Research Articles
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A research article reports the results of original research, assesses its contribution to the body of knowledge in a given area, and is published in a peer-reviewed scholarly journal. The faculty publications through published and on-going articles/researches are captured in this community
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Item Nutritional and cognitive deficits of school-age children: A study in helminth-endemic fishing and farming communities in Ghana(Nutrition & Food Science, 2019-08-22) Wilson, M.D.; Tandoh, M.A.; Mills-Robertson, F.C.; Anderson, A.K.Purpose – The purpose of this study was to elucidate the association between helminth infections, dietary parameters and cognitive performance, as well as the predictors of undernutrition among school-age children (SAC) living in helminth-endemic fishing and farming communities in Ghana. Design/methodology/approach – This was a cross sectional study involving 164 (9 to 12 years old) SAC from fishing (n=84) and farming (n=80) communities of the Kwahu Afram Plains South District of the Eastern Region of Ghana, using structured questionnaires and anthropometric and biochemical assessments. Findings – Overall, 51.2% of the children were males, with no significant gender difference between the communities (p=0.88). Average age of the children was 10.561.25 years, with no significant difference between the farming and fishing communities (p=0.90). About 53.1% of all children were anemic, with no significant differences between farming versus fishing communities (p=0.87). Helminth-infected children were significantly anemic (p=0.03). Mean serum zinc level of all children was 13.164.57mmol/L, with zinc deficiency being significantly higher in children in the farming community (p<0.0001). About 7.5%of all the children were underweight, whilst 13.8% were stunted with a higher proportion of stunting occurring among older children (p=0.001) and girls (p=0.117). There was no significant difference in the Raven’s Colored Progressive Matrices cognitive test scores between the two communities (p=0.79). Predictors of anemia were helminthiasis and pica behavior. Originality/value – These findings are relevant and have the prospect of guiding the development of intervention programs in addressing the persistent problem of nutritional and cognitive deficits among SAC.Item Molecular Informatics Studies of the Iron-Dependent Regulator (ideR) Reveal Potential Novel Anti-Mycobacterium ulcerans Natural Product-Derived Compounds(Molecules, 2019-06-21) Kwofie, S.K.; Enninful, K.S.; Yussif, J.A.; Asante, L.A.; Adjei, M.; Kan-Dapaah, K.; Tiburu, E.K.; Mensah, W.A.; Miller, W.A.III.; Mosi, L.; Wilson, M.D.Buruli ulcer is a neglected tropical disease caused by the bacterium Mycobacterium ulcerans. Its virulence is attributed to the dermo-necrotic polyketide toxin mycolactone, whose synthesis is regressed when its iron acquisition system regulated by the iron-dependent regulator (ideR) is deactivated. Interfering with the activation mechanism of ideR to inhibit the toxin’s synthesis could serve as a possible cure for Buruli ulcer. The three-dimensional structure of the ideR for Mycobacterium ulcerans was generated using homology modeling. A library of 832 African natural products (AfroDB), as well as five known anti-mycobacterial compounds were docked against the metal binding site of the ideR. The area under the curve (AUC) values greater than 0.7 were obtained for the computed Receiver Operating Characteristics (ROC) curves, validating the docking protocol. The identified top hits were pharmacologically profiled using Absorption, Distribution, Metabolism, Elimination and Toxicity (ADMET) predictions and their binding mechanisms were characterized. Four compounds with ZINC IDs ZINC000018185774, ZINC000095485921, ZINC000014417338 and ZINC000005357841 emerged as leads with binding energies of −7.7 kcal/mol, −7.6 kcal/mol, −8.0 kcal/mol and −7.4 kcal/mol, respectively. Induced Fit Docking (IFD) was also performed to account for the protein’s flexibility upon ligand binding and to estimate the best plausible conformation of the complexes. Results obtained from the IFD were consistent with that of the molecular docking with the lead compounds forming interactions with known essential residues and some novel critical residues Thr14, Arg33 and Asp17. A hundred nanoseconds molecular dynamic simulations of the unbound ideR and its complexes with the respective lead compounds revealed changes in the ideR’s conformations induced by ZINC000018185774. Comparison of the lead compounds to reported potent inhibitors by docking them