The Road to Elimination: Current State of Schistosomiasis Research and Progress Towards the End Game

Evaluation of molecular and serological testing for imported urogenital schistosomiasis screening in a referral tropical medicine centre in Barcelona, Spain

BACKGROUND

Schistosomiasis, a major neglected tropical disease, is caused by Schistosoma spp. It is estimated that more than 200 million people are affected worldwide, mostly in Africa. The gold standard diagnosis of urogenital schistosomiasis (UGS) is the microscopic visualisation of Schistosoma haematobium eggs in concentrated urine; however, its sensitivity is low. This study aimed to evaluate the effectiveness of molecular and serological testing for imported UGS screening in asymptomatic sub-Saharan migrants in a non-endemic setting.

METHODS

A retrospective cross-sectional study between November 2021 and December 2022 was conducted by collecting demographic, clinical and laboratory data from the medical records of migrants from endemic areas screened for UGS at the International Health Unit Vall d'Hebron-Drassanes, Barcelona, Spain. Urine samples were analysed by real-time PCR for S. haematobium DNA and by microscopy for egg detection. Serum samples were tested using a serological assay based on enzyme-linked immunosorbent assay (ELISA). UGS was confirmed by a positive result in real-time PCR and/or microscopy, while possible UGS was defined as a case with only a positive serological result.

RESULTS

A total of 604 patients were included in this study; 32 out of 604 (5.3%) urine samples were positive for S. haematobium by real-time PCR and/or microscopy examination (confirmed UGS cases). Schistosoma haematobium DNA was detected in 28/604 (4.6%) urine samples, while eggs were visualised in 24/604 (3.9%), with 12 discordant cases between both techniques. Real-time PCR demonstrated a sensitivity of 83.3%, a specificity of 98.6%, and a kappa value of 0.76. Serology was performed in 529/604 cases and exhibited lower specificity, 70.87% (kappa value 0.26). Other laboratory parameters such as leukocyturia, microhaematuria, eosinophilia and elevated IgE were significantly associated with UGS diagnosis.

CONCLUSIONS

Real-time PCR proved to be more sensitive than microscopy for diagnosing imported UGS in non-endemic settings, with minimal discordance between methods. The serological test exhibited very low specificity and high sensitivity rates, suggesting its usefulness as a screening test among high-risk populations in non-endemic settings.

Navigating the Parasitic Landscape: Insights into Infection Patterns and Public Health Strategies in West Africa

Parasitic infections remain a significant public health challenge in West Africa, contributing to high morbidity and mortality rates, economic burdens, and healthcare system strain. Malaria, soil-transmitted helminths, schistosomiasis, and other parasitic diseases persist due to environmental, socio-economic, and healthcare barriers. A systematic literature search was conducted using databases such as PubMed, Scopus, Web of Science, and Science Direct. Studies published between 2014 and 2024 were screened using predefined eligibility criteria. Cross-sectional and case-control studies reporting on prevalence, diagnostic techniques, and treatment of parasitic infections in West Africa were included. The Rayyan online platform was used for screening, and data extraction focused on study location, prevalence rates, diagnostic methods, and treatment regimens. This review identified the high prevalence rates of malaria, schistosomiasis, and soil-transmitted helminths across various West African countries. Co-infections were frequently reported, particularly among children and pregnant women. Diagnostic methods ranged from traditional microscopy to advanced molecular techniques, though accessibility remained a challenge in resource-limited settings. Treatment strategies, including artemisinin-based combination therapies for malaria and mass drug administration for helminths, showed varying efficacy due to reinfection risks and emerging drug resistance. Factors influencing transmission included environmental conditions, sanitation practices, socio-economic status, and healthcare access. Parasitic infections in West Africa continue to pose significant health and economic challenges. Integrated control programs, enhanced surveillance systems, improved access to diagnostics and treatment, and targeted public health interventions are essential for reducing disease burden. Further research is needed to evaluate the long-term impact of existing interventions and explore innovative solutions for parasite control and elimination.

Human schistosomiasis

Schistosomiasis is a neglected tropical disease caused by infection with blood flukes of the genus Schistosoma. Widely distributed in the Middle East, southeast Asia, Latin America, and (mostly) sub-Saharan Africa, schistosomiasis is acquired upon skin penetration of infective larvae released by freshwater snails. Acute infection might present with self-limiting hypersensitivity reactions (known as Katayama fever). Chronic infection typically leads to two main clinical patterns: intestinal or urogenital schistosomiasis, depending on the infecting species. Impairment of other body sites (eg, the CNS or respiratory tract) can occur. The intestinal form is characterised by abdominal pain and diarrhoea, with or without blood; complications are hepatic fibrosis, portal hypertension, splenomegaly, and variceal bleeding. The urogenital form is characterised by dysuria and haematuria; complications are renal failure and squamous-cell carcinoma of the bladder. Conventional diagnosis is based on egg detection in faeces or urine, although sensitivity might be low. Praziquantel is the first-line treatment, and it is also provided in preventive chemotherapy campaigns by mass drug administration to afflicted communities.

Schistosomiasis Burden and Trend Analysis in Africa: Insights from the Global Burden of Disease Study 2021

Schistosomiasis remains a major public health concern in Africa, despite global efforts to eliminate the disease by 2030. This study estimates the burden, trends, and inequalities of schistosomiasis in Africa from 1990 to 2021, and projects future prevalence to inform the WHO's elimination strategies. Data from the Global Burden of Disease Study (GBD 2021) were used to calculate annual average percentage change (AAPC) and annual percentage change (APC), with spatial global autocorrelation analysis performed to examine temporal and spatial trends. Five modeling algorithms were constructed to predict disease burden in Africa from 2022 to 2041. The age-standardized prevalences rate (ASPR) of schistosomiasis in Africa decreased from 18,495.51 per 100,000 in 1990 to 9,461.76 per 100,000 in 2021. The total number of cases, disability-adjusted life-years (DALYs), and mortality accounted for 84.25%, 87.92% and 87.28% of the global totals, respectively. ARIMA modeling predicts that by 2030, the ASPR will reach 3.99%. Despite progress, the burden remains significant, and intensified efforts are needed, particularly in high-burden regions like West Africa, to meet the WHO's 2030 elimination targets.

Diagnostic, prognostic, and therapeutic potentials of gut microbiome profiling in human schistosomiasis: A comprehensive systematic review

BACKGROUND

Several studies have highlighted alteration in the gut microbiome associated with the onset and progression of diseases. Recognizing the potential of gut microbiota as biomarkers, this systematic review seeks to synthesize current data on the intricate relationship between the host gut microbiome profiles and their usefulness for the development of diagnostic, prognostic and therapeutic approaches to control human schistosomiasis.

