Efficacy of artesunate and praziquantel in Schistosoma haematobium infected schoolchildren

A reanalysis and integration of transcriptomics and proteomics datasets unveil novel drug targets for Mekong schistosomiasis

Schistosomiasis, caused by Schistosoma trematodes, is a significant global health concern, particularly affecting millions in Africa and Southeast Asia. Despite efforts to combat it, the rise of praziquantel (PZQ) resistance underscores the need for new treatment options. Protein kinases (PKs) are vital in cellular signaling and offer potential as drug targets. This study focused on focal adhesion kinase (FAK) as a candidate for anti-schistosomal therapy. Transcriptomic and proteomic analyses of adult S. mekongi worms identified FAK as a promising target due to its upregulation and essential role in cellular processes. Molecular docking simulations assessed the binding energy of FAK inhibitors to Schistosoma FAK versus human FAK. FAK inhibitor 14 and PF-03814735 exhibited strong binding to Schistosoma FAK with minimal binding for human FAK. In vitro assays confirmed significant anti-parasitic activity against S. mekongi, S. mansoni, and S. japonicum, comparable to PZQ, with low toxicity in human cells, indicating potential safety. These findings highlight FAK as a promising target for novel anti-schistosomal therapies. However, further research, including in vivo studies, is necessary to validate efficacy and safety before clinical use. This study offers a hopeful strategy to combat schistosomiasis and reduce its global impact.

New clinical application prospects of artemisinin and its derivatives: a scoping review

BACKGROUND

Recent research has suggested that artemisinin and its derivatives may have therapeutic effects on parasites, viruses, tumors, inflammation and skin diseases. This study aimed to review clinical research on artemisinin and its derivatives except anti-malaria and explore possible priority areas for future development.

METHODS

Relevant articles in English and Chinese published before 28 October 2021 were reviewed. All articles were retrieved and obtained from databases including WanFang, PubMed/MEDLINE, the Cochrane Library, China National Knowledge International, Embase, OpenGrey, the Grey Literature Report, Grey Horizon, and ClinicalTrials.gov. Studies were selected for final inclusion based on predefined criteria. Information was then extracted and analyzed by region, disease, outcome, and time to identify relevant knowledge gaps.

RESULTS

Seventy-seven studies on anti-parasitic (35), anti-tumor (16), anti-inflammatory (12), anti-viral (8), and dermatological treatments (7) focused on the safety and efficacy of artemisinin and its derivatives. The anti-parasitic clinical research developed rapidly, with a large number of trials, rapid clinical progress, and multiple research topics. In contrast, anti-viral research was limited and mainly stayed in phase I clinical trials (37.50%). Most of the studies were conducted in Asia (60%), followed by Africa (27%), Europe (8%), and the Americas (5%). Anti-parasite and anti-inflammatory research were mainly distributed in less developed continents such as Asia and Africa, while cutting-edge research such as anti-tumor has attracted more attention in Europe and the United States. At the safety level, 58 articles mentioned the adverse reactions of artemisinin and its derivatives, with only one study showing a Grade 3 adverse event, while the other studies did not show any related adverse reactions or required discontinuation. Most studies have discovered therapeutic effects of artemisinin or its derivatives on anti-parasitic (27), anti-tumor (9), anti-inflammatory (9) and dermatological treatment (6). However, the efficacy of artemisinin-based combination therapies (ACTs) for parasitic diseases (non-malaria) is still controversial.

CONCLUSIONS

Recent clinical studies suggest that artemisinin and its derivatives may be safe and effective candidates for anti-tumor, anti-parasitic, anti-inflammatory and dermatological drugs. More phase II/III clinical trials of artemisinin and its derivatives on antiviral effects are needed.

Urogenital schistosomiasis in three different water access in the Senegal river basin: prevalence and monitoring praziquantel efficacy and re-infection levels

BACKGROUND

Urogenital schistosomiasis is a neglected tropical disease most prevalent in sub-Saharan Africa. In the Senegal river basin, the construction of the Diama dam led to an increase and endemicity of schistosomiasis. Since 2009, praziquantel has frequently been used as preventive chemotherapy in the form of mass administration to Senegalese school-aged children without monitoring of the treatment efficacy and the prevalence after re-infection. This study aims to determine the current prevalence of urogenital schistosomiasis (caused by Schistosoma haematobium), the efficacy of praziquantel, and the re-infection rates in children from five villages with different water access.

METHODS

The baseline prevalence of S. haematobium was determined in August 2020 in 777 children between 5 and 11 years old and a single dose of praziquantel (40 mg/kg) was administered to those positive. The efficacy of praziquantel and the re-infection rates were monitored 4 weeks and 7 months after treatment, respectively, in 226 children with a high intensity of infection at baseline.

RESULTS

At the baseline, prevalence was low among children from the village of Mbane who live close to the Lac de Guiers (38%), moderate among those from the villages of Dioundou and Khodit, which neighbor the Doue river (46%), and very high at Khodit (90.6%) and Guia (91.2%) which mainly use an irrigation canal. After treatment, the observed cure rates confirmed the efficacy of praziquantel. The lowest cure rate (88.5%) was obtained in the village using the irrigation canal, while high cure rates were obtained in those using the lake (96.5%) and the river (98%). However, high egg reduction rates (between 96.7 and 99.7%) were obtained in all the villages. The re-infection was significantly higher in the village using the canal (42.5%) than in the villages accessing the Lac de Guiers (18.3%) and the Doue river (14.8%).

CONCLUSION

Praziquantel has an impact on reducing the prevalence and intensity of urogenital schistosomiasis. However, in the Senegal river basin, S. haematobium remains a real health problem for children living in the villages near the irrigation canals, despite regular treatment, while prevalence is declining from those frequenting the river and the Lac de Guiers. Trial registration ClinicalTrials.gov, NCT04635553. Registered 19 November 2020 retrospectively registered, https://www.

CLINICALTRIALS

gov/ct2/show/NCT04635553?cntry=SN&draw=2&rank=4.

