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Mutapi F, Garba A, Woolhouse M, Kazyoba P. Paediatric schistosomiasis: last mile preparations for deploying paediatric praziquantel. Trends Parasitol 2024; 40:687-695. [PMID: 39033047 DOI: 10.1016/j.pt.2024.06.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Revised: 06/12/2024] [Accepted: 06/19/2024] [Indexed: 07/23/2024]
Abstract
Schistosomiasis is the second most important parasitic disease of public health importance in Africa, affecting over 50 million children aged <5 years old. Schistosomiasis control has focused on treating school-aged children (>6 years) and adults through mass drug administration (MDA). Following the recent development of a paediatric praziquantel (PZQ) formulation for children aged <5 years, there are now concerted efforts to determine optimal and effective ways to integrate treatment of these children into national schistosomiasis control programmes. In this opinion article we outline the pathway for successful drug access, delivery, and mainstreaming of the new formulation in endemic country health systems. Effective and sustained paediatric schistosomiasis treatment is an important target of the 2030 World Health Organization (WHO) neglected tropical diseases (NTDs) roadmap.
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Affiliation(s)
- Francisca Mutapi
- Institute of Immunology and Infection Research, University of Edinburgh, Ashworth Laboratories, King's Buildings, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK; Tackling Infections to Benefit Africa (TIBA) Partnership, TIBA Global Health Research Unit, University of Edinburgh, Ashworth Laboratories, King's Buildings, Charlotte Auerbach Road, Edinburgh, EH9 3FL, UK.
| | - Amadou Garba
- Department of the Control of Neglected Tropical Diseases, World Health Organization, Geneva, 1211, Switzerland
| | - Mark Woolhouse
- Tackling Infections to Benefit Africa (TIBA) Partnership, TIBA Global Health Research Unit, University of Edinburgh, Ashworth Laboratories, King's Buildings, Charlotte Auerbach Road, Edinburgh, EH9 3FL, UK; Usher Institute of Population Health Sciences and Informatics, Ashworth Laboratories, University of Edinburgh, Edinburgh, UK
| | - Paul Kazyoba
- National Institute for Medical Research, 2448 Barack Obama Dr, Dar es Salaam, Tanzania; TIBA Partnership, NIMR, Tanzania, 2448 Barack Obama Dr, Dar es Salaam, Tanzania
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Rujeni N, Bayingana JB, Nyandwi E, Ntakarutimana A, Kagabo J, Rutayisire R, Shema E, Kanimba P, Mbonigaba JB, Ruberanziza E. Prevalence Mapping of Schistosoma mansoni Among Pre-school Age Children in Rwanda. Front Pediatr 2022; 10:906177. [PMID: 35813371 PMCID: PMC9267951 DOI: 10.3389/fped.2022.906177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 05/20/2022] [Indexed: 11/25/2022] Open
Abstract
Schistosoma mansoni is endemic in Rwanda, and control programs have been implemented with a special focus on school-age children (SAC), ignoring pre-school age children (pre-SAC) for which the actual prevalence of the disease is not well established. This study consisted of a cross-sectional quantitative mapping of the distribution of Schistosoma mansoni and identification of associated risk factors among pre-SAC throughout the country. The study covered all the 17 districts of Rwanda endemic for Schistosoma mansoni, with a total sample of 4,675 children enrolled from 80 purposively selected villages. The parasitological assessment of children's urine and stool samples was conducted using CCA and Kato Katz methods, respectively, for infection detection. A standard questionnaire was used to collect data on the risk factors, and geospatial assessment was performed using tablets and GPS to record geographic coordinates for plotting locations on maps using ArcGIS software. The overall prevalence of S. mansoni infection across the surveyed areas was 24 and 0.8% by CCA and Kato-Katz, respectively. Infection was significantly associated with bathing children in open water bodies. Furthermore, pre-SAC looked after by siblings (sisters) were two times as much likely to be infected compared to those looked after by mothers. Schistosomiasis control interventions are needed for pre-SAC to limit their exposure to open water bodies with expectations of adapted chemotherapy to be availed. Community-based deworming campaigns may be the best way to ensure good treatment coverage of pre-SAC in Rwanda.
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Affiliation(s)
- Nadine Rujeni
- School of Health Sciences, College of Medicine and Health Sciences, University of Rwanda, Kigali, Rwanda
| | - Jean Bosco Bayingana
- School of Health Sciences, College of Medicine and Health Sciences, University of Rwanda, Kigali, Rwanda
- Single Project Implementation Unit, University of Rwanda, Kigali, Rwanda
| | - Elias Nyandwi
- Centre for Geographic Information Systems and Remote Sensing, College of Science and Technology, University of Rwanda, Kigali, Rwanda
| | - Amans Ntakarutimana
- School of Health Sciences, College of Medicine and Health Sciences, University of Rwanda, Kigali, Rwanda
| | - Joseph Kagabo
- School of Health Sciences, College of Medicine and Health Sciences, University of Rwanda, Kigali, Rwanda
| | - Reverien Rutayisire
- School of Health Sciences, College of Medicine and Health Sciences, University of Rwanda, Kigali, Rwanda
| | - Eliah Shema
- School of Health Sciences, College of Medicine and Health Sciences, University of Rwanda, Kigali, Rwanda
| | - Philbert Kanimba
- School of Health Sciences, College of Medicine and Health Sciences, University of Rwanda, Kigali, Rwanda
| | - Jean Bosco Mbonigaba
- Neglected Tropical Diseases and Other Parasitic Diseases Unit, Rwanda Biomedical Center, Ministry of Health, Kigali, Rwanda
| | - Eugene Ruberanziza
- Neglected Tropical Diseases and Other Parasitic Diseases Unit, Rwanda Biomedical Center, Ministry of Health, Kigali, Rwanda
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Mewamba EM, Tiofack AAZ, Kamdem CN, Ngassam RIK, Mbagnia MCT, Nyangiri O, Noyes H, Womeni HM, Njiokou F, Simo G. Field assessment in Cameroon of a reader of POC-CCA lateral flow strips for the quantification of Schistosoma mansoni circulating cathodic antigen in urine. PLoS Negl Trop Dis 2021; 15:e0009569. [PMID: 34260610 PMCID: PMC8312929 DOI: 10.1371/journal.pntd.0009569] [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: 02/14/2021] [Revised: 07/26/2021] [Accepted: 06/16/2021] [Indexed: 11/23/2022] Open
Abstract
Background Determining Schistosoma mansoni infection rate and intensity is challenging due to the low sensitivity of the Kato-Katz (KK) test that underestimates the true disease prevalence. Circulating cathodic antigen (CCA) excreted in urine is constantly produced by adult worms and has been used as the basis of a simple, non-invasive point of care test (POC-CCA) for Schistosoma mansoni infections. Although the abundance of CCA in urine is proportional to worm burden, the POC-CCA test is marketed as a qualitative test, making it difficult to investigate the wide range of infection intensities. This study was designed to compare the prevalence and intensity of S. mansoni by KK and POC-CCA and quantify, on fresh and frozen (<-20°C) urine samples, CCA using the visual scores and the ESEquant LR3 reader. Methodology Stool and urine samples were collected from 759 school-aged children. The prevalence and intensity of S. mansoni were determined using KK and POC-CCA. The degree of the positivity of POC-CCA was estimated by quantifying CCA on fresh and frozen urine samples using visual scores and strip reader. The prevalence, the infection intensity as well the relative amounts of CCA were compared. Results The S. mansoni infection rates inferred from POC-CCA and KK were 40.7% and 9.4% respectively. Good correlations were observed between infection intensities recorded by; i) the reader and visual scoring system on fresh (Rho = 0.89) and frozen samples (Rho = 0.97), ii) the reader on fresh urine samples and KK (epg) (Rho = 0.44). Nevertheless, 238 POC-CCA positive children were negative for KK, and sixteen of them had high levels of CCA. The correlation between results from the reader on fresh and frozen samples was good (Rho = 0.85). On frozen samples, CCA was not detected in 55 samples that were positive in fresh urine samples. Conclusion This study confirmed the low sensitivity of KK and the high capacity of POC-CCA to provide reliable data on the prevalence and intensity of S. mansoni infections. The lateral flow reader enabled accurate quantification of CCA under field conditions on fresh and frozen urine samples with less time and effort than KK. Diagnosis of schistosomiasis has relied on the Kato-Katz technique which remains challenging due to its low sensitivity. To overcome this limitation, the Point-of-care-Circulating Cathodic Antigen (POC-CCA) test has been developed to detect CCA produced by adult living worm. However, this test is sold for qualitative use only because it is difficult to estimate the intensity of the positive band by eye. This study was designed with the aim of comparing the prevalence and intensity of S. mansoni infections by KK and POC-CCA and quantifying under field conditions on fresh and frozen (<-20°C) urine samples, CCA using the visual scores and the ESEquant LR3 reader. We conducted the KK and POC-CCA tests on stool and urine samples collected from SAC (5 to 4 years) in Makenene, Cameroon. Our results showed discrepancies between results from KK and POC-CCA test. The numerical values generated by the reader made it possible to avoid subjective visual interpretation of POC-CCA results. This study also identified children with high levels of CCA in their urine but without schistosome eggs in their stools. The good correlation observed between results obtained on fresh and frozen urine samples confirmed that POC-CCA test can be used on samples stored for one year at -20° C.
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Affiliation(s)
- Estelle Mezajou Mewamba
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Arnol Auvaker Zebaze Tiofack
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Cyrille Nguemnang Kamdem
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | | | - Mureille Carole Tchami Mbagnia
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Oscar Nyangiri
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Harry Noyes
- Centre for Genomic Research, University of Liverpool, Liverpool, United Kingdom
| | - Hilaire Marcaire Womeni
- Unité de Recherche de Biochimie, des plantes Médicinales, des Sciences alimentaires et Nutrition, University of Dschang, Dschang, Cameroon
| | - Flobert Njiokou
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
- Centre for Research in Infectious Diseases, Yaoundé, Cameroon
| | - Gustave Simo
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
- * E-mail: ,
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Sheehy C, Lawson H, Andriamasy EH, Russell HJ, Reid A, Raderalazasoa GU, Dodge G, Kornitschky R, Penney JMS, Ranaivoson TN, Andrianiaina A, Emmanoela JS, Bustinduy AL, Stothard JR, Andrianjaka L, Spencer SA. Prevalence of intestinal schistosomiasis in pre-school aged children: a pilot survey in Marolambo District, Madagascar. Infect Dis Poverty 2021; 10:87. [PMID: 34172089 PMCID: PMC8235251 DOI: 10.1186/s40249-021-00871-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 05/07/2021] [Indexed: 12/28/2022] Open
Abstract
School-aged children (SAC) have a considerable burden of intestinal schistosomiasis in Madagascar yet its burden in pre-school aged children (PSAC) is currently overlooked. To assess the at-risk status of PSAC, we undertook a pilot epidemiological survey in June 2019 examining children (n = 89), aged 2–4-years of balanced gender, in six remote villages in Marolambo District, Madagascar. Diagnosis included use of urine-circulating cathodic antigen (CCA) dipsticks and coproscopy of stool with duplicate Kato-Katz (K-K) thick smears. Prevalence of intestinal schistosomiasis by urine-CCA was 67.4% (95% confidence interval [CI]: 56.5–77.2%) and 35.0% (95% CI: 24.7–46.5%) by K-K. The relationship between faecal eggs per gram (epg) and urine-CCA G-scores (G1 to G10) was assessed by linear regression modelling, finding for every increment in G-score, epg increased by 20.4 (6.50–34.4, P = 0.006). Observed proportions of faecal epg intensities were light (78.6%), moderate (17.9%) and heavy (3.6%). Soil-transmitted helminthiasis was noted, prevalence of ascariasis was 18.8% and trichuriasis was 33.8% (hookworm was not reported). Co-infection of intestinal schistosomiasis and soil-transmitted helminthiasis occurred in 36.3% of PSAC. These results provide solid evidence highlighting the overlooked burden of intestinal schistosomiasis in PSAC, and they also offer technical guidance for better surveillance data for the Madagascan national control programme. ![]()
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Affiliation(s)
- Caitlin Sheehy
- The University of Manchester Medical School, University of Manchester, Manchester, M13 9NT, UK.
| | | | | | - Hannah J Russell
- The University of Manchester Medical School, University of Manchester, Manchester, M13 9NT, UK
| | - Alice Reid
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | | | - Graham Dodge
- Department of Imaging, Brighton and Sussex University Hospital NHS Trust, Brighton, BN2 5BA, UK
| | - Robbie Kornitschky
- The University of Manchester Medical School, University of Manchester, Manchester, M13 9NT, UK
| | - James M StJ Penney
- The University of Manchester Medical School, University of Manchester, Manchester, M13 9NT, UK
| | | | - Antsa Andrianiaina
- Faculté de Médecine, Université D'Antananarivo, Antananarivo, Madagascar
| | - Jenny S Emmanoela
- Faculté de Médecine, Université D'Antananarivo, Antananarivo, Madagascar
| | - Amaya L Bustinduy
- Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, UK
| | - J Russell Stothard
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | | | - Stephen A Spencer
- The University of Manchester Medical School, University of Manchester, Manchester, M13 9NT, UK.,Postgraduate Medical Centre, Royal United Hospitals Bath NHS Foundation Trust, Bath, BA1 3NG, UK
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Yin X, N’Goran EK, Ouattara M, Aka NAD, Diakité NR, Bassa FK, Kourany-Lefoll E, Tappert A, Yalkinoglu Ö, Huber E, Bezuidenhout D, Bagchus WM, Hayward B. Comparison of POC-CCA with Kato-Katz in Diagnosing Schistosoma mansoni Infection in a Pediatric L-Praziquantel Clinical Trial. FRONTIERS IN TROPICAL DISEASES 2021. [DOI: 10.3389/fitd.2021.686288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
IntroductionTraditionally Schistosoma mansoni infection is diagnosed by the Kato-Katz method. Thick smears from each stool sample are prepared on slides and eggs are counted microscopically. Commercially available point-of-care circulating cathodic antigen (POC-CCA) cassette tests detect schistosomiasis antigens from urine samples in 20 minutes. POC-CCA results are qualitative or semi-quantitative: signal intensity is an indicator of the amount of worm antigens in the sample. Both methods were used in a phase II trial investigating the efficacy and safety of new pediatric formulations of praziquantel (PZQ) among children ≤6 years (NCT02806232). This secondary analysis evaluated the consistency of results between the Kato-Katz and POC-CCA methods.MethodsPOC-CCA was used to pre-screen for S. mansoni infection. Children with positive results were tested by the Kato-Katz method, and those with positive Kato-Katz results (>1 egg/1 occurrence) were enrolled. Participants (N=444) were treated with different formulations and doses of PZQ. POC-CCA and Kato-Katz were performed at 2–3 weeks after treatment to evaluate drug efficacy. Cure rate (CR) was defined as the proportion of participants with a negative result per POC-CCA, or no eggs in the stool samples per Kato-Katz. Kappa statistic was used to assess the agreement on cure status, and Spearman correlation between POC-CCA positivity and Kato-Katz egg counts was evaluated. Sensitivity and specificity of POC-CCA were calculated using Kato-Katz as a reference standard.ResultsCR per POC-CCA, measured 2–3 weeks after treatment, was 52% [95% confidence interval (CI): 48%, 57%] across all treatment arms except in infants aged 3–12 months. CR per Kato-Katz was 83% (95% CI: 79%, 87%). Kappa statistic was 0.16 (95% CI: 0.09, 0.23), indicating that the agreement was slightly better than by chance. Relative to Kato-Katz, POC-CCA’s sensitivity to detect infection was 70% and specificity was 57%. Spearman correlation coefficient between POC-CCA positivity and Kato-Katz egg counts was 0.26 (95% CI: 0.17, 0.34).ConclusionPOC-CCA is sensitive and rapid for diagnosing S. mansoni infection, but its performance and consistency with Kato-Katz requires further investigation among young children.
