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Pirovich DB, Da'dara AA, Skelly PJ. GLYCOLYTIC ENZYMES AS VACCINES AGAINST SCHISTOSOMIASIS: TESTING SCHISTOSOMA MANSONI PHOSPHOGLYCERATE MUTASE IN MICE. J Parasitol 2024; 110:96-105. [PMID: 38466806 DOI: 10.1645/23-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2024] Open
Abstract
Schistosomiasis is a globally burdensome parasitic disease caused by flatworms (blood flukes) in the genus Schistosoma. The current standard treatment for schistosomiasis is the drug praziquantel, but there is an urgent need to advance novel interventions such as vaccines. Several glycolytic enzymes have been evaluated as vaccine targets for schistosomiasis, and data from these studies are reviewed here. Although these parasites are canonically considered to be intracellular, proteomic analysis has revealed that many schistosome glycolytic enzymes are additionally found at the host-interactive surface. We have recently found that the intravascular stage of Schistosoma mansoni (Sm) expresses the glycolytic enzyme phosphoglycerate mutase (PGM) on the tegumental surface. Live parasites display PGM activity, and suppression of PGM gene expression by RNA interference diminishes surface enzyme activity. Recombinant SmPGM (rSmPGM) can cleave its glycolytic substrate, 3-phosphoglycerate and can both bind to plasminogen and promote its conversion to an active form (plasmin) in vitro, suggesting a moonlighting role for this enzyme in regulating thrombosis in vivo. We found that antibodies in sera from chronically infected mice recognize rSmPGM. We also tested the protective efficacy of rSmPGM as a vaccine in the murine model. Although immunization generates high titers of anti-SmPGM antibodies (against both recombinant and native SmPGM), no significant differences in worm numbers were found between vaccinated and control animals.
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Affiliation(s)
- David B Pirovich
- Molecular Helminthology Laboratory, Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, North Grafton, Massachusetts 01536
| | - Akram A Da'dara
- Molecular Helminthology Laboratory, Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, North Grafton, Massachusetts 01536
| | - Patrick J Skelly
- Molecular Helminthology Laboratory, Department of Infectious Disease and Global Health, Cummings School of Veterinary Medicine, Tufts University, North Grafton, Massachusetts 01536
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2
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Coffeng LE, Stolk WA, de Vlas SJ. Predicting the risk and speed of drug resistance emerging in soil-transmitted helminths during preventive chemotherapy. Nat Commun 2024; 15:1099. [PMID: 38321011 PMCID: PMC10847116 DOI: 10.1038/s41467-024-45027-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 01/12/2024] [Indexed: 02/08/2024] Open
Abstract
Control of soil-transmitted helminths relies heavily on regular large-scale deworming of high-risk groups (e.g., children) with benzimidazole derivatives. Although drug resistance has not yet been documented in human soil-transmitted helminths, regular deworming of cattle and sheep has led to widespread benzimidazole resistance in veterinary helminths. Here we predict the population dynamics of human soil-transmitted helminth infections and drug resistance during 20 years of regular preventive chemotherapy, using an individual-based model. With the current preventive chemotherapy strategy of mainly targeting children in schools, drug resistance may evolve in soil-transmitted helminths within a decade. More intense preventive chemotherapy strategies increase the prospects of soil-transmitted helminths elimination, but also increase the speed at which drug efficacy declines, especially when implementing community-based preventive chemotherapy (population-wide deworming). If during the last decade, preventive chemotherapy against soil-transmitted helminths has led to resistance, we may not have detected it as drug efficacy has not been structurally monitored, or incorrectly so. These findings highlight the need to develop and implement strategies to monitor and mitigate the evolution of benzimidazole resistance.
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Affiliation(s)
- Luc E Coffeng
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
| | - Wilma A Stolk
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Sake J de Vlas
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
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3
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Summers S, Bhattacharyya T, Allan F, Stothard JR, Edielu A, Webster BL, Miles MA, Bustinduy AL. A review of the genetic determinants of praziquantel resistance in Schistosoma mansoni: Is praziquantel and intestinal schistosomiasis a perfect match? Front Trop Dis 2022. [DOI: 10.3389/fitd.2022.933097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Schistosomiasis is a neglected tropical disease (NTD) caused by parasitic trematodes belonging to the Schistosoma genus. The mainstay of schistosomiasis control is the delivery of a single dose of praziquantel (PZQ) through mass drug administration (MDA) programs. These programs have been successful in reducing the prevalence and intensity of infections. Due to the success of MDA programs, the disease has recently been targeted for elimination as a public health problem in some endemic settings. The new World Health Organization (WHO) treatment guidelines aim to provide equitable access to PZQ for individuals above two years old in targeted areas. The scale up of MDA programs may heighten the drug selection pressures on Schistosoma parasites, which could lead to the emergence of PZQ resistant schistosomes. The reliance on a single drug to treat a disease of this magnitude is worrying should drug resistance develop. Therefore, there is a need to detect and track resistant schistosomes to counteract the threat of drug resistance to the WHO 2030 NTD roadmap targets. Until recently, drug resistance studies have been hindered by the lack of molecular markers associated with PZQ resistance. This review discusses recent significant advances in understanding the molecular basis of PZQ action in S. mansoni and proposes additional genetic determinants associated with PZQ resistance. PZQ resistance will also be analyzed in the context of alternative factors that may decrease efficacy within endemic field settings, and the most recent treatment guidelines recommended by the WHO.
