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Kabbas-Piñango E, Arinaitwe M, van Dam GJ, Moses A, Namukuta A, Nankasi AB, Mwima NK, Besigye F, Prada JM, Lamberton PHL. Reproducibility matters: intra- and inter-sample variation of the point-of-care circulating cathodic antigen test in two Schistosoma mansoni endemic areas in Uganda. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220275. [PMID: 37598698 PMCID: PMC10440168 DOI: 10.1098/rstb.2022.0275] [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: 02/02/2023] [Accepted: 07/19/2023] [Indexed: 08/22/2023] Open
Abstract
Over 240 million people are infected with schistosomiasis. Detecting Schistosoma mansoni eggs in stool using Kato-Katz thick smears (Kato-Katzs) is highly specific but lacks sensitivity. The urine-based point-of-care circulating cathodic antigen test (POC-CCA) has higher sensitivity, but issues include specificity, discrepancy between batches and interpretation of trace results. A semi-quantitative G-score and latent class analyses making no assumptions about trace readings have helped address some of these issues. However, intra-sample and inter-sample variation remains unknown for POC-CCAs. We collected 3 days of stool and urine from 349 and 621 participants, from high- and moderate-endemicity areas, respectively. We performed duplicate Kato-Katzs and one POC-CCA per sample. In the high-endemicity community, we also performed three POC-CCA technical replicates on one urine sample per participant. Latent class analysis was performed to estimate the relative contribution of intra- (test technical reproducibility) and inter-sample (day-to-day) variation on sensitivity and specificity. Within-sample variation for Kato-Katzs was higher than between-sample, with the opposite true for POC-CCAs. A POC-CCA G3 threshold most accurately assesses individual infections. However, to reach the WHO target product profile of the required 95% specificity for prevalence and monitoring and evaluation, a threshold of G4 is needed, but at the cost of reducing sensitivity. This article is part of the theme issue 'Challenges and opportunities in the fight against neglected tropical diseases: a decade from the London Declaration on NTDs'.
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Affiliation(s)
- Elías Kabbas-Piñango
- School of Biodiversity, One Health & Veterinary Medicine, Wellcome Centre for Integrative Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Moses Arinaitwe
- Vector Borne and NTD Control Division, Bilharzia and Worm Control Program Uganda, Ministry of Health, PO Box 1661, Kampala, Uganda
| | - Govert J. van Dam
- Department of Parasitology, Leiden University Medical Center, Leiden, 2333 ZA, The Netherlands
| | - Adriko Moses
- Vector Borne and NTD Control Division, Bilharzia and Worm Control Program Uganda, Ministry of Health, PO Box 1661, Kampala, Uganda
| | - Annet Namukuta
- Vector Borne and NTD Control Division, Bilharzia and Worm Control Program Uganda, Ministry of Health, PO Box 1661, Kampala, Uganda
| | - Andrina Barungi Nankasi
- Vector Borne and NTD Control Division, Bilharzia and Worm Control Program Uganda, Ministry of Health, PO Box 1661, Kampala, Uganda
| | - Nicholas Khayinja Mwima
- Vector Borne and NTD Control Division, Bilharzia and Worm Control Program Uganda, Ministry of Health, PO Box 1661, Kampala, Uganda
| | - Fred Besigye
- Vector Borne and NTD Control Division, Bilharzia and Worm Control Program Uganda, Ministry of Health, PO Box 1661, Kampala, Uganda
| | - Joaquin M. Prada
- Department of Comparative Biomedical Sciences, Faculty of Health & Medical Sciences, University of Surrey, Guildford GU2 7XH, UK
| | - Poppy H. L. Lamberton
- School of Biodiversity, One Health & Veterinary Medicine, Wellcome Centre for Integrative Parasitology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
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Saad El-Din MI, Gad EL-Hak HN, Ghobashy MA, Elrayess RA. Parasitological and histopathological studies to the effect of aqueous extract of Moringa oleifera Lam. leaves combined with praziquantel therapy in modulating the liver and spleen damage induced by Schistosoma mansoni to male mice. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:15548-15560. [PMID: 36169837 PMCID: PMC9908685 DOI: 10.1007/s11356-022-23098-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 09/14/2022] [Indexed: 06/16/2023]
Abstract
This study assessed the effectiveness of an aqueous extract of Moringa Oleifera Lam. leaves (MOL) alone or in combination with praziquantel (PZQ) drug targeting-infected mice with Schistosoma mansoni-induced liver and spleen damage. Mice were divided into eight groups control mice group treated orally with saline. PZQ group: non-infected mice treated orally with 300 mg/kg bwt PZQ three consecutive days. MOL group: non-infected mice treated orally with 150 mg/kg bwt MOL extract for 15 days. PZQ/ MOL group: non-infected mice treated orally with 300 mg/kg bwt PZQ for three consecutive days and 150 mg/kg bwt MOL extract for 15 days. IF group: infected mice with 100 cercariae/mouse of the Egyptian strain of S. mansoni. IF/PZQ group infected mice with S. mansoni cercariae and treated orally with 300 mg/kg bwt PZQ for three consecutive days. IF/MOL group: infected mice with S. mansoni cercariae treated orally with 150 mg/kg bwt MOL extract for 15 days. IF/PZQ +MOL group: infected mice with S. mansoni cercariae treated orally with 300 mg/kg bwt PZQ for three consecutive days and 150 mg/kg bwt MOL extract for 15 days. Blood, liver, spleen, worm, and eggs were collected at the end of the experimental period. Treatment of infected mice with MOL and PZQ together significantly reduced the number of ova/g tissue and eliminated the parasites. In addition, the liver and spleen of infected mice showed less histopathological alteration and immunohistochemical expression of nuclear factor kappa β (NF-Kβ). We can conclude that MOL extract combined with PZ has a curative effect on S. mansoni infection and helped to lessen its pathological effects.
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Affiliation(s)
| | - Heba N. Gad EL-Hak
- Zoology Department, Faculty of Science, Suez Canal University, Ismailia, Egypt
| | - Mahi A. Ghobashy
- Zoology Department, Faculty of Science, Suez Canal University, Ismailia, Egypt
| | - Ranwa A. Elrayess
- Zoology Department, Faculty of Science, Suez Canal University, Ismailia, Egypt
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Evaluation of Two Different Strategies for Schistosomiasis Screening in High-Risk Groups in a Non-Endemic Setting. Trop Med Infect Dis 2023; 8:tropicalmed8010044. [PMID: 36668951 PMCID: PMC9862038 DOI: 10.3390/tropicalmed8010044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/23/2022] [Accepted: 12/30/2022] [Indexed: 01/09/2023] Open
Abstract
A consensus on the recommended screening algorithms for schistosomiasis in asymptomatic high-risk subjects in non-endemic areas is lacking. The objective of this study was to evaluate the real-life performance of direct microscopy and ELISA serology for schistosomiasis screening in a high-risk population in a non-endemic setting. A retrospective cohort study was conducted in two out-patient Tropical Medicine units in Barcelona (Spain) from 2014 to 2017. Asymptomatic adults arriving from the Sub-Saharan region were included. Schistosomiasis screening was conducted according to clinical practice following a different strategy in each setting: (A) feces and urine direct examination plus S. mansoni serology if non-explained eosinophilia was present and (B) S. mansoni serology plus uroparasitological examination as the second step in case of a positive serology. Demographic, clinical and laboratory features were collected. Schistosomiasis cases, clinical management and a 24 month follow-up were recorded for each group. Four-hundred forty individuals were included. The patients were mainly from West African countries. Fifty schistosomiasis cases were detected (11.5% group A vs. 4 % group B, p = 0.733). When both microscopic and serological techniques were performed, discordant results were recorded in 18.4% (16/88). Schistosomiasis cases were younger (p < 0.001) and presented eosinophilia and elevated IgE (p < 0.001) more frequently. Schistosomiasis is a frequent diagnosis among high-risk populations. Serology achieves a similar performance to direct diagnosis for the screening of schistosomiasis in a high-risk population.
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Fine-scale mapping of Schistosoma mansoni infections and infection intensities in sub-districts of Makenene in the Centre region of Cameroon. PLoS Negl Trop Dis 2022; 16:e0010852. [PMID: 36227962 PMCID: PMC9595529 DOI: 10.1371/journal.pntd.0010852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 10/25/2022] [Accepted: 09/28/2022] [Indexed: 11/06/2022] Open
Abstract
Background Schistosomiasis control relies mainly on mass drug administration of Praziquantel (PZQ) to school aged children (SAC). Although precision mapping has recently guided decision making, the sub-districts and the epidemiological differences existing between bio-ecological settings in which infected children come from were not taken into consideration. This study was designed to fill this gap by using POC-CCA and KK to comparatively determine the prevalence and infection intensities of Schistosoma mansoni (S. mansoni) and to perform fine-scale mapping of S. mansoni infections and its infection intensities with the overarching goal of identifying sub-districts presenting high transmission risk where control operations must be boosted to achieve schistosomiasis elimination. Methodology During a cross- sectional study conducted in Makenene, 1773 stool and 2253 urine samples were collected from SAC of ten primary schools. S. mansoni infections were identified using the point of care circulating cathodic antigen (POC-CCA) and Kato-Katz (KK) test respectively on urine and stool samples. Geographical coordinates of houses of infected SAC were recorded using a global position system device. Schistosome infections and infection intensities were map using QGIS software. Results The prevalence of S. mansoni inferred from POC-CCA and KK were 51.3% and 7.3% respectively. Most infected SAC and those bearing heavy infections intensities were clustered in sub-districts of Baloua, Mock-sud and Carrière. Houses with heavily-infected SAC were close to risky biotopes. Conclusion This study confirms the low sensitivity of KK test compared to POC-CCA to accurately identify children with schistosome infection and bearing different schistosome burden. Fine-scale mapping of schistosome infections and infection intensities enabled to identify high transmission sub-districts where control measures must be boosted to reach schistosomiasis elimination. Although some disparities in terms of prevalence and infection intensities have been acknowledged within and between schistosomiasis endemic areas, the current control measures did not take into consideration the disparities within endemic areas. To improve the control of schistosomiasis, a fine-scale mapping of schistosome infections and their intensities were undertaken using KK in comparison to POC-CCA to identify sub-districts with potential high transmission risk and where control operations must be boosted to achieve elimination. After the identification of schistosome infections by the point of care circulating cathodic antigen (POC-CCA) and Kato-Katz (KK) test, the geographical coordinates of each infected child’s house were recorded using a global position system device (GPS). QGIS software was used to create a map showing schistosome infections and their infection intensities. Our results showed that the majority of infected children and those bearing heavy infection intensities were clustering mostly in Baloua, Carrière and Mock-Sud sub-districts of Makenene while children with light and moderate infection intensity were widely distributed and far away from risky biotopes. The fine-scale mapping of schistosome infections and their infection intensities enable to identify hotspot transmission sites where control strategy must be boosted to achieve the elimination of intestinal schistosomiasis in Makenene.
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Summers S, Bhattacharyya T, Allan F, Stothard JR, Edielu A, Webster BL, Miles MA, Bustinduy AL. A review of the genetic determinants of praziquantel resistance in Schistosoma mansoni: Is praziquantel and intestinal schistosomiasis a perfect match? FRONTIERS IN TROPICAL DISEASES 2022. [DOI: 10.3389/fitd.2022.933097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Schistosomiasis is a neglected tropical disease (NTD) caused by parasitic trematodes belonging to the Schistosoma genus. The mainstay of schistosomiasis control is the delivery of a single dose of praziquantel (PZQ) through mass drug administration (MDA) programs. These programs have been successful in reducing the prevalence and intensity of infections. Due to the success of MDA programs, the disease has recently been targeted for elimination as a public health problem in some endemic settings. The new World Health Organization (WHO) treatment guidelines aim to provide equitable access to PZQ for individuals above two years old in targeted areas. The scale up of MDA programs may heighten the drug selection pressures on Schistosoma parasites, which could lead to the emergence of PZQ resistant schistosomes. The reliance on a single drug to treat a disease of this magnitude is worrying should drug resistance develop. Therefore, there is a need to detect and track resistant schistosomes to counteract the threat of drug resistance to the WHO 2030 NTD roadmap targets. Until recently, drug resistance studies have been hindered by the lack of molecular markers associated with PZQ resistance. This review discusses recent significant advances in understanding the molecular basis of PZQ action in S. mansoni and proposes additional genetic determinants associated with PZQ resistance. PZQ resistance will also be analyzed in the context of alternative factors that may decrease efficacy within endemic field settings, and the most recent treatment guidelines recommended by the WHO.
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O'Brien PP, Bowman J, Newar SL, Garroway CJ. Testing the parasite-mediated competition hypothesis between sympatric northern and southern flying squirrels. Int J Parasitol Parasites Wildl 2022; 17:83-90. [PMID: 34987957 PMCID: PMC8695264 DOI: 10.1016/j.ijppaw.2021.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 11/01/2021] [Accepted: 11/09/2021] [Indexed: 12/01/2022]
Abstract
Competition is a driving factor in shaping ecological communities and may act directly or indirectly through apparent competition. We examined a classic example of parasite-mediated competition between northern (Glaucomys sabrinus) and southern flying squirrels (G. volans) via the intestinal nematode, Strongyloides robustus, and tested whether it could act as a species barrier in a flying squirrel hybrid zone. We live-trapped flying squirrels (G. sabrinus and G. volans), grey squirrels (Sciurus carolinensis), red squirrels (Tamiasciurus hudsonicus), and chipmunks (Tamias striatus) from June–September 2019 at 30 woodlots in Ontario, Canada. Fecal samples from squirrels were collected and analyzed for the presence of endoparasite eggs. For each individual, we calculated Scaled Mass Index (SMI) as a measure of body condition to assess the effect of S. robustus on squirrels. We found eggs of S. robustus in all species except chipmunks. Infection with S. robustus did not appear to affect body condition of southern flying squirrels and grey squirrels, but we did find a weak negative effect on northern flying squirrels and red squirrels. Despite a weak asymmetric effect of S. robustus on flying squirrels, we did not find any evidence that parasite-mediated competition could lead to competitive exclusion from woodlots. Furthermore, S. robustus eggs were common in feces of the red squirrel, a species largely sympatric with northern flying squirrel. Strongyloides robustus was detected in 4 squirrel species. The highest prevalence of S. robustus was found in red squirrels and northern flying squirrels. Body condition was lowest in red squirrels and northern flying squirrels infected with S. robustus. No evidence of parasite-mediated competition between sympatric flying squirrels leading to competitive exclusion.
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Affiliation(s)
- Paul P O'Brien
- Department of Biological Sciences, University of Manitoba, Sifton Road, Winnipeg, Manitoba, R3T 2N2, Canada
| | - Jeff Bowman
- Environmental & Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, Ontario, K9L 0G2, Canada
- Wildlife Research & Monitoring Section, Ontario Ministry of Northern Development, Mines, Natural Resources & Forestry, Trent University, 2140 East Bank Drive, Peterborough, Ontario, K9L 0G2, Canada
| | - Sasha L Newar
- Environmental & Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, Ontario, K9L 0G2, Canada
| | - Colin J Garroway
- Department of Biological Sciences, University of Manitoba, Sifton Road, Winnipeg, Manitoba, R3T 2N2, Canada
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Gordon CA, Williams GM, Gray DJ, Clements ACA, Zhou XN, Li Y, Utzinger J, Kurscheid J, Forsyth S, Addis Alene K, Zhou J, Li Z, Li G, Lin D, Lou Z, Li S, Ge J, Xu J, Yu X, Hu F, Xie S, Chen J, Shi T, Li C, Zheng H, McManus DP. Schistosomiasis in the People's Republic of China - down but not out. Parasitology 2022; 149:218-233. [PMID: 35234601 PMCID: PMC11010531 DOI: 10.1017/s0031182021001724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 09/30/2021] [Accepted: 10/01/2021] [Indexed: 11/06/2022]
Abstract
Schistosomiasis has been subjected to extensive control efforts in the People's Republic of China (China) which aims to eliminate the disease by 2030. We describe baseline results of a longitudinal cohort study undertaken in the Dongting and Poyang lakes areas of central China designed to determine the prevalence of Schistosoma japonicum in humans, animals (goats and bovines) and Oncomelania snails utilizing molecular diagnostics procedures. Data from the Chinese National Schistosomiasis Control Programme (CNSCP) were compared with the molecular results obtained.Sixteen villages from Hunan and Jiangxi provinces were surveyed; animals were only found in Hunan. The prevalence of schistosomiasis in humans was 1.8% in Jiangxi and 8.0% in Hunan determined by real-time polymerase chain reaction (PCR), while 18.3% of animals were positive by digital droplet PCR. The CNSCP data indicated that all villages harboured S. japonicum-infected individuals, detected serologically by indirect haemagglutination assay (IHA), but very few, if any, of these were subsequently positive by Kato-Katz (KK).Based on the outcome of the IHA and KK results, the CNSCP incorporates targeted human praziquantel chemotherapy but this approach can miss some infections as evidenced by the results reported here. Sensitive molecular diagnostics can play a key role in the elimination of schistosomiasis in China and inform control measures allowing for a more systematic approach to treatment.