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Graeff-Teixeira C, Favero V, de Souza RP, Pascoal VF, Bittencourt HR, Fukushige M, Geiger SM, Negrão-Corrêa D. Use of Schistosoma mansoni soluble egg antigen (SEA) for antibody detection and diagnosis of schistosomiasis: The need for improved accuracy evaluations of diagnostic tools. Acta Trop 2021; 215:105800. [PMID: 33352167 DOI: 10.1016/j.actatropica.2020.105800] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 11/25/2020] [Accepted: 12/14/2020] [Indexed: 02/08/2023]
Abstract
Many antigens for use in antibody-detection systems for schistosomiasis have been investigated over the past 40 years. In particular, soluble egg antigens (SEA) are still widely used in enzyme-linked immunosorbent assays (ELISAs) for detection of immunoglobulin classes and subclasses. Here, we conducted a literature review to examine accuracy evaluations of SEA-Immunoglobulin G (IgG)-ELISAs performed to detect Schistosoma mansoni infections and published between 1979 and 2019. S. mansoni is the main causative agent for intestinal schistosomiasis in many countries in Africa and Central and South America. After retrieving 214 relevant abstracts from the PubMed database, we selected 15 publications to undergo a full review. Sensitivity and specificity values varied from 71 to 99%, and from 6 to 100%, respectively. In addition, 11/15 studies did not state confidence intervals. Therefore, the findings from this review indicate that after four decades, we still do not have consistent evaluation estimates of SEA-IgG-ELISAs. Antigen mass per well and dilution of test sera in these articles varied from 0.018 µg to 1.5 µg, and from 1:50 to 1:500, respectively. Most of the reported accuracy evaluations used control sera which were selected based on parasitological examinations for egg detection, although ill-defined criteria were also noted. The number and composition of control serum panels was considered not adequate in approximately half of the studies. It is also noteworthy that among more than 30 diagnostic antigen preparations under development since the 1970s, most were not validated in the field and they failed to reach populations in need. Thus, attention to guidelines for standardization, estimations of accuracy, and reporting of results is needed to facilitate coordinated efforts aimed at schistosomiasis control and elimination.
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Kalinda C, Mindu T, Chimbari MJ. A systematic review and meta-analysis quantifying schistosomiasis infection burden in pre-school aged children (PreSAC) in sub-Saharan Africa for the period 2000-2020. PLoS One 2020; 15:e0244695. [PMID: 33373405 PMCID: PMC7771669 DOI: 10.1371/journal.pone.0244695] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 12/14/2020] [Indexed: 12/22/2022] Open
Abstract
INTRODUCTION Following the adoption of the World Health Assembly Resolution WHA 65.21 and Neglected Tropical Diseases road map 2021-2030, schistosomiasis control programmes have shifted from morbidity control to disease elimination. However, several gaps continue to be observed in the implementation of control programmes with certain age groups omitted from these campaigns increasing health inequalities and risks of reinfections to previously treated groups. We used the Inverse Variance Heterogeneity (IVhet) model to estimate the prevalence of schistosomiasis infection among preschool-aged children. METHODS We did a systematic review of peer-reviewed literature on schistosomiasis in sub-Saharan Africa for the period January 1, 2000 to November 30, 2020. Quantitative data for cases of schistosomiasis infection were extracted, including country and region where the studies were done, year of publication and specific schistosome species observed. The IVhet model was used to estimate the pooled prevalence estimate (PPE), the heterogeneity and publication bias. RESULTS We screened 2601 articles to obtain 47 eligible studies containing quantitative data on preschool-aged children. Of the selected studies, 44.7% (n = 22) were from East Africa while the least number of studies obtained (2.1%, n = 1) was from Central Africa. 21712 subjects were screened for infection due to Schistosoma spp; 13924 for S. mansoni and 7788 for S. haematobium. The PPE for schistosomiasis among PreSAC was 19% (95% CI: 11-28). Infection due to S. mansoni (IVhet PPE: 22% (95% CI: 9-36) was higher than that due to S. haematobium (15%; 95% CI: 6-25). A Luis Furuya-Kanamori index of 1.83 indicated a lack of publication bias. High level of heterogeneity was observed (I2 > 90%) and this could not be reduced through subgroup analysis. CONCLUSION Schistosomiasis infection among pre-school aged children 6 years old and below is high. This indicates the importance of including this age group in treatment programmes to reduce infection prevalence and long-term morbidities associated with prolonged schistosome infection.
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Affiliation(s)
- Chester Kalinda
- University of Namibia, Katima Mulilo, Namibia
- Department of Public Health, College of Health Sciences, School of Nursing and Public Health, University of KwaZulu-Natal, Durban, South Africa
| | - Tafadzwa Mindu
- Department of Public Health, College of Health Sciences, School of Nursing and Public Health, University of KwaZulu-Natal, Durban, South Africa
| | - Moses John Chimbari
- Department of Public Health, College of Health Sciences, School of Nursing and Public Health, University of KwaZulu-Natal, Durban, South Africa
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Hoekstra PT, Schwarz NG, Adegnika AA, Andrianarivelo MR, Corstjens PLAM, Rakotoarivelo RA, Rakotozandrindrainy R, Sicuri E, Kreidenweiss A, van Dam GJ. Fast and reliable easy-to-use diagnostics for eliminating bilharzia in young children and mothers: An introduction to the freeBILy project. Acta Trop 2020; 211:105631. [PMID: 32679109 DOI: 10.1016/j.actatropica.2020.105631] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 06/24/2020] [Accepted: 07/13/2020] [Indexed: 02/07/2023]
Abstract
Schistosoma antigen detection tests have a large potential for schistosomiasis control programs due to their ability to detect active and ongoing Schistosoma infections, their much higher sensitivity compared to microscopical methods, and the possibility to use non-invasive urine samples. Pregnant women and young children could especially benefit from affordable and easy-to-use antigen tests as inclusion of these vulnerable groups in mass drug administration campaigns will always require higher justification hurdles, especially in low to middle endemic regions with a higher proportion of individuals who are not infected and thus unnecessarily exposed to praziquantel. The overall objective of the 'fast and reliable easy-to-use diagnostics for eliminating bilharzia in young children and mothers' (freeBILy, www.freeBILy.eu) project is to thoroughly evaluate the point-of-care circulating cathodic antigen (POC-CCA) and the up-converting phosphor reporter particle, lateral flow circulating anodic antigen (UCP-LF CAA) urine strip tests to diagnose Schistosoma infections in pregnant women and young children and to assess their potential as a schistosomiasis control tool in test-and-treat strategies. The freeBILy project will generate valuable, evidence-based findings on improved tools and test-and-treat strategies to reduce the burden of schistosomiasis in pregnant women and young children.
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Affiliation(s)
- Pytsje T Hoekstra
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands.
| | - Norbert G Schwarz
- Bernhard-Nocht-Institut für Tropenmedizin, Hamburg, Germany; German Center for Infection Research, Germany
| | - Ayola A Adegnika
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands; German Center for Infection Research, Germany; Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon; Eberhard Karls Universität Tübingen, Tübingen, Germany
| | | | - Paul L A M Corstjens
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands
| | | | | | - Elisa Sicuri
- ISGlobal, Hospital Clínic, Universitat de Barcelona, Barcelona, Spain; Health Economics Group, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, UK
| | - Andrea Kreidenweiss
- German Center for Infection Research, Germany; Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Govert J van Dam
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
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9
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Favero V, Veríssimo CDM, Piovesan AR, Morassutti AL, Souto AA, Bittencourt HR, Pascoal VF, Lindholz CG, Jones MK, Souza RP, Rigo FDV, Carlini CR, Graeff-Teixeira C. A new diagnostic strategy which uses a luminol-H2O2 system to detect helminth eggs in fecal sediments processed by the Helmintex method. PLoS Negl Trop Dis 2020; 14:e0008500. [PMID: 32730339 PMCID: PMC7437924 DOI: 10.1371/journal.pntd.0008500] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 08/19/2020] [Accepted: 06/18/2020] [Indexed: 11/19/2022] Open
Abstract
Schistosomiasis remains a serious public health problem in tropical regions, affecting more than 250 million people. Sensitive diagnostic methods represent key tools for disease elimination, in particular in areas with low endemicity. Advances in the use of luminol-based chemiluminescent techniques have enabled greater sensitivity and speed in obtaining results in different diagnostic settings. In this study, we developed a luminol-H2O2 chemiluminescence (CL) method to detect Schistosoma mansoni eggs in human fecal sediments processed by the Helmintex (HTX) method. After S. mansoni eggs were incubated with a solution of luminol-H2O2 the light emission was detected and measured by spectrophotometry at 431 nm for 5 min, using detection and counts of eggs by bright field optical microscopy as a reference. CL intensity was found to correlate with different sources and numbers of eggs. Furthermore, our results showed that the CL method can distinguish positive from negative samples with 100% sensitivity and 71% specificity. To our knowledge, this is the first study to report the use of CL for the diagnosis of helminths from fecal samples. The combination of the HTX method with CL represents an important advance in providing a reference method with the highest standards of sensitivity. Schistosomiasis, the infection caused by parasites of the genus Schistosoma, is still a significant health problem in many countries, despite some successful control efforts. In areas where parasite load is low and few eggs are released in feces, most diagnostic tests fail to detect the infections. Helmintex is a very sensitive, but time consuming, egg-detection method, with most time being consumed in observations of samples at the microscope. Here we report standardization of an innovative luminol-H2O2 chemiluminescence reaction triggered by Schistosoma mansoni eggs that may improve their detection in feces. Improved diagnostic tests are urgently required as part of the schistosomiasis elimination efforts.
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Affiliation(s)
- Vivian Favero
- Research Group on Biomedical Parasitology, School of health and life sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
- Neurotoxins Laboratory (LaNeuroTox), School of Medicine, Brain Institute and School of Medicine, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
- * E-mail:
| | - Carolina De Marco Veríssimo
- Research Group on Biomedical Parasitology, School of health and life sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
- Centre for One Health and Ryan Institute, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Angela R. Piovesan
- Neurotoxins Laboratory (LaNeuroTox), School of Medicine, Brain Institute and School of Medicine, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
- Graduate Program in Cellular and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Alessandra L. Morassutti
- Research Group on Biomedical Parasitology, School of health and life sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - André A. Souto
- Polytechnic School, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Hélio R. Bittencourt
- Polytechnic School, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Vanessa F. Pascoal
- Research Group on Biomedical Parasitology, School of health and life sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Catieli G. Lindholz
- Research Group on Biomedical Parasitology, School of health and life sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Malcolm K. Jones
- School of Veterinary Science, The University of Queensland, Brisbane, Qld, Australia, 4072
| | - Renata P. Souza
- Research Group on Biomedical Parasitology, School of health and life sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Francine De Vargas Rigo
- Research Group on Biomedical Parasitology, School of health and life sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Célia R. Carlini
- Neurotoxins Laboratory (LaNeuroTox), School of Medicine, Brain Institute and School of Medicine, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Carlos Graeff-Teixeira
- Research Group on Biomedical Parasitology, School of health and life sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
- Infectious Diseases Unit, Center for Health Sciences, Federal University of Espirito Santo, Vitoria, Brazil
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Abstract
Background: Schistosomiasis has continued to plague low-resource areas of the Nigerian population. Mass drug administration (MDA) has been the only adopted interventional program for decades. However, it appears this effort does not culminate in transmission and morbidity reduction. Purpose: To highlight the current situation of schistosomiasis in Nigeria, why MDA alone cannot achieve the expected result, identify research needs, and promotion of integrated control approach for schistosomiasis. Method: A viewpoint based on practices, research findings, and personal and professional experience in the field of schistosomiasis control. Conclusion: This viewpoint strongly advocates a commitment to the integrated control approach through the development of robust schistosomiasis control policy for the country. It stressed the need for research priorities in neglected areas of schistosomiasis that are germane for control of the disease. The government’s willpower to implement important recommendations from research outcomes is important to achieve success.
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11
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Olliaro PL, Coulibaly JT, Garba A, Halleux C, Keiser J, King CH, Mutapi F, N’Goran EK, Raso G, Scherrer AU, Sousa-Figueiredo JC, Stete K, Utzinger J, Vaillant MT. Efficacy and safety of single-dose 40 mg/kg oral praziquantel in the treatment of schistosomiasis in preschool-age versus school-age children: An individual participant data meta-analysis. PLoS Negl Trop Dis 2020; 14:e0008277. [PMID: 32569275 PMCID: PMC7360067 DOI: 10.1371/journal.pntd.0008277] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 07/14/2020] [Accepted: 04/08/2020] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Better knowledge of the efficacy and safety of single-dose 40 mg/kg oral praziquantel in preschool-age children is required, should preventive chemotherapy programs for schistosomiasis be expanded to include this age group. METHODOLOGY We analyzed individual participant-level data from 16 studies (13 single-arm or cohort studies and three randomized trials), amounting to 683 preschool-age children (aged <6 years) and 2,010 school-age children (aged 6-14 years). Children had a documented Schistosoma mansoni or S. haematobium infection, were treated with single 40 mg/kg oral praziquantel, and assessed between 21 and 60 days post-treatment. Efficacy was expressed as arithmetic mean and individual egg reduction rate (ERR) and meta-analyzed using general linear models and mixed models. Safety was summarized using reported adverse events (AEs). PRINCIPAL FINDINGS Preschool-age children had significantly lower baseline Schistosoma egg counts and more losses to follow-up compared to school-age children. No difference in efficacy was found between preschool- and school-age children using a general linear model of individual-participant ERR with baseline log-transformed egg count as covariate and study, age, and sex as fixed variables, and a mixed model with a random effect on the study. Safety was reported in only four studies (n = 1,128 individuals); few AEs were reported in preschool-age children 4 and 24 hours post-treatment as well as at follow-up. Three severe but not serious AEs were recorded in school-age children during follow-up. CONCLUSIONS/SIGNIFICANCE There is no indication that single-dose 40 mg/kg oral praziquantel would be less efficacious and less safe in preschool-age children compared to school-age children, with the caveat that only few randomized comparisons exist between the two age groups. Preventive chemotherapy might therefore be extended to preschool-age children, with proper monitoring of its efficacy and safety.
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Affiliation(s)
- Piero L. Olliaro
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Jean T. Coulibaly
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
| | - Amadou Garba
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Christine Halleux
- UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR), World Health Organization, Geneva, Switzerland
| | - Jennifer Keiser
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - 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
| | - Francisca Mutapi
- NIHR Global Health Research Unit Tackling Infections to Benefit Africa (TIBA), Ashworth Laboratories, University of Edinburgh, Edinburgh, United Kingdom
- Institute of Immunology and Infection Research, Centre for Immunity, Infection and Evolution, School of Biological Sciences, Ashworth Laboratories, University of Edinburgh, Edinburgh, United Kingdom
| | - Eliézer K. N’Goran
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
| | - Giovanna Raso
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Alexandra U. Scherrer
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - José Carlos Sousa-Figueiredo
- Department of Life Sciences, Natural History Museum, Wolfson Wellcome Biomedical Laboratories, London, United Kingdom
- Centro de Investigação em Saúde de Angola, Hospital Provincial, Bengo, Angola
| | - Katarina Stete
- Division of Infectious Diseases, Department of Medicine II, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Michel T. Vaillant
- Centre of Competences for Methodology and Statistics, Luxembourg Institute of Health, Strassen, Luxembourg
- * E-mail:
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12
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Faust CL, Osakunor DNM, Downs JA, Kayuni S, Stothard JR, Lamberton PHL, Reinhard-Rupp J, Rollinson D. Schistosomiasis Control: Leave No Age Group Behind. Trends Parasitol 2020; 36:582-591. [PMID: 32430274 DOI: 10.1016/j.pt.2020.04.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/15/2020] [Accepted: 04/17/2020] [Indexed: 01/11/2023]
Abstract
Despite accelerating progress towards schistosomiasis control in sub-Saharan Africa, several age groups have been eclipsed by current treatment and monitoring strategies that mainly focus on school-aged children. As schistosomiasis poses a threat to people of all ages, unfortunate gaps exist in current treatment coverage and associated monitoring efforts, preventing subsequent health benefits to preschool-aged children as well as certain adolescents and adults. Expanding access to younger ages through the forthcoming pediatric praziquantel formulation and improving treatment coverage in older ages is essential. This should occur alongside formal inclusion of these groups in large-scale monitoring and evaluation activities. Current omission of these age groups from treatment and monitoring exacerbates health inequities and has long-term consequences for sustainable schistosomiasis control.