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Vianney TJ, Berger DJ, Doyle SR, Sankaranarayanan G, Serubanja J, Nakawungu PK, Besigye F, Sanya RE, Holroyd N, Allan F, Webb EL, Elliott AM, Berriman M, Cotton JA. Genome-wide analysis of Schistosoma mansoni reveals limited population structure and possible praziquantel drug selection pressure within Ugandan hot-spot communities. PLoS Negl Trop Dis 2022; 16:e0010188. [PMID: 35981002 PMCID: PMC9426917 DOI: 10.1371/journal.pntd.0010188] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 08/30/2022] [Accepted: 07/05/2022] [Indexed: 12/23/2022] Open
Abstract
Populations within schistosomiasis control areas, especially those in Africa, are recommended to receive regular mass drug administration (MDA) with praziquantel (PZQ) as the main strategy for controlling the disease. The impact of PZQ treatment on schistosome genetics remains poorly understood, and is limited by a lack of high-resolution genetic data on the population structure of parasites within these control areas. We generated whole-genome sequence data from 174 individual miracidia collected from both children and adults from fishing communities on islands in Lake Victoria in Uganda that had received either annual or quarterly MDA with PZQ over four years, including samples collected immediately before and four weeks after treatment. Genome variation within and between samples was characterised and we investigated genomic signatures of natural selection acting on these populations that could be due to PZQ treatment. The parasite population on these islands was more diverse than found in nearby villages on the lake shore. We saw little or no genetic differentiation between villages, or between the groups of villages with different treatment intensity, but slightly higher genetic diversity within the pre-treatment compared to post-treatment parasite populations. We identified classes of genes significantly enriched within regions of the genome with evidence of recent positive selection among post-treatment and intensively treated parasite populations. The differential selection observed in post-treatment and pre-treatment parasite populations could be linked to any reduced susceptibility of parasites to praziquantel treatment.
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Affiliation(s)
- Tushabe John Vianney
- Parasites and Microbes, Wellcome Sanger Institute, Hinxton, United Kingdom
- Immunomodulation and Vaccines Programme, Medical Research Council/Uganda Virus Research Institute and the London School of Hygiene & Tropical Medicine Uganda Research Unit, Entebbe, Uganda
| | - Duncan J. Berger
- Parasites and Microbes, Wellcome Sanger Institute, Hinxton, United Kingdom
| | - Stephen R. Doyle
- Parasites and Microbes, Wellcome Sanger Institute, Hinxton, United Kingdom
| | | | - Joel Serubanja
- Immunomodulation and Vaccines Programme, Medical Research Council/Uganda Virus Research Institute and the London School of Hygiene & Tropical Medicine Uganda Research Unit, Entebbe, Uganda
| | - Prossy Kabuubi Nakawungu
- Immunomodulation and Vaccines Programme, Medical Research Council/Uganda Virus Research Institute and the London School of Hygiene & Tropical Medicine Uganda Research Unit, Entebbe, Uganda
| | - Fred Besigye
- Immunomodulation and Vaccines Programme, Medical Research Council/Uganda Virus Research Institute and the London School of Hygiene & Tropical Medicine Uganda Research Unit, Entebbe, Uganda
| | - Richard E. Sanya
- Immunomodulation and Vaccines Programme, Medical Research Council/Uganda Virus Research Institute and the London School of Hygiene & Tropical Medicine Uganda Research Unit, Entebbe, Uganda
- Health and Systems for Health Unit, African Population and Health Research Center, Nairobi, Kenya
| | - Nancy Holroyd
- Parasites and Microbes, Wellcome Sanger Institute, Hinxton, United Kingdom
| | - Fiona Allan
- Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Emily L. Webb
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Alison M. Elliott
- Immunomodulation and Vaccines Programme, Medical Research Council/Uganda Virus Research Institute and the London School of Hygiene & Tropical Medicine Uganda Research Unit, Entebbe, Uganda
- Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Matthew Berriman
- Parasites and Microbes, Wellcome Sanger Institute, Hinxton, United Kingdom
| | - James A. Cotton
- Parasites and Microbes, Wellcome Sanger Institute, Hinxton, United Kingdom
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Clark J, Moses A, Nankasi A, Faust CL, Moses A, Ajambo D, Besigye F, Atuhaire A, Wamboko A, Carruthers LV, Francoeur R, Tukahebwa EM, Prada JM, Lamberton PHL. Reconciling Egg- and Antigen-Based Estimates of Schistosoma mansoni Clearance and Reinfection: A Modeling Study. Clin Infect Dis 2022; 74:1557-1563. [PMID: 34358299 PMCID: PMC9070857 DOI: 10.1093/cid/ciab679] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Despite decades of interventions, 240 million people have schistosomiasis. Infections cannot be directly observed, and egg-based Kato-Katz thick smears lack sensitivity, affected treatment efficacy and reinfection rate estimates. The point-of-care circulating cathodic antigen (referred to from here as POC-CCA+) test is advocated as an improvement on the Kato-Katz method, but improved estimates are limited by ambiguities in the interpretation of trace results. METHOD We collected repeated Kato-Katz egg counts from 210 school-aged children and scored POC-CCA tests according to the manufacturer's guidelines (referred to from here as POC-CCA+) and the externally developed G score. We used hidden Markov models parameterized with Kato-Katz; Kato-Katz and POC-CCA+; and Kato-Katz and G-Scores, inferring latent clearance and reinfection probabilities at four timepoints over six-months through a more formal statistical reconciliation of these diagnostics than previously conducted. Our approach required minimal but robust assumptions regarding trace interpretations. RESULTS Antigen-based models estimated higher infection prevalence across all timepoints compared with the Kato-Katz model, corresponding to lower clearance and higher reinfection estimates. Specifically, pre-treatment prevalence estimates were 85% (Kato-Katz; 95% CI: 79%-92%), 99% (POC-CCA+; 97%-100%) and 98% (G-Score; 95%-100%). Post-treatment, 93% (Kato-Katz; 88%-96%), 72% (POC-CCA+; 64%-79%) and 65% (G-Score; 57%-73%) of those infected were estimated to clear infection. Of those who cleared infection, 35% (Kato-Katz; 27%-42%), 51% (POC-CCA+; 41%-62%) and 44% (G-Score; 33%-55%) were estimated to have been reinfected by 9-weeks. CONCLUSIONS Treatment impact was shorter-lived than Kato-Katz-based estimates alone suggested, with lower clearance and rapid reinfection. At 3 weeks after treatment, longer-term clearance dynamics are captured. At 9 weeks after treatment, reinfection was captured, but failed clearance could not be distinguished from rapid reinfection. Therefore, frequent sampling is required to understand these important epidemiological dynamics.