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Affiliation(s)
- Catherine A. Gordon
- Department of Immunology, Molecular Parasitology Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Gail M. Williams
- School of Population Health, Discipline of Epidemiology and Biostatistics, University of Queensland, Brisbane, Australia
| | - Darren J. Gray
- Department of Global Health, Research School of Population Health, Australian National University, Canberra, Australia
| | | | - Xiao-Nong Zhou
- National Institute of Parasitic Diseases, Shanghai, People's Republic of China
| | - Yuesheng Li
- Department of Immunology, Molecular Parasitology Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Australia
- Hunan Institute of Schistosomiasis Control, Yueyang, Hunan, People's Republic of China
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Johanna Kurscheid
- Department of Global Health, Research School of Population Health, Australian National University, Canberra, Australia
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Simon Forsyth
- School of Population Health, Discipline of Epidemiology and Biostatistics, University of Queensland, Brisbane, Australia
| | | | - Jie Zhou
- Hunan Institute of Schistosomiasis Control, Yueyang, Hunan, People's Republic of China
| | - Zhaojun Li
- Jiangxi Institute of Parasitic Diseases, Jiangxi, People's Republic of China
| | - Guangpin Li
- Hunan Institute of Schistosomiasis Control, Yueyang, Hunan, People's Republic of China
| | - Dandan Lin
- Jiangxi Institute of Parasitic Diseases, Jiangxi, People's Republic of China
| | - Zhihong Lou
- Hunan Institute of Schistosomiasis Control, Yueyang, Hunan, People's Republic of China
| | - Shengming Li
- Hunan Institute of Schistosomiasis Control, Yueyang, Hunan, People's Republic of China
| | - Jun Ge
- Jiangxi Institute of Parasitic Diseases, Jiangxi, People's Republic of China
| | - Jing Xu
- National Institute of Parasitic Diseases, Shanghai, People's Republic of China
| | - Xinling Yu
- Hunan Institute of Schistosomiasis Control, Yueyang, Hunan, People's Republic of China
| | - Fei Hu
- Jiangxi Institute of Parasitic Diseases, Jiangxi, People's Republic of China
| | - Shuying Xie
- Jiangxi Institute of Parasitic Diseases, Jiangxi, People's Republic of China
| | - Jie Chen
- Chinese National Human Genome Center, Shanghai, People's Republic of China
| | - Tao Shi
- Chinese National Human Genome Center, Shanghai, People's Republic of China
| | - Chong Li
- Chinese National Human Genome Center, Shanghai, People's Republic of China
| | - Huajun Zheng
- Chinese National Human Genome Center, Shanghai, People's Republic of China
| | - Donald P. McManus
- Department of Immunology, Molecular Parasitology Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Australia
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Risk Factors and Spatial Distribution of Schistosoma mansoni Infection among Preschool-Aged Children in Blapleu, Biankouma District, Western Côte d'Ivoire. J Trop Med 2021; 2021:6224401. [PMID: 34876909 PMCID: PMC8645407 DOI: 10.1155/2021/6224401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 09/21/2021] [Indexed: 11/24/2022] Open
Abstract
Schistosoma mansoni infection is common among school-age children (SAC) in western Côte d'Ivoire. Little is known on the infection rate of preschool-aged children (PSAC) due to epidemiological data deficiency and nonappropriate formulation of the drug. Thus, mass drug administration for schistosomiasis control mainly targets SAC. This study aims to identify the risk factors and spatial distribution of S. mansoni infection among PSAC in Blapleu, endemic foci of S. mansoni. We carried out a cross-sectional study in households with PSAC aged 1–6 years. A structured questionnaire was administered to mothers/guardians to obtain data on sociodemographics and water contact behaviour of children. Point-of-care circulating cathodic antigen (POC-CCA) immunodiagnostic test in urine and Kato-Katz (K-K) method with stool were used for S. mansoni infection diagnosis. Multiple logistic regression analysis was performed to determine the relationship between S. mansoni infection and sociodemographic data. Coordinates recorded by a Global Positioning System of households, water source points, and infected PSAC were used to map the spatial distribution of S. mansoni infection cases. This study was conducted with 350 PSAC aged 1–6 years. The overall infection prevalence of S. mansoni varies from 31.43% with the K-K method to 62.86% with the POC-CCA. PSAC aged 2–6 years were highly infected with S. mansoni than those aged 1-2 years (OR = 14.24, 95% CI: 5.85–34.64). PSAC who did not have access and who do not live close to the infected water source were at a significant lower risk of S. mansoni infection (OR = 0.13, 95% CI: 0.057–0.30). The main purpose of water contact of PSAC was to help their mother for laundry that occurs weekly. In Blapleu, a high risk of S. mansoni infection was observed among PSAC. Schistosomiasis control effort in such localities should include information, education, and communication, water, sanitation, and hygiene, and particularly chemotherapy targeting PSAC, reinforcing the need of the paediatric praziquantel formulation.
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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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10
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Wiegand RE, Secor WE, Fleming FM, French MD, King CH, Deol AK, Montgomery SP, Evans D, Utzinger J, Vounatsou P, de Vlas SJ. Associations between infection intensity categories and morbidity prevalence in school-age children are much stronger for Schistosoma haematobium than for S. mansoni. PLoS Negl Trop Dis 2021; 15:e0009444. [PMID: 34033646 PMCID: PMC8183985 DOI: 10.1371/journal.pntd.0009444] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 06/07/2021] [Accepted: 05/04/2021] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND World Health Organization (WHO) guidelines for measuring global progress in schistosomiasis control classify individuals with Schistosoma spp. infections based on the concentration of excreted eggs. We assessed the associations between WHO infection intensity categories and morbidity prevalence for selected S. haematobium and S. mansoni morbidities in school-age children. METHODOLOGY A total of 22,488 children aged 6-15 years from monitoring and evaluation cohorts in Burkina Faso, Mali, Niger, Uganda, Tanzania, and Zambia from 2003-2008 were analyzed using Bayesian logistic regression. Models were utilized to evaluate associations between intensity categories and the prevalence of any urinary bladder lesion, any upper urinary tract lesion, microhematuria, and pain while urinating (for S. haematobium) and irregular hepatic ultrasound image pattern (C-F), enlarged portal vein, laboratory-confirmed diarrhea, and self-reported diarrhea (for S. mansoni) across participants with infection and morbidity data. PRINCIPAL FINDINGS S. haematobium infection intensity categories possessed consistent morbidity prevalence across surveys for multiple morbidities and participants with light infections had elevated morbidity levels, compared to negative participants. Conversely, S. mansoni infection intensity categories lacked association with prevalence of the morbidity measures assessed. CONCLUSIONS/SIGNIFICANCE Current status infection intensity categories for S. haematobium were associated with morbidity levels in school-age children, suggesting urogenital schistosomiasis morbidity can be predicted by an individual's intensity category. Conversely, S. mansoni infection intensity categories were not consistently indicative of childhood morbidity at baseline or during the first two years of a preventive chemotherapy control program.
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Affiliation(s)
- Ryan E. Wiegand
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - W. Evan Secor
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | | | | | - Charles H. King
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Arminder K. Deol
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Susan P. Montgomery
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Darin Evans
- United States Agency for International Development, Washington DC, United States of America
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Penelope Vounatsou
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Sake J. de Vlas
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
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11
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Bärenbold O, Garba A, Colley DG, Fleming FM, Assaré RK, Tukahebwa EM, Kebede B, Coulibaly JT, N’Goran EK, Tchuem Tchuenté LA, Mwinzi P, Utzinger J, Vounatsou P. Estimating true prevalence of Schistosoma mansoni from population summary measures based on the Kato-Katz diagnostic technique. PLoS Negl Trop Dis 2021; 15:e0009310. [PMID: 33819266 PMCID: PMC8062092 DOI: 10.1371/journal.pntd.0009310] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 04/22/2021] [Accepted: 03/16/2021] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The prevalence of Schistosoma mansoni infection is usually assessed by the Kato-Katz diagnostic technique. However, Kato-Katz thick smears have low sensitivity, especially for light infections. Egg count models fitted on individual level data can adjust for the infection intensity-dependent sensitivity and estimate the 'true' prevalence in a population. However, application of these models is complex and there is a need for adjustments that can be done without modeling expertise. This study provides estimates of the 'true' S. mansoni prevalence from population summary measures of observed prevalence and infection intensity using extensive simulations parametrized with data from different settings in sub-Saharan Africa. METHODOLOGY An individual-level egg count model was applied to Kato-Katz data to determine the S. mansoni infection intensity-dependent sensitivity for various sampling schemes. Observations in populations with varying forces of transmission were simulated, using standard assumptions about the distribution of worms and their mating behavior. Summary measures such as the geometric mean infection, arithmetic mean infection, and the observed prevalence of the simulations were calculated, and parametric statistical models fitted to the summary measures for each sampling scheme. For validation, the simulation-based estimates are compared with an observational dataset not used to inform the simulation. PRINCIPAL FINDINGS Overall, the sensitivity of Kato-Katz in a population varies according to the mean infection intensity. Using a parametric model, which takes into account different sampling schemes varying from single Kato-Katz to triplicate slides over three days, both geometric and arithmetic mean infection intensities improve estimation of sensitivity. The relation between observed and 'true' prevalence is remarkably linear and triplicate slides per day on three consecutive days ensure close to perfect sensitivity. CONCLUSIONS/SIGNIFICANCE Estimation of 'true' S. mansoni prevalence is improved when taking into account geometric or arithmetic mean infection intensity in a population. We supply parametric functions and corresponding estimates of their parameters to calculate the 'true' prevalence for sampling schemes up to 3 days with triplicate Kato-Katz thick smears per day that allow estimation of the 'true' prevalence.
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Affiliation(s)
- Oliver Bärenbold
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Amadou Garba
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Daniel G. Colley
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
- Department of Microbiology, University of Georgia, Athens, Georgia, United States of America
| | - Fiona M. Fleming
- Schistosomiasis Control Initiative, Imperial College, London, United Kingdom
| | - Rufin K. Assaré
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
| | | | | | - Jean T. Coulibaly
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
| | - Eliézer K. N’Goran
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
| | - Louis-Albert Tchuem Tchuenté
- Laboratory of Parasitology and Ecology, University of Yaoundé I, Yaoundé, Cameroon
- Centre for Schistosomiasis and Parasitology, Yaoundé, Cameroon
| | - Pauline Mwinzi
- Centre for Global Health Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Penelope Vounatsou
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
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12
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Siqueira LMV, Senra C, de Oliveira ÁA, Carneiro NFDF, Gomes LI, Rabello A, Coelho PMZ, Oliveira E. A Real-Time PCR Assay for the Diagnosis of Intestinal Schistosomiasis and Cure Assessment After the Treatment of Individuals With Low Parasite Burden. Front Immunol 2021; 11:620417. [PMID: 33815351 PMCID: PMC8010660 DOI: 10.3389/fimmu.2020.620417] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 12/24/2020] [Indexed: 01/02/2023] Open
Abstract
The laboratorial diagnosis of the intestinal schistosomiasis is always performed using Kato-Katz technique. However, this technique presents low sensitivity for diagnosis of individuals with low parasite burden, which constitutes the majority in low endemicity Brazilian locations for the disease. The objective of this study was developed and to validate a real-time PCR assay (qPCR) targeting 121 bp sequence to detect Schistosoma spp. DNA for the diagnosis of intestinal schistosomiasis and a sequence of the human β-actin gene as internal control. Firstly, the qPCR was standardized and next it was evaluated for diagnosis and cure assessment of intestinal schistosomiasis in the resident individuals in Tabuas and Estreito de Miralta, two locations in Brazil endemic for intestinal schistosomiasis. The qPCR assay results were compared with those of the Kato-Katz (KK) test, examining 2 or 24 slides, Saline Gradient (SG) and “reference test” (24 KK slides + SG). The cure assessment was measured by these diagnostic techniques at 30, 90, and 180 days post-treatment. In Tabuas, the positivity rates obtained by the qPCR was 30.4% (45/148) and by “reference test” was of 31.0% (46/148), with no statistical difference (p = 0.91). The presumed cure rates at 30, 90, and 180 days post-treatment were 100, 94.4, and 78.4% by the analysis of 24 KK slides, 100, 94.4, and 78.4% by the SG, and 100, 83.3, and 62.1% by the qPCR assay. In Estreito de Miralta, the positivity obtained by qPCR was 18.3% (26/142) and with “reference test” was 24.6% (35/142), with no statistical difference (p = 0.20). The presumed cure rates were 93.3, 96.9, and 96.5% by the KK, 93.3, 96.9, and 100% by the SG, and 93.3, 93.9, and 96.5% by the qPCR at 30, 90, and 180 days post-treatment, respectively. This study showed that the diagnostic techniques presented different performance in the populations from the two districts (Tabuas and Estreito de Miralta) and reinforces the need of combining techniques to improve diagnosis accuracy, increasing the detection of individuals with low parasite burden. This combination of techniques consists an important strategy for controlling the disease transmission.