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Affiliation(s)
- Christina L Faust
- Wellcome Centre for Integrative Parasitology, Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK.
| | - Derick N M Osakunor
- Institute of Immunology and Infection Research, University of Edinburgh, Ashworth Laboratories, King's Buildings, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK
| | - Jennifer A Downs
- Center for Global Health, Department of Medicine, Weill Cornell Medicine, New York, NY 10065, USA
| | - Sekeleghe Kayuni
- Department of Tropical Disease Biology, Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK; MASM Medi Clinics Limited, Medical Aid Society of Malawi (MASM), Blantyre, Malawi
| | - J Russell Stothard
- Department of Tropical Disease Biology, Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Poppy H L Lamberton
- Wellcome Centre for Integrative Parasitology, Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | | | - David Rollinson
- Global Schistosomiasis Alliance, Natural History Museum, London SW7 5BD, UK
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13
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Detecting Schistosoma mansoni infections among pre-school-aged children in southern Ghana: a diagnostic comparison of urine-CCA, real-time PCR and Kato-Katz assays. BMC Infect Dis 2020; 20:301. [PMID: 32321418 PMCID: PMC7178570 DOI: 10.1186/s12879-020-05034-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 04/15/2020] [Indexed: 11/16/2022] Open
Abstract
Background In Ghana, pre-school-aged children (PSAC) are at risk of intestinal schistosomiasis and are living in need of praziquantel treatment. To better assess the infection burden within this vulnerable demographic group, we have provided a comparative assessment of the prevalence of Schistosoma mansoni in pre-school-aged children by urine circulating cathodic antigen (CCA) dipsticks, real-time PCR Taqman® faecal assays and Kato-Katz coproscopy. Methods In all, 190 pre-school-aged children were sampled from three endemic communities (viz. Tomefa, Torgahkope/Adakope, and Manheam) around Weija dam, Southern Ghana. Fresh stool and urine samples were collected from all participants for diagnosis. Results Among all the three communities, the urine-CCA assay recorded the highest prevalence values of 90.5% (95% CI 80.4–96.4), 87.9% (95% CI 76.7–95), and 81.2% (95% CI 69.9–89.6) in Tomefa, Torgahkope/Adakope, and Manheam respectively. Prevalence by real-time PCR was 50% (95% CI 35.5–64.5), 8% (95% CI 2.2–19.2) and 16.7% (95% CI 8.3–28.5), while by Kato-Katz was 55.6% (95% CI 42.5–68.1), 8.6% (95% CI 2.9–19) and 11.6% (95% CI 5.1–21.6) respectively. Children aged 1 year and over were found to be positive with the urine-CCA assay; by the ages of 3–4, over 50% were urine-CCA patent. The sensitivity and specificity of the POC-CCA dipsticks, when compared against the combined results of Kato-Katz/TaqMan results was found to be 84.1% (95% CI = 72.7–92.1) and 12.9% (95% CI = 6.6–22) respectively. Conclusions We propose that the urine-CCA dipstick may be a useful rapid diagnostic tool to estimate the prevalence of intestinal schistosomiasis in PSAC, particularly in rapid identification of at-risk areas. However, our assessment has shown that it possible to record false positives when compared to combined Kato-Katz and qPCR results. To guide PSAC praziquantel treatment needs, we propose the urine CCA assay should be included in routine surveillance of intestinal schistosomiasis alongside other diagnostics such as Kato-Katz and urine filtration.
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Nigo MM, Salieb-Beugelaar G, Battegay M, Odermatt P, Hunziker P. Schistosomiasis: from established diagnostic assays to emerging micro/nanotechnology-based rapid field testing for clinical management and epidemiology. PRECISION NANOMEDICINE 2019. [DOI: 10.33218/prnano3(1).191205.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Schistosomiasis is a neglected invasive worm disease with a huge disease burden in developing countries, particularly in children, and is seen increasingly in non-endemic regions through transfer by travellers, expatriates, and refugees. Undetected and untreated infections may be responsible for the persistence of transmission. Rapid and accurate diagnosis is the key to treatment and control. So far, parasitological detection methods remain the cornerstone of Schistosoma infection diagnosis in endemic regions, but conventional tests have limited sensitivity, in particular in low-grade infection. Recent advances contribute to improved detection in clinical and field settings. The recent progress in micro- and nanotechnologies opens a road by enabling the design of new miniaturized point-of-care devices and analytical platforms, which can be used for the rapid detection of these infections. This review starts with an overview of currently available laboratory tests and their performance and then discusses emerging rapid and micro/nanotechnologies-based tools. The epidemiological and clinical setting of testing is then discussed as an important determinant for the selection of the best analytical strategy in patients suspected to suffer from Schistosoma infection. Finally, it discusses the potential role of advanced technologies in the setting near to disease eradication is examined.
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Affiliation(s)
| | | | | | - Peter Odermatt
- Swiss Tropical and Public Health Institute, Basel, Switzerland
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15
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Sacolo-Gwebu H, Chimbari M, Kalinda C. Prevalence and risk factors of schistosomiasis and soil-transmitted helminthiases among preschool aged children (1-5 years) in rural KwaZulu-Natal, South Africa: a cross-sectional study. Infect Dis Poverty 2019; 8:47. [PMID: 31202273 PMCID: PMC6571117 DOI: 10.1186/s40249-019-0561-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 05/28/2019] [Indexed: 02/17/2023] Open
Abstract
Background Despite efforts to control neglected tropical diseases (NTDs), schistosomiasis and soil-transmitted helminthiases remain widely prevalent in sub-Saharan Africa. Recent data suggest that these infections are prevalent among preschool aged children (PSAC) in poor communities. Evidence of schistosomiasis and soil-transmitted helminths (STH) infection patterns and prevalence among PSAC is essential for effective treatment and control programmes. The aim of the study was to determine the prevalence, intensity and risk factors of schistosomiasis and STH infection among PSAC in the Ingwavuma area of uMkhanyakude District, South Africa. Methods A cross-sectional study was conducted among 1143 PSAC aged 1–5 years in 34 preschools and early childhood development (ECD) centres. Data on risk factors was collected using a semi-structured questionnaire. A Kruskal–Wallis test was used to compare the differences in infection intensity with age. Pearson Chi-square test and multivariate logistic regression were performed to assess the association between PSAC infection status, sociodemographic, household, water and sanitation variables and hygiene practices of PSAC and their caregivers. Results We observed a low prevalence of Schistosoma haematobium (1.0%) and S. mansoni (0.9%). The prevalence of Ascaris lumbricoides (18.3%) was high compared to Trichuris trichiura (1.2%), hookworms (1.6%) and Taenia (6.4%). The odds of schistosome infection were lowest among PSAC under younger (15–24 years) caregivers (0.1, 95% CI: 0.02–0.54) and those who used tap water (0.3, 95% CI: 0.09–0.78) for domestic purposes. Schistosome infection was however higher among PSAC who bathed in river water (17.4, 95% CI: 5.96–51.04). STH infection on the other hand was lowest among PSAC who did not play in soil (0.1, 95% CI: 0.51–0.28), were from households that used tap water for domestic purposes (0.5, 95% CI: 0.27–0.80) and PSAC under the care of younger (25–35 years) caregivers (0.3, 95% CI: 0.10–0.75). The risk of STH infection was highest among PSAC who did not wash their hands with soap (3.5, 95% CI: 1.04–11.67) and PSAC whose nails were not trimmed (3.6, 95% CI: 1.75–7.26). Conclusions The findings show low prevalence and infection intensity of schistosomiasis and STH infection except A. lumbricoides among PSAC. Factors predicting schistosomiasis and STH infection among PSAC were related to caregivers’ age, educational status, water and hygiene practices. STH infection was exclusively associated with PSAC playing and handwashing habits. These findings highlight the need to include PSAC caregivers in schistosomiasis and STH prevention and control programmes. Electronic supplementary material The online version of this article (10.1186/s40249-019-0561-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hlengiwe Sacolo-Gwebu
- School of Nursing and Public Health, College of Health Sciences, University of KwaZulu-Natal, Howard Campus, Durban, South Africa.
| | - Moses Chimbari
- School of Nursing and Public Health, College of Health Sciences, University of KwaZulu-Natal, Howard Campus, Durban, South Africa
| | - Chester Kalinda
- School of Nursing and Public Health, College of Health Sciences, University of KwaZulu-Natal, Howard Campus, Durban, South Africa.,University of Namibia, Katima Mulilo Campus, Winela Road, Box 1096, Katima Mulilo, Namibia
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16
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Tweyongyere R, Nassanga BR, Muhwezi A, Odongo M, Lule SA, Nsubuga RN, Webb EL, Cose SC, Elliott AM. Effect of Schistosoma mansoni infection and its treatment on antibody responses to measles catch-up immunisation in pre-school children: A randomised trial. PLoS Negl Trop Dis 2019; 13:e0007157. [PMID: 30763405 PMCID: PMC6392333 DOI: 10.1371/journal.pntd.0007157] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 02/27/2019] [Accepted: 01/14/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Schistosoma infection is associated with immune modulation that can influence responses to non-schistosome antigens. Vaccine responses may be impaired in S. mansoni-infected individuals. We investigated effects of S. mansoni infection on responses to childhood measles catch-up immunisation and of praziquantel treatment on this outcome in a randomised trial. METHODOLOGY The Immune Modulation and Childhood Immunisation (IMoChI) study was based in Entebbe, Uganda. Children aged 3-5 years (193 S. mansoni-infected and 61 uninfected) were enrolled. Infected children were randomised in a 1:1:1 ratio to receive praziquantel 2 weeks before, at time of, or 1 week after, measles catch-up immunisation. Plasma anti-measles IgG was measured at enrolment, 1 week and 24 weeks after measles immunisation. Primary outcomes were IgG levels and percentage of participants with levels considered protective against measles. RESULTS Anti-measles IgG levels increased following immunisation, but at 1 week post-immunisation S. mansoni-infected, compared to uninfected, children had lower levels of anti-measles IgG (adjusted geometric mean ratio (aGMR) 0.4 [95% CI 0.2-0.7]) and the percentage with protective antibody levels was also lower (adjusted odds ratio 0.1 [0-0.9]). Among S. mansoni-infected children, anti-measles IgG one week post-immunisation was higher among those treated with praziquantel than among those who were not yet treated (treatment before immunisation, aGMR 2.3 [1.5-4.8]; treatment at immunisation aGMR 1.8 [1.1-3.5]). At 24 weeks post-immunisation, IgG levels did not differ between the trial groups, but tended to be lower among previously-infected children who were still S mansoni stool-positive than among those who became stool-negative. CONCLUSIONS AND SIGNIFICANCE Our findings suggest that S. mansoni infection among pre-school children is associated with a reduced antibody response to catch-up measles immunisation, and that praziquantel treatment improves the response. S. mansoni infection may contribute to impaired vaccine responses in endemic populations; effective schistosomiasis control may be beneficial for vaccine efficacy. This should be further explored. TRIAL REGISTRATION ISRCTN87107592.
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Affiliation(s)
- Robert Tweyongyere
- Department of Veterinary Pharmacy Clinical and Comparative Medicine, Makerere University, Kampala, Uganda
- Medical Research Council/Uganda Virus Research Institute and London School of Hygiene & Tropical Medicine Uganda Research Unit, Entebbe, Uganda
| | - Beatrice R. Nassanga
- Medical Research Council/Uganda Virus Research Institute and London School of Hygiene & Tropical Medicine Uganda Research Unit, Entebbe, Uganda
| | - Allan Muhwezi
- Medical Research Council/Uganda Virus Research Institute and London School of Hygiene & Tropical Medicine Uganda Research Unit, Entebbe, Uganda
| | - Matthew Odongo
- Medical Research Council/Uganda Virus Research Institute and London School of Hygiene & Tropical Medicine Uganda Research Unit, Entebbe, Uganda
| | - Swaib A. Lule
- Medical Research Council/Uganda Virus Research Institute and London School of Hygiene & Tropical Medicine Uganda Research Unit, Entebbe, Uganda
| | - Rebecca N. Nsubuga
- Medical Research Council/Uganda Virus Research Institute and London School of Hygiene & Tropical Medicine Uganda Research Unit, Entebbe, Uganda
| | - Emily L. Webb
- London School of Hygiene & Tropical Medicine, Keppel Street, London United Kingdom
| | - Stephen C. Cose
- Medical Research Council/Uganda Virus Research Institute and London School of Hygiene & Tropical Medicine Uganda Research Unit, Entebbe, Uganda
- London School of Hygiene & Tropical Medicine, Keppel Street, London United Kingdom
| | - Alison M. Elliott
- Medical Research Council/Uganda Virus Research Institute and London School of Hygiene & Tropical Medicine Uganda Research Unit, Entebbe, Uganda
- London School of Hygiene & Tropical Medicine, Keppel Street, London United Kingdom
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17
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Castro VN, Rodrigues JL, Cardoso DT, Resende SD, Magalhães FC, Souza DC, Requeijo MH, Negrão-Corrêa D, Geiger SM. Systemic Cytokine and Chemokine Profiles in Individuals With Schistosoma mansoni Infection and Low Parasite Burden. Front Immunol 2018; 9:2975. [PMID: 30619332 PMCID: PMC6305627 DOI: 10.3389/fimmu.2018.02975] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 12/04/2018] [Indexed: 11/13/2022] Open
Abstract
Intestinal schistosomiasis, caused by the parasitic trematode Schistosoma mansoni, is a chronic disease and the prolonged and continuous exposure to S. mansoni antigens results in a deviation of the host's immune response. For diagnosis, the Kato-Katz (KK) method is recommended, however, this method showed low accuracy in areas of low endemicity. This study aimed to characterize the cytokine and chemokine profile of individuals with an extremely low parasite load (<4 eggs per gram of feces), e.g., individuals who were detected by alternative parasitological methods, such as the saline gradient and/or Helmintex®. In order to search for immunological markers for infection, the immunological profile in serum samples of these individuals was then compared with patients detected with the KK method and with a higher parasite load and with individuals repetitively negative by extensive stool exams. The study was conducted in Northern Minas Gerais in a rural area of the Municipality of Januária. Serum samples of a total of 139 parasitologically well-characterized individuals were assessed for the following immunological markers by commercially available immunoassays: TNF-α, IL-1β, IL-6, IL-17A, IL-5, IL-10, IL-13, IL-33, IL-27, CCL3, CCL5, CXCL10, CCL11, and CCL17. As a result, there were no significant differences in concentrations or frequencies for immunological markers between egg-negative individuals or individuals with ultra-low (<4 epg) or low (4-99 epg) parasite loads. However, we found significant correlations between egg counts and eosinophil counts and between egg counts and IL-1β or TNF-α concentrations. The most striking alterations were found in individuals with the highest parasite load (≥100 epg). They had significantly higher TNF-α concentrations in serum when compared with individuals with a low parasite load (4-99 epg) and CCL17 concentrations were significantly elevated when compared with egg-negative individuals. Radar diagrams of frequencies for cytokine and chemokine responders in each infection group confirmed a distinct profile only in the infection group with highest parasite loads (≥100 epg).
