Efficacy and safety of praziquantel in preschool-aged and school-aged children infected with Schistosoma mansoni: a randomised controlled, parallel-group, dose-ranging, phase 2 trial

Schistosomiasis in migrant children and adolescents in a paediatric tropical referral unit in Spain: diagnosis and long-term management challenges

Globalisation and population movement have led to an increasing number of migrant children residing in areas non-endemic for schistosomiasis. However, diagnosing and managing schistosomiasis in children remain controversial. This study aims to investigate the prevalence of schistosomiasis in migrant children and to describe the diagnostic approach and management strategies, including long-term follow-up, to explore the potential role of serological tests in evaluating treatment response. We conducted a retrospective descriptive study spanning from January 2014-July 2021 at a referral unit for Paediatric Tropical Diseases in Madrid (Spain). The study included patients under 18 years diagnosed with schistosomiasis. Of 679 children screened for schistosomiasis, 73 (10.8%) tested positive. The median age was 16.3 years [IQR 9-17.6], 74% male. The majority originated from Sub-Saharan Africa (47%) and Asia (47%). Only 40% presented with symptoms, with gastrointestinal (18%) and cutaneous (17%) manifestations being the most common. Eosinophilia was observed in 43% (median [IQR]: 1103/mm3 [671-1536]), and ova were visualised in the urine of 2/50 (4.0%). Praziquantel treatment was administered to 92%, and 5 patients required retreatment. Follow-up data were available for 58 (80%) over a median period of 9 months [IQR 6-19.8], revealing a progressive decline in eosinophil count, IgE titres, and ELISA optical density.    Conclusion: In this series, the prevalence of schistosomiasis among migrant children was significant (10%), highlighting the importance of including serological tests in migrant health screening. The disease is largely asymptomatic, eosinophilia is often absent, and visualisation of ova in urine is exceedingly rare. Eosinophil count, IgE titres, and ELISA optical density could prove valuable as an initial approach for monitoring inflammation during follow-up assessments. What is Known: • The burden of disease related to schistosomiasis is significant, particulary in children, and it is advisable to screen this vulnerable population. What is New: • Eosinophilia may not be present in parasitic infections, so serological tests are crucial for screening migrant children. • Serological monitoring facilitates long-term management of migrant children with schistosomiasis.

Efficacy and safety of praziquantel treatment against Schistosoma mansoni infection among pre-school age children in southern Ethiopia

BACKGROUND

Preventive chemotherapy with a single dose of praziquantel given to an all-at-risk population through mass drug administration is the cornerstone intervention to control and eliminate schistosomiasis as a public health problem. This intervention mainly targets school age children, and pre-school age children (pre-SAC) are excluded from receiving preventive chemotherapy, partly due to scarcity of data on praziquantel treatment outcomes.

METHODS

We conducted active efficacy and safety surveillance of praziquantel treatment among 240 Schistosoma mansoni-infected pre-SAC who received a single dose of praziquantel (40 mg/kg) in southern Ethiopia. The study outcomes were egg reduction rates (ERR) and cure rates (CRs) four weeks after treatment using the Kato-Katz technique and treatment-associated adverse events (AEs) that occurred within 8 days post-treatment.

RESULTS

The overall ERR was 93.3% (WHO reference threshold ≥ 90%), while the CR was 85.2% (95% CI = 80.0-89.5%). Baseline S. mansoni infection intensity was significantly associated with CRs, 100% among light infected than moderate (83.4%) or heavy (29.4%) infected children. An increase of 100 in baseline S. mansoni egg count per gram of stool resulted in a 26% (95% CI: 17%, 34%) reduction in the odds of cure. The incidence of experiencing at least one type of AE was 23.1% (95% CI: 18.0%, 29.0%). Stomachache, diarrhea, and nausea were the most common AEs. AEs were mild-to-moderate grade and transient. Pre-treatment moderate (ARR = 3.2, 95% CI: 1.69, 6.14) or heavy infection intensity (ARR = 6.5, 95% CI: 3.62, 11.52) was a significant predictor of AEs (p < 0.001). Sex, age, or soil-transmitted helminth coinfections were not significant predictors of CR or AEs.

CONCLUSIONS

Single-dose praziquantel is tolerable and effective against S. mansoni infection among pre-SAC, and associated AEs are mostly mild-to-moderate and transient. However, the reduced CR in heavily infected and AEs in one-fourth of S. mansoni-infected pre-SAC underscores the need for safety and efficacy monitoring, especially in moderate-to-high infection settings. Integrating pre-SACs in the national deworming programs is recommended to accelerate the elimination of schistosomiasis as a public health problem.

Provider and User Acceptability of Integrated Treatment for the Control of Malaria and Helminths in Saraya, South-Eastern Senegal

Integration of vertical programs for the control of malaria, schistosomiasis, and soil-transmitted helminthiasis has been recommended to achieve elimination of malaria and neglected tropical diseases (NTD) by 2030. This qualitative study was conducted within the context of a randomized controlled trial to explore the perceptions and views of parents/caregivers of at-risk children and healthcare providers to determine their acceptability of the integrated malaria-helminth treatment approach. Randomly selected parents/caregivers of children enrolled in the trial, healthcare providers, trial staff, malaria, and NTD program managers were interviewed using purpose-designed topic guides. Transcripts obtained from the interviews were coded and common themes identified using content analysis were triangulated. Fifty-seven study participants comprising 26 parents/caregivers, 10 study children aged ≥ 10 years, 15 trial staff, four healthcare providers, and two managers from the Senegal Ministry of Health were interviewed. Thirty-eight of the participants (66.7%) were males, and their ages ranged from 10 to 65 years. Overall, the integrated malaria-helminth treatment approach was considered acceptable, but the study participants expressed concerns about the taste, smell, and side effects associated with amodiaquine and praziquantel in the combination package. Reluctance to accept the medications was also observed among children aged 10 to 14 years due to peer influence and gender-sensitive cultural beliefs. Addressing concerns about the taste and smell of amodiaquine and praziquantel is needed to optimize the uptake of the integrated treatment program. Also, culturally appropriate strategies need to be put in place to cater for the inclusion of children aged 10 to 14 years in this approach.

Efficacy of Single-Dose Praziquantel for the Treatment of Schistosoma mansoni Infections among School Children in Rwanda

Preventive chemotherapy with single-dose praziquantel is the WHO-recommended intervention strategy to eliminate schistosomiasis as a public health problem in endemic countries. Surveillance of drugs used in mass drug administration (MDA) programs is recommended to evaluate its effectiveness in reducing transmissions. After a decade-long implementation of a school-based MDA program in Rwanda, we conducted efficacy surveillance of single-dose praziquantel MDA against S. mansoni infection. Two weeks before MDA, stool examinations were performed to screen MDA-eligible school children (n = 4998) for S. mansoni infection using the Kato-Katz technique, and 265 (6.5%) children tested positive for the infection. All children received praziquantel and albendazole as preventive chemotherapy through the MDA campaign. Infected children were enrolled and followed for efficacy monitoring, and stool examination was repeated after three weeks post-MDA (n = 188). Before treatment, 173 (92%) had a light infection, and 15 (8%) had a moderate infection intensity. The primary and secondary outcomes were parasitological cure and egg reduction rates at three weeks post-treatment. The overall cure and egg reduction rates for S. mansoni infection were 97.9% (95% CI = 94.6-99.4) and 97.02%, respectively. Among the 173 children with light infection intensity, 170 (98.3%, 95% CI = 95.0-99.6) were cured, and among the 15 children who had moderate infection intensity, 14 (93.3%) were cured. No significant association between cure rate and pre-treatment infection intensity was observed. We conclude that single-dose praziquantel is efficacious against light-to-moderate S. mansoni infection. Preventive chemotherapy with praziquantel effectively reduces schistosome reservoirs and transmission among school-age children.