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Affiliation(s)
- Jessica Clark
- Wellcome Centre for Integrative Parasitology, Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | | | | | - Christina L Faust
- Wellcome Centre for Integrative Parasitology, Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Adriko Moses
- Vector Control Division, Ministry of Health, Uganda
| | - Diana Ajambo
- Vector Control Division, Ministry of Health, Uganda
| | - Fred Besigye
- Vector Control Division, Ministry of Health, Uganda
| | | | | | - Lauren V Carruthers
- Wellcome Centre for Integrative Parasitology, Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Rachel Francoeur
- Wellcome Centre for Integrative Parasitology, Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
- Faculty of Science & Engineering, University of Chester, Chester, United Kingdom
| | | | - Joaquin M Prada
- Faculty of Health & Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Poppy H L Lamberton
- Wellcome Centre for Integrative Parasitology, Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
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6
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Platt RN, Le Clec'h W, Chevalier FD, McDew‐White M, LoVerde PT, Ramiro de Assis R, Oliveira G, Kinung'hi S, Djirmay AG, Steinauer ML, Gouvras A, Rabone M, Allan F, Webster BL, Webster JP, Emery AM, Rollinson D, Anderson TJC. Genomic analysis of a parasite invasion: Colonization of the Americas by the blood fluke Schistosoma mansoni. Mol Ecol 2022; 31:2242-2263. [PMID: 35152493 PMCID: PMC9305930 DOI: 10.1111/mec.16395] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 01/25/2022] [Accepted: 01/31/2022] [Indexed: 11/29/2022]
Abstract
Schistosoma mansoni, a snail-borne, blood fluke that infects humans, was introduced into the Americas from Africa during the Trans-Atlantic slave trade. As this parasite shows strong specificity to the snail intermediate host, we expected that adaptation to South American Biomphalaria spp. snails would result in population bottlenecks and strong signatures of selection. We scored 475,081 single nucleotide variants in 143 S. mansoni from the Americas (Brazil, Guadeloupe and Puerto Rico) and Africa (Cameroon, Niger, Senegal, Tanzania, and Uganda), and used these data to ask: (i) Was there a population bottleneck during colonization? (ii) Can we identify signatures of selection associated with colonization? (iii) What were the source populations for colonizing parasites? We found a 2.4- to 2.9-fold reduction in diversity and much slower decay in linkage disequilibrium (LD) in parasites from East to West Africa. However, we observed similar nuclear diversity and LD in West Africa and Brazil, suggesting no strong bottlenecks and limited barriers to colonization. We identified five genome regions showing selection in the Americas, compared with three in West Africa and none in East Africa, which we speculate may reflect adaptation during colonization. Finally, we infer that unsampled populations from central African regions between Benin and Angola, with contributions from Niger, are probably the major source(s) for Brazilian S. mansoni. The absence of a bottleneck suggests that this is a rare case of a serendipitous invasion, where S. mansoni parasites were pre-adapted to the Americas and able to establish with relative ease.
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Affiliation(s)
- Roy N. Platt
- Texas Biomedical Research InstituteSan AntonioTexasUSA
| | | | | | | | | | | | - Guilherme Oliveira
- Centro de Pesquisas René Rachou—Fiocruz/MGBelo HorizonteBrazil
- Instituto Tecnológico ValeBelémBrazil
| | | | - Amadou Garba Djirmay
- Réseau International Schistosomiases Environnemental Aménagement et Lutte (RISEAL)NiameyNiger
| | | | | | | | - Fiona Allan
- Department of Pathobiology and Population SciencesRoyal Veterinary College, Centre for Emerging, Endemic and Exotic DiseasesUniversity of LondonHertfordshireUK
- London Centre for Neglected Tropical Disease Research, Imperial College LondonSchool of Public HealthLondonUK
| | - Bonnie L. Webster
- Natural History MuseumLondonUK
- London Centre for Neglected Tropical Disease Research, Imperial College LondonSchool of Public HealthLondonUK
| | - Joanne P. Webster
- Department of Pathobiology and Population SciencesRoyal Veterinary College, Centre for Emerging, Endemic and Exotic DiseasesUniversity of LondonHertfordshireUK
- London Centre for Neglected Tropical Disease Research, Imperial College LondonSchool of Public HealthLondonUK
| | - Aidan M. Emery
- Natural History MuseumLondonUK
- London Centre for Neglected Tropical Disease Research, Imperial College LondonSchool of Public HealthLondonUK
| | - David Rollinson
- Natural History MuseumLondonUK
- London Centre for Neglected Tropical Disease Research, Imperial College LondonSchool of Public HealthLondonUK
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7
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Morad MY, El-Sayed H, Elhenawy AA, Korany SM, Aloufi AS, Ibrahim AM. Myco-Synthesized Molluscicidal and Larvicidal Selenium Nanoparticles: A New Strategy to Control Biomphalaria alexandrina Snails and Larvae of Schistosoma mansoni with an In Silico Study on Induced Oxidative Stress. J Fungi (Basel) 2022; 8:jof8030262. [PMID: 35330264 PMCID: PMC8952376 DOI: 10.3390/jof8030262] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 02/26/2022] [Accepted: 02/27/2022] [Indexed: 12/13/2022] Open
Abstract
Schistosomiasis is a tropical disease with socioeconomic problems. The goal of this study was to determine the influence of myco-synthesized nano-selenium (SeNPs) as a molluscicide on Biomphlaria alexandrina snails, with the goal of reducing disease spread via non-toxic routes. In this study, Penicillium chrysogenum culture filtrate metabolites were used as a reductant for selenium ions to form nano-selenium. The SeNPs were characterized via UV-Vis spectrophotometer, Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS), and X-ray diffraction (XRD). Myco-synthesized SeNPs had a significant molluscicidal effect on B. alexandrina snails after 96 h of exposure at a concentration of 5.96 mg/L. SeNPs also had miracidicidal and cercaricidal properties against S. mansoni. Some alterations were observed in the hemocytes of snails exposed to SeNPs, including the formation of pseudopodia and an increasing number of granules. Furthermore, lipid peroxide, nitric oxide (NO), malondialdehyde (MDA), and glutathione s-transferase (GST) increased significantly in a dose-dependent manner, while superoxide dismutase (SOD) decreased. The comet assay revealed that myco-synthesized SeNPs could cause breaks in the DNA levels. In silico study revealed that SeNPs had promising antioxidant properties. In conclusion, myco-synthesized SeNPs have the potential to be used as molluscicides and larvicides.
