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Belizario VY, de Cadiz AE, Sison OT, Medina JRC, Ong LAD, Alonte AJI. Low schistosomiasis and soil-transmitted helminthiasis prevalence and intensities in selected communities in Davao de Oro and Davao del Norte, the Philippines: A setting for interruption of transmission? Parasitol Int 2024; 102:102901. [PMID: 38754812 DOI: 10.1016/j.parint.2024.102901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 05/13/2024] [Accepted: 05/13/2024] [Indexed: 05/18/2024]
Abstract
Parasitic neglected tropical diseases, such as schistosomiasis and soil-transmitted helminthiasis (STH), remain as significant public health concerns in developing countries such as the Philippines. This study aimed to determine the prevalence and intensity of schistosomiasis and STH among school-age children (SAC) and adults in two co-endemic provinces in Mindanao in southern Philippines as part of monitoring of national control programs. Stool samples were collected, processed using Kato-Katz technique, and examined microscopically for presence of intestinal helminth ova. A total of 776 SAC and 526 adults participated in the study. Low schistosomiasis prevalence was generally observed in SAC (0.8%) and adults (0.4%). Generally low STH prevalence was reported in both SAC (3.9%) and adults (3.4%). Only three SAC had heavy intensity STH, which was not seen in adults. Results indicate a state of good morbidity control, which may be a result of effective implementation of mass drug administration (MDA) strategy for schistosomiasis, STH, and lymphatic filariasis in the last several years. The low prevalence and intensities of infections may also be partly attributed to the low diagnostic sensitivity of Kato-Katz technique in detecting low intensity intestinal helminth infections. While results of this study also indicate similarly low levels of both these infections in previous studies, sustaining high MDA coverage rates and addressing remaining challenges related to intensified case finding and treatment, improvements in safe water, sanitation, and hygiene, veterinary public health, and vector ecology and management will be necessary to interrupt transmission in these areas.
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Affiliation(s)
- Vicente Y Belizario
- College of Public Health, University of the Philippines Manila, 625 Pedro Gil St., Ermita, Manila, 1000, Metro Manila, Philippines; Neglected Tropical Diseases Study Group, National Institutes of Health, University of the Philippines Manila, 623 Pedro Gil St., Ermita, Manila, 1000, Metro Manila, Philippines.
| | - Aleyla E de Cadiz
- College of Science and Mathematics, University of the Philippines Mindanao, Tugbok, Davao City, 8000, Davao del Sur, Philippines
| | - Olivia T Sison
- Institute of Clinical Epidemiology, National Institutes of Health, University of the Philippines Manila, 623 Pedro Gil St., Ermita, Manila, 1000, Metro Manila, Philippines
| | - John Robert C Medina
- Institute of Clinical Epidemiology, National Institutes of Health, University of the Philippines Manila, 623 Pedro Gil St., Ermita, Manila, 1000, Metro Manila, Philippines
| | - Lynnell Alexie D Ong
- Neglected Tropical Diseases Study Group, National Institutes of Health, University of the Philippines Manila, 623 Pedro Gil St., Ermita, Manila, 1000, Metro Manila, Philippines
| | - Allen Jethro I Alonte
- Neglected Tropical Diseases Study Group, National Institutes of Health, University of the Philippines Manila, 623 Pedro Gil St., Ermita, Manila, 1000, Metro Manila, Philippines
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Chanhanga N, Mindu T, Mogaka J, Chimbari M. The Impact of Targeted Treatment and Mass Drug Administration Delivery Strategies on the Prevalence and Intensity of Schistosomiasis in School Aged Children in Africa: A Systematic Review. Infect Drug Resist 2023; 16:2453-2466. [PMID: 37138838 PMCID: PMC10150034 DOI: 10.2147/idr.s395382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 03/16/2023] [Indexed: 05/05/2023] Open
Abstract
Schistosomiasis is a public health problem in more than 78 countries in the world. The disease is most prevalent among children than adults due to their high exposure to infectious water sources. Various interventions such as mass drug administration (MDA), snail control, safe water provision and health education have been implemented independently or jointly to control, reduce and ultimately eliminate Schistosomiasis. This scoping review focused on studies reporting the impact of different delivery strategies of targeted treatment and MDA on the prevalence and intensity of schistosomiasis infection in school aged children in Africa. The review focused on Schistosoma haematobium and Schistosoma mansoni species. A systematic search for eligible literature from peer-reviewed articles was done from Google Scholar, Medline, PubMed and EBSCO host databases. The search yielded twenty-seven peer-reviewed articles. All articles found reported a decrease in the prevalence of schistosomiasis infection. Five studies (18.5%) reported a prevalence change below 40%, eighteen studies (66.7%) reported a change between 40% and 80%, and four studies (14.8%) reported a change above 80%. The infection intensity post-treatment was varied: twenty-four studies reported a decrease, while two studies reported an increase. The review showed that the impact of targeted treatment on the prevalence and intensity of schistosomiasis depended on the frequency at which it was offered, complementary interventions, and its uptake by the target population. Targeted treatment can significantly control the infection burden, but cannot eliminate the disease. Constant MDA programs coupled with preventative and health promotional programs are required to reach the elimination stage.
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Affiliation(s)
- Nathan Chanhanga
- School of Nursing and Public Health, University of KwaZulu Natal, Durban, South Africa
| | - Tafadzwa Mindu
- School of Nursing and Public Health, University of KwaZulu Natal, Durban, South Africa
- Correspondence: Tafadzwa Mindu, Email
| | - John Mogaka
- School of Nursing and Public Health, University of KwaZulu Natal, Durban, South Africa
| | - Moses Chimbari
- School of Nursing and Public Health, University of KwaZulu Natal, Durban, South Africa
- Research and Innovation, Great Zimbabwe University, Masvingo, Zimbabwe
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3
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Wordofa M, Abera D, Mesfin A, Desta K, Taye B, Tsegaye A. Magnitude of Anemia and Undernutrition Among Primary School Children in a Setting of Mass Deworming in Central Ethiopia. Pediatric Health Med Ther 2022; 13:385-400. [PMID: 36606002 PMCID: PMC9809382 DOI: 10.2147/phmt.s381467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 12/22/2022] [Indexed: 01/01/2023] Open
Abstract
Background Undernutrition and anemia in children continue to be a public health problem in developing countries. Besides, intestinal parasitic infection among school children is common in developing countries. World Health Organization (WHO) recommends periodic deworming of children who live in endemic areas. The aim of this study was to determine the magnitude of anemia and undernutrition among school children in a setting of mass deworming. Methods A cross-sectional study was conducted among 510 school children aged 5-14 years from three randomly selected governmental schools in Sululta town, central Ethiopia. Socio-demographic variables were assessed using interviewer administered structured questionnaire. Anthropometric data were obtained and analyzed using WHO Anthroplusv1.0.4. Venous blood samples were collected using EDTA vacutainers. Hemoglobin level was determined by Sysmex KX-21N automated hematology analyzer and stool samples were processed using direct wet mount, formol-ether concentration and Kato-Katz methods. Data were entered and analyzed using SPSS version 21. Logistic regression analysis was performed to determine the association of anemia and undernutrition with the independent variables. Results The overall magnitude of anemia was 3.7%. Among anemic individuals, 84.2% and 15.8% of participants had mild and moderate anemia, respectively. The magnitude of stunting and thinness was 16.9% and 10.8%, respectively. Of them, 18.6% of stunting and 14.5% of thinness were severe. Of factors related to undernutrition, children from large families (≥5) were less likely to be stunted (AOR=0.38, 95% CI=0.2-0.7, P=0.002) compared to small families. Conclusion The magnitude of anemia in the study area was considered as an insignificant public health problem and none of the socio-demographic variables of participants were significantly associated with anemia and likewise with undernutrition except for family size. Further studies are required to clearly understand the impact of mass deworming on the magnitude of anemia and undernutrition.
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Affiliation(s)
- Moges Wordofa
- Addis Ababa University, College of Health Sciences, Department of Medical Laboratory Sciences, Addis Ababa, Ethiopia,Correspondence: Moges Wordofa, Addis Ababa University, College of Health Sciences, Department of Medical Laboratory Sciences, Addis Ababa, Ethiopia, Email
| | - Dessie Abera
- Addis Ababa University, College of Health Sciences, Department of Medical Laboratory Sciences, Addis Ababa, Ethiopia
| | | | - Kassu Desta
- Addis Ababa University, College of Health Sciences, Department of Medical Laboratory Sciences, Addis Ababa, Ethiopia
| | - Bineyam Taye
- Biology Department, Colgate University, Hamilton, NY, USA
| | - Aster Tsegaye
- Addis Ababa University, College of Health Sciences, Department of Medical Laboratory Sciences, Addis Ababa, Ethiopia
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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] [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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5
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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] [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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Wiegand RE, Secor WE, Fleming FM, French MD, King CH, Montgomery SP, Evans D, Utzinger J, Vounatsou P, de Vlas SJ. Control and Elimination of Schistosomiasis as a Public Health Problem: Thresholds Fail to Differentiate Schistosomiasis Morbidity Prevalence in Children. Open Forum Infect Dis 2021; 8:ofab179. [PMID: 34307724 PMCID: PMC8297701 DOI: 10.1093/ofid/ofab179] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 04/14/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Current World Health Organization guidelines utilize prevalence of heavy-intensity infections (PHIs), that is, ≥50 eggs per 10 mL of urine for Schistosoma haematobium and ≥400 eggs per gram of stool for S. mansoni, to determine whether a targeted area has controlled schistosomiasis morbidity or eliminated schistosomiasis as a public health problem. The relationship between these PHI categories and morbidity is not well understood. METHODS School-age participants enrolled in schistosomiasis monitoring and evaluation cohorts from 2003 to 2008 in Burkina Faso, Mali, Niger, Tanzania, Uganda, and Zambia were surveyed for infection and morbidity at baseline and after 1 and 2 rounds of preventive chemotherapy. Logistic regression was used to compare morbidity prevalence among participants based on their school's PHI category. RESULTS Microhematuria levels were associated with the S. haematobium PHI categories at all 3 time points. For any other S. haematobium or S. mansoni morbidity that was measured, PHI categories did not differentiate morbidity prevalence levels consistently. CONCLUSIONS These analyses suggest that current PHI categorizations do not differentiate the prevalence of standard morbidity markers. A reevaluation of the criteria for schistosomiasis control is warranted.
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Affiliation(s)
- Ryan E Wiegand
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - W Evan Secor
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | | | | | - Charles H King
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, USA
| | - Susan P Montgomery
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Darin Evans
- United States Agency for International Development, Washington, DC, USA
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Penelope Vounatsou
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Sake J de Vlas
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
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7
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Wiegand RE, Secor WE, Fleming FM, French MD, King CH, Deol AK, Montgomery SP, Evans D, Utzinger J, Vounatsou P, de Vlas SJ. Associations between infection intensity categories and morbidity prevalence in school-age children are much stronger for Schistosoma haematobium than for S. mansoni. PLoS Negl Trop Dis 2021; 15:e0009444. [PMID: 34033646 PMCID: PMC8183985 DOI: 10.1371/journal.pntd.0009444] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 06/07/2021] [Accepted: 05/04/2021] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND World Health Organization (WHO) guidelines for measuring global progress in schistosomiasis control classify individuals with Schistosoma spp. infections based on the concentration of excreted eggs. We assessed the associations between WHO infection intensity categories and morbidity prevalence for selected S. haematobium and S. mansoni morbidities in school-age children. METHODOLOGY A total of 22,488 children aged 6-15 years from monitoring and evaluation cohorts in Burkina Faso, Mali, Niger, Uganda, Tanzania, and Zambia from 2003-2008 were analyzed using Bayesian logistic regression. Models were utilized to evaluate associations between intensity categories and the prevalence of any urinary bladder lesion, any upper urinary tract lesion, microhematuria, and pain while urinating (for S. haematobium) and irregular hepatic ultrasound image pattern (C-F), enlarged portal vein, laboratory-confirmed diarrhea, and self-reported diarrhea (for S. mansoni) across participants with infection and morbidity data. PRINCIPAL FINDINGS S. haematobium infection intensity categories possessed consistent morbidity prevalence across surveys for multiple morbidities and participants with light infections had elevated morbidity levels, compared to negative participants. Conversely, S. mansoni infection intensity categories lacked association with prevalence of the morbidity measures assessed. CONCLUSIONS/SIGNIFICANCE Current status infection intensity categories for S. haematobium were associated with morbidity levels in school-age children, suggesting urogenital schistosomiasis morbidity can be predicted by an individual's intensity category. Conversely, S. mansoni infection intensity categories were not consistently indicative of childhood morbidity at baseline or during the first two years of a preventive chemotherapy control program.
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Affiliation(s)
- Ryan E. Wiegand
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - W. Evan Secor
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | | | | | - Charles H. King
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Arminder K. Deol
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Susan P. Montgomery
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Darin Evans
- United States Agency for International Development, Washington DC, United States of America
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Penelope Vounatsou
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Sake J. de Vlas
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
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8
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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] [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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9
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Anemia in preschool children from Angola: a review of the evidence. Porto Biomed J 2020; 5:e60. [PMID: 33299941 PMCID: PMC7722406 DOI: 10.1097/j.pbj.0000000000000060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 01/06/2020] [Indexed: 11/26/2022] Open
Abstract
Angola is one of the southern African countries with the highest prevalence of anemia, and despite the high geographic heterogeneity of its distribution across the country, it was reported to be indicative of a severe public health problem in some areas, mainly in children. Despite the relevance of this condition in the country there is still an important gap regarding scientific evidences and knowledge systematization in the indexed literature, that could be used to inform and optimize national public health policies willing to address it. Furthermore, the changes in anemia epidemiology among African preschool children and the late updates in nutrition-specific and nutrition-sensitive preventive strategies in the continent are of imperative relevance, as they could contribute to design context-specific national approaches to reduce anemia's morbidity and mortality. In this study we intent to perform a systematic review regarding the sparse evidence available on the country regarding the prevalence of anemia, its associated factors, the prevention, and/or control strategies with potential to reduce anemia that were implemented, and to discuss interventions targeting infections and/or nutrition conducted in other African countries.
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10
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Abudho BO, Guyah B, Ondigo BN, Ndombi EM, Ireri E, Carter JM, Riner DK, Kittur N, Karanja DMS, Colley DG. Evaluation of morbidity in Schistosoma mansoni-positive primary and secondary school children after four years of mass drug administration of praziquantel in western Kenya. Infect Dis Poverty 2020; 9:67. [PMID: 32539826 PMCID: PMC7296924 DOI: 10.1186/s40249-020-00690-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 06/08/2020] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND World Health Organization guidelines recommend preventive chemotherapy with praziquantel to control morbidity due to schistosomiasis. The primary aim of this cross-sectional study was to determine if 4 years of annual mass drug administration (MDA) in primary and secondary schools lowered potential markers of morbidity in infected children 1 year after the final MDA compared to infected children prior to initial MDA intervention. METHODS Between 2012 and 2016 all students in two primary and three secondary schools within three kilometers of Lake Victoria in western Kenya received annual mass praziquantel administration. To evaluate potential changes in morbidity we measured height, weight, mid-upper arm circumference, hemoglobin levels, abdominal ultrasound, and quality of life in children in these schools. This study compared two cross-sectional samples of Schistosoma mansoni egg-positive children: one at baseline and one at year five, 1 year after the fourth annual MDA. Data were analyzed for all ages (6-18 years old) and stratified by primary (6-12 years old) and secondary (12-18 years old) school groups. RESULTS The prevalence of multiple potential morbidity markers did not differ significantly between the egg-positive participants at baseline and those at 5 years by Mann Whitney nonparametric analysis and Fisher's exact test for continuous and categorical data, respectively. There was a small but significantly higher score in school-related quality of life assessment by year five compared to baseline by Mann Whitney analysis (P = 0.048) in 13-18 year olds where malaria-negative. However, anemia was not positively impacted by four annual rounds of MDA, but registered a significant negative outcome. CONCLUSIONS We did not detect differences in morbidity markers measured in a population of those infected or re-infected after multiple MDA. This could have been due to their relative insensitivity or a failure of MDA to prevent morbidity among those who remain infected. High malaria transmission in this area and/or a lack of suitable methods to measure the more subtle functional morbidities caused by schistosomiasis could be a factor. Further research is needed to identify and develop well-defined, easily quantifiable S. mansoni morbidity markers for this age group.