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Affiliation(s)
- Liliane Maria Vidal Siqueira
- Diagnosis and Therapy of Infectious and Oncologic Diseases, Instituto René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Brazil
| | - Carolina Senra
- Clinical Research and Public Politics in Infectious and Parasitic Diseases, Instituto René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Brazil
| | - Áureo Almeida de Oliveira
- Diagnosis and Therapy of Infectious and Oncologic Diseases, Instituto René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Brazil
| | | | - Luciana Inácia Gomes
- Clinical Research and Public Politics in Infectious and Parasitic Diseases, Instituto René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Brazil
| | - Ana Rabello
- Clinical Research and Public Politics in Infectious and Parasitic Diseases, Instituto René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Brazil
| | - Paulo Marcos Zech Coelho
- Diagnosis and Therapy of Infectious and Oncologic Diseases, Instituto René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Brazil
| | - Edward Oliveira
- Clinical Research and Public Politics in Infectious and Parasitic Diseases, Instituto René Rachou, Oswaldo Cruz Foundation, Belo Horizonte, Brazil
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13
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Shen Y, Ji R, Chai R, Yuan N, Zhang J, Jing Y, Yang M, Zhang L, Hong Y, Lin J, Zhu C. A novel fluorescence immunochromatographic assay strip for the diagnosis of schistosomiasis japonica. Parasit Vectors 2021; 14:8. [PMID: 33407752 PMCID: PMC7788720 DOI: 10.1186/s13071-020-04511-6] [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: 11/08/2019] [Accepted: 12/01/2020] [Indexed: 11/18/2022] Open
Abstract
Background Schistosomiasis japonica is a severe zoonosis. Domestic animals are the primary source of infection and play an important role in disease transmission. Surveillance and diagnosis play key roles in schistosomiasis control; however, current techniques for the surveillance and diagnosis of the disease have limitations. In this study, we developed a novel fluorescence immunochromatographic assay (FICA) strip to detect anti-Schistosoma japonicum antibodies in host serum. Methods A FICA strip was developed for the diagnosis of Schistosoma japonicum in domestic animals. Streptococcus protein G (SPG) and soluble egg antigen (SEA) were transferred onto a nitrocellulose (NC) membrane to form the control line (C) and the test line (T), respectively. With fluorescence activity as well as binding activity to multispecies IgG, the recombinant protein rSPG-RFP was expressed and employed as an antibody indicator in the FICA strips. Results The dual gene fusion plasmid was verified by PCR and restriction enzyme digestion. The expressed recombinant protein was 39.72 kDa in size, which was consistent with the predicted molecular weight. The western blot results showed binding activity between rSPG-RFP and IgGs from different hosts. Fluorescence microscopy also showed the fluorescence activity of the protein present. The affinity constant (Ka) values of rSPG-RFP with rabbit, donkey, mouse and goat IgG were 1.9 × 105, 4.1 × 105, 1.7 × 105 and 5.4 × 105, respectively. Moreover, based on the recombinant protein, the test strip for detecting S. japonicum in buffaloes could distinguish positive from negative serum. The lower limit of detection of the FICA strip was 1:10,000. Compared with ELISA, the FICA strips exhibited similar results in the diagnosis of infection in clinical bovine serum samples, with a kappa value of 0.9660 and P < 0.01. The cross-reactivities of the FICA strips with Haemonchus contortus and Schistosoma turkestanicum (30.15% and 91.66%, respectively) were higher than those of ELISA (26.98% and 87.5%, respectively). Conclusions Based on the rSPG-RFP protein that we developed, strip detection can be completed within 15 min. Heightened sensitivity allows the strip to accurately identify schistosome antibodies in serum. In conclusion, this method is convenient, feasible, rapid and effective for detecting S. japonicum.![]()
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Affiliation(s)
- Yuanxi Shen
- Key Laboratory of Animal Parasitology, Ministry of Agriculture of China, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Rongyi Ji
- Key Laboratory of Animal Parasitology, Ministry of Agriculture of China, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Rui Chai
- Key Laboratory of Animal Parasitology, Ministry of Agriculture of China, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Nana Yuan
- Key Laboratory of Animal Parasitology, Ministry of Agriculture of China, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Jiyue Zhang
- Key Laboratory of Animal Parasitology, Ministry of Agriculture of China, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Yi Jing
- Key Laboratory of Animal Parasitology, Ministry of Agriculture of China, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Man Yang
- Key Laboratory of Animal Parasitology, Ministry of Agriculture of China, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Lanqi Zhang
- Key Laboratory of Animal Parasitology, Ministry of Agriculture of China, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China.,University of Reading, Whiteknights, Reading, Berkshire, RG26UA, England
| | - Yang Hong
- Key Laboratory of Animal Parasitology, Ministry of Agriculture of China, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Jiaojiao Lin
- Key Laboratory of Animal Parasitology, Ministry of Agriculture of China, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
| | - Chuangang Zhu
- Key Laboratory of Animal Parasitology, Ministry of Agriculture of China, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China.
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14
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Ndassi VD, Anchang-Kimbi JK, Sumbele IUN, Ngufor LA, Nadege K, Kimbi HK. The epidemiological status of urogenital schistosomiasis among reproductive aged individuals in the Tiko Health Area- a semi-urban setting in the Mount Cameroon area. PLoS Negl Trop Dis 2021; 15:e0008978. [PMID: 33428614 PMCID: PMC7822554 DOI: 10.1371/journal.pntd.0008978] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 01/22/2021] [Accepted: 11/11/2020] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Urogenital schistosomiasis (UGS) caused by S. haematobium has enormous reproductive health consequences including infertility. Reproductive aged individuals are a neglected group and not included in control programs in Cameroon. This study investigated the prevalence and severity of S. haematobium infection in the context of gender and socio-economic structures that shape behaviour among reproductive aged individuals living in Tiko, a semi-urban setting, Cameroon. METHODOLOGY/PRINCIPAL FINDINGS A cross-sectional study was carried out in the Tiko Health District (THD) between May to September 2019. Consenting individuals were enrolled using a convenient sampling technique and administered a semi-structured questionnaire to document data on socio-demographic and stream contact behaviour. A urine sample was collected and screened for the presence of S. haematobium ova using reagent strips, filtration and microscopy. The overall prevalence of S. haematobium infection was 22.8% (95% CL: 19.27-26.73) with geometric mean egg load of 18.74 (range: 1-1600) per 10ml of urine. Younger age group (15 - 20years) (OR: 5.13; 95% CL: 1.35-19.42), male (OR: 2.60 3.07; 95% CL: 1.54-4.40) and awareness of UGS (OR: 1.73; 95% CL: 1.02-2.95) were associated with higher odds of exposure to infection. Significantly higher intensity of infection was seen in males, singles and in the age group 15-30 years. It is worth noting that males carried out more activities which entailed longer duration in streams. CONCLUSION/SIGNIFICANCE The prevalence obtained shows that Tiko is a moderate-risk area for UGS with underlying morbidity-inducing infection intensity. The severity of the infection is more in males. Awareness of the disease is not enough to protect these communities from infection, but provision of public infrastructures and health education will limit contact with infested water and thus curtail the infection. There is an urgent need to involve all age groups in control programs.
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Affiliation(s)
- Vicky Daonyle Ndassi
- Department of Zoology and Animal Physiology, Faculty of Science, University of Buea, Buea, Cameroon
| | | | - Irene Ule Ngole Sumbele
- Department of Zoology and Animal Physiology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Lennin Azaofah Ngufor
- Department of Zoology and Animal Physiology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Kouemou Nadege
- Department of Zoology and Animal Physiology, Faculty of Science, University of Buea, Buea, Cameroon
| | - Helen Kuokuo Kimbi
- Department of Zoology and Animal Physiology, Faculty of Science, University of Buea, Buea, Cameroon
- Department of Medical Laboratory Science, Faculty of Health Sciences, University of Bamenda, Bamenda, Cameroon
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15
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Huang Y, Wu Q, Zhao L, Xiong C, Xu Y, Dong X, Wen Y, Cao J. UHPLC-MS-Based Metabolomics Analysis Reveals the Process of Schistosomiasis in Mice. Front Microbiol 2020; 11:1517. [PMID: 32760365 PMCID: PMC7371968 DOI: 10.3389/fmicb.2020.01517] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 06/11/2020] [Indexed: 12/13/2022] Open
Abstract
Metabolomics, as an emerging technology, has been demonstrated to be a very powerful tool in the study of the host metabolic responses to infections by parasites. Schistosomiasis is a parasitic infection caused by schistosoma worm via the direct contact with the water containing cercaria, among which Schistosoma japonicum (S. japonicum) is endemic in Asia. In order to characterize the schistosome-induced changes in the host metabolism and further to develop the strategy for early diagnosis of schistosomiasis, we performed comprehensive LC-MS-based metabolomics analysis of serum from mice infected by S. japonicum for 5 weeks. With the developed diagnosis strategy based on our metabolomics data, we were able to successfully detect schistosomiasis at the first week post-infection, which was 3 weeks earlier than "gold standard" methods and 2 weeks earlier than the methods based on 1H NMR spectroscopy. Our metabolomics study revealed that S. japonicum infection induced the metabolic changes involved in a variety of metabolic pathways including amino acid metabolism, DNA and RNA biosynthesis, phospholipid metabolism, depression of energy metabolism, glucose uptake and metabolism, and disruption of gut microbiota metabolism. In addition, we identified seventeen specific metabolites whose down-regulated profiles were closely correlated with the time-course of schistosomiasis progression and can also be used as an indicator for the worm-burdens. Interestingly, the decrease of these seventeen metabolites was particularly remarkable at the first week post-infection. Thus, our findings on mechanisms of host-parasite interaction during the disease process pave the way for the development of an early diagnosis tool and provide more insightful understandings of the potential metabolic process associated with schistosomiasis in mice. Furthermore, the diagnosis strategy developed in this work is cost-effective and is superior to other currently used diagnosis methods.
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Affiliation(s)
- Yuzheng Huang
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, China
- Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
- Public Health Research Center, Jiangnan University, Wuxi, China
| | - Qiong Wu
- Department of Pharmacy, General Hospital of Southern Theater Command, Guangzhou, China
| | - Liang Zhao
- Bloomberg-Kimmel Institute for Cancer Immunotherapy, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD, United States
| | - Chunrong Xiong
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, China
- Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
- Public Health Research Center, Jiangnan University, Wuxi, China
| | - Yongliang Xu
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, China
- Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
- Public Health Research Center, Jiangnan University, Wuxi, China
| | - Xin Dong
- School of Medicine, Shanghai University, Shanghai, China
- Institute of Translation Medicine, Shanghai University, Shanghai, China
| | - Yan Wen
- Department of Pharmacy, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Jun Cao
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, China
- Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
- Public Health Research Center, Jiangnan University, Wuxi, China
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16
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Accuracy of real-time polymerase chain reaction to detect Schistosoma mansoni - infected individuals from an endemic area with low parasite loads. Parasitology 2020; 147:1140-1148. [PMID: 32484122 DOI: 10.1017/s003118202000089x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Due to the efforts to control schistosomiasis transmission in tropical countries, a large proportion of individuals from endemic areas present low parasite loads, which hinders diagnosis of intestinal schistosomiasis by the Kato-Katz (KK) method. Therefore, the development of more sensitive diagnostic methods is essential for efficient control measures. The aim was to evaluate the accuracy of a real-time polymerase chain reaction (RT-PCR) to detect Schistosoma mansoni DNA in fecal samples of individuals with low parasite loads. A cross-sectional population-based study was conducted in a rural community (n = 257) in Brazil. POC-CCA® was performed in urine and feces were used for RT-PCR. In addition, fecal exams were completed by 18 KK slides, saline gradient and Helmintex techniques. The combined results of the three parasitological tests detected schistosome eggs in 118 participants (45.9%) and composed the consolidated reference standard (CRS). By RT-PCR, 117 out of 215 tested samples were positive, showing 91.4% sensitivity, 80.2% specificity and good concordance with the CRS (kappa = 0.71). RT-PCR identified 86.9% of the individuals eliminating less than 12 eggs/g of feces, demonstrating much better performance than POC-CCA® (50.8%). Our results showed that RT-PCR is a valuable alternative for the diagnosis of intestinal schistosomiasis in individuals with very low parasite loads.
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17
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Hoekstra PT, Casacuberta-Partal M, van Lieshout L, Corstjens PLAM, Tsonaka R, Assaré RK, Silué KD, Meité A, N’Goran EK, N’Gbesso YK, Amoah AS, Roestenberg M, Knopp S, Utzinger J, Coulibaly JT, van Dam GJ. Efficacy of single versus four repeated doses of praziquantel against Schistosoma mansoni infection in school-aged children from Côte d'Ivoire based on Kato-Katz and POC-CCA: An open-label, randomised controlled trial (RePST). PLoS Negl Trop Dis 2020; 14:e0008189. [PMID: 32196506 PMCID: PMC7112237 DOI: 10.1371/journal.pntd.0008189] [Citation(s) in RCA: 10] [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: 12/13/2019] [Revised: 04/01/2020] [Accepted: 03/02/2020] [Indexed: 11/21/2022] Open
Abstract
Background Preventive chemotherapy with praziquantel (PZQ) is the cornerstone of schistosomiasis control. However, a single dose of PZQ (40 mg/kg) does not cure all infections. Repeated doses of PZQ at short intervals might increase efficacy in terms of cure rate (CR) and intensity reduction rate (IRR). Here, we determined the efficacy of a single versus four repeated treatments with PZQ on Schistosoma mansoni infection in school-aged children from Côte d’Ivoire, using two different diagnostic tests. Methods An open-label, randomized controlled trial was conducted from October 2018 to January 2019. School-aged children with a confirmed S. mansoni infection based on Kato-Katz (KK) and point-of-care circulating cathodic antigen (POC-CCA) urine cassette test were randomly assigned to receive either a single or four repeated doses of PZQ, administered at two-week intervals. The primary outcome was the difference in CR between the two treatment arms, measured by triplicate KK thick smears 10 weeks after the first treatment. Secondary outcomes included CR estimated by POC-CCA, IRR by KK and POC-CCA, and safety of repeated PZQ administration. Principal findings During baseline screening, 1,022 children were assessed for eligibility of whom 153 (15%) had a detectable S. mansoni infection, and hence, were randomized to the standard treatment group (N = 70) and the intense treatment group (N = 83). Based on KK, the CR was 42% (95% confidence interval (CI) 31–52%) in the standard treatment group and 86% (95% CI 75–92%) in the intense treatment group. Observed IRR was 72% (95% CI 55–83%) in the standard treatment group and 95% (95% CI 85–98%) in the intense treatment group. The CR estimated by POC-CCA was 18% (95% CI 11–27%) and 36% (95% CI 26–46%) in the standard and intense treatment group, respectively. Repeated PZQ treatment did not result in a higher number of adverse events. Conclusion/significance The observed CR using KK was significantly higher after four repeated treatments compared to a single treatment, without an increase in adverse events. Using POC-CCA, the observed CR was significantly lower than measured by KK, indicating that PZQ may be considerably less efficacious as concluded by KK. Our findings highlight the need for reliable and more accurate diagnostic tools, which are essential for monitoring treatment efficacy, identifying changes in transmission, and accurately quantifying the intensity of infection in distinct populations. In addition, the higher CR in the intense treatment group suggests that more focused and intense PZQ treatment can help to advance schistosomiasis control. Trial registration www.clinicaltrials.govNCT02868385. The previously established efficacy of the widely used drug praziquantel (PZQ) against schistosomiasis might have been overestimated due to the use of inaccurate diagnostic methods. Repeated PZQ treatment at short intervals in areas with ongoing transmission could more effectively target non-susceptible schistosomula as they will have matured into drug susceptible worms within a few weeks. In the current study, we aimed to determine the cure rate (CR) of repeated PZQ, measured by the Kato-Katz (KK) technique and the point-of-care circulating cathodic antigen (POC-CCA) test, respectively. An open-label, randomized controlled trial was conducted assigning 153 school-aged children with a confirmed Schistosoma mansoni infection to two groups, one receiving a single PZQ treatment, while the second group received four repeated PZQ treatments, given at two-week intervals. Based on the KK test, the CR was significantly higher after four repeated treatments compared to a single treatment. When using POC-CCA, a diagnostic method that has not been utilized before in studies assessing the efficacy of four repeated PZQ treatments, the CR was much lower, even after four repeated PZQ treatments. Our results indicate that worms are still present after multiple PZQ treatments and that PZQ might be less efficacious than previously published.
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Affiliation(s)
- Pytsje T. Hoekstra
- Department of Parasitology, Leiden University Medical Center, Leiden, the Netherlands
- * E-mail:
| | | | - Lisette van Lieshout
- Department of Parasitology, Leiden University Medical Center, Leiden, the Netherlands
| | - Paul L. A. M. Corstjens
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - Roula Tsonaka
- Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, the Netherlands
| | - Rufin K. Assaré
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Kigbafori D. Silué
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
| | - Aboulaye Meité
- Programme National de Lutte contre les Maladies Tropicales Négligées à Chimiothérapie Préventive, Ministère de la Santé et de l’Hygiène Publique, Abidjan, Côte d’Ivoire
| | - Eliézer K. N’Goran
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
| | - Yves K. N’Gbesso
- Département d’Agboville, Centre de Santé Urbain d’Azaguié, Azaguié, Côte d’Ivoire
| | - Abena S. Amoah
- Department of Parasitology, Leiden University Medical Center, Leiden, the Netherlands
- Department of Population Health, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Malawi Epidemiology and Intervention Research Unit, Chilumba, Karonge District, Malawi
| | - Meta Roestenberg
- Department of Parasitology, Leiden University Medical Center, Leiden, the Netherlands
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, the Netherlands
| | - Stefanie Knopp
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Jean T. Coulibaly
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Govert J. van Dam
- Department of Parasitology, Leiden University Medical Center, Leiden, the Netherlands
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Noah NM, Ndangili PM. Current Trends of Nanobiosensors for Point-of-Care Diagnostics. JOURNAL OF ANALYTICAL METHODS IN CHEMISTRY 2019; 2019:2179718. [PMID: 31886019 PMCID: PMC6925704 DOI: 10.1155/2019/2179718] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 09/03/2019] [Accepted: 09/28/2019] [Indexed: 05/24/2023]
Abstract
In order to provide better-quality health care, it is very important that high standards of health care management are achieved by making timely decisions based on rapid diagnostics, smart data analysis, and informatics analysis. Point-of-care testing ensures fast detection of analytes near to the patients facilitating a better disease diagnosis, monitoring, and management. It also enables quick medical decisions since the diseases can be diagnosed at an early stage which leads to improved health outcomes for the patients enabling them to start early treatment. In the recent past, various potential point-of-care devices have been developed and they are paving the way to next-generation point-of-care testing. Biosensors are very critical components of point-of-care devices since they are directly responsible for the bioanalytical performance of an essay. As such, they have been explored for their prospective point-of-care applications necessary for personalized health care management since they usually estimate the levels of biological markers or any chemical reaction by producing signals mainly associated with the concentration of an analyte and hence can detect disease causing markers such as body fluids. Their high selectivity and sensitivity have allowed for early diagnosis and management of targeted diseases; hence, facilitating timely therapy decisions and combination with nanotechnology can improve assessment of the disease onset and its progression and help to plan for treatment of many diseases. In this review, we explore how nanotechnology has been utilized in the development of nanosensors and the current trends of these nanosensors for point-of-care diagnosis of various diseases.