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Affiliation(s)
- Mostafa Y. Morad
- Zoology and Entomology Department, Faculty of Science, Helwan University, Helwan 11795, Egypt;
| | - Heba El-Sayed
- Botany and Microbiology Department, Faculty of Science, Helwan University, Helwan 11795, Egypt;
| | - Ahmed A. Elhenawy
- Chemistry Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo 11884, Egypt;
- Chemistry Department, Faculty of Science and Art, Al Baha University, Mukhwah, Al Baha 6531, Saudi Arabia
| | - Shereen M. Korany
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia;
| | - Abeer S. Aloufi
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia;
- Correspondence:
| | - Amina M. Ibrahim
- Medical Malacology Department, Theodor Bilharz Research Institute, Giza 12411, Egypt;
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8
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Lund AJ, Wade KJ, Nikolakis ZL, Ivey KN, Perry BW, Pike HNC, Paull SH, Liu Y, Castoe TA, Pollock DD, Carlton EJ. Integrating genomic and epidemiologic data to accelerate progress toward schistosomiasis elimination. eLife 2022; 11:79320. [PMID: 36040013 PMCID: PMC9427098 DOI: 10.7554/elife.79320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 08/11/2022] [Indexed: 11/13/2022] Open
Abstract
The global community has adopted ambitious goals to eliminate schistosomiasis as a public health problem, and new tools are needed to achieve them. Mass drug administration programs, for example, have reduced the burden of schistosomiasis, but the identification of hotspots of persistent and reemergent transmission threaten progress toward elimination and underscore the need to couple treatment with interventions that reduce transmission. Recent advances in DNA sequencing technologies make whole-genome sequencing a valuable and increasingly feasible option for population-based studies of complex parasites such as schistosomes. Here, we focus on leveraging genomic data to tailor interventions to distinct social and ecological circumstances. We consider two priority questions that can be addressed by integrating epidemiological, ecological, and genomic information: (1) how often do non-human host species contribute to human schistosome infection? and (2) what is the importance of locally acquired versus imported infections in driving transmission at different stages of elimination? These questions address processes that can undermine control programs, especially those that rely heavily on treatment with praziquantel. Until recently, these questions were difficult to answer with sufficient precision to inform public health decision-making. We review the literature related to these questions and discuss how whole-genome approaches can identify the geographic and taxonomic sources of infection, and how such information can inform context-specific efforts that advance schistosomiasis control efforts and minimize the risk of reemergence.
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Affiliation(s)
- Andrea J Lund
- Department of Environmental and Occupational Health, Colorado School of Public Health, University of Colorado AnschutzAuroraUnited States
| | - Kristen J Wade
- Department of Biochemistry & Molecular Genetics, University of Colorado School of MedicineAuroraUnited States
| | - Zachary L Nikolakis
- Department of Biology, University of Texas at ArlingtonArlingtonUnited States
| | - Kathleen N Ivey
- Department of Biology, University of Texas at ArlingtonArlingtonUnited States
| | - Blair W Perry
- Department of Biology, University of Texas at ArlingtonArlingtonUnited States
| | - Hamish NC Pike
- Department of Biochemistry & Molecular Genetics, University of Colorado School of MedicineAuroraUnited States
| | - Sara H Paull
- Department of Environmental and Occupational Health, Colorado School of Public Health, University of Colorado AnschutzAuroraUnited States
| | - Yang Liu
- Sichuan Centers for Disease Control and PreventionChengduChina
| | - Todd A Castoe
- Department of Biology, University of Texas at ArlingtonArlingtonUnited States
| | - David D Pollock
- Department of Biochemistry & Molecular Genetics, University of Colorado School of MedicineAuroraUnited States
| | - Elizabeth J Carlton
- Department of Environmental and Occupational Health, Colorado School of Public Health, University of Colorado AnschutzAuroraUnited States
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9
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Berger DJ, Crellen T, Lamberton PHL, Allan F, Tracey A, Noonan JD, Kabatereine NB, Tukahebwa EM, Adriko M, Holroyd N, Webster JP, Berriman M, Cotton JA. Whole-genome sequencing of Schistosoma mansoni reveals extensive diversity with limited selection despite mass drug administration. Nat Commun 2021; 12:4776. [PMID: 34362894 PMCID: PMC8346512 DOI: 10.1038/s41467-021-24958-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 07/06/2021] [Indexed: 02/07/2023] Open
Abstract
Control and elimination of the parasitic disease schistosomiasis relies on mass administration of praziquantel. Whilst these programmes reduce infection prevalence and intensity, their impact on parasite transmission and evolution is poorly understood. Here we examine the genomic impact of repeated mass drug administration on Schistosoma mansoni populations with documented reduced praziquantel efficacy. We sequenced whole-genomes of 198 S. mansoni larvae from 34 Ugandan children from regions with contrasting praziquantel exposure. Parasites infecting children from Lake Victoria, a transmission hotspot, form a diverse panmictic population. A single round of treatment did not reduce this diversity with no apparent population contraction caused by long-term praziquantel use. We find evidence of positive selection acting on members of gene families previously implicated in praziquantel action, but detect no high frequency functionally impactful variants. As efforts to eliminate schistosomiasis intensify, our study provides a foundation for genomic surveillance of this major human parasite.
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Affiliation(s)
- Duncan J Berger
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, UK.