Protein Kinases: Potential Drug Targets Against Schistosoma japonicum

Schistosoma japonicum (S. japonicum) infection can induce serious organ damage and cause schistosomiasis japonica which is mainly prevalent in Asia and currently one of the most seriously neglected tropical diseases. Treatment of schistosomiasis largely depends on the drug praziquantel (PZQ). However, PZQ exhibits low killing efficacy on juvenile worms and the potential emergence of its drug resistance is a continual concern. Protein kinases (PKs) are enzymes that catalyze the phosphorylation of proteins and can participate in many signaling pathways in vivo. Recent studies confirmed the essential roles of PKs in the growth and development of S. japonicum, as well as in schistosome-host interactions, and researches have screened drug targets about PKs from S. japonicum (SjPKs), which provide new opportunities of developing new treatments on schistosomiasis. The aim of this review is to present the current progress on SjPKs from classification, different functions and their potential to become drug targets compared with other schistosomes. The efficiency of related protein kinase inhibitors on schistosomes is highlighted. Finally, the current challenges and problems in the study of SjPKs are proposed, which can provide future guidance for developing anti-schistosomiasis drugs and vaccines.

20-Hydroxy-3-Oxolupan-28-Oic Acid, a Minor Component From Mahonia bealei (Fort.) Carr. Leaves Alleviates Lipopolysaccharide-Induced Inflammatory in Murine Macrophages

20-Hydroxyl-3-oxolupan-28-oic acid (HOA), a minor component from Mahonia bealei (Fort.) Carr. leaves, has been found to attenuate inflammatory responses. However, the underlying molecular mechanism is still unclear. In this study, we performed a comprehensive transcriptional study to investigate genetic changes. We used RNA sequencing technology to analyses the transcriptional changes in RAW 264.7 cells in a control group, lipopolysaccharide (LPS)-induced group, and HOA-treated group. We identified 1,313 and 388 differentially expressed genes (DEGs) in the control/LPS group and LPS/HOA group, respectively. Gene Ontology (GO) classification revealed that the DEGs were mainly enriched in a series of inflammatory and immune-related processes. The results of Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses showed that the DEGs were mainly enriched in inflammatory-related pathways such as the nuclear factor-kappa B (NF-κB) signaling pathway, cytokine-cytokine receptor interaction, chemokine signaling pathway, mitogen-activated protein kinase (MAPK) pathway, and Janus kinase-signal transducer and activator of transcription proteins (JAK-STAT) signaling pathway. The results of qPCR validation revealed that dynamic changes in immune-related mRNAs such as Saa3, Bcl2l1, Mapkapk2, Ccl9, Sdc4, Ddx3x, Socs3, Prdx5, Tlr4, Lif, IL15, Tnfaip3, Tet2, Tgf-β1, and Ccl20, which were significantly upregulated in the LPS group and downregulated in the HOA group. Taken together, these results suggest that HOA may be used as a source of anti-inflammatory agents as well as a dietary complement for health promotion.

PZQ Therapy: How Close are we in the Development of Effective Alternative Anti-schistosomal Drugs?

Today schistosomiasis, caused mainly by the three major schistosome species (S. mansoni, S. haematobium and S. japonicum), has for many decades and still continues to be on a rapid and swift rise globally, claiming thousands of lives every year and leaving 800 million people at the risk of infection. Due to the high prevalence of this disease and the steady increase in the infection rates, praziquantel (PZQ) remains the only effective drug against this acute disease although it has no effect on the juvenile schistosome parasite. However, no significant approaches have been made in recent years in the discovery of new or alternative drugs and unfortunately, resistance to this drug has been reported in some parts of the world. Therefore, it is imperative to develop a new drug for this debilitating disease. In this review, a brief history of past, present, and new promising anti-schistosomal drugs is presented.

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.

Infection status and risk factors associated with urinary schistosomiasis among school-going children in the Ndumo area of uMkhanyakude District in KwaZulu-Natal, South Africa two years post-treatment

OBJECTIVES

To assess the efficacy of praziquantel in children infected with Schistosoma haematobium over a 2-year period in the Ndumo area of uMkhanyakude District, South Africa.

METHODS

This cohort study enrolled 173 school-going children in September 2017 who had participated in a baseline survey conducted in 2015 in the Ndumo area. Questionnaire interviews were conducted to collect information on the risk factors related to the transmission of schistosomiasis. The filtration technique was performed to detect Schistosoma haematobium eggs in urine. Infection intensity was classified as light or heavy. The Chi-square test was used to assess the associations between variables at the 95% confidence level, and p=0.05 was considered significant.

RESULTS

Of the 173 participants screened 2 years post-treatment, 10 were infected. Six of these were new infection cases, while four were cases of re-infection. The intensity of infection had decreased significantly (p=0.001) at the time of the follow-up survey compared to the baseline survey. However, no significant difference was found among the risk factors for schistosomiasis 2 years later.

CONCLUSIONS

The prevalence of S. haematobium had decreased significantly in the cohort at 2 years post praziquantel treatment, during a period of persistent drought in the area. Risk factors that were significantly associated with schistosomiasis at baseline were no longer significantly associated at 2 years following treatment.

Efficacy of praziquantel on Schistosoma haematobium and re-infection rates among school-going children in the Ndumo area of uMkhanyakude district, KwaZulu-Natal, South Africa

BACKGROUND

Despite its low cure rates and possible resistance, praziquantel (PZQ) is the only drug available for schistosomiasis treatment. Hence, monitoring its efficacy is crucial. This study assessed the efficacy of PZQ, determined re-infection and incidence rates of Schistosoma haematobium infection among school-going children in the Ndumo area, KwaZulu-Natal.

METHODS

A cohort of 320 school-going children (10 - 15 years) in 10 primary schools was screened for S. haematobium infection using the filtration technique. Infected children were treated at different times and hence were divided into two sub-cohorts; A1 and A2. Non-infected children constituted the sub-cohort B. Children who continued excreting viable eggs 4 weeks post-treatment received a second dose of PZQ. Re-infection rates were determined in sub-cohort A1 and A2 at 28 and 20 weeks post-treatment, respectively. Cure rates (CR) and egg reduction rates (ERR) were calculated. Incidence rate was assessed 28 weeks post baseline survey using children that were negative for schistosome eggs at that survey. Analysis of data was done using the Chi square and the Wilcoxon rank test. A 95% confidence interval with a P-value < 0.05 determined significance.

