scholarly journals Application of Schistosomiasis Consortium for Operational Research and Evaluation Study Findings to Refine Predictive Modeling of Schistosoma mansoni and Schistosoma haematobium Control in Sub-Saharan Africa

2020 ◽  
Vol 103 (1_Suppl) ◽  
pp. 97-104 ◽  
Author(s):  
Charles H. King ◽  
Nara Yoon ◽  
Xiaoxia Wang ◽  
Nathan C. Lo ◽  
Ramzi Alsallaq ◽  
...  
Keyword(s):  
Schistosoma Mansoni ◽  
Predictive Modeling ◽  
Schistosoma Haematobium ◽  
Operational Research ◽  
Evaluation Study ◽  
Sub Saharan Africa ◽  
Sub Saharan

IL-15 as an Immune Modulator in Schistosomiasis

2019 ◽  
Vol 152 (Supplement_1) ◽  
pp. S102-S103
Author(s):  
Mary Reust
Keyword(s):  
Schistosoma Mansoni ◽  
Mucosal Immunity ◽  
Peripheral Blood ◽  
Schistosoma Haematobium ◽  
Sub Saharan Africa ◽  
Immune Modulator ◽  
Sub Saharan ◽  
Negative Controls

Abstract Introduction Schistosomiasis affects approximately 200,000,000 people globally, with 93% of these cases in sub-Saharan Africa. Women who have been infected with Schistosoma haematobium have four times the risk of contracting HIV due to a change in their cervical mucosal immunity. The mechanism for this altered cervical mucosal immunity was not understood until a recent study published by Downs et al, which showed IL-15 levels were significantly lower in cervicovaginal lavage fluid samples of women with Schistosoma haematobium. Schistosoma mansoni, known to cause intestinal schistosomiasis, has also shown the potential to increase the risk of contracting HIV. The objective for this study is to see if IL-15 levels in peripheral blood are significantly different between patients positive for S mansoni and negative controls. Methods Enzyme-linked immunosorbent assays (BD Biosciences, San Jose, CA) for IL-15 were performed on plasma collected from 84 patients in villages in sub-Saharan Africa. These samples were collected at screening, 3-month follow-up, 6-month follow-up, and 9-month follow-up appointments. Results Of 249 plasma samples tested, 20 had detectable IL-15 levels ranging from 8.329 pg/mL to above the upper limit of detection of 500 pg/mL. While the patients that had detectable IL-15 in the peripheral blood were half S mansoni negative and half S mansoni positive, when an S mansoni–positive patient was positive for IL-15, it was across all timepoints. Conclusion The role of IL-15 as an immune modulator can explain the elevated levels in S mansoni–positive patients. All patients in the study were tested for significant comorbidities, with no correlation seen within the negative controls. Further testing is needed to investigate the role of IL-15 in the alteration of localized areas of infection with both Schistosoma mansoni and Schistosoma haematobium. More samples are currently being collected from the patient population in Tanzania, and future studies are planned.

scholarly journals High prevalence of Schistosoma haematobium × Schistosoma bovis hybrids in schoolchildren in Côte d'Ivoire

Parasitology ◽  
2019 ◽  
Vol 147 (3) ◽  
pp. 287-294 ◽  
Author(s):  
Etienne K. Angora ◽  
Jean-François Allienne ◽  
Olivier Rey ◽  
Hervé Menan ◽  
André O. Touré ◽  
...  
Keyword(s):  
Cote D'ivoire ◽  
Schistosoma Haematobium ◽  
Côte D’Ivoire ◽  
Sub Saharan Africa ◽  
Cote D’Ivoire ◽  
Mitochondrial Cox1 ◽  
Fta Cards ◽  
Côte D'ivoire ◽  
High Prevalence ◽  
Sub Saharan

AbstractSchistosomiasis is a neglected tropical disease, though it is highly prevalent in many parts of sub-Saharan Africa. While Schistosoma haematobium-bovis hybrids have been reported in West Africa, no data about Schistosoma hybrids in humans are available from Côte d'Ivoire. This study aimed to identify and quantify S. haematobium-bovis hybrids among schoolchildren in four localities of Côte d'Ivoire. Urine samples were collected and examined by filtration to detect Schistosoma eggs. Eggs were hatched and 503 miracidia were individually collected and stored on Whatman® FTA cards for molecular analysis. Individual miracidia were molecularly characterized by analysis of mitochondrial cox1 and nuclear internal transcribed spacer 2 (ITS 2) DNA regions. A mitochondrial cox1-based diagnostic polymerase chain reaction was performed on 459 miracidia, with 239 (52.1%) exhibiting the typical band for S. haematobium and 220 (47.9%) the S. bovis band. The cox1 and ITS 2 amplicons were Sanger sequenced from 40 randomly selected miracidia to confirm species and hybrids status. Among the 33 cox1 sequences analysed, we identified 15 S. haematobium sequences (45.5%) belonging to seven haplotypes and 18 S. bovis sequences (54.5%) belonging to 12 haplotypes. Of 40 ITS 2 sequences analysed, 31 (77.5%) were assigned to pure S. haematobium, four (10.0%) to pure S. bovis and five (12.5%) to S. haematobium-bovis hybrids. Our findings suggest that S. haematobium-bovis hybrids are common in Côte d'Ivoire. Hence, intense prospection of domestic and wild animals is warranted to determine whether zoonotic transmission occurs.