- Department of Pathology and Pathogen Biology, Centre for Emerging, Endemic and Exotic Diseases, Royal Veterinary College, University of London, Herts, UK.
| | - Thomas Crellen
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, UK
- Imperial College London, Department of Infectious Disease Epidemiology, London, UK
- Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Poppy H L Lamberton
- Imperial College London, Department of Infectious Disease Epidemiology, London, UK
- Institute for Biodiversity, Animal Health, and Comparative Medicine, and Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, UK
| | - Fiona Allan
- The Natural History Museum, Department of Life Sciences, London, UK
| | - Alan Tracey
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, UK
| | - Jennifer D Noonan
- Institute of Parasitology, Faculty of Agricultural and Environmental Sciences, McGill University, Montreal, Quebec, Canada
| | - Narcis B Kabatereine
- Vector Borne & Neglected Tropical Disease Control Division, Ministry of Health, Kampala, Uganda
| | - Edridah M Tukahebwa
- Vector Borne & Neglected Tropical Disease Control Division, Ministry of Health, Kampala, Uganda
| | - Moses Adriko
- Vector Borne & Neglected Tropical Disease Control Division, Ministry of Health, Kampala, Uganda
| | - Nancy Holroyd
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, UK
| | - Joanne P Webster
- Department of Pathology and Pathogen Biology, Centre for Emerging, Endemic and Exotic Diseases, Royal Veterinary College, University of London, Herts, UK.
- Imperial College London, Department of Infectious Disease Epidemiology, London, UK.
| | - Matthew Berriman
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, UK.
| | - James A Cotton
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridgeshire, UK.
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10
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do Carmo Neto JR, Guerra RO, Machado JR, Silva ACA, da Silva MV. Antiprotozoal and anthelmintic activity of zinc oxide nanoparticles. Curr Med Chem 2021; 29:2127-2141. [PMID: 34254904 DOI: 10.2174/0929867328666210709105850] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 05/10/2021] [Accepted: 05/13/2021] [Indexed: 11/22/2022]
Abstract
Nanomaterials represent a wide alternative for the treatment of several diseases that affect both human and animal health. The use of these materials mainly involves trying to solve the problem of resistance that pathogenic organisms acquire to conventional drugs. A well-studied example that represents a potential component for biomedical applications is the use of zinc oxide (ZnO) nanoparticles (NPs). Its antimicrobial function is related, especially the ability to generate/induce ROS that affects the homeostasis of the pathogen in question. Protozoa and helminths that harm human health and the economic performance of animals have already been exposed to this type of nanoparticle. Thus, through this review, our goal is to discuss the state-of-the-art effect of ZnO NPs on these parasites.
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Affiliation(s)
- José Rodrigues do Carmo Neto
- Department of Bioscience and Technology, Institute of Tropical Pathology and Public Health, Federal University of Goias, 74605-450 Goiania, GO, Brazil
| | - Rhanoica Oliveira Guerra
- Department of Microbiology, Immunology and Parasitology, Institute of Biological and Natural Sciences of Federal University of Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Juliana Reis Machado
- Department of General Pathology, Federal University of Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Anielle Christine Almeida Silva
- Laboratório de Novos Materiais Nanoestruturados e Funcionais (LNMIS), Physics Institute, Federal University of Alagoas, Maceió, Alagoas, Brazil
| | - Marcos Vinicius da Silva
- Department of Microbiology, Immunology and Parasitology, Institute of Biological and Natural Sciences of Federal University of Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
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11
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Shortt JA, Timm LE, Hales NR, Nikolakis ZL, Schield DR, Perry BW, Liu Y, Zhong B, Castoe TA, Carlton EJ, Pollock DD. Population genomic analyses of schistosome parasites highlight critical challenges facing endgame elimination efforts. Sci Rep 2021; 11:6884. [PMID: 33767307 DOI: 10.1038/s41598-021-86287-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 03/09/2021] [Indexed: 12/14/2022] Open
Abstract
Schistosomiasis persists in Asian regions despite aggressive elimination measures. To identify factors enabling continued parasite transmission, we performed reduced representation genome sequencing on Schistosoma japonicum miracidia collected across multiple years from transmission hotspots in Sichuan, China. We discovered strong geographic structure, suggesting that local, rather than imported, reservoirs are key sources of persistent infections in the region. At the village level, parasites collected after referral for praziquantel treatment are closely related to local pre-treatment populations. Schistosomes within villages are also highly related, suggesting that only a few parasites from a limited number of hosts drive re-infection. The close familial relationships among miracidia from different human hosts also implicate short transmission routes among humans. At the individual host level, genetic evidence indicates that multiple humans retained infections following referral for treatment. Our findings suggest that end-game schistosomiasis control measures should focus on completely extirpating local parasite reservoirs and confirming successful treatment of infected human hosts.
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12
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Mawa PA, Kincaid-Smith J, Tukahebwa EM, Webster JP, Wilson S. Schistosomiasis Morbidity Hotspots: Roles of the Human Host, the Parasite and Their Interface in the Development of Severe Morbidity. Front Immunol 2021; 12:635869. [PMID: 33790908 PMCID: PMC8005546 DOI: 10.3389/fimmu.2021.635869] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 02/25/2021] [Indexed: 12/14/2022] Open
Abstract
Schistosomiasis is the second most important human parasitic disease in terms of socioeconomic impact, causing great morbidity and mortality, predominantly across the African continent. For intestinal schistosomiasis, severe morbidity manifests as periportal fibrosis (PPF) in which large tracts of macro-fibrosis of the liver, visible by ultrasound, can occlude the main portal vein leading to portal hypertension (PHT), sequelae such as ascites and collateral vasculature, and ultimately fatalities. For urogenital schistosomiasis, severe morbidity manifests as pathology throughout the urinary system and genitals, and is a definitive cause of squamous cell bladder carcinoma. Preventative chemotherapy (PC) programmes, delivered through mass drug administration (MDA) of praziquantel (PZQ), have been at the forefront of schistosomiasis control programmes in sub-Saharan Africa since their commencement in Uganda in 2003. However, despite many successes, 'biological hotspots' (as distinct from 'operational hotspots') of both persistent high transmission and morbidity remain. In some areas, this failure to gain control of schistosomiasis has devastating consequences, with not only persistently high infection intensities, but both "subtle" and severe morbidity remaining prevalent. These hotspots highlight the requirement to revisit research into severe morbidity and its mechanisms, a topic that has been out of favor during times of PC implementation. Indeed, the focality and spatially-structured epidemiology of schistosomiasis, its transmission persistence and the morbidity induced, has long suggested that gene-environmental-interactions playing out at the host-parasite interface are crucial. Here we review evidence of potential unique parasite factors, host factors, and their gene-environmental interactions in terms of explaining differential morbidity profiles in the human host. We then take the situation of schistosomiasis mansoni within the Albertine region of Uganda as a case study in terms of elucidating the factors behind the severe morbidity observed and the avenues and directions for future research currently underway within a new research and clinical trial programme (FibroScHot).