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Affiliation(s)
- Bernard O Abudho
- Centre for Global Health Research (KEMRI-CGHR), Kenya Medical Research Institute, Kisumu, Kenya.
- Department of Biomedical Sciences and Technology, Maseno University, Maseno, Kenya.
| | - Bernard Guyah
- Department of Biomedical Sciences and Technology, Maseno University, Maseno, Kenya
| | - Bartholomew N Ondigo
- Centre for Global Health Research (KEMRI-CGHR), Kenya Medical Research Institute, Kisumu, Kenya
- Department of Biochemistry and Molecular Biology, Egerton University, Nakuru, Kenya
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD, USA
| | - Eric M Ndombi
- Centre for Global Health Research (KEMRI-CGHR), Kenya Medical Research Institute, Kisumu, Kenya
- Department of Pathology, Kenyatta University, Nairobi, Kenya
| | - Edmund Ireri
- Centre for Clinical Research-Radiology Unit, Kenya Medical Research Institute, Nairobi, Kenya
| | - Jennifer M Carter
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA
| | - Diana K Riner
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA
| | - Nupur Kittur
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA
| | - Diana M S Karanja
- Centre for Global Health Research (KEMRI-CGHR), Kenya Medical Research Institute, Kisumu, Kenya
| | - Daniel G Colley
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA
- Department of Microbiology, University of Georgia, Athens, GA, USA
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11
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Impacts of host gender on Schistosoma mansoni risk in rural Uganda-A mixed-methods approach. PLoS Negl Trop Dis 2020; 14:e0008266. [PMID: 32401770 PMCID: PMC7219705 DOI: 10.1371/journal.pntd.0008266] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [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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12
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Amoah AS, Hoekstra PT, Casacuberta-Partal M, Coffeng LE, Corstjens PLAM, Greco B, van Lieshout L, Lim MD, Markwalter CF, Odiere MR, Reinhard-Rupp J, Roestenberg M, Stothard R, Tchuem Tchuenté LA, de Vlas SJ, van Dam GJ. Sensitive diagnostic tools and targeted drug administration strategies are needed to eliminate schistosomiasis. THE LANCET. INFECTIOUS DISEASES 2020; 20:e165-e172. [PMID: 32595046 DOI: 10.1016/s1473-3099(20)30254-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 03/03/2020] [Accepted: 03/23/2020] [Indexed: 11/29/2022]
Abstract
Although preventive chemotherapy has been instrumental in reducing schistosomiasis incidence worldwide, serious challenges remain. These problems include the omission of certain groups from campaigns of mass drug administration, the existence of persistent disease hotspots, and the risk of recrudescent infections. Central to these challenges is the fact that the diagnostic tools currently used to establish the burden of infection are not sensitive enough, especially in low-endemic settings, which results in underestimation of the true prevalence of active Schistosoma spp infections. This central issue necessitates that the current schistosomiasis control strategies recommended by WHO are re-evaluated and, possibly, adapted. More targeted interventions and novel approaches have been used to estimate the prevalence of schistosomiasis, such as establishing infection burden by use of precision mapping, which provides high resolution spatial information that delineates variations in prevalence within a defined geographical area. Such information is instrumental in guiding targeted intervention campaigns. However, the need for highly accurate diagnostic tools in such strategies is a crucial factor that is often neglected. The availability of highly sensitive diagnostic tests also opens up the possibility of applying strategies of sample pooling to reduce the cost of control programmes. To interrupt the transmission of, and eventually eliminate, schistosomiasis, better local targeting of preventive chemotherapy, in combination with highly sensitive diagnostic tools, is crucial.
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Affiliation(s)
- Abena S Amoah
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands; Department of Population Health, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK; Malawi Epidemiology and Intervention Research Unit, Chilumba, Malawi
| | - Pytsje T Hoekstra
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands.
| | | | - Luc E Coffeng
- Department of Public Health, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Paul L A M Corstjens
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands
| | | | - Lisette van Lieshout
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Mark D Lim
- Global Health Division, The Bill & Melinda Gates Foundation, Seattle, WA, USA; Global Public Health Programs, American Society for Microbiology, Washington DC, USA
| | - Christine F Markwalter
- Department of Chemistry, Vanderbilt University, Nashville, TN, USA; Duke Global Health Institute, Duke University, Durham, NC, USA
| | - Maurice R Odiere
- Neglected Tropical Diseases Unit, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | | | - Meta Roestenberg
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands; Department of Infectious Diseases, Leiden University Medical Center, Leiden, Netherlands
| | | | - Louis-Albert Tchuem Tchuenté
- Laboratory of Parasitology and Ecology, University of Yaoundé I, Yaoundé, Cameroon; Centre for Schistosomiasis and Parasitology, Yaoundé, Cameroon
| | - Sake J de Vlas
- Department of Public Health, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Govert J van Dam
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
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13
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Kittur N, King CH, Campbell CH, Kinung'hi S, Mwinzi PNM, Karanja DMS, N'Goran EK, Phillips AE, Gazzinelli-Guimaraes PH, Olsen A, Magnussen P, Secor WE, Montgomery SP, Utzinger J, Walker JW, Binder S, Colley DG. Persistent Hotspots in Schistosomiasis Consortium for Operational Research and Evaluation Studies for Gaining and Sustaining Control of Schistosomiasis after Four Years of Mass Drug Administration of Praziquantel. Am J Trop Med Hyg 2020; 101:617-627. [PMID: 31287046 PMCID: PMC6726953 DOI: 10.4269/ajtmh.19-0193] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Control of schistosomiasis presently relies largely on preventive chemotherapy with praziquantel through mass drug administration (MDA) programs. The Schistosomiasis Consortium for Operational Research and Evaluation has concluded five studies in four countries (Côte d’Ivoire, Kenya, Mozambique, and Tanzania) to evaluate alternative approaches to MDA. Studies involved four intervention years, with final evaluation in the fifth year. Mass drug administration given annually or twice over 4 years reduced average prevalence and intensity of schistosome infections, but not all villages that were treated in the same way responded similarly. There are multiple ways by which responsiveness to MDA, or the lack thereof, could be measured. In the analyses presented here, we defined persistent hotspots (PHS) as villages that achieved less than 35% reduction in prevalence and/or less than 50% reduction in infection intensity after 4 years of either school-based or community-wide MDA, either annually or twice in 4 years. By this definition, at least 30% of villages in each of the five studies were PHSs. We found no consistent relationship between PHSs and the type or frequency of intervention, adequacy of reported MDA coverage, and prevalence or intensity of infection at baseline. New research is warranted to identify PHSs after just one or a few rounds of MDA, and new adaptive strategies need to be advanced and validated for turning PHSs into responder villages.
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Affiliation(s)
- Nupur Kittur
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Charles H King
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio
| | - Carl H Campbell
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Safari Kinung'hi
- National Institute for Medical Research, Mwanza Research Centre, Mwanza, Tanzania
| | - Pauline N M Mwinzi
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Diana M S Karanja
- Neglected Tropical Diseases Branch, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Eliezer K N'Goran
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire.,Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire
| | - Anna E Phillips
- Department of Infectious Disease Epidemiology, London Centre for Neglected Tropical Disease Research, Imperial College London, London, United Kingdom
| | - Pedro H Gazzinelli-Guimaraes
- Department of Infectious Disease Epidemiology, Schistosomiasis Control Initiative, Imperial College London, London, United Kingdom
| | - Annette Olsen
- Section for Parasitology and Aquatic Pathobiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Pascal Magnussen
- Centre for Medical Parasitology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - W Evan Secor
- Parasitic Diseases Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Susan P Montgomery
- Parasitic Diseases Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Juerg Utzinger
- University of Basel, Basel, Switzerland.,Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Joseph W Walker
- Odum School of Ecology, University of Georgia, Athens, Georgia.,Department of Epidemiology, College of Public Health, University of Georgia, Athens, Georgia
| | - Sue Binder
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Daniel G Colley
- Department of Microbiology, University of Georgia, Athens, Georgia.,Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
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14
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Mutuku MW, Laidemitt MR, Beechler BR, Mwangi IN, Otiato FO, Agola EL, Ochanda H, Kamel B, Mkoji GM, Steinauer ML, Loker ES. A Search for Snail-Related Answers to Explain Differences in Response of Schistosoma mansoni to Praziquantel Treatment among Responding and Persistent Hotspot Villages along the Kenyan Shore of Lake Victoria. Am J Trop Med Hyg 2020; 101:65-77. [PMID: 31162012 PMCID: PMC6609173 DOI: 10.4269/ajtmh.19-0089] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Following a 4-year annual praziquantel (PZQ) treatment campaign, the resulting prevalence of Schistosoma mansoni was seen to differ among individual villages along the Kenyan shore of Lake Victoria. We have investigated possible inherent differences in snail-related aspects of transmission among such 10 villages, including six persistent hotspot (PHS) villages (≤ 30% reduction in prevalence following repeated treatments) located along the west-facing shore of the lake and four PZQ-responding (RESP) villages (> 30% prevalence reduction following repeated treatment) along the Winam Gulf. When taking into account all sampling sites, times, and water hyacinth presence/absence, shoreline-associated Biomphalaria sudanica from PHS and RESP villages did not differ in relative abundance or prevalence of S. mansoni infection. Water hyacinth intrusions were associated with increased B. sudanica abundance. The deeper water snail Biomphalaria choanomphala was significantly more abundant in the PHS villages, and prevalence of S. mansoni among villages both before and after control was positively correlated with B. choanomphala abundance. Worm recoveries from sentinel mice did not differ between PHS and RESP villages, and abundance of non-schistosome trematode species was not associated with S. mansoni abundance. Biomphalaria choanomphala provides an alternative, deepwater mode of transmission that may favor greater persistence of S. mansoni in PHS villages. As we found evidence for ongoing S. mansoni transmission in all 10 villages, we conclude that conditions conducive for transmission and reinfection occur ubiquitously. This argues for an integrated, basin-wide plan for schistosomiasis control to counteract rapid reinfections facilitated by large snail populations and movements of infected people around the lake.
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Affiliation(s)
- Martin W Mutuku
- School of Biological Sciences, College of Biological and Physical Sciences, University of Nairobi, Nairobi, Kenya.,Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - Martina R Laidemitt
- Department of Biology, Center for Evolutionary and Theoretical Immunology, Museum of Southwestern Biology, Parasitology Division, University of New Mexico, Albuquerque, New Mexico
| | - Brianna R Beechler
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, Oregon
| | - Ibrahim N Mwangi
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - Fredrick O Otiato
- Influenza Surveillance Program, Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Eric L Agola
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - Horace Ochanda
- School of Biological Sciences, College of Biological and Physical Sciences, University of Nairobi, Nairobi, Kenya
| | - Bishoy Kamel
- Department of Biology, Center for Evolutionary and Theoretical Immunology, Museum of Southwestern Biology, Parasitology Division, University of New Mexico, Albuquerque, New Mexico
| | - Gerald M Mkoji
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - Michelle L Steinauer
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon
| | - Eric S Loker
- Department of Biology, Center for Evolutionary and Theoretical Immunology, Museum of Southwestern Biology, Parasitology Division, University of New Mexico, Albuquerque, New Mexico
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15
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Amoani B, Adu B, Frempong MT, Sarkodie-Addo T, Victor Nuvor S, Abu EK, Harrison LM, Cappello M, Gyan B, Wilson MD. Cytokine profiles of Necator americanus and Plasmodium falciparum co-infected patients in rural Ghana. Cytokine X 2019; 1:100014. [PMID: 33604551 PMCID: PMC7885886 DOI: 10.1016/j.cytox.2019.100014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 08/21/2019] [Accepted: 08/28/2019] [Indexed: 12/20/2022] Open
Abstract
Co-infection of hookworm with P. falciparum modulates blood parasitemia levels. Cytokine levels were higher in the parasite infected individuals. Serum eotaxin level correlate negatively with hookworm intensity. Deworming drug treatment alters cytokine profiles in hookworm infected subjects.
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 responses.
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Affiliation(s)
- Benjamin Amoani
- Department of Biomedical Science, College of Health Sciences, University of Cape Coast, Cape Coast, Ghana.,Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana.,Molecular Medicine Department, School of Medical Sciences, Kwame Nkrumah University of Science and Technology, Ghana
| | - Bright Adu
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Margaret T Frempong
- Molecular Medicine Department, School of Medical Sciences, Kwame Nkrumah University of Science and Technology, Ghana
| | - Tracy Sarkodie-Addo
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Samuel Victor Nuvor
- Department of Microbiology, College of Health Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Emmanuel Kwasi Abu
- Department of Optometry, College of Health Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Lisa M Harrison
- Partnerships for Global Health, Department of Pediatrics, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Michael Cappello
- Partnerships for Global Health, Department of Pediatrics, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Ben Gyan
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Michael D Wilson
- Parasitology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
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16
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Smith C, McLachlan G, Al Shehri H, Adriko M, Arinaitwe M, Atuhaire A, Muheki Tukahebwa E, LaCourse EJ, Stanton M, Stothard JR, Bustinduy AL. Schistosoma mansoni Infection as a Predictor of Low Aerobic Capacity in Ugandan Children. Am J Trop Med Hyg 2019; 100:1498-1506. [PMID: 30994097 PMCID: PMC6553905 DOI: 10.4269/ajtmh.18-0922] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 02/19/2019] [Indexed: 12/20/2022] Open
Abstract
Using the 20-meter shuttle run test (20mSRT) as a morbidity metric, we assessed whether Schistosoma mansoni infection was associated with decreased aerobic capacity in Ugandan children across a range of altitudes, either at low (∼600 m) or high (∼1,000 m) altitudes. A total of 305 children were recruited from six schools within the Buliisa District, Lake Albert, Uganda. A subset (n = 96) of these had been previously assessed and treated for schistosomiasis ± malaria 2 weeks prior. Fitness scores on the 20mSRT were translated into VO2max using a standardized equation. Unadjusted and multivariable-adjusted analyses were performed using VO2max as the primary outcome. Analysis of fitness scores from 304 children, inclusive of the subset follow-up cohort, revealed a median VO2max of 45.4 mL kg-1 min-1 (interquartile range: 42.9-48.0 mL kg-1 min-1). Children residing at high altitudes demonstrated increased aerobic capacities (46.3 versus 44.8 mL kg-1 min-1, P = 0.031). The prevalence of stunting, wasting, S. mansoni egg patent infection, malaria, giardiasis, anemia, and fecal occult blood were 36.7%, 16.1%, 44.3%, 65.2%, 21.4%, 50.6%, and 41.2%, respectively. Median VO2max was elevated in those previously treated, compared with those newly recruited (46.3 versus 44 mL kg-1 min-1, P < 0.001). Multivariable-adjusted analysis revealed a strong negative association between S. mansoni egg patent infection and VO2max at low altitude (beta coefficient: -3.96, 95% CI: -6.56 to -137, P = 0.004). This is the first study to document a negative association between S. mansoni infection and aerobic capacity at low altitudes using the 20mSRT.