METHODS

A systematic literature review was carried out by searching for relevant studies published until date, that is May 2024, using Medline, Embase, Global Health, Web of Science, and Global Index Medicus databases. The keywords used to select articles were "Gut microbiome", "Gut Microbiota", "Schistosomiasis", "Bilharziasis ", and "Human". Extracted data were analysed qualitatively from the selected articles.

RESULTS

Of the 885 articles retrieved and screened, only 13 (1.47%) met the inclusion criteria and were included in this review. Of the included studies, 6 (46.2%) explored alterations of gut microbiome in schistosome-infected patients, 4 (30.7%) in patients with liver pathologies, and 3 (23.1%) in patients treated with praziquantel. Bacteria from the genera Bacteroides, Faecalibacterium, Blautia and Megasphaera were associated with S. japonicum and S. haematobium infection in school-aged children, whereas infection with S. mansoni rather associated with Klebsiella and Enterobacter. The gut microbiota signature in patient with schistosomiasis-induced liver pathology was reported only for S. japonicum, and the genus Prevotella appeared as a non-invasive biomarker of S. japonicum-associated liver fibrosis. For S. mansoni-infected school-aged children, it further appeared that the treatment outcome following praziquantel administration associated with the abundance in the gut microbiome of bacteria from the classes Fusobacteriales, Rickettsiales and Neisseriales.

CONCLUSION

The host gut microbiome appears to be a valuable, non-invasive, but still poorly utilized, source of host biomarkers potentially informative for better diagnosing, prognosing and treating schistosomiasis. Further studies are therefore needed to comprehensively define such gut microbial biomarkers of human schistosomiasis and catalyse the informed development of gut microbiome-based tools of schistosomiasis control.

Schistosomiasis Chemotherapy, Chemoprevention, and Vaccines: History, Progress, and Priorities

BACKGROUND

Schistosomiasis is a major human disease of public health importance. Freshwater snails serving as intermediary hosts and human interaction with surface water tainted by feces or urine are both necessary components of the transmission cycle. Schistosoma haematobium, Schistosoma mansoni, and Schistosoma japonicum are the primary pathogen species. Over 250 million individuals are infected globally, according to the World Health Organization, causing significant morbidity and an estimated loss of 1.9 million disability-adjusted life years, a number that is probably underestimated. Immunological protection is slowly built up through complex immunological systems, although innate factors also play a role. Chronic schistosomiasis affects mainly individuals residing in poor rural area. Vaccination is considered as one of the most sustainable options for the control of any pathogen, but schistosomiasis vaccine for humans or animals is not available till now despite the discovery of numerous potentially promising schistosome vaccine antigens.

OBJECTIVE

To provide an overview of the schistosomiasis chemotherapy, chemoprevention, and vaccines history and progress.

DESIGN

Review article.

DATA SOURCES

PubMed, ISI Web of Science, Science Direct, and the World Health Organization database.

CONCLUSION

Favorably praziquantel (PZQ) is a medication with excellent chemopreventive treatment compliance. Due to the extensive usage of PZQ, there is a great deal of debate surrounding the emergence of drug resistance. PZQ is effective against all species of schistosomes, schistosomiasis prevalence has remained largely unaffected, due to reinfection in high transmission areas and growing juvenile worms that were not affected by the drug, even though the need for a schistosomiasis vaccine is even more pressing.

Schistosomiasis-Microbiota Interactions: A Systematic Review and Meta-Analysis

INTRODUCTION

Schistosomiasis, a tropical disease affecting humans and animals, affected 251.4 million people in 2021. Schistosoma mansoni, S. haematobium, S. intercalatum, and S. japonicum are primary human schistosomes, causing tissue damage, granulomas, ulceration, hemorrhage, and opportunistic pathogen entry. The gut and urinary tract microbiota significantly impact a host's susceptibility to schistosomiasis, disrupting microbial balance; however, this relationship is not well understood. This systematic review and meta-analysis explores the intricate relationship between schistosomiasis and the host's microbiota, providing crucial insights into disease pathogenesis and management.

METHODS

This systematic review used PRISMA guidelines to identify peer-reviewed articles on schistosomiasis and its interactions with the host microbiome, using multiple databases and Google Scholar, providing a robust dataset for analysis. The study utilized Meta-Mar v3.5.1; descriptive tests, random-effects models, and subgroups were analyzed for the interaction between Schistosomiasis and the microbiome. Forest plots, Cochran's Q test, and Higgins' inconsistency statistic (I2) were used to assess heterogeneity.

RESULTS

The human Schistosoma species were observed to be associated with various bacterial species isolated from blood, stool, urine, sputum, skin, and vaginal or cervical samples. A meta-analysis of the interaction between schistosomiasis and the host microbiome, based on 31 studies, showed 29,784 observations and 5871 events. The pooled estimates indicated a significant association between schistosomiasis and changes in the microbiome of infected individuals. There was considerable heterogeneity with variance effect sizes (p < 0.0001). Subgroup analysis of Schistosoma species demonstrated that S. haematobium was the most significant contributor to the overall heterogeneity, accounting for 62.1% (p < 0.01). S. mansoni contributed 13.0% (p = 0.02), and the coinfection of S. haematobium and S. mansoni accounted for 16.8% of the heterogeneity (p < 0.01), contributing to the variability seen in the pooled analysis. Similarly, praziquantel treatment (RR = 1.68, 95% CI: 1.07-2.64) showed high heterogeneity (Chi2 = 71.42, df = 11, p < 0.01) and also indicated that Schistosoma infections in males (RR = 1.46, 95% CI: 0.00 to 551.30) and females (RR = 2.09, 95% CI: 0.24 to 18.31) have a higher risk of altering the host microbiome.

CONCLUSIONS

Schistosomiasis significantly disrupts the host microbiota across various bodily sites, leading to increased susceptibility to different bacterial taxa such as E. coli, Klebsiella, Proteus, Pseudomonas, Salmonella, Staphylococcus, Streptococcus, and Mycobacterium species (M. tuberculosis and M. leprae). This disruption enables these bacteria to produce toxic metabolites, which in turn cause inflammation and facilitate the progression of disease. The impact of schistosomiasis on the vaginal microbiome underscores the necessity for gender-specific approaches to treatment and prevention. Effective management of female genital schistosomiasis (FGS) requires addressing both the parasitic infection and the resulting microbiome imbalances. Additionally, praziquantel-treated individuals have different microbiome compositions compared to individuals with no praziquantel treatment. This suggests that combining praziquantel treatment with probiotics could potentially decrease the disease severity caused by an altered microbiome.

