Paediatric schistosomiasis: What we know and what we need to know

Pediatric urogenital schistosomiasis diagnosed in France

BACKGROUND

Schistosomiasis affects approximately 230 million people worldwide. There is an increased incidence of schistosomiasis cases in France acquired from outside the country. This increases the risk of schistosomiasis outbreaks as observed in Corsica. Clinicians from non-endemic regions are not accustomed to diagnosing and managing this pathology. The objective of this study is to provide a better description of the clinical and paraclinical characteristics and disease evolution of affected children.

METHODS

Through the French Pediatric Nephrology Society and the Pediatric Infectious Pathology Group, we contacted all French pediatric centers that may have treated children with urinary schistosomiasis between 2013 and 2019. Age, sex, comorbidities, and clinical, biological, and radiological data (at discovery and follow-up) were collected retrospectively.

RESULTS

A total of 122 patients from 10 different centers were included. The median age was 14 years and the sex ratio M/F was 4:1. Hematuria was present in 82% of the patients while urinary tract abnormality was found in 36% of them. Fourteen patients (11%) displayed complicated forms of urinary schistosomiasis including 10 patients with chronic kidney disease. A total of 110 patients received treatment with praziquantel, which was well-tolerated and led to clinical resolution of symptoms in 98% of cases.

CONCLUSION

Patients with schistosomiasis present frequent kidney, urinary, or genital involvement. Systematic screening of patients returning from endemic areas is therefore recommended, especially since treatment with antiparasitic drugs is effective and well-tolerated. Enhancing medical knowledge of this pathology among all practitioners is essential to improve care and outcomes.

Threshold dynamics of a reaction-advection-diffusion schistosomiasis epidemic model with seasonality and spatial heterogeneity

Most water-borne disease models ignore the advection of water flows in order to simplify the mathematical analysis and numerical computation. However, advection can play an important role in determining the disease transmission dynamics. In this paper, we investigate the long-term dynamics of a periodic reaction-advection-diffusion schistosomiasis model and explore the joint impact of advection, seasonality and spatial heterogeneity on the transmission of the disease. We derive the basic reproduction number R 0 and show that the disease-free periodic solution is globally attractive whenR 0 < 1 whereas there is a positive endemic periodic solution and the system is uniformly persistent in a special case whenR 0 > 1 . Moreover, we find that R 0 is a decreasing function of the advection coefficients which offers insights into why schistosomiasis is more serious in regions with slow water flows.

Where will pediatric praziquantel be needed in Tanzania? Geographical variation in prevalence, and risk factors of Schistosoma mansoni in pre-school aged children in southern and north-western Tanzania

Background

Pediatric schistosomiasis has been recognized as a public health concern in schistosomiasis endemic areas of sub-Saharan Africa, including Tanzania. However, there is limited epidemiological information relating to pediatric schistosomiasis in Tanzania. Therefore, this current focused on assessing the geographical prevalence of S. mansoni infection and its associated risk factors in pre-school children (PreSAC) in southern and north-western Tanzania.

Methods

A total of 1585 PreSAC aged 1-6 years were enrolled in a cross-sectional study. A single urine and stool sample were obtained from each child and processed using point-of-care circulating cathodic (POC-CCA) antigen and Kato Katz (K-K) technique. The overall prevalence of S. mansoni infection based on K-K technique and POC-CCA test were 18.6% (95%CI:16.7-20.6) and 28.3% (95%CI:26.1-30.6), respectively. The overall geometrical mean eggs per gram of faeces was 110.38epg (95% CI:97.3-125.3). The age group 4-6 years had the highest prevalence (P < 0.01) of S. mansoni in both diagnostic tests and infection intensity (t = -2.8398, P < 0.005) using K-K technique. On multivariable analysis, only Ukerewe district was associated with S. mansoni infection based on K-K technique (aOR = 2.8 (95%CI:2.1-3.9), P < 0.001). Based on POC-CCA test, age group (4-6 years), aOR = 1.7, 95%CI:1.3-2.2, P < 0.001), Nyasa (aOR = 6.2, 95%CI:3.0-12.5, P < 0.001), Geita (aOR = 4.2, 95%CI:2.1-8.2, P < 0.001) and Ukerewe (aOR = 28.9, 95%CI:15.0-55.8, P < 0.001) districts remained independently associated with S. mansoni infection.

Conclusion

Schistosoma mansoni is a public health concern among PreSAC in the study districts and its prevalence varies from one geographical setting to another. These findings strongly support the need to include pre-school aged in preventive chemotherapy.

Schistosome Transgenesis: The Long Road to Success

As research on parasitic helminths has entered the post-genomic era, research efforts have turned to deciphering the function of genes in the public databases of genome sequences. It is hoped that, by understanding the role of parasite genes in maintaining their parasitic lifestyle, critical insights can be gained to develop new intervention and control strategies. Methods to manipulate and transform parasitic worms are now developed to a point where it has become possible to gain a comprehensive understanding of the molecular mechanisms underlying host-parasite interplay, and here, we summarise and discuss the advances that have been made in schistosome transgenesis over the past 25 years. The ability to genetically manipulate schistosomes holds promise in finding new ways to control schistosomiasis, which ultimately may lead to the eradication of this debilitating disease.

Diagnosis of Human Trematode Infections

Digenetic trematodes form a major group of human parasites, affecting a large number of humans, especially in endemic foci. Over 100 species have been reported infecting humans, including blood, lung, liver and intestinal parasites. Traditionally, trematode infections have been diagnosed by parasitological methods based on the detection and the identification of eggs in different clinical samples. However, this is complicated due to the morphological similarity between eggs of different trematode species and other factors such as lack of sensitivity or ectopic locations of the parasites. Moreover, the problem is currently aggravated by migratory flows, international travel, international trade of foods and changes in alimentary habits. Although efforts have been made for the development of immunological and molecular techniques, the detection of eggs through parasitological techniques remains as the gold standard for the diagnosis of trematodiases. In the present chapter, we review the current status of knowledge on diagnostic techniques used when examining feces, urine, and sputum and also analyze the most relevant characteristics used to identify eggs with a quick key for the identification of eggs.

Schistosoma japonicum Associated Colorectal Cancer and Its Management

BACKGROUND

An association between Schistosoma japonicum and colorectal cancer in humans has been known since a long time; however, this association remains understudied and lacks comprehensive experimentation support.

OBJECTIVE

Various epidemiological and pathological studies have established the role of chronic inflammation as a major factor behind the induction of colorectal cancer. The aim of this review is to present the current knowledge on the association of Schistosoma japonicum with colorectal cancer.

RESULT

Mechanisms which lead to induction and progression of colorectal cancer are highlighted along with diagnosis and treatment for the same. Further, various methodologies, including mass drug administration, use of new drugs and vaccines, role of apoptosis, and histone-modifying enzymes, have been described which can either prevent the schistosomal infection itself or can check it from reaching an advanced stage.

CONCLUSIONS

Epidemiological, clinical, pathological and surgical studies suggest that Schistosoma japonicum is responsible for induction of colorectal cancer. However, thorough clinical studies are required to support and globally accept this notion. Further, methodologies highlighted in this work can be employed in order to take care of schistosomal infection or address the cancer induction and progression.

Assessing the knowledge, attitudes, practices, and perspectives of stakeholders of the deworming program in rural Rwanda

BACKGROUND

Worm infections are among the most prevalent neglected tropical diseases worldwide. Schistosomiasis and soil-transmitted helminths infections, most common worm infections affecting Rwandan school-aged children, are addressed by the national deworming program since 2014. To date, no published studies have assessed the knowledge, attitudes, and practices of the key implementers of the national deworming program conducted at village and school level in Rwanda. This study aimed to assess key stakeholders' knowledge, attitudes, practices, and perspectives about the decentralized national deworming program.

METHODS/PRINCIPAL FINDINGS

We carried out a quantitative, cross-sectional study with complementary in-depth interviews in two districts of Rwanda in June 2021. From the 852 surveyed community health workers and teachers, 54.1% had a knowledge score considered good (≥80%). The mean knowledge score was 78.04%. From the multivariate analysis, lack of training was shown to increase the odds of having poor knowledge (OR 0.487, 95% CI: 0.328-0.722, p <0.001). The in-depths interviews revealed poor water access and hesitance from caregivers as perceived challenges to the success of the deworming program.

CONCLUSION

Our findings demonstrate the importance of training community health workers and schoolteachers on worm infections as they are the key implementers of the deworming program. This would enhance their capacity to provide health education and sensitization on misconceptions and misinformation towards deworming. Moreover, research is needed to assess the impact of poor access to water, sanitation and hygiene facilities on the prevalence of worm infections in Rwanda.

Prevalence and Determinants of Schistosoma mansoni Infection among Pre-School Age Children in Southern Ethiopia

School-based deworming program is implemented to control and eliminate Schistosoma mansoni infection in many endemic countries, including Ethiopia. However, pre-school-age children (pre-SAC) are not targeted to receive preventive chemotherapy against S. mansoni infection, partly due to a lack of information on the disease burden. We assessed the prevalence and correlates of S. mansoni infection among pre-SAC in Southern Ethiopia. A total of 1683 pre-SAC aged 4 to 7 years were screened for S. mansoni infection. A multilevel binary logistic regression was fitted to detect the significant determinants of S. mansoni infection. Adjusted odds ratios (AORs) with a 95% confidence interval (CI) were used to identify determinants of S. mansoni infection. The overall prevalence of S. mansoni infection was 14.3% (95% CI: 12.6, 16.0%). S. mansoni infection was significantly higher among 6-year-old (AOR = 2.58, 95% CI: 1.55, 4.27) and 7-year-old children (AOR = 4.63, 95% CI: 2.82, 7.62). Accompanying others to water sources sometimes (AOR = 2.60, 95% CI: 1.12, 6.01) and all the time (AOR = 5.91, 95% CI: 2.51, 13.90), and residing in less than one kilometer from the infested water source (AOR = 3.17, 95% CI: 1.47, 6.83) increased the odds of S. mansoni infection. In conclusion, the prevalence of S. mansoni infection among pre-SAC in the study area was moderate. The study highlights the urgent need to include pre-SAC aged 4 to 7 years in annual preventive chemotherapy campaigns to reduce the risk of possible sources of infection and enhance the achievement of the elimination target.

Epidemiology of pediatric schistosomiasis in hard-to-reach areas and populations: a scoping review

BACKGROUND

Schistosomiasis affects over 250 million people worldwide. Despite children and the poor being key risk groups, limited research and control activities target pre-school aged children (PSAC) and hard-to-reach populations. As endemic countries shift the goals of their schistosomiasis programs from morbidity control to disease elimination, there is a need for inclusive planning to cover all affected age groups from all geographical areas and populations to achieve sustainable impact and health equity.