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Affiliation(s)
- Naumih M. Noah
- School of Pharmacy and Health Sciences, United States International University-Africa, P.O. Box 14634-00800, Nairobi, Kenya
| | - Peter M. Ndangili
- Department of Chemical Science and Technology (DCST), Technical University of Kenya, P.O. Box 52428-00200, Nairobi, Kenya
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19
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Neves MI, Webster JP, Walker M. Estimating helminth burdens using sibship reconstruction. Parasit Vectors 2019; 12:441. [PMID: 31522688 PMCID: PMC6745796 DOI: 10.1186/s13071-019-3687-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 08/28/2019] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Sibship reconstruction is a form of parentage analysis that can be used to identify the number of helminth parental genotypes infecting individual hosts using genetic data on only their offspring. This has the potential to be used for estimating individual worm burdens when adult parasites are otherwise inaccessible, the case for many of the most globally important human helminthiases and neglected tropical diseases. Yet methods of inferring worm burdens from sibship reconstruction data on numbers of unique parental genotypes are lacking, limiting the method's scope of application. RESULTS We developed a novel statistical method for estimating female worm burdens from data on the number of unique female parental genotypes derived from sibship reconstruction. We illustrate the approach using genotypic data on Schistosoma mansoni (miracidial) offspring collected from schoolchildren in Tanzania. We show how the bias and precision of worm burden estimates critically depends on the number of sampled offspring and we discuss strategies for obtaining sufficient sample sizes and for incorporating judiciously formulated prior information to improve the accuracy of estimates. CONCLUSIONS This work provides a novel approach for estimating individual-level worm burdens using genetic data on helminth offspring. This represents a step towards a wider scope of application of parentage analysis techniques. We discuss how the method could be used to assist in the interpretation of monitoring and evaluation data collected during mass drug administration programmes targeting human helminthiases and to help resolve outstanding questions on key population biological processes that govern the transmission dynamics of these neglected tropical diseases.
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Affiliation(s)
- M Inês Neves
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hawkshead Lane, Hatfield, UK. .,London Centre for Neglected Tropical Disease Research, London, UK.
| | - Joanne P Webster
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hawkshead Lane, Hatfield, UK.,London Centre for Neglected Tropical Disease Research, London, UK
| | - Martin Walker
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hawkshead Lane, Hatfield, UK.,London Centre for Neglected Tropical Disease Research, London, UK
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20
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Schistosoma japonicum cathepsin B as potential diagnostic antigen for Asian zoonotic schistosomiasis. Parasitol Res 2019; 118:2601-2608. [PMID: 31377909 DOI: 10.1007/s00436-019-06410-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 07/25/2019] [Indexed: 02/02/2023]
Abstract
In this study, the diagnostic value of Schistosoma japonicum cathepsin B (SjCatB) was evaluated as an antigen for the early detection of S. japonicum infection. SjCatB is a key protease used by the cercaria to penetrate the intact skin of the host for transdermal infection. The early exposure of the host's immune system to this enzyme may elicit early production of antibodies against this molecule. Therefore, the recombinant SjCatB (rSjCatB) was expressed in Escherichia coli with N-terminal 6xHis-tag. rSjCatB was tested for its performance as a diagnostic antigen using indirect enzyme-linked immunosorbent assay (ELISA) with sera from experimentally infected mice collected at > 8 weeks post-infection. Showing 100% sensitivity and 95.0% specificity in the ELISA, rSjCatB was then evaluated with sera from experimentally infected mice collected at 1-7 weeks post-infection to determine how early the antibodies can be detected. Results showed that as early as 6 weeks post-infection, 2 of the 3 infected mice were found to be positive with the antibodies against SjCatB. Furthermore, the potential of the recombinant antigen in detecting human schistosomiasis was evaluated with archived serum samples collected from individuals who had been diagnosed with S. japonicum infection by stool examination. Results showed 86.7% sensitivity and 96.7% specificity suggesting its high diagnostic potential for human schistosomiasis. In addition, SjCatB showed minimal cross-reaction with the sera collected from patients with other parasitic diseases. In conclusion, the results of this study suggest that SjCatB will be useful in the development of a sensitive and specific early detection test for S. japonicum infection.
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21
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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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22
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de Sousa SRM, Dias IHL, Fonseca ÁLS, Contente BR, Nogueira JFC, da Costa Oliveira TN, Geiger SM, Enk MJ. Concordance of the point-of-care circulating cathodic antigen test for the diagnosis of intestinal schistosomiasis in a low endemicity area. Infect Dis Poverty 2019; 8:37. [PMID: 31142379 PMCID: PMC6542115 DOI: 10.1186/s40249-019-0551-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 05/16/2019] [Indexed: 11/25/2022] Open
Abstract
Background The Kato-Katz technique is recommended worldwide for the diagnosis of intestinal schistosomiasis, detecting parasite eggs in feces of infected people. However, new tests have been developed in order to facilitate diagnosis, e.g. by detection of specific antigens secreted by schistosomes, such as the circulating cathodic antigen (CCA). The aim of this study was to evaluate the performance of the point-of-care circulating cathodic antigen test (POC-CCA) compared to the Kato-Katz technique in a low prevalence area in the Amazon Region, located in the municipality of Primavera, State of Pará, Brazil. Methods Positivity rates of the POC-CCA test and the Kato-Katz technique were calculated. The sensitivity, specificity, accuracy and kappa coefficient were determined by comparing both methods. The reference standard was established using 16 Kato-Katz slides, 12 of the first fecal sample, two of the second and two of the third one. The study also included the concordance between POC-CCA results and different numbers and combinations of Kato-Katz slides. Results The prevalence of schistosomiasis according to the reference standard or POC-CCA test reached a rate of 9.4% or 23.9%, respectively, among a total of 372 participants. The positivity rates by the Kato-Katz technique increased from 2.4 to 9.4%, according to the increase in the number of slides examined and fecal samples collected. A sensitivity of 55.6%, specificity 76.9%, accuracy 76% and κ coefficient of 0.06 was observed by comparing one slide of the first sample and POC-CCA. Comparing 6 slides from three different samples, two slides of each, with POC-CCA resulted in a sensitivity of 58.3%, specificity 78.4%, accuracy 77% and κ coefficient of 0.16. Finally, the comparison of 16 slides from three different samples with POC-CCA revealed a sensitivity of 65.7%, specificity 80.4%, accuracy 79%, and κ coefficient of 0.27. Conclusions The immunochromatographic test has the potential to be an important tool to combat schistosomiasis because of its practicality and applicability but should be applied with caution in low prevalence areas and in programs that aim to eliminate this disease. Trial registration CAAE#21824513.9.0000.5091. January 31st, 2014. Electronic supplementary material The online version of this article (10.1186/s40249-019-0551-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sergei Rodrigo Magalhães de Sousa
- Programa de Pós-Graduação Strictu Sensu em Biologia Parasitária na Amazônia da Universidade do Estado do Pará, Tv. Perebebuí, 2623 - Marco, Belém, PA, 66087, Brazil. .,Laboratório de Parasitoses Intestinais, Esquistossomose e Malacologia (LPIEM), Secção de Parasitologia, Instituto Evandro Chagas/SVS/MS, Ananindeua, Pará, Brazil.
| | - Isabelle Helena Lima Dias
- Programa de Pós-Graduação Strictu Sensu em Biologia Parasitária na Amazônia da Universidade do Estado do Pará, Tv. Perebebuí, 2623 - Marco, Belém, PA, 66087, Brazil.,Laboratório de Parasitoses Intestinais, Esquistossomose e Malacologia (LPIEM), Secção de Parasitologia, Instituto Evandro Chagas/SVS/MS, Ananindeua, Pará, Brazil
| | - Álvaro Luan Santana Fonseca
- Programa de Pós-Graduação Strictu Sensu em Biologia Parasitária na Amazônia da Universidade do Estado do Pará, Tv. Perebebuí, 2623 - Marco, Belém, PA, 66087, Brazil.,Laboratório de Parasitoses Intestinais, Esquistossomose e Malacologia (LPIEM), Secção de Parasitologia, Instituto Evandro Chagas/SVS/MS, Ananindeua, Pará, Brazil
| | - Bianca Rodrigues Contente
- Programa de Pós-Graduação Strictu Sensu em Biologia Parasitária na Amazônia da Universidade do Estado do Pará, Tv. Perebebuí, 2623 - Marco, Belém, PA, 66087, Brazil.,Laboratório de Parasitoses Intestinais, Esquistossomose e Malacologia (LPIEM), Secção de Parasitologia, Instituto Evandro Chagas/SVS/MS, Ananindeua, Pará, Brazil
| | - Joyce Favacho Cardoso Nogueira
- Programa de Pós-Graduação Strictu Sensu em Biologia Parasitária na Amazônia da Universidade do Estado do Pará, Tv. Perebebuí, 2623 - Marco, Belém, PA, 66087, Brazil.,Laboratório de Parasitoses Intestinais, Esquistossomose e Malacologia (LPIEM), Secção de Parasitologia, Instituto Evandro Chagas/SVS/MS, Ananindeua, Pará, Brazil
| | - Tatyellen Natasha da Costa Oliveira
- Programa de Pós-Graduação Strictu Sensu em Biologia Parasitária na Amazônia da Universidade do Estado do Pará, Tv. Perebebuí, 2623 - Marco, Belém, PA, 66087, Brazil
| | - Stefan Michael Geiger
- Departamento de Parasitologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Martin Johannes Enk
- Programa de Pós-Graduação Strictu Sensu em Biologia Parasitária na Amazônia da Universidade do Estado do Pará, Tv. Perebebuí, 2623 - Marco, Belém, PA, 66087, Brazil.,Laboratório de Parasitoses Intestinais, Esquistossomose e Malacologia (LPIEM), Secção de Parasitologia, Instituto Evandro Chagas/SVS/MS, Ananindeua, Pará, Brazil
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23
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Rujeni N, Mazimpaka A, Tumusiime M, Nyandwi E, Rutayisire G, Kayiranga P, Umulisa I, Ruberanziza E, Osier F, Mutapi F. Pre-school aged children are exposed to Schistosoma through Lake Kivu in Rwanda. AAS Open Res 2019; 2:7. [DOI: 10.12688/aasopenres.12930.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/14/2019] [Indexed: 12/24/2022] Open
Abstract
Background: Schistosomiasis is prevalent in many sub-Saharan African countries and transmission is through waters contaminated by infected snails. In Rwanda, although schistosomiasis is endemic, very few epidemiological studies exist; of these, schoolchildren have been the focus, neglecting pre-school-aged children (PSAC). Furthermore, malacological surveys to indicate the potential for transmission are scarce in the country. The aim of this study was to determine the prevalence of schistosomiasis among PSAC living on Nkombo Island in Lake Kivu and to map the distribution and infectivity of snails in the area. Methods: Stool and urine samples were collected from children aged 1 to 4 years and tested for schistosomiasis using the Kato Katz and the point-of-care circulating cathodic antigen (POC-CCA) diagnostic techniques respectively. Snails were collected along the shores at five different locations with human-water contact activities and cercaria shedding was microscopically examined. GPS receivers were used to collect geographical coordinates and snail distribution maps were generated using ArcGIS. A questionnaire was used to assess water contact activities and frequency. Results: A total of 278 PSAC were recruited. Overall, 9.5% (excluding traces) of the tested children reacted positively to the POC-CCA, although there were no ova detected in their stool via Kato Katz. The questionnaire revealed that 48.2% of parents/guardians use Lake Kivu’s water for household activities while 42.4% children are taken to the Lake shores daily. Overall, 13.5% of collected snails shed cercariae. Conclusions: PSAC of Nkombo Island are exposed to Schistosoma parasites through contact with Lake Kivu, which hosts a number of snails shedding cercaria. Exposure is through recreational activities but also through bathing as safe water is scarce in the area. Health education of parents/guardians of these young children should be promoted and the national schistosomiasis control program should be integrated into water supply projects.
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Rubaba O, Chimbari MJ, Soko W, Manyangadze T, Mukaratirwa S. Validation of a urine circulating cathodic antigen cassette test for detection of Schistosoma haematobiumin uMkhanyakude district of South Africa. Acta Trop 2018; 182:161-165. [PMID: 29486172 DOI: 10.1016/j.actatropica.2018.02.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 01/18/2018] [Accepted: 02/23/2018] [Indexed: 01/06/2023]
Abstract
Circulating cathodic antigen (CCA) tests for schistosomiasis are fast and less complicated allowing making them good candidates for routine qualitative screening for schistosomiasis at point of care. The urine-CCA has been evaluated for detection of S. mansoni with promising results. Its specificity and consistency in detecting S. haematobium infection in different endemic regions has been variable. This study validated a rapid urine-CCA cassette test for qualitative detection of S. haematobium infection in an S. haematobium endemic area with low S. mansoni prevalence. Microscopic examination for the standard urine filtration technique was used to validate the commercially available urine-CCA cassette test (rapid medical diagnostics ®). The validation was done in a sample of primary school pupils (n = 420) aged 10-15 years in schools in the Jozini Municipality, KZN. There was a relationship between infection intensity and a positive urine-CCA test. Using the urine filtration method as the gold standard, the prevalence for S. haematobium was 40%, the accuracy of the CCA kit was 54.8%, sensitivity was 68.1% while the specificity was 45.8%. The positive predictive value was 45.82% while the negative predictive value was 68.05%. Both the urine filtration and the urine-CCA methods detected heavy (≥50 eggs/10 mL urine) and light infections at statistically significant levels. The overall accuracy, sensitivity and specificity of the urine-CCA cassette test were low. The urine-CCA cassette test performed much better for heavy infections than low infections (p < 0.05) implying that the kit may not be suitable for low endemic areas.
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Affiliation(s)
- O Rubaba
- School of Nursing and Public Health, College of Health Science, University of KwaZulu-Natal, Durban, South Africa.
| | - M J Chimbari
- School of Nursing and Public Health, College of Health Science, University of KwaZulu-Natal, Durban, South Africa
| | - W Soko
- School of Nursing and Public Health, College of Health Science, University of KwaZulu-Natal, Durban, South Africa
| | - T Manyangadze
- School of Nursing and Public Health, College of Health Science, University of KwaZulu-Natal, Durban, South Africa
| | - S Mukaratirwa
- School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
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Lindholz CG, Favero V, Verissimo CDM, Candido RRF, de Souza RP, dos Santos RR, Morassutti AL, Bittencourt HR, Jones MK, St. Pierre TG, Graeff-Teixeira C. Study of diagnostic accuracy of Helmintex, Kato-Katz, and POC-CCA methods for diagnosing intestinal schistosomiasis in Candeal, a low intensity transmission area in northeastern Brazil. PLoS Negl Trop Dis 2018; 12:e0006274. [PMID: 29518081 PMCID: PMC5843168 DOI: 10.1371/journal.pntd.0006274] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 01/26/2018] [Indexed: 11/19/2022] Open
Abstract
Control initiatives have successfully reduced the prevalence and intensity of schistosomiasis transmission in several localities around the world. However, individuals that release low numbers of eggs in their feces may not be detected by classical methods that are limited by low sensitivity. Given that accurate estimates of prevalence are key to implementing planning control actions for the elimination of schistosomiasis, new diagnostic tools are needed to effectively monitor infections and confirm transmission interruption. The World Health Organization recommends the Kato-Katz (KK) thick smear as a parasitological test for epidemiological surveys, even though this method has been demonstrated to underestimate prevalence when egg burdens are low. The point-of-care immunodiagnostic for detecting schistosome cathodic circulating antigen (POC-CCA) method has been proposed as a more sensitive substitute for KK in prevalence estimations. An alternative diagnostic, the Helmintex (HTX) method, isolates eggs from fecal samples with the use of paramagnetic particles in a magnetic field. Here, a population-based study involving 461 individuals from Candeal, Sergipe State, Brazil, was conducted to evaluate these three methods comparatively by latent class analysis (LCA). The prevalence of schistosomiasis mansoni was determined to be 71% with POC-CCA, 40.% with HTX and 11% with KK. Most of the egg burdens of the individuals tested (70%) were < 1 epg, thereby revealing a dissociation between prevalence and intensity in this locality. Therefore, the present results confirm that the HTX method is a highly sensitive egg detection procedure and support its use as a reference method for diagnosing intestinal schistosomiasis and for comparative evaluation of other tests.