Time-course whole blood transcriptome profiling provides new insights into Microtus fortis natural resistance mechanism to Schistosoma japonicum

Microtus fortis is known as a non-susceptible animal host of S. japonicum. A better understanding of this animal immune defense mechanism during the early stage of infection may offer an alternative route for vaccine development or therapy. Here, we analyzed the whole blood transcriptome of M. fortis using next-generation sequencing (NGS) to identify immune genes of biological relevance that might be involved in the mechanism of its resistance. The blood samples were collected from uninfected animals (control group) and infected animals at different time points (3, 7, 10 and 14 days post-infection). We identified 5310 sequences as unigenes and successfully annotated 4636 of them. The immune response was more intense at 10 dpi. The upregulated genes at this time point were mainly activated in the TNF and NF-kappa B signaling pathways, Th1, Th2and Th17 cell differentiation as well as cytokine-cytokine receptor interaction. Based on the differentially expressed genes analysis, we report that the IF27L2B, RETN, PGRP, IFI35, TYROBP, S100A8, S100A11, CD162, CD88, CYBA, and LBP could play important roles in the mechanism of M. fortis resistance.

Schistosomiasis in the Military-A Narrative Review

Schistosomiasis is a parasitosis caused by trematodes of the genus Schistosoma. Humans are infected when coming into contact with freshwater containing the parasites' infective stages, which are amplified through freshwater-dwelling snails acting as intermediate hosts. Schistosomiasis has posed significant problems for troops exposed to freshwater in endemic regions ever since the Napoleonic wars. Schistosomiasis has substantial differences in clinical presentation, depending on the type of parasite, intensity of infection and reinfection, clinical form, and disease stage. It can remain undiagnosed for long periods of time, with well-known long-term morbidity and mortality risks. The diagnosis of schistosomiasis depends on its stage and relays on several tests, all with limitations in sensitivity and specificity. The diagnostic gold standard is the detection of eggs in urine, feces, or tissue biopsies, but this can raise problems in patients such as military personnel, in which the worm burden is usually low. Praziquantel is the drug of choice for schistosomiasis. Currently, there is no available commercial vaccine against any Schistosoma parasite. Avoiding freshwater exposure is the best prevention. Herein, we review the clinical presentation, diagnosis, treatment, and prevention of schistosomiasis in the military. This information may decrease the impact of schistosomiasis on this particular professional group.

Schistosomiasis endemicity and its role in sexually transmitted infections - a systematic review and meta-analysis

Introduction

Schistosomiasis, a tropical parasitic disease, affects 779 million people globally, with 85% of cases in Africa. The interplay between schistosomiasis and other sexually transmitted infections (STIs) can exacerbate health burdens, but most attention has focused on interactions with HIV, neglecting coinfections with other STIs. This systematic review and meta-analysis aims to understand the role Schistosoma infections play in STIs within schistosomiasis-endemic populations.

Methods

The study is a systematic review and meta-analysis investigating the link between Schistosoma infections and STIs in endemic regions. It uses PRISMA guidelines, electronic databases, and Google Scholar to assess prevalence, associations, and heterogeneity, reducing bias using a Meta-Mar statistical tool.

Results

A quantitative synthesis of 33 articles from 1975-2024 involved 22,587 participants from 13 countries, including regions in Africa, France, and China, examining coinfections of schistosomiasis and STIs, including HIV. The pooled estimates showed a significant risk association between schistosomiasis and STIs [RR (95% CI) = 1.18, (1.13-1.24); z/t = 7.55, p<0.0001] using a fixed effect model. Cochran's Q test (Tau2 = 0.5061, Chi2 = 476.65, df = 32, p<0.01) indicated significant heterogeneity. The Higgins I2 statistic of 93.0% (91.5%-94.7%), H = 3.86 (3.43-4.33), highlighted substantial variance between studies. Subgroup analysis showed West Africa [Weight IV = 1.7%, RR (95% CI) = 1.78 (1.28-2.47), I2 = 59%], East Africa [Weight IV = 10.5%, RR (95% CI) = 0.99 (0.86-1.13), I2 = 54%], and Southern Africa [Weight IV = 82.0%, RR (95% CI) = 1.16 (1.10-1.21), I2 = 97%] contributed significantly to the high heterogeneity in the pooled analysis. Females had a notably higher risk of STIs in the context of schistosomiasis (k = 17, RR: 1.30, 95% CI: 1.23-1.37, Q = 316.78, I2 = 94.9%), compared to males (k = 6, RR: 0.94, 95% CI: 0.77-1.15, Q = 53.44, I2 = 90.6%) and the combined group of females and males (k = 9, RR: 0.95, 95% CI: 0.88-1.02, Q = 16.38, I2 = 50.2%).

Conclusion

The study found a high risk of coinfections between schistosomiasis and STIs, particularly in West and Southern Africa, confirming female genital schistosomiasis as a major risk for STIs.

A comprehensive exploration of schistosomiasis: Global impact, molecular characterization, drug discovery, artificial intelligence and future prospects

Schistosomiasis, one of the neglected tropical diseases which affects both humans and animals, is caused by trematode worms of the genus Schistosoma. The disease is caused by several species of Schistosoma which affect several organs such as urethra, liver, bladder, intestines, skin and bile ducts. The life cycle of the disease involves an intermediate host (snail) and a mammalian host. It affects people who are in close proximity to water bodies where the intermediate host is abundant. Common clinical manifestations of the disease at various stages include fever, chills, headache, cough, dysuria, hyperplasia and hydronephrosis. To date, most of the control strategies are dependent on effective diagnosis, chemotherapy and public health education on the biology of the vectors and parasites. Microscopy (Kato-Katz) is considered the golden standard for the detection of the parasite, while praziquantel is the drug of choice for the mass treatment of the disease since no vaccines have yet been developed. Most of the previous reviews on schistosomiasis have concentrated on epidemiology, life cycle, diagnosis, control and treatment. Thus, a comprehensive review that is in tune with modern developments is needed. Here, we extend this domain to cover historical perspectives, global impact, symptoms and detection, biochemical and molecular characterization, gene therapy, current drugs and vaccine status. We also discuss the prospects of using plants as potential and alternative sources of novel anti-schistosomal agents. Furthermore, we highlight advanced molecular techniques, imaging and artificial intelligence that may be useful in the future detection and treatment of the disease. Overall, the proper detection of schistosomiasis using state-of-the-art tools and techniques, as well as development of vaccines or new anti-schistosomal drugs may aid in the elimination of the disease.

Praziquantel-related visual disorders among recipients in mass drug administration campaigns in schistosomiasis endemic settings: Systematic review and meta-analysis protocol

BACKGROUND

Hundreds of millions of doses of Praziquantel (PZQ) have been administered to persons with and without schistosomiasis living in schistosomiasis endemic settings, through the mass drug administration (MDA) strategy which started in the early 2000s. A recent publication suggested high risk of PZQ-related visual disorders, raising public health concerns. We aim to systematically synthesize evidence on the magnitude of PZQ-related visual disorders.