The Existing Drug Nifuroxazide as an Antischistosomal Agent: In Vitro, In Vivo, and In Silico Studies of Macromolecular Targets

Schistosomiasis is a parasitic disease that afflicts approximately 250 million people worldwide. There is an urgent demand for new antiparasitic agents because praziquantel, the only drug available for the treatment of schistosomiasis, is not universally effective and may derail current progress toward the WHO goal of eliminating this disease as a public health problem by 2030. Nifuroxazide (NFZ), an oral nitrofuran antibiotic, has recently been explored to be repurposed for parasitic diseases. Here, in vitro, in vivo, and in silico studies were conducted to evaluate the activity of NFZ on Schistosoma mansoni. The in vitro study showed significant antiparasitic activity, with 50% effective concentration (EC50) and 90% effective concentration (EC90) values of 8.2 to 10.8 and 13.7 to 19.3 μM, respectively. NFZ also affected worm pairing and egg production and induced severe damage to the tegument of schistosomes. In vivo, a single oral dose of NFZ (400 mg/kg of body weight) to mice harboring either prepatent or patent S. mansoni infection significantly reduced the total worm burden (~40%). In patent infection, NFZ achieved a high reduction in the number of eggs (~80%), but the drug caused a low reduction in the egg burden of animals with prepatent infection. Finally, results from in silico target fishing methods predicted that serine/threonine kinases could be one of the potential targets for NFZ in S. mansoni. Overall, the present study revealed that NFZ possesses antischistosomal properties, mainly in terms of egg burden reduction in animals with patent S. mansoni infection. IMPORTANCE The increasing recognition of the burden imposed by helminthiasis, associated with the limited therapeutic arsenal, has led to initiatives and strategies to research and develop new drugs for the treatment of schistosomiasis. One of these strategies is drug repurposing, which considers low-risk compounds with potentially reduced costs and shorter time for development. In this study, nifuroxazide (NFZ) was evaluated for its anti-Schistosoma mansoni potential through in vitro, in vivo, and in silico studies. In vitro, NFZ affected worm pairing and egg production and induced severe damage to the tegument of schistosomes. In vivo, a single oral dose of NFZ (400 mg/kg) to mice harboring either prepatent or patent S. mansoni infection significantly reduced the total worm burden and egg production. In silico investigations have identified serine/threonine kinases as a molecular target for NFZ. Collectively, these results implied that NFZ might be a potential therapeutic candidate for the treatment of schistosomiasis.

Efficacy, safety, and palatability of arpraziquantel (L-praziquantel) orodispersible tablets in children aged 3 months to 6 years infected with Schistosoma in Côte d'Ivoire and Kenya: an open-label, partly randomised, phase 3 trial

BACKGROUND

WHO has underlined the need for a child-friendly treatment for schistosomiasis, a prevalent parasitic disease in low-income and middle-income countries. After successful phase 1 and 2 trials, we aimed to evaluate the efficacy, safety, palatability, and pharmacokinetics of arpraziquantel (L-praziquantel) orodispersible tablets for preschool-aged children.

METHODS

This open-label, partly randomised, phase 3 study was conducted at two hospitals in Côte d'Ivoire and Kenya. Children with a minimum bodyweight of 5 kg in those aged 3 months to 2 years and 8 kg in those aged 2-6 years were eligible. In cohort 1, participants aged 4-6 years infected with Schistosoma mansoni were randomly assigned (2:1) to receive a single dose of oral arpraziquantel 50 mg/kg (cohort 1a) or oral praziquantel 40 mg/kg (cohort 1b) using a computer-generated randomisation list. Cohorts 2 (aged 2-3 years) and 3 (aged 3 months to 2 years) infected with S mansoni, and the first 30 participants in cohort 4a (aged 3 months to 6 years) infected with Schistosoma haematobium, received a single dose of oral arpraziquantel 50 mg/kg. After follow-up assessments, arpraziquantel was increased to 60 mg/kg (cohort 4b). Laboratory personnel were masked to the treatment group, screening, and baseline values. S mansoni was detected using a point-of-care circulating cathodic antigen urine cassette test and confirmed using the Kato-Katz method. The primary efficacy endpoint was clinical cure rate at 17-21 days after treatment in cohorts 1a and 1b, measured in the modified intention-to-treat population and calculated using the Clopper-Pearson method. This study is registered with ClinicalTrials.gov, NCT03845140.

FINDINGS

Between Sept 2, 2019, and Aug 7, 2021, 2663 participants were prescreened and 326 were diagnosed with S mansoni or S haematobium. 288 were enrolled (n=100 in cohort 1a, n=50 in cohort 1b, n=30 in cohort 2, n=18 in cohort 3, n=30 in cohort 4a, and n=60 in cohort 4b), but eight participants received antimalarial drugs and were excluded from the efficacy analyses. The median age was 5·1 years (IQR 4·1-6·0) and 132 (47%) of 280 participants were female and 148 (53%) were male. Cure rates with arpraziquantel were similar to those with praziquantel (87·8% [95% CI 79·6-93·5] in cohort 1a vs 81·3% [67·4-91·1] in cohort 1b). No safety concerns were identified during the study. The most common drug-related treatment-emergent adverse events were abdominal pain (41 [14%] of 288 participants), diarrhoea (27 [9%]), vomiting (16 [6%]), and somnolence (21 [7%]).

INTERPRETATION

Arpraziquantel, a first-line orodispersible tablet, showed high efficacy and favourable safety in preschool-aged children with schistosomiasis.

FUNDING

The Global Health Innovative Technology Fund, the European and Developing Countries Clinical Trials Partnership, and the healthcare business of Merck KGaA, Darmstadt, Germany (CrossRef Funder ID: 10.13039/100009945).

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.

Safety of Praziquantel and Albendazole Coadministration for the Control and Elimination of Schistosomiasis and Soil-Transmitted Helminths Among Children in Rwanda: An Active Surveillance Study

Introduction

School-based preventive chemotherapy (Deworming) with praziquantel and albendazole to control and eliminate schistosomiasis and soil-transmitted helminths as public health problems is recommended by the World Health Organization (WHO). Safety monitoring during mass drug administration (MDA) is imperative but data from sub-Saharan Africa are scarce.

Objective

The aim of this active safety surveillance study was to identify the incidence, type, severity, and risk factors for adverse events (AEs) following mass administration of praziquantel and albendazole.

Methods

Overall, 8037 school children aged 5–15 years in Rwanda were enrolled. Baseline sociodemographic, medical history and any pre-existing clinical symptoms were recorded. Participants received a single dose of praziquantel and albendazole during MDA. AEs were actively monitored on days 1, 2, and 7 post MDA.

Results

Overall, 3196 AEs were reported by 1658 children; 91.3%, 8.4%, and 0.3% of the AEs were mild, moderate, and severe, respectively, and most resolved within 3 days. Headache (21%), dizziness or fainting (15.2 %), nausea (12.8%) and stomach pain (12.2%) were the most common AEs. The overall cumulative incidence of experiencing at least one type of AE was 20.6% (95% confidence interval [CI] 19.7–21.5%), being significantly higher (p < 0.001) in children with pre-MDA clinical events (27.5%, 95% CI 25.4–29.6%) than those without (18.7%, 95% CI 17.7–19.7%). Females, older age, having pre-MDA events, types of food taken before MDA and taking two or more praziquantel tablets were significant predictors of AEs.

Conclusions

Praziquantel and albendazole MDA is safe and well-tolerated; however, one in five children experience transient mild to moderate, and in few cases severe, AEs. The incidence of AEs varies significantly between sex and age groups. Pharmacovigilance in the MDA program is recommended for timely detection and management of AEs.

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.

The economic impact of schistosomiasis

BACKGROUND

The economic impact of schistosomiasis and the underlying tradeoffs between water resources development and public health concerns have yet to be quantified. Schistosomiasis exerts large health, social and financial burdens on infected individuals and households. While irrigation schemes are one of the most important policy responses designed to reduce poverty, particularly in sub-Saharan Africa, they facilitate the propagation of schistosomiasis and other diseases.

METHODS

We estimate the economic impact of schistosomiasis in Burkina Faso via its effect on agricultural production. We create an original dataset that combines detailed household and agricultural surveys with high-resolution geo-statistical disease maps. We develop new methods that use the densities of the intermediate host snails of schistosomiasis as instrumental variables together with panel, spatial and machine learning techniques.

RESULTS

We estimate that the elimination of schistosomiasis in Burkina Faso would increase average crop yields by around 7%, rising to 32% for high infection clusters. Keeping schistosomiasis unchecked, in turn, would correspond to a loss of gross domestic product of approximately 0.8%. We identify the disease burden as a shock to the agricultural productivity of farmers. The poorest households engaged in subsistence agriculture bear a far heavier disease burden than their wealthier counterparts, experiencing an average yield loss due to schistosomiasis of between 32 and 45%. We show that the returns to water resources development are substantially reduced once its health effects are taken into account: villages in proximity of large-scale dams suffer an average yield loss of around 20%, and this burden decreases as distance between dams and villages increases.