RESULTS

At baseline, 120 (37.5%) of the 320 study participants were found infected with Schistosoma haematobium. Heavy infections accounted for 36.7%. The calculated cure rates were 88.07% and 82.92% for females and males, respectively. Egg Reduction Rates of 80% and 64% for females and males were observed 4 weeks after the initial treatment. After the second treatment, CR was 100% in females and 50% in males with an ERR of 100% in females and 70% in males. At 20 and 28 weeks post treatment, reinfection rates of 8.03% and 8.00% were observed, respectively, giving an overall rate of 8.1%. An incidence rate of 4.1% was observed 28 weeks after the baseline screening.

CONCLUSIONS

The study indicated high CR while the ERR was low suggesting a reduced PZQ efficacy. The efficacy improved among females after the second dose. Re-infection rates at 20 and 28 weeks post-treatment were low. The study also indicated a low incidence rate for the 28 weeks period.

Efficacy and safety of praziquantel 40 mg/kg in preschool-aged and school-aged children: a meta-analysis

BACKGROUND

Children carry most of the schistosomiasis burden. While school-aged children are the principal target group of preventive chemotherapy with praziquantel, limited information on efficacy and safety exists for preschool-aged children.

METHODS

Here, we conducted a meta-analysis of clinical trials of praziquantel for treating children with any form of schistosomiasis. Efficacy was reported as cure rate (CR) and egg reduction rates (ERR); statistical corrections were applied based on methodological disparities across trials to derive the predicted geometrical mean ERR (pERRgm). Safety was reported as frequencies of adverse events.

RESULTS

Forty-seven comparative and non-comparative studies were identified, enrolling 15,549 children of whom 14,340 (92%) were assessed between 3 and 8 weeks post-treatment with praziquantel 40 mg/kg (the WHO-recommended treatment, n = 8,380, 56%) or comparators (n = 5,960, 44%). The median age was 10 years (range 1-19), 11% (n = 1,694) were preschool-aged. The CR and pERRgm with praziquantel 40 mg/kg were respectively: S. haematobium, 73.6% (95% CI: 63.5-81.40, 25 study arms) and 94.7% (95% CI: 92.7-96.4); S. mansoni, 76.4% (95% CI: 71.5-81.0, 34 arms) and 95.3% (95% CI: 94.2-96.2); S. mansoni/S. haematobium, 67.6% (95% CI: 54.1-80.7, 5 arms) and 93.4% (95% CI: 89.9-96.2); S. japonicum, 94.7% (95% CI: 92.2-98.0) and 98.7% (95% CI: 98.3-99.2). Mixed-effect multivariate analysis found no significant difference between preschool- and school-aged children for CR or pERRgm in S. haematobium (P = 0.309 and P = 0.490, respectively) or S. mansoni (P = 0.982 and P = 0.895) after controlling for time of assessment, formulation, intensity of infection and detection method. Praziquantel was reportedly safe at all ages, with only mild reported adverse events which cleared rapidly after treatment.

CONCLUSIONS

Praziquantel 40 mg/kg was effective at reducing infection intensity in all Schistosoma species without differences between preschool- and school-aged children. However, conclusions should be tempered because of the limited number of preschool-aged children enrolled, disparities in study procedures and limited information made available in publications, as well as the current imperfect test-of-cure. Also, although reportedly well-tolerated, safety was inconsistently assessed. Studies in target groups, individual-data meta-analysis and standardised methodologies are needed for more robust evidence-base.

Impact of Annual Praziquantel Treatment on Urogenital Schistosomiasis in a Seasonal Transmission Focus in Central Senegal

In Sub-Saharan Africa, urogenital schistosomiasis remains a significant public health problem, causing 150.000 deaths/year with approximately 112 million cases diagnosed. The Niakhar district is a disease hotspot in central Senegal where transmission occurs seasonally with high prevalences. The aim of this study was to determine the effect of annual treatment over 3 years on the seasonal transmission dynamics of S. haematobium in 9 villages in the Niakhar district. Adults and children aged between 5 and 60 years were surveyed from 2011 to 2014. Urine samples were collected door-to-door and examined for S. haematobium eggs at baseline in June 2011, and all participants were treated in August 2011 with PZQ (40 mg/kg). After this initial examination, evaluations were conducted at 3 successive time points from September 2011 to March 2014, to measure the efficacy of the annual treatments and the rates of reinfection. Each year, during the transmission period, from July to November-December, malacological surveys were also carried out in the fresh water bodies of each village to evaluate the infestation of the snail intermediate hosts. At baseline, the overall prevalence of S. haematobium infection was 57.7%, and the proportion of heavy infection was 45.3%, but one month after the first treatment high cure rates (92.9%) were obtained. The overall infection prevalence and proportion of heavy infection intensities were drastically reduced to 4.2% and 2.3%, respectively. The level of the first reinfection in February-March 2012 was 9.5%. At follow-up time points, prevalence levels varied slightly between reinfection and treatment from 9.5% in June 2012 to 0.3% in March 2013, 11.2 in June 2013, and 10.1% April 2014. At the end of the study, overall prevalence was significantly reduced from 57.7% to 10.1%. The overall rate of infested Bulinid snails was reduced after repeated treatment from 0.8% in 2012 to 0.5% in 2013. Repeated annual treatments are suggested to have a considerable impact on the transmission dynamics of S. haematobium in Niakhar, due to the nature of the epidemiological system with seasonal transmission. Thus, to maintain this benefit and continue to reduce the morbidity of urogenital schistosomiasis, other approaches should be integrated into the strategy plans of the National program to achieve the goal of urogenital schistosomiasis elimination in seasonal foci in Senegal.