METHODS

We will search PubMed, Google Scholar, CINAHL, SCOPUS, CENTRAL and LILACS from 1977 (when the first human clinical trials on PZQ started) to 31st May 2024, with no language restrictions. The key search terms will include "Praziquantel", "PZQ", "visual disorder", "adverse events", "side effects", "blurry vision" and "visual impairment" together with alternative terms and synonyms. All the countries endemic for schistosomiasis will be included as search terms. We will also search HINARI, Africa Journals Online, Thesis Databases and Preprint Repositories. Where necessary, we will contact expert researchers working in the field of schistosomiasis, UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR), pharmaceutical industries, country-specific Food and Drug Authorities (FDAs) and the European Medicines Agency databases. We will search Conference Proceedings and reference lists of relevant studies for additional studies. At least two authors will independently select studies, extract data and assess risk of bias in the included studies. Any disagreements or discrepancies will be resolved through discussion between the reviewers. Heterogeneity will be explored graphically, and statistically using the I2-statistic. We will conduct random-effects meta-analysis when heterogeneity is appreciable, and express dichotomous outcomes (visual adverse events including excessive lacrimation, blurry vision and visual impairments) as risk ratio (RR) or Odds Ratio (OR) with their 95% confidence interval (CI). We will perform subgroup analysis to assess the impact of heterogeneity, and sensitivity analyses to test the robustness of the effect estimates. The overall level of evidence will be assessed using GRADE.

EXPECTED OUTCOMES

The present review expects to identify and categorize visual disorders occurring after administration of PZQ, alone or in combination with other drugs. By synthesizing the data from multiple studies, the review aims to present a quantitative assessment of the risk or odds of experiencing a visual disorder in different populations after ingesting PZQ. The review will also generate insights into whether PZQ in combination with other drugs are associated with increased odds of visual disorders and whether the occurrence of visual disorders correlates with dosage or treatment duration. Policymakers, public health experts and stakeholders could rely on the review findings to deliver context-sensitive preventive chemotherapy programs by adjusting drug combinations or dosing schedules to reduce risk of visual adverse effects in populations treated with PZQ. The review aims to identify gaps in the current evidence regarding visual disorders following PZQ administration in schistosomiasis endemic settings which can serve as the basis for future research on important but unanswered questions.

DISSEMINATION AND PROTOCOL REGISTRATION

The findings of this study will be disseminated through stakeholder forums, conferences, and peer-review publications. The review protocol has been registered in the International Prospective Register for Systematic Reviews (PROSPERO)- CRD42023417963.

Insights into the epidemiology, pathogenesis, and differential diagnosis of schistosomiasis

Schistosomiasis is a neglected tropical disease that is prevalent in low- and middle-income countries. There are five human pathogenic species, of which Schistosoma haematobium, Schistosoma mansoni and Schistosoma japonicum are the most prevalent worldwide and cause the greatest burden of disease in terms of mortality and morbidity. In addition, hybrid schistosomes have been identified through molecular analysis. Human infection occurs when cercariae, the larval form of the parasite, penetrate the skin of people while bathing in contaminated waters such as lakes and rivers. Schistosomiasis can cause both urogenital and intestinal symptoms. Urogenital symptoms include haematuria, bladder fibrosis, kidney damage, and an increased risk of bladder cancer. Intestinal symptoms may include abdominal pain, sometimes accompanied by diarrhoea and blood in the stool. Schistosomiasis affects more than 250 million people and causes approximately 70 million Disability-Adjusted Life Years (DALYs), mainly in Africa, South America, and Asia. To control infection, it is essential to establish sensitive and specific diagnostic tests for epidemiological surveillance and morbidity reduction. This review provides an overview of schistosomiasis, with a focus on available diagnostic tools for Schistosoma spp. Current molecular detection methods and progress in the development of new diagnostics for schistosomiasis infection are also discussed.

Strategies and achievements in controlling and eliminating schistosomiasis from Egypt

Schistosomiasis is an old parasitic disease in Egypt primarily caused by Schistosoma mansoni, transmitted through infected water canals, and disproportionately affects rural areas. Despite substantial reductions in the disease prevalence over the years, it still affects more than 5% of the population in some governorates, highlighting the need for sustained control efforts. Among the recent control measures: (a) mass drug administration with large-scale, biannual administration of praziquantel, which remains the cornerstone of the control program targeting the interruption of vector transmission cycles. (b) Improving disease diagnostics, including point-of-care tests, which facilitate early detection and case management, particularly in remote areas. (c) Snail control using targeted mollusciciding aims to reduce parasite transmission by controlling intermediate snail hosts. And (d) behavioral change communication focusing on raising awareness regarding hygiene practices and safe water access.

Even if control attempts have shown positive results, several challenges still exist, including (a) drug resistance, especially to praziquantel, the most commonly used drug, which calls for ongoing observation and monitoring. (b) Sustainability of funding to avoid program disruptions and setbacks. And (c) social and environmental factors like poverty, poor sanitation, and access to clean water. The transition from disease control to elimination requires meticulous planning and vigilance. Robust surveillance systems, enhanced case management, and continued community engagement are vital for such elimination. Strengthening research on drug resistance, snail control methods, and innovative diagnostics would further support elimination efforts. This report aims to address the most recent data regarding the prevalence and control measures for schistosomiasis in Egypt and provide the information required to lead the transition from disease control to elimination.

Current advances in serological and molecular diagnosis of Schistosoma mekongi infection

Schistosomiasis, a neglected tropical disease, caused by blood flukes belonging to the genus Schistosoma; it persists as a public health problem in selected regions throughout Africa, South America, and Asia. Schistosoma mekongi, a zoonotic schistosome species endemic to the Mekong River in Laos and Cambodia, is one of the significant causes of human schistosomiasis along with S. japonicum, S. mansoni, S. haematobium and S. intercalatum. Since its discovery, S. mekongi infection has been highly prevalent in communities along the Mekong River. Although surveillance and control measures have shown success in recent years, more robust diagnostic tools are still needed to establish more efficient control and prevention strategies to achieve and sustain an elimination status. Diagnosis of S. mekongi infection still relies on copro-parasitological techniques, commonly made by Kato-Katz stool examination. Serological techniques such as enzyme-linked immunosorbent assay (ELISA) may also be applicable but in a limited setting. Targeted molecular and serological tools specific to the species, on the other hand, have been limited. This is due, in part, to the limited research and studies on the molecular biology of S. mekongi since genome information of this species has not yet been released. In this review, current advances, and gaps and limitations in the molecular and immunological diagnosis of S. mekongi are discussed.

