Browsing by Author "Prah, D.A."
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Item Reduced transmission of Mycobacterium africanum compared to Mycobacterium tuberculosis in urban West Africa(International Journal of Infectious Diseases, 2018-08) Asare, P.; Asante-Poku, A.; Prah, D.A.; Borrell, S.; Osei-Wusu, S.; Otchere, I.D.; Forson, A.; Adjapong, G.; Koram, K.A.; Gagneux, S.; Yeboah-Manu, D.Objective: Understanding transmission dynamics is useful for tuberculosis (TB) control. A population-based molecular epidemiological study was conducted to determine TB transmission in Ghana. Methods: Mycobacterium tuberculosis complex (MTBC) isolates obtained from prospectively sampled pulmonary TB patients between July 2012 and December 2015 were characterized using spoligotyping and standard 15-locus mycobacterial interspersed repetitive unit variable number tandem repeat (MIRU-VNTR) typing for transmission studies. Results: Out of 2309 MTBC isolates, 1082 (46.9%) unique cases were identified, with 1227 (53.1%) isolates belonging to one of 276 clusters. The recent TB transmission rate was estimated to be 41.2%. Whereas TB strains of lineage 4 belonging to M. tuberculosis showed a high recent transmission rate (44.9%), reduced recent transmission rates were found for lineages of Mycobacterium africanum (lineage 5, 31.8%; lineage 6, 24.7%). Conclusions: The study findings indicate high recent TB transmission, suggesting the occurrence of unsuspected outbreaks in Ghana. The observed reduced transmission rate of M. africanum suggests other factor(s) (host/environmental) may be responsible for its continuous presence in West Africa. © 2018 The Author(s)Item Sensitive Detection of Asymptomatic and Symptomatic Malaria with Seven Novel Parasite-Specific LAMP Assays and Translation for Use at Point-of-Care(Microbiology Spectrum, 2023) Malpartida-Cardenas, K.; Moser, N.; Ansah, F.; Pennisi, I.; Prah, D.A.; Amoah, L.E.; Awandare, G.; Hafalla, J.C.R.; Cunnington, A.; Baum, J.; Rodriguez-Manzano, J.; Georgiou, P.Human malaria is a life-threatening parasitic disease with high impact in the sub-Saharan Africa region, where 95% of global cases occurred in 2021. While most malaria diagnostic tools are focused on Plasmodium falciparum, there is a current lack of testing non-P. falciparum cases, which may be underreported and, if undiagnosed or untreated, may lead to severe consequences. In this work, seven species-specific loop-mediated isothermal amplification (LAMP) assays were designed and evaluated against TaqMan quan titative PCR (qPCR), microscopy, and enzyme-linked immunosorbent assays (ELISAs). Their clinical performance was assessed with a cohort of 164 samples of symptomatic and asymptomatic patients from Ghana. All asymptomatic samples with a parasite load above 80 genomic DNA (gDNA) copies per mL of extracted sample were detected with the Plasmodium falciparum LAMP assay, reporting 95.6% (95% confidence interval [95% CI] of 89.9 to 98.5) sensitivity and 100% (95% CI of 87.2 to 100) specificity. This assay showed higher sensitivity than microscopy and ELISA, which were 52.7% (95% CI of 39.7 to 67%) and 67.3% (95% CI of 53.3 to 79.3%), respectively. Nine samples were posi tive for P. malariae, indicating coinfections with P. falciparum, which represented 5.5% of the tested population. No samples were detected as positive for P. vivax, P. ovale, P. knowl esi, or P. cynomolgi by any method. Furthermore, translation to the point-of-care was demonstrated with a subcohort of 18 samples tested locally in Ghana using our hand held lab-on-chip platform, Lacewing, showing comparable results to a conventional fluo rescence-based instrument. The developed molecular diagnostic test could detect asymp tomatic malaria cases, including submicroscopic parasitemia, and it has the potential to be used for point-of-care applicationsItem Whole Genome Sequencing and Spatial Analysis Identifies Recent Tuberculosis Transmission Hotspots in Ghana(Frontiers in Medicine, 2020-05-19) Asare, P.; Otchere, I.D.; Bedeley, E.; Brites, D.; Loiseau, C.; Baddoo, N.A.; Asante-Poku, A.; Osei-Wusu, S.; Prah, D.A.; Borrell, S.; Reinhard, M.; Forson, A.; Koram, K.A.; Gagneux, S.; Yeboah-Manu, D.Whole genome sequencing (WGS) is progressively being used to investigate the transmission dynamics of Mycobacterium tuberculosis complex (MTBC). We used WGS analysis to resolve traditional genotype clusters and explored the spatial distribution of confirmed recent transmission clusters. Bacterial genomes from a total of 452 MTBC isolates belonging to large traditional clusters from a population-based study spanning July 2012 and December 2015 were obtained through short read next-generation sequencing using the illumina HiSeq2500 platform. We performed clustering and spatial analysis using specified R packages and ArcGIS. Of the 452 traditional genotype clustered genomes, 314 (69.5%) were confirmed clusters with a median cluster size of 7.5 genomes and an interquartile range of 4–12. Recent tuberculosis (TB) transmission was estimated as 24.7%. We confirmed the wide spread of a Cameroon sub-lineage clone with a cluster size of 78 genomes predominantly from the Ablekuma sub-district of Accra metropolis. More importantly, we identified a recent transmission cluster associated with isoniazid resistance belonging to the Ghana sub-lineage of lineage 4. WGS was useful in detecting unsuspected outbreaks; hence, we recommend its use not only as a research tool but as a surveillance tool to aid in providing the necessary guided steps to track, monitor, and control TB.