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Affiliation(s)
- Catieli Gobetti Lindholz
- Laboratório de Biologia Parasitária, School of Sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Vivian Favero
- Laboratório de Biologia Parasitária, School of Sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Carolina de Marco Verissimo
- Laboratório de Biologia Parasitária, School of Sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
- School of Biological Sciences, Queen’s University Belfast, Belfast, Northern Ireland
| | | | - Renata Perotto de Souza
- Laboratório de Biologia Parasitária, School of Sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Renata Rosa dos Santos
- Laboratório de Biologia Parasitária, School of Sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Alessandra Loureiro Morassutti
- Laboratório de Biologia Parasitária, School of Sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Helio Radke Bittencourt
- Polytechnic School, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Malcolm K. Jones
- School of Veterinary Science, The University of Queensland, Queensland, Australia
| | - Timothy G. St. Pierre
- School of Physics, The University of Western Australia, Crawley, Western Australia, Australia
| | - Carlos Graeff-Teixeira
- Laboratório de Biologia Parasitária, School of Sciences, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
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Rosa BA, Supali T, Gankpala L, Djuardi Y, Sartono E, Zhou Y, Fischer K, Martin J, Tyagi R, Bolay FK, Fischer PU, Yazdanbakhsh M, Mitreva M. Differential human gut microbiome assemblages during soil-transmitted helminth infections in Indonesia and Liberia. MICROBIOME 2018; 6:33. [PMID: 29486796 PMCID: PMC6389212 DOI: 10.1186/s40168-018-0416-5] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 01/26/2018] [Indexed: 05/11/2023]
Abstract
BACKGROUND The human intestine and its microbiota is the most common infection site for soil-transmitted helminths (STHs), which affect the well-being of ~ 1.5 billion people worldwide. The complex cross-kingdom interactions are not well understood. RESULTS A cross-sectional analysis identified conserved microbial signatures positively or negatively associated with STH infections across Liberia and Indonesia, and longitudinal samples analysis from a double-blind randomized trial showed that the gut microbiota responds to deworming but does not transition closer to the uninfected state. The microbiomes of individuals able to self-clear the infection had more alike microbiome assemblages compared to individuals who remained infected. One bacterial taxon (Lachnospiracae) was negatively associated with infection in both countries, and 12 bacterial taxa were significantly associated with STH infection in both countries, including Olsenella (associated with reduced gut inflammation), which also significantly reduced in abundance following clearance of infection. Microbial community gene abundances were also affected by deworming. Functional categories identified as associated with STH infection included arachidonic acid metabolism; arachidonic acid is the precursor for pro-inflammatory leukotrienes that threaten helminth survival, and our findings suggest that some modulation of arachidonic acid activity in the STH-infected gut may occur through the increase of arachidonic acid metabolizing bacteria. CONCLUSIONS For the first time, we identify specific members of the gut microbiome that discriminate between moderately/heavily STH-infected and non-infected states across very diverse geographical regions using two different statistical methods. We also identify microbiome-encoded biological functions associated with the STH infections, which are associated potentially with STH survival strategies, and changes in the host environment. These results provide a novel insight of the cross-kingdom interactions in the human gut ecosystem by unlocking the microbiome assemblages at taxonomic, genetic, and functional levels so that advances towards key mechanistic studies can be made.
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Affiliation(s)
- Bruce A. Rosa
- McDonnell Genome Institute, Washington University, St. Louis, MO 63108 USA
| | - Taniawati Supali
- Department of Parasitology, Faculty of Medicine, Universitas Indonesia, Jakarta, Indonesia
| | - Lincoln Gankpala
- Public Health and Medical Research, National Public Health Institute of Liberia, Charlesville, Liberia
| | - Yenny Djuardi
- Department of Parasitology, Faculty of Medicine, Universitas Indonesia, Jakarta, Indonesia
| | - Erliyani Sartono
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - Yanjiao Zhou
- Microbial Genomics, The Jackson Laboratory for Genomic Medicine, Farmington, CT USA
| | - Kerstin Fischer
- Department of Medicine, Washington University School of Medicine, St. Louis, MO USA
| | - John Martin
- McDonnell Genome Institute, Washington University, St. Louis, MO 63108 USA
| | - Rahul Tyagi
- McDonnell Genome Institute, Washington University, St. Louis, MO 63108 USA
| | - Fatorma K. Bolay
- Public Health and Medical Research, National Public Health Institute of Liberia, Charlesville, Liberia
| | - Peter U. Fischer
- Department of Medicine, Washington University School of Medicine, St. Louis, MO USA
| | - Maria Yazdanbakhsh
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - Makedonka Mitreva
- McDonnell Genome Institute, Washington University, St. Louis, MO 63108 USA
- Department of Medicine, Washington University School of Medicine, St. Louis, MO USA
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Prada JM, Touloupou P, Adriko M, Tukahebwa EM, Lamberton PHL, Hollingsworth TD. Understanding the relationship between egg- and antigen-based diagnostics of Schistosoma mansoni infection pre- and post-treatment in Uganda. Parasit Vectors 2018; 11:21. [PMID: 29310695 PMCID: PMC5759883 DOI: 10.1186/s13071-017-2580-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 12/06/2017] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Schistosomiasis is a major socio-economic and public health problem in many sub-Saharan African countries. After large mass drug administration (MDA) campaigns, prevalence of infection rapidly returns to pre-treatment levels. The traditional egg-based diagnostic for schistosome infections, Kato-Katz, is being substituted in many settings by circulating antigen recognition-based diagnostics, usually the point-of-care circulating cathodic antigen test (CCA). The relationship between these diagnostics is poorly understood, particularly after treatment in both drug-efficacy studies and routine monitoring. RESULTS We created a model of schistosome infections to better understand and quantify the relationship between these two egg- and adult worm antigen-based diagnostics. We focused particularly on the interpretation of "trace" results after CCA testing. Our analyses suggest that CCA is generally a better predictor of prevalence, particularly after treatment, and that trace CCA results are typically associated with truly infected individuals. CONCLUSIONS Even though prevalence rises to pre-treatment levels only six months after MDAs, our model suggests that the average intensity of infection is much lower, and is probably in part due to a small burden of surviving juveniles from when the treatment occurred. This work helps to better understand CCA diagnostics and the interpretation of post-treatment prevalence estimations.
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Affiliation(s)
- Joaquín M. Prada
- Department of Mathematics, University of Warwick, Coventry, UK
- School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
| | | | - Moses Adriko
- Vector Control Division, Ministry of Health, Uganda, Kampala, Uganda
| | | | - Poppy H. L. Lamberton
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
- Wellcome Centre for Molecular Parasitology, University of Glasgow, Glasgow, UK
| | - T. Déirdre Hollingsworth
- Department of Mathematics, University of Warwick, Coventry, UK
- Big Data Institute, University of Oxford, Oxford, UK
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Marinho CC, Grobério AC, Silva CTFD, Lima TLFD, Santos RCD, Araújo LGD, Reis VWD, Machado-Coelho GLL. Morbidity of schistosomiasis mansoni in a low endemic setting in Ouro Preto, Minas Gerais, Brazil. Rev Soc Bras Med Trop 2017; 50:805-811. [DOI: 10.1590/0037-8682-0009-2017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 12/14/2017] [Indexed: 11/22/2022] Open
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Sousa SRMD, Carvalho ADQ, Cardoso JFN, Coelho PMZ, Geiger SM, Enk MJ. Schistosomiasis in the Amazon region: is the current diagnostic strategy still appropriate? Rev Soc Bras Med Trop 2017; 50:848-852. [DOI: 10.1590/0037-8682-0097-2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 08/24/2017] [Indexed: 11/21/2022] Open
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Bärenbold O, Raso G, Coulibaly JT, N’Goran EK, Utzinger J, Vounatsou P. Estimating sensitivity of the Kato-Katz technique for the diagnosis of Schistosoma mansoni and hookworm in relation to infection intensity. PLoS Negl Trop Dis 2017; 11:e0005953. [PMID: 28976979 PMCID: PMC5643140 DOI: 10.1371/journal.pntd.0005953] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 10/16/2017] [Accepted: 09/12/2017] [Indexed: 12/29/2022] Open
Abstract
The Kato-Katz technique is the most widely used diagnostic method in epidemiologic surveys and drug efficacy trials pertaining to intestinal schistosomiasis and soil-transmitted helminthiasis. However, the sensitivity of the technique is low, particularly for the detection of light-intensity helminth infections. Examination of multiple stool samples reduces the diagnostic error; yet, most studies rely on a single Kato-Katz thick smear, thus underestimating infection prevalence. We present a model which estimates the sensitivity of the Kato-Katz technique in Schistosoma mansoni and hookworm, as a function of infection intensity for repeated stool sampling and provide estimates of the age-dependent 'true' prevalence. We find that the sensitivity for S. mansoni diagnosis is dominated by missed light infections, which have a low probability to be diagnosed correctly even through repeated sampling. The overall sensitivity strongly depends on the mean infection intensity. In particular at an intensity of 100 eggs per gram of stool (EPG), we estimate a sensitivity of 50% and 80% for one and two samples, respectively. At an infection intensity of 300 EPG, we estimate a sensitivity of 62% for one sample and 90% for two samples. The sensitivity for hookworm diagnosis is dominated by day-to-day variation with typical values for one, two, three, and four samples equal to 50%, 75%, 85%, and 95%, respectively, while it is only weakly dependent on the mean infection intensity in the population. We recommend taking at least two samples and estimate the 'true' prevalence of S. mansoni considering the dependence of the sensitivity on the mean infection intensity and the 'true' hookworm prevalence by taking into account the sensitivity given in the current study.
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Affiliation(s)
- Oliver Bärenbold
- Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- Faculty of Science, University of Basel, Basel, Switzerland
| | - Giovanna Raso
- Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- Faculty of Science, University of Basel, Basel, Switzerland
| | - Jean T. Coulibaly
- Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- Faculty of Science, University of Basel, Basel, Switzerland
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
| | - Eliézer K. N’Goran
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
| | - Jürg Utzinger
- Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- Faculty of Science, University of Basel, Basel, Switzerland
| | - Penelope Vounatsou
- Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- Faculty of Science, University of Basel, Basel, Switzerland
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31
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Ferreira FT, Fidelis TA, Pereira TA, Otoni A, Queiroz LC, Amâncio FF, Antunes CM, Lambertucci JR. Sensitivity and specificity of the circulating cathodic antigen rapid urine test in the diagnosis of Schistosomiasis mansoni infection and evaluation of morbidity in a low- endemic area in Brazil. Rev Soc Bras Med Trop 2017; 50:358-364. [PMID: 28700054 DOI: 10.1590/0037-8682-0423-2016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 05/16/2017] [Indexed: 12/28/2022] Open
Abstract
INTRODUCTION: The Kato-Katz technique is the standard diagnostic test for Schistosoma mansoni infection in rural areas. However, the utility of this method is severely limited by the day-to-day variability in host egg excretion in the stool. In high-transmission areas, the point-of-care circulating cathodic antigen (POC-CCA) urine assay has proven to be a reliable test. However, investigations of the reliability of the POC-CCA assay in low-transmission regions are under way. This study aimed to evaluate the sensitivity and specificity of the POC-CCA assay and the morbidity of schistosomiasis in a low-endemic area in Brazil. METHODS: Pains City is a low-transmission zone for schistosomiasis. A total of 300 subjects aged 7-76 years were randomly selected for the POC-CCA cassette test. For S. mansoni diagnosis, three stool samples on six slides were compared with one urine sample for each subject. The sensitivity and specificity in the absence of a gold standard were calculated using latent class analysis. Clinical examinations and abdominal ultrasounds were performed in 181 volunteers to evaluate morbidity associated with schistosomiasis. RESULTS: The sensitivity and specificity of the Kato-Katz technique were 25.6% and 94.6%, respectively. By contrast, the sensitivity and specificity of the POC-CCA assay were 68.1% and 72.8%, respectively. Hepatosplenic schistosomiasis was diagnosed in two patients (1.1%). CONCLUSIONS: Overall, the POC-CCA urine assay proved to be a useful test for diagnosing S. mansoni in a low-endemic area in Brazil. Severe clinical forms of schistosomiasis can be present even in such low-endemic areas.
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Affiliation(s)
- Fernanda Teixeira Ferreira
- Serviço de Doenças Infecciosas e Parasitárias, Departamento de Clínica Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Thiago André Fidelis
- Serviço de Doenças Infecciosas e Parasitárias, Departamento de Clínica Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Thiago Almeida Pereira
- Serviço de Doenças Infecciosas e Parasitárias, Departamento de Clínica Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil.,Immunopathogenesis section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Alba Otoni
- Serviço de Doenças Infecciosas e Parasitárias, Departamento de Clínica Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil.,Núcleo de Pesquisas em Epidemiologia e Saúde Coletiva, Universidade Federal de São João del-Rei , Divinópolis, MG, Brasil
| | - Leonardo Campos Queiroz
- Serviço de Doenças Infecciosas e Parasitárias, Departamento de Clínica Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Frederico Figueiredo Amâncio
- Serviço de Doenças Infecciosas e Parasitárias, Departamento de Clínica Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Carlos Maurício Antunes
- Instituto de Ensino e Pesquisa, Santa Casa de Misericórdia de Belo Horizonte, Belo Horizonte, MG, Brasil
| | - José Roberto Lambertucci
- Serviço de Doenças Infecciosas e Parasitárias, Departamento de Clínica Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
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32
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Easton AV, Oliveira RG, Walker M, O'Connell EM, Njenga SM, Mwandawiro CS, Webster JP, Nutman TB, Anderson RM. Sources of variability in the measurement of Ascaris lumbricoides infection intensity by Kato-Katz and qPCR. Parasit Vectors 2017; 10:256. [PMID: 28545561 PMCID: PMC5445470 DOI: 10.1186/s13071-017-2164-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 05/01/2017] [Indexed: 12/20/2022] Open
Abstract
Background Understanding and quantifying the sources and implications of error in the measurement of helminth egg intensity using Kato-Katz (KK) and the newly emerging “gold standard” quantitative polymerase chain reaction (qPCR) technique is necessary for the appropriate design of epidemiological studies, including impact assessments for deworming programs. Methods Repeated measurements of Ascaris lumbricoides infection intensity were made from samples collected in western Kenya using the qPCR and KK techniques. These data were combined with data on post-treatment worm expulsions. Random effects regression models were used to quantify the variability associated with different technical and biological factors for qPCR and KK diagnosis. The relative precision of these methods was compared, as was the precision of multiple qPCR replicates. Results For both KK and qPCR, intensity measurements were largely determined by the identity of the stool donor. Stool donor explained 92.4% of variability in qPCR measurements and 54.5% of observed measurement variance for KK. An additional 39.1% of variance in KK measurements was attributable to having expelled adult A. lumbricoides worms following anthelmintic treatment. For qPCR, the remaining 7.6% of variability was explained by the efficiency of the DNA extraction (2.4%), plate-to-plate variability (0.2%) and other residual factors (5%). Differences in replicate measurements by qPCR were comparatively small. In addition to KK variability based on stool donor infection levels, the slide reader was highly statistically significant, although it only explained 1.4% of the total variation. In a comparison of qPCR and KK variance to mean ratios under ideal conditions, the coefficient of variation was on average 3.6 times larger for KK highlighting increased precision of qPCR. Conclusions Person-to-person differences explain the majority of variability in egg intensity measurements by qPCR and KK, with very little additional variability explained by the technical factors associated with the practical implementation of these techniques. qPCR provides approximately 3.6 times more precision in estimating A. lumbricoides egg intensity than KK, and could potentially be made more cost-effective by testing each sample only once without diminishing the power of a study to assess population-level intensity and prevalence. Electronic supplementary material The online version of this article (doi:10.1186/s13071-017-2164-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alice V Easton
- Helminth Immunology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, 20814, USA. .,Department of Infectious Disease Epidemiology and London Centre for Neglected Tropical Disease Research (LCNTDR), Faculty of Medicine, Imperial College London St Mary's Campus, London, W2 1PG, UK.