High level of C3 is associated with Th2 immune response and liver fibrosis in patients with schistosomiasis

Long-term infection of schistosomiasis will seriously affect the liver health of patients. The serum of 334 chronic Schistosoma japonicum patients and 149 healthy volunteers was collected. Compared with heathy people, the level of C4 (complement 4) was increased, and the level of C3 (complement 3) was in an obvious skewed distribution. ELISA was performed to detect the serum cytokines, the results showed that the levels of IFN-γ (interferon-γ), IL (interleukin)-2 and TNF-α (tumour necrosis factor-α) were reduced, while the levels of Th2 cytokines (IL-4, IL-6 and IL-10) were increased. In the serum of patients with high C3, the secretion of HA (hyaluronic acid), LN (laminin), IV-C (type IV collagen) and PCIII (type III procollagen) were increased, the activation of hepatic stellate cells was promoted. Exogenous human recombinant C3 made mice liver structure of the mice damaged and collagen deposition. IFN-γ and IFN-γ/IL-4 were decreased, while HA, LN, PCIII and IV-C were increased, and the expressions of α-SMA and TGF-β1 in liver tissues were up-regulated. However, the addition of IFN-γ partially reversed the effect of C3 on promoting fibrosis. High level of C3 is associated with Th2 immune response and liver fibrosis in patients with schistosomiasis.

The egg ribonuclease SjCP1412 accelerates liver fibrosis caused by Schistosoma japonicum infection involving damage-associated molecular patterns (DAMPs)

Schistosomiasis, a parasite infectious disease caused by Schistosoma japonicum, often leads to egg granuloma and fibrosis due to the inflammatory reaction triggered by egg antigens released in the host liver. This study focuses on the role of the egg antigens CP1412 protein of S. japonicum (SjCP1412) with RNase activity in promoting liver fibrosis. In this study, the recombinant egg ribonuclease SjCP1412, which had RNase activity, was successfully prepared. By analysing the serum of the population, it has been proven that the anti-SjCP1412 IgG in the serum of patients with advanced schistosomiasis was moderately correlated with liver fibrosis, and SjCP1412 may be an important antigen associated with liver fibrosis in schistosomiasis. In vitro, the rSjCP1412 protein induced the human liver cancer cell line Hep G2 and liver sinusoidal endothelial cells apoptosis and necrosis and the release of proinflammatory damage-associated molecular patterns (DAMPs). In mice infected with schistosomes, rSjCP1412 immunization or antibody neutralization of SjCP1412 activity significantly reduced cell apoptosis and necroptosis in liver tissue, thereby reducing inflammation and liver fibrosis. In summary, the SjCP1412 protein plays a crucial role in promoting liver fibrosis during schistosomiasis through mediating the liver cells apoptosis and necroptosis to release DAMPs inducing an inflammatory reaction. Blocking SjCP1412 activity could inhibit its proapoptotic and necrotic effects and alleviate hepatic fibrosis. These findings suggest that SjCP1412 may be served as a promising drug target for managing liver fibrosis in schistosomiasis japonica.

Transmission-Blocking Vaccines against Schistosomiasis Japonica

Control of schistosomiasis japonica, endemic in Asia, including the Philippines, China, and Indonesia, is extremely challenging. Schistosoma japonicum is a highly pathogenic helminth parasite, with disease arising predominantly from an immune reaction to entrapped parasite eggs in tissues. Females of this species can generate 1000-2200 eggs per day, which is about 3- to 15-fold greater than the egg output of other schistosome species. Bovines (water buffalo and cattle) are the predominant definitive hosts and are estimated to generate up to 90% of parasite eggs released into the environment in rural endemic areas where these hosts and humans are present. Here, we highlight the necessity of developing veterinary transmission-blocking vaccines for bovines to better control the disease and review potential vaccine candidates. We also point out that the approach to producing efficacious transmission-blocking animal-based vaccines before moving on to human vaccines is crucial. This will result in effective and feasible public health outcomes in agreement with the One Health concept to achieve optimum health for people, animals, and the environment. Indeed, incorporating a veterinary-based transmission vaccine, coupled with interventions such as human mass drug administration, improved sanitation and hygiene, health education, and snail control, would be invaluable to eliminating zoonotic schistosomiasis.

Comprehensive analysis of miRNA profiling in Schistosoma mekongi across life cycle stages

Schistosoma mekongi, a significant schistosome parasite, has various life stages, including egg, cercaria, female, and male, that play crucial roles in the complex life cycle. This study aimed to explore the microRNA (miRNA) profiles across these developmental stages to understand their potential functions and evolutionary significance, which have not been studied. Pre-processed sequencing reads of small RNA (sRNA) were obtained, and annotations were performed against the S. japonicum reference miRNA database. Results indicated marked variations in miRNA profiles across different life stages, with notable similarities observed between female and male S. mekongi. Principal Coordinate Analysis (PCoA) and unsupervised clustering revealed distinct miRNA signatures for each stage. Gene ontology (GO) analysis unveiled the potential roles of these miRNAs in various biological processes. The differential expression of specific miRNAs was prominent across stages, suggesting their involvement in crucial developmental processes. Furthermore, orthologous miRNA analysis against various worm species revealed distinct presence-absence patterns, providing insights into the evolutionary relationships of these miRNAs. In conclusion, this comprehensive investigation into the miRNA profiles of S. mekongi offers valuable insights into the functional and evolutionary aspects of miRNAs in schistosome biology.

A Mini-Review on Elisa-Based Diagnosis of Schistosomiasis

BACKGROUND

Schistosomiasis is a neglected tropical parasitic disease caused by trematode worms of the genus schistosoma, which affects approximately 240 million people worldwide. the diagnosis of the disease can be performed by parasitological, molecular, and/or immunological methods, however, the development of new diagnostic methods still essential to guide policy decisions, monitor disease trends and assess the effectiveness of interventions.

OBJECTIVE

in this sense, the current work summarizes the findings of a systematic review regarding antigens applied in the enzyme-linked immunosorbent assay test, which were patented and published over the last ten years.

METHODS

the literature search strategy used medical subject heading (mesh) terms to define as descriptors. "schistosoma mansoni" was used in arrangement with the descriptors "immunoassay", "enzyme-linked immunosorbent assay", "elisa", and "antigens", using the "and" connector. the patent search was done using keywords, including diagnosis and schistosoma or schistosomiasis or schistosome. several databases were employed for the patent search, such as intellectual property national institute; european patent office; the united states patent and trademark office; patent scope, and google patents.

RESULTS

forty-one articles were retrieved, of which only five met the eligibility criteria. seventeen patents were taken from the databases, and a brief description of the most relevant inventions is given here.

CONCLUSION

schistosomiasis is considered the most important helminthic disease in worldwide. therefore, it is important to of searching for and develops diagnostic methods based on serology to reduce morbidity and mortality caused by the disease.