scholarly journals Evaluating survey designs for targeting preventive chemotherapy against Schistosoma haematobium and Schistosoma mansoni across Sub-Saharan Africa: a geostatistical analysis and modelling study

2020 ◽  
Author(s):  
Kimberly Fornace ◽  
Claudio Fronterrè ◽  
Fiona M Fleming ◽  
Hope Simpson ◽  
Honorat Zoure ◽  
...  
Keyword(s):  
Cost Effectiveness ◽  
Schistosoma Haematobium ◽  
Sampling Strategy ◽  
Sub Saharan Africa ◽  
Spatial Distributions ◽  
Preventive Chemotherapy ◽  
School Based ◽  
Control Programmes ◽  
Sub Saharan ◽  
Survey Designs

Abstract Background: Schistosomiasis control programmes primarily use school-based surveys to identify areas for mass drug administration of preventive chemotherapy. However, as the spatial distribution of schistosomiasis can be highly focal, transmission may not be detected by surveys implemented at districts or larger spatial units. Improved mapping strategies are required to accurately and cost-effectively target preventive chemotherapy to remaining foci across all possible spatial distributions of schistosomiasis. Methods: Here, we use geostatistical models to quantify the spatial heterogeneity of Schistosoma haematobium and S. mansoni across sub-Saharan Africa using the most comprehensive dataset available on school-based surveys. Applying this information to parameterise simulations, we assess the accuracy and cost of targeting alternative implementation unit sizes across the range of plausible schistosomiasis distributions. We evaluate the consequences of decisions based on survey designs implemented at district and subdistrict levels sampling different numbers of schools. Cost data were obtained from field surveys conducted across multiple countries and years, with cost effectiveness evaluated as the cost per correctly identified school. Results: Models identified marked differences in prevalence and spatial distributions between countries and species; however, results suggest implementing surveys at subdistrict level increase the accuracy of treatment classifications across most scenarios. While sampling intensively at the subdistrict level resulted in the highest classification accuracy, this sampling strategy resulted in the highest costs. Alternatively, sampling the same numbers of schools currently recommended at the district level but stratifying by subdistrict increased cost effectiveness.Conclusions: This study provides a new tool to evaluate schistosomiasis survey designs across a range of transmission settings. Results highlight the importance of considering spatial structure when designing sampling strategies, illustrating that a substantial proportion of children may be undertreated even when an implementation unit is correctly classified. Control programmes need to weigh the increased accuracy of more detailed mapping strategies against the survey costs and treatment priorities.

scholarly journals The HIV/AIDS epidemic in sub-Saharan Africa: thinking ahead on programmatic tasks and related operational research

2011 ◽  
Vol 14 ◽  
pp. S7-S7 ◽  
Author(s):  
Rony Zachariah ◽  
Wim Van Damme ◽  
Vic Arendt ◽  
Jean Claude Schmit ◽  
Anthony D Harries
Keyword(s):  
Operational Research ◽  
Sub Saharan Africa ◽  
Aids Epidemic ◽  
Sub Saharan ◽  
Hiv Aids

scholarly journals Effect of Phenotypic Screening of Extracts and Fractions of Erythrophleum ivorense Leaf and Stem Bark on Immature and Adult Stages of Schistosoma mansoni

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Gertrude Kyere-Davies ◽  
Christian Agyare ◽  
Yaw Duah Boakye ◽  
Brian M. Suzuki ◽  
Conor R. Caffrey
Keyword(s):  
Schistosoma Mansoni ◽  
Petroleum Ether ◽  
Developmental Stages ◽  
Stem Bark ◽  
Current Treatment ◽  
Sub Saharan Africa ◽  
Bark Extract ◽  
Phenotypic Screening ◽  
Sub Saharan ◽  
New Treatments