CONCLUSIONS

This study provides a rigorous estimation of how schistosomiasis affects agricultural production and how it is both a driver and a consequence of poverty. It further quantifies the tradeoff between the economics of water infrastructures and their impact on public health. Although we focus on Burkina Faso, our approach can be applied to any country in which schistosomiasis is endemic.

Risk Factors and Spatial Distribution of Schistosoma mansoni Infection among Preschool-Aged Children in Blapleu, Biankouma District, Western Côte d'Ivoire

Schistosoma mansoni infection is common among school-age children (SAC) in western Côte d'Ivoire. Little is known on the infection rate of preschool-aged children (PSAC) due to epidemiological data deficiency and nonappropriate formulation of the drug. Thus, mass drug administration for schistosomiasis control mainly targets SAC. This study aims to identify the risk factors and spatial distribution of S. mansoni infection among PSAC in Blapleu, endemic foci of S. mansoni. We carried out a cross-sectional study in households with PSAC aged 1–6 years. A structured questionnaire was administered to mothers/guardians to obtain data on sociodemographics and water contact behaviour of children. Point-of-care circulating cathodic antigen (POC-CCA) immunodiagnostic test in urine and Kato-Katz (K-K) method with stool were used for S. mansoni infection diagnosis. Multiple logistic regression analysis was performed to determine the relationship between S. mansoni infection and sociodemographic data. Coordinates recorded by a Global Positioning System of households, water source points, and infected PSAC were used to map the spatial distribution of S. mansoni infection cases. This study was conducted with 350 PSAC aged 1–6 years. The overall infection prevalence of S. mansoni varies from 31.43% with the K-K method to 62.86% with the POC-CCA. PSAC aged 2–6 years were highly infected with S. mansoni than those aged 1-2 years (OR = 14.24, 95% CI: 5.85–34.64). PSAC who did not have access and who do not live close to the infected water source were at a significant lower risk of S. mansoni infection (OR = 0.13, 95% CI: 0.057–0.30). The main purpose of water contact of PSAC was to help their mother for laundry that occurs weekly. In Blapleu, a high risk of S. mansoni infection was observed among PSAC. Schistosomiasis control effort in such localities should include information, education, and communication, water, sanitation, and hygiene, and particularly chemotherapy targeting PSAC, reinforcing the need of the paediatric praziquantel formulation.

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.

Optimal single sampling time-point for monitoring of praziquantel exposure in children

Praziquantel pharmacokinetics studies in schistosomiasis infected children are scarce partly due to the challenges/complexity of intensive blood sampling in the target population. This study was aimed to investigate the optimal single sampling time-point for monitoring praziquantel exposure. This was intensive pharmacokinetic study conducted among 32 Schistosoma mansoni infected children treated with an oral standard single-dose 40 mg/kg praziquantel. Plasma samples were collected at 0, 1, 2, 4, 6 and 8 h post-praziquantel administration. Quantification of praziquantel and its enantiomers (R- and S-praziquantel) concentrations was done by Liquid chromatography-tandem mass spectrometer (LC-MS/MS). The correlation between area under the plasma concentration-time curve from 0 to 8 h (AUC₈) and plasma concentrations at each specific sampling time-point was determined by Pearson's correlation coefficient (r²). The median age (range) of the study population was 12.5 years (10-17). The study participants were 17 males and 15 females. Both total praziquantel and its enantiomers (R- and S-praziquantel) displayed a wide inter-individual pharmacokinetic variability. Regression analysis indicated that, plasma concentrations collected at 4 h post-dose had a significantly highest correlation with the AUC₈ for both total praziquantel (r² = 0.81, p < 0.001) and S-praziquantel (r² = 0.84, p < 0.001) than any other sampling time-point; while for R-praziquantel, plasma concentrations collected at 6 h sampling time-point had a significantly highest correlation with the AUC₈ (r² = 0.79, p < 0.001) than any other sampling time-point. Four hours sampling time-point post-praziquantel administration is ideal optimal single sampling time-point for therapeutic monitoring of total praziquantel exposure while 6 h sampling time-point is suitable for monitoring of a pharmacologically active R-praziquantel enantiomer.

Influence of schistosomiasis on host vaccine responses

Schistosomiasis is a debilitating helminthiasis which commonly establishes as a chronic infection in people from endemic areas. As a potent modulator of the host immune response, the Schistosoma parasite and its associated products can directly interfere with its host's ability to mount adequate immune responses to unrelated antigens. As a result, increased attention is gathering on studies assessing the influence of helminths, particularly the causal agent of schistosomiasis, on host responsiveness to vaccines. However, to date, no consensus has been drawn regarding the influence of schistosomiasis on host vaccine responses. Here, we review available evidence on the influence of transgenerational and direct Schistosoma parasite exposure on host immune responses to unrelated vaccines. In addition, we evaluate the potential of praziquantel (PZQ) treatment in restoring schistosomiasis-impacted vaccine responses.

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.

A 12-year follow-up of intestinal schistosomiasis in pre-school-aged children in Assoni Village, Eastern Senegal

Background

To monitor the prevalence of schistosomiasis in school-aged children (SAC), the National Bilharzia Control Program (PNLB) was set up by the Senegalese authorities; however, geographically isolated Bedik ethnic groups that did not benefit from this program were found to be heavily infected with Schistosoma mansoni. This observation led us to implement a new schistosomiasis control program in 2008 under the aegis of the non-governmental organization “Le Kaïcedrat” and in partnership with the PNLB/WHO to monitor the prevalence of schistosomiasis in this area. In the village of Assoni, where 100% of SAC were infected, analysis of the stools of pre-school-aged children (PSAC) showed that they were massively infected, so we decided to focus our program on them.

Methods

From 2008 to 2020, we (i) monitored the prevalence of S. mansoni in PSAC in Assoni using double-stool smear preparation, (ii) treated the infected PSAC with a standard dose of praziquantel 40 mg/kg, (iii) ran educational campaigns each year in the village, and (iv) built latrines to improve sanitation and reduce schistosomiasis transmission. Linear regression was used to examine the trend in the annual schistosomiasis prevalence and a two-sided of Chi-squared test was used to compare prevalence between the different age groups of PSAC.

Results

We observed an extremely high prevalence of schistosomiasis (78%) in PSAC before implementation of the program in 2008. Contamination occurred in very young children, as 64.3% of children under 2 years old were infected. Moreover, prevalence increased with age and reached 96.8% in children 4 to < 6 years old. Our annual interventions in Assoni Village raised awareness among villagers that water bodies were areas of significant infestation, allowed the building of 88 latrines and led to a decrease in prevalence in PSAC as only 11% of these children were infected in 2020.

Conclusion

Our study allowed Assoni to be the first village in Senegal to treat PSAC since 2014, but only on an individual basis. It also shows that schistosomiasis is difficult to eradicate and that multi-sectorial actions are required to keep its prevalence at a low level.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s40249-021-00867-8.

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.

Effect of Dihydroartemisinin-Piperaquine on the Pharmacokinetics of Praziquantel for Treatment of Schistosoma mansoni Infection

Praziquantel (PZQ) and dihydroartemisinin-piperaquine (DHP) combination recently showed superior effectiveness than PZQ alone to treat intestinal schistosomiasis. In this follow-up study, we investigated the effect of DHP co-administration on the pharmacokinetics of PZQ and its enantiomers among 64 Schistosoma mansoni infected children treated with PZQ alone (n = 32) or PZQ + DHP combination (n = 32). Plasma samples collected at 0, 1, 2, 4, 6, and 8 h post-dose were quantified using UPLCMS/MS. The geometric mean (GM) of AUCs for total PZQ, R-PZQ and S-PZQ were significantly higher among children who received PZQ + DHP than PZQ alone. The geometric mean ratio (GMR) and (90% CI) of AUC_0–∞ for PZQ + DHP to PZQ for total PZQ, R-PZQ, and S-PZQ were 2.18 (1.27, 3.76), 3.98 (2.27, 7.0) and 1.86 (1.06, 3.28), respectively. The GMR and (90% CI) of AUC_0–8 for total PZQ, R-PZQ, and S-PZQ were 1.73 (1.12, 2.69), 2.94 (1.75, 4.92), and 1.50 (0.97, 2.31), respectively. The GM of C_max for total PZQ, R-PZQ and S-PZQ were significantly higher among those who received PZQ + DHP than PZQ alone. The GMR (90% CI) of C_max of PZQ + DHP to PZQ for total PZQ, R-PZQ, and S-PZQ were 1.75 (1.15, 2.65), 3.08 (1.91, 4.96), and 1.50 (1.0, 2.25%), respectively. The 90% CI of the GMRs for both AUCs and C_max for total PZQ, R-PZQ, and S-PZQ were outside the acceptable 0.80–1.25 range, indicating that the two treatment arms were not bioequivalent. DHP co-administration significantly increases systemic PZQ exposure, and this may contribute to increased effectiveness of PZQ + DHP combination therapy than PZQ alone to treat schistosomiasis.