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Affiliation(s)
- Vanessa N. Castro
- Department of Parasitology, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Jailza L. Rodrigues
- Department of Parasitology, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Diogo T. Cardoso
- Department of Parasitology, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Samira D. Resende
- Department of Parasitology, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Fernanda C. Magalhães
- Department of Parasitology, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Dayane C. Souza
- Department of Parasitology, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Maira H. Requeijo
- Faculdade da Saúde e Ecologia Humana (FASEH) Vespasiano, Belo Horizonte, Brazil
| | - Deborah Negrão-Corrêa
- Department of Parasitology, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Stefan M. Geiger
- Department of Parasitology, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
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18
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Blanton RE. Population Genetics and Molecular Epidemiology of Eukaryotes. Microbiol Spectr 2018; 6:10.1128/microbiolspec.AME-0002-2018. [PMID: 30387414 PMCID: PMC6217834 DOI: 10.1128/microbiolspec.ame-0002-2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Indexed: 01/16/2023] Open
Abstract
Molecular epidemiology uses the distribution and organization of a pathogen's DNA to understand the distribution and determinants of disease. Since the biology of DNA for eukaryotic pathogens differs substantially from that of bacteria, the analytic approach to their molecular epidemiology can also differ. While many of the genotyping techniques presented earlier in this series, "Advances in Molecular Epidemiology of Infectious Diseases," can be applied to eukaryotes, the output must be interpreted in the light of how DNA is distributed from one generation to the next. In some cases, parasite populations can be evaluated in ways reminiscent of bacteria. They differ, however, when analyzed as sexually reproducing organisms, where all individuals are unique but the genetic composition of the population does not change unless a limited set of events occurs. It is these events (migration, mutation, nonrandom mating, selection, and genetic drift) that are of interest. At a given time, not all of them are likely to be equally important, so the list can easily be narrowed down to understand the driving forces behind the population as it is now and even what it will look like in the future. The main population characteristics measured to assess these events are differentiation and diversity, interpreted in the light of what is known about the population from observation. The population genetics of eukaryotes is important for planning and evaluation of control measures, surveillance, outbreak investigation, and monitoring of the development and spread of drug resistance. *This article is part of a curated collection.
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Affiliation(s)
- Ronald E Blanton
- Center for Global Health & Diseases, Case Western Reserve University, Cleveland, OH 44106
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19
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Abstract
Schistosomiasis (bilharzia) is a neglected tropical disease caused by parasitic flatworms (blood flukes) of the genus Schistosoma, with considerable morbidity in parts of the Middle East, South America, Southeast Asia and, particularly, in sub-Saharan Africa. Infective larvae grow in an intermediate host (fresh-water snails) before penetrating the skin of the definitive human host. Mature adult worms reside in the mesenteric (Schistosoma mansoni and Schistosoma japonicum) or pelvic (Schistosoma haematobium) veins, where female worms lay eggs, which are secreted in stool or urine. Eggs trapped in the surrounding tissues and organs, such as the liver and bladder, cause inflammatory immune responses (including granulomas) that result in intestinal, hepato-splenic or urogenital disease. Diagnosis requires the detection of eggs in excreta or worm antigens in the serum, and sensitive, rapid, point-of-care tests for populations living in endemic areas are needed. The anti-schistosomal drug praziquantel is safe and efficacious against adult worms of all the six Schistosoma spp. infecting humans; however, it does not prevent reinfection and the emergence of drug resistance is a concern. Schistosomiasis elimination will require a multifaceted approach, including: treatment; snail control; information, education and communication; improved water, sanitation and hygiene; accurate diagnostics; and surveillance-response systems that are readily tailored to social-ecological settings.
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Affiliation(s)
- Donald P McManus
- Immunology Department, QIMR Berghofer Medical Research Institute, Herston, Brisbane, Queensland, Australia.
| | - David W Dunne
- Department of Pathology, University of Cambridge, Cambridge, UK
| | - Moussa Sacko
- Department of Diagnostic and Biomedical Research, Institut National de Recherche en Santé Publique, Bamako, Mali
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Birgitte J Vennervald
- Department of Veterinary and Animal Science, University of Copenhagen, Copenhagen, Denmark
| | - Xiao-Nong Zhou
- National Institute of Parasitic Diseases, Shanghai, People's Republic of China
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20
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Okoyo C, Simiyu E, Njenga SM, Mwandawiro C. Comparing the performance of circulating cathodic antigen and Kato-Katz techniques in evaluating Schistosoma mansoni infection in areas with low prevalence in selected counties of Kenya: a cross-sectional study. BMC Public Health 2018; 18:478. [PMID: 29642875 PMCID: PMC5896080 DOI: 10.1186/s12889-018-5414-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 04/05/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Kato-Katz technique has been the mainstay test in Schistosoma mansoni diagnosis in endemic areas. However, recent studies have documented its poor sensitivity in evaluating Schistosoma mansoni infection especially in areas with lower rates of transmission. It's the primary diagnostic tool in monitoring impact of the Kenya national school based deworming program on infection transmission, but there is need to consider a more sensitive technique as the prevalence reduces. Therefore, this study explored the relationship between results of the stool-based Kato-Katz technique with urine-based point-of-care circulating cathodic antigen (POC-CCA) test in view to inform decision-making by the program in changing from Kato-Katz to POC-CCA test. METHODS We used two cross-sectional surveys conducted pre- and post- mass drug administration (MDA) using praziquantel in a representative random sample of children from 18 schools across 11 counties. A total of 1944 children were randomly sampled for the study. Stool and urine samples were tested for S. mansoni infection using Kato-Katz and POC-CCA methods, respectively. S. mansoni prevalence using each technique was calculated and 95% confidence intervals obtained using binomial regression model. Specificity (Sp) and sensitivity (Sn) were determined using 2 × 2 contingency tables and compared using the McNemar's chi-square test. RESULTS A total of 1899 and 1878 children were surveyed at pre- and post-treatment respectively. S. mansoni infection prevalence was 26.5 and 21.4% during pre- and post-treatment respectively using POC-CCA test, and 4.9 and 1.5% for pre- and post-treatment respectively using Kato-Katz technique. Taking POC-CCA as the gold standard, Kato-Katz was found to have significantly lower sensitivity both at pre- and post-treatment, Sn = 12.5% and Sn = 5.2% respectively, McNemar test χ2m = 782.0, p < 0.001. In overall, the results showed a slight/poor agreement between the two methods, kappa index (k) = 0.11, p < 0.001, inter-rater agreement = 77.1%. CONCLUSIONS Results showed POC-CCA technique as an effective, sensitive and accurate screening tool for Schistosoma mansoni infection in areas of low prevalence. It was up to 14-fold accurate than Kato-Katz which had extremely inadequate sensitivity. We recommend usage of POC-CCA alongside Kato-Katz examinations by Schistosomiasis control programs in low prevalence areas.
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Affiliation(s)
- Collins Okoyo
- Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute (KEMRI), P.O. Box 54840 - 00200, Nairobi, Kenya.
| | - Elses Simiyu
- Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute (KEMRI), P.O. Box 54840 - 00200, Nairobi, Kenya
| | - Sammy M Njenga
- Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute (KEMRI), P.O. Box 54840 - 00200, Nairobi, Kenya
| | - Charles Mwandawiro
- Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute (KEMRI), P.O. Box 54840 - 00200, Nairobi, Kenya
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21
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Seroepidemiology of helminths and the association with severe malaria among infants and young children in Tanzania. PLoS Negl Trop Dis 2018; 12:e0006345. [PMID: 29579050 PMCID: PMC5886694 DOI: 10.1371/journal.pntd.0006345] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 04/05/2018] [Accepted: 02/24/2018] [Indexed: 01/23/2023] Open
Abstract
The disease burden of Wuchereria bancrofti and Plasmodium falciparum malaria is high, particularly in Africa, and co-infection is common. However, the effects of filarial infection on the risk of severe malaria are unknown. We used the remaining serum samples from a large cohort study in Muheza, Tanzania to describe vector-borne filarial sero-reactivity among young children and to identify associations between exposure to filarial parasites and subsequent severe malaria infections. We identified positive filarial antibody responses (as well as positive antibody responses to Strongyloides stercoralis) among infants as young as six months. In addition, we found a significant association between filarial seropositivity at six months of age and subsequent severe malaria. Specifically, infants who developed severe malaria by one year of age were 3.9 times more likely (OR = 3.9, 95% CI: 1.2, 13.0) to have been seropositive for filarial antigen at six months of age compared with infants who did not develop severe malaria. In this paper, we used a multiplexed, serologic assessment to identify children with previous or current exposure to or infection with filarial parasites or S. stercoralis (a soil transmitted helminth), enhancing our understanding of co-infections in early childhood. We identified an increasing prevalence of filarial antibodies over time in a population of children as young as 6 months old. In addition, we found a significant association between filarial seropositivity at six months of age and subsequent severe malaria.
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22
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Bustinduy AL, Stothard JR, Friedman JF. Paediatric and maternal schistosomiasis: shifting the paradigms. Br Med Bull 2017; 123:115-125. [PMID: 28910994 PMCID: PMC6279106 DOI: 10.1093/bmb/ldx028] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 07/16/2017] [Indexed: 11/13/2022]
Abstract
BACKGROUND In endemic areas, schistosomiasis causes both overt and subclinical disease in young children and their mothers, as well as in returned travellers. SOURCES OF DATA Key recently published literature. AREAS OF AGREEMENT An action plan for paediatric schistosomiasis and female genital schistosomiasis (FGS) is needed with expanded access to praziquantel (PZQ) treatment required. AREAS OF CONTROVERSY Schistosomiasis-related morbidity is underappreciated. Present and future demand for PZQ treatment is bottlenecked, imbalanced and inequitable. Current dosing, treatment algorithms and access plans are suboptimal with treatment stalled during pregnancy. GROWING POINTS Raised dosing of PZQ (>40 mg/kg) is being explored in young children. Surveillance of female genital schistosomiasis FGS is increasing. Use of PZQ in pregnancy is safe and preventive chemotherapy guidelines are being revised in morbidity- and transmission-control settings. AREAS TIMELY FOR DEVELOPING RESEARCH Shifting focus of population-level control to individual-case management. Detection and prevention of FGS within general health services and integration of PZQ treatment for women and children in antenatal clinics. Feasibility studies assessing alternative and expanded access to PZQ treatment to at-risk children and mothers and pregnant women.
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Affiliation(s)
- Amaya L Bustinduy
- Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
| | - J Russell Stothard
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Jennifer F Friedman
- Center for International Health Research, Rhode Island Hospital, 55 Claverick Street, Suite 101, Providence, RI 02903, USA
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23
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Infurnari L, Galli L, Bigoloni A, Carbone A, Chiappetta S, Sala A, Ceserani N, Lazzarin A, Castagna A, Gaiera/ G. The use of circulating cathodic antigen rapid test and serology for diagnosis of active Schistosoma mansoni infection in migrants in Italy, a non-endemic country: a cross sectional study. Mem Inst Oswaldo Cruz 2017; 112:452-455. [PMID: 28591406 PMCID: PMC5446235 DOI: 10.1590/0074-02760160355] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Accepted: 03/04/2017] [Indexed: 12/23/2022] Open
Abstract
Diagnosis of schistosomiasis in migrants coming from endemic areas can be difficult, especially in asymptomatic subjects. Light-intensity disease, in fact, may be missed due to the low sensitivity of the stool microscopy and serologic testing cannot distinguish between a resolved infection and an active infection in patients who have been infected and treated in the past, because specific antibodies can persist despite cure. We describe a cross-sectional study conducted on 82 migrants tested for Schistosoma mansoni on single blood (anti-schistosome antibodies, total IgE) and urine [point-of-care (POC) circulating-cathodic-antigen (CCA) test] samples. A positive POC-CCA test (active infection) resulted in two untreated patients with a positive serology while all patients (n = 66) with a past infection showed a negative POC-CCA test. POC-CCA urine test in combination with serology may be helpful in rapidly differentiate active from past S. mansoni infection in migrants coming from endemic areas.
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Affiliation(s)
- Laura Infurnari
- San Raffaele Scientific Institute, Laboratory of Microbiology and Virology, Milan, Italy
| | - Laura Galli
- San Raffaele Scientific Institute, Infectious Diseases Department, Milan, Italy
| | - Alba Bigoloni
- San Raffaele Scientific Institute, Infectious Diseases Department, Milan, Italy
| | - Alessia Carbone
- San Raffaele Scientific Institute, Infectious Diseases Department, Milan, Italy
| | - Stefania Chiappetta
- San Raffaele Scientific Institute, Infectious Diseases Department, Milan, Italy
| | - Angelo Sala
- Saint Michel Centre, Society of Priests of the Sacred Heart of Betharram, Health Pastoral Diocese of Bouar, Bouar, Central African Republic
| | - Norberto Ceserani
- San Raffaele Scientific Institute, Infectious Diseases Department, Milan, Italy
| | - Adriano Lazzarin
- San Raffaele Scientific Institute, Infectious Diseases Department, Milan, Italy.,Università Vita-Salute San Raffaele, Milan, Italy
| | - Antonella Castagna
- San Raffaele Scientific Institute, Infectious Diseases Department, Milan, Italy.,Università Vita-Salute San Raffaele, Milan, Italy
| | - Giovanni Gaiera/
- San Raffaele Scientific Institute, Infectious Diseases Department, Milan, Italy
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24
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Won KY, Kanyi HM, Mwende FM, Wiegand RE, Goodhew EB, Priest JW, Lee YM, Njenga SM, Secor WE, Lammie PJ, Odiere MR. Multiplex Serologic Assessment of Schistosomiasis in Western Kenya: Antibody Responses in Preschool Aged Children as a Measure of Reduced Transmission. Am J Trop Med Hyg 2017; 96:1460-1467. [PMID: 28719280 PMCID: PMC5462587 DOI: 10.4269/ajtmh.16-0665] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Currently, impact of schistosomiasis control programs in Schistosoma mansoni–endemic areas is monitored primarily by assessment of parasitologic indicators only. Our study was conducted to evaluate the use of antibody responses as a way to measure the impact of schistosomiasis control programs. A total of 3,612 serum samples collected at three time points from children 1–5 years of age were tested for antibody responses to two schistosome antigens (soluble egg antigen [SEA] and Sm25) by multiplex bead assay. The overall prevalence of antibody responses to SEA was high at baseline (50.0%). After one round of mass drug administration (MDA), there was minimal change in odds of SEA positivity (odds ratio [OR] = 1.02, confidence interval [CI] = 0.79–1.32, P = 0.89). However, after two rounds of treatment, there was a slight decrease in odds of SEA positivity (OR = 0.80, CI = 0.63–1.02, P = 0.08). In contrast to the SEA results, prevalence of antibody responses to Sm25 was lowest at baseline (14.1%) and higher in years 2 (19.8%) and 3 (18.4%). After one round of MDA, odds of Sm25 positivity increased significantly (OR = 1.51, CI = 1.14–2.02, P = 0.005) and remained significantly higher than baseline after two rounds of MDA (OR = 1.37, CI = 1.07–1.76, P = 0.01). There was a significant decrease in the proportion of 1-year-olds with positive SEA responses from 33.1% in year 1 to 13.2% in year 3 and a corresponding decrease in the odds (OR = 3.25, CI = 1.75–6.08, P < 0.001). These results provide preliminary evidence that schistosomiasis program impact can be monitored using serologic responses.