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Affiliation(s)
- Courtney Smith
- Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Georgia McLachlan
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Hajri Al Shehri
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Moses Adriko
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | - Moses Arinaitwe
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | - Aaron Atuhaire
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | | | - E. James LaCourse
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Michelle Stanton
- Lancaster Medical School, Lancaster University, Lancaster, United Kingdom
| | - J. Russell Stothard
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Amaya L. Bustinduy
- Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, United Kingdom
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17
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Al-Shehri H, Power BJ, Archer J, Cousins A, Atuhaire A, Adriko M, Arinaitwe M, Alanazi AD, LaCourse EJ, Kabatereine NB, Stothard JR. Non-invasive surveillance of Plasmodium infection by real-time PCR analysis of ethanol preserved faeces from Ugandan school children with intestinal schistosomiasis. Malar J 2019; 18:109. [PMID: 30935388 PMCID: PMC6444585 DOI: 10.1186/s12936-019-2748-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Accepted: 03/26/2019] [Indexed: 12/22/2022] Open
Abstract
Background As part of ongoing co-surveillance of intestinal schistosomiasis and malaria in Ugandan school children, a non-invasive detection method for amplification of Plasmodium DNA using real-time (rt)PCR analysis of ethanol preserved faeces (EPF) was assessed. For diagnostic tabulations, results were compared to rtPCR analysis of dried blood spots (DBS) and field-based point-of-care (POC) rapid diagnostic tests (RDTs). Methods A total of 247 school children from 5 primary schools along the shoreline of Lake Albert were examined with matched EPF and DBS obtained. Mean prevalence and prevalence by school was calculated by detection of Plasmodium DNA by rtPCR using a 18S rDNA Taqman® probe. Diagnostic sensitivity, specificity, positive and negative predictive values were tabulated and compared against RDTs. Results By rtPCR of EPF and DBS, 158 (63.9%; 95% CI 57.8–69.7) and 198 (80.1%, 95% CI 74.7–84.6) children were positive for Plasmodium spp. By RDT, 138 (55.8%; 95% CI 49.6–61.9) and 45 (18.2%; 95% CI 13.9–23.5) children were positive for Plasmodium falciparum, and with non-P. falciparum co-infections, respectively. Using RDT results as a convenient field-based reference, the sensitivity of rtPCR of EPF and DBS was 73.1% (95% CI 65.2–79.8) and 94.2% (95% CI 88.9–97.0) while specificity was 47.7% (95% CI 38.5–57.0) and 37.6% (95% CI 29.0–46.9), respectively. With one exception, school prevalence estimated by analysis of EPF was higher than that by RDT. Positive and negative predictive values were compared and discussed. Conclusions In this high transmission setting, EPF sampling with rtPCR analysis has satisfactory diagnostic performance in estimation of mean prevalence and prevalence by school upon direct comparison with POC-RDTs. Although analysis of EPF was judged inferior to that of DBS, it permits an alternative non-invasive sampling regime that could be implemented alongside general monitoring and surveillance for other faecal parasites. EPF analysis may also have future value in passive surveillance of low transmission settings.
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Affiliation(s)
- Hajri Al-Shehri
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK.,Ministry of Health, Asir District, Abha, Kingdom of Saudi Arabia
| | - B Joanne Power
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Sir Graeme Davies Building, 120 University Place, Glasgow, G12 8TA, UK
| | - John Archer
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Alice Cousins
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Aaron Atuhaire
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | - Moses Adriko
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | - Moses Arinaitwe
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | - Abdullah D Alanazi
- Department of Biological Science, Faculty of Science and Humanities, Shaqra University, Ad-Dawadimi, Saudi Arabia
| | - E James LaCourse
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | | | - J Russell Stothard
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK.
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Oboth P, Gavamukulya Y, Barugahare BJ. Prevalence and clinical outcomes of Plasmodium falciparum and intestinal parasitic infections among children in Kiryandongo refugee camp, mid-Western Uganda: a cross sectional study. BMC Infect Dis 2019; 19:295. [PMID: 30935405 PMCID: PMC6444856 DOI: 10.1186/s12879-019-3939-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 03/27/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The prevalence of Plasmodium falciparum and Intestinal Parasitic Infections (IPIs) - with the corresponding pathogenesis among children remain uncertain. This study aimed at determining the prevalence and the outcomes (including anaemia) of the respective infections and co-infections. Anaemia is a condition in which the number of red blood cells transporting oxygen to the various body parts is not sufficient to meet the needs of the body. METHODS This was a cross sectional study conducted among 476-refugee camp school children. Kato-Katz technique was used to screen stool samples for intestinal parasites. Microscopy was used for malaria testing while the portable Haemoglobin (Hb) calorimeter was used to measure haemoglobin concentration. RESULTS The overall prevalence of the mixed infections was 63.03%. Plasmodium falciparum was most prevalent of the single infections 262(55.04%) followed by Taenia spp. 14 (2.9%), Schistosoma mansoni 12(2.5%), Giardia lamblia 7 (2.9%), Trichuris trichiura 2(0.4%), Hookworm 2(0.4%) and Strongyloides stercoralis 1(0.2%). The odds of developing simple or uncomplicated malaria infection or anaemia was 14 times higher in individuals with dual co-infection with Plasmodium falciparum + Taenia sp. compared to single parasitic infection (Odds = 14.13, P = 0.019). Co-infection with Plasmodium falciparum + Taenia spp, was a strong predictor of Malaria and anaemia. CONCLUSION This study shows that Plasmodium falciparum and Taenia spp. co-infections is a stronger predictor of malaria and anaemia. The prevalence of malaria and anaemia remains higher than the other regions in Uganda outside restricted settlements. The findings of this study underline the need for pragmatic intervention programmes to reduce burden of the co-infections in the study area and similar settlements.
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Affiliation(s)
- Paul Oboth
- Department of Community and Public Health, Faculty of Health Sciences, Busitema University, P.O. Box, 1460, Mbale, Uganda
| | - Yahaya Gavamukulya
- Department of Biochemistry and Molecular Biology, Faculty of Health Sciences, Busitema University, P.O. Box, 1460, Mbale, Uganda
| | - Banson John Barugahare
- Department of Biology, Faculty of Science and Education, Busitema University, Tororo, Uganda
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Chisango TJ, Ndlovu B, Vengesai A, Nhidza AF, Sibanda EP, Zhou D, Mutapi F, Mduluza T. Benefits of annual chemotherapeutic control of schistosomiasis on the development of protective immunity. BMC Infect Dis 2019; 19:219. [PMID: 30832614 PMCID: PMC6398226 DOI: 10.1186/s12879-019-3811-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 02/13/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Schistosomiasis is a devastating parasitic disease. The mainstay of schistosomiasis control is by praziquantel treatment. The study aimed to determine benefits of annual chemotherapy of schistosomiasis on development of protective immunity in school children in a selected endemic rural area in Zimbabwe. METHODS Urine specimens from 212 school children (7-13 years) were collected and examined to determine prevalence, intensity and reinfection of S.haematobium at baseline, 6 weeks and 2 years following annual rounds of praziquantel treatment. Blood samples from the participants were assayed for total and S. haematobium (Sh13)-specific antibodies before and 2 years after annual rounds of treatment. RESULTS Annual treatment reduced the prevalence of S. haematobium infection (p < 0.05) from 23.1% at baseline to 0.47% after 2 years. Overall cure rate was 97.8%. Intensity of infection declined (p < 0.05) from 15.9 eggs/10 ml urine at baseline to 2 eggs/10 ml urine. After two years, overall rate of reinfection was 0.96%. At baseline, total IgG4 was higher in S. haematobium-infected children (p = 0.042) ,while all other immunoglobulins were within normal ranges. There was an increase in total IgG2 (p = 0.044) levels and a decrease in total IgG4 (p = 0.031) levels 2 years post-treatment; and no significant changes in other total immunoglobulins. Schistosoma-infected children at baseline showed an increase in anti-Sh13 IgG1 (p = 0.005) and a decrease in Sh13 IgG4 levels (p = 0.012) following treatment. CONCLUSION Annual praziquantel treatment delivered to school children over 2 years significantly reduce prevalence, intensity of infection and reinfection of S. haematobium infection. Treatment was also observed to cause a reduction in schistosome-specific blocking IgG4 and an increase in Schistosoma-specific protecting IgG1.
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Affiliation(s)
- Tawanda J Chisango
- School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Bongiwe Ndlovu
- School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Arthur Vengesai
- Biochemistry Department, University of Zimbabwe, 630 Churchill Ave, Mount Pleasant, Harare, Zimbabwe
| | - Agness Farai Nhidza
- School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Edson P Sibanda
- Scientific and Industrial Research and Development Centre, 1574 Alpes Road, Box, Harare, 6640, Zimbabwe
| | - Danai Zhou
- Medical Laboratory Sciences, College of Health Sciences, University of Zimbabwe, Harare, Zimbabwe
| | - Francisca Mutapi
- Institute of Immunology & Infection Research, University of Edinburgh, Ashworth Laboratories, King's Buildings, Charlotte Auerbach Road, Edinburgh, EH9 3FL, UK
| | - Takafira Mduluza
- School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa. .,Biochemistry Department, University of Zimbabwe, 630 Churchill Ave, Mount Pleasant, Harare, Zimbabwe.
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Repeated doses of Praziquantel in Schistosomiasis Treatment (RePST) - single versus multiple praziquantel treatments in school-aged children in Côte d'Ivoire: a study protocol for an open-label, randomised controlled trial. BMC Infect Dis 2018; 18:662. [PMID: 30547750 PMCID: PMC6295059 DOI: 10.1186/s12879-018-3554-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 11/23/2018] [Indexed: 11/30/2022] Open
Abstract
Background Large scale administration of the anthelminthic drug praziquantel (PZQ) to at-risk populations is the cornerstone of schistosomiasis control, although persisting high prevalence of infections in some areas and growing concerns of PZQ resistance have revealed the limitations of this strategy. Most studies assessing PZQ efficacy have used relatively insensitive parasitological diagnostics, such as the Kato-Katz (KK) and urine-filtration methods, thereby overestimating cure rates (CRs). This study aims to determine the efficacy of repeated PZQ treatments against Schistosoma mansoni infection in school-aged children in Côte d’Ivoire using the traditional KK technique, as well as more sensitive antigen- and DNA-detection methods. Methods An open-label, randomised controlled trial will be conducted in school-aged children (5 to 18 years) from the region of Taabo, Côte d’Ivoire, an area endemic for S. mansoni. This 8-week trial includes four two-weekly standard doses of PZQ in the “intense treatment” intervention group and one standard dose of PZQ in the “standard treatment” control group. The efficacy of PZQ will be evaluated in stool samples using the KK technique and real-time PCR as well as in urine using the point-of-care circulating cathodic antigen test and the up-converting phosphor, lateral flow, circulating anodic antigen assay. The primary outcome of the study will be the difference in CR of intense versus standard treatment with PZQ on individuals with a confirmed S. mansoni infection measured by KK. Secondary outcomes include the difference in CR and intensity reduction rate between the intense and standard treatment groups as measured by the other diagnostic tests, as well as the accuracy of the different diagnostic tests, and the safety of PZQ. Discussion This study will provide data on the efficacy of repeated PZQ treatment on the clearance of S. mansoni as measured by several diagnostic techniques. These findings will inform future mass drug administration policy and shed light on position of novel diagnostic tools to evaluate schistosomiasis control strategies. Trial registration The study is registered at EudraCT (2016–003017-10, date of registration: 22 July 2016) and (NCT02868385, date of registration: 16 August 2016). Electronic supplementary material The online version of this article (10.1186/s12879-018-3554-2) contains supplementary material, which is available to authorized users.
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De Neve JW, Andriantavison RL, Croke K, Krisam J, Rajoela VH, Rakotoarivony RA, Rambeloson V, Schultz L, Qamruddin J, Verguet S. Health, financial, and education gains of investing in preventive chemotherapy for schistosomiasis, soil-transmitted helminthiases, and lymphatic filariasis in Madagascar: A modeling study. PLoS Negl Trop Dis 2018; 12:e0007002. [PMID: 30589847 PMCID: PMC6307713 DOI: 10.1371/journal.pntd.0007002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 11/15/2018] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Neglected tropical diseases (NTDs) account for a large disease burden in sub-Saharan Africa. While the general cost-effectiveness of NTD interventions to improve health outcomes has been assessed, few studies have also accounted for the financial and education gains of investing in NTD control. METHODS We built on extended cost-effectiveness analysis (ECEA) methods to assess the health gains (e.g. infections, disability-adjusted life years or DALYs averted), household financial gains (out-of-pocket expenditures averted), and education gains (cases of school absenteeism averted) for five NTD interventions that the government of Madagascar aims to roll out nationally. The five NTDs considered were schistosomiasis, lymphatic filariasis, and three soil-transmitted helminthiases (Ascaris lumbricoides, Trichuris trichiura, and hookworm infections). RESULTS The estimated incremental cost-effectiveness for the roll-out of preventive chemotherapy for all NTDs jointly was USD125 per DALY averted (95% uncertainty range: 65-231), and its benefit-cost ratio could vary between 5 and 31. Our analysis estimated that, per dollar spent, schistosomiasis preventive chemotherapy, in particular, could avert a large number of infections (176,000 infections averted per $100,000 spent), DALYs (2,000 averted per $100,000 spent), and cases of school absenteeism (27,000 school years gained per $100,000 spent). CONCLUSION This analysis incorporates financial and education gains into the economic evaluation of health interventions, and therefore provides information about the efficiency of attainment of three Sustainable Development Goals (SDGs). Our findings reveal how the national scale-up of NTD control in Madagascar can help address health (SDG3), economic (SDG1), and education (SDG4) goals. This study further highlights the potentially large societal benefits of investing in NTD control in low-resource settings.
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Affiliation(s)
- Jan-Walter De Neve
- Institute of Global Health, Medical Faculty and University Hospital, Heidelberg University, Heidelberg, Germany
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston MA, United States of America
| | | | - Kevin Croke
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston MA, United States of America
- World Bank, Washington DC NW, Washington, DC, United States of America
| | - Johannes Krisam
- Institute of Medical Biometry and Informatics, Heidelberg University, Heidelberg, Germany
| | | | | | | | - Linda Schultz
- World Bank, Washington DC NW, Washington, DC, United States of America
| | - Jumana Qamruddin
- World Bank, Washington DC NW, Washington, DC, United States of America
| | - Stéphane Verguet
- Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston MA, United States of America
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Low Praziquantel Treatment Coverage for Schistosoma mansoni in Mayuge District, Uganda, Due to the Absence of Treatment Opportunities, Rather Than Systematic Non-Compliance. Trop Med Infect Dis 2018; 3:tropicalmed3040111. [PMID: 30297642 PMCID: PMC6306755 DOI: 10.3390/tropicalmed3040111] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 09/25/2018] [Accepted: 09/26/2018] [Indexed: 12/26/2022] Open
Abstract
The World Health Organization (WHO) recommends praziquantel mass drug administration (MDA) to control schistosomiasis in endemic regions. We aimed to quantify recent and lifetime praziquantel coverage, and reasons for non-treatment, at an individual level to guide policy recommendations to help Uganda reach WHO goals. Cross-sectional household surveys (n = 681) encompassing 3208 individuals (adults and children) were conducted in 2017 in Bugoto A and B, Mayuge District, Uganda. Participants were asked if they had received praziquantel during the recent MDA (October 2016) and whether they had ever received praziquantel in their lifetime. A multivariate logistic regression analysis with socio-economic and individual characteristics as covariates was used to determine factors associated with praziquantel uptake. In the MDA eligible population (≥5 years of age), the most recent MDA coverage was 48.8%. Across individuals’ lifetimes, 31.8% of eligible and 49.5% of the entire population reported having never taken praziquantel. Factors that improved individuals’ odds of taking praziquantel included school enrolment, residence in Bugoto B and increasing years of village-residency. Not being offered (49.2%) and being away during treatment (21.4%) were the most frequent reasons for not taking the 2016 praziquantel MDA. Contrary to expectations, chronically-untreated individuals were rarely systematic non-compliers, but more commonly not offered treatment.