against the DNA-binding domain of the protein also showed the lead compounds to have very close binding affinities to those of the potent inhibitors. Interestingly, structurally similar compounds to ZINC000018185774 and ZINC000014417338, as well as analogues of ZINC000095485921, including quercetin are reported to possess anti-mycobacterial activity. Also, ZINC000005357841 was predicted to possess anti-inflammatory and anti-oxidative activities, which are relevant in Buruli ulcer and iron acquisition mechanisms, respectively. The leads are molecular templates which may serve as essential scaffolds for the design of future anti-mycobacterium ulcerans agents.Item Levels of serum eosinophil cationic protein are associated with hookworm infection and intensity in endemic communities in Ghana(Plos One, 2019-09-12) Amoani, B.; Adu, B.; Frempong, M.T.; Sarkodie-Addo, T.; Nuvor, S.V.; Wilson, M.D.; Gyan, B.Background The eosinophil cationic protein (ECP) is a cytotoxic protein mainly secreted by eosinophils granulocytes and plays a role in host defense against parasitic infections. Infection with Necator americanus (hookworm) is traditionally diagnosed by the Kato-Katz method which is inherently tedious, subjective and known to underestimate infection intensity. This study aimed to assess levels of serum ECP in relation to hookworm infection intensity. Methods Stool samples from 984 (aged 4 to 80 years) participants in a cross-sectional study conducted in the Kintampo North Municipality of Ghana were examined using the Kato-Katz and formol-ether concentration methods. Serum ECP levels were measured by ECP assay kit and compared between 40 individuals infected with hookworm only, 63 with hookworm- Plasmodium falciparum co-infection, 59 with P. falciparum infection and 36 with no infection. Results Hookworm infection prevalence was 18.1% (178/984). ECP levels were significantly higher in individuals infected with hookworm only (β = 2.96, 95%CI = 2.69, 3.23, p<0.001) or co-infected with P. falciparum (β = 3.15, 95%CI = 2.91, 3.39, p<0.001) compared to the negative control. Levels of ECP were similar between those with only P. falciparum infection and the uninfected control (p>0.05). Increased hookworm intensity was associated with a significant increase in ECP level (β = 4.45, 95%CI = 2.25, 9.11, rs = 0.193, n = 103, p<0.01). ECP threshold of 84.98ng/ml was associated with a positive predictive value (PPV) of 98% (95% CI = 92, 100), and negative predictive value (NPV) of 76% (95% CI = 62, 87) in classifying hookworm infection status with an AUROC of 96.3%. Conclusion Serum ECP level may be a good biomarker of hookworm infection and intensity and warrant further investigations to help improve current hookworm diagnosis.Item Cytokine profiles of Necator americanus and Plasmodium falciparum coinfected patients in rural Ghana(Cytokine: X, 2019-10-04) Adu, B.; Amoani, B.; Frempong, M.T.; Sarkodie-Addo, T.; Nuvor, S,.V.; Abu, E.K.; Harrison, L.M.; Cappello, M.; Gyan, B.; Wilson, M.D.Background: Necator americanus (hookworm) and Plasmodium falciparum co-infections are common in endemic communities in rural Ghana. Human immune responses to P. falciparum and hookworm are complex, and the dynamics of cytokine levels and effector mediators are poorly understood. This study aimed to determine the effect of hookworm and P. falciparum co-infection on parasite intensities and cytokine profiles in individuals before and after deworming drug treatment. Methods: In this cross-sectional study conducted in the Kintampo North Municipality of Ghana blood and stool samples were analyzed from 984 participants (aged 4–88 years). Stool samples were collected at baseline from all participants and examined for the presence of hookworm using the Kato-Katz method. Blood and stool samples were analysed again two weeks after albendazole treatment of hookworm infected individuals. Malaria parasitaemia was estimated by light microscopy and P. falciparum-specific 18S rRNA gene PCR method used for species identification. Serum levels of circulating cytokines interleukins -5, -10 (IL-5, IL-10), tumor necrosis factor [TNF]-α, and eotaxin [CCL11] were determined using ELISA based methods. Results: Malaria parasitaemia was significantly reduced in hookworm and P. falciparum co-infected individuals (p=0.0018) while hookworm intensity was similar between groups. IL-10 level was significantly higher in the co-infected individuals (39.9 ± 12.2 pg/ml) compared to the single infected or the uninfected group (10.7 ± 7.6 mg/ml). IL-5 level was higher in the hookworm only infected individual. TNF-α levels were higher in all infected groups compared to the uninfected controls. CCL11 levels