Efficacy and Safety of Ascending Dosages of Moxidectin and Moxidectin-albendazole Against Trichuris trichiura in Adolescents: A Randomized Controlled Trial

BACKGROUND

Preventive chemotherapy is the main strategy to control soil-transmitted helminth (STH) infections. Albendazole and mebendazole are ubiquitously used, but they are not sufficiently effective against Trichuris trichiura. Moxidectin might be a useful addition to the small drug armamentarium. However, the optimal dosage of moxidectin alone and in combination with albendazole against T. trichiura and other STHs has not yet been determined.

METHODS

A Phase II, randomized, placebo-controlled, dose-finding trial was conducted in 2 secondary schools on Pemba Island, Tanzania. Using a computer-generated list, T. trichiura-infected adolescents were randomly assigned to 7 treatment arms: 8, 16, or 24 mg of moxidectin monotherapy; 8, 16, or 24 mg of moxidectin plus 400 mg of albendazole combination therapy; or placebo. The primary outcome was cure rate (CR) against T. trichiura, analyzed 13 to 20 days after treatment by quadruple Kato-Katz thick smears.

RESULTS

A total of 290 adolescents were enrolled (41 or 42 per arm). CRs against T. trichiura were 43, 46, and 44% for 8, 16, and 24 mg of moxidectin alone, respectively; 60, 62, and 66% for the same moxidectin dosages plus 400 mg of albendazole, respectively; and 12% for placebo. The moxidectin-albendazole arms also revealed higher CRs and egg reduction rates against hookworm than the monotherapy arms. Moxidectin and its combination with albendazole were well tolerated.

CONCLUSIONS

Moxidectin-albendazole is superior to moxidectin. There is no benefit of using doses above 8 mg, which is the recommended dose for onchocerciasis. The moxidectin-albendazole combination of 8 mg plus 400 mg should be investigated further to develop recommendations for appropriate control of STH infections.

CLINICAL TRIALS REGISTRATION

NCT03501251.

The Neglected Cestode Infection: Epidemiology of Hymenolepis Nana Infection Among Children in Rural Yemen

Hymenolepis nana is the most common cestode reported in humans worldwide. It is prevalent among children in the tropics and subtropics, particularly in rural poor communities where sanitation is inadequate or lacking. This cross-sectional study aims to determine the prevalence and significant risk factors of H. nana infection among children in rural Yemen. Faecal samples were collected from 498 children and screened for intestinal parasites by using wet mount, formalin-ether concentration and Kato–Katz techniques. A pretested questionnaire was used to collect demographic, socioeconomic, housing condition, and personal hygiene information. Overall, 77.5 % (386/498) of the children were found to be infected by at least one intestinal parasite species. The overall prevalence of H. nana was 17.5 % (87/498). Multivariate analysis confirmed that an age of < 6 years (adjusted odds ratio [AOR] = 4.28; 95 % (confidence interval [CI] = 2.04, 8.98), presence of other family members infected with H. nana (AOR = 2.48; 95 % CI = 1.45, 4.24), living in the highlands (AOR = 2.87; 95 % CI = 1.56, 5.26), living in a house without improved toilet facilities (AOR = 2.19; 95 % CI = 1.23, 3.88), not washing vegetables before consumption (AOR = 2.11; 95 % CI = 1.06, 4.19), and not washing hands after defecation (AOR = 1.88; 95 % CI = 1.08, 3.27) were the key factors significantly associated with H. nana infection among the studied children. In conclusion, H. nana is prevalent among children in rural Yemen, particularly among preschool-aged children. Thus, an integrated and effective programme to control intestinal parasitic infections should include preschool-aged children. Such a programme should focus on providing health education on hygienic practices, providing adequate sanitation and improved sources of drinking water, and screening and treating other infected family members.

Effect of intensive versus standard anthelminthic treatment on growth and cognition among children living in a high Schistosoma mansoni transmission setting: a study nested within a cluster-randomised trial

Background: Schistosomiasis and other worm infections have been associated with growth and cognitive impairments; however, whether treatment reverses these effects is uncertain. Moreover, mechanisms linking these infections to cognition are not clear. We aimed to compare growth and cognitive benefits of intensive versus standard anthelminthic treatment in school-aged-children and explore processes that might be involved. We hypothesised that intensive treatment would have greater benefits than standard treatment. Methods: The study was nested within a cluster-randomised trial of either quarterly single-dose praziquantel of 40mg/kg to treat Schistosoma mansoni plus triple dose albendazole of 400mg (intensive treatment) to treat soil-transmitted worms including Ascaris lumbricoides, hookworm and Trichuris trichiura, or annual single-dose praziquantel 40mg/kg plus six-monthly single-dose albendazole 400mg (standard treatment) conducted in the Koome islands in Lake Victoria, Uganda (ISRCTN47196031). Children aged 5-9 years (N=384) were assessed on primary outcomes (height, weight and eight measures of cognitive ability), worm infection, and proposed mediators of worm effects (cytokines, iron status, physical activity) at one year (intensive n=85; standard n=64) and at two years (intensive n=158; standard n=128) of the intervention. Linear regression was used to examine intervention effects on height, weight and cognitive performance. Linear mixed effects models were used to study changes in growth and cognitive performance between the two arms across the two time-points. Results: Intensive treatment resulted in lower Schistosoma mansoni prevalence than standard treatment (at one year, 41% versus 70%; adjusted odds ratio (aOR)=0.24, 95% CI: 0.12, 0.49; at two years, 39% versus 69%; aOR=0.27; 95% CI: 0.16, 0.43) but there were no significant differences in growth and cognitive outcomes at either time-point. Worms and treatment showed no consistent association with the proposed mediators of worm effects. Conclusion: Reduction in worm burden may not improve growth and cognitive outcomes in high S. mansoni transmission settings. Possible implications are discussed.

Anthelminthic treatment receipt and its predictors in Lake Victoria fishing communities, Uganda: Intervention coverage results from the LaVIISWA cluster randomised trial

BACKGROUND

Mass drug administration (MDA) is a cornerstone of control of parasitic helminths. In schistosomiasis-endemic areas with >50% of school-aged children infected, community-wide MDA with praziquantel is recommended by the World Health Organisation (WHO), with target coverage of >75%. Using data from a cluster-randomised trial of MDA treatment strategies, we aimed to describe the proportion of eligible residents who received MDA and predictors of treatment receipt, and to assess associations with helminth prevalence.

METHODS

In the Koome islands of Lake Victoria, Uganda, where baseline schistosomiasis prevalence (by single stool sample, Kato Katz) was 52% overall (all ages) and 67% among school-aged children, we conducted a cluster-randomised trial of community-wide, intensive MDA (quarterly single-dose praziquantel 40mg/kg; triple-dose albendazole 400mg) versus standard, Uganda government intervention (annual single-dose praziquantel 40mg/kg; 6-monthly single-dose albendazole). Twenty-six fishing villages were randomised, 13 per trial arm, for four years. At each treatment round, praziquantel treatment and the first dose of albendazole treatment were directly observed by the study team, registers of village residents were updated and the proportion receiving treatment among those eligible recorded.

RESULTS

During the four-year MDA, at each treatment round an average of 13,382 people were registered in the 26 villages (7,153 and 6,229 in standard and intensive intervention villages, respectively). Overall, the proportion of those eligible receiving praziquantel was lower than for albendazole (60% versus 65%), particularly in the standard arm (61% versus 71%) compared to the intensive arm (60% versus 62%). Albendazole receipt was lower when given concurrently with praziquantel. Absence was the commonest reason for non-receipt of treatment (81% albendazole, 77% praziquantel), followed by refusal (14% albendazole, 18% praziquantel). Proportions receiving treatment were lowest among school-aged children, but did not differ by sex. Longitudinal analysis of a subgroup of residents who did not move during the study period found that persistent non-receipt of treatment in this subgroup was rare. Refusal to receive treatment was highest among adults and more common among females.

CONCLUSION

In schistosomiasis high-risk communities, a combination of approaches to increasing treatment coverage, such as extended periods of treatment delivery, and the provision of incentives, may be required to achieve WHO targets.