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Affiliation(s)
- Kimberly Y Won
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Henry M Kanyi
- Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute, Nairobi, Kenya
| | - Faith M Mwende
- Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute, Nairobi, Kenya
| | - Ryan E Wiegand
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - E Brook Goodhew
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Jeffrey W Priest
- Division of Foodborne, Waterborne and Environmental Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Yeuk-Mui Lee
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Sammy M Njenga
- Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute, Nairobi, Kenya
| | - W Evan Secor
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Patrick J Lammie
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Maurice R Odiere
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
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25
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Arora N, Tripathi S, Singh AK, Mondal P, Mishra A, Prasad A. Micromanagement of Immune System: Role of miRNAs in Helminthic Infections. Front Microbiol 2017; 8:586. [PMID: 28450853 PMCID: PMC5390025 DOI: 10.3389/fmicb.2017.00586] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 03/21/2017] [Indexed: 01/09/2023] Open
Abstract
Helminthic infections fall under neglected tropical diseases, although they inflict severe morbidity to human and causes major economic burden on health care system in many developing countries. There is increased effort to understand their immunopathology in recent days due to their immuno-modulatory capabilities. Immune response is primarily controlled at the transcriptional level, however, microRNA-mediated RNA interference is emerging as important regulatory machinery that works at the translation level. In the past decade, microRNA (miRNA/miR) research has advanced with significant momentum. The result is ever increasing list of curated sequences from a broad panel of organisms including helminths. Several miRNAs had been discovered from trematodes, nematodes and cestodes like let-7, miR155, miR-199, miR-134, miR-223, miR-146, and fhe-mir-125a etc., with potential role in immune modulation. These miRs had been associated with TGF-β, MAPK, Toll-like receptor, PI3K/AKT signaling pathways and insulin growth factor regulation. Thus, controlling the immune cells development, survival, proliferation and death. Apart from micromanagement of immune system, they also express certain unique miRNA also like cis-miR-001, cis-miR-2, cis-miR-6, cis-miR-10, cis-miR-18, cis-miR-19, trs-mir-0001, fhe-miR-01, fhe-miR-07, fhe-miR-08, egr-miR-4988, egr-miR-4989 etc. The specific role played by most of these species specific unique miRs are yet to be discovered. However, these newly discovered miRNAs might serve as novel targets for therapeutic intervention or biomarkers for parasitic infections.
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Affiliation(s)
- Naina Arora
- School of Basic Sciences, Indian Institute of Technology MandiMandi, India
| | - Shweta Tripathi
- School of Basic Sciences, Indian Institute of Technology MandiMandi, India
| | - Aloukick K Singh
- Department of Immunology, Weizmann Institute of ScienceRehovot, Israel
| | - Prosenjit Mondal
- School of Basic Sciences, Indian Institute of Technology MandiMandi, India
| | - Amit Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology JodhpurJodhpur, India
| | - Amit Prasad
- School of Basic Sciences, Indian Institute of Technology MandiMandi, India
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Tchuem Tchuenté LA, Rollinson D, Stothard JR, Molyneux D. Moving from control to elimination of schistosomiasis in sub-Saharan Africa: time to change and adapt strategies. Infect Dis Poverty 2017; 6:42. [PMID: 28219412 PMCID: PMC5319063 DOI: 10.1186/s40249-017-0256-8] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Accepted: 02/08/2017] [Indexed: 11/17/2022] Open
Abstract
Schistosomiasis is a water borne parasitic disease of global importance and with ongoing control the disease endemic landscape is changing. In sub-Saharan Africa, for example, the landscape is becoming ever more heterogeneous as there are several species of Schistosoma that respond in different ways to ongoing preventive chemotherapy and the inter-sectoral interventions currently applied. The major focus of preventive chemotherapy is delivery of praziquantel by mass drug administration to those shown to be, or presumed to be, at-risk of infection and disease. In some countries, regional progress may be uneven but in certain locations there are very real prospects to transition from control into interruption of transmission, and ultimately elimination. To manage this transition requires reconsideration of some of the currently deployed diagnostic tools used in surveillance and downward realignment of existing prevalence thresholds to trigger mass treatment. A key challenge will be maintaining and if possible, expanding the current donation of praziquantel to currently overlooked groups, then judging when appropriate to move from mass drug administration to selective treatment. In so doing, this will ensure the health system is adapted, primed and shown to be cost-effective to respond to these changing disease dynamics as we move forward to 2020 targets and beyond.
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Affiliation(s)
- Louis-Albert Tchuem Tchuenté
- National Programme for the Control of Schistosomiasis and STH, Ministry of Public Health, Yaoundé, Cameroon. .,Centre for Schistosomiasis and Parasitology, University of Yaoundé I, Yaoundé, Cameroon.
| | - David Rollinson
- Department of Life Sciences, The Natural History Museum, London, SW7 5BD, UK
| | - J Russell Stothard
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - David Molyneux
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
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27
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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: 15] [Impact Index Per Article: 2.1] [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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Hinz R, Schwarz NG, Hahn A, Frickmann H. Serological approaches for the diagnosis of schistosomiasis - A review. Mol Cell Probes 2016; 31:2-21. [PMID: 27986555 DOI: 10.1016/j.mcp.2016.12.003] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 11/28/2016] [Accepted: 12/12/2016] [Indexed: 01/14/2023]
Abstract
Schistosomiasis is a common disease in endemic areas of Sub-Saharan Africa, South America and Asia. It is rare in Europe, mainly imported from endemic countries due to travelling or human migration. Available methods for the diagnosis of schistosomiasis comprise microscopic, molecular and serological approaches, with the latter detecting antigens or antibodies associated with Schistosoma spp. infection. The serological approach is a valuable screening tool in low-endemicity settings and for travel medicine, though the interpretation of any diagnostic results requires knowledge of test characteristics and a patient's history. Specific antibody detection by most currently used assays is only possible in a relatively late stage of infection and does not allow for the differentiation of acute from previous infections for therapeutic control or the discrimination between persisting infection and re-infection. Throughout the last decades, new target antigens have been identified, and assays with improved performance and suitability for use in the field have been developed. For numerous assays, large-scale studies are still required to reliably characterise assay characteristics alone and in association with other available methods for the diagnosis of schistosomiasis. Apart from S. mansoni, S. haematobium and S. japonicum, for which most available tests were developed, other species of Schistosoma that occur less frequently need to be taken into account. This narrative review describes and critically discusses the results of published studies on the evaluation of serological assays that detect antibodies against different Schistosoma species of humans. It provides insights into the diagnostic performance and an overview of available assays and their suitability for large-scale use or individual diagnosis, and thus sets the scene for serological diagnosis of schistosomiasis and the interpretation of results.
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Affiliation(s)
- Rebecca Hinz
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Germany; Department of Tropical Medicine at the Bernhard Nocht Institute, German Armed Forces Hospital Hamburg, Germany.
| | | | - Andreas Hahn
- Takeda Pharma Vertrieb GmbH & Co. KG, Berlin, Germany
| | - Hagen Frickmann
- Department of Tropical Medicine at the Bernhard Nocht Institute, German Armed Forces Hospital Hamburg, Germany; Institute for Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Germany
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29
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Comparative Assessment of Health Benefits of Praziquantel Treatment of Urogenital Schistosomiasis in Preschool and Primary School-Aged Children. BIOMED RESEARCH INTERNATIONAL 2016; 2016:9162631. [PMID: 27631011 PMCID: PMC5007301 DOI: 10.1155/2016/9162631] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 06/21/2016] [Accepted: 07/05/2016] [Indexed: 12/15/2022]
Abstract
Schistosomiasis is a major public health problem in Africa. However, it is only recently that its burden has become recognised as a significant component impacting on the health and development of preschool-aged children. A longitudinal study was conducted in Zimbabwean children to determine the effect of single praziquantel treatment on Schistosoma haematobium-related morbidity markers: microhaematuria, proteinuria, and albuminuria. Changes in these indicators were compared in 1-5 years versus 6-10 years age groups to determine if treatment outcomes differed by age. Praziquantel was efficacious at reducing infection 12 weeks after treatment: cure rate = 94.6% (95% CI: 87.9-97.7%). Infection rates remained lower at 12 months after treatment compared to baseline in both age groups. Among treated children, the odds of morbidity at 12 weeks were significantly lower compared to baseline for proteinuria: odds ratio (OR) = 0.54 (95% CI: 0.31-0.95) and albuminuria: OR = 0.05 (95% CI: 0.02-0.14). Microhaematuria significantly reduced 12 months after treatment, and the effect of treatment did not differ by age group: OR = 0.97 (95% CI: 0.50-1.87). In conclusion, praziquantel treatment has health benefits in preschool-aged children exposed to S. haematobium and its efficacy on infection and morbidity is not age-dependent.
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Casacuberta M, Kinunghi S, Vennervald BJ, Olsen A. Evaluation and optimization of the Circulating Cathodic Antigen (POC-CCA) cassette test for detecting Schistosoma mansoni infection by using image analysis in school children in Mwanza Region, Tanzania. Parasite Epidemiol Control 2016; 1:105-115. [PMID: 27430027 PMCID: PMC4946158 DOI: 10.1016/j.parepi.2016.04.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 04/12/2016] [Accepted: 04/13/2016] [Indexed: 12/11/2022] Open
Abstract
There is a need for diagnostic techniques which are sensitive, specific, rapid and easy to perform at the point-of-care. The aim of this study was to evaluate the diagnostic performance of the Circulating Cathodic Antigen (POC-CCA) assay for Schistosoma mansoni in four schools along the coast of Lake Victoria in Mwanza Region, Tanzania, and to optimize the reading of the POC-CCA test lines by using a computer software image analysis. Initially, a pilot study in 106 school children indicated that time of urine collection did not have an impact on CCA results as 84.9% (90) had identical scores from a urine collected in the morning and a urine taken at midday after drinking 0.5 L of water. The main study was conducted among 404 school children (aged 9–12 years) where stool and urine samples were collected for three consecutive days. For S. mansoni diagnosis, stool samples were examined for eggs with duplicate Kato-Katz smears, whereas urine samples were tested for presence of antigen by POC-CCA. The proportion of positive individuals for S. mansoni by one POC-CCA was higher compared to two Kato-Katz smears (66.1% vs. 28.7%; p < 0.0001). Both proportions increased expectedly when three POC-CCAs were compared to six Kato-Katz smears (75.0% vs. 42.6%; p < 0.0001). Three POC-CCAs were more sensitive (94.7%) than six Kato-Katz smears (53.8%) using the combined results of three POC-CCAs and six Kato-Katz smears as the ‘gold standard’. To optimize the reading of the POC-CCA, a Software tool (Image Studio Lite®) was used to read and quantify the colour (expressed as pixels) of the test line on all positive tests, showing a positive correlation between number of pixels and the visually scored intensities and between number of pixels and egg counts. In conclusion, the POC-CCA assay seems to be a more appropriate tool for S. mansoni diagnosis compared to the Kato-Katz method in endemic communities such as Mwanza Region. Optimization of the tool in terms of cassette-reading could be assessed by computer software which was able to quantify the colour of the lines in the strip of the cassette.
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Affiliation(s)
- Miriam Casacuberta
- Parasitology and Aquatic Diseases, Department of Veterinary Disease Biology, University of Copenhagen, Dyrlaegevej 100, DK-1870 Frederiksberg C, Denmark
| | - Safari Kinunghi
- National Institute for Medical Research (NIMR), Mwanza Research Centre, Mwanza, Tanzania)
| | - Birgitte J Vennervald
- Parasitology and Aquatic Diseases, Department of Veterinary Disease Biology, University of Copenhagen, Dyrlaegevej 100, DK-1870 Frederiksberg C, Denmark
| | - Annette Olsen
- Parasitology and Aquatic Diseases, Department of Veterinary Disease Biology, University of Copenhagen, Dyrlaegevej 100, DK-1870 Frederiksberg C, Denmark
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Kittur N, Castleman JD, Campbell CH, King CH, Colley DG. Comparison of Schistosoma mansoni Prevalence and Intensity of Infection, as Determined by the Circulating Cathodic Antigen Urine Assay or by the Kato-Katz Fecal Assay: A Systematic Review. Am J Trop Med Hyg 2016; 94:605-610. [PMID: 26755565 PMCID: PMC4775897 DOI: 10.4269/ajtmh.15-0725] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 11/11/2015] [Indexed: 12/18/2022] Open
Abstract
The relationship between results from Kato-Katz (KK) fecal microscopy and urine-based point-of-care circulating cathodic antigen (POC-CCA) assays for Schistosoma mansoni infection remains a critical issue. This systematic literature review of 25 published papers compares prevalence of S. mansoni infection by KK with that by the POC-CCA assay. Nineteen published studies met our inclusion criteria for data extraction and analysis. Above a prevalence of 50% by KK, KK and POC-CCA results yielded essentially the same prevalence. Below 50% prevalence by KK, the prevalence by the POC-CCA assay was between 1.5- and 6-fold higher and increased as prevalence by KK decreased. Five of nine publications met inclusion criteria for extractable data on intensity of S. mansoni infection by KK assay and visual band density using the POC-CCA assay. A clear positive relationship exists between intensity by the KK and POC-CCA assays. This systematic review indicates that below 50% prevalence, the POC-CCA assay is much more sensitive than the KK assay. However, the existing data are inadequate to precisely define the relationship between POC-CCA and KK at lower levels of KK prevalence. More studies directly comparing the two assays in low-prevalence areas are essential to inform decision-making by national schistosomiasis control programs.