were significantly higher in subjects infected with hookworm only or co-infected with hookworm and P. falciparum. There was a significantly negative correlation (rs=−0.39, p=0.021) between hookworm eggs per gram of stool and CCL11 levels in the group mono-infected with hookworm which was not affected by treatment. Treatment with albendazole led to a significant reduction of TNF-α (p=0.041), IL-5 (p=0.01) and IL-10 (p=0.001) levels. Conclusion: This study shows that in the absence of other helminths, co-infection of hookworm with P. falciparum may modulate blood parasitemia levels and cytokine responses. Data also show that deworming drug treatment alters these cytokine profiles in hookworm infected subjects. Future studies to elucidate the potential mechanisms underlying these observations should include an assessment of parasite specific cellular responsesItem Assessing the Presence of Wuchereria bancrofti Infections in Vectors Using Xenomonitoring in Lymphatic Filariasis Endemic Districts in Ghana(Tropical Medicine and Infectious Disease, 2019-03-13) Dadzie, S.K.; Pi-Bansa, S.; Osei, J.H.N.; Kartey-Attipoe, W.D.; Elhassan, E.; Agyemang, D.; Otoo, S.; Appawu, M.A.; Wilson, M.D.; Koudou, B.G.; De Souza, D.K.; Utzinger, J.; Boakye, D.A.Mass drug administration (MDA) is the current mainstay to interrupt the transmission of lymphatic filariasis. To monitor whether MDA is effective and transmission of lymphatic filariasis indeed has been interrupted, rigorous surveillance is required. Assessment of transmission by programme managers is usually done via serology. New research suggests that xenomonitoring holds promise for determining the success of lymphatic filariasis interventions. The objective of this study was to assess Wuchereria bancrofti infection in mosquitoes as a post-MDA surveillance tool using xenomonitoring. The study was carried out in four districts of Ghana; Ahanta West, Mpohor, Kassena Nankana West and Bongo. A suite of mosquito sampling methods was employed, including human landing collections, pyrethrum spray catches and window exit traps. Infection of W. bancrofti in mosquitoes was determined using dissection, conventional and real-time polymerase chain reaction and loop mediated isothermal amplification assays. Aedes, Anopheles coustani, An. gambiae, An. pharoensis, Culex and Mansonia mosquitoes were sampled in each of the four study districts. The dissected mosquitoes were positive for filarial infection using molecular assays. Dissected An. melas mosquitoes from Ahanta West district were the only species found positive for filarial parasites. We conclude that whilst samples extracted with Trizol reagent did not show any positives, molecular methods should still be considered for monitoring and surveillance of lymphatic filariasis transmission.Item Pharmacoinformatics-based identification of potential bioactive compounds against Ebola virus protein VP24(Computers in Biology and Medicine, 2019-08-24) Kwofie, S.K.; Broni, E.; Teye, J.; Quansah, E.; Issah, I.; Wilson, M.D.; Miller, W.A.; Tiburu, E.K.; Bonney, J.H.K.Background: The impact of Ebola virus disease (EVD) is devastating with concomitant high fatalities. Currently, various drugs and vaccines are at different stages of development, corroborating the need to identify new therapeutic molecules. The VP24 protein of the Ebola virus (EBOV) plays a key role in the pathology and replication of the EVD. The VP24 protein interferes with the host immune response to viral infections and promotes nucleocapsid formation, thus making it a viable drug target. This study sought to identify putative lead compounds from the African flora with potential to inhibit the activity of the EBOV VP24 protein using pharmacoinformatics and molecular docking. Methods: An integrated library of 7675 natural products originating from Africa obtained from the AfroDB and NANPDB databases, as well as known inhibitors were screened against VP24 (PDB ID: 4M0Q) utilising AutoDock Vina after energy minimization using GROMACS. The top 19 compounds were physicochemically and pharmacologically profiled using ADMET Predictor™, SwissADME and DataWarrior. The mechanisms of binding between the molecules and EBOV VP24 were characterised using LigPlot+. The performance of the molecular docking was evaluated by generating a receiver operating characteristic (ROC) by screening known inhibitors and decoys against EBOV VP24. The prediction of activity spectra for substances (PASS) and machine learning-based Open Bayesian models were used to predict the anti-viral and anti-Ebola activity of the molecules, respectively. Results: Four natural products, namely, ZINC000095486070, ZINC000003594643, ZINC000095486008 