METHODS

We conducted searches in MEDLINE, Web of Science, Embase (Ovid), and LILACS per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses-Extension for Scoping Reviews (PRISMA-ScR) guidelines. Quality assessment of identified articles was done using the Joanna Briggs Institute Prevalence Critical Appraisal Tool. Relevant study data were extracted from the articles and entered into Microsoft Excel 2016 for descriptive analysis.

RESULTS

From the 17,179 screened articles, we identified 13 eligible studies on schistosomiasis in PSAC living in hard-to-reach areas and populations. All identified studies were from sub-Saharan Africa. The mean sample size of the retained studies was 572, with a balanced sex distribution among the young children sampled in each study. Ten studies investigated Schistosoma mansoni, one investigated Schistosoma haematobium, while two covered both S. mansoni and S. haematobium in the target population. The prevalence of S. mansoni among PSAC in the included studies was estimated at 12.9% in Ghana, 80.3-90.5% in Kenya, 35.0% in Madagascar, 9.6-78.0% in Senegal, 11.2-35.4% in Sierra Leone, 44.4-54.9% in Tanzania and 39.3-74.9% in Uganda. Out of the three studies that investigated S. haematobium, the presence of the infection was reported in only one study carried out in Nigeria. Schistosome infections reported in nearly all studies included in this review were of light intensity. Only one study conducted in Nigeria documented visible hematuria in 17.7% of the PSAC studied.

CONCLUSIONS

The findings document the high prevalence of schistosomiasis among PSAC in hard-to-reach populations and underscore the need to consider this population subgroup when designing the expansion of preventive chemotherapy and schistosomiasis control activities.

CRISPR-assisted test for Schistosoma haematobium

Schistosomiasis is a major neglected tropical disease targeted for elimination as a public health issue by 2030, however there is an urgent need for more sensitive and specific diagnostic tests suitable to resource-limited settings. Here we developed CATSH, a CRISPR-assisted diagnostic test for Schistosoma haematobium, utilising recombinase polymerase amplification, Cas12a-targeted cleavage and portable real-time fluorescence detection. CATSH showed high analytical sensitivity, consistent detection of a single parasitic egg and specificity for urogenital Schistosoma species. Thanks to a novel CRISPR-compatible sample preparation developed using simulated urine samples containing parasitic eggs, CATSH had a sample-to-result within 2 h. The components of CATSH can be lyophilised, reducing cold chain dependence and widening access to lower and middle-income countries. This work presents a new application of CRISPR diagnostics for highly sensitive and specific detection of parasitic pathogens in remote areas and could have a significant impact on the elimination of neglected tropical diseases.

Metabolomics for biomarker discovery in schistosomiasis: A systematic scoping review

Background

Metabolomic based approaches are essential tools in the discovery of unique biomarkers for infectious diseases via high-throughput global assessment of metabolites and metabolite pathway dysregulation. This in-turn allows the development of diagnostic tools and provision of therapeutics. In this review, we aimed to give an overview of metabolite biomarkers and metabolic pathway alterations during Schistosoma haematobium and Schistosoma mansoni infections.

Methods

We conducted the review by systematically searching electronic databases and grey literature to identify relevant metabolomics studies on schistosomiasis. Arksey and O’Malley methodology for conducting systematic scoping reviews was applied. A narrative summary of results was conducted following the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for scoping review guidelines.

Results

Twelve articles included in the review identified 127 metabolites, whose concentrations were considerably altered during S. mansoni and S. haematobium infections. The metabolites were assigned to metabolic pathways involved in energy (34.6%), gut microbial (11.0%), amino acid (25.2%), nucleic acids (6.3%), immune proteins (8.7%) hormones (2.4%) and structural proteins/lipids (11.8%). Energy related metabolic pathways were the most affected during schistosome infections with metabolites such as succinate, citrate, aconitate and fumarate of the tricarbocylic acid cycle being significantly altered in organ, serum and plasma samples. Amino acid metabolism was also impacted during schistosome infections as phenylacetylglycine, alanine, taurine, 2-oxoisocaproate and 2-oxoisovalerate emerged as potent biomarkers. Elevated structural proteins such as actin, collagen and keratin concentrations were identified as biomarkers of liver fibrosis, a common pathological feature in chronic schistosomiasis infections. Hippurate was a major metabolite biomarker in the gut microbial related pathway.

Conclusions

The analysis of the literature revealed that energy related metabolic pathways are considerably altered during S. mansoni and S. haematobium infections. Therefore, their metabolites may provide biomarkers for diagnosis and prognosis in addition to providing therapeutics for parasitic infections. This scoping review has identified a need to replicate more schistosomiasis metabolomic studies in humans to complement animal-model based studies.

Epidemiology of pediatric schistosomiasis in hard-to-reach areas and populations: A scoping review protocol

Background: Schistosomiasis is a neglected tropical disease (NTD) that affects millions of people. Children are the most vulnerable group to developing overt disease. An estimated 779 million people are at risk of schistosomiasis and 50 million preschool-age children (PSAC) need treatment. PSAC are not currently targeted by national chemotherapy campaigns due to a lack of suitable pediatric formulations of praziquantel. The Pediatric Praziquantel Consortium has developed an orally dispersible praziquantel formulation (arpraziquantel) and is facilitating its adoption for schistosomiasis control by endemic countries through the ADOPT program - an implementation research program that paves the way for the large-scale delivery of the child-friendly formulation to treat schistosomiasis in preschool-aged children in endemic countries. A key challenge for comprehensive NTD control including schistosomiasis is reaching all at-risk populations, including those hard to reach. Main access barriers include geographic, social and economic conditions. Objective : This scoping literature review aims to document the epidemiology of schistosomiasis in children under 6 years of age living in hard-to-reach areas and populations. Methods : This review will adopt the five-stage scoping review process of identifying the research question, identifying relevant studies, study selection, charting data and collating, summarizing and reporting results. Electronic databases including Medline, Web of Science, Embase (Ovid), LILACS and African Journals OnLine (AJOL) will be searched for relevant articles. Two independent reviewers will screen identified articles using a two-stage approach of reviewing the title/abstract and then the full text of provisionally retained articles. Relevant literatures will be downloaded into EndNote X9 to maintain and manage citation and facilitate the overall review process. A meta-analysis will be conducted if indicated. Relevance : The results will provide insights into the burden of schistosomiasis among marginalized PSAC, aiming to produce evidence on the need for inclusion of this population when designing the expansion of preventive chemotherapy programs.

A Proposed Framework for Early Prediction of Schistosomiasis

Schistosomiasis is a neglected tropical disease that continues to be a leading cause of illness and mortality around the globe. The causing parasites are affixed to the skin through defiled water and enter the human body. Failure to diagnose Schistosomiasis can result in various medical complications, such as ascites, portal hypertension, esophageal varices, splenomegaly, and growth retardation. Early prediction and identification of risk factors may aid in treating disease before it becomes incurable. We aimed to create a framework by incorporating the most significant features to predict Schistosomiasis using machine learning techniques. A dataset of advanced Schistosomiasis has been employed containing recovery and death cases. A total data of 4316 individuals containing recovery and death cases were included in this research. The dataset contains demographics, socioeconomic, and clinical factors with lab reports. Data preprocessing techniques (missing values imputation, outlier removal, data normalisation, and data transformation) have also been employed for better results. Feature selection techniques, including correlation-based feature selection, Information gain, gain ratio, ReliefF, and OneR, have been utilised to minimise a large number of features. Data resampling algorithms, including Random undersampling, Random oversampling, Cluster Centroid, Near miss, and SMOTE, are applied to address the data imbalance problem. We applied four machine learning algorithms to construct the model: Gradient Boosting, Light Gradient Boosting, Extreme Gradient Boosting and CatBoost. The performance of the proposed framework has been evaluated based on Accuracy, Precision, Recall and F1-Score. The results of our proposed framework stated that the CatBoost model showed the best performance with the highest accuracy of (87.1%) compared with Gradient Boosting (86%), Light Gradient Boosting (86.7%) and Extreme Gradient Boosting (86.9%). Our proposed framework will assist doctors and healthcare professionals in the early diagnosis of Schistosomiasis.

Intestinal schistosomiasis among secondary school students in Northern Tanzania: prevalence, infection intensity and associated risk factors

Objective

Our study investigated the prevalence, infection intensity and associated risk factors of intestinal schistosomiasis among secondary school students in Shinyanga Municipal Council, Northern Tanzania.

Methods

A quantitative school-based cross-sectional study was conducted from June to August 2022 among 620 secondary students. One stool specimen per participant was collected and screened for Schistosoma mansoni ova by microscopy using the Kato-Katz technique. Ova were counted to estimate infection intensity in all positive stool samples. Participants' socio-demographic characteristics and risk factors for intestinal schistosomiasis were gathered using a structured questionnaire. Data analysis consisted of descriptive statistics, Chi-square test and logistic regression.

Results

Overall prevalence of S. mansoni was 1.9%. All infected participants had light infection intensity. Overall prevalence of other intestinal parasites was 2.7%, with Hookworm spp (17.6%) and Entamoeba coli (52.9%) the most observed intestinal helminth and protozoa, respectively. Among assessed factors, being in form II or III, visiting water sources and doing activities in water sources were statistically significantly associated with increased risk of S. mansoni transmission.

Conclusions

There is ongoing transmission of intestinal schistosomiasis among secondary students. Hence, the need for extending praziquantel administration in this group, health education provision, and improvement of water supply, sanitation and hygienic practices.

Effect of Schistosoma haematobium infection on the cognitive functions of preschool age children and benefits of treatment from an endemic area in Zimbabwe

Background

Schistosomiasis is known to affect the cognitive functions of children, however, but there is paucity of information on its impact on early childhood development in developing countries where the disease is endemic. This study aimed at determining the effects of schistosomiasis due to Schistosoma haematobium on early childhood development in children below 5 years old from Murewa District, Zimbabwe, including the benefits of treatment.

Methods

Preschool age children (PSAC) under the age of 5 years were screened at baseline and at 6 months post-treatment for S. haematobium infections diagnosed using the urine filtration method. Cognitive domains were assessed using the Griffith Mental Developmental Scales III on 136 PSAC. Multivariate logistic regression was used to determine the level of association between S. haematobium infection and performance in the cognitive domains adjusting for confounding factors (i.e. nutrition, hemoglobin levels, gender and age). Median Development Quotient scores of each cognitive domain at baseline and at 6 months post-treatment were compared and quantified.

Results

After adjusting for confounding factors, PSAC infected with S. haematobium had greater odds of having lower scores in the Foundation of Learning Domain (OR = 3.9, p = 0.008), Language and Communication Domain (OR = 3.2, p = 0.017), Eye-Hand Coordination Domains (OR = 10.7, p = 0.001), Personal-Social-Emotional Domain (19.3, p = 0.001) and in the Overall General Development Domain (7.2, p = 0.011). Improvement of cognitive performance was observed at 6 months post treatment in the following Domains; Language and Communication Domain (p = 0.003), Eye-Hand Coordination Domain (p = 0.02) and General Development Domain (p = 0.006).