The Cytokine Profile in Different Stages of Schistosomiasis Japonica

To explore and profile the level of cytokines in the sera of patients infected with Schistosoma japonicum to explore the helper T-cell response of patients either at the chronic or advanced stage of the disease. We randomly selected 58 subjects from several areas endemic for schistosomiasis japonica in China and collected serum samples to be tested for 18 different cytokines secreted by (1) Th1/Th2 cells (GM-CSF, IFN-γ, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-12p70, IL-10, IL-13, IL-18 and TNF-α) and (2) Th9/Th17/Th22/Treg cells (IL-9, IL-17A, IL-21, IL-22, IL-23 and IL-27). The Th1/Th2 cytokines in chronic patients were not significantly different from those in healthy people, while patients with advanced schistosomiasis had higher levels of IL-2, IL-23 and IL-27 and lower levels of IL-18 and IFN-γ. With respect to the Th9/Th17/Th22/Treg cell cytokines, there were higher levels of IL-23. Thus, a limited variation of the cytokine response between the three patient groups was evident, but only in those with advanced infection, while there was no difference between chronic schistosomiasis infection and healthy subjects in this respect. The cytokine expression should be followed in patients with advanced schistosomiasis who show a cytokine pattern of a weakened Th1 cell response and an increased Th17 response.

Development of CRISPR/Cas13a-based assays for the diagnosis of Schistosomiasis

BACKGROUND

Schistosomiasis is a disease that significantly impacts human health in the developing world. Effective diagnostics are urgently needed for improved control of this disease. CRISPR-based technology has rapidly accelerated the development of a revolutionary and powerful diagnostics platform, resulting in the advancement of a class of ultrasensitive, specific, cost-effective and portable diagnostics, typified by applications in COVID-19/cancer diagnosis.

METHODS

We developed CRISPR-based diagnostic platform SHERLOCK (Specific High-sensitivity Enzymatic Reporter unLOCKing) for the detection of Schistosoma japonicum and S. mansoni by combining recombinase polymerase amplification (RPA) with CRISPR-Cas13a detection, measured via fluorescent or colorimetric readouts. We evaluated SHERLOCK assays by using 150 faecal/serum samples collected from Schistosoma-infected ARC Swiss mice (female), and 189 human faecal/serum samples obtained from a S. japonicum-endemic area in the Philippines and a S. mansoni-endemic area in Uganda.

FINDINGS

The S. japonicum SHERLOCK assay achieved 93-100% concordance with gold-standard qPCR detection across all the samples. The S. mansoni SHERLOCK assay demonstrated higher sensitivity than qPCR and was able to detect infection in mouse serum as early as 3 weeks post-infection. In human samples, S. mansoni SHERLOCK had 100% sensitivity when compared to qPCR of faecal and serum samples.

INTERPRETATION

These schistosomiasis diagnostic assays demonstrate the potential of SHERLOCK/CRISPR-based diagnostics to provide highly accurate and field-friendly point-of-care tests that could provide the next generation of diagnostic and surveillance tools for parasitic neglected tropical diseases.

FUNDING

Australian Infectious Diseases Research Centre seed grant (2022) and National Health and Medical Research Council (NHMRC) of Australia (APP1194462, APP2008433).

Small change, big difference: A promising praziquantel derivative designated P96 with broad-spectrum antischistosomal activity for chemotherapy of schistosomiasis japonica

BACKGROUND

Praziquantel (PZQ) has been the first line antischistosomal drug for all species of Schistosoma, and the only available drug for schistosomiasis japonica, without any alternative drugs since the 1980s. However, PZQ cannot prevent reinfection, and cannot cure schistosomiasis thoroughly because of its poor activity against juvenile schistosomes. In addition, reliance on a single drug is extremely dangerous, the development and spread of resistance to PZQ is becoming a great concern. Therefore, development of novel drug candidates for treatment and control of schistosomiasis is urgently needed.

METHODOLOGYS/PRINCIPAL FINDINGS

One of the PZQ derivative christened P96 with the substitution of cyclohexyl by cyclopentyl was synthesized by School of Pharmaceutical Sciences of Shandong University. We investigated the in vitro and in vivo activities of P96 against different developmental stages of S. japonicum. Parasitological studies and scanning electron microscopy were used to study the primary action characteristics of P96 in vitro. Both mouse and rabbit models were employed to evaluate schistosomicidal efficacy of P96 in vivo. Besides calculation of worm reduction rate and egg reduction rate, quantitative real-time PCR was used to evaluate the in vivo antischistosomal activity of P96 at molecular level. In vitro, after 24h exposure, P96 demonstrated the highest activities against both juvenile and adult worm of S. japonicum in comparison to PZQ. The antischistosomal efficacy was concentration-dependent, with P96 at 50μM demonstrating the most evident schistosomicidal effect. Scanning electron microscopy demonstrated that P96 caused more severe damages to schistosomula and adult worm tegument compared to PZQ. In vivo, our results showed that P96 was effective against S. japonicum at all developmental stages. Notably, its efficacy against young stage worms was significantly improved compared to PZQ. Moreover, P96 retained the high activity comparable to PZQ against the adult worm of S. japonicum.

CONCLUSIONS

P96 is a promising drug candidate for chemotherapy of schistosomiasis japonica, which has broad spectrum of action against various developmental stage, potentially addressing the deficiency of PZQ. It might be promoted as a drug candidate for use either alone or in combination with PZQ for the treatment of schistosomiasis.

Trend of Human Schistosomiasis Japonica Prevalence in China from 1990 to 2019

Schistosomiasis (Schistosomiasis japonica) remains an important public health problem in China, and the Chinese government has set an ambitious goal of eliminating schistosomiasis by 2030. Based on the observational study of the Global Burden of Disease Study database in 2019 (GBD2019) and the World Bank database, this study aimed to analyze the prevalence trend of schistosomiasis in China from 1990 to 2019 by using the joinpoint regression model, and the relationship between economic and social development and schistosomiasis prevalence. The data of age-standardized infection rates (ASRs) from the Global Burden of Disease Study Global Health Data Exchange were collected, and Gross national product per capita (GDP) and people using safely managed sanitation services ((PPMS) % of population) were extracted from the World Bank database. Trends of ASR were analyzed using joinpoint regression analysis, the association of ASR with GDP, and PPMS using the Pearson correlation analysis. The results reveal that, from 1990 to 2019, the overall trend of ASR from schistosomiasis showed a decrease for both sexes, the decreases in men were relatively smaller compared with women. A larger decrease has been observed in the age groups from 15 to 49 years compared with other age groups. The ASR of schistosomiasis had a significant negative correlation with GDP and PPMS. This observational study identified decreasing prevalence rate of schistosomiasis in China since 1990. Continuous investment, optimization of control strategy, and economic development will help to achieve the goal of schistosomiasis elimination.