Efficacy and Safety of Ascending Dosages of Tribendimidine Against Hookworm Infections in Children: A Randomized Controlled Trial

BACKGROUND

The global strategy to control soil-transmitted helminthiasis is mainly focused on preventive chemotherapy with albendazole and mebendazole. We assessed the efficacy and safety of ascending tribendimidine doses against hookworm infections in African school-aged children, key information for the development of tribendimidine.

METHODS

We performed a single blind, randomized, controlled trial in Côte d'Ivoire between June and August 2017. Eligible participants were randomly assigned to placebo, 100, 200, or 400 mg tribendimidine. Cure rates (CRs, primary outcome) and egg reduction rates (ERRs) were determined 14-21 days after treatment. Clinical symptoms were assessed before treatment and adverse events monitored 3 and 24 hours posttreatment.

RESULTS

CRs calculated for 130 children dose-dependently increased. The observed CRs were 20.6% (7/34), 21.2% (7/33), 38.7% (12/31), and 53.1% (17/32) for placebo, 100, 200, and 400 mg of tribendimidine, respectively. The Emax model predicted a placebo corrected net effect of 34.3 percentage points (95% confidence interval [CI], 13.3-54.4) for the 400-mg tribendimidine dose. The ERRs (geometric mean) were 30.6% (95% CI, -24.7 to 64.1), 65.4% (95% CI, 24.5-85.9), 82.1% (95% CI, 58.4-92.5) and 92.2% (95% CI, 81.0-97.1) for placebo, 100, 200, and 400 mg tribendimidine, respectively. The Emax model predicted an ERR of 95% at 500 mg. Only mild adverse events and no abnormal biochemical parameters were observed.

CONCLUSION

A 400-mg dose of tribendimidine yielded the highest efficacy and was well tolerated. Because children were mostly lightly infected, further investigations with tribendimidine against moderate/heavy hookworm infection are needed.

CLINICAL TRIALS REGISTRATION

The trial is registered at www.isrctn.com number ISRCTN81391471.

Drug metabolism and pharmacokinetics of praziquantel: A review of variable drug exposure during schistosomiasis treatment in human hosts and experimental models

Schistosomiasis control is heavily reliant on the drug praziquantel (PZQ), which is used as preventive chemotherapy as part of national helminth control strategies. Given the heavy reliance on PZQ for mass drug administration, there has been considerable research on the potential of parasites developing resistance to the drug, resulting in decreased drug efficacy. However, there have been comparatively fewer studies of other factors that can potentially alter PZQ efficacy. Here, we investigate whether host PZQ metabolism contributes towards variable cure rates. We evaluate factors that can influence the metabolism of PZQ and the resultant effect on the efficacy of PZQ treatment to determine factors that potentially influence an individual's response to the drug. The literature search was directed at published studies from three online databases: Web of Science, PubMed, and EMBASE. The search terms for the review comprised of ([praziquantel OR PZQ] AND [schistosom* OR bilharzia] AND [pharmaco*]) and included studies evaluating PZQ metabolism. Publications were categorised into pharmacokinetics, drug-drug interactions, pharmacogenetics, and metabolite analysis. Forty publications describing human and experimental studies fitted the inclusion criteria and were subjected to data extraction and analysis. The analyses showed that variable exposure to PZQ was associated with alterations in the liver's capacity to metabolise PZQ and observed drug-drug interactions. Other factors influencing the efficacy of PZQ were brand, formulation, and co-administered food. Although some work has been performed on metabolite identification, there was minimal information on PZQ's metabolic pathway, and no pharmacogenetics studies were identified. The study indicated that in both human and experimental studies alterations in the liver's capacity to metabolise PZQ as well as drug-drug interactions affected systemic levels of PZQ that could result in variable cure rates. The study confirmed previous findings of higher antischistosomal activity of (R)-PZQ enantiomer when administered alone compared to the racemate at the same dose as well as improved efficacy when the drug is administered with food. The study also highlighted the need for more comprehensive studies of the PZQ metabolic pathway and PZQ pharmacogenetic studies in humans.

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.

H1-antihistamines as antischistosomal drugs: in vitro and in vivo studies

Background

Schistosomiasis is a socioeconomically devastating parasitic infection afflicting hundreds of millions of people and animals worldwide. It is the most important helminth infection, and its treatment relies solely on the drug praziquantel. Oral H1-antihistamines are available worldwide, and these agents are among the most widely used of all medications in children and adults. Given the importance of the drug repositioning strategy, we evaluated the antischistosomal properties of the H1-antihistamine drugs commonly used in clinical practices.

Methods

Twenty-one antihistamine drugs were initially screened against adult schistosomes ex vivo. Subsequently, we investigated the anthelmintic properties of these antihistamines in a murine model of schistosomiasis for both early and chronic S. mansoni infections at oral dosages of 400 mg/kg single dose or 100 mg/kg daily for five consecutive days. We also demonstrated and described the ability of three antihistamines to induce tegumental damage in schistosomes through the use of scanning electron microscopy.

Results

From phenotypic screening, we found that desloratadine, rupatadine, promethazine, and cinnarizine kill adult S. mansoni in vitro at low concentrations (5–15 µM). These results were further supported by scanning electron microscopy analysis. In an animal model, rupatadine and cinnarizine revealed moderate worm burden reductions in mice harboring either early or chronic S. mansoni infection. Egg production, a key mechanism for both transmission and pathogenesis, was also markedly inhibited by rupatadine and cinnarizine, and a significant reduction in hepatomegaly and splenomegaly was recorded. Although less effective, desloratadine also revealed significant activity against the adult and juvenile parasites.

Conclusions

Although the worm burden reductions achieved are all only moderate, comparatively, treatment with any of the three antihistamines is more effective in early infection than praziquantel. On the other hand, the clinical use of H1-antihistamines for the treatment of schistosomiasis is highly unlikely.

Change in schistosomiasis-related liver disease with repeated praziquantel treatment in school children in rural Zambia

Repeated praziquantel treatment for schistosomiasis is an effective method to reduce disease burden. Ultrasonographic methods were used to assess the severity of schistosoma mansoni-related liver disease and demonstrate improvement following treatment. We compared data from 733 children in 2010 and 972 children in 2018 to determine the effect of repeated praziquantel treatment on prevalence of liver disease. Three age groups were compared across three liver disease classifications (normal, mild, severe). From 2010 to 2018, there was a significant reduction in prevalence of severe liver disease in all age groups (P = 0.03 for 5-10 years, P < 0.001 for 11-15 years and 16-20 years). In both male and female students, the proportion having a normal liver significantly increased (P < 0.001) from 2010 to 2018, in the 11-15-year-olds and 16-20-year-olds, demonstrating that liver disease significantly reduced in these age groups. This study demonstrates a reduction in schistosomiasis-related morbidity with repeated praziquantel treatment.

Reassessing therapeutic antibodies for neglected and tropical diseases

In the past two decades there has been a significant expansion in the number of new therapeutic monoclonal antibodies (mAbs) that are approved by regulators. The discovery of these new medicines has been driven primarily by new approaches in inflammatory diseases and oncology, especially in immuno-oncology. Other recent successes have included new antibodies for use in viral diseases, including HIV. The perception of very high costs associated with mAbs has led to the assumption that they play no role in prophylaxis for diseases of poverty. However, improvements in antibody-expression yields and manufacturing processes indicate this is a cost-effective option for providing protection from many types of infection that should be revisited. Recent technology developments also indicate that several months of protection could be achieved with a single dose. Moreover, new methods in B cell sorting now enable the systematic identification of high-quality antibodies from humanized mice, or patients. This Review discusses the potential for passive immunization against schistosomiasis, fungal infections, dengue, and other neglected diseases.

Efficacy and Safety of Praziquantel for Treatment of Schistosoma mansoni Infection among School Children in Tanzania

Single-dose targeted praziquantel preventive chemotherapy is the WHO-recommended intervention for schistosomiasis control in endemic countries. The objective of this study was to assess the efficacy and safety of single-dose praziquantel among Schistosoma mansoni-infected children in north-western Tanzania. A prospective safety and efficacy surveillance study was conducted among 341 school-going children treated with a single-dose praziquantel 40 mg/kg body weight. Socio-demographic, pre-treatment, and post-treatment stool examination and safety data were collected. The primary and secondary outcomes were treatment efficacy (parasitological cure and egg reduction rates at three weeks post-treatment) and treatment-related adverse events, respectively. The overall cure rate and egg reduction rate were 81.2% (76.8–85.3%) and 95.0% (92.7–97.3%), respectively. There was no significant association between cure rate and pre-treatment infection intensity. The incidence of treatment-associated adverse events was 28.5% (23.7–33.3%), with abdominal pain being the most common. Post-treatment abdominal pain and vomiting were significantly associated with pre-treatment infection intensity (p < 0.001) and anemia (p = 0.03), respectively. Praziquantel single-dose is still safe and efficacious against Schistosoma mansoni infection. However, the lack of cure in about one-fifth and adverse events in a quarter, of the infected children indicate the need for close praziquantel safety monitoring and treatment optimization research to improve efficacy.