Schistosomiasis is a disease caused by a flatworm parasite that infects people in tropical and subtropical regions of Sub-Saharan Africa, South America, China, and Southeast Asia. The reliance on just one drug for current treatment emphasizes the need for new chemotherapeutic strategies. The aim of this study was to determine the phenotypic effects of extracts and fractions of leaf and stem bark of Erythrophleum ivorense (family Euphorbiaceae), a tree that grows in tropical parts of Africa, on two developmental stages of Schistosoma mansoni, namely, postinfective larvae (schistosomula or somules) and adults. Methanol leaf and stem bark extracts of E. ivorense were successively fractionated with acetone, petroleum ether, ethyl acetate, and methanol. These fractions were then incubated with somules at 0.3125 to 100 μg/mL and with adults at 1.25 μg/mL. The acetone fractions of both the methanol leaf and bark of E. ivorense were most active against the somules whereas the petroleum ether fractions showed least activity. For adult parasites, the acetone fraction of methanol bark extract also elicited phenotypic changes. The data arising provide the first step in the discovery of new treatments for an endemic infectious disease using locally sourced African medicinal plants.

scholarly journals When Should the Emphasis on Schistosomiasis Control Move to Elimination?

2018 ◽  
Vol 3 (3) ◽  
pp. 85 ◽  
Author(s):  
W. Secor ◽  
Daniel Colley
Keyword(s):  
South America ◽  
Operational Research ◽  
Sub Saharan Africa ◽  
World Health ◽  
Evidence Based ◽  
Clean Water ◽  
Schistosomiasis Control ◽  
The World ◽  
The Caribbean ◽  
Sub Saharan

The stated goal of the World Health Organization’s program on schistosomiasis is paraphrased as follows: to control morbidity and eliminate transmission where feasible. Switching from a goal of controlling morbidity to interrupting transmission may well be currently feasible in some countries in the Caribbean, some areas in South America, northern Africa, and selected endemic areas in sub-Saharan Africa where there have been improvements in sanitation and access to clean water. However, in most of sub-Saharan Africa, where programmatic interventions still consist solely of annual mass drug administration, such a switch in strategies remains premature. There is a continued need for operational research on how best to reduce transmission to a point where interruption of transmission may be achievable. The level of infection at which it is feasible to transition from control to elimination must also be defined. In parallel, there is also a need to develop and evaluate approaches for achieving and validating elimination. There are currently neither evidence-based methods nor tools for breaking transmission or verifying that it has been accomplished. The basis for these statements stems from numerous studies that will be reviewed and summarized in this article; many, but not all of which were undertaken as part of SCORE, the Schistosomiasis Consortium for Operational Research and Evaluation.

Molecular epidemiology and phylogeography of Schistosoma mansoni around Lake Victoria

Parasitology ◽  
2010 ◽  
Vol 137 (13) ◽  
pp. 1937-1949 ◽  
Author(s):  
C. J. STANDLEY ◽  
N. B. KABATEREINE ◽  
C. N. LANGE ◽  
N. J. S. LWAMBO ◽  
J. R. STOTHARD
Keyword(s):  
Population Genetics ◽  
Schistosoma Mansoni ◽  
Molecular Epidemiology ◽  
Lake Victoria ◽  
Public Health Problem ◽  
Human Migration ◽  
Sub Saharan Africa ◽  
Major Public Health Problem ◽  
Sub Saharan ◽  
Coi Sequences

SUMMARYIntestinal schistosomiasis continues to be a major public health problem in sub-Saharan Africa, and is endemic in communities around Lake Victoria. Interest is growing in the molecular evolution and population genetic structure of Schistosoma mansoni and we describe a detailed analysis of the molecular epidemiology and phylogeography of S. mansoni from Lake Victoria. In total, 388 cytochrome oxidase 1 (COI) sequences were obtained from 25 sites along the Ugandan, Tanzanian and Kenyan shorelines of Lake Victoria, and 122 unique barcodes were identified; 9 corresponded to previously discovered barcodes from Lakes Victoria and Albert. A subset of the data, composed of COI sequences from miracidia from 10 individual children, was used for population genetics analyses; these results were corroborated by microsatellite analysis of 4 isolates of lab-passaged adult worms. Overall, 12 barcodes were found to be shared across all 3 countries, whereas the majority occurred singly and were locally restricted. The population genetics analyses were in agreement in revealing high diversity at the level of the human host and negligible population structuring by location. The lack of correlation between genetic distance and geographical distance in these data may be attributed to the confounding influence of high intra-individual diversity as well as human migration between communities.

scholarly journals Three monthly doses of 60 mg/kg praziquantel for Schistosoma haematobium infection is a safe and effective treatment regimen.