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Wajja A, Namutebi M, Apule B, Oduru G, Kiwanuka S, Akello M, Nassanga B, Kabagenyi J, Mpiima J, Vermaak S, Lawrie A, Satti I, Verweij J, Cose S, Levin J, Kaleebu P, Tukahebwa E, McShane H, Elliott AM. Lessons from the first clinical trial of a non-licensed vaccine among Ugandan adolescents: a phase II field trial of the tuberculosis candidate vaccine, MVA85A. Wellcome Open Res 2018; 3:121. [PMID: 30687792 PMCID: PMC6338128 DOI: 10.12688/wellcomeopenres.14736.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/13/2018] [Indexed: 11/20/2022] Open
Abstract
Background: A more effective vaccine for tuberculosis (TB) is a global public health priority. Vaccines under development will always need evaluation in endemic settings, most of which have limited resources. Adolescents are an important target population for a new TB vaccine and for other vaccines which are relevant at school-age. However, in most endemic settings there is limited experience of trials of investigational products among adolescents, and adolescents are not routinely vaccinated. Methods: We used Modified vaccinia Ankara-expressing Ag85A (MVA85A), a well-tolerated candidate vaccine for tuberculosis, to assess the effect of Schistosoma mansoni infection on vaccine immunogenicity among Ugandan adolescents in primary school. We describe here the challenges and lessons learned in designing and implementing this first clinical trial among Ugandan adolescents using a non-licensed vaccine. Results: The school based immunization study was feasible and adhered to Good Clinical Practice principles. Engagement with the community and all stakeholders was critical for successful implementation of the trial. Creative and adaptable strategies were used to address protocol-specific, operational and logistical challenges. This study provided lessons and solutions that can be applied to other trials among adolescents in similar settings elsewhere, and to school-based immunization programs. Conclusion: Sufficient time and resources should be planned for community preparation and sensitization to ensure buy in and acceptance of a project of this kind. This trial shows that challenges to implementing early field trials in Africa are not insurmountable and that necessary well-planned high-quality ethical trials are feasible and should be encouraged. Trial Registration: ClinicalTrials.gov NCT02178748 03/06/2014.
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Affiliation(s)
- Anne Wajja
- MRC/UVRI and LSHTM Uganda Research Unit, Entebbe, Uganda
| | - Milly Namutebi
- MRC/UVRI and LSHTM Uganda Research Unit, Entebbe, Uganda
| | - Barbara Apule
- MRC/UVRI and LSHTM Uganda Research Unit, Entebbe, Uganda
| | - Gloria Oduru
- MRC/UVRI and LSHTM Uganda Research Unit, Entebbe, Uganda
| | | | - Mirriam Akello
- MRC/UVRI and LSHTM Uganda Research Unit, Entebbe, Uganda
| | | | | | - Juma Mpiima
- Vector Control Division, Ministry of Health of Uganda, Kampala, Uganda
| | - Samantha Vermaak
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Alison Lawrie
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Iman Satti
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Jaco Verweij
- Laboratory for Medical Microbiology and Immunology & Laboratory for Clinical Pathology,, St. Elisabeth Hospital, Tilburg, The Netherlands
| | - Stephen Cose
- MRC/UVRI and LSHTM Uganda Research Unit, Entebbe, Uganda
- Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, UK
| | - Jonathan Levin
- MRC/UVRI and LSHTM Uganda Research Unit, Entebbe, Uganda
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | | | - Edridah Tukahebwa
- Vector Control Division, Ministry of Health of Uganda, Kampala, Uganda
| | - Helen McShane
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Alison M Elliott
- MRC/UVRI and LSHTM Uganda Research Unit, Entebbe, Uganda
- Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, UK
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Adriko M, Tinkitina B, Tukahebw EM, Standley CJ, Stothard JR, Kabatereine NB. The epidemiology of schistosomiasis in Lango region Uganda 60 years after Schwetz 1951: Can schistosomiasis be eliminated through mass drug administration without other supportive control measures? Acta Trop 2018; 185:412-418. [PMID: 29935144 DOI: 10.1016/j.actatropica.2018.06.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 05/31/2018] [Accepted: 06/11/2018] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Lango region is the only known endemic region for urinary and intestinal schistosomiasis in Uganda. Although there has been no significant improvement in sanitation and safe water supply in the region over years, the endemicity and prevalence of Schistosoma haematobium, in particular, have declined, perhaps due to yearly mass treatment campaigns implemented since 2003. METHODS We report the epidemiology of Urinary and Intestinal schistosomiasis in Lango since 1951-2011 determined through Microscopic examinations for S. mansoni and S. haematobium respectively. A retrospective data review from 195 to 2011 was done to establish the prevalence over the years in the region. We performed Poisson regression analysis to observe trends in epidemiology before and after control was initiated in 2002. In addition, malacological surveys were undertaken in 2007 to assess local transmission potential. FINDINGS Contrary to earlier records, S. haematobium was low and confined to a few putative foci, with declined in infections from 28.2% in 1951 to 2.48% by 2011. Although this decline can be attributed to control, this was already much lower in 1967 than 1951, long before control interventions began suggesting that environmental changes may have made the habitat less suitable for the transmission of S. haematobium. Compared to the historical records S. mansoni prevalence first increased up immediately before control interventions in 2003, significantly declined (p=<0.001) until 2007. However, in 2007 and 2011 declined insignificant, (p = 0.656). No snail has ever been isolated shedding S. haematobium cercariae but many Bulinus snail spp. were found shedding S. bovis cercariae. CONCLUSION This suggests that a combination of environmental and mass treatment has had a significant impact on transmission in Lango region.
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Affiliation(s)
- M Adriko
- Vector Control Division, Ministry of Health, P.O. Box 1661, Plot 15 Bombo Road, Kampala, Uganda; Uganda Institute of Allied Health & Management Science (UIAHMS), School of Medical Entomology and Parasitology, P.O. Box 1661, Kampala, Uganda.
| | - B Tinkitina
- Vector Control Division, Ministry of Health, P.O. Box 1661, Plot 15 Bombo Road, Kampala, Uganda
| | - E M Tukahebw
- Vector Control Division, Ministry of Health, P.O. Box 1661, Plot 15 Bombo Road, Kampala, Uganda
| | - C J Standley
- Ecology & Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - J R Stothard
- Parasitology Department, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - N B Kabatereine
- Uganda Institute of Allied Health & Management Science (UIAHMS), School of Medical Entomology and Parasitology, P.O. Box 1661, Kampala, Uganda; Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, Imperial College London, St Mary's Campus, Norfolk Place, London W2 1PG, UK
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Ojja S, Kisaka S, Ediau M, Tuhebwe D, Kisakye AN, Halage AA, Mugambe RK, Mutyoba JN. Prevalence, intensity and factors associated with soil-transmitted helminths infections among preschool-age children in Hoima district, rural western Uganda. BMC Infect Dis 2018; 18:408. [PMID: 30119650 PMCID: PMC6098587 DOI: 10.1186/s12879-018-3289-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 07/31/2018] [Indexed: 01/20/2023] Open
Abstract
Background Over 80% of morbidity due to soil-transmitted helminthiasis (STH) occurs in low-income countries. Children under 5 account for 20–30% of the burden in endemic areas. This study assessed the prevalence, intensity and factors associated with STH infections among preschool-age children (PSAC) in Hoima district, Uganda. The PSAC are particularly vulnerable because the chronicity of this condition usually affects their physical and mental growth and development. Methods A cross-sectional study was carried out among 562 PSAC (1–5 years old) in 6 counties of Hoima district using Expanded Program on Immunization (EPI) method. Stool samples from children were examined using the formol ether concentration technique for STH egg detection. Egg counts were represented as egg per gram (EPG). A structured questionnaire was used to collect information on factors associated with STH infection. Generalized linear models were used to analyze relationships between STH infection and associated factors. Results Overall STH prevalence was 26.5%. Hookworm infection was the most prevalent (18.5%), followed by A.lumbricoides (9.8%) and T.trichiura (0.5%). Prevalence of STH infection was significantly higher in children aged 5 years (Pearson chi-square test, p = 0.009) than in children aged 1 year. The general geometric mean (GM) counts for Hookworm infection was (696.1 EPG; range (530.3–913.8)) with girls having a higher GM (789.8 EPG; range (120–13,200)) than boys. Eating uncooked or unwashed vegetables (adj. Prevalence Ratio (PR) = 1.9, 95% CI: 1.3–2.7) and fruits (adj.PR = 1.8, 95% CI: 1.1–2.8), indiscriminate disposal of young children’s faeces (adj.PR = 1.5, 95% CI: 1.1–2.0); not washing hands after defecation (adj.PR = 2.6, 95% CI: 1.9–3.6); and not deworming children regularly (adj.PR = 1.4, 95% CI: 1.1–1.8) were significantly associated with STH infection. Conclusion The prevalence of Soil transmitted helminths infection among preschool-age children in Hoima district significantly increased with age. Poor hygiene, inadequate sanitation and irregular deworming were associated with STH infections among PSAC in the study area. Intense health education on the importance of hygienic practices, improved sanitation and regular deworming of PSAC should be integrated into prevention and control programs. Electronic supplementary material The online version of this article (10.1186/s12879-018-3289-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Silvestro Ojja
- Department of Biostatistics and Epidemiology, Makerere University School of Public Health, Kampala, Uganda.
| | - Stevens Kisaka
- Department of Biostatistics and Epidemiology, Makerere University School of Public Health, Kampala, Uganda
| | - Michael Ediau
- Department of Health Policy Planning and Management, Makerere University School of Public Health, Kampala, Uganda
| | - Doreen Tuhebwe
- Department of Health Policy Planning and Management, Makerere University School of Public Health, Kampala, Uganda
| | - Angela N Kisakye
- Department of Health Policy Planning and Management, Makerere University School of Public Health, Kampala, Uganda
| | - Abdullah A Halage
- Department of Disease Control and Environmental Health, Makerere University School of Public Health, Kampala, Uganda
| | - Richard K Mugambe
- Department of Disease Control and Environmental Health, Makerere University School of Public Health, Kampala, Uganda
| | - Joan N Mutyoba
- Department of Biostatistics and Epidemiology, Makerere University School of Public Health, Kampala, Uganda
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Receiver operating characteristic curve analysis of four Aspergillus -specific IgG assays for the diagnosis of chronic pulmonary aspergillosis. Diagn Microbiol Infect Dis 2018; 91:47-51. [DOI: 10.1016/j.diagmicrobio.2018.01.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 12/08/2017] [Accepted: 01/01/2018] [Indexed: 12/20/2022]
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Salmon M, Salmon C, Masoda M, Salumu JM, Bozzi C, Nieburg P, Harrison LM, Humphries D, Abaca Uvon N, Wendel SK, Trout C, Cappello M. Albendazole Treatment Improves Work Capacity in Women Smallholder Farmers Infected with Hookworm: A Double-Blind Randomized Control Trial. Am J Trop Med Hyg 2018; 98:1419-1426. [PMID: 29611504 DOI: 10.4269/ajtmh.17-0403] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
An estimated 4.7 billion people live in regions exposed to soil-transmitted helminths, intestinal parasites that have significant impacts on the health of women smallholder farmers. The goal of this trial was to determine whether treatment with albendazole impacts the work capacity of these farmers. This is a prospective double-blind, randomized effectiveness trial. Participants (N = 250) were randomly selected from safe motherhood groups in the Democratic Republic of Congo. Prevalence/intensity of hookworm infection, hemoglobin, and demographics was obtained. At study (Time = 0), participants were randomized into treatment (albendazole 400 mg) and placebo (similar placebo tablet) groups. A step test was administered as a proxy metric for work capacity. Work capacity was defined as ∆heart rate before and after 3 minutes of step testing, in beats per minute. At study (time = 7 months), the step test was repeated and work capacity remeasured. The ∆work capacity (time = 0 minus time = 7 months) was the primary outcome. Investigators/field assistants were blinded to who was enrolled in groups, hookworm status, and step test results. Regression showed highly significant interactive effects of hookworm status and treatment group relative to ∆work capacity after controlling for resting pulse rate and age (P < 0.002). Estimated marginal means for work capacity (WC) for each of four groups (hookworm positive plus placebo, hookworm positive plus treatment, hookworm negative plus placebo, and hookworm negative plus treatment) showed women who were hookworm positive and received treatment decreased heart rate by 9.744 (95% confidence interval [CI]: 6.42, 13.07) beats per minute (increased WC), whereas women who were hookworm positive and received placebo saw a nonsignificant decrease of 0.034 (95% CI: -3.16, 3.84) beats per minute. Treatment with albendazole was associated with improved aerobic work capacity posttreatment. Given modest costs of drug distributions, risk benefits of periodic deworming warrants further study in larger controlled trials.
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Affiliation(s)
- Margaret Salmon
- InnovationCZ, San Francisco, California.,Global Health Emergency Medicine, University Health Network, University of Toronto, Toronto, Canada
| | | | - Maurice Masoda
- Health Education Action Leadership Africa Hospital, Goma, Democratic Republic of Congo
| | | | | | | | - Lisa M Harrison
- Yale Partnerships for Global Health, Yale School of Medicine, New Haven, Connecticut
| | | | - Naomi Abaca Uvon
- Programme National de Lutte contre l'Onchocercose, Ministry of Health, Kinshasa, Democratic Republic of Congo
| | - Sarah K Wendel
- Georgetown University Medical School, Washington, District of Columbia
| | - Clint Trout
- United States Agency for International Development, Yaoundé, Cameroon
| | - Michael Cappello
- Yale Partnerships for Global Health, Yale School of Medicine, New Haven, Connecticut.,Yale School of Public Health, New Haven, Connecticut
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Diet and hygiene practices influence morbidity in schoolchildren living in Schistosomiasis endemic areas along Lake Victoria in Kenya and Tanzania-A cross-sectional study. PLoS Negl Trop Dis 2018; 12:e0006373. [PMID: 29590175 PMCID: PMC5891076 DOI: 10.1371/journal.pntd.0006373] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 04/09/2018] [Accepted: 03/07/2018] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Since 2011, cohorts of schoolchildren in regions bordering Lake Victoria in Kenya and Tanzania have been investigated for morbidity caused by Schistosoma mansoni infection. Despite being neighbouring countries with similar lifestyles and ecological environments, Tanzanian schoolchildren had lower S. mansoni prevalence and intensity and they were taller and heavier, fewer were wasted and anaemic, and more were physical fit compared to their Kenyan peers. The aim of the present study was to evaluate whether diet and school-related markers of socioeconomic status (SES) could explain differences in morbidity beyond the effect of infection levels. METHODS AND PRINCIPAL FINDINGS Parasitological and morbidity data from surveys in 2013-2014 were compared with information on diet and school-related markers of SES collected in 2015 using questionnaires. A total of 490 schoolchildren (163 Kenyans and 327 Tanzanians) aged 9-11 years provided data. A higher proportion of Tanzanian pupils (69.4%, 95% CI: 64.3-74.5) knew where to wash hands after toilet visits compared to Kenyan pupils (48.5%, 95% CI: 40.9-56.1; P<0.0005). Similar proportions of children in the two countries ate breakfast, lunch and dinner, but the content of the meals differed. At all three meals, a higher proportion (95% CI) of Tanzanian pupils consumed animal proteins (mostly fish proteins) compared to their Kenyan peers (35.0% (28.3-41.7) vs. 0%; P<0.0005 at breakfast; 69.0% (63.9-74.1) vs. 43.6% (35.8-51.4); P<0.0005 at lunch; and 67.2% (62.1-72.3) vs. 53.4% (45.8-61.0); P = 0.003 at dinner). Multivariable analyses investigating risk factors for important morbidity markers among individuals revealed that after controlling for schistosome and malaria infections, eating animal proteins (fish) and knowing where to wash hands after toilet visits were significant predictors for both haemoglobin levels and physical fitness (measured as VO2 max). CONCLUSIONS These results suggest that the differences in morbidity may be affected by factors other than S. mansoni infection alone. Diet and hygiene practice differences were associated with health status of schoolchildren along Lake Victoria in Kenya and Tanzania. TRIAL REGISTRATION Trials Registration numbers: ISRCT 16755535 (Kenya), ISRCT 95819193 (Tanzania).