and sarcophine were found to be potential EBOV VP24-inhibitiory molecules. The molecular docking results showed that ZINC000095486070 had high binding affinity of −9.7 kcal/mol with EBOV VP24, which was greater than those of the known VP24-inhibitors used as standards in the study including Ouabain, Nilotinib, Clomiphene, Torimefene, Miglustat and BCX4430. The area under the curve of the generated ROC for evaluating the performance of the molecular docking was 0.77, which was considered acceptable. The predicted promising molecules were also validated using induced-fit docking with the receptor using Schrödinger and molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) calculations. The molecules had better binding mechanisms and were pharmacologically profiled to have plausible efficacies, negligible toxicity as well as suitable for designing anti-Ebola scaffolds. ZINC000095486008 and sarcophine (NANPDB135) were predicted to possess antiviral activity, while ZINC000095486070 and ZINC000003594643 to be anti-Ebola compounds. Conclusion: The identified compounds are potential inhibitors worthy of further development as EBOV biotherapeutic agents. The scaffolds of the compounds could also serve as building blocks for designing novel Ebola inhibitors.Item An Evaluation of Wb123 Antibody Elisa in Individuals Treated With Ivermectin and Albendazole, and Implementation Challenges in Africa(Pan African Medical Journal, 2017-05) de Souza, D.K.; Owusu, I.O.; Otchere, J.; Adimazoya, M.; Frempong, K.; Ahorlu, C.S.; Boakye, D.A.; Wilson, M.D.The development of antibody testing for the diagnosis of lymphatic filariasis (LF) is intended to enhance the monitoring and evaluation activities of the Global Program for the Elimination of LF. This is due to the fact that antibody tests are expected to be the most sensitive at detecting exposure to LF compared to antigen that takes longer to develop. To this end a new antibody-based enzyme linked immunosorbent assay (ELISA) to Wuchereria bancrofti antigen Wb123 has been developed and further designed into a point of care rapid diagnostic test, under evaluation. In pre-treatment surveys, individuals were tested for antigen using the immuno-chromatographic test (ICT) card, and night blood microfilariae, after which all positives were treated using Ivermectin and Albendazole. The Wb123 ELISA was tested in antigen positive individuals, three months after they were treated. Samples were also tested for ICT and night blood microfilariae. The results revealed a reduction in microfilariae and ICT prevalence after treatment. Antigen and antibody prevalence increased with age. However, there was no correlation with the antibody responses observed. The mean WB123 antibody titers were higher among ICT positives, but not significantly different from ICT negative persons. While the Wb123 is targeted for use in untreated populations, further evaluations and guidelines will be required to define its use in populations that have undergone treatment for the control of LF.Item The genomic architecture of novel simulium damnosum wolbachia prophage sequence elements and implications for onchocerciasis epidemiology(Frontiers in Microbiology, 2017) Crainey, J.L.; Hurst, J.; Lamberton, P.H.L.; Cheke, R.A.; Griffin, C.E.; Wilson, M.D.; Mendes de Araújo, C.P.; Basáñez, M.-G.; Post, R.J.Research interest in Wolbachia is growing as new discoveries and technical advancements reveal the public health importance of both naturally occurring and artificial infections. Improved understanding of the Wolbachia bacteriophages (WOs) WOcauB2 and WOcauB3 [belonging to a sub-group of four WOs encoding serine recombinases group 1 (sr1WOs)], has enhanced the prospect of novel tools for the genetic manipulation of Wolbachia. The basic biology of sr1WOs, including host range and mode of genomic integration is, however, still poorly understood. Very few sr1WOs have been described, with two such elements putatively resulting from integrations at the same Wolbachia genome loci, about 2 kb downstream from the FtsZ cell-division gene. Here, we characterize the DNA sequence flanking the FtsZ gene of wDam, a genetically distinct line of Wolbachia isolated from the West African onchocerciasis vector Simulium squamosum E. Using Roche 454 shot-gun and Sanger sequencing, we have resolved >32 kb of WO prophage sequence into three contigs representing three distinct prophage elements. Spanning =36 distinct WO open reading frame gene sequences, these prophage elements correspond roughly to three different WO modules: a serine recombinase and replication module (sr1RRM), a head and base-plate module and a tail module. The sr1RRM module contains replication