Exploring mechanochemical parameters using a DoE approach: Crystal structure solution from synchrotron XRPD and characterization of a new praziquantel polymorph

A rotated Doehlert matrix was utilized to explore the experimental design space around the milling parameters of Praziquantel (PZQ) polymorph B formation in terms of frequency and milling time. Three experimental responses were evaluated on the resulting ground samples: two quantitative responses, i.e. median particle size by Laser Light scattering (LLS) and drug recovery by HPLC, and one qualitative dependent variable, i.e. the obtained PZQ crystalline form, characterized through X-Ray Powder Diffraction (XRPD) and confirmed by Differential Scanning Calorimetry (DSC) and Thermogravimetric analysis (TGA). Temperature inside the jars was kept under constant control during the milling process by using temperature sensor equipped jars (thermojars), thus allowing evaluation of the obtained solid states at each experimental point, considering the specific temperature of the process. This explorative analysis led to the finding of a novel PZQ polymorph, named "Form C", produced without degradation, then fully characterized, including by means of Synchrotron XRPD, Polarimetric, FT-IR, SS-NMR, ESEM and saturation solubility. Crystal structure was solved from XRPD data and its geometry was optimized by DFT calculations (CASTEP). Finally, Form C and Form A activity against adult schistosoma mansoni were compared through in vitro testing, and Form C's physical stability checked. The new polymorph, crystallizing in space group I2/c, physically stable for approximately 2 months, showed a m.p. of 106.84 °C and displayed excellent biopharmaceutical properties (water solubility of 382.69±9.26 mg/l), while preserving excellent activity levels against adult schistosoma mansoni.

Non-sedating benzodiazepines cause paralysis and tissue damage in the parasitic blood fluke Schistosoma mansoni

Parasitic flatworm infections (e.g. tapeworms and fluke worms) are treated by a limited number of drugs. In most cases, control is reliant upon praziquantel (PZQ) monotherapy. However, PZQ is ineffective against sexually immature parasites, and there have also been several concerning reports on cestode and trematode infections with poor PZQ cure-rates, emphasizing the need for alternative therapies to treat these infections. We have revisited a series of benzodiazepines given the anti-schistosomal activity of meclonazepam (MCLZ). MCLZ was discovered in the 1970's but was not brought to market due to dose-limiting sedative side effects. However, in the decades since there have been advances in our understanding of the benzodiazepine GABAA receptor sub-types that drive sedation and the development of sub-type selective, non-sedating ligands. Additionally, the sequencing of flatworm genomes reveals that parasitic trematodes and cestodes have lost GABAAR-like ligand gated anion channels, indicating that MCLZ's anti-parasitic target is distinct from the human receptors that drive sedation. Therefore, we have screened a library of classical and non-sedating 1,4-benzodiazepines against Schistosoma mansoni and identified a series of imidazobenzodiazepines that immobilize worms in vitro. One of these hits, Xhe-II-048 also disrupted the parasite tegument, resulting in extensive vacuole formation beneath the apical membrane. The hit compound series identified has a dramatically lower (~1000×) affinity for the human central benzodiazepine binding site and is a promising starting point for the development of novel anti-schistosomal benzodiazepines with minimal host side-effects.

A prospective risk assessment of the implementation of a schistosomiasis preventive mass drug administration for children aged five years and below in the uMkhanyakude district of KwaZulu-Natal

Background

Schistosomiasis is endemic in the uMkhanyakude district of KwaZulu-Natal, South Africa. The South Africa Department of Health (DoH) has decided to implement a schistosomiasis preventive mass drug administration program in all affected parts of the country. Quality management is part of the strategic objectives of the treatment program. We conducted a risk assessment and developed guidelines for the quality management of a schistosomiasis preventive treatment program for children aged 5 years and below in the uMkhanyakude District of KwaZulu-Natal.

Methods

We conducted a scenario planning exercise by interviewing 10 child health experts from the uMkhanyakude Health District to establish potential risks associated with a planned schistosomiasis preventive control treatment program for children aged 5 years old and below. The risks were analyzed using a modified Failure Mode and Effect Analysis (FMEA). An FMEA table was produced to guide the quality management of the planned schistosomiasis preventive control treatment program for children aged 5 years and below in the uMkhanyakude Health District.

Results

We identified potential risks, failure modes and possible failure corrective/preventive measures in the following activities that would be part of the mass treatment of children aged 5 years and below infected with schistosomiasis in the uMkhanyakude District. These included enrolment of children into the treatment program; general health checks; weight and height measurements; administration of drugs; reporting of side effects and monitoring and evaluation.

Conclusion

We were able to use FMEA guide quality management and identify potential risks associated with the planned schistosomiasis preventive treatment program for children aged 5 years old and below in the uMkhanyakude District of KwaZulu-Natal. The FMEA for this program will be useful to the quality management of schistosomiasis preventive treatment programs for this age group in other similar settings.

Activity and pharmacokinetics of a praziquantel crystalline polymorph in the Schistosoma mansoni mouse model

Schistosomiasis is a global disease of significant public health relevance. Only one racemic drug, praziquantel, characterized by low bioavailability, low water solubility and extensive first pass metabolism, is currently available. We studied a new praziquantel formulation (polymorph B), which is based on a racemic praziquantel crystalline polymorph (TELCEU01). Its in vitro activity was tested on newly transformed schistosomula (NTS) and adult Schistosoma mansoni. In vivo studies were conducted in mice harboring chronic S. mansoni infections. Pharmacokinetic (PK) profiles of R- and S-praziquantel and R- and S- polymorph B following oral administration with both formulations were generated by sampling mice at 30, 60, 240 min and 24 h post-treatment, followed by LC-MS/MS analysis. PK parameters were calculated using a non-compartmental analysis with a linear trapezoidal model. In vitro, commercial praziquantel and the polymorph B performed similarly on both NTS (IC₅₀ = 2.58 and 2.40 µg/mL at 72 h) and adults (IC₅₀ = 0.05 and 0.07 µg/mL at 72 h). Praziquantel showed higher in vivo efficacy with an ED₅₀ of 58.75 mg/kg compared to an ED₅₀ of 122.61 mg/kg for the polymorph B. The PK profiles of the two drugs exhibited differences: R-praziquantel showed an overall 40% higher area under the plasma drug concentration-time curve (AUC_0→24) (R-praziquantel = 3.42; R-polymorph B = 2.05 h*µg/mL) and an overall 30% lower apparent clearance (Cl/F) (R-praziquantel = 70.68 and R-polymorph B = 97.63 (mg)/(µg/mL)/h). Despite the lack of improved activity and PK properties of polymorph B against S. mansoni, here presented; research on pharmaceutical polymorphism remains a valid and cost-effective option for the development of new praziquantel formulations with enhanced properties such as increased solubility and/or dissolution.

Relative Bioavailability of Orally Dispersible Tablet Formulations of Levo- and Racemic Praziquantel: Two Phase I Studies

Orally dispersible tablet (ODT) formulations of levo praziquantel (L-PZQ) and racemic PZQ (rac-PZQ) are being developed to treat schistosomiasis in preschool-aged children. Two crossover studies (N = 32 and 36, respectively) assessed the relative bioavailability of these ODTs vs. Cysticide in adults. Bioavailability for L-PZQ of ODT rac-PZQ and Cysticide at 40 mg/kg was comparable (L-PZQ area under the concentration-time curve from zero to infinity (AUC0-∞ ) test/reference ratio (90% confidence interval (CI)): 96% (84-111%)), whereas relative bioavailability of ODT L-PZQ 20 mg/kg was ~40% that of Cysticide 40 mg/kg (test/reference: 40% (35-46%)). AUC0-∞ and peak plasma concentration (Cmax ) were highly variable in both studies. For both ODTs, L-PZQ AUC0-∞ showed greater than dose-proportional increase over the ranges tested and a significant food effect. Safety was comparable among formulations. The lower bioavailability of ODT L-PZQ, as well as the high variability and nondose-proportionality of pharmacokinetic (PK) parameters, highlighted the need for a dedicated pediatric dose-finding study for the selection of the most appropriate formulation and dose (L-PZQ ODT or rac-PZQ ODT).