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Surveillance of intestinal schistosomiasis during control: a comparison of four diagnostic tests across five Ugandan primary schools in the Lake Albert region. Parasitology 2018; 145:1715-1722. [PMID: 29560841 PMCID: PMC6533640 DOI: 10.1017/s003118201800029x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Programmatic surveillance of intestinal schistosomiasis during control can typically use four diagnostic tests, either singularly or in combination, but these have yet to be cross-compared directly. Our study assembled a complete diagnostic dataset, inclusive of infection intensities, from 258 children from five Ugandan primary schools. The schools were purposely selected as typical of the endemic landscape near Lake Albert and reflective of high- and low-transmission settings. Overall prevalence was: 44.1% (95% CI 38.0–50.2) by microscopy of duplicate Kato-Katz smears from two consecutive stools, 56.9% (95% CI 50.8–63.0) by urine-circulating cathodic antigen (CCA) dipstick, 67.4% (95% CI 61.6–73.1) by DNA-TaqMan® and 75.1% (95% CI 69.8–80.4) by soluble egg antigen enzyme-linked immunosorbent assay (SEA-ELISA). A cross-comparison of diagnostic sensitivities, specificities, positive and negative predictive values was undertaken, inclusive of a latent class analysis (LCA) with a LCA-model estimate of prevalence by each school. The latter ranged from 9.6% to 100.0%, and prevalence by school for each diagnostic test followed a static ascending order or monotonic series of Kato-Katz, urine-CCA dipstick, DNA-TaqMan® and SEA-ELISA. We confirm that Kato-Katz remains a satisfactory diagnostic standalone in high-transmission settings but in low-transmission settings should be augmented or replaced by urine-CCA dipsticks. DNA-TaqMan® appears suitable in both endemic settings though is only implementable if resources permit. In low-transmission settings, SEA-ELISA remains the method of choice to evidence an absence infection. We discuss the pros and cons of each method concluding that future surveillance of intestinal schistosomiasis would benefit from a flexible, context-specific approach both in choice and application of each diagnostic method, rather than a single one-size fits all approach.
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Abudho BO, Ndombi EM, Guya B, Carter JM, Riner DK, Kittur N, Karanja DMS, Secor WE, Colley DG. Impact of Four Years of Annual Mass Drug Administration on Prevalence and Intensity of Schistosomiasis among Primary and High School Children in Western Kenya: A Repeated Cross-Sectional Study. Am J Trop Med Hyg 2018. [PMID: 29532768 PMCID: PMC5953387 DOI: 10.4269/ajtmh.17-0908] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Schistosomiasis remains a major public health problem in Kenya. The World Health Organization recommends preventive chemotherapy with praziquantel (PZQ) to control morbidity due to schistosomiasis. Morbidity is considered linked to intensity of infection, which along with prevalence is used to determine the frequency of mass drug administration (MDA) to school-age children. We determined the impact of annual school-based MDA on children across all primary and high school years using a repeated cross-sectional study design in five schools near Lake Victoria in western Kenya, an area endemic for Schistosoma mansoni. At baseline and for the following four consecutive years, between 897 and 1,440 school children in Grades 1-12 were enrolled and evaluated by Kato-Katz for S. mansoni and soil-transmitted helminths (STH), followed by annual MDA with PZQ and albendazole. Four annual rounds of MDA with PZQ were associated with reduced S. mansoni prevalence in all school children (44.7-14.0%; P < 0.001) and mean intensity of infection by 91% (90.4 to 8.1 eggs per gram [epg] of stool; P < 0.001). Prevalence of high-intensity infection (≥ 400 epg) decreased from 6.8% at baseline to 0.3% by the end of the study. Soil-transmitted helminth infections, already low at baseline, also decreased significantly over the years. In this high prevalence area, annual school-based MDA with high coverage across all Grades (1-12) resulted in rapid and progressive declines in overall prevalence and intensity of infection. This decrease was dramatic in regard to heavy infections in older school-attending children.
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Affiliation(s)
- Bernard O Abudho
- Department of Biomedical Sciences, School of Public Health, Maseno University, Maseno, Kenya.,Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Eric M Ndombi
- Department of Pathology, Kenyatta University, Nairobi, Kenya.,Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Bernard Guya
- Department of Biomedical Sciences, School of Public Health, Maseno University, Maseno, Kenya
| | - Jennifer M Carter
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Diana K Riner
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Nupur Kittur
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Diana M S Karanja
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - W Evan Secor
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Daniel G Colley
- Department of Microbiology, University of Georgia, Athens, Georgia.,Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
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Kittur N, Binder S, Campbell CH, King CH, Kinung'hi S, Olsen A, Magnussen P, Colley DG. Defining Persistent Hotspots: Areas That Fail to Decrease Meaningfully in Prevalence after Multiple Years of Mass Drug Administration with Praziquantel for Control of Schistosomiasis. Am J Trop Med Hyg 2017; 97:1810-1817. [PMID: 29016344 PMCID: PMC5805060 DOI: 10.4269/ajtmh.17-0368] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Preventive chemotherapy with praziquantel for schistosomiasis morbidity control is commonly done by mass drug administration (MDA). MDA regimen is usually based on prevalence in a given area, and effectiveness is evaluated by decreases in prevalence and/or intensity of infection after several years of implementation. Multiple studies and programs now find that even within well-implemented, multiyear, annual MDA programs there often remain locations that do not decline in prevalence and/or intensity to expected levels. We term such locations “persistent hotspots.” To study and address persistent hotspots, investigators and neglected tropical disease (NTD) program managers need to define them based on changes in prevalence and/or intensity. But how should the data be analyzed to define a persistent hotspot? We have analyzed a dataset from an operational research study in western Tanzania after three annual MDAs using four different approaches to define persistent hotspots. The four approaches are 1) absolute percent change in prevalence; 2) percent change in prevalence; 3) change in World Health Organization guideline categories; 4) change (absolute or percent) in both prevalence and intensity. We compare and contrast the outcomes of these analyses. Our intent is to show how the same dataset yields different numbers of persistent hotspots depending on the approach used to define them. We suggest that investigators and NTD program managers use the approach most suited for their study or program, but whichever approach is used, it should be clearly stated so that comparisons can be made within and between studies and programs.
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Affiliation(s)
- Nupur Kittur
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, Georgia
| | - Sue Binder
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, Georgia
| | - Carl H Campbell
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, Georgia
| | - Charles H King
- Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, Ohio.,Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, Georgia
| | - Safari Kinung'hi
- National Institute for Medical Research (NIMR), Mwanza Centre, Mwanza, Tanzania
| | - Annette Olsen
- Parasitology and Aquatic Diseases, Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Pascal Magnussen
- Department of Veterinary and Animal Sciences, Section for Parasitology and Aquatic Diseases, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Immunology and Microbiology, Centre for Medical Parasitology, University of Copenhagen, Copenhagen, Denmark
| | - Daniel G Colley
- Department of Microbiology, University of Georgia, Athens, Georgia.,Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, Georgia
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Musuva R, Shen Y, Wei X, Binder S, Ivy JA, Secor WE, Montgomery SP, King CH, Mwinzi PNM. Change in children's school behavior after mass administration of praziquantel for Schistosoma mansoni infection in endemic areas of western Kenya: A pilot study using the Behavioral Assessment System for Children (BASC-2). PLoS One 2017; 12:e0181975. [PMID: 28746403 PMCID: PMC5528892 DOI: 10.1371/journal.pone.0181975] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 07/10/2017] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Schistosomiasis is a parasite-related chronic inflammatory condition that can cause anemia, decreased growth, liver abnormalities, and deficits in cognitive functioning among children. METHODOLOGY/PRINCIPAL FINDINGS This study used the Behavior Assessment System for Children (BASC-2) to collect data on thirty-six 9-12 year old school-attending children's behavioral profiles in an Schistosoma mansoni-endemic area of western Kenya, before and after treatment with praziquantel for S. mansoni infection. BASC-2 T scores were significantly reduced post-treatment (p < 0.05) for each of the 'negative' behavior categories including externalizing problems (hyperactivity, aggression, and conduct problems that are disruptive in nature), internalizing problems (anxiety, depression, somatization, atypicality, and withdrawal), school problems (academic difficulties, included attention problems and learning problems), and the composite behavioral symptoms index (BSI), signifying improved behavior. While the observed improvement in the 'positive' behavior category of adaptive skills (adaptability, functional communication, social skills, leadership, and study skills) was not statistically significant, there were significant improvements in two adaptive skills subcategories: social skills and study skills. CONCLUSION/SIGNIFICANCE Results of this study suggest that children have better school-related behaviors without heavy S. mansoni infection, and that infected children's behaviors, especially disruptive problem behaviors, improve significantly after praziquantel treatment.
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Affiliation(s)
- Rosemary Musuva
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Ye Shen
- Department of Epidemiology & Biostatistics, University of Georgia, Athens, Georgia, United States of America
| | - Xianjue Wei
- Department of Epidemiology & Biostatistics, University of Georgia, Athens, Georgia, United States of America
| | - Sue Binder
- Schistosomiasis Consortium for Operational Research and Evaluation, University of Georgia, Athens, Georgia, United States of America
| | - Julianne A. Ivy
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - W. Evan Secor
- Parasitic Diseases Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Susan P. Montgomery
- Parasitic Diseases Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Charles H. King
- Schistosomiasis Consortium for Operational Research and Evaluation, University of Georgia, Athens, Georgia, United States of America
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Pauline N. M. Mwinzi
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
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Legason ID, Atiku A, Ssenyonga R, Olupot-Olupot P, Barugahare JB. Prevalence of Anaemia and Associated Risk Factors among Children in North-western Uganda: A Cross Sectional Study. BMC HEMATOLOGY 2017; 17:10. [PMID: 28680644 PMCID: PMC5496358 DOI: 10.1186/s12878-017-0081-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 06/14/2017] [Indexed: 11/24/2022]
Abstract
Background Despite the public health significance of anaemia in African children, its broader and often preventable risk factors remain largely under described. This study investigated, for the first time, the prevalence of childhood anaemia and its risk factors in an urban setting in Uganda. Methods A total of 342 children were enrolled. Venous blood samples were collected in EDTA tubes and analyzed using Symex 500i (Symex Corp. Japan). Stool and urine samples were analyzed according to established standard methods. Anthropometric indicators were calculated according to the CDC/WHO 1978 references. Ethical approval was granted. Results Categorically, the prevalence of anaemia was; 37.2, 33.3 and 11.8% among children aged 1–5 years, 6–11 years and 12–14 years respectively. Overall anaemia prevalence was 34.4%. The risk of anaemia was higher among males than females [(OR = 1.3, 95% CI = 0.8, 2.1), P = .22]. Malaria was associated with a 1.5 times risk of anaemia though not statistically significant in the multivariate analysis (P = .19). Maternal parity <5 (P = .002), and stunting [(OR = 2.5, 95% CI = 1.3, 4.7), P = .004] were positively associated with anaemia. There was a positive correlation between household size and income (Pearson X2 = 22.96; P = .001), implying that large families were of higher socioeconomic status. Conclusions This study demonstrates that anaemia is more prevalent in the under-5 age. The risk factors are stunting and low maternal parity. Interventions that address nutritional deficiencies in both pre-school and school children are recommended. Malaria and helminthiasis control measures counter the risk of anaemia. Further studies are required to investigate the association between maternal parity and anaemia found in this study.
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Affiliation(s)
| | | | - Ronald Ssenyonga
- School of Public Health, Makerere College of Health Sciences, Kampala, Uganda
| | | | - John Banson Barugahare
- School of Postgraduate Studies, Uganda Christian University, Mukono, Uganda.,Faculty of Science and Education, Busitema University, Tororo, Uganda
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Lamberton PHL, Faust CL, Webster JP. Praziquantel decreases fecundity in Schistosoma mansoni adult worms that survive treatment: evidence from a laboratory life-history trade-offs selection study. Infect Dis Poverty 2017. [PMID: 28622767 PMCID: PMC5472905 DOI: 10.1186/s40249-017-0324-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Background Mass drug administration of praziquantel is the World Health Organization’s endorsed control strategy for schistosomiasis. A decade of annual treatments across sub-Saharan Africa has resulted in significant reductions of infection prevalence and intensity levels, although ‘hotspots’ remain. Repeated drug treatments place strong selective pressures on parasites, which may affect life-history traits that impact transmission dynamics. Understanding drug treatment responses and the evolution of such traits can help inform on how to minimise the risk of drug resistance developing, maximise sustainable control programme success, and improve diagnostic protocols. Methods We performed a four-generation Schistosoma mansoni praziquantel selection experiment in mice and snails. We used three S. mansoni lines: a praziquantel-resistant isolate (R), a praziquantel-susceptible isolate (S), and a co-infected line (RS), under three treatment regimens: untreated, 25 mg/kg praziquantel, or 50 mg/kg praziquantel. Life-history traits, including parasite adult-worm establishment, survival, reproduction (fecundity), and associated morbidity, were recorded in mice across all four generations. Predictor variables were tested in a series of generalized linear mixed effects models to determine which factors had a significant influence on parasite life-history traits in definitive hosts under different selection regimes. Results Praziquantel pressure significantly reduced adult-worm burdens across all generations and isolates, including within R-lines. However, previous drug treatment resulted in an increase in adult-worm establishment with increasing generation from P1 to F3. The highest worm numbers were in the co-infected RS line. Praziquantel treatment decreased adult-worm burden, but had a larger negative impact on the mean daily number of miracidia, a proxy for fecundity, across all three parasite isolates. Conclusions Our predicted cost of resistance was not supported by the traits we measured within the murine host. We did not find evidence for negative adult worm density-dependent effects on fecundity. In contrast, of the adult worms that survived treatment, even low doses of praziquantel significantly reduced adult-worm fecundity. Such reductions in worm fecundity post treatment suggest that egg - based measures of drug efficacy, such as Kato-Katz, may overestimate the short-term effect of praziquantel on adult - worm burdens. These findings have important implications for S. mansoni transmission control, diagnostic protocols, and the potential for undetected selection toward drug resistance. Electronic supplementary material The online version of this article (doi:10.1186/s40249-017-0324-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Poppy H L Lamberton
- Institute for Biodiversity, Animal Health, and Comparative Medicine & Wellcome Centre for Molecular Parasitology, College of Medical, Veterinary & Life Sciences, University of Glasgow, G12 8QQ, Glasgow, UK. .,London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, St Mary's Campus, W2 1PG, London, UK.
| | - Christina L Faust
- Institute for Biodiversity, Animal Health, and Comparative Medicine & Wellcome Centre for Molecular Parasitology, College of Medical, Veterinary & Life Sciences, University of Glasgow, G12 8QQ, Glasgow, UK
| | - Joanne P Webster
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, St Mary's Campus, W2 1PG, London, UK.,Centre for Endemic, Emerging and Exotic Diseases, The Royal Veterinary College, University of London, London, AL9 7TA, UK
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35
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Wajja A, Kizito D, Nassanga B, Nalwoga A, Kabagenyi J, Kimuda S, Galiwango R, Mutonyi G, Vermaak S, Satti I, Verweij J, Tukahebwa E, Cose S, Levin J, Kaleebu P, Elliott AM, McShane H. The effect of current Schistosoma mansoni infection on the immunogenicity of a candidate TB vaccine, MVA85A, in BCG-vaccinated adolescents: An open-label trial. PLoS Negl Trop Dis 2017; 11:e0005440. [PMID: 28472067 PMCID: PMC5417418 DOI: 10.1371/journal.pntd.0005440] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 02/27/2017] [Indexed: 02/03/2023] Open
Abstract
INTRODUCTION Helminth infection may affect vaccine immunogenicity and efficacy. Adolescents, a target population for tuberculosis booster vaccines, often have a high helminth burden. We investigated effects of Schistosoma mansoni (Sm) on the immunogenicity and safety of MVA85A, a model candidate tuberculosis vaccine, in BCG-vaccinated Ugandan adolescents. METHODS In this phase II open label trial we enrolled 36 healthy, previously BCG-vaccinated adolescents, 18 with no helminth infection detected, 18 with Sm only. The primary outcome was immunogenicity measured by Ag85A-specific interferon gamma ELISpot assay. Tuberculosis and schistosome-specific responses were also assessed by whole-blood stimulation and multiplex cytokine assay, and by antibody ELISAs. RESULTS Ag85A-specific cellular responses increased significantly following immunisation but with no differences between the two groups. Sm infection was associated with higher pre-immunisation Ag85A-specific IgG4 but with no change in antibody levels following immunisation. There were no serious adverse events. Most reactogenicity events were of mild or moderate severity and resolved quickly. CONCLUSIONS The significant Ag85A-specific T cell responses and lack of difference between Sm-infected and uninfected participants is encouraging for tuberculosis vaccine development. The implications of pre-existing Ag85A-specific IgG4 antibodies for protective immunity against tuberculosis among those infected with Sm are not known. MVA85A was safe in this population. TRIAL REGISTRATION ClinicalTrials.gov NCT02178748.