Urogenital schistosomiasis represents a serious cause of morbidity and mortality in S. haematobium endemic countries. Treatment with praziquantel (PZQ) is effective at reducing or eliminating active infection, but does not prevent reinfection that remains a continuing problem in high-risk communities, especially in areas where contacts with infested water are inevitable. The efficacy of PZQ treatment is challenged by regular re-infection in high risk communities due to frequent contact with water infested with snails carrying the larvae of S. haematobium. A large number of countries have initiated schistosomiasis control and elimination programs based on repeated PZQ mass drug administration (MDA). However, little information is available on the impact of repeated treatment on S. haematobium transmission dynamics in areas where transmission occurs seasonally in temporary water bodies. This observational study assessed the effect of annual repeated cohort treatment with PZQ over 3 years on the seasonal transmission dynamics of S. haematobium in nine villages in Niakhar district, District. Repeated annual treatments have a considerable impact on the transmission dynamics of S. haematobium in Niakhar. The prevalence of S. haematobium was dramatically reduced from 57.7% in 2011 to 10.1% in 2014. The reinfection rate did not exceed 10% from 2012 to 2014. Also, the rate of infested Bulinid snails decreased from 0.8% in 2012 to 0.5% in 2013. These results suggest that it may be possible to implement urogenital schistosomiasis elimination strategies in the Niakhar district and other seasonal transmission areas in Senegal if praziquantel MDAs are carried out in combination with other measures such as health education, improvement of access to clean water and snail control.

Efficacy and side effects of praziquantel in the treatment of Schistosomiasis mansoni in schoolchildren in Shesha Kekele Elementary School, Wondo Genet, Southern Ethiopia

OBJECTIVE

To evaluate the efficacy and side effects of praziquantel (PZQ) in the treatment of schistosomiasis in Ethiopia.

METHODS

In a cross-sectional study, stool specimens were collected from randomly selected 299 school children in Shesha Kekele Elementary School, Wondo Genet, Southern Ethiopia, in April 2010. Stool specimens were examined using a single Kato-Katz thick smear for Schistosoma mansoni (S. mansoni) ova. Children who were found positive for S. mansoni were treated with a single oral dose of PZQ at 40 mg/kg bw and interviewed for treatment-related symptoms 24 hours after drug administration. Four weeks post-treatment, stool specimens were collected from the same children and examined following the same procedure as in the pre-treatment. Drug efficacy was determined based on cure and egg reduction rates.

RESULTS

Pre-treatment prevalence of S. mansoni infection was 74.9% with geometric mean egg count of 268. The evaluated generic PZQ produced an overall cure rate of 73.6% (P<0.000 1, OR: 8.33, CI: 5.3-13.1) and egg reduction rate of 68.2% (P=0.03, F=0.64). The cure rate showed significant association with age (χ(2)=11, P=0.004), the highest rate being observed in the 15-22 age group. 83% of S. mansoni infected children showed various treatment-related symptoms, the most frequent being headache, nausea, and abdominal pain. These symptoms were associated with age (P<0.001) and pre-treatment intensity of infection (P<0.05).

CONCLUSIONS

The present observations revealed relatively lower cure and egg reduction rates of the PZQ evaluated as compared to previous reports for other PZQ brands in Ethiopia. Hence, in depth studies are recommended to clarify whether the present relatively lower cure rate is the actual cure rate of the praziquantel evaluated, treatment failure, or reduced susceptibility of the parasite. Treatment-related side effects observed were transient and tolerable.

Clinical efficacy and tolerability of praziquantel for intestinal and urinary schistosomiasis-a meta-analysis of comparative and non-comparative clinical trials

BACKGROUND

Extensive use of praziquantel for treatment and control of schistosomiasis requires a comprehensive understanding of efficacy and safety of various doses for different Schistosoma species.

METHODOLOGY/PRINCIPAL FINDINGS

A systematic review and meta-analysis of comparative and non-comparative trials of praziquantel at any dose for any Schistosoma species assessed within two months post-treatment. Of 273 studies identified, 55 were eligible (19,499 subjects treated with praziquantel, control treatment or placebo). Most studied were in school-aged children (64%), S. mansoni (58%), and the 40 mg/kg dose (56%); 68% of subjects were in Africa. Efficacy was assessed as cure rate (CR, n=17,017) and egg reduction rate (ERR, n=13,007); safety as adverse events (AE) incidence. The WHO-recommended dose of praziquantel 40 mg/kg achieved CRs of 94.7% (95%CI 92.2-98.0) for S. japonicum, 77.1% (68.4-85.1) for S. haematobium, 76.7% (95%CI 71.9-81.2) for S. mansoni, and 63.5% (95%CI 48.2-77.0) for mixed S. haematobium/S. mansoni infections. Using a random-effect meta-analysis regression model, a dose-effect for CR was found up to 40 mg/kg for S. mansoni and 30 mg/kg for S. haematobium. The mean ERR was 95% for S. japonicum, 94.1% for S. haematobium, and 86.3% for S. mansoni. No significant relationship between dose and ERR was detected. Tolerability was assessed in 40 studies (12,435 subjects). On average, 56.9% (95%CI 47.4-67.9) of the subjects receiving praziquantel 40 mg/kg experienced an AE. The incidence of AEs ranged from 2.3% for urticaria to 31.1% for abdominal pain.

CONCLUSIONS/SIGNIFICANCE

The large number of subjects allows generalizable conclusions despite the inherent limitations of aggregated-data meta-analyses. The choice of praziquantel dose of 40 mg/kg is justified as a reasonable compromise for all species and ages, although in a proportion of sites efficacy may be lower than expected and age effects could not be fully explored.

Drugs for treating urinary schistosomiasis

BACKGROUND

Urinary schistosomiasis is caused by an intravascular infection with parasitic Schistosoma haematobium worms. The adult worms typically migrate to the venous plexus of the human bladder and excrete eggs which the infected person passes in their urine. Chronic infection can cause substantial morbidity and long-term complications as the eggs become trapped in human tissues causing inflammation and fibrosis. We summarised evidence of drugs active against the infection. This is new edition of a review first published in 1997.

OBJECTIVES

To evaluate the efficacy and safety of drugs for treating urinary schistosomiasis.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register, MEDLINE, CENTRAL, EMBASE and LILACS and reference lists of articles up to 23 May 2014.

SELECTION CRITERIA

Randomized controlled trials (RCTs) of antischistosomal drugs and drug combinations compared to placebo, no intervention, or each other.