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Affiliation(s)
| | | | | | | | - Daniel G. Colley
- *Address correspondence to Daniel G. Colley, Center for Tropical and Emerging Global Diseases, Room 330B Coverdell Center, 500 DW Brooks Drive, Athens, GA 30602. E-mail:
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Evaluation of the CCA Immuno-Chromatographic Test to Diagnose Schistosoma mansoni in Minas Gerais State, Brazil. PLoS Negl Trop Dis 2016; 10:e0004357. [PMID: 26752073 PMCID: PMC4709075 DOI: 10.1371/journal.pntd.0004357] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 12/14/2015] [Indexed: 12/21/2022] Open
Abstract
Background The Kato-Katz (KK) stool smear is the standard test for the diagnosis of Schistosoma mansoni infection, but suffers from low sensitivity when infections intensities are moderate to low. Thus, misdiagnosed individuals remain untreated and contribute to the disease transmission, thereby forestalling public health efforts to move from a modality of disease control to one of elimination. As an alternative, the urine-based diagnosis of schistosomiasis mansoni via the circulating cathodic antigen immuno-chromatographic test (CCA-ICT) has been extensively evaluated in Africa with the conclusion that it may replace the KK test in areas where prevalences are moderate or high. Methods and Findings The objective was to measure the performance of the CCA-ICT in a sample study population composed of residents from non-endemic and endemic areas for schistosomiasis mansoni in two municipalities of Minas Gerais state, Brazil. Volunteers (130) were classified into three infection status groups based on duplicate Kato-Katz thick smears from one stool sample (2KK test): 41 negative individuals from non-endemic areas, 41 negative individuals from endemic areas and 48 infected individuals from endemic areas. Infection status was also determined by the CCA-ICT and infection exposure by antibody ELISA (enzyme-linked immunosorbent assay) to S. mansoni soluble egg antigen (SEA) and soluble (adult) worm antigen preparation (SWAP). Sensitivity and specificity were influenced by whether the trace score visually adjudicated in the CCA-ICT was characterized as positive or negative for S. mansoni infection. An analysis of a two-graph receiver operating characteristic was performed to change the cutoff point. When the trace score was interpreted as a positive rather than as a negative result, the specificity decreased from 97.6% to 78.0% whereas sensitivity increased from 68.7% to 85.4%. A significantly positive correlation between the CCA-ICT scores and egg counts was identified (r = 0.6252, p = 0.0001). However, the CCA-ICT misdiagnosed as negative 14.6% of 2KK positive individuals, predominantly those with light infections (fewer than 100 eggs/g feces). Considering 2KK as reference test, the discriminating power of the CCA-ICT (the area under the curve [AUC] = 0.817) was greater than the SEA-ELISA (AUC = 0.744) and SWAP-ELISA (AUC = 0.704). Conclusion Our data for the performance of the CCA-ICT in the Brazilian communities endemic for schistosomiasis mansoni support those from Africa, i.e., in areas with greater infection prevalence and intensities, the CCA-ICT may be useful as a tool to indicate community-based preventative chemotherapy without individual diagnosis. However, because of the Brazilian Ministry of Health’s recommendation for individual diagnosis in areas where prevalence is less than 15%, i.e., those areas in which infection intensities are likely to be lowest, the CCA-ICT lacks the sensitivity to be used as standalone diagnostic tool. Detecting parasite eggs in stool by the Kato-Katz (KK) stool smear is the standard diagnostic test for infection with the flatworm parasite, Schistosoma mansoni. However, the test can miss those who have low burdens of infection, i.e., with few eggs in their feces. These misdiagnosed individuals, therefore, do not receive drug treatment and can continue to transmit the parasite into the environment putting the community at risk of infection. As an alternative diagnostic approach, the circulating cathodic antigen immuno-chromatographic test (CCA-ICT) is a simple-to-use handheld device (similar to a pregnancy test) that only needs urine to provide a quick and visual indication of whether one is infected or not. The consensus from studies in Africa is that the CCA-ICT could replace the KK test in those areas where people are more likely to harbor moderate to high worm burdens (i.e., more eggs in stool), but, like the KK test, it can miss those harboring light infection intensities. We evaluated the CCA-ICT performance in urine samples from 130 individuals living in areas non-endemic and endemic for schistosomiasis mansoni within the municipalities of Governador Valadares and Manhuaçu, Minas Gerais state, Brazil. The CCA-ICT performance characteristics, chiefly, sensitivity and specificity, depended on whether a ‘trace’ visual reading of the test was considered as a positive or negative diagnosis. We noted a positive correlation between the CCA-ICT scores and egg counts. However, the CCA-ICT misdiagnosed as negative about 15% of KK positive individuals, predominantly those with light infections. The CCA-ICT, nonetheless, had better discriminating power than commonly used antibody-based tests. We conclude that the CCA-ICT offers reasonable performance to diagnosis S. mansoni infection. However, in areas where infections intensities are light, the test lacks the sensitivity to be used as standalone diagnostic tool.
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Hosking CG, McWilliam HEG, Driguez P, Piedrafita D, Li Y, McManus DP, Ilag LL, Meeusen ENT, de Veer MJ. Generation of a Novel Bacteriophage Library Displaying scFv Antibody Fragments from the Natural Buffalo Host to Identify Antigens from Adult Schistosoma japonicum for Diagnostic Development. PLoS Negl Trop Dis 2015; 9:e0004280. [PMID: 26684756 PMCID: PMC4686158 DOI: 10.1371/journal.pntd.0004280] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 11/13/2015] [Indexed: 12/27/2022] Open
Abstract
The development of effective diagnostic tools will be essential in the continuing fight to reduce schistosome infection; however, the diagnostic tests available to date are generally laborious and difficult to implement in current parasite control strategies. We generated a series of single-chain antibody Fv domain (scFv) phage display libraries from the portal lymph node of field exposed water buffaloes, Bubalus bubalis, 11–12 days post challenge with Schistosoma japonicum cercariae. The selected scFv-phages showed clear enrichment towards adult schistosomes and excretory-secretory (ES) proteins by immunofluorescence, ELISA and western blot analysis. The enriched libraries were used to probe a schistosome specific protein microarray resulting in the recognition of a number of proteins, five of which were specific to schistosomes, with RNA expression predominantly in the adult life-stage based on interrogation of schistosome expressed sequence tags (EST). As the libraries were enriched by panning against ES products, these antigens may be excreted or secreted into the host vasculature and hence may make good targets for a diagnostic assay. Further selection of the scFv library against infected mouse sera identified five soluble scFv clones that could selectively recognise soluble whole adult preparations (SWAP) relative to an irrelevant protein control (ovalbumin). Furthermore, two of the identified scFv clones also selectively recognised SWAP proteins when spiked into naïve mouse sera. These host B-cell derived scFvs that specifically bind to schistosome protein preparations will be valuable reagents for further development of a cost effective point-of-care diagnostic test. Mass drug administration using the highly effective drug praziquantel (PZQ) is currently the method of choice to combat schistosomiasis. However, this treatment regime has limitations; in particular, it does not prevent re-infection and sporadic parasite resistance against PZQ is a continuing threat. The path to the successful control of schistosomiasis is highly challenging and must consider, not only the complex nature of the host-parasite interaction, but also the capacity to assess disease burden and parasite re-emergence in communities where successful control has been achieved. Furthermore, control programs must be economically sustainable in endemic countries and despite significant recent advancements the elimination of schistosomiasis may still be some time away. Accordingly, there is a definitive need to formulate innovative approaches for the development of improved diagnostic tools to accurately assess the disease burden associated with active schistosome infections. Here we describe the usefulness of a phage display library to mature antibody fragments derived from lymph node RNA of the natural buffalo host of the Asian schistosome, Schistosoma japonicum, following an experimental infection. These mature antibody fragments were able to bind native parasite proteins and could thus be used to develop a low cost and accurate point-of-care diagnostic test.
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Affiliation(s)
| | - Hamish E. G. McWilliam
- Department of Microbiology and Immunology, The University of Melbourne, the Peter Doherty Institute for Infection and Immunity, Parkville, Victoria, Australia
| | - Patrick Driguez
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - David Piedrafita
- School of Applied Sciences and Engineering, Federation University, Churchill, Victoria, Australia
| | - Yuesheng Li
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Donald P. McManus
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Leodevico L. Ilag
- Bio21 Molecular Sciences and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Els N. T. Meeusen
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Michael J. de Veer
- Department of Physiology, Monash University, Clayton, Victoria, Australia
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Downs JA, Corstjens PLAM, Mngara J, Lutonja P, Isingo R, Urassa M, Kornelis D, van Dam GJ. Correlation of serum and dried blood spot results for quantitation of Schistosoma circulating anodic antigen: a proof of principle. Acta Trop 2015; 150:59-63. [PMID: 26149541 DOI: 10.1016/j.actatropica.2015.06.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 06/15/2015] [Accepted: 06/28/2015] [Indexed: 11/18/2022]
Abstract
Circulating anodic antigen (CAA) testing is a powerful, increasingly-used tool for diagnosis of active schistosome infection. We sought to determine the feasibility and reliability of measuring CAA in blood spots collected on Whatman 903 protein saver cards, which are the predominant filter papers used worldwide for dried blood spot (DBS) research and clinical care. CAA was eluted from blood spots collected from 19 individuals onto Whatman 903 cards in Mwanza, Tanzania, and the assay was optimized to achieve CAA ratios comparable to those obtained from the spots' corresponding serum samples. The optimized assay was then used to determine the correlation of serum samples (n=16) with DBS from cards that had been stored for 8 years at ambient temperature. Using a DBS volume equivalent to approximately four times the quantity of serum, CAA testing in DBS had a sensitivity of 76% and a specificity of 79% compared to CAA testing in serum. CAA testing was reliable in samples eluted from Whatman 903 cards that had been stored for 8 years at ambient temperature. The overall kappa coefficient was 0.53 (standard error 0.17, p<0.001). We conclude that CAA can be reliably and accurately measured in DBS collected onto the filter paper that is most commonly used for clinical care and research, and that can be stored from prolonged periods of time. This finding opens new avenues for future work among more than 700million individuals living in areas worldwide in which schistosomes are endemic.
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Affiliation(s)
- Jennifer A Downs
- Center for Global Health, Weill Cornell Medical College, 402 E. 67th Street, Second Floor, New York, NY, USA; Department of Medicine, Bugando Medical Centre, Box 1370, Mwanza, Tanzania.
| | - Paul L A M Corstjens
- Department of Molecular Cell Biology, Leiden University Medical Center, Postzone S1-P, Postbus 9600, 2300 RC Leiden, The Netherlands.
| | - Julius Mngara
- National Institute for Medical Research-Mwanza Research Centre, Box 1462, Mwanza, Tanzania.
| | - Peter Lutonja
- National Institute for Medical Research-Mwanza Research Centre, Box 1462, Mwanza, Tanzania.
| | - Raphael Isingo
- National Institute for Medical Research-Mwanza Research Centre, Box 1462, Mwanza, Tanzania.
| | - Mark Urassa
- National Institute for Medical Research-Mwanza Research Centre, Box 1462, Mwanza, Tanzania.
| | - Dieuwke Kornelis
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands.
| | - Govert J van Dam
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands.
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Utzinger J, Becker SL, van Lieshout L, van Dam GJ, Knopp S. New diagnostic tools in schistosomiasis. Clin Microbiol Infect 2015; 21:529-42. [PMID: 25843503 DOI: 10.1016/j.cmi.2015.03.014] [Citation(s) in RCA: 181] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 03/21/2015] [Accepted: 03/21/2015] [Indexed: 12/22/2022]
Abstract
Schistosomiasis is a water-based parasitic disease that affects over 250 million people. Control efforts have long been in vain, which is one reason why schistosomiasis is considered a neglected tropical disease. However, since the new millennium, interventions against schistosomiasis are escalating. The initial impetus stems from a 2001 World Health Assembly resolution, urging member states to scale-up deworming of school-aged children with the anthelminthic drug praziquantel. Because praziquantel is safe, efficacious and inexpensive when delivered through the school platform, diagnosis before drug intervention was deemed unnecessary and not cost-effective. Hence, there was little interest in research and development of novel diagnostic tools. With the recent publication of the World Health Organization (WHO) Roadmap to overcome the impact of neglected tropical diseases in 2020, we have entered a new era. Elimination of schistosomiasis has become the buzzword and this has important ramifications for diagnostic tools. Indeed, measuring progress towards the WHO Roadmap and whether local elimination has been achieved requires highly accurate diagnostic assays. Here, we introduce target product profiles for diagnostic tools that are required for different stages of a schistosomiasis control programme. We provide an update of the latest developments in schistosomiasis diagnosis, including microscopic techniques, rapid diagnostic tests for antigen detection, polymerase chain reaction (PCR) assays and proxy markers for morbidity assessments. Particular emphasis is placed on challenges and solutions for new technologies to enter clinical practice.
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Affiliation(s)
- J Utzinger
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.
| | - S L Becker
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Institute of Medical Microbiology and Hygiene, Saarland University Medical Centre, Homburg/Saar, Germany
| | - L van Lieshout
- Department of Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
| | - G J van Dam
- Department of Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
| | - S Knopp
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Department of Life Sciences, Natural History Museum, London, UK
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Ochodo EA, Gopalakrishna G, Spek B, Reitsma JB, van Lieshout L, Polman K, Lamberton P, Bossuyt PMM, Leeflang MMG. Circulating antigen tests and urine reagent strips for diagnosis of active schistosomiasis in endemic areas. Cochrane Database Syst Rev 2015; 2015:CD009579. [PMID: 25758180 PMCID: PMC4455231 DOI: 10.1002/14651858.cd009579.pub2] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Point-of-care (POC) tests for diagnosing schistosomiasis include tests based on circulating antigen detection and urine reagent strip tests. If they had sufficient diagnostic accuracy they could replace conventional microscopy as they provide a quicker answer and are easier to use. OBJECTIVES To summarise the diagnostic accuracy of: a) urine reagent strip tests in detecting active Schistosoma haematobium infection, with microscopy as the reference standard; and b) circulating antigen tests for detecting active Schistosoma infection in geographical regions endemic for Schistosoma mansoni or S. haematobium or both, with microscopy as the reference standard. SEARCH METHODS We searched the electronic databases MEDLINE, EMBASE, BIOSIS, MEDION, and Health Technology Assessment (HTA) without language restriction up to 30 June 2014. SELECTION CRITERIA We included studies that used microscopy as the reference standard: for S. haematobium, microscopy of urine prepared by filtration, centrifugation, or sedimentation methods; and for S. mansoni, microscopy of stool by Kato-Katz thick smear. We included studies on participants residing in endemic areas only. DATA COLLECTION AND ANALYSIS Two review authors independently extracted data, assessed quality of the data using QUADAS-2, and performed meta-analysis where appropriate. Using the variability of test thresholds, we used the hierarchical summary receiver operating characteristic (HSROC) model for all eligible tests (except the circulating cathodic antigen (CCA) POC for S. mansoni, where the bivariate random-effects model was more appropriate). We investigated heterogeneity, and carried out indirect comparisons where data were sufficient. Results for sensitivity and specificity are presented as percentages with 95% confidence intervals (CI). MAIN RESULTS We included 90 studies; 88 from field settings in Africa. The median S. haematobium infection prevalence was 41% (range 1% to 89%) and 36% for S. mansoni (range 8% to 95%). Study design and conduct were poorly reported against current standards. Tests for S. haematobium Urine reagent test strips versus microscopyCompared to microscopy, the detection of microhaematuria on test strips had the highest sensitivity and specificity (sensitivity 75%, 95% CI 71% to 79%; specificity 87%, 95% CI 84% to 90%; 74 studies, 102,447 participants). For proteinuria, sensitivity was 61% and specificity was 82% (82,113 participants); and for leukocyturia, sensitivity was 58% and specificity 61% (1532 participants). However, the difference in overall test accuracy between the urine reagent strips for microhaematuria and proteinuria was not found to be different when we compared separate populations (P = 0.25), or when direct comparisons within the same individuals were performed (paired studies; P = 0.21).When tests were evaluated against the higher quality reference standard (when multiple samples were analysed), sensitivity was marginally lower for microhaematuria (71% vs 75%) and for proteinuria (49% vs 61%). The specificity of these tests was comparable. Antigen assayCompared to microscopy, the CCA test showed considerable heterogeneity; meta-analytic sensitivity estimate was 39%, 95% CI 6% to 73%; specificity 78%, 95% CI 55% to 100% (four studies, 901 participants). Tests for S. mansoni Compared to microscopy, the CCA test meta-analytic estimates for detecting S. mansoni at a single threshold of trace positive were: sensitivity 89% (95% CI 86% to 92%); and specificity 55% (95% CI 46% to 65%; 15 studies, 6091 participants) Against a higher quality reference standard, the sensitivity results were comparable (89% vs 88%) but specificity was higher (66% vs 55%). For the CAA test, sensitivity ranged from 47% to 94%, and specificity from 8% to 100% (4 studies, 1583 participants). AUTHORS' CONCLUSIONS Among the evaluated tests for S. haematobium infection, microhaematuria correctly detected the largest proportions of infections and non-infections identified by microscopy.The CCA POC test for S. mansoni detects a very large proportion of infections identified by microscopy, but it misclassifies a large proportion of microscopy negatives as positives in endemic areas with a moderate to high prevalence of infection, possibly because the test is potentially more sensitive than microscopy.