Conclusion

The study showed that S. haematobium infection in PSAC is associated with lower cognitive scores in the Foundation of Learning, Language and Communication, Eye-Hand Coordination, Personal-Social-Emotional and in the Overall General Development domains. Our results strengthen the call for inclusion of PSAC in routine deworming programs for the control of urinary schistosomiasis and the need to develop locally validated tools to monitor early child development in endemic areas where resources are limited.

Patient journey and resources mapping to implement a praziquantel mass drug administration program for children aged 5 years and below in resource-limited settings

BACKGROUND

The early childhood development of millions of children in some low- and medium-income countries may be compromised by schistosomiasis infections contracted at the age of 5 years and below. Currently, there are no standard guidelines for treating schistosomiasis in children that are 5 years and younger using praziquantel (PZQ), the only drug that the World Health Organization (WHO) recommends for treating schistosomiasis. The review is on processes and resources involved in the treatment of schistosomiasis in children aged 5 years and below.

METHODS

An electronic search for peer-reviewed articles published in the period from January 2011 to August 2021 was done in the Academic Search Complete, CINAHL with Full Text, Health Source: Nursing/Academic Edition, and MEDLINE databases via EBSCOHost and Google Scholar databases. The search targeted journals that described the treatment of schistosomiasis in children 5 years and below using praziquantel.

RESULTS

Thirteen studies met the inclusion criteria. The patient journey for treating schistosomiasis in children aged 5 years old and below using PZQ included the following activities: enrolment of the children into the treatment program; clinical examination; diagnosis; taking anthropometric measurements; feeding the children, making the PZQ palatable to the children; administration of PZQ; and monitoring of side effects. There was also a variation in the resources used to treat children aged 5 and below for schistosomiasis.

CONCLUSIONS

A PZQ mass drug administration program for children aged 5 years old and below in endemic areas should exclude the diagnosis of schistosomiasis before treatment. The resources required in the treatment process should be affordable, and should not require skills and maintenance resources that are beyond those that are available at the primary healthcare level.

Development of the Sm14/GLA-SE Schistosomiasis Vaccine Candidate: An Open, Non-Placebo-Controlled, Standardized-Dose Immunization Phase Ib Clinical Trial Targeting Healthy Young Women

We report the successful closure of Phase I clinical trials, comprising Phases Ia and Ib, of the vaccine candidate against human schistosomiasis: the Schistosoma mansoni 14 kDa fatty acid-binding protein (Sm14) + glucopyranosyl lipid A in squalene emulsion (GLA-SE). Shown here are the results of Phase Ib, an open, non-placebo-controlled, standardized-dose immunization trial involving 10 healthy 18-49-year-old women. Fifty micrograms of the Sm14 protein plus 10 µg GLA-SE per dose was given intramuscularly thrice at 30-day intervals. Participants were assessed clinically, biochemically, and immunologically for up to 120 days. In preambular experiments involving vaccinated pregnant female rabbits, we did not find any toxicological features in either the offspring or mothers, and the vaccine induced adaptive immunity in the animals. In women, no adverse events were observed, and vaccination induced high titers of anti-Sm14 serum IgG antibody production. Vaccination also elicited robust cytokine responses, with increased TNFα, IFNγ, and IL-2 profiles in all vaccinees on days 90 and 120. The completion of Phase I clinical trials, which were performed to the highest standards set by Good Clinical Research Practice (GCP) standards, and preclinical data in pregnant rabbits enabled the vaccine candidate to proceed to Phase II clinical trials in endemic areas.

Prevalence Mapping of Schistosoma mansoni Among Pre-school Age Children in Rwanda

Schistosoma mansoni is endemic in Rwanda, and control programs have been implemented with a special focus on school-age children (SAC), ignoring pre-school age children (pre-SAC) for which the actual prevalence of the disease is not well established. This study consisted of a cross-sectional quantitative mapping of the distribution of Schistosoma mansoni and identification of associated risk factors among pre-SAC throughout the country. The study covered all the 17 districts of Rwanda endemic for Schistosoma mansoni, with a total sample of 4,675 children enrolled from 80 purposively selected villages. The parasitological assessment of children's urine and stool samples was conducted using CCA and Kato Katz methods, respectively, for infection detection. A standard questionnaire was used to collect data on the risk factors, and geospatial assessment was performed using tablets and GPS to record geographic coordinates for plotting locations on maps using ArcGIS software. The overall prevalence of S. mansoni infection across the surveyed areas was 24 and 0.8% by CCA and Kato-Katz, respectively. Infection was significantly associated with bathing children in open water bodies. Furthermore, pre-SAC looked after by siblings (sisters) were two times as much likely to be infected compared to those looked after by mothers. Schistosomiasis control interventions are needed for pre-SAC to limit their exposure to open water bodies with expectations of adapted chemotherapy to be availed. Community-based deworming campaigns may be the best way to ensure good treatment coverage of pre-SAC in Rwanda.

Prevalence and risk factors of urogenital schistosomiasis among under-fives in Mtama District in the Lindi region of Tanzania

Introduction

Despite the ongoing intervention for schistosomiasis control among school-age children in the Lindi region of Tanzania, urogenital schistosomiasis continues to be a public health problem, presumably because other at-risk populations are not covered in praziquantel deworming campaigns. Evidence shows that under-fives become infected in their early life hence the need to understand the disease profile and the risk factors for exposure to infection so as to plan effective control strategies in this group. This study examined the prevalence and risk factors of urogenital schistosomiasis among under-fives in the Mtama district, Lindi region of Tanzania.

Methodology/Principal findings

A quantitative community-based cross-sectional study was carried out among 770 participants (385 under-fives and their 385 parents/guardians) in the Mtama district to investigate the burden and the risk factors associated with S. haematobium infection. A single urine specimen was collected from the under-fives and tested for macro and microhaematuria, presence of S. haematobium ova, and intensity of infection. A structured questionnaire gathered on risk factors for S. haematobium exposure in under-fives from their parents/guardians. Data analysis was performed using descriptive statistics, chi-square test, and logistic regression.

Prevalence of S. haematobium ova was 16.9%, and that of macro and microhaematuria was 6% and 17.9%, respectively. Of the 65 positive under-fives, 49 (75.4%) 95% CI 65.4–86.3 had a light infection intensity, and 16 (24.6%) 95% CI 13.7–35.5 had a heavy infection intensity. Among the assessed risk factors, the parents/guardians habit of visiting water bodies for domestic routines (AOR: 1.44, 95% CI: 1.13–1.74), especially the river (AOR: 6.00, 95% CI: 1.20–35.12), was found to be a significant risk factor for infection of S. haematobium in under-fives.

Conclusion/Significance

A moderate prevalence of S. haematobium was found among the under-fives conceivably with adverse health events. The infected under-fives could be a source of continuity for transmission in the community. An intervention that covers this group is necessary and should be complemented with regular screening, health education campaigns, and an adequate supply of safe water.

Urogenital schistosomiasis caused by S. haematobium has been highly endemic in Lindi-Tanzania for more than three decades. Due to the burden of the disease, preventive chemotherapy with praziquantel was put in place to control the infection. However, this intervention has focused merely on school-aged children, excluding preschool-age children, despite the evidence of early exposure to the infested water. A community-based cross-sectional study was conducted to investigate the current burden and the risk factors of urogenital schistosomiasis among the under-fives of Mtama district, Lindi region. The prevalence of urogenital schistosomiasis in under-fives was 16.9% with approximately a quarter (24.6%) being heavily infected. The factors responsible for the ongoing transmission of urogenital schistosomiasis in under-fives were the parental/guardians’ inadequate knowledge (31.1%), coupled with negative attitudes (40.5%), and inappropriate practices (34.3%) regarding the disease transmission, treatment, and prevention. Also, inadequate supply of safe water and sanitation facilities, unhygienic practices, and intense parental/guardian water contact activities. The parents/guardians’ practices of visiting the water bodies, especially the river, with the under-fives were significantly associated with the early acquisition of the disease. Hence, there is a need for regular monitoring of under-fives, provision of health education to parents/guardians, and adequate provision of safe water.

Screening for parasites in migrant children

BACKGROUND

Globalization has pushed population movements in the last decades, turning imported diseases into the focus. Due to behavioral habits, children are at higher risk of acquiring iparasitosis. This study aims to investigate the prevalence of parasites in migrant children and factors associated with parasitic diseases.

METHOD

Retrospective cross-sectional study (2014-2018) including children diagnosed with parasitosis. The diagnosis was based on serology and/or microscopic stool-sample evaluation. Epidemiological and clinical data were recorded.

RESULTS

Out of 813 migrant children screened, 241 (29.6%) presented at least one parasite, and 89 (10.9%) more than one. The median age was 6.6 years (IQR: 3.1-11.9) and 58.9% were males. Most cases were referred for a health exam; only 52.3% of children were symptomatic, but 43.6% had eosinophilia. The most common diagnosis were giardiasis (35.3%), schistosomiasis (19.1%), toxocariasis (15.4%), and strongyloidiasis (9.1%). After the multivariate analysis, African origin and presenting with eosinophilia were the main risk factors for parasitism.

CONCLUSIONS

parasitosis are frequent among migrant children. Children are often asymptomatic, and thus active screening for parasitosis should be considered among high-risk populations. Eosinophilia can be useful to guide complimentary tests, as well as geographical origin, but normal eosinophil count does not exclude parasitosis.

Persistence of Schistosoma haematobium transmission among school children and its implication for the control of urogenital schistosomiasis in Lindi, Tanzania

Background

Despite twelve rounds of school-based preventive chemotherapy for schistosomiasis in endemic areas of Tanzania such as Mtama district, Lindi: the burden of Schistosoma haematobium infection has remained highly conceivable due to re-infections. The factors associated with continuity of S.haematobium transmission in Mtama district, Lindi have not been fully established. This study investigated the burden and factors contributing to the ongoing transmission of S.haematobium infection in the endemic district of Mtama, Lindi.

Methods

A quantitative cross-sectional survey was carried out among 649 school-age children in the Mtama district to determine the burden and factors associated with continuity of S.haematobium infection transmission. A single urine specimen was obtained from each pupil and tested for macro- and microhaematuria, presence of S.haematobium ova, as well intensity of infection; this was complemented with a survey of Bulinus spp snail intermediate hosts and their infectivity. A structured questionnaire was employed to gather information on individual and environmental risk factors for S.haematobium transmission. Summary statistics were computed for individual variables; while a univariate and multivariate logistic regression analysis was performed to assess the association between risk factors with S.haematobium infection.