DATA COLLECTION AND ANALYSIS

Two researchers independently screened the records, extracted the data and assessed risk of bias. The primary efficacy outcomes were parasitological failure (defined as the continued presence of S. haematobium eggs in the urine at time points greater than one month after treatment), and percent reduction of egg counts from baseline. We presented dichotomous data as risk ratios (RR), and continuous data as mean difference (MD), alongside their 95% confidence intervals (CIs). Where appropriate we combined trials in meta analyses or tables. We assessed the quality of evidence using the GRADE approach.

MAIN RESULTS

We included 30 RCTs enrolling 8165 participants in this review. Twenty-four trials were conducted in children in sub-Saharan Africa, and 21 trials were over 20 years old. Many studies were assessed as being at unclear risk of bias due to inadequate descriptions of study methods. PraziquantelOn average, a single 40 mg/kg dose of praziquantel reduced the proportion of people still excreting eggs in their urine by around 60% compared to placebo at one to two months after treatment (treatment failure: RR 0.42, 95% CI 0.29 to 0.59, 864 participants, seven trials, high quality evidence). The proportion of people cured with praziquantel varied substantially between trials, from 22.5% to 83.3%, but was higher than 60% in five of the seven trials. At one to two months following praziquantel treatment at 40 mg/kg, the mean number of schistosome eggs in the urine was reduced by over 95% in five out of six trials (678 participants, six trials, high quality evidence).Splitting praziquantel 40 mg/kg into two doses over 12 hours probably has no benefits over a single dose, and in a single trial of 220 participants the split dose caused more vomiting (RR 0.5, 95% CI 0.29 to 0.86) and dizziness (RR 0.39, 95% CI 0.16 to 0.94). MetrifonateA single dose of metrifonate 10 mg/kg reduced egg excretion (210 participants, one trial, at eight months), but was only marginally better than placebo at achieving cure at one month (RR 0.83, 95% CI 0.74 to 0.94, 142 participants, one trial). In a single trial comparing one, two and three doses, the absolute number of participants cured improved from 47% after one dose to 81% after three doses (93 participants, one trial, low quality evidence).Two small trials compared 40 mg/kg single dose praziquantel with two or three doses of 10 mg/kg metrifonate and found no clear evidence of differences in cure (metrifonate 2 x 10 mg/kg at one month: RR 1.03, 95% CI 0.8 to 1.34, 72 participants, one trial; metrifonate 3 x 10 mg/kg at three months: RR 0.33, 95% CI 0.07 to 1.57, 100 participants, one trial. In one trial both drugs performed badly and in one trial both performed well. Other drugsThree trials have evaluated the antimalarial artesunate; with inconsistent results. Substantial antischistosomal effects were only seen in one of the three trials, which was at unclear risk of bias due to poor reporting of the trial methods. Similarly, another anti-malarial mefloquine has been evaluated in two small trials with inconsistent effects.Adverse events were described as mild for all evaluated drugs, but adverse event monitoring and reporting was generally of low quality.

AUTHORS' CONCLUSIONS

Praziquantel 40 mg/kg is the most studied drug for treating urinary schistosomiasis, and has the strongest evidence base.Potential strategies to improve future treatments for schistosomiasis include the combination of praziquantel with metrifonate, or with antimalarial drugs with antischistosomal properties such as artesunate and mefloquine. Evaluation of these combinations requires rigorous, adequately powered trials using standardized outcome measures.

Effectiveness of a pre-treatment snack on the uptake of mass treatment for schistosomiasis in Uganda: a cluster randomized trial

BACKGROUND

School-based mass treatment with praziquantel is the cornerstone for schistosomiasis control in school-aged children. However, uptake of treatment among school-age children in Uganda is low in some areas. The objective of the study was to examine the effectiveness of a pre-treatment snack on uptake of mass treatment.

METHODS AND FINDINGS

In a cluster randomized trial carried out in Jinja district, Uganda, 12 primary schools were randomized into two groups; one received education messages for schistosomiasis prevention for two months prior to mass treatment, while the other, in addition to the education messages, received a pre-treatment snack shortly before mass treatment. Four weeks after mass treatment, uptake of praziquantel was assessed among a random sample of 595 children in the snack schools and 689 children in the non-snack schools as the primary outcome. The occurrence of side effects and the prevalence and mean intensity of Schistosoma mansoni infection were determined as the secondary outcomes. Uptake of praziquantel was higher in the snack schools, 93.9% (95% CI 91.7%-95.7%), compared to that in the non-snack schools, 78.7% (95% CI 75.4%-81.7%) (p = 0.002). The occurrence of side effects was lower in the snack schools, 34.4% (95% CI 31.5%-39.8%), compared to that in the non-snack schools, 46.9% (95% CI 42.2%-50.7%) (p = 0.041). Prevalence and mean intensity of S. mansoni infection was lower in the snack schools, 1.3% (95% CI 0.6%-2.6%) and 38.3 eggs per gram of stool (epg) (95% CI 21.8-67.2), compared to that in the non-snack schools, 14.1% (95% CI 11.6%-16.9%) (p = 0.001) and 78.4 epg (95% CI 60.6-101.5) (p = 0.001), respectively.

CONCLUSIONS

Our results suggest that provision of a pre-treatment snack combined with education messages achieves a higher uptake compared to the education messages alone. The use a pre-treatment snack was associated with reduced side effects as well as decreased prevalence and intensity of S. mansoni infection.

TRIAL REGISTRATION

www.ClinicalTrials.gov NCT01869465

Increasing teacher motivation and supervision is an important but not sufficient strategy for improving praziquantel uptake in Schistosoma mansoni control programs: serial cross sectional surveys in Uganda

BACKGROUND

Realization of the public health benefits of mass drug administration (MDA) for the control of schistosomiasis depends on achieving and maintaining high annual treatment coverage. In Uganda, the uptake of preventive treatment for schistosomiasis among school-age children in 2011 was only 28%. Strategies are needed to increase uptake.

METHODS

Serial cross-sectional surveys were conducted at baseline (after MDA in 2011) and at follow-up MDA in 2012 where teacher motivation was provided and supervision strengthened in Jinja district of Uganda. Uptake of praziquantel was assessed in 1,010 randomly selected children from 12 primary schools during the baseline survey and in another set of 1,020 randomly selected children from the same primary schools during the follow-up survey.