| | - Rita G Oliveira
- Department of Infectious Disease Epidemiology and London Centre for Neglected Tropical Disease Research (LCNTDR), Faculty of Medicine, Imperial College London St Mary's Campus, London, W2 1PG, UK
| | - Martin Walker
- Department of Infectious Disease Epidemiology and London Centre for Neglected Tropical Disease Research (LCNTDR), Faculty of Medicine, Imperial College London St Mary's Campus, London, W2 1PG, UK.,Department of Pathobiology and Population Science and London Centre for Neglected Tropical Disease Research (LCNTDR), The Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire, AL97TA, UK
| | - Elise M O'Connell
- Helminth Immunology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, 20814, USA
| | - Sammy M Njenga
- The Eastern and Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute, Nairobi, Kenya
| | - Charles S Mwandawiro
- The Eastern and Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute, Nairobi, Kenya
| | - Joanne P Webster
- Department of Infectious Disease Epidemiology and London Centre for Neglected Tropical Disease Research (LCNTDR), Faculty of Medicine, Imperial College London St Mary's Campus, London, W2 1PG, UK.,Department of Pathobiology and Population Science and London Centre for Neglected Tropical Disease Research (LCNTDR), The Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire, AL97TA, UK
| | - Thomas B Nutman
- Helminth Immunology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, 20814, USA
| | - Roy M Anderson
- Department of Infectious Disease Epidemiology and London Centre for Neglected Tropical Disease Research (LCNTDR), Faculty of Medicine, Imperial College London St Mary's Campus, London, W2 1PG, UK
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33
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Chernet A, Kling K, Sydow V, Kuenzli E, Hatz C, Utzinger J, van Lieshout L, Marti H, Nickel B, Labhardt ND, Neumayr A. Accuracy of Diagnostic Tests for Schistosoma mansoni Infection in Asymptomatic Eritrean Refugees: Serology and Point-of-Care Circulating Cathodic Antigen Against Stool Microscopy. Clin Infect Dis 2017; 65:568-574. [DOI: 10.1093/cid/cix366] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 04/17/2017] [Indexed: 12/23/2022] Open
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Colley DG, Andros TS, Campbell CH. Schistosomiasis is more prevalent than previously thought: what does it mean for public health goals, policies, strategies, guidelines and intervention programs? Infect Dis Poverty 2017; 6:63. [PMID: 28327187 PMCID: PMC5361841 DOI: 10.1186/s40249-017-0275-5] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 03/06/2017] [Indexed: 01/08/2023] Open
Abstract
Mapping and diagnosis of infections by the three major schistosome species (Schistosoma haematobium, S. mansoni and S. japonicum) has been done with assays that are known to be specific but increasingly insensitive as prevalence declines or in areas with already low prevalence of infection. This becomes a true challenge to achieving the goal of elimination of schistosomiasis because the multiplicative portion of the life-cycle of schistosomes, in the snail vector, favors continued transmission as long as even a few people maintain low numbers of worms that pass eggs in their excreta. New mapping tools based on detection of worm antigens (circulating cathodic antigen – CCA; circulating anodic antigen – CAA) in urine of those infected are highly sensitive and the CAA assay is reported to be highly specific. Using these tools in areas of low prevalence of all three of these species of schistosomes has demonstrated that more people harbor adult worms than are regularly excreting eggs at a level detectable by the usual stool assay (Kato-Katz) or by urine filtration. In very low prevalence areas this is sometimes 6- to10-fold more. Faced with what appears to be a sizable population of “egg-negative/worm-positive schistosomiasis” especially in areas of very low prevalence, national NTD programs are confounded about what guidelines and strategies they should enact if they are to proceed toward a goal of elimination. There is a critical need for continued evaluation of the assays involved and to understand the contribution of this “egg-negative/worm-positive schistosomiasis” condition to both individual morbidity and community transmission. There is also a critical need for new guidelines based on the use of these more sensitive assays for those national NTD programs that wish to move forward to strategies designed for elimination.
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Affiliation(s)
- Daniel G Colley
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, 500 DW Brooks Drive, Room 330B Coverdell Center, Athens, Georgia, 30602, USA. .,Department of Microbiology, University of Georgia, Athens, Georgia, 30602, USA.
| | - Tamara S Andros
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, 500 DW Brooks Drive, Room 330B Coverdell Center, Athens, Georgia, 30602, USA
| | - Carl H Campbell
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, 500 DW Brooks Drive, Room 330B Coverdell Center, Athens, Georgia, 30602, USA
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35
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Haggag AA, Rabiee A, Abd Elaziz KM, Gabrielli AF, Abdel Hay R, Ramzy RM. Mapping of Schistosoma mansoni in the Nile Delta, Egypt: Assessment of the prevalence by the circulating cathodic antigen urine assay. Acta Trop 2017; 167:9-17. [PMID: 27965144 DOI: 10.1016/j.actatropica.2016.11.038] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Revised: 11/18/2016] [Accepted: 11/27/2016] [Indexed: 11/24/2022]
Abstract
In line with WHO recommendations on elimination of schistosomiasis, accurate identification of all areas of residual transmission is a key step to design and implement measures aimed at interrupting transmission in low-endemic settings. To this purpose, we assessed the prevalence of active S. mansoni infection in five pilot governorates in the Nile Delta of Egypt by examining schoolchildren (6-15 years) using the Urine-Circulating Cathodic Antigen (Urine-CCA) cassette test; we also carried out the standard Kato-Katz (KK) thick smear, the monitoring and evaluation tool employed by Egypt's national schistosomiasis control programme. Prevalence rates determined by the Urine-CCA test for all governorates were higher than those determined by KK (p<0.01). Of 35 districts surveyed in the five governorates, S. mansoni infection was detected in 19 districts (54.3%) using KK, and in 31 districts (88.6%) by Urine-CCA (χ2=9.94; P=0.0016). S. mansoni infections were detected by Urine-CCA, but not by KK in 12 districts (34.3%), and infection was not detected by either of the two diagnostic methods in four districts in Qalyubia governorate. Males and higher age-groups have significantly higher Urine-CCA prevalence rates. Based on the findings of the current S. mansoni mapping exercise, authorities of the Ministry of Health and Population (MoHP) adopted a new elimination strategy by readjusting thresholds for mass treatment with praziquantel and targeting all transmission areas. MoHP is now planning to remap in all other endemic governorates using Urine-CCA with the aim of identifying all areas of transmission where the elimination strategy should be applied.
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The impact of prenatal exposure to parasitic infections and to anthelminthic treatment on antibody responses to routine immunisations given in infancy: Secondary analysis of a randomised controlled trial. PLoS Negl Trop Dis 2017; 11:e0005213. [PMID: 28178298 PMCID: PMC5298230 DOI: 10.1371/journal.pntd.0005213] [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] [Received: 08/15/2016] [Accepted: 11/28/2016] [Indexed: 11/25/2022] Open
Abstract
Background Chronic parasitic infections are associated with active immunomodulation which may include by-stander effects on unrelated antigens. It has been suggested that pre-natal exposure to parasitic infections in the mother impacts immunological development in the fetus and hence the offspring’s response to vaccines, and that control of parasitic infection among pregnant women will therefore be beneficial. Methodology/Principal findings We used new data from the Entebbe Mother and Baby Study, a trial of anthelminthic treatment during pregnancy conducted in Uganda, to further investigate this hypothesis. 2705 mothers were investigated for parasitic infections and then randomised to albendazole (400mg) versus placebo and praziquantel (40mg/kg) during pregnancy in a factorial design. All mothers received sulfadoxine/pyrimethamine for presumptive treatment of malaria. Offspring received Expanded Programme on Immunisation vaccines at birth, six, 10 and 14 weeks. New data on antibody levels to diphtheria toxin, three pertussis antigens, Haemophilus influenzae type B (HiB) and Hepatitis B, measured at one year (April 2004 –May 2007) from 1379 infants were analysed for this report. Additional observational analyses relating maternal infections to infant vaccine responses were also conducted. Helminth infections were highly prevalent amongst mothers (hookworm 43.1%, Mansonella 20.9%, Schistosoma mansoni 17.3%, Strongyloides 11.7%, Trichuris 8.1%) and 9.4% had malaria at enrolment. In the trial analysis we found no overall effect of either anthelminthic intervention on the measured infant vaccine responses. In observational analyses, no species was associated with suppressed responses. Strongyloidiasis was associated with enhanced responses to pertussis toxin, HiB and Hep B vaccine antigens. Conclusions/Significance Our results do not support the hypothesis that routine anthelminthic treatment during pregnancy has a benefit for the infant’s vaccine response, or that maternal helminth infection has a net suppressive effect on the offspring’s response to vaccines. Trial Registration ISRCTN.com ISRCTN32849447 Parasitic infections, such as worms and malaria, have potent effects on the human immune system. These effects include modification of immune responses in the fetus and infant if a mother has a parasitic infection during pregnancy. These immunological changes can influence the way a child responds to the same infection when exposed in later life. It has been suggested that the immunological changes might also influence how the child responds to the vaccines given in infancy, and that treating mothers for parasitic infections when they are pregnant might be helpful. In this study we compared responses to vaccines between infants of mothers who had, or had not, been treated for worms while they were pregnant. We found no overall differences. We also compared vaccine responses between groups of mothers with and without parasitic infections. We found no evidence that the parasitic infections were associated with reduced responses in the children. This means that, although treating worms during pregnancy may have some benefits, improvements in the children’s responses to vaccines are not likely to be among them.
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Webb EL, Nampijja M, Kaweesa J, Kizindo R, Namutebi M, Nakazibwe E, Oduru G, Kabubi P, Kabagenyi J, Nkurunungi G, Kizito D, Muhangi L, Akello M, Verweij JJ, Nerima B, Tukahebwa E, Elliott AM, Sanya R, Mirembe B, Okello J, Levin J, Zziwa C, Tumusiime J, Sewankambo M, Nsubuga D, Cose S, Wammes L, Niwagaba E, Kabami G, Abayo E, Muwonge F, Abiriga D, Nannozi V, Kaweesa J. Helminths are positively associated with atopy and wheeze in Ugandan fishing communities: results from a cross-sectional survey. Allergy 2016; 71:1156-69. [PMID: 26918891 PMCID: PMC4949563 DOI: 10.1111/all.12867] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/18/2016] [Indexed: 01/15/2023]
Abstract
Background Parasitic helminths are potent immunomodulators and chronic infections may protect against allergy‐related disease and atopy. We conducted a cross‐sectional survey to test the hypothesis that in heavily helminth‐exposed fishing villages on Lake Victoria, Uganda, helminth infections would be inversely associated with allergy‐related conditions. Methods A household survey was conducted as baseline to an anthelminthic intervention trial. Outcomes were reported wheeze in last year, atopy assessed both by skin prick test (SPT) and by the measurement of allergen‐specific IgE to dust mites and cockroach in plasma. Helminth infections were ascertained by stool, urine and haemoparasitology. Associations were examined using multivariable regression. Results Two thousand three hundred and sixteen individuals were surveyed. Prevalence of reported wheeze was 2% in under‐fives and 5% in participants ≥5 years; 19% had a positive SPT; median Dermatophagoides‐specific IgE and cockroach‐specific IgE were 1440 and 220 ng/ml, respectively. S. mansoni, N. americanus, S. stercoralis, T. trichiura, M. perstans and A. lumbricoides prevalence was estimated as 51%, 22%, 12%, 10%, 2% and 1%, respectively. S. mansoni was positively associated with Dermatophagoides‐specific IgE [adjusted geometric mean ratio (aGMR) (95% confidence interval) 1.64 (1.23, 2.18)]; T. trichiura with SPT [adjusted odds ratio (aOR) 2.08 (1.38, 3.15)]; M. perstans with cockroach‐specific IgE [aGMR 2.37 (1.39, 4.06)], A. lumbricoides with wheeze in participants ≥5 years [aOR 6.36 (1.10, 36.63)] and with Dermatophagoides‐specific IgE [aGMR 2.34 (1.11, 4.95)]. No inverse associations were observed. Conclusions Contrary to our hypothesis, we found little evidence of an inverse relationship between helminths and allergy‐related outcomes, but strong evidence that individuals with certain helminths were more prone to atopy in this setting.
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Affiliation(s)
- E. L. Webb
- London School of Hygiene and Tropical Medicine London UK
| | - M. Nampijja
- MRC/UVRI Uganda Research Unit on AIDS Entebbe Uganda
| | - J. Kaweesa
- Vector Control Division Ministry of Health Kampala Uganda
| | - R. Kizindo
- MRC/UVRI Uganda Research Unit on AIDS Entebbe Uganda
| | - M. Namutebi
- MRC/UVRI Uganda Research Unit on AIDS Entebbe Uganda
| | | | | | - P. Kabubi
- MRC/UVRI Uganda Research Unit on AIDS Entebbe Uganda
| | - J. Kabagenyi
- MRC/UVRI Uganda Research Unit on AIDS Entebbe Uganda
| | - G. Nkurunungi
- MRC/UVRI Uganda Research Unit on AIDS Entebbe Uganda
| | - D. Kizito
- MRC/UVRI Uganda Research Unit on AIDS Entebbe Uganda
| | - L. Muhangi
- MRC/UVRI Uganda Research Unit on AIDS Entebbe Uganda
| | - M. Akello
- MRC/UVRI Uganda Research Unit on AIDS Entebbe Uganda
| | - J. J. Verweij
- Laboratory for Medical Microbiology and Immunology St Elisabeth Hospital LC Tilburg the Netherlands
| | - B. Nerima
- MRC/UVRI Uganda Research Unit on AIDS Entebbe Uganda
| | - E. Tukahebwa
- Vector Control Division Ministry of Health Kampala Uganda
| | - A. M. Elliott
- London School of Hygiene and Tropical Medicine London UK
- MRC/UVRI Uganda Research Unit on AIDS Entebbe Uganda
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Assessing stool quantities generated by three specific Kato-Katz thick smear templates employed in different settings. Infect Dis Poverty 2016; 5:58. [PMID: 27364623 PMCID: PMC4929780 DOI: 10.1186/s40249-016-0150-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 05/19/2016] [Indexed: 02/07/2023] Open
Abstract
Background The Kato-Katz technique is recommended for the diagnosis of helminth infections in epidemiological surveys, drug efficacy studies and monitoring of control interventions. We assessed the comparability of the average amount of faeces generated by three Kato-Katz templates included in test kits from two different providers. Methods Nine hundred Kato-Katz thick smear preparations were done; 300 per kit. Empty slides, slides plus Kato-Katz template filled with stool and slides plus stool after careful removal of the template were weighed to the nearest 0.1 mg. The average amount of stool that was generated on the slide was calculated for each template, stratified by standard categories of stool consistency (i.e. mushy, soft, sausage-shaped, hard and clumpy). Results The average amount of stool generated on slides was 40.7 mg (95 % confidence interval (CI): 40.0–41.4 mg), 40.3 mg (95 % CI: 39.7–40.9 mg) and 42.8 mg (95 % CI: 42.2–43.3 mg) for the standard Vestergaard Frandsen template, and two different templates from the Chinese Center for Disease Control and Prevention (China CDC), respectively. Mushy stool resulted in considerably lower average weights when the Vestergaard Frandsen (37.0 mg; 95 % CI: 34.9–39.0 mg) or new China CDC templates (37.4 mg; 95 % CI: 35.9–38.9 mg) were used, compared to the old China CDC template (42.2 mg; 95 % CI: 40.7–43.7 mg) and compared to other stool consistency categories. Conclusion The average amount of stool generated by three specific Kato-Katz templates was similar (40.3–42.8 mg). Since the multiplication factor is somewhat arbitrary and small changes only have little effect on infection intensity categories, it is suggested that the standard multiplication factor of 24 should be kept for the calculation of eggs per gram of faeces for all investigated templates. Electronic supplementary material The online version of this article (doi:10.1186/s40249-016-0150-9) contains supplementary material, which is available to authorized users.