Accuracy of the WHO praziquantel dose pole for large-scale community treatment of urogenital schistosomiasis in northern Mozambique: Is it time for an update?

BACKGROUND

A pioneering strategy developed by the World Health Organization (WHO) for the control of schistosomiasis was the concept of a height-based dose pole to determine praziquantel (PZQ) dosing in large-scale treatment campaigns. However, some recent studies have shown variable accuracy for the dose pole in terms of predicting correct mg/Kg dosing, particularly for treatment of adults. According to the WHO, 91 million adults in 52 countries are targeted to be treated by 2020.

METHODS/PRINCIPAL FINDINGS

The present study aimed to test the accuracy of the dose pole in determining PZQ dosage by comparing the number of tablets determined by the dose pole with the number of tablets determined according to total body weight. The analysis included height-for-weight data from 9,827 school-aged children (SAC) and adults from 42 villages in the province of Cabo Delgado in Mozambique. The results revealed that of the 7,596 SAC, 91.8% has received an appropriate dose (30-60mg/Kg), 6% received an insufficient dose (<30mg/Kg) and 2% an excessive dose (> 60mg/Kg). On the other hand, 13.7% out of 2,231 adults were treated inaccurately with 13.5% receiving an insufficient dose and 0.2% an excessive dose. When the percentage of insufficient dosing was disaggregated by gender, the frequency of adult females who were underdosed reached 18.3% versus 10.8% of adult males. Of note, Adult females aged 21-55 years were found to have an underdose frequency of 21.3%, compared to 11.8% of adult males in the same age range. The performance of a proposed modified dose pole was compared using the same dataset of adult Mozambicans. The results showed that the modified dose pole reduced the underdose frequency among adults from 13.5% to 10.4%, and subsequently increased the percentage of optimal dosing from 33.7% to 45.3%.

CONCLUSIONS

Our findings highlight the need to update the WHO-dose pole to avoid administration of insufficient PZQ doses to adults and therefore minimize the potential emergence of PZQ-resistant strains.

TRIAL REGISTRATION

International Standard Randomized Controlled Trial registry under ISRTC number 14117624.

Challenges and Lessons From Conducting A Paediatric Clinical Trial in Sub-Saharan Africa: The Case of the Praziquantel Oral Dispersible Tablets Phase II Study in Côte d'Ivoire

The importance of implementing paediatric clinical trials for neglected tropical diseases (NTDs) in compliance with the Good Clinical Practices of the International Conference of Harmonisation (ICH-GCP) and other applicable regulatory and ethics guidelines is increasingly being recognised as an essential pathway to provide safe and effective medicines for millions of untreated children living in sub-Saharan Africa (SSA). This paper describes the learnings and challenges faced by the Pediatric Praziquantel Consortium team during the implementation of an industry-sponsored Phase II clinical study in pre-school-aged children infected with schistosomiasis, conducted in remote rural settings in Côte d'Ivoire. The importance of close interactions with the ethics committee, the regulatory and administrative authorities and the rural communities are highlighted. The difficulties faced included obtaining a valid informed consent from the child's parent or guardian, the collection of blood samples from children during the study while respecting cultural beliefs as well as the weak medical research infrastructure. The paper illustrates how a public-private collaborative partnership can promote capacity-building and high-quality NTD paediatric clinical research in SSA.

Structure-activity profiling of alkaloid natural product pharmacophores against a Schistosoma serotonin receptor

Serotonin (5-HT) is an important regulator of numerous aspects of flatworm biology, ranging from neuromuscular function to sexual maturation and egg laying. In the parasitic blood fluke Schistosoma mansoni, 5-HT targets several G-protein coupled receptors (GPCRs), one of which has been demonstrated to couple to cAMP and regulate parasite movement. This receptor, Sm.5HTR_L, has been successfully co-expressed in mammalian cells alongside a luminescent cAMP-biosensor, enabling pharmacological profiling for candidate anti-schistosomal drugs. Here, we have utilized this assay to perform structure-activity investigations of 143 compounds containing previously identified alkaloid natural product pharmacophores (tryptamines, aporphines and protoberberines) shown to regulate Sm.5HTR_L. These experiments mapped regions of the tryptamine pharmacophore amenable and intolerant to substitution, highlighting differences relative to orthologous mammalian 5-HT receptors. Potent Sm.5HTR_L antagonists were identified, and the efficacy of these compounds were evaluated against live adult parasites cultured ex vivo. Such structure-activity profiling, characterizing the effect of various modifications to these core ring systems on Sm.5HTR_L responses, provides greater understanding of pharmacophores selective for this target to aid future drug development efforts.

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Various alkaloids were screened against a schistosome serotonin receptor, Sm.5HTR_L.

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Compounds with a tryptamine core displayed agonist activity at Sm.5HTR_L.

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Aporphine and protoberberine compounds displayed antagonist activity at Sm.5HTR_L.

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Compound activity at Sm.5HTR_L is broadly mirrored by motility effects on adult worms.

Extrapolation of praziquantel pharmacokinetics to a pediatric population: a cautionary tale

L-praziquantel (PZQ) pharmacokinetic data were analyzed from two relative bioavailability Phase 1 studies in adult, healthy subjects with two new oral dispersion tablet (ODT) formulations of L-PZQ administered under various combinations of co-administration with food, water, and/or crushing. Linear mixed effects models adequately characterized the noncompartmental estimates of the pharmacokinetic profiles in both studies. Dose, food, and formulation were found to significantly affect L-PZQ exposure in both studies. The model for AUC was then extrapolated to children 2–5 years old accounting for enzyme maturation and weight. The predicted exposures were compared to an external Phase 1 study conducted by the Swiss Tropical and Public Health Institute using a currently marketed formulation (Cesol 600 mg immediate-release tablets) and found to be substantially lower than observed. A root cause analysis was completed to identify the reason for failure of the models. Various scenarios were proposed and tested. Two possible reasons for the failure were identified. One reason was that the model did not account for the reduced hepatic clearance seen in patients compared to the healthy volunteer population used to build the model. The second possible reason was that PZQ absorption appears sensitive to meal composition and the model did not account for differences in meals between a standardized Phase 1 unit and clinical sites in Africa. Further studies are needed to confirm our hypotheses.

Pharmacokinetics of Praziquantel in Schistosoma mansoni- and Schistosoma haematobium-Infected School- and Preschool-Aged Children

There is a growing consensus to include preschool-aged children in preventive chemotherapy programs with praziquantel to improve schistosomiasis control. However, pharmacokinetic data, crucial to establish a safe and effective dose for this age group, are sparse. The objective of this study was to establish and compare the pharmacokinetic parameters of praziquantel in preschool- and school-aged children with schistosomiasis. Two pharmacokinetic trials in school- and preschool-aged children infected with Schistosoma mansoni or S. haematobium were conducted in Côte d'Ivoire. Dried blood spot samples were taken from 492 children at 10 time points following a single oral dose of 20, 40, or 60 mg/kg of body weight of praziquantel and analyzed using liquid chromatography-mass spectrometry. Noncompartmental analysis (NCA) was performed to obtain the pharmacokinetic parameters of R-praziquantel (RPZQ), S-praziquantel (SPZQ), and R-trans-4-hydroxy-praziquantel. No significant differences in pharmacokinetic parameters between species-specific infections were observed. While pharmacokinetic parameters differed significantly between age groups for S. mansoni, this trend was not observed with S. haematobium Neither the area under the curve (AUC) nor the maximal blood concentration (C_max) presented clear dose proportionality for R- and SPZQ. Logistic regression indicated a relationship between the RPZQ AUC and C_max and the probability of cure. Praziquantel is subject to complex metabolic processes following erratic absorption. While the results of NCA are a very informative base for a better understanding of the drug, a more targeted approach in the form of population modeling is needed to quantify the factors influencing metabolic processes and draw conclusions.