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Affiliation(s)
- Eleanor A Ochodo
- Academic Medical Center, University of AmsterdamDepartment of Clinical Epidemiology, Biostatistics and BioinformaticsAmsterdamNetherlands1100 DD
- Stellenbosch UniversityCentre for Evidence‐based Health Care, Faculty of Medicine and Health SciencesCape TownSouth Africa
| | - Gowri Gopalakrishna
- Academic Medical Center, University of AmsterdamDepartment of Clinical Epidemiology, Biostatistics and BioinformaticsAmsterdamNetherlands1100 DD
| | - Bea Spek
- Academic Medical Center, University of AmsterdamDepartment of Clinical Epidemiology, Biostatistics and BioinformaticsAmsterdamNetherlands1100 DD
- Hanze University GroningenDepartment of Speech and Language PathologyEyssoniuspleinGroningenNetherlands
| | - Johannes B Reitsma
- University Medical Center UtrechtJulius Center for Health Sciences and Primary CarePO Box 85500UtrechtNetherlands3508 GA Utrecht
| | - Lisette van Lieshout
- Leiden University Medical CenterDepartment of ParasitologyPO Box 9600LeidenNetherlands2300 RC
| | - Katja Polman
- Institute of Tropical MedicineDepartment of Biomedical SciencesNationalestraat 155AntwerpBelgium2000
| | - Poppy Lamberton
- Imperial College LondonDepartment of Infectious Disease EpidemiologySt. Mary's Campus, Norfolk PlaceLondonUKW2 1PG
| | - Patrick MM Bossuyt
- Academic Medical Center, University of AmsterdamDepartment of Clinical Epidemiology, Biostatistics and BioinformaticsAmsterdamNetherlands1100 DD
| | - Mariska MG Leeflang
- Academic Medical Center, University of AmsterdamDepartment of Clinical Epidemiology, Biostatistics and BioinformaticsAmsterdamNetherlands1100 DD
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Abstract
Schistosomiasis is a chronic disease that affects ∼200 million people. The extended health impact of the disease has been estimated to exceed that of malaria or tuberculosis and to be nearer to that of HIV/AIDS. Within endemic areas, children carry the heaviest burden of infection. Infection/disease is controlled by the treatment of infected subjects with the anthelminthic drug praziquantel. Global initiatives from Partners of Parasite Control, including the World Health Organization (WHO), advocate regular school-based deworming strategies to reduce the development of severe morbidity, promote school-child health and development, and improve the cognitive potential of children. Until recently, preschool-aged children were excluded from schistosome treatment, creating a health inequity in affected populations. In 2010, the WHO updated their recommendations for the treatment of schistosomiasis in preschool-aged children (ie, children aged ≤5 years). This change was the culmination of several decades of research on schistosome epidemiology, immunology, and pathology in this age group. The recent development of a pediatric formulation of praziquantel (soon to enter clinical trials) should advance control efforts in preschool-aged children, with the goal of including these children in preventative chemotherapy (as currently occurs for soil-transmitted helminths). This review discusses the research work supporting the WHO revision of recommendations for treating preschool-aged children, as well as current barriers and knowledge gaps in pediatric schistosomiasis control.
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Affiliation(s)
- Francisca Mutapi
- Institute of Immunology and Infection Research, Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
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Nalugwa A, Olsen A, Tukahebwa M, Nuwaha F. Intestinal schistosomiasis among preschool children along the shores of Lake Victoria in Uganda. Acta Trop 2015; 142:115-21. [PMID: 25454166 DOI: 10.1016/j.actatropica.2014.11.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Revised: 11/13/2014] [Accepted: 11/21/2014] [Indexed: 12/20/2022]
Abstract
Schistosomiasis, a disease caused by Schistosoma trematode parasites, affects hundreds of millions of people and accounts for more than 40% of the global health burden due to neglected tropical diseases. In Uganda, intestinal schistosomiasis is endemic in 73 out of 112 districts and about 55% of the population of 36 million individuals are at risk. There is scanty information on the status and burden of schistosomiasis in preschool children less than six years of age in Uganda. This study aimed to assess the status of Schistosoma mansoni infections in children aged 1-5 years in Uganda. S. mansoni prevalence and intensity of infection were examined in 3058 children from 5 districts along Lake Victoria shoreline, eastern Uganda. For each child one stool sample was collected on three consecutive days. The Kato-Katz technique was used to prepare stool smears on slides for microscopic examination. Short interviews with a standardized pre-tested questionnaire prepared in the local language (Lusoga) were administered to each caregiver to identify risk factors associated with S. mansoni infection. An overall S. mansoni prevalence of 39.3% (95% CI: 38.0-41.1%) was estimated out of the 3058 stool samples examined. The geometric mean intensity of S. mansoni among the infected children was 273 (95% CI: 241-305) eggs per gram of faeces. Both prevalence and intensity of infection increased linearly with age (P<0.0001) and were highest in the age group 49-60 months. Majority (61%) of the children, especially in the age group 12-24 months (84.2%; 95% CI: 75.6-90.1%), were lightly infected. Short interviews with caregivers revealed that preschool children, 1-5 years old, get exposed to S. mansoni infested waters through bathing, playing or swimming. It is important that the Uganda national control programme for schistosomiasis takes preschool children into consideration and that health education on transmission of schistosomiasis is delivered to the endemic communities regularly.
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Carneiro TR, Peralta RHS, Pinheiro MCC, Oliveira SMD, Peralta JM, Bezerra FSM. A conventional polymerase chain reaction-based method for the diagnosis of human schistosomiasis in stool samples from individuals in a low-endemicity area. Mem Inst Oswaldo Cruz 2015; 108:1037-44. [PMID: 24402156 PMCID: PMC4005555 DOI: 10.1590/0074-0276130202] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 10/07/2013] [Indexed: 01/17/2023] Open
Abstract
The aim of this study was to evaluate the efficacy of a polymerase chain reaction
(PCR)-based method to detect Schistosoma mansoni DNA in stool
samples from individuals living in a low-endemicity area in Brazil. Of the 125
initial stool samples, 80 were ELISA reactive and eggs were identified in 19 of the
samples by parasitological examination. For the PCR evaluations, 56 stool samples
were selected and divided into five groups. Groups I-IV were scored negative for
S. mansoni eggs by parasitological examination. Groups I and II
were ELISA reactive, whereas Groups III and IV were ELISA nonreactive. Groups II and
III were positive for other intestinal parasites. PCR testing scored eight samples as
positive from these four groups. Group V represented the S. mansoni
-positive group and it included ELISA-reactive samples that were scored positive for
S. mansoni by one or more parasitological examinations (6/19 were
positive by Kato-Katz method, 9/17 by saline gradient and 10/13 by Helmintex®). PCR
scored 13 of these 19 samples as positive for S. mansoni . We
conclude that while none of these methods yielded 100% sensitivity, a combination of
techniques should be effective for improving the detection of S.
mansoni infection in low-endemicity areas.
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Affiliation(s)
| | | | | | | | - José Mauro Peralta
- Departamento de Imunologia, Instituto de Microbiologia Paulo de Goes, Universidade Federal do Rio de Janeiro, Brasil, Rio de JaneiroRJ
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van Dam GJ, Xu J, Bergquist R, de Dood CJ, Utzinger J, Qin ZQ, Guan W, Feng T, Yu XL, Zhou J, Zheng M, Zhou XN, Corstjens PL. An ultra-sensitive assay targeting the circulating anodic antigen for the diagnosis of Schistosoma japonicum in a low-endemic area, People's Republic of China. Acta Trop 2015; 141:190-7. [PMID: 25128703 DOI: 10.1016/j.actatropica.2014.08.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 07/28/2014] [Accepted: 08/05/2014] [Indexed: 12/31/2022]
Abstract
The downward trend in prevalence and intensity of Schistosoma japonicum infection in the People's Republic of China (P.R. China) has reached a level where accurate methods are required for monitoring the national schistosomiasis control programme and to verify whether transmission has been interrupted. We have assessed the prevalence of active S. japonicum infection by use of an up-converting phosphor lateral-flow (UCP-LF) assay for determination of circulating anodic antigens (CAA) in urine and serum, and compared the findings with those of the Kato-Katz technique for egg detection in stool and an immunohaemagglutination assay (IHA) for specific antibodies in serum. The study was carried out in three villages located in a remaining S. japonicum-endemic area in P.R. China. Overall, 423 individuals were investigated by Kato-Katz, 395 by IHA, 371 with the UCP-LF CAA assay adapted for urine and 178 with the UCP-LF CAA assay applied on serum. The IHA showed the highest number of positive results (n=107, 27.1%). The UCP-LF CAA urine assay detected 36 CAA positives (9.7%) and the serum-based CAA assay 21 positives (11.8%). The Kato-Katz technique revealed only six positive stool samples (1.4%). Among those 166 individuals with complete data records, sensitivities of the different assays were determined versus a combined 'gold' standard, showing the highest sensitivity for the urine CAA assay (93%), followed by the serum CAA (73%) and IHA (53%), whilst triplicate Kato-Katz thick smears had a very low sensitivity (13%). Serum CAA concentrations were about 10-fold higher than in urine and were significantly correlated. Highest prevalences as determined by CAA were found in older age groups (>40 years). Half of the CAA- or egg-positive cases were negative for antibodies by IHA, thereby revealing an important obstacle for the effectiveness of the current schistosomiasis control and elimination efforts. The significantly higher prevalence of active schistosome infections as shown by the urine and serum UCP-LF CAA assays has implications for the national control and elimination programme in P.R. China, particularly in respect to case-finding and intervention strategies.
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Fernández-Soto P, Gandasegui Arahuetes J, Sánchez Hernández A, López Abán J, Vicente Santiago B, Muro A. A loop-mediated isothermal amplification (LAMP) assay for early detection of Schistosoma mansoni in stool samples: a diagnostic approach in a murine model. PLoS Negl Trop Dis 2014; 8:e3126. [PMID: 25187956 PMCID: PMC4154662 DOI: 10.1371/journal.pntd.0003126] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 07/18/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Human schistosomiasis, mainly due to Schistosoma mansoni species, is one of the most prevalent parasitic diseases worldwide. To overcome the drawbacks of classical parasitological and serological methods in detecting S. mansoni infections, especially in acute stage of the disease, development of cost-effective, simple and rapid molecular methods is still needed for the diagnosis of schistosomiasis. A promising approach is the loop-mediated isothermal amplification (LAMP) technology. Compared to PCR-based assays, LAMP has the advantages of reaction simplicity, rapidity, specificity, cost-effectiveness and higher amplification efficiency. Additionally, as results can be inspected by the naked eye, the technique has great potential for use in low-income countries. METHODOLOGY/PRINCIPAL FINDINGS A sequence corresponding to a mitochondrial S. mansoni minisatellite DNA region was selected as a target for designing a LAMP-based method to detect S. mansoni DNA in stool samples. We used a S. mansoni murine model to obtain well defined stool and sera samples from infected mice with S. mansoni cercariae. Samples were taken weekly from week 0 to 8 post-infection and the Kato-Katz and ELISA techniques were used for monitoring the infection. Primer set designed were tested using a commercial reaction mixture for LAMP assay and an in house mixture to compare results. Specificity of LAMP was tested using 16 DNA samples from different parasites, including several Schistosoma species, and no cross-reactions were found. The detection limit of our LAMP assay (SmMIT-LAMP) was 1 fg of S. mansoni DNA. When testing stool samples from infected mice the SmMIT-LAMP detected S. mansoni DNA as soon as 1 week post-infection. CONCLUSIONS/SIGNIFICANCE We have developed, for the first time, a cost-effective, easy to perform, specific and sensitive LAMP assay for early detection of S. mansoni in stool samples. The method is potentially and readily adaptable for field diagnosis and disease surveillance in schistosomiasis-endemic areas.
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Affiliation(s)
- Pedro Fernández-Soto
- IBSAL-CIETUS (Instituto de Investigación Biomédica de Salamanca-Centro de Investigación de Enfermedades Tropicales de la Universidad de Salamanca), Facultad de Farmacia, Universidad de Salamanca, Salamanca, Spain
- * E-mail:
| | - Javier Gandasegui Arahuetes
- IBSAL-CIETUS (Instituto de Investigación Biomédica de Salamanca-Centro de Investigación de Enfermedades Tropicales de la Universidad de Salamanca), Facultad de Farmacia, Universidad de Salamanca, Salamanca, Spain
| | - Alicia Sánchez Hernández
- IBSAL-CIETUS (Instituto de Investigación Biomédica de Salamanca-Centro de Investigación de Enfermedades Tropicales de la Universidad de Salamanca), Facultad de Farmacia, Universidad de Salamanca, Salamanca, Spain
| | - Julio López Abán
- IBSAL-CIETUS (Instituto de Investigación Biomédica de Salamanca-Centro de Investigación de Enfermedades Tropicales de la Universidad de Salamanca), Facultad de Farmacia, Universidad de Salamanca, Salamanca, Spain
| | - Belén Vicente Santiago
- IBSAL-CIETUS (Instituto de Investigación Biomédica de Salamanca-Centro de Investigación de Enfermedades Tropicales de la Universidad de Salamanca), Facultad de Farmacia, Universidad de Salamanca, Salamanca, Spain
| | - Antonio Muro
- IBSAL-CIETUS (Instituto de Investigación Biomédica de Salamanca-Centro de Investigación de Enfermedades Tropicales de la Universidad de Salamanca), Facultad de Farmacia, Universidad de Salamanca, Salamanca, Spain
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Diagnostics for schistosomiasis in Africa and Arabia: a review of present options in control and future needs for elimination. Parasitology 2014; 141:1947-61. [PMID: 25158604 DOI: 10.1017/s0031182014001152] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Within the World Health Organization 2012-2020 roadmap for control and elimination of schistosomiasis, the scale-up of mass drug administration with praziquantel is set to change the epidemiological landscape across Africa and Arabia. Central in measuring progress is renewed emphasis upon diagnostics which operate at individual, community and environmental levels by assessing reductions in disease, infections and parasite transmission. However, a fundamental tension is revealed between levels for present diagnostic tools, and methods applied in control settings are not necessarily adequate for application in elimination scenarios. Indeed navigating the transition from control to elimination needs careful consideration and planning. In the present context of control, we review current options for diagnosis of schistosomiasis at different levels, highlighting several strengths and weaknesses therein. Future challenges in elimination are raised and we propose that more cost-effective diagnostics and clinical staging algorithms are needed. Using the Kingdom of Saudi Arabia as a contemporary example, embedding new diagnostic methods within the primary care health system is discussed with reference to both urogenital and intestinal schistosomiasis.
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Mickum ML, Prasanphanich NS, Heimburg-Molinaro J, Leon KE, Cummings RD. Deciphering the glycogenome of schistosomes. Front Genet 2014; 5:262. [PMID: 25147556 PMCID: PMC4122909 DOI: 10.3389/fgene.2014.00262] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Accepted: 07/15/2014] [Indexed: 11/16/2022] Open
Abstract
Schistosoma mansoni and other Schistosoma sp. are multicellular parasitic helminths (worms) that infect humans and mammals worldwide. Infection by these parasites, which results in developmental maturation and sexual differentiation of the worms over a period of 5–6 weeks, induces antibodies to glycan antigens expressed in surface and secreted glycoproteins and glycolipids. There is growing interest in defining these unusual parasite-synthesized glycan antigens and using them to understand immune responses, their roles in immunomodulation, and in using glycan antigens as potential vaccine targets. A key problem in this area, however, has been the lack of information about the enzymes involved in elaborating the complex repertoire of glycans represented by the schistosome glycome. Recent availability of the nuclear genome sequences for Schistosoma sp. has created the opportunity to define the glycogenome, which represents the specific genes and cognate enzymes that generate the glycome. Here we describe the current state of information in regard to the schistosome glycogenome and glycome and highlight the important classes of glycans and glycogenes that may be important in their generation.