Results

Prevalence of S.haematobium infection by macro- and microhaematuria was 13.1% and 46.2% respectively. The prevalence of S.haematobium ova was 52.7%; intensity of infection was light in 53.1%, and heavy in 46.9%. Snail intermediate hosts were Bulinus globosus and B.nasutus, whose infectivity was 2.2% and 1.3%, respectively. Among the assessed risk factors, long residency (10–13 years) in the area was a significant risk factor for the continuity of S.haematobium transmission (AOR: 21.79, 95% CI: 1.37–346.4).

Conclusions

The observed 52.7% prevalence of S.haematobium infection represents unacceptably high prevalence after 12 rounds of preventive chemotherapy. Therefore, an urgent need for the implementation of integrated multiple control interventions in the Mtama district; is considered to be imperative.

Schistosomiasis outbreak during COVID-19 pandemic in Takum, Northeast Nigeria: Analysis of infection status and associated risk factors

BACKGROUND

Mass drug administration for schistosomiasis started in 2014 across Taraba State. Surprisingly in 2020, an outbreak of schistosomiasis was reported in Takum local government area. This epidemiological investigation therefore assessed the current status of infection, analyzed associated risk factors and arrested the outbreak through community sensitization activities and mass treatment of 3,580 persons with praziquantel tablets.

METHODS

Epidemiological assessment involving parasitological analysis of stool and urine samples were conducted among 432 consenting participants in five communities. Samples were processed using Kato-Katz and urine filtration techniques. Participants data on demography, water contact behavior and access to water, sanitation and hygiene facilities were obtained using standardized questionnaires. Data were analysed using SPSS 20.0 and significance level was set at 95%.

RESULTS

An overall prevalence of 34.7% was observed, with 150 participants infected with both species of Schistosoma parasite. By communities, prevalence was higher in Birama (57.7%), Barkin Lissa (50.5%) and Shibong (33.3%). By species', S. haematobium infection was significantly higher than S. mansoni (28.9% vs 9.5%), with higher proportion of younger males infected (p<0.05). The condition of WASH is deplorable. About 87% had no latrines, 67% had no access to improved source of potable water and 23.6% relied on the river as their main source of water. Infections was significantly associated with water contact behaviors like playing in water (OR:1.50, 95% CI: 1.01-2.25) and swimming (OR:1.55, 95% CI: 1.04-2.31).

CONCLUSION

It is important to reclassify the treatment needs of Takum LGA based on the findings of this study. Furthermore, efforts targeted at improving access to WASH, reducing snail population, improving health education and strengthening surveillance systems to identify schistosomiasis hotspots will be a step in the right direction.

Improving anthelmintic treatment for schistosomiasis and soil-transmitted helminthiases through sharing and reuse of individual participant data

The Infectious Diseases Data Observatory (IDDO, https://www.iddo.org) has launched a clinical data platform for the collation, curation, standardisation and reuse of individual participant data (IPD) on treatments for two of the most globally important neglected tropical diseases (NTDs), schistosomiasis (SCH) and soil-transmitted helminthiases (STHs). This initiative aims to harness the power of data-sharing by facilitating collaborative joint analyses of pooled datasets to generate robust evidence on the efficacy and safety of anthelminthic treatment regimens. A crucial component of this endeavour has been the development of a Research Agenda to promote engagement with the SCH and STH research and disease control communities by highlighting key questions that could be tackled using data shared through the IDDO platform. Here, we give a contextual overview of the priority research themes articulated in the Research Agenda-a 'living' document hosted on the IDDO website-and describe the three-stage consultation process behind its development. We also discuss the sustainability and future directions of the platform, emphasising throughout the power and promise of ethical and equitable sharing and reuse of clinical data to support the elimination of NTDs.

Medullary neuroschistosomiasis in a pediatric patient: a case report

A pediatric patient with neurological deficit was examined using magnetic resonance imaging (MRI]. The images revealed abnormal signal intensity and enhancement of the spinal cord, indicating myelopathy. Identifying the cause of the myelopathy required a differential diagnosis. Images from MRI included a pre-contrast T1 weighted sagittal sequence, which revealed expansion of the distal lumbar spinal cord and conus medullaris from T10-L1. The T2 weighted sagittal sequence revealed patchy areas of hyperintense signal. We did not notice any chronic hemorrhagic products or cysts. Within the field of view, we saw multifocal areas of bladder wall thickening. Sagittal and axial T1 weighted post gadolinium images demonstrated mixed linear and nodular patchy enhancement of the conus medullaris predominantly anteriorly and along the anterior surface of the meninges. On the 18 day of hospitalization, a spinal biopsy revealed the presence of granuloma with non-viable bilharzia ova, and schistosomiasis of the spinal cord was diagnosed. Although uncommon, when it does occur, schistosomiasis has significant implications. Using MRI, the medical team noticed abnormal features that called for a biopsy, and were thus able to differentiate between medullary schistosomiasis and other infective/inflammatory conditions. A prompt diagnosis is vital for initiating early treatment, and avoiding complications and invasive surgery.

Efficacy and Safety of New Orodispersible Tablet Formulations of Praziquantel (Racemate and L-Praziquantel) in Schistosoma mansoni-Infected Preschool-Age Children and Infants: A Randomized Dose-Finding Phase 2 Study

Introduction

Two novel formulations of praziquantel (PZQ) and Levo-(L-)PZQ (arpraziquantel) have been developed for the treatment of schistosomiasis in preschool-age children and infants.

Methods

This open-label, dose-finding Phase 2 study assessed the efficacy and safety of PZQ formulations in children and infants infected with Schisostoma mansoni in Côte d’Ivoire. In Part 1, 420 children aged 2.1–6.9 years (weight 10.0–29.9 kg) were enrolled and randomized to one of 7 treatment arms (n=60 per arm): commercially available racemate (rac)-PZQ at 3x20 mg/kg or 40 mg/kg (treatment arms 1 and 2); rac-PZQ orodispersible tablet (ODT) at 40 mg/kg or 60 mg/kg (treatment arms 3 and 4); or L-PZQ ODT at 30 mg/kg, 45 mg/kg, or 60 mg/kg (treatment arms 5, 6, and 7). The optimal formulation and dose identified (L-PZQ ODT 50 mg/kg) was used in Part 2, which enrolled 24 infants aged 6–24 months (weight 7.5–14.8 kg). Infants were treated in an age-staggered approach: age 13–24 months (treatment arm 8, n=20) and age 6–12 months (treatment arm 9, n=4). The primary endpoint was clinical cure rate (CR) demonstrated by the Kato–Katz method 14–21 days post-treatment. Secondary endpoints included CR by point-of-care circulating cathodic antigen, egg reduction rate (ERR), and adverse events (AEs).

Results

In Part 1, CRs ≥70% were achieved in all treatment arms and were highest with L-PZQ ODT 60 mg/kg (89.7%), rac-PZQ 3x20 mg/kg (89.5%), and L-PZQ ODT 45 mg/kg (86.0%). In Part 2, CRs were &gt;90%. All treatment arms had ERRs &gt;95%. Treatment-related AEs were reported by 71 participants (16.0%) and were similar across treatment arms; most were mild and transient. The most common treatment-emergent AEs were laboratory abnormalities. No deaths or discontinuation due to treatment-emergent AEs were reported and no new safety concerns were identified.

Conclusion

New rac-PZQ and L-PZQ ODT formulations used as single-dose therapy against S. mansoni demonstrated acceptable overall efficacy and safety in preschool-age children and infants, warranting further studies in this population.

Clinical Trial Registration

ClinicalTrials.gov, identifier NCT02806232; Pan African Clinical Trials Registry, identifier PACTR201604001493593.

Algorithm for diagnosis of early Schistosoma haematobium using prodromal signs and symptoms in pre-school age children in an endemic district in Zimbabwe

Introduction

Prompt diagnosis of acute schistosomiasis benefits the individual and provides opportunities for early public health intervention. In endemic areas schistosomiasis is usually contracted during the first 5 years of life, thus it is critical to look at how the infection manifests in this age group. The aim of this study was to describe the prodromal signs and symptoms of early schistosomiasis infection, correlate these with early disease progression and risk score to develop an easy to use clinical algorithm to identify early Schistosoma haematobium infection cases in resource limited settings.

Methodology

Two hundred and four, preschool age children who were lifelong residence of a schistosomiasis endemic district and at high risk of acquiring schistosomiasis were followed up from July 2019 to December 2019, during high transmission season. The children received interval and standard full clinical evaluations and laboratory investigations for schistosomiasis by clinicians blinded from their schistosomiasis infection status. Diagnosis of S. haematobium was by urine filtration collected over three consecutive days. Signs and symptoms of schistosomiasis at first examination visit were compared to follow-up visits. Signs and symptoms common on the last schistosomiasis negative visit (before a subsequent positive) were assigned as early schistosomiasis infection (ESI), after possible alternative causes were ruled out. Logistic regression identified clinical predictors. A model based score was assigned to each predictor to create a risk for every child. An algorithm was created based on the predictor risk scores and validated on a separate cohort of 537 preschool age children.

Results

Twenty-one percent (42) of the participants were negative for S. haematobium infection at baseline but turned positive at follow-up. The ESI participants at the preceding S. haematobium negative visit had the following prodromal signs and symptoms in comparison to non-ESI participants; pruritic rash adjusted odds ratio (AOR) = 21.52 (95% CI 6.38–72.66), fever AOR = 82 (95% CI 10.98–612), abdominal pain AOR = 2.6 (95% CI 1.25–5.43), pallor AOR = 4 (95% CI 1.44–11.12) and a history of facial/body swelling within the previous month AOR = 7.31 (95% CI 3.49–15.33). Furthermore 16% of the ESI group had mild normocytic anaemia, whilst 2% had moderate normocytic anaemia. A risk score model was created using a rounded integer from the relative risks ratios. The diagnostic algorithm created had a sensitivity of 81% and a specificity of 96.9%, Positive predictive value = 87.2% and NPV was 95.2%. The area under the curve for the algorithm was 0.93 (0.90–0.97) in comparison with the urine dipstick AUC = 0.58 (0.48–0.69). There was a similar appearance in the validation cohort as in the derivative cohort.

Conclusion

This study demonstrates for the first time prodromal signs and symptoms associated with early S. haematobium infection in pre-school age children. These prodromal signs and symptoms pave way for early intervention and management, thus decreasing the harm of late diagnosis. Our algorithm has the potential to assist in risk-stratifying pre-school age children for early S. haematobium infection. Independent validation of the algorithm on another cohort is needed to assess the utility further.