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Schistosoma mekongi cathepsin B and its use in the development of an immunodiagnosis. Acta Trop 2016; 155:11-9. [PMID: 26655041 DOI: 10.1016/j.actatropica.2015.11.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 11/17/2015] [Accepted: 11/27/2015] [Indexed: 11/24/2022]
Abstract
Schistosomiasis mekongi is one of the most important human parasitic diseases caused by Schistosoma mekongi in South-east Asia. The endemic area is the Mekong River sub-region from Laos to Cambodia. This parasite also infects dogs and pigs which are its alternative host species. Currently, the lack of reliable rapid diagnosis makes it difficult to monitor the infection and spreading of the disease. In this study, we screened the antigens of the parasite with sera of infected mice using Western blotting and identified proteins of interest with LC-MS/MS to obtain potential candidate proteins for diagnostic development. This assay yielded 2 immunoreactive bands at molecular masses of 31 and 22kDa. The 31kDa protein was the major band identified as cathepsin B, and its gene was cloned to obtain a full cDNA sequence (SmekCatB). The cDNA consisted of 1123bp and its longest reading frame encoded for 342 amino acids with some putative post translation modifications. The recombinant SmekCatB (rSmekCatB) with hexahistidine tag at the C-terminus was expressed in Escherichia coli and purified by Ni-NTA resin under denaturing conditions. The rSmekCatB reacted with sera of S. mekongi-infected mice. Indirect ELISA using rSmekCatB as the antigen to detect mouse antibodies, revealed a sensitivity of 91.67% for schistosomiasis mekongi and the specificity of 100%. Our data suggested that SmekCatB is one of the most promising parasitic antigens that could be used for the diagnosis of S. mekongi infection.
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Walker M, Mabud TS, Olliaro PL, Coulibaly JT, King CH, Raso G, Scherrer AU, Stothard JR, Sousa-Figueiredo JC, Stete K, Utzinger J, Basáñez MG. New approaches to measuring anthelminthic drug efficacy: parasitological responses of childhood schistosome infections to treatment with praziquantel. Parasit Vectors 2016; 9:41. [PMID: 26813154 PMCID: PMC4728951 DOI: 10.1186/s13071-016-1312-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 11/20/2015] [Indexed: 11/30/2022] Open
Abstract
Background By 2020, the global health community aims to control and eliminate human helminthiases, including schistosomiasis in selected African countries, principally by preventive chemotherapy (PCT) through mass drug administration (MDA) of anthelminthics. Quantitative monitoring of anthelminthic responses is crucial for promptly detecting changes in efficacy, potentially indicative of emerging drug resistance. Statistical models offer a powerful means to delineate and compare efficacy among individuals, among groups of individuals and among populations. Methods We illustrate a variety of statistical frameworks that offer different levels of inference by analysing data from nine previous studies on egg counts collected from African children before and after administration of praziquantel. Results We quantify responses to praziquantel as egg reduction rates (ERRs), using different frameworks to estimate ERRs among population strata, as average responses, and within strata, as individual responses. We compare our model-based average ERRs to corresponding model-free estimates, using as reference the World Health Organization (WHO) 90 % threshold of optimal efficacy. We estimate distributions of individual responses and summarize the variation among these responses as the fraction of ERRs falling below the WHO threshold. Conclusions Generic models for evaluating responses to anthelminthics deepen our understanding of variation among populations, sub-populations and individuals. We discuss the future application of statistical modelling approaches for monitoring and evaluation of PCT programmes targeting human helminthiases in the context of the WHO 2020 control and elimination goals. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1312-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Martin Walker
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, London, W2 1PG, UK. .,London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, Imperial College London, London, W2 1PG, UK.
| | - Tarub S Mabud
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, London, W2 1PG, UK. .,Present address: Stanford School of Medicine, 291 Campus Drive, Stanford, CA, 94305, USA.
| | - Piero L Olliaro
- UNICEF/UNDP/World Bank/WHO Special Programme on Research and Training in Tropical Diseases (TDR), World Health Organization, Av. Appia 20, CH-1211, Geneva 27, Switzerland. .,Centre for Tropical Medicine and Global Health Nuffield Department of Medicine Research Building, University of Oxford Old Road Campus, Roosevelt Drive, Oxford, OX3 7FZ, UK.
| | - Jean T Coulibaly
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland. .,University of Basel, P.O. Box, CH-4003, Basel, Switzerland. .,Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 22 BP 770, Abidjan 22, Côte d'Ivoire. .,Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01 BP 1303, Abidjan 01, Côte d'Ivoire.
| | - Charles H King
- Center for Global Health and Diseases, Case Western Reserve University, 2109 Adelbert Road, Cleveland, OH, 44106, USA. .,Schistosomiasis Consortium for Operational Research and Evaluation, University of Georgia, 500 D W Brooks Drive, Athens, GA, 30602, USA.
| | - Giovanna Raso
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland. .,University of Basel, P.O. Box, CH-4003, Basel, Switzerland.
| | - Alexandra U Scherrer
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Rämistrasse 100, CH-8091, Zurich, Switzerland.
| | - J Russell Stothard
- Department of Parasitology, London School of Tropical Medicine, Liverpool, L3 5QA, UK.
| | - José Carlos Sousa-Figueiredo
- Centro de Investigação em Saúde de Angola (Health Research Center in Angola), Rua direita do Caxito, Hospital Provincial, Bengo, Angola. .,Department of Life Sciences, Natural History Museum, Wolfson Wellcome Biomedical Laboratories, Cromwell Road, London, SW7 5BD, UK.
| | - Katarina Stete
- Center for Infectious Diseases and Travel Medicine, Department of Medicine, University Hospital Freiburg, Hugstetter Strasse 55, D-79106, Freiburg, Germany.
| | - Jürg Utzinger
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland. .,University of Basel, P.O. Box, CH-4003, Basel, Switzerland.
| | - Maria-Gloria Basáñez
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, London, W2 1PG, UK. .,London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, Imperial College London, London, W2 1PG, UK.
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Abstract
Schistosomiasis is a major neglected tropical disease that afflicts more than 240 million people, including many children and young adults, in the tropics and subtropics. The disease is characterized by chronic infections with significant residual morbidity and is of considerable public health importance, with substantial socioeconomic impacts on impoverished communities. Morbidity reduction and eventual elimination through integrated intervention measures are the focuses of current schistosomiasis control programs. Precise diagnosis of schistosome infections, in both mammalian and snail intermediate hosts, will play a pivotal role in achieving these goals. Nevertheless, despite extensive efforts over several decades, the search for sensitive and specific diagnostics for schistosomiasis is ongoing. Here we review the area, paying attention to earlier approaches but emphasizing recent developments in the search for new diagnostics for schistosomiasis with practical applications in the research laboratory, the clinic, and the field. Careful and rigorous validation of these assays and their cost-effectiveness will be needed, however, prior to their adoption in support of policy decisions for national public health programs aimed at the control and elimination of schistosomiasis.
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Assaré RK, Hürlimann E, Ouattara M, N'Guessan NA, Tian-Bi YNT, Yapi A, Yao PK, Coulibaly JT, Knopp S, N'Goran EK, Utzinger J. Sustaining the Control of Schistosoma mansoni in Western Côte d'Ivoire: Baseline Findings Before the Implementation of a Randomized Trial. Am J Trop Med Hyg 2015; 94:352-60. [PMID: 26598571 DOI: 10.4269/ajtmh.15-0530] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Accepted: 10/19/2015] [Indexed: 12/22/2022] Open
Abstract
We report baseline findings before the implementation of a 4-year intervention trial designed to assess the impact of three different school-based treatment schedules with praziquantel to sustain the control of intestinal schistosomiasis. The baseline survey was conducted in 75 schools of western Côte d'Ivoire previously identified with moderate Schistosoma mansoni endemicity (prevalence: 10-24% in children aged 13-14 years). Three stool samples collected over consecutive days were subjected to duplicate Kato-Katz thick smears each. A questionnaire was administered to collect village-specific information that is relevant for schistosomiasis transmission. Overall, 4,953 first graders (aged 5-8 years) and 7,011 school children (aged 9-12 years) had complete parasitologic data. The overall prevalence of S. mansoni was 5.4% among first graders and 22.1% in 9- to 12-year-old children. Open defecation was practiced in all villages. The current baseline findings will be important to better understand the dynamics of S. mansoni prevalence and intensity over the course of this trial that might be governed by village characteristics and specific treatment interventions.
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Affiliation(s)
- Rufin K Assaré
- 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; Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Eveline Hürlimann
- 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; Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Mamadou Ouattara
- 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; Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Nicaise A N'Guessan
- 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; Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Yves-Nathan T Tian-Bi
- 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; Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Ahoua Yapi
- 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; Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Patrick K Yao
- 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; Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London, 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; Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Stefanie Knopp
- 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; Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Eliézer K N'Goran
- 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; Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Jürg Utzinger
- 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; Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London, United Kingdom
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Siqueira LMV, Gomes LI, Oliveira E, Oliveira ERD, Oliveira ÁAD, Enk MJ, Carneiro NF, Rabello A, Coelho PMZ. Evaluation of parasitological and molecular techniques for the diagnosis and assessment of cure of schistosomiasis mansoni in a low transmission area. Mem Inst Oswaldo Cruz 2015; 110:209-14. [PMID: 25946244 PMCID: PMC4489451 DOI: 10.1590/0074-02760140375] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 01/26/2015] [Indexed: 11/22/2022] Open
Abstract
This study evaluated parasitological and molecular techniques for the diagnosis and
assessment of cure of schistosomiasis mansoni. A population-based study was performed
in 201 inhabitants from a low transmission locality named Pedra Preta, municipality
of Montes Claros, state of Minas Gerais, Brazil. Four stool samples were analysed
using two techniques, the Kato-Katz® (KK) technique (18 slides) and the
TF-Test®, to establish the infection rate. The positivity rate of 18 KK
slides of four stool samples was 28.9% (58/201) and the combined parasitological
techniques (KK+TF-Test®) produced a 35.8% positivity rate (72/201).
Furthermore, a polymerase chain reaction (PCR)-ELISA assay produced a positivity rate
of 23.4% (47/201) using the first sample. All 72 patients with positive
parasitological exams were treated with a single dose of Praziquantel® and
these patients were followed-up 30, 90 and 180 days after treatment to establish the
cure rate. Cure rates obtained by the analysis of 12 KK slides were 100%, 100% and
98.4% at 30, 90 and 180 days after treatment, respectively. PCR-ELISA revealed cure
rates of 98.5%, 95.5% and 96.5%, respectively. The diagnostic and assessment of cure
for schistosomiasis may require an increased number of KK slides or a test with
higher sensitivity, such as PCR-ELISA, in situations of very low parasite load, such
as after therapeutic interventions.
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Affiliation(s)
| | - Luciana Inácia Gomes
- Laboratório de Pesquisas Clínicas, Centro de Pesquisas René Rachou, Fiocruz, Belo Horizonte, MG, Brasil
| | - Edward Oliveira
- Laboratório de Pesquisas Clínicas, Centro de Pesquisas René Rachou, Fiocruz, Belo Horizonte, MG, Brasil
| | | | | | | | | | - Ana Rabello
- Laboratório de Pesquisas Clínicas, Centro de Pesquisas René Rachou, Fiocruz, Belo Horizonte, MG, Brasil
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Greter H, Krauth SJ, Ngandolo BNR, Alfaroukh IO, Zinsstag J, Utzinger J. Validation of a Point-of-Care Circulating Cathodic Antigen Urine Cassette Test for Schistosoma mansoni Diagnosis in the Sahel, and Potential Cross-Reaction in Pregnancy. Am J Trop Med Hyg 2015; 94:361-4. [PMID: 26556831 DOI: 10.4269/ajtmh.15-0577] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Accepted: 09/25/2015] [Indexed: 01/10/2023] Open
Abstract
On the shores of Lake Chad, schistosomiasis among mobile pastoralists was investigated in a field laboratory. Point-of-care circulating cathodic antigen (POC-CCA) cassette test, reagent strip, and filtration were conducted on urine samples. Fresh stool samples were subjected to the Kato-Katz technique, and fixed samples were examined with an ether-concentration method at a reference laboratory. POC-CCA urine cassette tests revealed a Schistosoma mansoni prevalence of 6.9%, compared with only 0.5% by stool microscopy. Three pregnant women with otherwise negative urine and stool testing had positive POC-CCA. This observation raises concern of cross-reactivity in pregnancy. Hence, two pregnant women in Switzerland with no history of schistosomiasis were subjected to POC-CCA and one tested positive. Our data suggest that POC-CCA can be performed under extreme Sahelian conditions (e.g., temperatures > 40°C), and it is more sensitive than stool microscopy for S. mansoni diagnosis. However, potential cross-reactivity in pregnancy needs further investigation.
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Affiliation(s)
- Helena Greter
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire; Institut de Recherche en Elevage pour le Développement, N'Djamena, Chad
| | - Stefanie J Krauth
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire; Institut de Recherche en Elevage pour le Développement, N'Djamena, Chad
| | - Bongo N R Ngandolo
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire; Institut de Recherche en Elevage pour le Développement, N'Djamena, Chad
| | - Idriss O Alfaroukh
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire; Institut de Recherche en Elevage pour le Développement, N'Djamena, Chad
| | - Jakob Zinsstag
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire; Institut de Recherche en Elevage pour le Développement, N'Djamena, Chad
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire; Institut de Recherche en Elevage pour le Développement, N'Djamena, Chad
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French MD, Churcher TS, Webster JP, Fleming FM, Fenwick A, Kabatereine NB, Sacko M, Garba A, Toure S, Nyandindi U, Mwansa J, Blair L, Bosqué-Oliva E, Basáñez MG. Estimation of changes in the force of infection for intestinal and urogenital schistosomiasis in countries with schistosomiasis control initiative-assisted programmes. Parasit Vectors 2015; 8:558. [PMID: 26499981 PMCID: PMC4619997 DOI: 10.1186/s13071-015-1138-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 10/03/2015] [Indexed: 11/07/2022] Open
Abstract
Background The last decade has seen an expansion of national schistosomiasis control programmes in Africa based on large-scale preventative chemotherapy. In many areas this has resulted in considerable reductions in infection and morbidity levels in treated individuals. In this paper, we quantify changes in the force of infection (FOI), defined here as the per (human) host parasite establishment rate, to ascertain the impact on transmission of some of these programmes under the umbrella of the Schistosomiasis Control Initiative (SCI). Methods A previous model for the transmission dynamics of Schistosoma mansoni was adapted here to S. haematobium. These models were fitted to longitudinal cohort (infection intensity) monitoring and evaluation data. Changes in the FOI following up to three annual rounds of praziquantel were estimated for Burkina Faso, Mali, Niger, Tanzania, Uganda, and Zambia in sub-Saharan Africa (SSA) according to country, baseline endemicity and schistosome species. Since schistosomiasis transmission is known to be highly focal, changes in the FOI at a finer geographical scale (that of sentinel site) were also estimated for S. mansoni in Uganda. Results Substantial and statistically significant reductions in the FOI relative to baseline were recorded in the majority of, but not all, combinations of country, parasite species, and endemicity areas. At the finer geographical scale assessed within Uganda, marked heterogeneity in the magnitude and direction of the relative changes in FOI was observed that would not have been appreciated by a coarser-scale analysis. Conclusions Reductions in the rate at which humans acquire schistosomes have been achieved in many areas of SSA countries assisted by the SCI, while challenges in effectively reducing transmission persist in others. Understanding the underlying heterogeneity in the impact and performance of the control intervention at the level of the transmission site will become increasingly important for programmes transitioning from morbidity reduction to elimination of infection. Such analyses will require a fine-scale approach. The lack of association found between programmatic variables, such as therapeutic treatment coverage (recorded at district level) and changes in FOI (at sentinel site level) is discussed and recommendations are made.