RESULTS

Self-reported uptake of praziquantel increased from 28.2% (95% CI 25.4%-30.9%) at baseline to 48.9% (95% CI 45.8%-52.0%) (p < 0.001) at follow-up. Prevalence and intensity of Schistosoma mansoni infection were unchanged and moderate on both occasions; 35.0% (95% CI: 25.4%-37.9%) and 32.6% (95% CI: 29.6%-35.5%) (p = 0.25) and 156.7 eggs per gram of stool (epg) (95% CI: 116.9-196.5) and 133.1 epg (95% CI: 99.0-167.2) (p = 0.38), respectively. There was no change in the proportion of children reporting side effects attributable to praziquantel at baseline (49.8%, 95% CI 43.8%-55.8%) and at follow-up (46.6%, 95% CI 42%.1-51.2%) (p = 0.50) as well as in the proportion of children with correct knowledge of schistosomiasis transmission and control between the baseline (45.9%, 95% CI 42.7%-73.7%) and follow-up (44.1%, 95% CI 41.0%- 47.2%) (p = 0.42).

CONCLUSION

Although teacher motivation and supervision to distribute treatment increased the uptake of praziquantel among school-age children, the realized uptake is still lower than is recommended by the World Health Organization (WHO) and apparently too low to affect the prevalence and intensity of schistosomiasis among the children. Additional measures are needed to increase uptake of praziquantel if school-based MDA is to achieve the objective of preventive chemotherapy.

Efficacy of Praziquantel against Schistosoma haematobium in Dulshatalo village, western Ethiopia

Background

Praziquantel (PZQ) is the drug of choice for treatment of all human schistosomes. It is used in population based targeted or mass deworming strategies in several countries. The effect of PZQ on S. hematobium has not been studied in Ethiopia. The objective of this study was to determine the efficacy of PZQ against S. haematobium in Dulshatalo village, western Ethiopia.

Methods

A prospective study was conducted from October to December, 2007. Urine samples from 341 residents were collected and screened for haematuria and proteinuria using urinalysis dipstick. S. haematobium eggs were detected and quantified using filtration techniques. The participants who were positive for haematuria were treated with a standard dose of PZQ (40 mg/kg). Data on pre and 24 hours post treatment symptoms were collected via questionnaire. Urine samples were also collected 7 weeks after treatment and examined to assess the cure and the egg reduction rates.

Results

The prevalence of S. haematobium among the study participants was 57.8% (197/341). Haematuria was detected in 234 (68.6%) of the study participants. For PZQ efficacy asessment, 152 of the treated participants were considered. The presence of S. haemetaobium eggs showed statistically significant association (p < 0.05) with haematuria and proteinuria. Seven weeks post treatment, the extent of haematuria and proteinuria decreased from 100% to 40.8% and 94.07% to 48.7%, respectively. The cure and the parasitological egg reduction rates seven weeks post treatment were 86% and 85%, respectively. Post treatment symptoms revealed a wide range of side effects including straining, abdominal pain, nausea and headache.

Conclusions

There were marked cure and egg reduction rates, together with mild and short lived side effects of PZQ for treatment of S. haematobium, in this study.

Efficacy of artesunate in the treatment of urinary schistosomiasis, in an endemic community in Nigeria

The efficacy and tolerability of oral artesunate for the treatment of urinary schistosomiasis was assessed among schoolchildren aged 5-18 years in Adim community, Nigeria. Overall, 500 children, randomly selected from those attending the Presbyterian primary school, were each invited to provide two consecutive urine samples. Using standard parasitological procedures, Schistosoma haematobium ova were found in the samples from 145 (29.0%) of the subjects. Most (87) of the infected subjects were then treated orally with artesunate, using two doses, each of 6 mg/kg, given 2 weeks apart. When the treated children were re-examined 4 weeks after the second dose of artesunate, 61 (70.1%) appeared egg-negative and were therefore considered cured. Post-treatment, the geometric mean egg count (GMEC) for the treated subjects who were not cured was significantly lower than the pre-treatment GMEC for all the treated subjects, with log10[(eggs/10 ml urine) + 1] values of 0.9 v. 1.75 (t = 4.45; P < 0.05). The cure 'rate' for the subjects aged > or = 10 years was slightly higher than that among the younger subjects. It was lowest for the heavier subjects (70% for those weighing 41-50 kg) and highest (79%) for the subjects who weighed 31-40 kg. The artesunate was well tolerated. This observation of a therapeutic effect of artesunate against S. haematobium in Nigeria confirms recent observations from Senegal. In the Adim community at least, it would be more cost-effective to treat urinary schistosomiasis with artesunate than with praziquantel. The wide-spread use of artesunate against schistosomiasis has to be considered carefully, however, if it is not to compromise the efficacy of the drug as an antimalarial, by increasing the risk of resistance developing in local Plasmodium.

The role of artesunate for the treatment of urinary schistosomiasis in schoolchildren: a systematic review and meta-analysis

OBJECTIVE

Efficacy of artemisinin derivatives alone or in combination compared to praziquantel alone for the treatment of urinary schistosomiasis in schoolchildren.

METHODS

Randomized clinical trials comparing praziquantel with artemisinin derivatives in the treatment of urinary schistosomiasis in schoolchildren were included. Medline, EMBASE, LILACS, CENTRAL, African Index Medicus, and Scielo were searched. We also analyzed the abstracts of the main conferences on infectious diseases and tropical medicine during the years 2009-2011. Google Scholar and OpenSIGLE were also searched. The last search was performed in July 2012. The primary endpoint was the cure rate. The main outcome data were retrieved using a standardized form; three independent researchers (WP, HC, and SS) performed the search, retrieved data, and evaluated the risk of bias. Disagreements were resolved by discussion. Risk ratios were used and heterogeneity was evaluated. A fixed or random-effects model was used according to the results of heterogeneity testing. An intention-to-treat analysis was done. Data were analyzed using Revman 5·0·24 (Copenhagen: The Nordic Cochrane Centre).