Schistosoma haematobium causes urogenital infection and in endemic areas schistosomiasis is usually contracted during the first 5 years of life, thus it is critical to look at how the infection manifests in this age group. Prompt diagnosis of acute schistosomiasis is required to benefit the individuals and provide opportunities for early treatment and public health intervention. The study examined symptoms that correlated with early disease progression and risk scored to develop an easy to use clinical algorithm to identify early S. haematobium infection cases. The children received standard full clinical evaluations by clinicians who were blinded from schistosomiasis diagnosis by parasitological examination. An algorithm was created based on the predictor risk scores and participants had the following prodromal signs and symptoms; pruritic rash, abdominal pain, pallor, abdominal pain, inguinal lymphadenopathy and a history of facial/body swelling within the previous month. A risk score model, diagnostic algorithm, was created that compared to urine dipstick and parasitology. This study demonstrates the clinical signs and symptoms associated with early S. haematobium infection in pre-school age children. These prodromal signs and symptoms pave way for early intervention and management, thus decreasing the harm of late diagnosis common in populations from endemic areas.

Direct Powder Extrusion 3D Printing of Praziquantel to Overcome Neglected Disease Formulation Challenges in Paediatric Populations

For the last 40 years, praziquantel has been the standard treatment for schistosomiasis, a neglected parasitic disease affecting more than 250 million people worldwide. However, there is no suitable paediatric formulation on the market, leading to off-label use and the splitting of commercial tablets for adults. In this study, we use a recently available technology, direct powder extrusion (DPE) three-dimensional printing (3DP), to prepare paediatric Printlets™ (3D printed tablets) of amorphous solid dispersions of praziquantel with Kollidon^® VA 64 and surfactants (Span™ 20 or Kolliphor^® SLS). Printlets were successfully printed from both pellets and powders obtained from extrudates by hot melt extrusion (HME). In vitro dissolution studies showed a greater than four-fold increase in praziquantel release, due to the formation of amorphous solid dispersions. In vitro palatability data indicated that the printlets were in the range of praziquantel tolerability, highlighting the taste masking capabilities of this technology without the need for additional taste masking excipients. This work has demonstrated the possibility of 3D printing tablets using pellets or powder forms obtained by HME, avoiding the use of filaments in fused deposition modelling 3DP. Moreover, the main formulation hurdles of praziquantel, such as low drug solubility, inadequate taste, and high and variable dose requirements, can be overcome using this technology.

Unveiling the Potential of Purinergic Signaling in Schistosomiasis Treatment

Schistosomiasis is a neglected tropical disease. It is related to long-lasting granulomatous fibrosis and inflammation of target organs, and current sub-optimal pharmacological treatment creates global public health concerns. Intravascular worms and eggs release antigens and extracellular vesicles that target host endothelial cells, modulate the immune system, and stimulate the release of damageassociated molecular patterns (DAMPs). ATP, one of the most studied DAMPs, triggers a cascade of autocrine and paracrine actions through purinergic P2X and P2Y receptors, which are shaped by ectonucleotidases (CD39). Both P2 receptor families, and in particular P2Y₁, P2Y₂, P2Y₁₂, and P2X7 receptors, have been attracting increasing interest in several inflammatory diseases and drug development. Current data obtained from the murine model unveiled a CD39-ADP-P2Y₁/P2Y₁₂ receptors signaling pathway linked to the liver and mesenteric exacerbations of schistosomal inflammation. Therefore, we proposed that members of this purinergic signaling could be putative pharmacological targets to reduce schistosomal morbidity.

Prevalence of intestinal schistosomiasis in pre-school aged children: a pilot survey in Marolambo District, Madagascar

School-aged children (SAC) have a considerable burden of intestinal schistosomiasis in Madagascar yet its burden in pre-school aged children (PSAC) is currently overlooked. To assess the at-risk status of PSAC, we undertook a pilot epidemiological survey in June 2019 examining children (n = 89), aged 2–4-years of balanced gender, in six remote villages in Marolambo District, Madagascar. Diagnosis included use of urine-circulating cathodic antigen (CCA) dipsticks and coproscopy of stool with duplicate Kato-Katz (K-K) thick smears. Prevalence of intestinal schistosomiasis by urine-CCA was 67.4% (95% confidence interval [CI]: 56.5–77.2%) and 35.0% (95% CI: 24.7–46.5%) by K-K. The relationship between faecal eggs per gram (epg) and urine-CCA G-scores (G1 to G10) was assessed by linear regression modelling, finding for every increment in G-score, epg increased by 20.4 (6.50–34.4, P = 0.006). Observed proportions of faecal epg intensities were light (78.6%), moderate (17.9%) and heavy (3.6%). Soil-transmitted helminthiasis was noted, prevalence of ascariasis was 18.8% and trichuriasis was 33.8% (hookworm was not reported). Co-infection of intestinal schistosomiasis and soil-transmitted helminthiasis occurred in 36.3% of PSAC. These results provide solid evidence highlighting the overlooked burden of intestinal schistosomiasis in PSAC, and they also offer technical  guidance for better surveillance data for the Madagascan national control programme.

Comparison of POC-CCA with Kato-Katz in Diagnosing Schistosoma mansoni Infection in a Pediatric L-Praziquantel Clinical Trial

Introduction

Traditionally Schistosoma mansoni infection is diagnosed by the Kato-Katz method. Thick smears from each stool sample are prepared on slides and eggs are counted microscopically. Commercially available point-of-care circulating cathodic antigen (POC-CCA) cassette tests detect schistosomiasis antigens from urine samples in 20 minutes. POC-CCA results are qualitative or semi-quantitative: signal intensity is an indicator of the amount of worm antigens in the sample. Both methods were used in a phase II trial investigating the efficacy and safety of new pediatric formulations of praziquantel (PZQ) among children ≤6 years (NCT02806232). This secondary analysis evaluated the consistency of results between the Kato-Katz and POC-CCA methods.

Methods

POC-CCA was used to pre-screen for S. mansoni infection. Children with positive results were tested by the Kato-Katz method, and those with positive Kato-Katz results (&gt;1 egg/1 occurrence) were enrolled. Participants (N=444) were treated with different formulations and doses of PZQ. POC-CCA and Kato-Katz were performed at 2–3 weeks after treatment to evaluate drug efficacy. Cure rate (CR) was defined as the proportion of participants with a negative result per POC-CCA, or no eggs in the stool samples per Kato-Katz. Kappa statistic was used to assess the agreement on cure status, and Spearman correlation between POC-CCA positivity and Kato-Katz egg counts was evaluated. Sensitivity and specificity of POC-CCA were calculated using Kato-Katz as a reference standard.

Results

CR per POC-CCA, measured 2–3 weeks after treatment, was 52% [95% confidence interval (CI): 48%, 57%] across all treatment arms except in infants aged 3–12 months. CR per Kato-Katz was 83% (95% CI: 79%, 87%). Kappa statistic was 0.16 (95% CI: 0.09, 0.23), indicating that the agreement was slightly better than by chance. Relative to Kato-Katz, POC-CCA’s sensitivity to detect infection was 70% and specificity was 57%. Spearman correlation coefficient between POC-CCA positivity and Kato-Katz egg counts was 0.26 (95% CI: 0.17, 0.34).

Conclusion

POC-CCA is sensitive and rapid for diagnosing S. mansoni infection, but its performance and consistency with Kato-Katz requires further investigation among young children.

Comparative palatability of orally disintegrating tablets (ODTs) of Praziquantel (L-PZQ and Rac-PZQ) versus current PZQ tablet in African children: A randomized, single-blind, crossover study

BACKGROUND

Praziquantel (PZQ) is currently the only recommended drug for infection and disease caused by the schistosome species that infects humans; however, the current tablet formulation is not suitable for pre-school age children mainly due to its bitterness and the large tablet size. We assessed the palatability of two new orally disintegrating tablet (ODT) formulations of PZQ.

METHODOLOGY

This randomized, single-blind, crossover, swill-and-spit palatability study (NCT02315352) was carried out at a single school in Tanzania in children aged 6-11 years old, with or without schistosomiasis infection as this was not part of the assessment. Children were stratified according to age group (6-8 years or 9-11 years) and gender, then randomized to receive each formulation in a pre-specified sequence. Over 2 days, the children assessed the palatability of Levo-Praziquantel (L-PZQ) ODT 150 mg and Racemate Praziquantel (Rac-PZQ) ODT 150 mg disintegrated in the mouth without water on the first day, and L-PZQ and Rac-PZQ dispersed in water and the currently available PZQ 600 mg formulation (PZQ-Cesol) crushed and dispersed in water on the second day. The palatability of each formulation was rated using a 100 mm visual analogue scale (VAS) incorporating a 5-point hedonic scale, immediately after spitting out the test product (VASt = 0 primary outcome) and after 2-5 minutes (VASt = 2-5).

PRINCIPAL FINDINGS

In total, 48 children took part in the assessment. Overall, there was no reported difference in the VASt = 0 between the two ODT formulations (p = 0.106) without water. Higher VASt = 0 and VASt = 2-5 scores were reported for L-PZQ ODT compared with Rac-PZQ ODT in older children (p = 0.046 and p = 0.026, respectively). The VASt = 0 and VASt = 2-5 were higher for both ODT formulations compared with the standard formulation (p<0.001 for both time points). No serious adverse events were reported.

CONCLUSIONS/SIGNIFICANCE

The new paediatric-friendly formulations dispersed in water were both found to be more palatable than the existing standard formulation of PZQ. There may be gender and age effects on the assessment of palatability. Further research is needed for assessing efficacy and tolerability of the newly ODTs Praziquantel drug in younger children.

TRIAL REGISTRATION

The trial was registered on ClinicalTrials.gov (NCT02315352) and in the Pan African Clinical Trials Registry (PACTR201412000959159).

Haematuria in children

Haematuria is a common finding in children and can be macroscopic or microscopic. In contrast to adults, haematuria in children very rarely indicates an underlying malignant pathology. The differential diagnosis is broad, with the most common underlying causes being infection, glomerulonephritis and hypercalciuria. It is useful to distinguish between nephrological or upper urinary tract and lower urinary tract pathologies, as this will guide investigations and referral. This review discusses the causes of haematuria in the paediatric population.

Effects of TNF-α and IL-10-819 T>C single nucleotide polymorphisms on urogenital schistosomiasis in preschool children in Zimbabwe

Background

Knowledge gaps exist between host genetic factors and susceptibility to schistosomiasis.

Objective

This study determined cytokine levels and single nucleotide polymorphisms of tumour necrosis factor (TNF)-α (rs1800629) and interleukin (IL)-10 (rs1800871) and their possible impact on susceptibility to schistosomiasis in preschool-age children in the Madziva area of Shamva district, Mashonaland Central province, Zimbabwe.

Methods

Urogenital schistosomiasis was diagnosed using the urine filtration method, while a sandwich enzyme-linked immunosorbent assay was used for cytokine level determination. The survey was done in August 2015 and reinfection levels post treatment were assessed at 3, 6 and 12 months. Amplification refractory mutation system polymerase chain reaction with visualisation on 2% agarose gel electrophoresis was used for genotyping.