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Affiliation(s)
- Michael D French
- Schistosomiasis Control Initiative, Faculty of Medicine, Imperial College London, St. Mary's Hospital, Norfolk Place, London, W2 1PG, UK.
| | - Thomas S Churcher
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, Norfolk Place, London, W2 1PG, UK.
| | - Joanne P Webster
- Schistosomiasis Control Initiative, Faculty of Medicine, Imperial College London, St. Mary's Hospital, Norfolk Place, London, W2 1PG, UK. .,Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, Norfolk Place, London, W2 1PG, UK. .,Present address: Department of Pathology and Pathogen Biology, Centre for Emerging, Endemic and Exotic Diseases (CEEED), Royal Veterinary College, University of London, Hawkshead Campus, Herts, AL97TA, London, UK.
| | - Fiona M Fleming
- Schistosomiasis Control Initiative, Faculty of Medicine, Imperial College London, St. Mary's Hospital, Norfolk Place, London, W2 1PG, UK.
| | - Alan Fenwick
- Schistosomiasis Control Initiative, Faculty of Medicine, Imperial College London, St. Mary's Hospital, Norfolk Place, London, W2 1PG, UK.
| | | | | | - Amadou Garba
- Ministère de la Santé Publique (now WHO), Niamey, Niger. .,Present address: World Health Organization, 20, avenue Appia, 1211, Geneva 27, Switzerland.
| | | | | | - James Mwansa
- Department of Pathology and Microbiology, University of Zambia School of Medicine, University Teaching Hospital, Lusaka, Zambia.
| | - Lynsey Blair
- Schistosomiasis Control Initiative, Faculty of Medicine, Imperial College London, St. Mary's Hospital, Norfolk Place, London, W2 1PG, UK.
| | - Elisa Bosqué-Oliva
- Schistosomiasis Control Initiative, Faculty of Medicine, Imperial College London, St. Mary's Hospital, Norfolk Place, London, W2 1PG, UK. .,Present address: The END FUND, New York, NY, USA.
| | - Maria-Gloria Basáñez
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, Norfolk Place, London, W2 1PG, UK.
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Becker SL, Piraisoody N, Kramme S, Marti H, Silué KD, Panning M, Nickel B, Kern WV, Herrmann M, Hatz CF, N’Goran EK, Utzinger J, von Müller L. Real-time PCR for detection of Strongyloides stercoralis in human stool samples from Côte d'Ivoire: diagnostic accuracy, inter-laboratory comparison and patterns of hookworm co-infection. Acta Trop 2015. [PMID: 26215130 DOI: 10.1016/j.actatropica.2015.07.019] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Human infections with the helminth species Strongyloides stercoralis encompass a wide clinical spectrum, ranging from asymptomatic carriage to life-threatening disease. The diagnosis of S. stercoralis is cumbersome and the sensitivity of conventional stool microscopy is low. New molecular tools have been developed to increase sensitivity. We compared the diagnostic accuracy of real-time PCR with microscopy for the detection of S. stercoralis and hookworm in human stool samples, and investigated the inter-laboratory agreement of S. stercoralis-specific real-time PCR in two European laboratories. Stool specimens from 256 randomly selected individuals in rural Côte d'Ivoire were examined using three microscopic techniques (i.e. Kato-Katz, Koga agar plate (KAP) and Baermann (BM)). Additionally, ethanol-fixed stool aliquots were subjected to molecular diagnosis. The prevalence of S. stercoralis and hookworm infection was 21.9% and 52.0%, respectively, whilst co-infections were detected in 35 (13.7%) participants. The diagnostic agreement between real-time PCR and microscopy was excellent when both KAP and BM tested positive for S. stercoralis, but was considerably lower when only one microscopic technique was positive. The sensitivity of KAP, BM and real-time PCR for detection of S. stercoralis as compared to a combination of all diagnostic techniques was 21.4%, 37.5% and 76.8%, respectively. The inter-laboratory agreement of S. stercoralis-specific PCR was substantial (κ=0.63, p<0.001). We conclude that a combination of real-time PCR and stool microscopy shows high accuracy for S. stercoralis diagnosis. Besides high sensitivity, PCR may also enhance specificity by reducing microscopic misdiagnosis of morphologically similar helminth larvae (i.e. hookworm and S. stercoralis) in settings where both helminth species co-exist.
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Ruganuza DM, Mazigo HD, Waihenya R, Morona D, Mkoji GM. Schistosoma mansoni among pre-school children in Musozi village, Ukerewe Island, North-Western-Tanzania: prevalence and associated risk factors. Parasit Vectors 2015; 8:377. [PMID: 26178484 PMCID: PMC4504164 DOI: 10.1186/s13071-015-0997-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 07/09/2015] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Recent evidence indicates that pre-school children (PSC) living in S. mansoni highly endemic areas are at similar risk of schistosomiasis infection and morbidity as their school aged siblings. Recognizing this fact, the World Health Organization (WHO) is considering including this age group in highly endemic areas in control programmes using mass drug administration (MDA). However, detailed epidemiological information on S. mansoni infection among PSC is lacking for many endemic areas, specifically in Tanzania. This study was conducted to determine the prevalence of S. mansoni infection and its associated risk factors among PSC in Ukerewe Island, North-Western Tanzania. METHODS This was a cross-sectional study, which studied 400 PSC aged 1-6 years. The Kato-Katz (K-K) technique and the point of care circulating cathodic antigen (CCA) immunodiagnostic test were used to diagnose S. mansoni infection in stool and urine samples respectively. A pre-tested questionnaire was used to collect demographic data and water contact behaviour of the children from their parents/guardians. RESULTS Based on the K-K technique, 44.4% (95% CI: 39.4-49.4) pre-school children were infected with S. mansoni and the overall geometric mean eggs per gram of faeces (GM-epg) was 110.6 epg with 38.2 and 14.7% having moderate and heavy intensity infections respectively. Based on the CCA, 80.1%, (95% CI: 76.0-84.0) were infected if a trace was considered positive, and 45.9%, (95% CI: 40.9-50.9), were infected if a trace was considered negative. Reported history of lake visits (AOR = 2.31, 95% CI: 1.06-5.01, P < 0.03) and the proximity to the lake shore (<500 m) (AOR = 2.09, 95% CI: 1.05-4.14, P < 0.03) were significantly associated with S. mansoni infection. Reported lake visit frequency (4-7 days/week) was associated with heavy intensities of S. mansoni infection (P < 0.00). CONCLUSION The prevalence of S. mansoni infection in the study population using K-K and CCA-trace-negative was moderate. The frequency of lake visits and the proximity to the lake shore were associated with the infection of S. mansoni and its intensity. These findings call for the need to include the PSC in MDA programmes, public health education and provision of safe water for bathing.
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Affiliation(s)
- Deodatus M Ruganuza
- Department of Medical Parasitology and Entomology, School of Medicine, Catholic University of Health and Allied Sciences, P.O. Box 1464, Mwanza, Tanzania. .,Institute of Tropical Medicine and Infectious Diseases (ITROMID), Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62000-00200, Nairobi, Kenya.
| | - Humphrey D Mazigo
- Department of Medical Parasitology and Entomology, School of Medicine, Catholic University of Health and Allied Sciences, P.O. Box 1464, Mwanza, Tanzania.
| | - Rebecca Waihenya
- Department of Zoology, Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62000-00200, Nairobi, Kenya.
| | - Domenica Morona
- Department of Medical Parasitology and Entomology, School of Medicine, Catholic University of Health and Allied Sciences, P.O. Box 1464, Mwanza, Tanzania.
| | - Gerald M Mkoji
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute (KEMRI), PO Box 54840-00200, Nairobi, Kenya.
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Olliaro PL, Vaillant M, Diawara A, Coulibaly JT, Garba A, Keiser J, King CH, Knopp S, Landouré A, N’Goran EK, Raso G, Scherrer AU, Sousa-Figueiredo JC, Stete K, Zhou XN, Utzinger J. Toward Measuring Schistosoma Response to Praziquantel Treatment with Appropriate Descriptors of Egg Excretion. PLoS Negl Trop Dis 2015; 9:e0003821. [PMID: 26086551 PMCID: PMC4473103 DOI: 10.1371/journal.pntd.0003821] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2014] [Accepted: 05/10/2015] [Indexed: 01/05/2023] Open
Abstract
Background The control of schistosomiasis emphasizes preventive chemotherapy with praziquantel, which aims at decreasing infection intensity and thus morbidity in individuals, as well as transmission in communities. Standardizing methods to assess treatment efficacy is important to compare trial outcomes across settings, and to monitor program effectiveness consistently. We compared customary methods and looked at possible complementary approaches in order to derive suggestions for standardizing outcome measures. Methodology/Principal Findings We analyzed data from 24 studies conducted at African, Asian, and Latin American sites, enrolling overall 4,740 individuals infected with Schistosoma mansoni, S. haematobium, or S. japonicum, and treated with praziquantel at doses of 40–80 mg/kg. We found that group-based arithmetic and geometric means can be used interchangeably to express egg reduction rates (ERR) only if treatment efficacy is high (>95%). For lower levels of efficacy, ERR estimates are higher with geometric than arithmetic means. Using the distribution of individual responses in egg excretion, 6.3%, 1.7% and 4.3% of the subjects treated for S. haematobium, S. japonicum and S. mansoni infection, respectively, had no reduction in their egg counts (ERR = 0). The 5th, 10th, and 25th centiles of the subjects treated for S. haematobium had individual ERRs of 0%, 49.3%, and 96.5%; the corresponding values for S. japonicum were 75%, 99%, and 99%; and for S. mansoni 18.2%, 65.3%, and 99.8%. Using a single rather than quadruplicate Kato-Katz thick smear excluded 19% of S. mansoni-infected individuals. Whilst the effect on estimating ERR was negligible by individual studies, ERR estimates by arithmetic means were 8% lower with a single measurement. Conclusions/Significance Arithmetic mean calculations of Schistosoma ERR are more sensitive and therefore more appropriate to monitor drug performance than geometric means. However, neither are satisfactory to identify poor responders. Group-based response estimated by arithmetic mean and the distribution of individual ERRs are correlated, but the latter appears to be more apt to detect the presence and to quantitate the magnitude of suboptimal responses to praziquantel. To identify whether a person is infected with parasitic worms, stool or urine samples are examined for worm eggs. The drug praziquantel is used against the parasitic disease schistosomiasis. However, there is no definitive agreement as to how the efficacy of praziquantel is best expressed. We put together a database from various studies of the efficacy of praziquantel against schistosomiasis. Efficacy was measured using customary methods: cure rate (CR: percentage of people with eggs in their stool/urine before treatment who became egg-negative after treatment); and egg reduction rate (ERR; percentage reduction in the number of eggs in the stool/urine after treatment, where the mean number of eggs from all people treated is calculated using either geometric or arithmetic means). We found that arithmetic and geometric means can be used interchangeably only if treatment efficacy is very high; arithmetic means are more sensitive to capture drops in efficacy expressed by ERR. A valid complement for drug efficacy monitoring is to study the distribution of individual responses in egg excretion that allows identifying in a single measure both those who had an adequate response to treatment and those who respond less well; e.g., the 5% of the patients with the lowest ERRs.
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Affiliation(s)
- Piero L. Olliaro
- UNICEF/UNDP/World Bank/WHO Special Programme on Research and Training in Tropical Diseases (TDR), World Health Organization, Geneva, Switzerland
- Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- * E-mail:
| | - Michel Vaillant
- Centre of Competence for Methodology and Statistics (CCMS), Luxembourg Institute of Health (LIH), Strassen, Luxembourg
| | - Aïssatou Diawara
- Department of Biology, Division of Science and Mathematics, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Jean T. Coulibaly
- 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
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Amadou Garba
- University of Basel, Basel, Switzerland
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- Réseau International Schistosomoses, Environnement, Aménagement et Lutte (RISEAL-Niger), Niamey, Niger
| | - Jennifer Keiser
- Department of Medical Parasitology and Infection Biology, 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
| | - Stefanie Knopp
- University of Basel, Basel, Switzerland
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Aly Landouré
- Institut National de Recherche en Santé Publique, Bamako, Mali
| | - 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
- University of Basel, Basel, Switzerland
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, 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 Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Katarina Stete
- University of Basel, Basel, Switzerland
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- Center for Infectious Diseases and Travel Medicine, Department of Medicine, University Hospital Freiburg, Freiburg im Breisgau, Germany
| | - Xiao-Nong Zhou
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, People’s Republic of China
- Key Laboratory of Parasite and Vector Biology of the Chinese Ministry of Health, WHO Collaborating Center for Malaria, Schistosomiasis and Filariasis, Shanghai, People’s Republic of China
| | - Jürg Utzinger
- University of Basel, Basel, Switzerland
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
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Becker S, Chatigre J, Gohou JP, Coulibaly J, Leuppi R, Polman K, Chappuis F, Mertens P, Herrmann M, N'Goran E, Utzinger J, von Müller L. Combined stool-based multiplex PCR and microscopy for enhanced pathogen detection in patients with persistent diarrhoea and asymptomatic controls from Côte d’Ivoire. Clin Microbiol Infect 2015; 21:591.e1-10. [DOI: 10.1016/j.cmi.2015.02.016] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 02/06/2015] [Accepted: 02/19/2015] [Indexed: 02/04/2023]
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Sanya RE, Muhangi L, Nampijja M, Nannozi V, Nakawungu PK, Abayo E, Webb EL, Elliott AM. Schistosoma mansoni and HIV infection in a Ugandan population with high HIV and helminth prevalence. Trop Med Int Health 2015; 20:1201-1208. [PMID: 25976017 PMCID: PMC4568314 DOI: 10.1111/tmi.12545] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Objectives Recent reports suggest that Schistosoma infection may increase the risk of acquiring human immunodeficiency virus (HIV). We used data from a large cross‐sectional study to investigate whether Schistosoma mansoni infection is associated with increased HIV prevalence. Methods We conducted a household survey of residents in island fishing communities in Mukono district, Uganda, between October 2012 and July 2013. HIV status was assessed using rapid test kits. Kato‐Katz (KK) stool tests and urine‐circulating cathodic antigen (CCA) were used to test for Schistosoma infection. Multivariable logistic regression, allowing for the survey design, was used to investigate the association between S. mansoni infection and HIV infection. Results Data from 1412 participants aged 13 years and older were analysed (mean age 30.3 years, 45% female). The prevalence of HIV was 17.3%. Using the stool Kato‐Katz technique on a single sample, S. mansoni infection was detected in 57.2% (719/1257) of participants; urine CCA was positive in 73.8% (478/650) of those tested. S. mansoni infection was not associated with HIV infection. [KK (aOR = 1.04; 95% CI: 0.74–1.47, P = 0.81), CCA (aOR = 1.53; 95% CI: 0.78–3.00, P = 0.19)]. The median S. mansoni egg count per gram was lower in the HIV‐positive participants (P = 0.005). Conclusions These results add to the evidence that S. mansoni has little effect on HIV transmission, but may influence egg excretion.
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Affiliation(s)
- Richard E Sanya
- Medical Research Council/UVRI Uganda Research Unit on AIDS, Entebbe, Uganda
| | - Lawrence Muhangi
- Medical Research Council/UVRI Uganda Research Unit on AIDS, Entebbe, Uganda
| | - Margaret Nampijja
- Medical Research Council/UVRI Uganda Research Unit on AIDS, Entebbe, Uganda
| | | | | | | | - Emily L Webb
- London School of Hygiene & Tropical Medicine, London, UK
| | - Alison M Elliott
- Medical Research Council/UVRI Uganda Research Unit on AIDS, Entebbe, Uganda.,London School of Hygiene & Tropical Medicine, London, UK
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