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Affiliation(s)
- Patrice A. Mawa
- Immunomodulation and Vaccines Programme, Medical Research Council-Uganda Virus Research Institute and London School of Hygiene and Tropical Medicine (MRC/UVRI and LSHTM) Uganda Research Unit, Entebbe, Uganda
- Department of Immunology, Uganda Virus Research Institute, Entebbe, Uganda
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Julien Kincaid-Smith
- Centre for Emerging, Endemic and Exotic Diseases (CEEED), Department of Pathobiology and Population Sciences (PPS), Royal Veterinary College, University of London, Herts, United Kingdom
| | | | - Joanne P. Webster
- Centre for Emerging, Endemic and Exotic Diseases (CEEED), Department of Pathobiology and Population Sciences (PPS), Royal Veterinary College, University of London, Herts, United Kingdom
| | - Shona Wilson
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
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13
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Rey O, Webster BL, Huyse T, Rollinson D, Van den Broeck F, Kincaid-Smith J, Onyekwere A, Boissier J. Population genetics of African Schistosoma species. Infect Genet Evol 2021; 89:104727. [PMID: 33486128 DOI: 10.1016/j.meegid.2021.104727] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 01/09/2021] [Accepted: 01/13/2021] [Indexed: 02/06/2023]
Abstract
Blood flukes within the genus Schistosoma (schistosomes) are responsible for the major disease, schistosomiasis, in tropical and sub-tropical areas. This disease is predominantly present on the African continent with more than 85% of the human cases. Schistosomes are also parasites of veterinary importance infecting livestock and wildlife. Schistosoma population genetic structure and diversity are important characteristics that may reflect variations in selection pressures such as those induced by host (mammalian and snail) environments, habitat change, migration and also treatment/control interventions, all of which also shape speciation and evolution of the whole Schistosoma genus. Investigations into schistosome population genetic structure, diversity and evolution has been an area of important debate and research. Supported by advances in molecular techniques with capabilities for multi-locus genetic analyses for single larvae schistosome genetic investigations have greatly progressed in the last decade. This paper aims to review the genetic studies of both animal and human infecting schistosome. Population genetic structures are reviewed at different spatial scales: local, regional or continental (i.e. phylogeography). Within species genetic diversities are discussed compared and the compounding factors discussed, including the effect of mass drug administration. Finally, the ability for intra-species hybridisation questions species integrities and poses many questions in relation to the natural epidemiology of co-endemic species. Here we review molecularly confirmed hybridisation events (in relation to human disease) and discuss the possible impact for ongoing and future control and elimination.
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Affiliation(s)
- O Rey
- Univ. Montpellier, CNRS, IFREMER, UPVD, IHPE, F-66000 Perpignan, France
| | - B L Webster
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London SW7 5BD, United Kingdom; London Centre for Neglected Tropical Disease Research, Imperial College London School of Public Health, London W2 1PG, United Kingdom
| | - T Huyse
- Department of Biology, Royal Museum for Central Africa, Leuvensesteenweg 13, B-3080 Tervuren, Belgium; Laboratory of Biodiversity and Evolutionary Genomics, Department of Biology, KU Leuven, Ch. Deberiotstraat 32, B-3000 Leuven, Belgium
| | - D Rollinson
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London SW7 5BD, United Kingdom; London Centre for Neglected Tropical Disease Research, Imperial College London School of Public Health, London W2 1PG, United Kingdom
| | - F Van den Broeck
- Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, University of Leuven, Leuven, Belgium; Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - J Kincaid-Smith
- Centre for Emerging, Endemic and Exotic Diseases (CEEED), Department of Pathobiology and Population Sciences (PPS), Royal Veterinary College, University of London, Hawkshead Campus, Herts AL9 7TA, United Kingdom
| | - A Onyekwere
- Univ. Montpellier, CNRS, IFREMER, UPVD, IHPE, F-66000 Perpignan, France
| | - J Boissier
- Univ. Montpellier, CNRS, IFREMER, UPVD, IHPE, F-66000 Perpignan, France.
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14
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Kotze AC, Gilleard JS, Doyle SR, Prichard RK. Challenges and opportunities for the adoption of molecular diagnostics for anthelmintic resistance. Int J Parasitol Drugs Drug Resist 2020; 14:264-273. [PMID: 33307336 PMCID: PMC7726450 DOI: 10.1016/j.ijpddr.2020.11.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 11/22/2020] [Accepted: 11/26/2020] [Indexed: 02/06/2023]
Abstract
Anthelmintic resistance is a significant threat to livestock production systems worldwide and is emerging as an important issue in companion animal parasite management. It is also an emerging concern for the control of human soil-transmitted helminths and filaria. An important aspect of managing anthelmintic resistance is the ability to utilise diagnostic tests to detect its emergence at an early stage. In host-parasite systems where resistance is already widespread, diagnostics have a potentially important role in determining those drugs that remain the most effective. The development of molecular diagnostics for anthelmintic resistance is one focus of the Consortium for Anthelmintic Resistance and Susceptibility (CARS) group. The present paper reflects discussions of this issue that occurred at the most recent meeting of the group in Wisconsin, USA, in July 2019. We compare molecular resistance diagnostics with in vivo and in vitro phenotypic methods, and highlight the advantages and disadvantages of each. We assess whether our knowledge on the identity of molecular markers for resistance towards the different drug classes is sufficient to provide some expectation that molecular tests for field use may be available in the short-to-medium term. We describe some practical aspects of such tests and how our current capabilities compare to the requirements of an 'ideal' test. Finally, we describe examples of drug class/parasite species interactions that provide the best opportunity for commercial use of molecular tests in the near future. We argue that while such prototype tests may not satisfy the requirements of an 'ideal' test, their potential to provide significant advances over currently-used phenotypic methods warrants their development as field diagnostics.
