 7.5% (mean±SD)) for LAMP results, with inconsistencies, particularly in the detection of low HD plasmid DNA levels combined with high TP plasmid copies. Retesting of field samples resulted in 100% correct TP and HD sample identification by the African reference laboratories. CONCLUSIONS/SIGNIFICANCE:We have developed a functional plasmid-based EQA programme specifically designed to meet the needs of resource-poor settings in the tropics. The programme is suitable as a blueprint for other disease programmes.
Men engaged in transactional sex (METS) represent a neglected key population in sub-Saharan Africa (SSA), yet little is known about their burden of sexually transmitted infections (STIs) and associated factors. This study assessed the prevalence of self-reported STIs (SR-STI) and identified individual, community, and country-level determinants among this group. We analyzed pooled recent nationally representative Demographic and Health Survey (DHS) data from 26 SSA countries. This study included 10,128 men who reported engagement in transactional sex within the past 12 months. Weighted prevalence estimates were calculated, and multilevel logistic regression models were applied to examine individual-, community-, and country-level determinants of SR-STI symptoms, adjusting for survey year. AIC and BIC were used as comparative model selection criteria to identify the best-fitting model among the sequential multilevel models built. The participants’ mean (± SD) age was 29.8 (± 10.2) years. The overall weighted prevalence of SR-STIs among METS was 19.5
INTRODUCTION:The Biological Sample Management Platform (PGEB) of the Centre Léon Bérard is responsible for the preparation, preservation, storage, and provision of the institution's sample collection. The PGEB was approached to integrate a neuroblastoma collection, one of the most common pediatric cancers. This collection was initiated through the diagnostic reference activity for neuroblastoma at the Centre Léon Bérard. OBJECTIVES:To requalify pediatric biological samples collected between 1984 and 2024 and to make them available for pediatric research protocols. METHODS:This study began with an assessment of the data associated with each of the 21,389 samples in the collection. These data were then compared with relevant regulations and consensus documents related to biobank data management, as well as the minimum data requirements for research use. Based on this, a methodology for sorting samples-either for retention or disposal-was applied. RESULTS:A set of minimum information criteria was established to revalue the samples. Various texts applicable in France mention the minimum data required for making samples available, but no consensus exists, either nationally or internationally. Furthermore, 65% of the samples met the criteria and were retained for future research use. CONCLUSIONS:This article describes the research work that led to the identification of minimum required data. However, further development is needed to harmonize practices regarding data management and interoperability.
Naturally acquired immunity to Plasmodium falciparum involves parasite-specific antibodies as well as autoreactive responses that may contribute to immune regulation and tolerance. Characterizing these antibody repertoires across clinical phenotypes and transmission settings may help distinguish asymptomatic carriage from clinical malaria and identify biomarkers of exposure and protection. We conducted a cross-sectional study in three malaria-endemic settings in Côte d’Ivoire (Korhogo, Man, and Abobo). Individuals with mild malaria (MM; n = 94) were enrolled across all three sites, whereas asymptomatic carriers (AS; n = 33) and endemic controls (EC; n = 39) were enrolled in Abobo only. Total IgG responses to P. falciparum (3D7 whole-parasite extract), self-antigens (human brain extract), and mosquito exposure (gSG6-P1) were measured by ELISA or Luminex. The breadth and specificity of autoreactive IgGs were assessed by PANAMA blotting followed by mass spectrometry. Multivariate analyses were used to identify antigenic signatures associated with clinical phenotype and, among MM individuals, differences in transmission intensity. Compared with MM, AS individuals exhibited lower total IgG reactivity to P. falciparum antigens but higher levels of autoreactive IgG3 with a broader antigenic repertoire. Proteomic analysis identified γ- and β-actin, as well as several metabolic enzymes (including succinate-CoA ligase, acetyl-CoA acyltransferase 2, acyl-CoA dehydrogenase, and glutaryl-CoA dehydrogenase) as targets distinguishing AS and EC from MM. Among MM cases, a cluster of brain antigens in the 50–75 kDa range differentiated sites with distinct transmission intensities. IgG responses to gSG6-P1 correlated with autoreactive IgG levels, suggesting an association between mosquito exposure and autoreactive immune responses. Asymptomatic P. falciparum infection in a high-transmission setting was associated with enhanced autoreactive IgG3 responses, a profile that may reflect clinical tolerance and cumulative exposure. Autoreactive antibody signatures, together with markers of mosquito exposure, may serve as candidate biomarkers of malaria exposure and naturally acquired immunity and could inform surveillance and control strategies in endemic areas.
Togo experienced its first nationally reported dengue outbreak in 2024 amid a broader resurgence of dengue across Africa. Data on serotype distribution, genomic diversity, and transmission dynamics in the region were limited. Here, we integrated epidemiological, genomic, and environmental analyses to characterize the origins and spread of dengue transmission in Togo. Of 475 samples tested, 213 (44.8%) were dengue virus (DENV) positive by PCR. Of these, 190 samples (Ct < 35) were serotyped and 159 of those successfully serotyped underwent whole-genome sequencing. Sequencing generated one DENV-3 genome and 129 DENV-1 genomes, predominantly of genotype III lineage A.2. Our phylogenetic results suggest importation of this lineage from Tanzania into West Africa and Togo, linked to a large Tanzanian outbreak in 2019. Time-scaled phylogenies indicated the timing of introduction likely goes back early 2020, with cryptic circulation preceding the detected outbreak. Bayesian phylogeographic reconstruction support the inference of one common introduction into Togo/West-Africa and identified short- and long-range viral movements nationally and regionally. We conclude that 2024 dengue epidemic in Togo resulted from a single introduction followed by extensive local and regional spread facilitated by favourable environmental conditions and human mobility. In addition, this study doubles the number of available West African DENV-1-III A.2 genomes and highlights significant gaps in regional genomic surveillance that present challenges in understanding transmission pathways. Integrated, high-resolution genomic and epidemiological monitoring for dengue is essential for national and regional preparedness, readiness and response.