Results

Schistosomiasis prevalence was found to be 10.5% (59/563). Reinfections were detected in only six children at 3 months and only one was reinfected at 12 months. There were no significant differences in TNF-α-308 G/A allele or genotype frequencies between the Schistosoma haematobium infected participants (p = 0.360) and uninfected participants (p = 0.279). However, no children with the IL-10-819 TT genotype had schistosomiasis. The TNF-α GG genotype corresponded with significantly lower TNF-α levels when compared with the GA or AA genotypes (p < 0.001), and TNF-α levels were significantly lower in infected children compared to uninfected children (p < 0.001).

Conclusion

Higher TNF-α levels and lower IL-10 levels are potentially protective against schistosomiasis infection. The IL-10-819 TT genotype is potentially protective against infection through its association with lower IL-10 levels.

Prevalence, infection intensity and geographical distribution of schistosomiasis among pre-school and school aged children in villages surrounding Lake Nyasa, Tanzania

Planning and implementation of schistosomiasis control activities requires an understanding of the prevalence, intensity of infection and geographical distribution of the disease in different epidemiological settings. Although, Tanzania is known to be highly endemic to schistosomiasis, there is paucity of data on the geographical distribution of schistosomiasis in potential large water bodies in the country. Thus, the present study was conducted to determine the prevalence, infection intensities and geographical distribution of schistosomiasis along villages located on the shoreline of Lake Nyasa, southern Tanzania. A cross-sectional study was conducted among 1560 children aged 1–13 years old living in villages located along the shoreline of Lake Nyasa. A single urine and stool sample was obtained from each participating child and screened for S.mansoni using Kato Katz (KK) technique to detect eggs and using point-of-care circulating Cathodic Antigen (POC-CCA) test to detect antigen in urine. Urine filtration technique was used to screen for S.haematobium eggs in urine samples. Villages/primary school were mapped using geographical information system and prevalence map was generated using ArcView GIS software. The overall prevalence of S.mansoni based on KK technique and POC-CCA test was 15.1% (95%CI: 13.4–16.9) and 21.8% (95%CI: 18.5–25.3) respectively. The prevalence S.haematobium was 0.83% (95%CI: 0.5–1.4) and that of haematuria was 0.9%. The arithmetic mean egg intensities for S.haematobium and S.mansoni were 18.5 mean eggs/10 ml (95%CI: 5.9–57.6) of urine and 34.7 mean epg (95%CI: 27.7–41.7) respectively. Villages located on the southern end of the lake had significantly high prevalence of S.mansoni than those located on the northern part (χ² = 178.7838, P = 0.001). Cases of S.haematobium were detected only in three villages. Both S.mansoni and S.haematobium infections occur in villages located along the shoreline of Lake Nyasa at varying prevalence. These finding provide insights that can provide guidance in planning and implementation of MDA approach and other recommended measures such as improvement in sanitation, provision of clean water and behaviour changes through public health education.

Polarization of intestinal tumour-associated macrophages regulates the development of schistosomal colorectal cancer

Tumour-associated macrophages (TAMs) can be divided into M1 and M2 TAMs. M2 TAMs play an important role in tumor progression, promoting a pro-angiogenic and immunosuppressive signal in the tumor. Previous studies have shown a correlation between schistosomiasis and colorectal cancer (CRC), but the specific mechanism has not been clarified. The differences between schistosomal CRC and non-schistosomal CRC were explored by analysing the clinicopathological data and survival time prognosis of schistosomal CRC and non-schistosomal CRC patients. The underlying mechanisms leading to the differences were investigated via tissue pathology experiments. Here, we investigated whether TAMs play a role in schistosomal CRC, leading to different clinicopathological features and prognoses in schistosomal CRC and non-schistosomal CRC patients and whether TAMs have a regulatory effect on the development and prognosis of schistosomal CRC. We found that schistosomal CRC and non-schistosomal CRC patients differ in age, sex, TNM staging and prognosis survival. Applying a logistic regression analysis model, the results showed that age, sex, pathological T stage and combined schistosomiasis were independent risk factors for CRC. Prognostic analysis of follow-up patients with schistosomal CRC found that the T stage, M stage and M2 TAMs numbers were independent prognostic factors for overall survival (OS). TAMs are significantly higher in tissues of schistosomal CRC than in non-schistosomal CRC patients, especially M2 TAMs. Studies on schistosomal colorectal tissue found that the expression of M2 TAMs increased with the malignant process of intestinal tissue. In summary, schistosomal CRC and non-schistosomal CRC patients have different clinicopathological features and prognosis, schistosomiasis is a risk factor for CRC and M2 TAMs are independent prognostic factors for OS.

A systematic review and meta-analysis quantifying schistosomiasis infection burden in pre-school aged children (PreSAC) in sub-Saharan Africa for the period 2000-2020

INTRODUCTION

Following the adoption of the World Health Assembly Resolution WHA 65.21 and Neglected Tropical Diseases road map 2021-2030, schistosomiasis control programmes have shifted from morbidity control to disease elimination. However, several gaps continue to be observed in the implementation of control programmes with certain age groups omitted from these campaigns increasing health inequalities and risks of reinfections to previously treated groups. We used the Inverse Variance Heterogeneity (IVhet) model to estimate the prevalence of schistosomiasis infection among preschool-aged children.

METHODS

We did a systematic review of peer-reviewed literature on schistosomiasis in sub-Saharan Africa for the period January 1, 2000 to November 30, 2020. Quantitative data for cases of schistosomiasis infection were extracted, including country and region where the studies were done, year of publication and specific schistosome species observed. The IVhet model was used to estimate the pooled prevalence estimate (PPE), the heterogeneity and publication bias.

RESULTS

We screened 2601 articles to obtain 47 eligible studies containing quantitative data on preschool-aged children. Of the selected studies, 44.7% (n = 22) were from East Africa while the least number of studies obtained (2.1%, n = 1) was from Central Africa. 21712 subjects were screened for infection due to Schistosoma spp; 13924 for S. mansoni and 7788 for S. haematobium. The PPE for schistosomiasis among PreSAC was 19% (95% CI: 11-28). Infection due to S. mansoni (IVhet PPE: 22% (95% CI: 9-36) was higher than that due to S. haematobium (15%; 95% CI: 6-25). A Luis Furuya-Kanamori index of 1.83 indicated a lack of publication bias. High level of heterogeneity was observed (I2 > 90%) and this could not be reduced through subgroup analysis.

CONCLUSION

Schistosomiasis infection among pre-school aged children 6 years old and below is high. This indicates the importance of including this age group in treatment programmes to reduce infection prevalence and long-term morbidities associated with prolonged schistosome infection.

Parasite Population Genetic Contributions to the Schistosomiasis Consortium for Operational Research and Evaluation within Sub-Saharan Africa

Analyses of the population genetic structure of schistosomes under the "Schistosomiasis Consortium for Operational Research and Evaluation" (SCORE) contrasting treatment pressure scenarios in Tanzania, Niger, and Zanzibar were performed to provide supplementary critical information with which to evaluate the impact of these large-scale control activities and guide how activities could be adjusted. We predicted that population genetic analyses would reveal information on a range of important parameters including, but not exclusive to, recruitment and transmission of genotypes, occurrence of hybridization events, differences in reproductive mode, and degrees of inbreeding, and hence, the evolutionary potential, and responses of parasite populations under contrasting treatment pressures. Key findings revealed that naturally high levels of gene flow and mixing of the parasite populations between neighboring sites were likely to dilute any effects imposed by the SCORE treatment arms. Furthermore, significant inherent differences in parasite fecundity were observed, independent of current treatment arm, but potentially of major impact in terms of maintaining high levels of ongoing transmission in persistent "biological hotspot" sites. Within Niger, naturally occurring Schistosoma haematobium/Schistosoma bovis viable hybrids were found to be abundant, often occurring in significantly higher proportions than that of single-species S. haematobium infections. By examining parasite population genetic structures across hosts, treatment regimens, and the spatial landscape, our results to date illustrate key transmission processes over and above that which could be achieved through standard parasitological monitoring of prevalence and intensity alone, as well as adding to our understanding of Schistosoma spp. life history strategies in general.

Current Understanding of Immunity Against Schistosomiasis: Impact on Vaccine and Drug Development

Schistosomiasis is a neglected tropical disease inflicting significant morbidity in humans worldwide. The disease is caused by infections with a parasitic trematode belonging to the genus Schistosoma. Over 250 million people are currently infected globally, with an estimated disability-adjusted life-years of 1.9 million attributed to the disease. Current understanding, based on several immunological studies using experimental and human models of schistosomiasis, reveals that complex immune mechanisms play off each other in the acquisition of immune resistance to infection/reinfection. Nevertheless, the precise characteristics of these responses, the specific antigens against which they are elicited, and how these responses are intricately regulated are still being investigated. What is apparent is that immunity to schistosome infections develops slowly and over a prolonged period of time, augmented by the death of adult worms occurring naturally or by praziquantel therapy. In this review, aspects of immunity to schistosomiasis, host–parasite interactions and their impact on schistosomiasis vaccine development are discussed.

Association of Schistosoma haematobium infection morbidity and severity on co-infections in pre-school age children living in a rural endemic area in Zimbabwe

Background

Individuals living in Schistosoma haematobium endemic areas are often at risk of having other communicable diseases simultaneously. This usually creates diagnostic difficulties leading to misdiagnosis and overlooking of schistosomiasis infection. In this study we investigated the prevalence and severity of coinfections in pre-school age children and further investigated associations between S. haematobium prevalence and under 5 mortality.

Methods

A community based cross-sectional survey was conducted in Shamva District, Zimbabwe. Using random selection, 465 preschool age children (1–5 years of age) were enrolled through clinical examination by two independent clinicians for the following top morbidity causing conditions: respiratory tract infections, dermatophytosis, malaria and fever of unknown origin. The conditions and their severe sequels were diagnosed as per approved WHO standards. S. haematobium infection was diagnosed by urine filtration and the children were screened for conditions common in the study area which included HIV, tuberculosis, malnutrition and typhoid. Data was analysed using univariate and multinomial regression analysis and relative risk (RR) calculated.

Results

Prevalence of S. haematobium was 35% (145). The clinical conditions assessed had the following prevalence in the study population: upper respiratory tract infection 40% (229), fever of unknown origin 45% (189), dermatophytosis 18% and malaria 18% (75). The odds of co-infections observed with S. haematobium infection were: upper respiratory tract infection aOR = 1.22 (95% CI 0.80 to 1.87), dermatophytosis aOR = 4.79 (95% CI 2.78 to 8.25), fever of unknown origin aOR = 10.63 (95% CI 6.48–17.45) and malaria aOR = 0.91 (95% CI 0.51 to1.58). Effect of schistosomiasis coinfection on disease progression based on the odds of the diseases progressing to severe sequalae were: Severe pneumonia aOR = 8.41 (95% CI 3.09–22.93), p < 0.0001, complicated malaria aOR = 7.09 (95% CI 1.51–33.39), p = 0.02, severe dermatophytosis aOR = 20.3 (95% CI 4.78–83.20):p = 0.03, and fever of unknown origin aOR = 1.62 (95%CI 1.56–4.73), p = 0.02.