Evaluation of IL-35, as a Possible Biomarker for Follow-Up after Therapy, in Chronic Human Schistosoma Infection

The host response to helminth infections is characterized by systemic and tissue-related immune responses that play a crucial role in pathological diseases. Recently, experimental studies have highlighted the role of regulatory T (Tregs) and B (Bregs) cells with secreted cytokines as important markers in anti-schistosomiasis immunity. We investigated the serical levels of five cytokines (TNFα, IFN-γ, IL-4, IL-10 and IL-35) in pre- and post-treatment samples from chronic Schistosoma infected patients to identify potential serological markers during follow-up therapy. Interestingly, we highlighted an increased serum level of IL-35 in the pre-therapy samples (median 439 pg/mL for Schistosoma haematobium and 100.5 pg/mL for Schistsoma mansoni infected patients) compared to a control group (median 62 pg/mL and 58 pg/mL, respectively, p ≤ 0.05), and a significantly lower concentration in post-therapy samples (181 pg/mL for S. haematobium and 49.5 pg/mL for S. mansoni infected patients, p ≤ 0.05). The present study suggests the possible role of IL-35 as a novel serological biomarker in the evaluation of Schistosoma therapy follow-up.

Anti-schistosomal immunity to core xylose/fucose in N-glycans

Schistosomiasis is a globally prevalent, debilitating disease that is poorly controlled by chemotherapy and for which no vaccine exists. While partial resistance in people may develop over time with repeated infections and treatments, some animals, including the brown rat (Rattus norvegicus), are only semi-permissive and have natural protection. To understand the basis of this protection, we explored the nature of the immune response in the brown rat to infection by Schistosoma mansoni. Infection leads to production of IgG to Infection leads to production of IgG to parasite glycoproteins parasite glycoproteins with complex-type N-glycans that contain a non-mammalian-type modification by core α2-Xylose and core α3-Fucose (core Xyl/Fuc). These epitopes are expressed on the surfaces of schistosomula and adult worms. Importantly, IgG to these epitopes can kill schistosomula by a complement-dependent process in vitro. Additionally, sera from both infected rhesus monkey and infected brown rat were capable of killing schistosomula in a manner inhibited by glycopeptides containing core Xyl/Fuc. These results demonstrate that protective antibodies to schistosome infections in brown rats and rhesus monkeys include IgG responses to the core Xyl/Fuc epitopes in surface-expressed N-glycans, and raise the potential of novel glyco-based vaccines that might be developed to combat this disease.

A Critical Review on Human Malaria and Schistosomiasis Vaccines: Current State, Recent Advancements, and Developments

Malaria and schistosomiasis are two major parasitic diseases that remain leading causes of morbidity and mortality worldwide. Co-infections of these two parasites are common in the tropics, where both diseases are endemic. The clinical consequences of schistosomiasis and malaria are determined by a variety of host, parasitic, and environmental variables. Chronic schistosomiasis causes malnutrition and cognitive impairments in children, while malaria can cause fatal acute infections. There are effective drugs available to treat malaria and schistosomiasis. However, the occurrence of allelic polymorphisms and the rapid selection of parasites with genetic mutations can confer reduced susceptibility and lead to the emergence of drug resistance. Moreover, the successful elimination and complete management of these parasites are difficult due to the lack of effective vaccines against Plasmodium and Schistosoma infections. Therefore, it is important to highlight all current vaccine candidates undergoing clinical trials, such as pre-erythrocytic and erythrocytic stage malaria, as well as a next-generation RTS,S-like vaccine, the R21/Matrix-M vaccine, that conferred 77% protection against clinical malaria in a Phase 2b trial. Moreover, this review also discusses the progress and development of schistosomiasis vaccines. Furthermore, significant information is provided through this review on the effectiveness and progress of schistosomiasis vaccines currently under clinical trials, such as Sh28GST, Sm-14, and Sm-p80. Overall, this review provides insights into recent progress in malarial and schistosomiasis vaccines and their developmental approaches.

The Current Distribution of Oncomelania hupensis Snails in the People's Republic of China Based on a Nationwide Survey

Schistosomiasis is a helminth infection caused by the genus Schistosoma, which is still a threat in tropical and sub-tropical areas. In the China, schistosomiasis caused by Schistosoma japonicum is mainly endemic to the Yangtze River valley. The amphibious snail Oncomelania hupensis (O. hupensis) is the unique intermediate host of S. japonicum; hence, snail control is a crucial approach in the process of schistosomiasis transmission control and elimination. In 2016, a nationwide snail survey was conducted involving all snail habitats recorded since 1950 in all endemic counties of 12 provinces. A total of 53,254 existing snail habitats (ESHs) were identified, presenting three clusters in Sichuan Basin, Dongting Lake, and Poyang Lake. The overall habitat area was 5.24 billion m2, of which 3.58 billion m2 were inhabited by O. hupensis. The area inhabited by snails (AIS) in Dongting and Poyang Lakes accounted for 76.53% of the population in the country. Three typical landscape types (marshland and lakes, mountains and hills, and plain water networks) existed in endemic areas, and marshland and lakes had a predominant share (3.38 billion m2) of the AIS. Among the 12 endemic provinces, Hunan had a share of nearly 50% of AIS, whereas Guangdong had no ESH. Ditches, dryland, paddy fields, marshland, and ponds are common habitat types of the ESH. Although the AIS of the marshland type accounted for 87.22% of the population in the whole country, ditches were the most common type (35,025 or 65.77%) of habitat. Six categories of vegetation for ESHs were identified. A total of 39,139 habitats were covered with weeds, accounting for 55.26% of the coverage of the area. Multiple vegetation types of snail habitats appeared in the 11 provinces, but one or two of these were mainly dominant. Systematic sampling showed that the presence of living snails was 17.88% among the 13.5 million sampling frames. The occurrence varied significantly by landscape, environment, and vegetation type. The median density of living snails in habitats was 0.50 per frame (0.33 m × 0.33 m), and the highest density was 40.01 per frame. Furthermore, two main clusters with high snail densities and spatial correlations indicated by hotspot analysis were identified: one in Hunan and Hubei, the other in Sichuan. This national survey is the first full-scale census on the distribution of O. hupensis, which is significant, as transmission interruption and elimination are truly becoming the immediate goal of schistosomiasis control in China. The study discerns the detailed geographic distribution of O. hupensis with the hotspots of snail density in China. It is beneficial to understand the status of the snail population in order to finally formulate further national control planning.

Contribution of the TIM-3/Gal-9 immune checkpoint to tropical parasitic diseases

Neglected tropical parasitic diseases (NTD) are prevalent in many countries and cost-effective treatments remain urgently needed. Novel approaches have been proposed to address these diseases through an action on immune co-inhibitory checkpoints which are exploited by parasites to evade the immune system. Among these checkpoints, TIM-3 has been shown to play a key role in antiparasitic immunity via a repression and functional attenuation of CD4⁺ and/or CD8⁺ T-cells. The present review discusses the role of the TIM-3/galectin-9 checkpoint in seven major NTD: Chagas disease, leishmaniasis and malaria (3 trypanosomatid infections), schistosomiasis, toxoplasmosis, echinococcosis and filariasis (4 helminth infections). In each case, the role of the checkpoint has been analyzed and the use of anti-TIM-3 antibodies evaluated as a potential therapeutic approach. In general, the parasitic infection is coupled with an upregulation of TIM-3 expressed on T cells, but not necessarily with an exhaustion of those T cells. In several cases, the use of anti-TIM-3 antibodies represent a possible strategy to reinforce the clearance and to reduce the parasite load. Promising data have been reported in cases of leishmaniasis, malaria and schistosomiasis, whereas a similar approach proved much less efficient (if not deleterious) in cases of echinococcosis and the Chagas disease. Nevertheless, the TIM-3 checkpoint warrants further consideration as a potential immune target to combat these pathologies, using antibodies or drugs capable of reducing directly or indirectly the expression and function of the checkpoint, to restore an immune control.