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Affiliation(s)
- Anne Wajja
- Co-infection Studies Program, MRC/UVRI Uganda Research Unit, Entebbe, Uganda
| | - Dennison Kizito
- Co-infection Studies Program, MRC/UVRI Uganda Research Unit, Entebbe, Uganda
| | - Beatrice Nassanga
- Co-infection Studies Program, MRC/UVRI Uganda Research Unit, Entebbe, Uganda
| | - Angela Nalwoga
- Co-infection Studies Program, MRC/UVRI Uganda Research Unit, Entebbe, Uganda
| | - Joyce Kabagenyi
- Co-infection Studies Program, MRC/UVRI Uganda Research Unit, Entebbe, Uganda
| | - Simon Kimuda
- Co-infection Studies Program, MRC/UVRI Uganda Research Unit, Entebbe, Uganda
| | - Ronald Galiwango
- Co-infection Studies Program, MRC/UVRI Uganda Research Unit, Entebbe, Uganda
| | - Gertrude Mutonyi
- Co-infection Studies Program, MRC/UVRI Uganda Research Unit, Entebbe, Uganda
| | - Samantha Vermaak
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Iman Satti
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Jaco Verweij
- Laboratory for Medical Microbiology and Immunology & Laboratory for Clinical Pathology, St. Elisabeth Hospital, Tilburg, The Netherlands
| | | | - Stephen Cose
- Co-infection Studies Program, MRC/UVRI Uganda Research Unit, Entebbe, Uganda
- London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Jonathan Levin
- Co-infection Studies Program, MRC/UVRI Uganda Research Unit, Entebbe, Uganda
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Pontiano Kaleebu
- Co-infection Studies Program, MRC/UVRI Uganda Research Unit, Entebbe, Uganda
| | - Alison M. Elliott
- Co-infection Studies Program, MRC/UVRI Uganda Research Unit, Entebbe, Uganda
- London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Helen McShane
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
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Abstract
Early in the history of schistosomiasis research, children under 5 years of age were known to be infected. Although this problem was recognized over 100 years ago, insufficient action has been taken to address this issue. Under current policy, such infected children only receive their first antiparasitic treatment (praziquantel - PZQ) upon entry into primary school as current mass drug administration programmes typically target school-aged children. For many infected children, they will wait up to 6 years before receiving their first medication and significant schistosomiasis-related morbidity may have already established. This inequity would not be accepted for other diseases. To unveil some of the reasons behind this neglect, it is paramount to understand the intricate historical relationship between schistosomiasis and British Imperial medicine, to underline its lasting influence on today's public health priorities. This review presents a perspective on the historical neglect of paediatric schistosomiasis, focusing on important gaps that persist from the early days after discovery of this parasite. Looking to end this inequity, we address several issues that need to be overcome to move forward towards the lasting success of schistosomiasis control and elimination efforts.
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Simoonga C, Kazembe LN. Using the hierarchical ordinal regression model to analyse the intensity of urinary schistosomiasis infection in school children in Lusaka Province, Zambia. Infect Dis Poverty 2017; 6:43. [PMID: 28219411 PMCID: PMC5319044 DOI: 10.1186/s40249-017-0262-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 02/16/2017] [Indexed: 12/19/2022] Open
Abstract
Background Urinary schistosomiasis has been a major public health problem in Zambia for many years. However, the disease profile may vary in different locale due to the changing ecosystem that contributes to the risk of acquiring the disease. The objective of this study was to quantify risk factors associated with the intensity of urinary schistosomiasis infection in school children in Lusaka Province, Zambia, in order to better understand local transmission. Methods Data were obtained from 1 912 school children, in 20 communities, in the districts of Luangwa and Kafue in Lusaka Province. Both individual- and community-level covariates were incorporated into an ordinal logistic regression model to predict the probability of an infection being a certain intensity in a three-category outcome response: 0 = no infection, 1 = light infection, and 2 = moderate/heavy infection. Random effects were introduced to capture unobserved heterogeneity. Results Overall, the risk of urinary schistosomiasis was strongly associated with age, altitude at which the child lived, and sex. Weak associations were observed with the normalized difference vegetation index, maximum temperature, and snail abundance. Detailed analysis indicated that the association between infection intensities and age and altitude were category-specific. Particularly, infection intensity was lower in children aged between 5 and 9 years compared to those aged 10 to 15 years (OR = 0.72, 95% CI = 0.51–0.99). However, the age-specific risk changed at different levels of infection, such that when comparing children with light infection to those who were not infected, age was associated with a lower odds (category 1 vs category 0: OR = 0.71, 95% CI: 0.50–0.99), yet such a relation was not significant when considering children who were moderately or heavily infected compared to those with a light or no infection (category 2 vs category 0: OR = 0.96, 95% CI: 0.45–1.64). Overall, we observed that children living in the valley were less likely to acquire urinary schistosomiasis compared to those living in plateau areas (OR = 0.48, 95% CI: 0.16–0.71). However, category-specific effects showed no significant association in category 1 (light infection), whereas in category 2 (moderate/high infection), the risk was still significantly lower for those living in the valley compared to those living in plateau areas (OR = 0.18, 95% CI: 0.04–0.75). Conclusions This study demonstrates the importance of understanding the dynamics and heterogeneity of infection in control efforts, and further suggests that apart from the well-researched factors of Schistosoma intensity, various other factors influence transmission. Control programmes need to take into consideration the varying infection intensities of the disease so that effective interventions can be designed. Electronic supplementary material The online version of this article (doi:10.1186/s40249-017-0262-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Christopher Simoonga
- Ministry of Health, Ndeke House, Haile Selassie Avenue, P.O. Box 30205, Lusaka, Zambia
| | - Lawrence N Kazembe
- Mathematical Sciences Department, Chancellor College, University of Malawi, P.O. Box 280, Zomba, Malawi. .,Statistics and Population Studies Department, University of Namibia, Private Bag 13301, Windhoek, Namibia.
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Andrade G, Bertsch DJ, Gazzinelli A, King CH. Decline in infection-related morbidities following drug-mediated reductions in the intensity of Schistosoma infection: A systematic review and meta-analysis. PLoS Negl Trop Dis 2017; 11:e0005372. [PMID: 28212414 PMCID: PMC5333910 DOI: 10.1371/journal.pntd.0005372] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Revised: 03/02/2017] [Accepted: 01/30/2017] [Indexed: 11/21/2022] Open
Abstract
Background Since 1984, WHO has endorsed drug treatment to reduce Schistosoma infection and its consequent morbidity. Cross-sectional studies suggest pre-treatment correlation between infection intensity and risk for Schistosoma-related pathology. However, evidence also suggests that post-treatment reduction in intensity may not reverse morbidity because some morbidities occur at all levels of infection, and some reflect permanent tissue damage. The aim of this project was to systematically review evidence on drug-based control of schistosomiasis and to develop a quantitative estimate of the impact of post-treatment reductions in infection intensity on prevalence of infection-associated morbidity. Methodology/Principal findings This review was registered at inception with PROSPERO (CRD42015026080). Studies that evaluated morbidity before and after treatment were identified by online searches and searches of private archives. Post-treatment odds ratios or standardized mean differences were calculated for each outcome, and these were correlated to treatment-related egg count reduction ratios (ERRs) by meta-regression. A greater ERR correlated with greater reduction in odds of most morbidities. Random effects meta-analysis was used to derive summary estimates: after treatment of S. mansoni and S. japonicum, left-sided hepatomegaly was reduced by 54%, right-sided hepatomegaly by 47%, splenomegaly by 37%, periportal fibrosis by 52%, diarrhea by 53%, and blood in stools by 75%. For S. haematobium, hematuria was reduced by 92%, proteinuria by 90%, bladder lesions by 86%, and upper urinary tract lesions by 72%. There were no consistent changes in portal dilation or hemoglobin levels. In sub-group analysis, age, infection status, region, parasite species, and interval to follow-up were associated with meaningful differences in outcome. Conclusion/Significance While there are challenges to implementing therapy for schistosomiasis, and praziquantel therapy is not fully curative, reductions in egg output are significantly correlated with decreased morbidity and can be used to project diminution in disease burden when contemplating more aggressive strategies to minimize infection intensity. Schistosomiasis is the disease caused by infection with Schistosoma parasitic flukes. Depending on the infecting species, chronic Schistosoma infection can cause a variety of pathologies including liver and spleen enlargement, fibrosis and hypertension of the portal vein of the liver, or bladder ulceration and deformities and kidney blockage. Infection can also cause anemia, diarrhea, abdominal pain, and decreased physical fitness. In our study, we quantified the reductions in prevalence of infection-related morbidities among populations with Schistosoma infection, as achieved by giving one or more drug treatments. We systematically reviewed 71 available reports of Schistosoma-related morbidity reduction and determined, based on a meta-analysis of the primary data, that the odds of persisting morbidity progressively decrease when greater post-treatment reductions in parasite burden are achieved, as reflected by reduced egg counts in standard diagnostic testing. This suggests that repeated or more effective anti-parasite drug treatment will be a valuable tool for greater reduction of Schistosoma-related patient morbidities in affected areas.
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Affiliation(s)
- Gisele Andrade
- Escola de Enfermagem, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - David J. Bertsch
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Andrea Gazzinelli
- Escola de Enfermagem, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
- Instituto Nacional de Ciência e Tecnologia em Doenças Tropicais (INCT-DT), Belo Horizonte, MG, Brazil
| | - Charles H. King
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, United States of America
- Schistosomiasis Consortium for Operational Research and Evaluation, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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Stanton MC, Adriko M, Arinaitwe M, Howell A, Davies J, Allison G, LaCourse EJ, Muheki E, Kabatereine NB, Stothard JR. Intestinal schistosomiasis in Uganda at high altitude (>1400 m): malacological and epidemiological surveys on Mount Elgon and in Fort Portal crater lakes reveal extra preventive chemotherapy needs. Infect Dis Poverty 2017; 6:34. [PMID: 28162096 PMCID: PMC5292801 DOI: 10.1186/s40249-017-0248-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 01/19/2017] [Indexed: 01/24/2023] Open
Abstract
Background Intestinal schistosomiasis is of public health importance in Uganda but communities living above 1400 m are not targeted for control as natural transmission is thought unlikely. To assess altitudinal boundaries and at-risk populations, conjoint malacological and epidemiological surveys were undertaken on Mount Elgon (1139 m–3937 m), in Fort Portal crater lakes and in the Rwenzori Mountains (1123 m–4050 m). Methods Seventy freshwater habitats [Mount Elgon (37), Fort Portal crater lakes (23), Rwenzori Mountains (8) and Lake Albert (2)] were inspected for Biomphalaria species. Water temperature, pH and conductivity were recorded. A parasitological examination of 756 schoolchildren [Mount Elgon (300), Fort Portal crater lakes (456)] by faecal microscopy of duplicate Kato-Katz smears from two consecutive stool samples was bolstered by antigen (urine-CCA dipstick) and antibody (SEA-ELISA) diagnostic assays. Results Biomphalaria spp. was found up to 1951 m on Mount Elgon and 1567 m in the Fort Portal crater lakes. Although no snail from Mount Elgon shed cercariae, molecular analysis judged 7.1% of snails sampled at altitudes above 1400 m as having DNA of Schistosoma mansoni; in Fort Portal crater lakes three snails shed schistosome cercariae. Prevalence of intestinal schistosomiasis as measured in schoolchildren by Kato-Katz (Mount Elgon = 5.3% v. Fort Portal crater lakes = 10.7%), CCA urine-dipsticks (18.3% v. 34.4%) and SEA-ELISA (42.3% v. 63.7%) showed negative associations with increasing altitude with some evidence of infection up to 2000 m. Conclusions Contrary to expectations, these surveys clearly show that natural transmission of intestinal schistosomiasis occurs above 1400 m, possibly extending up to 2000 m. Using spatial epidemiological predictions, this now places some extra six million people at-risk, denoting an expansion of preventive chemotherapy needs in Uganda. Electronic supplementary material The online version of this article (doi:10.1186/s40249-017-0248-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Michelle C Stanton
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Moses Adriko
- Vector Control Division, Ministry of Health, Kampala, P.O. Box 1661, Uganda
| | - Moses Arinaitwe
- Vector Control Division, Ministry of Health, Kampala, P.O. Box 1661, Uganda
| | - Alison Howell
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Juliet Davies
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Gillian Allison
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - E James LaCourse
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Edridah Muheki
- Vector Control Division, Ministry of Health, Kampala, P.O. Box 1661, Uganda
| | - Narcis B Kabatereine
- Vector Control Division, Ministry of Health, Kampala, P.O. Box 1661, Uganda.,Schistosomiasis Control Initiative, Imperial College London, London, W2 1PG, UK
| | - J Russell Stothard
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
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Al-Shehri H, Stanton MC, LaCourse JE, Atuhaire A, Arinaitwe M, Wamboko A, Adriko M, Kabatereine NB, Stothard JR. An extensive burden of giardiasis associated with intestinal schistosomiasis and anaemia in school children on the shoreline of Lake Albert, Uganda. Trans R Soc Trop Med Hyg 2016; 110:597-603. [PMID: 27864517 DOI: 10.1093/trstmh/trw072] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Revised: 10/24/2016] [Accepted: 11/14/2016] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Water-borne parasitic diseases associated with poverty still blight the lives of African school children. In Uganda, intestinal schistosomiasis is still common along the shoreline of Lake Albert, despite ongoing control, and co-infection with giardiasis and malaria is poorly described. To shed light on putative interactions between diseases, a prospective cross-sectional parasitological survey was undertaken in five primary schools. METHODS Stool samples from 254 school children, aged 5-10 years, were examined by microscopy and rapid diagnostic tests (RDTs), with additional real-time PCR assays for detection of Giardia DNA. A finger-prick blood sample was also taken from each child and tested for malaria, and haemoblobin levels measured. Assocations between diseases and anaemia were assessed. RESULTS Intestinal schistosomiasis (46.5%), giardiasis (41.6%) and malaria (56.2%) were common, and a quarter of children were anaemic (<115 g/L). Up to 87.0% of children were excreting Giardia DNA and the prevalence of heavy infection by real-time PCR (Ct≤19) was 19.5%, being positively associated with light, moderate and heavy egg-patent schistosomiasis, as well as with anaemia. CONCLUSIONS In this setting, an extensive burden of giardiasis was revealed with heavy intensity infections associated with egg-patent intestinal schistosomiasis and anaemia. To improve child health, greater attention on giardiasis is needed along with exploring joined-up actions across diseases that promote better water hygiene and sanitation measures.