Conclusion

This study revealed an association between schistosomiasis and the comorbidity conditions of URTI, dermatophytosis, malaria and FUO in PSAC living in a schistosomiasis endemic area. A possible detrimental effect where coinfection led to severe sequels of the comorbidity conditions was demonstrated. Appropriate clinical diagnostic methods are required to identify associated infectious diseases and initiate early treatment of schistosomiasis and co-infections in PSAC.

Investigating a strategy for quantifying schistosome infection levels in preschool-aged children using prevalence data from school-aged children

In 2012, the World Health Organisation (WHO) set out a roadmap for eliminating schistosomiasis as a public health problem by 2025. To achieve this target, preschool-aged children (PSAC; aged 6 years and below) will need to be included in schistosomiasis treatment programmes. As the global community discusses the tools and approaches for treating this group, one of the main questions that remains unanswered is how to quantify infection in this age group to inform treatment strategies. The aim of this study was thus to determine whether a relationship exists between levels of schistosome infection in PSAC and school-aged children (SAC), that can be used to determine unknown schistosome infection prevalence levels in PSAC. A systematic search of publications reporting schistosomiasis prevalence in African PSAC and SAC was conducted. The search strategy was formulated using the PRISMA guidelines and SPIDER search strategy tool. The published data was subjected to regression analysis to determine if a relationship exists between infection levels in PSAC and SAC. The interaction between SAC and community treatment history was also entered in the regression model to determine if treatment history significantly affected the relationship between PSAC and SAC prevalence. The results showed that a significant positive relationship exists between infection prevalence levels in PSAC and SAC for Schistosoma mansoni (r = 0.812, df (88, 1), p = <0.0001) and S. haematobium (r = 0.786, df (53, 1), p = <0.0001). The relationship was still significant after allowing for diagnostic method, treatment history, and the African sub-region where the study was conducted (S. mansoni: F = 25.63, df (88, 9), p = <0.0001; S. haematobium: F = 10.20, df (53, 10), p = <0.0001). Using the regression equation for PSAC and SAC prevalence, over 90% of the PSAC prevalence studies were placed in the correct WHO classifications category based on the SAC levels, regardless of treatment history. The study indicated that schistosome prevalence in SAC can be extended as a proxy for infection levels in PSAC, extending on its current use in the adult population. SAC prevalence data could identify where there is a need to accelerate and facilitate the treatment of PSAC for schistosomiasis in Africa.

Preschool-aged children (PSAC), i.e. aged ≤ 6 years, are not included in preventative chemotherapy programmes, currently advocated by the WHO for the treatment of schistosomiasis. This is due to the lack of a paediatric formulation of the drug of choice, praziquantel, and the current guidelines which requires diagnosis before treatment. As the global community prepares for the deployment of a new paediatric formulation of praziquantel, there is a need to find a strategy to quantify infection in this age group. In schistosome endemic areas, infection levels in school-aged children (SAC) are already used to inform infection levels in the community. Thus, we investigated the relationship between SAC and PSAC schistosome prevalence levels within the same community, to determine if data from SAC could be used to predict infection levels in PSAC. Our results show that PSAC prevalence levels are significantly correlated with SAC prevalence levels. Our findings are applicable to communities that have received preventative chemotherapy in SAC or in SAC and adults, as well as those that have not received any. Our study indicates that it is possible to extrapolate PSAC prevalence levels from SAC prevalence, and to make a treatment decision on that basis.

Single oral fixed-dose praziquantel-miltefosine nanocombination for effective control of experimental schistosomiasis mansoni

Background

The control of schistosomiasis has been centered to date on a single drug, praziquantel, with shortcomings including treatment failure, reinfection, and emergence of drug resistance. Drug repurposing, combination therapy or nanotechnology were explored to improve antischistosomal treatment. The aim of the present study was to utilize a novel combination of the three strategies to improve the therapeutic profile of praziquantel. This was based on a fixed-dose nanocombination of praziquantel and miltefosine, an antischistosomal repurposing candidate, co-loaded at reduced doses into lipid nanocapsules, for single dose oral therapy.

Methods

Two nanocombinations were prepared to provide 250 mg praziquantel-20 mg miltefosine/kg (higher fixed-dose) or 125 mg praziquantel-10 mg miltefosine/kg (lower fixed-dose), respectively. Their antischistosomal efficacy in comparison with a non-treated control and their praziquantel or miltefosine singly loaded counterparts was assessed in murine schistosomiasis mansoni. A single oral dose of either formulation was administered on the initial day of infection, and on days 21 and 42 post-infection. Scanning electron microscopic, parasitological, and histopathological studies were used for assessment. Preclinical data were subjected to analysis of variance and Tukeyʼs post-hoc test for pairwise comparisons.

Results

Lipid nanocapsules (~ 58 nm) showed high entrapment efficiency of both drugs (> 97%). Compared to singly loaded praziquantel-lipid nanocapsules, the higher nanocombination dose showed a significant increase in antischistosomal efficacy in terms of statistically significant decrease in mean worm burden, particularly against invasive and juvenile worms, and amelioration of hepatic granulomas (P ≤ 0.05). In addition, scanning electron microscopy examination showed extensive dorsal tegumental damage with noticeable deposition of nanostructures.

Conclusions

The therapeutic profile of praziquantel could be improved by a novel multiple approach integrating drug repurposing, combination therapy and nanotechnology. Multistage activity and amelioration of liver pathology could be achieved by a new praziquantel-miltefosine fixed-dose nanocombination providing 250 mg praziquantel-20 mg miltefosine/kg. To the best of our knowledge, this is the first report of a fixed-dose nano-based combinatorial therapy for schistosomiasis mansoni. Further studies are needed to document the nanocombination safety and explore its prophylactic activity and potential to hinder the onset of resistance to the drug components.

Prevalence and risk factors of Schistosoma mansoni infection among children under two years of age in Mbita, Western Kenya

Despite growing evidence that infants and very young children can be infected with schistosomes, the epidemiological features and risk factors are not well described in this age group. We aimed to assess the prevalence of S. mansoni infection in children under two years of age from a population with a known high burden of infection in school-aged children and adults and thus inform the need for interventions in this potentially vulnerable age group. In a cross-sectional study in Mbita Sub-county, along the east coast of Lake Victoria, Western Kenya, we enrolled 361 children aged 6-23 months. The prevalence of S. mansoni infection was detected using the Kato-Katz stool examination and a point-of-care test for urinary circulating cathodic antigen (POC-CCA) (Rapid Medical Diagnostics, Pretoria, South Africa). Three-hundred and five (305) children had complete data of whom 276 (90.5%, 95%CI: 86.6-93.5) children were positive for S. mansoni by the POC-CCA test, while 11 (3.6%, 95%CI: 1.8-6.4) were positive by the Kato-Katz method. All Kato-Katz positive cases were also positive by the POC-CCA test. In multivariable analysis, only geographical area, Rusinga West (AOR = 7.1, 95%CI: 1.4-35.2, P = 0.02), was associated with S. mansoni infection using Kato-Katz test. Independent associations for POC-CCA positivity included age, (12-17 months vs 6-11 months; AOR = 7.8, 95%CI: 1.8-32.6, P = 0.002) and breastfeeding in the previous 24 hours (AOR = 3.4, 95%CI: 1.3-9.0, P = 0.009). We found a potentially very high prevalence of S. mansoni infection among children under two years of age based on POC-CCA test results in Mbita Sub-county, Kenya, which if confirmed strongly supports the need to include infants in public health strategies providing universal prophylactic treatment in high burden settings. Further research is required to determine the accuracy of diagnostic tools to detect light infection among very young children and possible long-term health impacts.

Clinical morbidity associated with Schistosoma haematobium infection in pre-school age children from an endemic district in Zimbabwe

OBJECTIVE

To investigate Schistosoma haematobium morbidity in infected pre-school age children and establish their disease burden.

METHODOLOGY

Pre-school age children (1-5 years) who were lifelong residents of the study area and had no other infections were included in the study. Participants underwent a physical examination with clinicians blinded to their infection status. Diagnosis of S. haematobium was by urine filtration.

RESULTS

The prevalence of S. haematobium was 35.1% (146/416). The clinical features observed in patients with Schistosoma haematobium were as follows: wheezes (morbidity attributable factor (AF = 93.9%), haematuria (AF = 92.6%), ascites (AF = 91.5%), atopy (AF = 76.9%), inguinal lymphadenopathy (AF = 68.4%), stunting (AF = 38.2), malnutrition (MUAC)(AF = 20%) and weight for height scales (AF = 5%). Schistosoma. haematobium infected children were at greater odds ratio of presenting with inguinal lymphadenopathy (AOR)=99.2(95% CI 24.2 to 854.5), wheezes in the chest (AOR = 35.4 95% CI 15.3 to 94.2), Distended abdomen with ascites (AOR = 23.9 95% CI 11.4 to 54), haematuria (AOR = 12.6 95% CI 11.6 to 14.1), atopy history (AOR = 5.6 95% CI 1.85 to 20.2), malnutrition (AOR = 2.3 95% CI 1.4 to 3.2) and stunting (AOR = 1.9 95% CI 1.1 to2.7).

CONCLUSION

The study is novel as it demonstrates for the first time clinical morbidity markers associated with S. haematobium infection in pre-school age children. Furthermore the study adds scientific evidence to the call for inclusion of pre-school age children in schistosomiasis control programmes. These morbidity markers highlight the need for early diagnosis and screening for S. haematobium in pre-school age children.

Efficacy and safety of single-dose 40 mg/kg oral praziquantel in the treatment of schistosomiasis in preschool-age versus school-age children: An individual participant data meta-analysis

BACKGROUND

Better knowledge of the efficacy and safety of single-dose 40 mg/kg oral praziquantel in preschool-age children is required, should preventive chemotherapy programs for schistosomiasis be expanded to include this age group.

METHODOLOGY

We analyzed individual participant-level data from 16 studies (13 single-arm or cohort studies and three randomized trials), amounting to 683 preschool-age children (aged <6 years) and 2,010 school-age children (aged 6-14 years). Children had a documented Schistosoma mansoni or S. haematobium infection, were treated with single 40 mg/kg oral praziquantel, and assessed between 21 and 60 days post-treatment. Efficacy was expressed as arithmetic mean and individual egg reduction rate (ERR) and meta-analyzed using general linear models and mixed models. Safety was summarized using reported adverse events (AEs).