RESULTS

Seven studies were selected for full text review and only five studies were finally included. The cure rate for praziquantel was superior to that of artesunate (RR: 1·66; 95% CI: 1·18-2·33). Artesunate was not clearly superior to placebo (artesunate versus placebo, RR: 3·21; 95% CI: 0·50-20·74). Combination of artesunate with praziquantel could prove more beneficial than praziquantel alone (RR: 1·15; 95% CI: 1·01-1·31). The frequency of adverse events was equivalent for both drugs (praziquantel versus artesunate, RR: 1·11; 95% CI: 0·80-1·55).

CONCLUSIONS

Our meta-analysis showed that praziquantel was significantly more effective than artesunate for the treatment of urinary schistosomiasis in schoolchildren. Artesunate at best had a marginal role in combination therapy.

Drugs for treating Schistosoma mansoni infection

BACKGROUND

Schistosoma mansoni is a parasitic infection common in the tropics and sub-tropics. Chronic and advanced disease includes abdominal pain, diarrhoea, blood in the stool, liver cirrhosis, portal hypertension, and premature death.

OBJECTIVES

To evaluate the effects of antischistosomal drugs, used alone or in combination, for treating S. mansoni infection.

SEARCH METHODS

We searched MEDLINE, EMBASE and LILACS from inception to October 2012, with no language restrictions. We also searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (The Cochrane Library 2012) and mRCT. The reference lists of articles were reviewed and experts were contacted for unpublished studies.

SELECTION CRITERIA

Randomized controlled trials of antischistosomal drugs, used alone or in combination, versus placebo, different antischistosomal drugs, or different doses of the same antischistosomal drug for treating S. mansoni infection.

DATA COLLECTION AND ANALYSIS

One author extracted data and assessed eligibility and risk of bias in the included studies, which were independently checked by a second author. We combined dichotomous outcomes using risk ratio (RR) and continuous data weighted mean difference (WMD); we presented both with 95% confidence intervals (CI). We assessed the quality of evidence using the GRADE approach.

MAIN RESULTS

Fifty-two trials enrolling 10,269 participants were included. The evidence was of moderate or low quality due to the trial methods and small numbers of included participants.Praziquantel: Compared to placebo, praziquantel 40 mg/kg probably reduces parasitological treatment failure at one month post-treatment (RR 3.13, 95% CI 1.03 to 9.53, two trials, 414 participants, moderate quality evidence). Compared to this standard dose, lower doses may be inferior (30 mg/kg: RR 1.52, 95% CI 1.15 to 2.01, three trials, 521 participants, low quality evidence; 20 mg/kg: RR 2.23, 95% CI 1.64 to 3.02, two trials, 341 participants, low quality evidence); and higher doses, up to 60 mg/kg, do not appear to show any advantage (four trials, 783 participants, moderate quality evidence).The absolute parasitological cure rate at one month with praziquantel 40 mg/kg varied substantially across studies, ranging from 52% in Senegal in 1993 to 92% in Brazil in 2006/2007. Oxamniquine: Compared to placebo, oxamniquine 40 mg/kg probably reduces parasitological treatment failure at three months (RR 8.74, 95% CI 3.74 to 20.43, two trials, 82 participants, moderate quality evidence). Lower doses than 40 mg/kg may be inferior at one month (30 mg/kg: RR 1.78, 95% CI 1.15 to 2.75, four trials, 268 participants, low quality evidence; 20 mg/kg: RR 3.78, 95% CI 2.05 to 6.99, two trials, 190 participants, low quality evidence), and higher doses, such as 60 mg/kg, do not show a consistent benefit (four trials, 317 participants, low quality evidence).These trials are now over 20 years old and only limited information was provided on the study designs and methods. Praziquantel versus oxamniquine: Only one small study directly compared praziquantel 40 mg/kg with oxamniquine 40 mg/kg and we are uncertain which treatment is more effective in reducing parasitological failure (one trial, 33 participants, very low quality evidence). A further 10 trials compared oxamniquine at 20, 30 and 60 mg/kg with praziquantel 40 mg/kg and did not show any marked differences in failure rate or percent egg reduction.Combination treatments: We are uncertain whether combining praziquantel with artesunate reduces failures compared to praziquantel alone at one month (one trial, 75 participants, very low quality evidence).Two trials also compared combinations of praziquantel and oxamniquine in different doses, but did not find statistically significant differences in failure (two trials, 87 participants). Other outcomes and analyses: In trials reporting clinical improvement evaluating lower doses (20 mg/kg and 30 mg/kg) against the standard 40 mg/kg for both praziquantel or oxamniquine, no dose effect was demonstrable in resolving abdominal pain, diarrhoea, blood in stool, hepatomegaly, and splenomegaly (follow up at one, three, six, 12, and 24 months; three trials, 655 participants).Adverse events were not well-reported but were mostly described as minor and transient.In an additional analysis of treatment failure in the treatment arm of individual studies stratified by age, failure rates with 40 mg/kg of both praziquantel and oxamniquine were higher in children.

AUTHORS' CONCLUSIONS

Praziquantel 40 mg/kg as the standard treatment for S. mansoni infection is consistent with the evidence. Oxamniquine, a largely discarded alternative, also appears effective.Further research will help find the optimal dosing regimen of both these drugs in children.Combination therapy, ideally with drugs with unrelated mechanisms of action and targeting the different developmental stages of the schistosomes in the human host should be pursued as an area for future research.

Systematic review and meta-analysis of artemisinin based therapies for the treatment and prevention of schistosomiasis

BACKGROUND

Chemotherapy based on repeated doses of praziquantel is still the most effective control strategy against Schistosomiasis, however artemisinin derivatives emerged as a family of compounds with schistomicide activity. The aim of the present work is to compare the efficacy of artemisinin-based therapies in the treatment and prophylaxis of human schistosomiasis. The design of this work involved a quantitative systematic review and meta-analysis.