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Affiliation(s)
- Megan L Mickum
- Department of Biochemistry, Emory University School of Medicine Atlanta, GA, USA
| | - Nina S Prasanphanich
- Department of Biochemistry, Emory University School of Medicine Atlanta, GA, USA
| | | | - Kristoffer E Leon
- Department of Biochemistry, Emory University School of Medicine Atlanta, GA, USA
| | - Richard D Cummings
- Department of Biochemistry, Emory University School of Medicine Atlanta, GA, USA
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Poole H, Terlouw DJ, Naunje A, Mzembe K, Stanton M, Betson M, Lalloo DG, Stothard JR. Schistosomiasis in pre-school-age children and their mothers in Chikhwawa district, Malawi with notes on characterization of schistosomes and snails. Parasit Vectors 2014; 7:153. [PMID: 24690282 PMCID: PMC4230191 DOI: 10.1186/1756-3305-7-153] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 03/17/2014] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND To complement ongoing schistosomiasis control within national control programmes (NCPs) that administer praziquantel to school-age children, assessing the risk and extent of schistosomiasis in pre-school-age children (PSAC) is important. METHODS In June 2012, schistosomiasis in Chikhwawa district, Malawi was assessed across 12 villages examining pre-school-age children (PSAC) and their mothers by serological and parasitological diagnosis, as supplemented with urine-antigen and questionnaire-interview methods. Urinary tract morbidity was inferred by haematuria and albuminuria assays. RESULTS In total, 49.5% (CI₉₅ 42.6-56.4) of 208 PSAC and 94.5% (CI₉₅ 90.9-98.1) of 165 mothers were seropositive for schistosomiasis, in 2 villages seroprevalence exceeded 75% in PSAC. Egg-patent urogenital and intestinal schistosomiasis was observed; 17.7% (CI₉₅ 12.4-23.2) of PSAC and 45.1% (CI₉₅ 37.4-52.8) of mothers having active schistosomiasis by parasitological and urine-antigen testing combined. PSAC often had extensive daily water contact and many (~25%) had haematuria and albuminuria. As eggs with an atypical morphology of Schistosoma haematobium were observed, a general selection of schistosome eggs was characterized by DNA barcoding, finding Group I S. haematobium and Group IV and V S. mansoni. Malacological surveys encountered several populations of Bulinus globosus but failed to find Biomphalaria. CONCLUSIONS Both PSAC and their mothers appear to be at significant risk of schistosomiasis and should be considered for treatment within the NCP of Malawi.
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Affiliation(s)
- Helen Poole
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Dianne J Terlouw
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, PO Box 30096, Chichiri, Blantyre 3, Malawi
| | - Andrew Naunje
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, PO Box 30096, Chichiri, Blantyre 3, Malawi
| | - Kondwani Mzembe
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, PO Box 30096, Chichiri, Blantyre 3, Malawi
| | - Michelle Stanton
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Martha Betson
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - David G Lalloo
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - J Russell Stothard
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
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Comparing parasitological vs serological determination of Schistosoma haematobium infection prevalence in preschool and primary school-aged children: implications for control programmes. Parasitology 2014; 141:1962-70. [PMID: 24679476 PMCID: PMC4255325 DOI: 10.1017/s0031182014000213] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
To combat schistosomiasis, the World Health Organization (WHO) recommends that infection levels are determined prior to designing and implementing control programmes, as the treatment regimens depend on the population infection prevalence. However, the sensitivity of the parasitological infection diagnostic method is less reliable when infection levels are low. The aim of this study was to compare levels of Schistosoma haematobium infection obtained by the parasitological method vs serological technique. Infection levels in preschool and primary school-aged children and their implications for control programmes were also investigated. Infection prevalence based on serology was significantly higher compared with that based on parasitology for both age groups. The difference between infection levels obtained using the two methods increased with age. Consequentially, in line with the WHO guidelines, the serological method suggested a more frequent treatment regimen for this population compared with that implied by the parasitological method. These findings highlighted the presence of infection in children aged ⩽5 years, further reiterating the need for their inclusion in control programmes. Furthermore, this study demonstrated the importance of using sensitive diagnostic methods as this has implications on the required intervention controls for the population.
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Parasite-derived microRNAs in host serum as novel biomarkers of helminth infection. PLoS Negl Trop Dis 2014; 8:e2701. [PMID: 24587461 PMCID: PMC3930507 DOI: 10.1371/journal.pntd.0002701] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 01/03/2014] [Indexed: 02/06/2023] Open
Abstract
Background MicroRNAs (miRNAs) are a class of short non-coding RNA that play important roles in disease processes in animals and are present in a highly stable cell-free form in body fluids. Here, we examine the capacity of host and parasite miRNAs to serve as tissue or serum biomarkers of Schistosoma mansoni infection. Methods/Principal Findings We used Exiqon miRNA microarrays to profile miRNA expression in the livers of mice infected with S. mansoni at 7 weeks post-infection. Thirty-three mouse miRNAs were differentially expressed in infected compared to naïve mice (>2 fold change, p<0.05) including miR-199a-3p, miR-199a-5p, miR-214 and miR-21, which have previously been associated with liver fibrosis in other settings. Five of the mouse miRNAs were also significantly elevated in serum by twelve weeks post-infection. Sequencing of small RNAs from serum confirmed the presence of these miRNAs and further revealed eleven parasite-derived miRNAs that were detectable by eight weeks post infection. Analysis of host and parasite miRNA abundance by qRT-PCR was extended to serum of patients from low and high infection sites in Zimbabwe and Uganda. The host-derived miRNAs failed to distinguish uninfected from infected individuals. However, analysis of three of the parasite-derived miRNAs (miR-277, miR-3479-3p and bantam) could detect infected individuals from low and high infection intensity sites with specificity/sensitivity values of 89%/80% and 80%/90%, respectively. Conclusions This work identifies parasite-derived miRNAs as novel markers of S. mansoni infection in both mice and humans, with the potential to be used with existing techniques to improve S. mansoni diagnosis. In contrast, although host miRNAs are differentially expressed in the liver during infection their abundance levels in serum are variable in human patients and may be useful in cases of extreme pathology but likely hold limited value for detecting prevalence of infection. Schistosomiasis is a chronic disease caused by blood flukes that affects over 200 million people worldwide, of which 90% live in Sub-Saharan Africa. In the field setting schistosomiasis caused by S. mansoni is diagnosed by detection of parasite eggs in stool samples using microscopic techniques. Here we investigate the potential of microRNAs (miRNAs), a class of short noncoding RNAs, to act as biomarkers of S. mansoni infection. We have identified a specific subset of murine miRNAs whose expression is significantly altered in the liver between 6–12 weeks post infection. However their abundance in serum is not significantly different between naïve and S. mansoni-infected mice until twelve weeks post infection and they do not display consistent differential abundance in the serum of infected versus uninfected humans. In contrast, three parasite-derived miRNAs (miR-277, bantam and miR-3479-3p) were detected in the serum of infected mice and human patients and the combined detection of these miRNAs could distinguish S. mansoni infected from uninfected individuals from low and high infection intensity areas with 89%/80% or 80%/90% specificity/sensitivity, respectively. These results demonstrate that miRNAs of parasite origin are a new class of serum biomarker for detecting S. mansoni and likely other helminth infections.
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Urogenital schistosomiasis and urological assessment of hematuria in preschool-aged children in rural communities of Nigeria. J Pediatr Urol 2014; 10:88-93. [PMID: 23891456 DOI: 10.1016/j.jpurol.2013.06.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 06/16/2013] [Indexed: 11/21/2022]
Abstract
OBJECTIVE The study evaluates the prevalence of urogenital schistosomiasis and diagnostic performance of chemical reagent strips used for disease diagnosis in preschool-aged children (≤ 5 years) in Nigeria rural communities. PATIENTS AND METHODS Urine samples from 419 children were observed microscopically for Schistosoma haematobium and screened for hematuria using standard urine chemical reagent strips. RESULTS Prevalence and intensity of infection were 9.8% and 14.4 eggs/10 ml of urine, respectively. Prevalence of infection was similar in girls (10%) and boys (9.6%) (p > 0.05). The intensity of infection was higher in boys (17.1 eggs/10 ml of urine) than in girls (12.8 eggs/10 ml of urine); however, this was not gender dependent (p > 0.05). The occurrence of hematuria was not associated with gender (p > 0.05), but was associated with prevalence of infection (p < 0.05). CONCLUSION Infection with S. haematobium occurs early in life in the communities and although intensity of infection is low, it could have serious implications in disease transmission. Hematuria, although moderately sensitive to infection, is an important morbidity indicator of urogenital schistosomiasis in the study population.
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Mutapi F. Improving diagnosis of urogenital schistosome infection. Expert Rev Anti Infect Ther 2014; 9:863-5. [DOI: 10.1586/eri.11.101] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Koukounari A, Donnelly CA, Moustaki I, Tukahebwa EM, Kabatereine NB, Wilson S, Webster JP, Deelder AM, Vennervald BJ, van Dam GJ. A latent Markov modelling approach to the evaluation of circulating cathodic antigen strips for schistosomiasis diagnosis pre- and post-praziquantel treatment in Uganda. PLoS Comput Biol 2013; 9:e1003402. [PMID: 24367250 PMCID: PMC3868541 DOI: 10.1371/journal.pcbi.1003402] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 10/28/2013] [Indexed: 01/19/2023] Open
Abstract
Regular treatment with praziquantel (PZQ) is the strategy for human schistosomiasis control aiming to prevent morbidity in later life. With the recent resolution on schistosomiasis elimination by the 65th World Health Assembly, appropriate diagnostic tools to inform interventions are keys to their success. We present a discrete Markov chains modelling framework that deals with the longitudinal study design and the measurement error in the diagnostic methods under study. A longitudinal detailed dataset from Uganda, in which one or two doses of PZQ treatment were provided, was analyzed through Latent Markov Models (LMMs). The aim was to evaluate the diagnostic accuracy of Circulating Cathodic Antigen (CCA) and of double Kato-Katz (KK) faecal slides over three consecutive days for Schistosoma mansoni infection simultaneously by age group at baseline and at two follow-up times post treatment. Diagnostic test sensitivities and specificities and the true underlying infection prevalence over time as well as the probabilities of transitions between infected and uninfected states are provided. The estimated transition probability matrices provide parsimonious yet important insights into the re-infection and cure rates in the two age groups. We show that the CCA diagnostic performance remained constant after PZQ treatment and that this test was overall more sensitive but less specific than single-day double KK for the diagnosis of S. mansoni infection. The probability of clearing infection from baseline to 9 weeks was higher among those who received two PZQ doses compared to one PZQ dose for both age groups, with much higher re-infection rates among children compared to adolescents and adults. We recommend LMMs as a useful methodology for monitoring and evaluation and treatment decision research as well as CCA for mapping surveys of S. mansoni infection, although additional diagnostic tools should be incorporated in schistosomiasis elimination programs. Schistosomiasis remains one of the most prevalent parasitic diseases in developing countries, with Schistosoma mansoni being the most widespread of the human-infecting schistosomes. For the routine surveillance of human S. mansoni infection more “field-applicable,” sensitive, and cost-effective diagnostics that replicate faecal samples over several consecutive days [the Kato-Katz (KK) method], are needed. We propose a statistical modelling framework in order to evaluate the diagnostic performance of the urine strip test for Circulating Cathodic Antigen (CCA) and single-day double KK measurements over three consecutive days for the diagnosis of S. mansoni infection in two different age groups from Uganda pre- and post- praziquantel (PZQ) treatment. We demonstrate that CCA is an appropriate tool for mapping surveys of S. mansoni infection. Our findings should allow for evaluation of the risk of potential misinterpretation with regards to diagnosis of S. mansoni infection through CCA or KK in this endemic setting pre- and post- PZQ treatment as the numbers and infection intensities are brought down, bridging existing important gaps in schistosomiasis diagnostics research. More generally, the proposed statistical analysis can reveal important biological insights from other diseases without gold standard diagnostic tools whenever longitudinal data are available.
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Affiliation(s)
- Artemis Koukounari
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
- Department of Statistics, London School of Economics and Political Science, London, United Kingdom
- * E-mail:
| | - Christl A. Donnelly
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Irini Moustaki
- Department of Statistics, London School of Economics and Political Science, London, United Kingdom
| | - Edridah M. Tukahebwa
- Schistosomiasis Control Initiative at Vector Control Division – Ministry of Health, Kampala, Uganda
| | - Narcis B. Kabatereine
- Schistosomiasis Control Initiative at Vector Control Division – Ministry of Health, Kampala, Uganda
| | - Shona Wilson
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Joanne P. Webster
- Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - André M. Deelder
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - Birgitte J. Vennervald
- Section for Parasitology and Aquatic Diseases, University of Copenhagen, Copenhagen, Denmark
| | - Govert J. van Dam
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
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Betson M, Sousa-Figueiredo JC, Kabatereine NB, Stothard JR. New insights into the molecular epidemiology and population genetics of Schistosoma mansoni in Ugandan pre-school children and mothers. PLoS Negl Trop Dis 2013; 7:e2561. [PMID: 24349589 PMCID: PMC3861247 DOI: 10.1371/journal.pntd.0002561] [Citation(s) in RCA: 18] [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: 05/10/2013] [Accepted: 10/14/2013] [Indexed: 12/22/2022] Open
Abstract
Significant numbers of pre-school children are infected with Schistosoma mansoni in sub-Saharan Africa and are likely to play a role in parasite transmission. However, they are currently excluded from control programmes. Molecular phylogenetic studies have provided insights into the evolutionary origins and transmission dynamics of S. mansoni, but there has been no research into schistosome molecular epidemiology in pre-school children. Here, we investigated the genetic diversity and population structure of S. mansoni in pre-school children and mothers living in lakeshore communities in Uganda and monitored for changes over time after praziquantel treatment. Parasites were sampled from children (<6 years) and mothers enrolled in the longitudinal Schistosomiasis Mothers and Infants Study at baseline and at 6-, 12- and 18-month follow-up surveys. 1347 parasites from 35 mothers and 45 children were genotyped by direct sequencing of the cytochrome c oxidase (cox1) gene. The cox1 region was highly diverse with over 230 unique sequences identified. Parasite populations were genetically differentiated between lakes and non-synonymous mutations were more diverse at Lake Victoria than Lake Albert. Surprisingly, parasite populations sampled from children showed a similar genetic diversity to those sampled from mothers, pointing towards a non-linear relationship between duration of exposure and accumulation of parasite diversity. The genetic diversity six months after praziquantel treatment was similar to pre-treatment diversity. Our results confirm the substantial genetic diversity of S. mansoni in East Africa and provide significant insights into transmission dynamics within young children and mothers, important information for schistosomiasis control programmes. Many pre-school children in sub-Saharan Africa are infected with the parasite Schistosoma mansoni, which causes intestinal schistosomiasis. However, there has been no work published on the molecular epidemiology of Schistosoma in children under six or the role that these children play in parasite transmission. We analysed the genetic structure of parasite populations collected from mothers and young children living on the shores of Lakes Albert and Victoria in Uganda. Parasite populations were different at the two lakes indicating that there is little flow of parasite genes between the lakes. We were surprised to discover a large amount of genetic variation in parasites sampled from both children and mothers, suggesting that genetic variation is not directly related to duration of exposure to infested water. In addition, we found some evidence that young children are involved in S. mansoni transmission. The substantial genetic variation of S. mansoni in young children suggests that these parasites could be operating as a source of a variety of genetic traits, including drug susceptibility. Overall our findings offer significant insights into population genetics of S. mansoni in pre-school children and their mothers and provide important information for effective control of intestinal schistosomiasis.
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Affiliation(s)
- Martha Betson
- Department of Production and Population Health, The Royal Veterinary College, Hatfield, Hertfordshire, United Kingdom
| | - Jose C. Sousa-Figueiredo
- Parasitology Department, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | - J. Russell Stothard
- Parasitology Department, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- * E-mail:
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