PRINCIPAL FINDINGS

Preschool-age children had significantly lower baseline Schistosoma egg counts and more losses to follow-up compared to school-age children. No difference in efficacy was found between preschool- and school-age children using a general linear model of individual-participant ERR with baseline log-transformed egg count as covariate and study, age, and sex as fixed variables, and a mixed model with a random effect on the study. Safety was reported in only four studies (n = 1,128 individuals); few AEs were reported in preschool-age children 4 and 24 hours post-treatment as well as at follow-up. Three severe but not serious AEs were recorded in school-age children during follow-up.

CONCLUSIONS/SIGNIFICANCE

There is no indication that single-dose 40 mg/kg oral praziquantel would be less efficacious and less safe in preschool-age children compared to school-age children, with the caveat that only few randomized comparisons exist between the two age groups. Preventive chemotherapy might therefore be extended to preschool-age children, with proper monitoring of its efficacy and safety.

Schistosomiasis Control: Leave No Age Group Behind

Despite accelerating progress towards schistosomiasis control in sub-Saharan Africa, several age groups have been eclipsed by current treatment and monitoring strategies that mainly focus on school-aged children. As schistosomiasis poses a threat to people of all ages, unfortunate gaps exist in current treatment coverage and associated monitoring efforts, preventing subsequent health benefits to preschool-aged children as well as certain adolescents and adults. Expanding access to younger ages through the forthcoming pediatric praziquantel formulation and improving treatment coverage in older ages is essential. This should occur alongside formal inclusion of these groups in large-scale monitoring and evaluation activities. Current omission of these age groups from treatment and monitoring exacerbates health inequities and has long-term consequences for sustainable schistosomiasis control.

Sensitive diagnostic tools and targeted drug administration strategies are needed to eliminate schistosomiasis

Although preventive chemotherapy has been instrumental in reducing schistosomiasis incidence worldwide, serious challenges remain. These problems include the omission of certain groups from campaigns of mass drug administration, the existence of persistent disease hotspots, and the risk of recrudescent infections. Central to these challenges is the fact that the diagnostic tools currently used to establish the burden of infection are not sensitive enough, especially in low-endemic settings, which results in underestimation of the true prevalence of active Schistosoma spp infections. This central issue necessitates that the current schistosomiasis control strategies recommended by WHO are re-evaluated and, possibly, adapted. More targeted interventions and novel approaches have been used to estimate the prevalence of schistosomiasis, such as establishing infection burden by use of precision mapping, which provides high resolution spatial information that delineates variations in prevalence within a defined geographical area. Such information is instrumental in guiding targeted intervention campaigns. However, the need for highly accurate diagnostic tools in such strategies is a crucial factor that is often neglected. The availability of highly sensitive diagnostic tests also opens up the possibility of applying strategies of sample pooling to reduce the cost of control programmes. To interrupt the transmission of, and eventually eliminate, schistosomiasis, better local targeting of preventive chemotherapy, in combination with highly sensitive diagnostic tools, is crucial.

The gut microbiome but not the resistome is associated with urogenital schistosomiasis in preschool-aged children

Helminth parasites have been shown to have systemic effects in the host. Using shotgun metagenomic sequencing, we characterise the gut microbiome and resistome of 113 Zimbabwean preschool-aged children (1-5 years). We test the hypothesis that infection with the human helminth parasite, Schistosoma haematobium, is associated with changes in gut microbial and antimicrobial resistance gene abundance/diversity. Here, we show that bacteria phyla Bacteroidetes, Firmicutes, Proteobacteria, and fungi phyla Ascomycota, Microsporidia, Zoopagomycota dominate the microbiome. The abundance of Proteobacteria, Ascomycota, and Basidiomycota differ between schistosome-infected versus uninfected children. Specifically, infection is associated with increases in Pseudomonas, Stenotrophomonas, Derxia, Thalassospira, Aspergillus, Tricholoma, and Periglandula, with a decrease in Azospirillum. We find 262 AMR genes, from 12 functional drug classes, but no association with individual-specific data. To our knowledge, we describe a novel metagenomic dataset of Zimbabwean preschool-aged children, indicating an association between urogenital schistosome infection and changes in the gut microbiome.

Restaging Pulmonary Schistosomiasis

Schistosomiasis is traditionally classified into an acute and a chronic phase, although a precise temporal distinction between the two phases has not been established. Lung involvement can be observed in both phases. We previously reported seven cases of pulmonary lesions due to chronic schistosomiasis in African immigrants. All cases were documented with CT scans and demonstrated complete resolution after treatment with praziquantel. Moreover, another case showed spontaneous disappearance of the nodule before treatment with praziquantel. These findings are similar to those observed in the acute phase of schistosomiasis, with well-defined or ground glass nodules that resolve spontaneously. According to these findings, we postulate the presence of an "intermediate" phase of schistosomiasis involving the lungs that can be defined as an "early chronic phase," and presents analogies to the acute phase. We also hypothesize that in the "early chronic phase," the female worms transit through the lungs where they may lay eggs. These passages not only cause transient, but also radiologically visible alterations. The pathophysiology of lung lesions in the late chronic phase is probably different: the adult worms settled in the mesenteric plexuses produce eggs for years. The eggs repeatedly migrate to the perialveolar capillary beds via portal-caval shunting. Thus, in this case it is the eggs and not the adult worms that reach the lungs in a scattered way. Based on our findings, we suggest the alternative hypothesis that the pulmonary involvement is a phase of the natural evolution of the infection, both from Schistosoma mansoni and Schistosoma haematobium.

Factors associated with relevant knowledge of intestinal schistosomiasis and intention to participate in treatment campaigns: a cross sectional survey among school children at Ijinga Island on Lake Victoria, North-Western Tanzania

BACKGROUND

Annual Mass Drug Administration (MDA) using praziquantel targeting primary school children is the main control strategy against schistosomiasis in Tanzania. However, there are concerns about decreasing participation in mass drug administration among primary school children for unknown reasons. Therefore, the aim of this study was to identify factors related to relevant knowledge about schistosomiasis and the intention to participate in mass drug administration among primary school children in order to give recommendations for future projects.

METHODS

A cross sectional, extended knowledge, attitudes and practices (KAP) survey was conducted among 356 primary school children aged 5-17 years in February-March 2016 using a pre-tested questionnaire. This survey was part of a baseline assessment for an integrated proof of concept study aiming towards schistosomiasis elimination on Ijinga Island. Outcomes of interest in logistic regression analysis were relevant knowledge and high intention to participate in treatment campaigns. Explanatory variables were sociodemographic information sources and elements aligned to Protection Motivation Theory (PMT).

RESULTS

Only 17% of the children had relevant intestinal schistosomiasis related knowledge and very few of them knew any of the S. mansoni manifestations and complications. Factors associated with relevant schistosomiasis knowledge were previous diagnosis of schistosomiasis (aOR = 2.43, 95%CI: 1.1-5.6), having heard about schistosomiasis at school (aOR = 9.94, 95%CI: 5.0-19.7) and being enrolled in 6th or 7th grade (aOR = 3.94, 95%CI: 1.3-11.8). Only 40% of the children demonstrated high intention to participate in treatment campaigns. Factors associated with high intention to participate in MDA were previous diagnosis (aOR = 2.23, 95%CI: 1.1-4.7), perceived general risk of disease transmission by lake water (aOR = 1.79, 95%CI: 1.0-3.1), perceived own vulnerability of getting infected (aOR = 5.10, 95%CI: 2.1-12.6), perceived danger of the disease (aOR = 2.47, 95%CI: 1.3-4.8) and the perceived effectiveness of medicaments to cure the disease (aOR = 2.86, 95%CI: 1.4-5.7).

CONCLUSIONS

The minority of the school children had high level of theoretical knowledge about schistosomiasis and a small proportion of the children demonstrated high intention to participate in mass drug administration. In general, practical knowledge on preventive measures such as taking anti-schistosomiasis drug during MDA need to be impacted in school children to increase their participation in the control program.

Intestinal schistosomiasis of Ijinga Island, north-western Tanzania: prevalence, intensity of infection, hepatosplenic morbidities and their associated factors

Background

Intestinal schistosomiasis is highly endemic in Tanzania and mass drug administration (MDA) using praziquantel is the mainstay of the control program. However, the MDA program covers only school aged children and does not include neither adult individuals nor other public health measures. The Ijinga schistosomiasis project examines the impact of an intensified treatment protocol with praziquantel MDA in combination with additional public health interventions. It aims to investigate the feasibility of eliminating intestinal schistosomiasis in a highly endemic African setting using an integrated community-based approach. In preparation of this project, we report about baseline data on S.mansoni prevalence, intensity of infection, related hepatosplenic morbidities and their associated factors.

Methods

A cross sectional study was conducted among 930 individuals aged 1–95 years living at Ijinga Island, north-western Tanzania in September 2016. Single stool and urine samples were collected from each study participant and processed using Kato Katz (KK) technique and point-of-care Circulating Cathodic (POC-CCA) antigen test for detection of S.mansoni eggs and antigen respectively. Ultrasonographical examination for S.mansoni hepatosplenic morbidities was done to all participants. For statistical analyses Fisher’s exact test, chi-square test, student-t-test, ANOVA and linear regression were used where applicable.

Results

Overall based on KK technique and POC-CCA test, 68.9% (95%CI: 65.8–71.8) and 94.5% (95%CI: 92.8–95.8) were infected with S.mansoni. The overall geometrical mean eggs per gram (GMepg) of faeces was 85.7epg (95%CI: 77.5–94.8). A total of 27.1, 31.2 and 51.9% of the study participants had periportal fibrosis (PPF-grade C-F), splenomegaly and hepatomegaly. Risk factors for PPF were being male (aRR = 1.08, 95%CI: 1.02–1.16, P < 0.01), belong to the age group 16–25 years (aRR = 1.23, 95%CI: 105–1.44, P < 0.01), 26–35 years (aRR = 1.42, 95%CI: 1.21–1.67, P < 0.001), 36–45 years (aRR = 1.56, 95%CI:1.31–1.84, P < 0.001) and ≥ 46 years (aRR = 1.64, 95%CI:1.41–1.92, P < 0.001). The length of the left liver lobe was associated with being female (P < 0.03), belong to the age group 1–5 years (P < 0.013), 6–15 years (P < 0.04) and S.mansoni intensity of infection (P < 0.034). Male sex (aRR = 1.15, 95%CI:1.06–1.24, P < 0.001) and belonging to the age groups 16–25 years (aRR = 1.27, 95%CI:1.05–1.54, P < 0.02) or 26–35 years (aRR = 1.32, 95%CI:108–1.61, P < 0.01) were associated with splenomegaly.

Conclusion

Schistosoma mansoni infection and its related morbidities (hepatomegaly, splenomegaly, periportal fibrosis) are common in the study area. Age, sex and intensity of infection were associated with periportal fibrosis. The prevalence of S.mansoni was above 50% in each age group and based on the observed prevalence, we recommend MDA to the entire community.