2020 ◽  
Author(s):  
Samuel Nkansah Darko ◽  
Henry Hanson ◽  
Sampson Twumasi Ankrah ◽  
Sandra Baffour ◽  
Priscilla Adjei-Kusi ◽  
...  
Keyword(s):  
Renal Function ◽  
Schistosoma Haematobium ◽  
Post Treatment ◽  
Sub Saharan Africa ◽  
Gamma Glutamyl Transferase ◽  
Disease Epidemiology ◽  
Sub Saharan ◽  
Pre Treatment ◽  
And Gender ◽  
Glutamyl Transferase

Abstract Background Praziquantel (PZQ) is the standard treatment for Schistosomiasis in sub-Saharan Africa. However, there is evidence suggesting praziquantel treatment failure in Schistosome infections with associated potential renal impairment. The objective of this study was to determine the effect of three monthly doses of 60 mg/kg/day PZQ on schistosome egg count, liver and renal function during the treatment of urinary schistosomiasis in Ghana. Methods A nested case-control study was designed from a cohort screened for schistosomiasis; 28 schistosomiasis positive cases by microscopy matched with 53 healthy controls by age and gender. The study population was urban dwellers from the Asokwa sub-metropolitan area, Kumasi in Ghana. Participants were within the age range of 6 to 30 years. We assessed Schistosoma haematobium egg counts in urine and its associated impact on liver and renal function at baseline, treatment and post-treatment phases using serum. Results Of the 28 cases and 53 controls, 78.6% and (81.1% were males respectively. Globulin levels before treatment was higher in cases [36.7 (32.8, 40.1) vrs 30.5 (22.4, 33.8) , p=0.005] at pre-treatment but not at post-treatment [35.8 (31.2, 39.1)vrs 37.4 (29.7, 43.0), p= 0.767]. Estimated cure rate was 42.9%, 46.4% and 96.4% after first, second and third dose respectively. Schistosome egg counts dropped significantly (p= 0.001) from before second dose to post-treatment. Similarly, levels of alanine aminotransferase (p=0.001), aspartate aminotransferase (p=0.028) and gamma glutamyl transferase (p=0.001) significantly declined towards post-treatment. Estimated glomerular filtration rate significantly improved from before second dose to post-treatment using both the Chronic Kidney Disease Epidemiology Program (p=0.001) and 4-variable Modification of Diet in Renal Disease (p=0.002) equations. Conclusion Treatment of urinary Schistosoma hematobium infections with a repeated high monthly dose of 60 mg/kg of praziquantel for 3 months is safe and effective.

scholarly journals Mini-FLOTAC as an alternative, non-invasive diagnostic tool for Schistosoma mansoni and other trematode infections in wildlife reservoirs

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Stefano Catalano ◽  
Amelia Symeou ◽  
Kirsty J. Marsh ◽  
Anna Borlase ◽  
Elsa Léger ◽  
...  
Keyword(s):  
Schistosoma Mansoni ◽  
Sub Saharan Africa ◽  
Health Concern ◽  
Post Mortem ◽  
Post Mortem Examination ◽  
Non Invasive ◽  
Flotac Technique ◽  
Endemic Areas ◽  
Sub Saharan ◽  
Trematode Infections

Abstract Background Schistosomiasis and food-borne trematodiases are not only of major public health concern, but can also have profound implications for livestock production and wildlife conservation. The zoonotic, multi-host nature of many digenean trematodes is a significant challenge for disease control programmes in endemic areas. However, our understanding of the epidemiological role that animal reservoirs, particularly wild hosts, may play in the transmission of zoonotic trematodiases suffers a dearth of information, with few, if any, standardised, reliable diagnostic tests available. We combined qualitative and quantitative data derived from post-mortem examinations, coprological analyses using the Mini-FLOTAC technique, and molecular tools to assess parasite community composition and the validity of non-invasive methods to detect trematode infections in 89 wild Hubert’s multimammate mice (Mastomys huberti) from northern Senegal. Results Parasites isolated at post-mortem examination were identified as Plagiorchis sp., Anchitrema sp., Echinostoma caproni, Schistosoma mansoni, and a hybrid between Schistosoma haematobium and Schistosoma bovis. The reports of E. caproni and Anchitrema sp. represent the first molecularly confirmed identifications for these trematodes in definitive hosts of sub-Saharan Africa. Comparison of prevalence estimates derived from parasitological analysis at post-mortem examination and Mini-FLOTAC analysis showed non-significant differences indicating comparable results between the two techniques (P = 1.00 for S. mansoni; P = 0.85 for E. caproni; P = 0.83 for Plagiorchis sp.). A Bayesian model, applied to estimate the sensitivities of the two tests for the diagnosis of Schistosoma infections, indicated similar median posterior probabilities of 83.1% for Mini-FLOTAC technique and 82.9% for post-mortem examination (95% Bayesian credible intervals of 64.0–94.6% and 63.7–94.7%, respectively). Conclusions Our results showed that the Mini-FLOTAC could be applied as an alternative diagnostic technique for the detection of the zoonotic S. mansoni and other trematodes in rodent reservoirs. The implementation of non-invasive diagnostics in wildlife would offer numerous advantages over lethal sampling methodologies, with potential impact on control strategies of zoonotic helminthiases in endemic areas of sub-Saharan Africa and on fostering a framework of animal use reduction in scientific practice.

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