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Affiliation(s)
- Hajri Al-Shehri
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK.,Ministry of Health, Asir District, Kingdom of Saudi Arabia
| | | | | | - Aaron Atuhaire
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | - Moses Arinaitwe
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | - Aida Wamboko
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | - Moses Adriko
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | - Narcis B Kabatereine
- Vector Control Division, Ministry of Health, Kampala, Uganda.,Schistosomiasis Control Initiative, School of Public Health, Imperial College London, London W2 1PG, UK
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Deol A, Webster JP, Walker M, Basáñez MG, Hollingsworth TD, Fleming FM, Montresor A, French MD. Development and evaluation of a Markov model to predict changes in schistosomiasis prevalence in response to praziquantel treatment: a case study of Schistosoma mansoni in Uganda and Mali. Parasit Vectors 2016; 9:543. [PMID: 27729063 PMCID: PMC5059905 DOI: 10.1186/s13071-016-1824-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 10/01/2016] [Indexed: 11/23/2022] Open
Abstract
Background Understanding whether schistosomiasis control programmes are on course to control morbidity and potentially switch towards elimination interventions would benefit from user-friendly quantitative tools that facilitate analysis of progress and highlight areas not responding to treatment. This study aimed to develop and evaluate such a tool using large datasets collected during Schistosomiasis Control Initiative-supported control programmes. Methods A discrete-time Markov model was developed using transition probability matrices parameterized with control programme longitudinal data on Schistosoma mansoni obtained from Uganda and Mali. Four matrix variants (A-D) were used to compare different data types for parameterization: A-C from Uganda and D from Mali. Matrix A used data at baseline and year 1 of the control programme; B used year 1 and year 2; C used baseline and year 1 from selected districts, and D used baseline and year 1 Mali data. Model predictions were tested against 3 subsets of the Uganda dataset: dataset 1, the full 4-year longitudinal cohort; dataset 2, from districts not used to parameterize matrix C; dataset 3, cross-sectional data, and dataset 4, from Mali as an independent dataset. Results The model parameterized using matrices A, B and D predicted similar infection dynamics (overall and when stratified by infection intensity). Matrices A-D successfully predicted prevalence in each follow-up year for low and high intensity categories in dataset 1 followed by dataset 2. Matrices A, B and D yielded similar and close matches to dataset 1 with marginal discrepancies when comparing model outputs against datasets 2 and 3. Matrix C produced more variable results, correctly estimating fewer data points. Conclusion Model outputs closely matched observed values and were a useful predictor of the infection dynamics of S. mansoni when using longitudinal and cross-sectional data from Uganda. This also held when the model was tested with data from Mali. This was most apparent when modelling overall infection and in low and high infection intensity areas. Our results indicate the applicability of this Markov model approach as countries aim at reaching their control targets and potentially move towards the elimination of schistosomiasis. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1824-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Arminder Deol
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus) Imperial College London, London, W2 1PG, UK.
| | - Joanne P Webster
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus) Imperial College London, London, W2 1PG, UK.,Department of Pathology and Pathogen Biology, Centre for Emerging, Endemic and Exotic Diseases, Royal Veterinary College, University of London, Herts, London, AL9 7TA, UK.,London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus), Imperial College London, London, W2 1PG, UK
| | - Martin Walker
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus), Imperial College London, London, W2 1PG, UK
| | - Maria-Gloria Basáñez
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus), Imperial College London, London, W2 1PG, UK
| | | | - Fiona M Fleming
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus) Imperial College London, London, W2 1PG, UK
| | - Antonio Montresor
- Neglected Tropical Disease Department, World Health Organization, Avenue Appia, 20, Geneva, Switzerland
| | - Michael D French
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus) Imperial College London, London, W2 1PG, UK
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Ortu G, Assoum M, Wittmann U, Knowles S, Clements M, Ndayishimiye O, Basáñez MG, Lau C, Clements A, Fenwick A, Magalhaes RJS. The impact of an 8-year mass drug administration programme on prevalence, intensity and co-infections of soil-transmitted helminthiases in Burundi. Parasit Vectors 2016; 9:513. [PMID: 27660114 PMCID: PMC5034474 DOI: 10.1186/s13071-016-1794-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 09/07/2016] [Indexed: 11/18/2022] Open
Abstract
Background Soil-transmitted helminth (STH) infections are amongst the most prevalent infections in the world. Mass drug administration (MDA) programmes have become the most commonly used national interventions for endemic countries to achieve elimination. This paper aims to describe the effect of an 8-year MDA programme on the prevalence, intensity of infection and co-infection of STH in Burundi from 2007 to 2014 and critically appraise the trajectory towards STH elimination in the country. Results Annual STH parasitological surveys (specifically, a “pilot study” from 2007 to 2011, an “extension study” from 2008 to 2011, and a “national reassessment” in 2014; n = 27,658 children), showed a significant drop in prevalence of infection with any STH (“pooled STH”) between baseline and 2011 in both studies, falling from 32 to 16 % in the pilot study, and from 35 to 16 % in the extension study. Most STH infections were of low intensity according to WHO classification. The national reassessment in 2014 showed that prevalence of pooled STH remained significantly below the prevalence in 2007 in both studies but there was no further decrease in STH prevalence from 2011 levels during this time. Spatial dependence analysis showed that prevalence of Trichuris trichiura and Ascaris lumbricoides had a tendency to cluster over the years, whilst only trends in spatial dependence were evident for hookworm infections. Spatial dependence fluctuated over the course of the programme for Ascaris lumbricoides and Trichuris trichiura. However, spatial trends in spatial dependence were evident in 2010 for Ascaris lumbricoides. Analysis of spatial clustering of intensity of infection and heavy infections revealed that the intensity changed over time for all parasites. Heavy intensity was only evident in Ascaris lumbricoides for 2008 and did not appear in proceeding years and other parasites. Conclusions These results demonstrate that sustained annual MDA significantly reduced the prevalence of STH infection in school-age children but was unable to achieve elimination. Additionally, significant decline in prevalence was accompanied by a drop in spatial clustering of infection indicators across all sites from 2008. The lack of consistency in the results of the spatial dependence analysis highlights that MDA programmes can interrupt the normal transmission dynamics of STH parasites. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1794-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Giuseppina Ortu
- Schistosomiasis Control Initiative, Imperial College London, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St. Mary's Campus), Norfolk Place, London, W2 1PG, UK.
| | - Mohamad Assoum
- School of Medicine, The University of Queensland, Brisbane, Australia.,Children's Health and Environment Program, Child Health Research Centre, The University of Queensland, Brisbane, Australia
| | - Udo Wittmann
- Schistosomiasis Control Initiative, Imperial College London, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St. Mary's Campus), Norfolk Place, London, W2 1PG, UK
| | - Sarah Knowles
- Schistosomiasis Control Initiative, Imperial College London, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St. Mary's Campus), Norfolk Place, London, W2 1PG, UK
| | - Michelle Clements
- Schistosomiasis Control Initiative, Imperial College London, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St. Mary's Campus), Norfolk Place, London, W2 1PG, UK
| | - Onésime Ndayishimiye
- Programme National Intégré de lutte contre les Maladies Tropicales Négligées et la Cécité (PNIMTNC) - Ministère de la Santé Publique et de la lutte contre le SIDA, Bujumbura, Burundi
| | - Maria-Gloria Basáñez
- Schistosomiasis Control Initiative, Imperial College London, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St. Mary's Campus), Norfolk Place, London, W2 1PG, UK.,London Centre for Neglected Tropical Disease Research, Imperial College London, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St. Mary's Campus), Norfolk Place, London, W2 1PG, UK
| | - Colleen Lau
- Children's Health and Environment Program, Child Health Research Centre, The University of Queensland, Brisbane, Australia.,Research School of Population Health, Australian National University, Canberra, Australia
| | - Archie Clements
- Research School of Population Health, Australian National University, Canberra, Australia
| | - Alan Fenwick
- Schistosomiasis Control Initiative, Imperial College London, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St. Mary's Campus), Norfolk Place, London, W2 1PG, UK
| | - Ricardo J Soares Magalhaes
- Children's Health and Environment Program, Child Health Research Centre, The University of Queensland, Brisbane, Australia.,School of Veterinary Science, The University of Queensland (Gatton Campus), Via Warrego Highway, Gatton, QLD, 4343, Australia
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Crellen T, Walker M, Lamberton PHL, Kabatereine NB, Tukahebwa EM, Cotton JA, Webster JP. Reduced Efficacy of Praziquantel Against Schistosoma mansoni Is Associated With Multiple Rounds of Mass Drug Administration. Clin Infect Dis 2016; 63:1151-1159. [PMID: 27470241 PMCID: PMC5064161 DOI: 10.1093/cid/ciw506] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Accepted: 07/17/2016] [Indexed: 01/03/2023] Open
Abstract
Background. Mass drug administration (MDA) with praziquantel is the cornerstone of schistosomiasis control in sub-Saharan Africa. The effectiveness of this strategy is dependent on the continued high efficacy of praziquantel; however, drug efficacy is rarely monitored using appropriate statistical approaches that can detect early signs of wane. Methods. We conducted a repeated cross-sectional study, examining children infected with Schistosoma mansoni from 6 schools in Uganda that had previously received between 1 and 9 rounds of MDA with praziquantel. We collected up to 12 S. mansoni egg counts from 414 children aged 6–12 years before and 25–27 days after treatment with praziquantel. We estimated individual patient egg reduction rates (ERRs) using a statistical model to explore the influence of covariates, including the number of prior MDA rounds. Results. The average ERR among children within schools that had received 8 or 9 previous rounds of MDA (95% Bayesian credible interval [BCI], 88.23%–93.64%) was statistically significantly lower than the average in schools that had received 5 rounds (95% BCI, 96.13%–99.08%) or 1 round (95% BCI, 95.51%–98.96%) of MDA. We estimate that 5.11%, 4.55%, and 16.42% of children from schools that had received 1, 5, and 8–9 rounds of MDA, respectively, had ERRs below the 90% threshold of optimal praziquantel efficacy set by the World Health Organization. Conclusions. The reduced efficacy of praziquantel in schools with a higher exposure to MDA may pose a threat to the effectiveness of schistosomiasis control programs. We call for the efficacy of anthelmintic drugs used in MDA to be closely monitored.
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Affiliation(s)
- Thomas Crellen
- Department of Infectious Disease Epidemiology and the London Centre for Neglected Tropical Disease Research, Imperial College London, St Mary's Campus Wellcome Trust Sanger Institute, Hinxton Department of Pathology and Pathogen Biology, Royal Veterinary College, University of London, Hertfordshire
| | - Martin Walker
- Department of Infectious Disease Epidemiology and the London Centre for Neglected Tropical Disease Research, Imperial College London, St Mary's Campus
| | - Poppy H L Lamberton
- Department of Infectious Disease Epidemiology and the London Centre for Neglected Tropical Disease Research, Imperial College London, St Mary's Campus Institute of Biodiversity, Animal Health & Comparative Medicine and Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, United Kingdom
| | | | | | | | - Joanne P Webster
- Department of Infectious Disease Epidemiology and the London Centre for Neglected Tropical Disease Research, Imperial College London, St Mary's Campus Department of Pathology and Pathogen Biology, Royal Veterinary College, University of London, Hertfordshire
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A centenary of Robert T. Leiper's lasting legacy on schistosomiasis and a COUNTDOWN on control of neglected tropical diseases. Parasitology 2016; 144:1602-1612. [PMID: 27363810 PMCID: PMC5964474 DOI: 10.1017/s0031182016000998] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Part of Robert T. Leiper's (1881–1969) lasting legacy in medical helminthology is grounded on his pioneering work on schistosomiasis (Bilharzia). Having undertaken many expeditions to the tropics, his fascination with parasite life cycles typically allowed him to devise simple preventive measures that curtailed transmission. Building on his formative work with others in Africa and Asia, and again in Egypt in 1915, he elucidated the life cycles of African schistosomes. His mandate, then commissioned by the British War Office, was to prevent and break transmission of this disease in British troops. This he did by raising standing orders based on simple water hygiene measures. Whilst feasible in military camp settings, today their routine implementation is sadly out of reach for millions of Africans living in poverty. Whilst we celebrate the centenary of Leiper's research we draw attention to some of his lesser known colleagues, then focus on schistosomiasis in Uganda discussing why expanded access to treatment with praziquantel is needed now. Looking to WHO 2020 targets for neglected tropical diseases, we introduce COUNTDOWN, an implementation research consortium funded by DFID, UK, which fosters the scale-up of interventions and confirm the current relevance of Leiper's original research.
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Onkanga IO, Mwinzi PNM, Muchiri G, Andiego K, Omedo M, Karanja DMS, Wiegand RE, Secor WE, Montgomery SP. Impact of two rounds of praziquantel mass drug administration on Schistosoma mansoni infection prevalence and intensity: a comparison between community wide treatment and school based treatment in western Kenya. Int J Parasitol 2016; 46:439-45. [PMID: 26940547 PMCID: PMC4920687 DOI: 10.1016/j.ijpara.2016.01.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/21/2016] [Accepted: 01/22/2016] [Indexed: 11/16/2022]
Abstract
This study compared the effectiveness of the community-wide treatment and school-based treatment approaches in the control of Schistosoma mansoni infections in villages with ⩾25% prevalence in western Kenya. Stool samples from first year students, 9-12year olds and adults (20-55years) were analyzed by the Kato-Katz technique for S. mansoni eggs. After two rounds of treatment, S. mansoni prevalence and intensity levels significantly declined in both treatment approaches. Prevalence comparisons between the two approaches did not show any significant differences following treatment. However, infection intensity levels in the 9-12year old school-attending pupils were significantly higher in the community-wide treatment arm than in the school-based treatment arm. Nevertheless, significant reductions in S. mansoni infection prevalence and intensity levels were achieved among school-age children regardless of the treatment approach used.
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Affiliation(s)
- Isaac O Onkanga
- Center for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Pauline N M Mwinzi
- Center for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Geoffrey Muchiri
- Center for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Kennedy Andiego
- Center for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Martin Omedo
- Center for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Diana M S Karanja
- Center for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Ryan E Wiegand
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Rd, N.E., Atlanta, GA 30329, USA
| | - W Evan Secor
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Rd, N.E., Atlanta, GA 30329, USA.
| | - Susan P Montgomery
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Rd, N.E., Atlanta, GA 30329, USA
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Bartsch SM, Hotez PJ, Hertenstein DL, Diemert DJ, Zapf KM, Bottazzi ME, Bethony JM, Brown ST, Lee BY. Modeling the economic and epidemiologic impact of hookworm vaccine and mass drug administration (MDA) in Brazil, a high transmission setting. Vaccine 2016; 34:2197-206. [PMID: 27002501 DOI: 10.1016/j.vaccine.2016.03.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 03/03/2016] [Accepted: 03/09/2016] [Indexed: 10/22/2022]
Abstract
BACKGROUND Although mass drug administration (MDA) has helped reduce morbidity attributed to soil-transmitted helminth infections in children, its limitations for hookworm infection have motivated the development of a human hookworm vaccine to both improve morbidity control and ultimately help block hookworm transmission leading to elimination. However, the potential economic and epidemiologic impact of a preventive vaccine has not been fully evaluated. METHODS We developed a dynamic compartment model coupled to a clinical and economics outcomes model representing both the human and hookworm populations in a high transmission region of Brazil. Experiments simulated different implementation scenarios of MDA and vaccination under varying circumstances. RESULTS Considering only intervention costs, both annual MDA and vaccination were highly cost-effective (ICERs ≤ $790/DALY averted) compared to no intervention, with vaccination resulting in lower incremental cost-effectiveness ratios (ICERs ≤ $444/DALY averted). From the societal perspective, vaccination was economically dominant (i.e., less costly and more effective) versus annual MDA in all tested scenarios, except when vaccination was less efficacious (20% efficacy, 5 year duration) and MDA coverage was 75%. Increasing the vaccine's duration of protection and efficacy, and including a booster injection in adulthood all increased the benefits of vaccination (i.e., resulted in lower hookworm prevalence, averted more disability-adjusted life years, and saved more costs). Assuming its target product profile, a pediatric hookworm vaccine drastically decreased hookworm prevalence in children to 14.6% after 20 years, compared to 57.2% with no intervention and 54.1% with MDA. The addition of a booster in adulthood further reduced the overall prevalence from 68.0% to 36.0% and nearly eliminated hookworm infection in children. CONCLUSION Using a human hookworm vaccine would be cost-effective and in many cases economically dominant, providing both health benefits and cost-savings. It could become a key technology in effecting control and elimination efforts for hookworm globally.