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Affiliation(s)
- Andrew C. Kotze
- CSIRO Agriculture and Food, St. Lucia, Brisbane, 4072, QLD, Australia,Corresponding author. , CSIRO Agriculture and Food, St. Lucia, Brisbane, 4072, QLD, Australia.
| | - John S. Gilleard
- Department of Comparative Biology and Experimental Medicine, Host-Parasite Interactions Program, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
| | - Stephen R. Doyle
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Roger K. Prichard
- Institute of Parasitology, McGill University, Sainte Anne-de-Bellevue, QC, H9X 3V9, Canada
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15
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Kura K, Hardwick RJ, Truscott JE, Toor J, Hollingsworth TD, Anderson RM. The impact of mass drug administration on Schistosoma haematobium infection: what is required to achieve morbidity control and elimination? Parasit Vectors 2020; 13:554. [PMID: 33203467 PMCID: PMC7672840 DOI: 10.1186/s13071-020-04409-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 10/21/2020] [Indexed: 12/01/2022] Open
Abstract
Background Schistosomiasis remains an endemic parasitic disease causing much morbidity and, in some cases, mortality. The World Health Organization (WHO) has outlined strategies and goals to combat the burden of disease caused by schistosomiasis. The first goal is morbidity control, which is defined by achieving less than 5% prevalence of heavy intensity infection in school-aged children (SAC). The second goal is elimination as a public health problem (EPHP), achieved when the prevalence of heavy intensity infection in SAC is reduced to less than 1%. Mass drug administration (MDA) of praziquantel is the main strategy for control. However, there is limited availability of praziquantel, particularly in Africa where there is high prevalence of infection. It is therefore important to explore whether the WHO goals can be achieved using the current guidelines for treatment based on targeting SAC and, in some cases, adults. Previous modelling work has largely focused on Schistosoma mansoni, which in advance cases can cause liver and spleen enlargement. There has been much less modelling of the transmission of Schistosoma haematobium, which in severe cases can cause kidney damage and bladder cancer. This lack of modelling has largely been driven by limited data availability and challenges in interpreting these data. Results In this paper, using an individual-based stochastic model and age-intensity profiles of S. haematobium from two different communities, we calculate the probability of achieving the morbidity and EPHP goals within 15 years of treatment under the current WHO treatment guidelines. We find that targeting SAC only can achieve the morbidity goal for all transmission settings, regardless of the burden of infection in adults. The EPHP goal can be achieved in low transmission settings, but in some moderate to high settings community-wide treatment is needed. Conclusions We show that the key determinants of achieving the WHO goals are the precise form of the age-intensity of infection profile and the baseline SAC prevalence. Additionally, we find that the higher the burden of infection in adults, the higher the chances that adults need to be included in the treatment programme to achieve EPHP.
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Affiliation(s)
- Klodeta Kura
- London Centre for Neglected Tropical Disease Research, London, UK. .,Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary's Campus, Imperial College London, London, UK. .,MRC Centre for Global Infectious Disease Analysis, London, UK.
| | - Robert J Hardwick
- London Centre for Neglected Tropical Disease Research, London, UK.,Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary's Campus, Imperial College London, London, UK.,MRC Centre for Global Infectious Disease Analysis, London, UK.,The DeWorm3 Project, The Natural History Museum of London, London, UK
| | - James E Truscott
- London Centre for Neglected Tropical Disease Research, London, UK.,Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary's Campus, Imperial College London, London, UK.,MRC Centre for Global Infectious Disease Analysis, London, UK.,The DeWorm3 Project, The Natural History Museum of London, London, UK
| | - Jaspreet Toor
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7LF, UK
| | - T Deirdre Hollingsworth
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, OX3 7LF, UK
| | - Roy M Anderson
- London Centre for Neglected Tropical Disease Research, London, UK.,Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary's Campus, Imperial College London, London, UK.,MRC Centre for Global Infectious Disease Analysis, London, UK.,The DeWorm3 Project, The Natural History Museum of London, London, UK
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16
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Webster JP, Neves MI, Webster BL, Pennance T, Rabone M, Gouvras AN, Allan F, Walker M, Rollinson D. Parasite Population Genetic Contributions to the Schistosomiasis Consortium for Operational Research and Evaluation within Sub-Saharan Africa. Am J Trop Med Hyg 2020; 103:80-91. [PMID: 32400355 PMCID: PMC7351308 DOI: 10.4269/ajtmh.19-0827] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Analyses of the population genetic structure of schistosomes under the "Schistosomiasis Consortium for Operational Research and Evaluation" (SCORE) contrasting treatment pressure scenarios in Tanzania, Niger, and Zanzibar were performed to provide supplementary critical information with which to evaluate the impact of these large-scale control activities and guide how activities could be adjusted. We predicted that population genetic analyses would reveal information on a range of important parameters including, but not exclusive to, recruitment and transmission of genotypes, occurrence of hybridization events, differences in reproductive mode, and degrees of inbreeding, and hence, the evolutionary potential, and responses of parasite populations under contrasting treatment pressures. Key findings revealed that naturally high levels of gene flow and mixing of the parasite populations between neighboring sites were likely to dilute any effects imposed by the SCORE treatment arms. Furthermore, significant inherent differences in parasite fecundity were observed, independent of current treatment arm, but potentially of major impact in terms of maintaining high levels of ongoing transmission in persistent "biological hotspot" sites. Within Niger, naturally occurring Schistosoma haematobium/Schistosoma bovis viable hybrids were found to be abundant, often occurring in significantly higher proportions than that of single-species S. haematobium infections. By examining parasite population genetic structures across hosts, treatment regimens, and the spatial landscape, our results to date illustrate key transmission processes over and above that which could be achieved through standard parasitological monitoring of prevalence and intensity alone, as well as adding to our understanding of Schistosoma spp. life history strategies in general.