genes and a Holliday junction recombinase and is unique to the sr1 group WOs. In the extreme terminal of the tail module there is a SpvB protein homolog-believed to have insecticidal properties and proposed to have a role in how Wolbachia parasitize their insect hosts. We propose that these wDam prophage modules all derive from a single WO genome, which we have named here sr1WOdamA1. The best-match database sequence for all of our sr1WOdamA1-predicted gene sequences was annotated as of Wolbachia or Wolbachia phage sourced from an arthropod. Clear evidence of exchange between sr1WOdamA1 and other Wolbachia WO phage sequences was also detected. These findings provide insights into how Wolbachia could affect a medically important vector of onchocerciasis, with potential implications for future control methods, as well as supporting the hypothesis that Wolbachia phages do not follow the standard model of phage evolution. © 2017 Crainey, Hurst, Lamberton, Cheke, Griffin, Wilson, de Araújo, Basáñez and Post.Item Genetic Markers of Benzimidazole Resistance among Human Hookworms (Necator americanus) in Kintampo North Municipality, Ghana(American Journal of Tropical Medicine and Hygiene, 2019-02) Orr, A.R.; Quagraine, J.E.; Suwondo, P.; George, S.; Harrison, L.M.; Dornas, F.P.; Evans, B.; Caccone, A.; Humphries, D.; Wilson, M.D.; Cappello, M.Hookworm infection causes anemia, malnutrition, and growth delay, especially in children living in sub-Saharan Africa. The World Health Organization recommends periodic mass drug administration (MDA) of anthelminthics to school-age children (SAC) as a means of reducing morbidity. Recently, questions have been raised about the effectiveness of MDA as a global control strategy for hookworms and other soil-transmitted helminths (STHs). Genomic DNA was extracted from Necator americanus hookworm eggs isolated from SAC enrolled in a cross-sectional study of STH epidemiology and deworming response in Kintampo North Municipality, Ghana. A polymerase chain reaction (PCR) assay was then used to identify single-nucleotide polymorphisms (SNPs) associated with benzimidazole resistance within the N. americanus β-tubulin gene. Both F167Y and F200Y resistance-associated SNPs were detected in hookworm samples from infected study subjects. Furthermore, the ratios of resistant to wild-type SNP at these two loci were increased in posttreatment samples from subjects who were not cured by albendazole, suggesting that deworming drug exposure may enrich resistance-associated mutations. A previously unreported association between F200Y and a third resistance-associated SNP, E198A, was identified by sequencing of F200Y amplicons. These data confirm that markers of benzimidazole resistance are circulating among hookworms in central Ghana, with unknown potential to impact the effectiveness and sustainability of chemotherapeutic approaches to disease transmission and control.Item Evaluating Academic Mentorship Programs in Low- and Middle-Income Country Institutions: Proposed Framework and Metrics(American Journal of Tropical Medicine and Hygiene, 2019-01) Chi, B.H.; Belizan, J.M.; Blas, M.M.; Chuang, A.; Wilson, M.D.; Chibwesha, C.J.; Farquhar, C.; Cohen, C.R.; Raj, T.A growing number of low- and middle-income country (LMIC) institutions have developed and implemented formal programs to support mentorship. Although the individual-level benefits of mentorship are well established, such activities can also sustainably build institutional capacity, bridge inequities in health care, and catalyze scientific advancement. To date, however, evaluation of these programs remains limited, representing an important gap in our understanding about the impact of mentoring. Without rigorous and ongoing evaluation, there may be missed opportunities for identifying best practices, iteratively improving program activities, and demonstrating the returns on investment in mentorship. In this report, we propose a framework for evaluating mentorship programs in LMIC settings where resources may be constrained. We identify six domains: 1) mentor-mentee relationship, 2) career guidance, 3) academic productivity, 4) networking, 5) wellness, and 6) organizational capacity. Within each, we describe specific metrics and how they may be considered as part of evaluation plans. We emphasize the role of measurement and evaluation at the institutional level, so that programs may enhance their mentoring capacity and optimize the management of their resources. Although we advocate for a comprehensive approach to evaluation, we recognize that-depending on stage and relative maturity-some domains may be prioritized to address short- and medium-term program goals.