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Affiliation(s)
- Sarah M Bartsch
- Public Health Computational and Operational Research (PHICOR), Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA; Global Obesity Prevention Center, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA
| | - Peter J Hotez
- National School of Tropical Medicine, and Departments of Pediatrics and Molecular Virology & Microbiology, Baylor College of Medicine, One Baylor Plaza, BCM113, Houston, TX 77030, USA; Sabin Vaccine Institute, 2000 Pennsylvania Avenue NW, Washington, DC 20006, USA
| | - Daniel L Hertenstein
- Public Health Computational and Operational Research (PHICOR), Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA; Global Obesity Prevention Center, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA
| | - David J Diemert
- Sabin Vaccine Institute, 2000 Pennsylvania Avenue NW, Washington, DC 20006, USA; Department of Microbiology, Immunology and Tropical Medicine, The George Washington University Medical Center, Washington, DC 20037, USA
| | - Kristina M Zapf
- Public Health Computational and Operational Research (PHICOR), Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA; Global Obesity Prevention Center, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA
| | - Maria Elena Bottazzi
- National School of Tropical Medicine, and Departments of Pediatrics and Molecular Virology & Microbiology, Baylor College of Medicine, One Baylor Plaza, BCM113, Houston, TX 77030, USA; Sabin Vaccine Institute, 2000 Pennsylvania Avenue NW, Washington, DC 20006, USA
| | - Jeffrey M Bethony
- Sabin Vaccine Institute, 2000 Pennsylvania Avenue NW, Washington, DC 20006, USA; Department of Microbiology, Immunology and Tropical Medicine, The George Washington University Medical Center, Washington, DC 20037, USA
| | - Shawn T Brown
- Pittsburgh Supercomputing Center, Carnegie Mellon University, 300S Craig St, Pittsburgh, PA 15213, USA
| | - Bruce Y Lee
- Public Health Computational and Operational Research (PHICOR), Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA; Global Obesity Prevention Center, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA.
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47
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Kateera F, Ingabire CM, Hakizimana E, Kalinda P, Mens PF, Grobusch MP, Mutesa L, van Vugt M. Malaria, anaemia and under-nutrition: three frequently co-existing conditions among preschool children in rural Rwanda. Malar J 2015; 14:440. [PMID: 26542672 PMCID: PMC4635556 DOI: 10.1186/s12936-015-0973-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 10/28/2015] [Indexed: 11/23/2022] Open
Abstract
Background Malaria, anaemia and under-nutrition are three highly prevalent and frequently co-existing diseases that cause significant morbidity and mortality particularly among children aged less than 5 years. Currently, there is paucity of conclusive studies on the burden of and associations between malaria, anaemia and under-nutrition in Rwanda and comparable sub-Saharan and thus, this study measured the prevalence of malaria parasitaemia, anaemia and under-nutrition among preschool age children in a rural Rwandan setting and evaluated for interactions between and risk determinants for these three conditions. Methods A cross-sectional household (HH) survey involving children aged 6–59 months was conducted. Data on malaria parasitaemia, haemoglobin densities, anthropometry, demographics, socioeconomic status (SES) and malaria prevention knowledge and practices were collected. Results The prevalences of malaria parasitaemia and anaemia were 5.9 and 7.0 %, respectively, whilst the prevalence of stunting was 41.3 %. Malaria parasitaemia risk differed by age groups with odds ratio (OR) = 2.53; P = 0.04 for age group 24–35 months, OR = 3.5; P = 0.037 for age group 36–47 months, and OR = 3.03; P = 0.014 for age group 48–60 months, whilst a reduced risk was found among children living in high SES HHs (OR = 0.37; P = 0.029). Risk of anaemia was high among children aged ≥12 months, those with malaria parasitaemia (OR = 3.86; P ≤ 0.0001) and children living in HHs of lower SES. Overall, under-nutrition was not associated with malaria parasitaemia. Underweight was higher among males (OR = 1.444; P = 0.019) and children with anaemia (OR = 1.98; P = 0.004). Conclusions In this study group, four in 10 and one in 10 children were found stunted and underweight, respectively, in an area of low malaria transmission. Under-nutrition was not associated with malaria risk. While the high prevalence of stunting requires urgent response, reductions in malaria parasitaemia and anaemia rates may require, in addition to scaled-up use of insecticide-treated bed nets and indoor residual insecticide spraying, improvements in HH SES and better housing to reduce risk of malaria.
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Affiliation(s)
- Fredrick Kateera
- Division of Internal Medicine, Department of Infectious Diseases, Centre of Tropical Medicine and Travel Medicine, Academic Medical Centre, Meibergdreef 9, 1100 DE, Amsterdam, The Netherlands. .,Medical Research Centre Division, Rwanda Biomedical Centre, PO Box 7162, Kigali, Rwanda.
| | - Chantal M Ingabire
- Medical Research Centre Division, Rwanda Biomedical Centre, PO Box 7162, Kigali, Rwanda.
| | - Emmanuel Hakizimana
- Malaria and Other Parasitic Diseases Division, Rwanda Biomedical Centre, Kigali, Rwanda.
| | - Parfait Kalinda
- Medical Research Centre Division, Rwanda Biomedical Centre, PO Box 7162, Kigali, Rwanda.
| | - Petra F Mens
- Division of Internal Medicine, Department of Infectious Diseases, Centre of Tropical Medicine and Travel Medicine, Academic Medical Centre, Meibergdreef 9, 1100 DE, Amsterdam, The Netherlands. .,Royal Tropical Institute, Koninklijk Instituut voor de Tropen, KIT Biomedical Research, Meibergdreef 39, 1105 AZ, Amsterdam, The Netherlands.
| | - Martin P Grobusch
- Division of Internal Medicine, Department of Infectious Diseases, Centre of Tropical Medicine and Travel Medicine, Academic Medical Centre, Meibergdreef 9, 1100 DE, Amsterdam, The Netherlands.
| | - Leon Mutesa
- College of Medicine and Health Sciences, University of Rwanda, Kigali, Rwanda.
| | - Michèle van Vugt
- Division of Internal Medicine, Department of Infectious Diseases, Centre of Tropical Medicine and Travel Medicine, Academic Medical Centre, Meibergdreef 9, 1100 DE, Amsterdam, The Netherlands.
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Influence of Schistosoma mansoni and Hookworm Infection Intensities on Anaemia in Ugandan Villages. PLoS Negl Trop Dis 2015; 9:e0004193. [PMID: 26513151 PMCID: PMC4626098 DOI: 10.1371/journal.pntd.0004193] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Accepted: 10/05/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The association of anaemia with intestinal schistosomiasis and hookworm infections are poorly explored in populations that are not limited to children or pregnant women. METHODS We sampled 1,832 individuals aged 5-90 years from 30 communities in Mayuge District, Uganda. Demographic, village, and parasitological data were collected. Infection risk factors were compared in ordinal logistic regressions. Anaemia and infection intensities were analyzed in multilevel models, and population attributable fractions were estimated. FINDINGS Household and village-level predictors of Schistosoma mansoni and hookworm were opposite in direction or significant for single infections. S. mansoni was found primarily in children, whereas hookworm was prevalent amongst the elderly. Anaemia was more prevalent in individuals with S. mansoni and increased by 2.86 fold (p-value<0.001) with heavy S. mansoni infection intensity. Individuals with heavy hookworm were 1.65 times (p-value = 0.008) more likely to have anaemia than uninfected participants. Amongst individuals with heavy S. mansoni infection intensity, 32.0% (p-value<0.001) of anaemia could be attributed to S. mansoni. For people with heavy hookworm infections, 23.7% (p-value = 0.002) of anaemia could be attributed to hookworm. A greater fraction of anaemia (24.9%, p-value = 0.002) was attributable to heavy hookworm infections in adults (excluding pregnant women) as opposed to heavy hookworm infections in school-aged children and pregnant women (20.2%, p-value = 0.001). CONCLUSION Community-based surveys captured anaemia in children and adults affected by S. mansoni and hookworm infections. For areas endemic with schistosomiasis or hookworm infections, WHO guidelines should include adults for treatment in helminth control programmes.
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Siza JE, Kaatano GM, Chai JY, Eom KS, Rim HJ, Yong TS, Min DY, Chang SY, Ko Y, Changalucha JM. Prevalence of Schistosomes and Soil-Transmitted Helminths among Schoolchildren in Lake Victoria Basin, Tanzania. THE KOREAN JOURNAL OF PARASITOLOGY 2015; 53:515-24. [PMID: 26537030 PMCID: PMC4635830 DOI: 10.3347/kjp.2015.53.5.515] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 09/30/2015] [Accepted: 10/04/2015] [Indexed: 12/02/2022]
Abstract
The objectives of this study was to conduct a survey on schistosomiasis and soil-transmitted helminth (STH) infections in order to come up with feasible control strategies in Lake Victoria basin, Tanzania. Depending on the size of the school, 150-200 schoolchildren were recruited for the study. Duplicate Kato-Katz stool smears were prepared from each child and microscopically examined for Schistosoma mansoni and STHs. Urine specimens were examined for Schistosoma haematobium eggs using the filtration technique. After the survey, mass drug administration was done using praziquantel and albendazole for schistosomiasis and STHs infections, respectively. A total of 5,952 schoolchildren from 36 schools were recruited for the study and had their stool and urine specimens examined. Out of 5,952 schoolchildren, 898 (15.1%) were positive for S. mansoni, 754 (12.6%) for hookworms, 188 (3.2%) for Ascaris lumblicoides, and 5 (0.008%) for Trichuris trichiura. Out of 5,826 schoolchildren who provided urine samples, 519 (8.9%) were positive for S. haematobium eggs. The results revealed that intestinal schistosomiasis, urogenital schistosomiasis, and STH infections are highly prevalent throughought the lake basin. The high prevalence of intestinal and urogenital schistosomisiasis in the study area was a function of the distance from Lake Victoria, the former being more prevalent at localities close to the lake, whilst the latter is more so away from it. Control of schistosomiasis and STHs in the study area requires an integrated strategy that involves provision of health education to communities, regular treatments, and provision of adequate safe water supply and sanitation facilities.
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Affiliation(s)
- Julius E Siza
- National Institute of Medical Research, P.O. Box 1462, Mwanza, Tanzania
| | - Godfrey M Kaatano
- National Institute of Medical Research, P.O. Box 1462, Mwanza, Tanzania
| | - Jong-Yil Chai
- Department of Parasitology and Tropical Medicine, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Keeseon S Eom
- Department of Parasitology and Medical Research Institute, Chungbuk National University School of Medicine, Cheongju 28644, Korea
| | - Han-Jong Rim
- Department of Parasitology, College of Medicine, Korea University, Seoul 02841, Korea
| | - Tai-Soon Yong
- Department of Environmental Medical Biology and Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Duk-Young Min
- Department of Microbiology and Immunology, Eulji University College of Medicine, Daejeon 35233, Korea
| | - Su Young Chang
- Good Neighbors International, Tanzania Western Chapter, P.O. Box 367, Mwanza, Tanzania
| | - Yunsuk Ko
- Good Neighbors International, Tanzania Western Chapter, P.O. Box 367, Mwanza, Tanzania
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50
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French MD, Churcher TS, Webster JP, Fleming FM, Fenwick A, Kabatereine NB, Sacko M, Garba A, Toure S, Nyandindi U, Mwansa J, Blair L, Bosqué-Oliva E, Basáñez MG. Estimation of changes in the force of infection for intestinal and urogenital schistosomiasis in countries with schistosomiasis control initiative-assisted programmes. Parasit Vectors 2015; 8:558. [PMID: 26499981 PMCID: PMC4619997 DOI: 10.1186/s13071-015-1138-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 10/03/2015] [Indexed: 11/07/2022] Open
Abstract
Background The last decade has seen an expansion of national schistosomiasis control programmes in Africa based on large-scale preventative chemotherapy. In many areas this has resulted in considerable reductions in infection and morbidity levels in treated individuals. In this paper, we quantify changes in the force of infection (FOI), defined here as the per (human) host parasite establishment rate, to ascertain the impact on transmission of some of these programmes under the umbrella of the Schistosomiasis Control Initiative (SCI). Methods A previous model for the transmission dynamics of Schistosoma mansoni was adapted here to S. haematobium. These models were fitted to longitudinal cohort (infection intensity) monitoring and evaluation data. Changes in the FOI following up to three annual rounds of praziquantel were estimated for Burkina Faso, Mali, Niger, Tanzania, Uganda, and Zambia in sub-Saharan Africa (SSA) according to country, baseline endemicity and schistosome species. Since schistosomiasis transmission is known to be highly focal, changes in the FOI at a finer geographical scale (that of sentinel site) were also estimated for S. mansoni in Uganda. Results Substantial and statistically significant reductions in the FOI relative to baseline were recorded in the majority of, but not all, combinations of country, parasite species, and endemicity areas. At the finer geographical scale assessed within Uganda, marked heterogeneity in the magnitude and direction of the relative changes in FOI was observed that would not have been appreciated by a coarser-scale analysis. Conclusions Reductions in the rate at which humans acquire schistosomes have been achieved in many areas of SSA countries assisted by the SCI, while challenges in effectively reducing transmission persist in others. Understanding the underlying heterogeneity in the impact and performance of the control intervention at the level of the transmission site will become increasingly important for programmes transitioning from morbidity reduction to elimination of infection. Such analyses will require a fine-scale approach. The lack of association found between programmatic variables, such as therapeutic treatment coverage (recorded at district level) and changes in FOI (at sentinel site level) is discussed and recommendations are made.
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Affiliation(s)
- Michael D French
- Schistosomiasis Control Initiative, Faculty of Medicine, Imperial College London, St. Mary's Hospital, Norfolk Place, London, W2 1PG, UK.
| | - Thomas S Churcher
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, Norfolk Place, London, W2 1PG, UK.
| | - Joanne P Webster
- Schistosomiasis Control Initiative, Faculty of Medicine, Imperial College London, St. Mary's Hospital, Norfolk Place, London, W2 1PG, UK. .,Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, Norfolk Place, London, W2 1PG, UK. .,Present address: Department of Pathology and Pathogen Biology, Centre for Emerging, Endemic and Exotic Diseases (CEEED), Royal Veterinary College, University of London, Hawkshead Campus, Herts, AL97TA, London, UK.
| | - Fiona M Fleming
- Schistosomiasis Control Initiative, Faculty of Medicine, Imperial College London, St. Mary's Hospital, Norfolk Place, London, W2 1PG, UK.
| | - Alan Fenwick
- Schistosomiasis Control Initiative, Faculty of Medicine, Imperial College London, St. Mary's Hospital, Norfolk Place, London, W2 1PG, UK.
| | | | | | - Amadou Garba
- Ministère de la Santé Publique (now WHO), Niamey, Niger. .,Present address: World Health Organization, 20, avenue Appia, 1211, Geneva 27, Switzerland.
| | | | | | - James Mwansa
- Department of Pathology and Microbiology, University of Zambia School of Medicine, University Teaching Hospital, Lusaka, Zambia.
| | - Lynsey Blair
- Schistosomiasis Control Initiative, Faculty of Medicine, Imperial College London, St. Mary's Hospital, Norfolk Place, London, W2 1PG, UK.
| | - Elisa Bosqué-Oliva
- Schistosomiasis Control Initiative, Faculty of Medicine, Imperial College London, St. Mary's Hospital, Norfolk Place, London, W2 1PG, UK. .,Present address: The END FUND, New York, NY, USA.
| | - Maria-Gloria Basáñez
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, Norfolk Place, London, W2 1PG, UK.
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