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Affiliation(s)
- Joanne P Webster
- London Centre for Neglected Tropical Disease Research (LCNTDR), Imperial College Faculty of Medicine, London, United Kingdom.,Department of Pathobiology and Population Sciences, Centre for Emerging, Endemic and Exotic Diseases (CEEED), Royal Veterinary College, University of London, Hawkshead Campus, Herts, United Kingdom
| | - Maria Inês Neves
- London Centre for Neglected Tropical Disease Research (LCNTDR), Imperial College Faculty of Medicine, London, United Kingdom.,Department of Pathobiology and Population Sciences, Centre for Emerging, Endemic and Exotic Diseases (CEEED), Royal Veterinary College, University of London, Hawkshead Campus, Herts, United Kingdom
| | - Bonnie L Webster
- Department of Life Sciences, Wolfson Wellcome Biomedical Laboratories, The Natural History Museum, London, United Kingdom.,London Centre for Neglected Tropical Disease Research (LCNTDR), Imperial College Faculty of Medicine, London, United Kingdom
| | - Tom Pennance
- School of Biosciences, Cardiff University, Cardiff, United Kingdom.,Department of Life Sciences, Wolfson Wellcome Biomedical Laboratories, The Natural History Museum, London, United Kingdom.,London Centre for Neglected Tropical Disease Research (LCNTDR), Imperial College Faculty of Medicine, London, United Kingdom
| | - Muriel Rabone
- Department of Life Sciences, Wolfson Wellcome Biomedical Laboratories, The Natural History Museum, London, United Kingdom.,London Centre for Neglected Tropical Disease Research (LCNTDR), Imperial College Faculty of Medicine, London, United Kingdom
| | - Anouk N Gouvras
- Department of Life Sciences, Wolfson Wellcome Biomedical Laboratories, The Natural History Museum, London, United Kingdom.,London Centre for Neglected Tropical Disease Research (LCNTDR), Imperial College Faculty of Medicine, London, United Kingdom
| | - Fiona Allan
- Department of Life Sciences, Wolfson Wellcome Biomedical Laboratories, The Natural History Museum, London, United Kingdom.,London Centre for Neglected Tropical Disease Research (LCNTDR), Imperial College Faculty of Medicine, London, United Kingdom
| | - Martin Walker
- London Centre for Neglected Tropical Disease Research (LCNTDR), Imperial College Faculty of Medicine, London, United Kingdom.,Department of Pathobiology and Population Sciences, Centre for Emerging, Endemic and Exotic Diseases (CEEED), Royal Veterinary College, University of London, Hawkshead Campus, Herts, United Kingdom
| | - David Rollinson
- Department of Life Sciences, Wolfson Wellcome Biomedical Laboratories, The Natural History Museum, London, United Kingdom.,London Centre for Neglected Tropical Disease Research (LCNTDR), Imperial College Faculty of Medicine, London, United Kingdom
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17
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Trienekens SCM, Faust CL, Meginnis K, Pickering L, Ericsson O, Nankasi A, Moses A, Tukahebwa EM, Lamberton PHL. Impacts of host gender on Schistosoma mansoni risk in rural Uganda-A mixed-methods approach. PLoS Negl Trop Dis 2020; 14:e0008266. [PMID: 32401770 DOI: 10.1371/journal.pntd.0008266] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 04/02/2020] [Indexed: 12/12/2022] Open
Abstract
Background The World Health Organization identified Uganda as one of the 10 highly endemic countries for schistosomiasis. Annual mass drug administration (MDA) with praziquantel has led to a decline in intensity of Schistosoma mansoni infections in several areas. However, as hotspots with high (re)infection rates remain, additional research on risk factors and implementing interventions to complement MDA are required to further reduce disease burden in these settings. Through a mixed-methods study we aimed to gain deeper understanding of how gender may impact risk and reinfection in order to inform disease control programmes and ascertain if gender-specific interventions may be beneficial. Methodology/Principal findings In Bugoto, Mayuge District, Eastern Uganda we conducted ethnographic observations (n = 16) and examined epidemiology (n = 55) and parasite population genetics (n = 16) in school-aged children (SAC), alongside a community-wide household survey (n = 130). Water contact was frequent at home, school and in the community and was of domestic, personal care, recreational, religious or commercial nature. Qualitative analysis of type of activity, duration, frequency, level of submersion and water contact sites in children showed only few behavioural differences in water contact between genders. However, survey data revealed that adult women carried out the vast majority of household tasks involving water contact. Reinfection rates (96% overall) and genetic diversity were high in boys (pre-He = 0.66; post-He = 0.67) and girls (pre-He = 0.65; post-He = 0.67), but no differences in reinfection rates (p = 0.62) or genetic diversity by gender before (p = 0.54) or after (p = 0.97) treatment were found. Conclusions/Significance This mixed methods approach showed complementary findings. Frequent water exposure with few differences between boys and girls was mirrored by high reinfection rates and genetic diversity in both genders. Disease control programmes should consider the high reinfection rates among SAC in remaining hotspots of schistosomiasis and the various purposes and settings in which children and adults are exposed to water. Globally, over 230 million people are infected with schistosomiasis, an infectious disease caused by parasitic helminths. Humans can get infected when they contact water which contains Schistosoma parasites. Although the disease can be treated with a drug, people get rapidly reinfected in certain high-transmission settings. Drug treatment alone may not be sufficient to eliminate this disease and additional interventions such as health promotion or improvements in water and sanitation need to be scaled up. To provide recommendations to these control programmes we carried out interdisciplinary research in Eastern Uganda to understand the influence of gender on schistosomiasis risk. We found that the water contact behaviour of boys and girls is quite similar, and we did not see differences in reinfection or genetic diversity of the parasite between boys and girls. Differences in water contact between genders is greater in adults, and further research is required for these individuals. In this setting, infection rates are high in school-aged children and there are no differences between genders. These results emphasise improved control efforts for all school-aged children in communities like these. Our interdisciplinary approach provided complementary findings. Such an integrated approach can therefore have more power to meaningfully inform policy on schistosomiasis control.
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