Efficacy of praziquantel treatment regimens in pre-school and school aged children infected with schistosomiasis in sub-Saharan Africa: a systematic review

BACKGROUND

Schistosomiasis is a serious public health burden in sub-Saharan Africa. Praziquantel is the only drug recommended by the World Health Organization to treat both urogenital and intestinal schistosomiasis. The reliance on a single drug to treat a disease with such a huge burden has raised concerns of possible drug resistance mainly in endemic areas. This systematic review was conducted to identify gaps and recent progress on the efficacy of different regimens of praziquantel in treating schistosomiasis among children in sub-Saharan Africa where Schistosoma mansoni and S. haematobium are endemic.

MAIN TEXT

A literature search of peer-reviewed journals was done on Google Scholar, MEDLINE (under EBSCOhost) and PubMed databases using pre-defined search terms and Boolean operators. The search included studies published from 2008 to 2017 (August) with emphasis on the efficacy of praziquantel on S. haematobium and S. mansoni infections among preschool and school children. Nineteen publications satisfied the inclusion criteria for the review. The studies reviewed were from 10 sub-Saharan African countries and 7/19 of the studies (37%) were conducted in Uganda. Seven studies (37%) focused on Schistosoma mansoni, 6/19 (31.5%) on S. haematobium and another 6 on mixed infection. A single standard dose of 40 mg/kg body weight was the most used regimen (9) followed by the repeated single standard dose assessed for efficacy at 3-4 weeks post-treatment.

CONCLUSIONS

A repeated standard dose of 40 mg/kg achieved satisfactory efficacy compared to a single dose against both parasite species. However, findings on efficacy of repeated doses in co-infection of S. mansoni and S. haematobium were not conclusive. Praziquantel administrated at 60 mg/kg was slightly more efficacious than the 40 mg/kg standard dose. Minor and transitory side-effects were reported for both regimens. The review indicates that further investigations are necessary to conclusively determine efficacy of praziquantel on coinfection of S. haematobium and S. mansoni to formulate concrete guidelines on the use of repeated doses at 40 or 60 mg/kg for treating schistosomiasis. We recommend the use of the egg reduction rate (ERR) formula recommended by the WHO for assessing praziquantel efficacy in order for the results to be comparable for different regions.

Efficacy and safety of ascending doses of praziquantel against Schistosoma haematobium infection in preschool-aged and school-aged children: a single-blind randomised controlled trial

BACKGROUND

Despite decades of experience with praziquantel treatment in school-aged children (SAC) and adults, we still face considerable knowledge gaps relevant to the successful treatment of preschool-aged children (PSAC). This study aimed to assess the efficacy and safety of escalating praziquantel dosages in PSAC infected with Schistosoma haematobium.

METHODS

We conducted a randomised, dose-finding trial in PSAC (2-5 years) and as comparator a cohort of SAC (6-15 years) infected with S. haematobium in Côte d'Ivoire. A total of 186 PSAC and 195 SAC were randomly assigned to 20, 40 or 60 mg/kg praziquantel or placebo. The nature of the dose-response relationship in terms of cure rate (CR) was the primary objective. Egg reduction rate (ERR) and tolerability were secondary outcomes. CRs and ERRs were assessed using triplicate urine filtration over 3 consecutive days. Available-case analysis was performed including all participants with primary endpoint data.

RESULTS

A total of 170 PSAC and 174 SAC received treatment. Almost 90% of PSAC and three quarters of SAC were lightly infected with S. haematobium. Follow-up data were available for 157 PSAC and 166 SAC. In PSAC, CRs of praziquantel were 85.7% (30/35), 78.0% (32/41) and 68.3% (28/41) at 20, 40 and 60 mg/kg and 47.5% (19/40) for placebo. In SAC, CRs were 10.8% for placebo (4/37), 55.6% for 20 mg/kg (25/45), 68.3% for 40 mg/kg (28/41) and 60.5% for 60 mg/kg (26/43). ERRs based on geometric means ranged between 96.5% (60 mg/kg) and 98.3% (20 mg/kg) in PSAC and between 97.6% (20 mg/kg and 60 mg/kg) and 98.6% (40 mg/kg) in SAC. Adverse events were mild and transient.

CONCLUSIONS

Praziquantel revealed dose-independent efficacy against light infections of S. haematobium. Over the dose range tested, praziquantel displayed a ceiling effect with the highest response for 20 mg/kg in PSAC. In SAC maximum efficacy was obtained with 40 mg/kg praziquantel. Further investigations are required in children with moderate to heavy infections.

TRIAL REGISTRATION

This trial is registered with International Standard Randomised Controlled Trial Number ISRCTN15280205 .

Characterizing the Biochemical Response to Schistosoma mansoni Infection and Treatment with Praziquantel in Preschool and School Aged Children

Schistosomiasis is a widespread chronic neglected tropical disease prevalent mostly in children in under-resourced rural areas. Its pathological effects have been clinically characterized, yet the molecular-level effects are understudied. In this study, the biochemical effects of Schistosoma mansoni infection and praziquantel treatment were studied in 130 preschool aged and 159 school aged infected children and 11 noninfected children in Azaguié, Côte d'Ivoire. Urine samples were collected prior to receiving 20, 40, or 60 mg/kg of praziquantel or a placebo, as well as 24 h post-treatment, and at the 3-week follow up. Urinary metabolic phenotypes were measured using ¹H NMR spectroscopy, and metabolic variation associated with S. mansoni infection and praziquantel administration was identified using multivariate statistical techniques. Discriminatory metabolic signatures were detected between heavily infected and noninfected children at baseline as well as according to the dose of praziquantel administered 24 h post treatment. These signatures were primarily associated with the metabolic activity of the gut microbiota, gut health and growth biomarkers and energy and liver metabolism. These analyses provide insights into the metabolic phenotype of schistosomiasis and treatment with praziquantel in two important demographics.

Investigations on the interplays between Schistosoma mansoni, praziquantel and the gut microbiome

Background

Schistosomiasis is a neglected tropical disease burdening millions of people. One drug, praziquantel, is currently used for treatment and control. Clinically relevant drug resistance has not yet been described, but there is considerable heterogeneity in treatment outcomes, ranging from cure to only moderate egg reduction rates. The objectives of this study are to investigate potential worm-induced dysbacteriosis of the gut microbiota and to assess whether a specific microbiome profile could influence praziquantel response.

Methods

Using V3 and V4 regions of 16S rRNA genes, we screened the gut microbiota of 34 Schistosoma mansoni infected and uninfected children from Côte d’Ivoire. From each infected child one pre-treatment, one 24-hour and one 21-day follow-up sample after administering 60 mg/kg praziquantel or placebo, were collected.

Results

Overall taxonomic profiling and diversity indicators were found to be close to a “healthy” gut structure in all children. Slight overall compositional changes were observed between S. mansoni-infected and non-infected children. Praziquantel treatment was not linked to a major shift in the gut taxonomic profiles, thus reinforcing the good safety profile of the drug by ruling out off-targets effects on the gut microbes.16S rRNA gene of the Fusobacteriales order was significantly more abundant in cured individuals, both at baseline and 24 hours post-treatment. A real-time qPCR confirmed the over-abundance of Fusobacterium spp. in cured children. Fusobacterium spp. abundance could also be correlated with treatment induced S. mansoni egg-reduction.

Conclusions

Our study suggests that neither a S. mansoni infection nor praziquantel administration triggers a significant effect on the microbial composition and that a higher abundance of Fusobacterium spp., before treatment, is associated with higher efficacy of praziquantel in the treatment of S. mansoni infections.

Trial registration

International Standard Randomised Controlled Trial, number ISRCTN15280205.

Electronic supplementary material

The online version of this article (10.1186/s13071-018-2739-2) contains supplementary material, which is available to authorized users.

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

Schistosomiasis affects over 200 million people worldwide, most of whom are children. Research and control strategies directed at preschool-aged children (PSAC), i.e., ≤5 years old, have lagged behind those in older children and adults. With the recent WHO revision of the schistosomiasis treatment guidelines to include PSAC, and the recognition of gaps in our current knowledge on the disease and its treatment in this age group, there is now a concerted effort to address these shortcomings. Global and national schistosome control strategies are yet to include PSAC in treatment schedules. Maximum impact of schistosome treatment programmes will be realised through effective treatment of PSAC. In this review, we (i) discuss the current knowledge on the dynamics and consequences of paediatric schistosomiasis and (ii) identify knowledge and policy gaps relevant to these areas and to the successful control of schistosome infection and disease in this age group. Herein, we highlight risk factors, immune mechanisms, pathology, and optimal timing for screening, diagnosis, and treatment of paediatric schistosomiasis. We also discuss the tools required for treating schistosomiasis in PSAC and strategies for accessing them for treatment.