Assessment of the accuracy of 11 different diagnostic tests for the detection of Schistosomiasis mansoni in individuals from a Brazilian area of low endemicity using latent class analysis

Background

Schistosomiasis is a parasitic disease associated with poverty. It is estimated that 7.1 million people are infected with Schistosoma mansoni in Latin America, with 95% of them living in Brazil. Accurate diagnosis and timely treatment are important measures to control and eliminate schistosomiasis, but diagnostic improvements are needed to detect infections, especially in areas of low endemicity.

Methodology

This research aimed to evaluate the performance of 11 diagnostic tests using latent class analysis (LCA). A cross-sectional survey was undertaken in a low endemicity area of the municipality of Malacacheta, Minas Gerais, Brazil. Feces, urine, and blood samples were collected from 400 residents older than 6 years of age, who had not been treated with praziquantel in the 12 months previous to the collection of their samples. The collected samples were examined using parasitological (Helm Test® kit Kato-Katz), nucleic acid amplification tests -NAATs (PCR, qPCR and LAMP on urine; PCR-ELISA, qPCR and LAMP on stool), and immunological (POC-CCA, the commercial anti-Schistosoma mansoni IgG ELISA kit from Euroimmun, and two in-house ELISA assays using either the recombinant antigen PPE or the synthetic peptide Smp150390.1) tests.

Results

The positivity rate of the 11 tests evaluated ranged from 5% (qPCR on urine) to 40.8% (commercial ELISA kit). The estimated prevalence of schistosomiasis was 12% (95% CI: 9-15%) according to the LCA. Among all tests assessed, the commercial ELISA kit had the highest estimated sensitivity (100%), while the Kato-Katz had the highest estimated specificity (99%). Based on the accuracy measures observed, we proposed three 2-step diagnostic approaches for the active search of infected people in endemic settings. The approaches proposed consist of combinations of commercial ELISA kit and NAATs tests performed on stool. All the approaches had higher sensitivity and specificity than the mean values observed for the 11 tests (70.4 and 89.5%, respectively).

Conclusion

We showed that it is possible to achieve high specificity and sensitivity rates with lower costs by combining serological and NAATs tests, which would assist in the decision-making process for appropriate allocation of public funding aiming to achieve the WHO target of eliminating schistosomiasis as a public health problem by 2030.

Development of real-time and lateral flow recombinase polymerase amplification assays for rapid detection of Schistosoma mansoni

Background

Accurate diagnosis followed by timely treatment is an effective strategy for the prevention of complications together with reducing schistosomiasis transmission. Recombinase Polymerase Amplification (RPA) is a simple, rapid, sensitive, and specific isothermal method with low resource needs. This research aimed at the development and optimisation of a real-time (RT) and a lateral flow (LF) RPA assay for the detection of Schistosoma mansoni.

Methodology

Recombinase Polymerase Amplification reactions were performed at full- (as recommended) and half-volumes (to reduce costs), with RT or LF detection systems targeting the S. mansoni mitochondrial minisatellite region. The specificity was assessed using gDNA from other Schistosoma species, helminths co-endemic with S. mansoni, human stool, and urine, and Biomphalaria snail hosts. The analytical sensitivity was evaluated using serial dilutions of gDNA, synthetic copies of the target, and single eggs. The ability of both assays to detect the S. mansoni DNA in human urine and stool samples was also tested. The long-term stability of the RT-RPA reagents was evaluated by storing the reaction components in different temperature conditions for up to 3  weeks.

Results

The RT- and the LF-RPA (SmMIT- and SmMIT-LF-RPA, respectively) presented similar results when used full- and half-volumes, thus the latter was followed in all experiments. The SmMIT-RPA was 100% specific to S. mansoni, able to detect a single egg, with a limit of detection (LOD) of down to 1  fg of gDNA and one synthetic copy of the target. The assay was able to detect S. mansoni DNA from stool containing 1 egg/g and in spiked urine at a concentration of 10  fg/μl. SmMIT-RPA reagents were stable for up to 3  weeks when kept at 19°C, and 2  weeks when stored at 27°C. The SmMIT-LF-RPA cross-reacted with Clinostomidae, presented the LOD of 10  fg and one synthetic copy of the target, being able to detect a single egg and 1 egg/g in a stool sample. The LOD in spiked urine samples was 10  pg/μl.

Conclusion

The half-volume SmMIT-RPA is a promising method to be used in the field. It is specific, sensitive, robust, and tolerant to inhibitors, with a long-term stability of the reaction components and the real-time visualisation of results.

The Role of Praziquantel in the Prevention and Treatment of Fibrosis Associated with Schistosomiasis: A Review

Schistosomiasis remains a major global public health concern. Currently, the control of this neglected tropical disease still depends on chemotherapy to reduce the prevalence and intensity of the parasite infection. It has been widely accepted that praziquantel is highly effective against all species of Schistosoma, and this agent is virtually the only drug of choice for the treatment of human schistosomiasis. Mass drug administration (MDA) with praziquantel has been shown to be effective in greatly reducing the prevalence and morbidity due to schistosomiasis worldwide. In addition to antischistosomal activity, a large number of experiential and clinical evidence has demonstrated the action of praziquantel against fibrosis caused by S. mansoni and S. japonicum infections through decreasing the expression of fibrotic biomarkers such as α-smooth muscle actin (α-SMA), collagen, matrix metalloproteinase (MMP), and tissue inhibitor of metalloproteinase (TIMP), and inhibiting the expression of proinflammatory cytokines such as interleukin (IL)-6, tumor necrosis factor (TNF)-α, and transforming growth factor (TGF)-β, as well as chemokines, and similar antifibrotic activity was observed in mouse models of fibrosis induced by carbon tetrachloride (CCl4) and concanavalin A (Con-A). In this review, we discuss the role of praziquantel in the prevention and treatment of fibrosis associated with schistosomiasis and the possible mechanisms. We call for randomized, controlled clinical trials to evaluate the efficacy and safety of praziquantel in the treatment of schistosomiasis-induced hepatic fibrosis, and further studies to investigate the potential of praziquantel against fibrosis associated with alcohol consumption, viruses, and toxins seem justified.