METHODOLOGY/PRINCIPAL FINDINGS

Retrieval of published studies was carried out through an electronic search of the PubMed (MEDLINE), EMBASE, Cochrane Library and CINAHL databases. This included reports comparing the therapeutic efficacy of artesunate alone, artesunate plus sulfadoxine-pyrimethamine and a combination of artemisinin derivatives plus praziquantel against praziquantel alone on different types of schistosomiasis. Moreover, studies on artesunate and artemether used as preventive drugs were also analyzed against placebo. The primary outcome measure for schistosomiasis treatment was "parasitological cure", whereas for the prophylaxis the outcome evaluated was "infection rate". Our results show that patients treated with artesunate alone have significantly lower cure rates than those treated with praziquantel (OR = 0.27 (95% C.I. 0.13-0.53; p<0.001)) and that the combined therapy of artesunate plus sulfadoxine-pyrimethamine is also significantly less effective than praziquantel treatment (OR = 0.14 (95% C.I. 0.02-0.92; p = 0.04)). However, the combination of an artemisinin derivatives plus praziquantel showed a higher cure rate than praziquantel monotherapy with OR = 2.07 (95% C.I. 1.27-3.36; p = 0.003). Finally, chemoprophylaxis with either artesunate (RR = 0.11 (95% C.I. 0.06-0.22; p<0.001)) or artemether (RR = 0.25 (95% C.I. 0.16-0.40; p<0.001)) was significantly better than a placebo in both cases.

CONCLUSIONS/SIGNIFICANCE

This meta-analysis confirms that artemisinin derivatives used in combination with praziquantel have the potential to increase the cure rates in schistosomiasis treatment, but not artesunate alone. It is also confirmed that repeated doses of artemisinin derivatives play a prophylactic role, significantly reducing the incidence of Schistosoma japonicum infections compared with placebo.

Schistosoma haematobium treatment in 1-5 year old children: safety and efficacy of the antihelminthic drug praziquantel

Background

Morbidity due to schistosomiasis is currently controlled by treatment of schistosome infected people with the antihelminthic drug praziquantel (PZQ). Children aged up to 5 years are currently excluded from schistosome control programmes largely due to the lack of PZQ safety data in this age group. This study investigated the safety and efficacy of PZQ treatment in such children.

Methods

Zimbabwean children aged 1–5 years (n = 104) were treated with PZQ tablets and side effects were assessed by questionnaire administered to their caregivers within 24 hours of taking PZQ. Treatment efficacy was determined 6 weeks after PZQ administration through schistosome egg counts in urine. The change in infection levels in the children 1–5 years old (n = 100) was compared to that in 6–10 year old children (n = 435).

Principal Findings

Pre-treatment S. haematobium infection intensity in 1–5 year olds was 14.6 eggs/10 ml urine and prevalence was 21%. Of the 104 children, 3.8% reported side effects within 24 hours of taking PZQ treatment. These were stomach ache, loss of appetite, lethargy and inflammation of the face and body. PZQ treatment significantly reduced schistosome infection levels in 1–5 year olds with an egg reduction rate (ERR) of 99% and cure rate (CR) of 92%. This was comparable to the efficacy of praziquantel in 6–10 year olds where ERR was 96% and CR was 67%.

Interpretation/Significance

PZQ treatment is as safe and efficacious in children aged 1–5 years as it is in older children aged 6–10 years in whom PZQ is the drug of choice for control of schistosome infections.

Urogenital schistosomiasis is an important, but neglected, infectious disease affecting over 100 million people, mainly in Africa. Children carry the heaviest burden of infection with children as young as 1 year old showing signs of infection. Children aged 5 years and below are currently excluded from schistosome control programmes for several reasons, including operational difficulties associated with accessing preschool children, misconceptions about their level of exposure to infective water and lack of safety data on the drug of choice for schistosome control, praziquantel, in children aged 5 years and below. This study was one of a small number of studies recently funded by the World Health Organization to investigate the need for praziquantel treatment in preschool children (aged 1–5 years) and to subsequently assess the safety and efficacy of the drug praziquantel in this age group. This study confirmed that preschool children carry significant levels of schistosome infection, exceeding those carried by their parents/guardians, highlighting the urgent need for their immediate inclusion in schistosome control programmes. The study also showed that praziquantel treatment is as safe and efficacious in children aged 1–5 years as it is in older children aged 6–10 years who are currently the target for mass drug administration.

Efficacy of artesunate + sulfamethoxypyrazine/pyrimethamine versus praziquantel in the treatment of Schistosoma haematobium in children

Background

This study was conducted to determine the efficacy of the antimalarial artemisinin-based combination therapy (ACT) artesunate +sulfamethoxypyrazine/pyrimethamine (As+SMP), administered in doses used for malaria, to treat Schistosoma haematobium in school aged children.

Methodology/Principal Findings

The study was conducted in Djalakorodji, a peri-urban area of Bamako, Mali, using a double blind setup in which As+SMP was compared with praziquantel (PZQ). Urine samples were examined for Schistosoma haematobium on days −1, 0, 28 and 29. Detection of haematuria, and haematological and biochemical exams were conducted on day 0 and day 28. Clinical exams were performed on days 0, 1, 2, and 28. A total of 800 children were included in the trial. The cure rate obtained without viability testing was 43.9% in the As+SMP group versus 53% in the PZQ group (Chi² = 6.44, p = 0.011). Egg reduction rates were 95.6% with PZQ in comparison with 92.8% with As+SMP, p = 0.096. The proportion of participants who experienced adverse events related to the medication was 0.5% (2/400) in As+SMP treated children compared to 2.3% (9/399) in the PZQ group (p = 0.033). Abdominal pain and vomiting were the most frequent adverse events in both treatment arms. All adverse events were categorized as mild.

Conclusions/Significance

The study demonstrates that PZQ was more effective than As+SMP for treating Schistosoma haematobium. However, the safety and tolerability profile of As+SMP was similar to that seen with PZQ. Our findings suggest that further investigations seem justifiable to determine the dose/efficacy/safety pattern of As+SMP in the treatment of Schistosoma infections.

Trial Registration

ClinicalTrials.gov NCT00510159

A wake up call for urinary schistosomiasis: reconciling research effort with public health importance

This review considers the current status of urinary schistosomiasis, caused by infection with Schistosoma haematobium, and argues that greater research effort and focus are needed to improve understanding of this neglected tropical disease (NTD). The inappropriateness of relying solely on data concerning the much more extensively studied intestinal form of schistosomiasis caused by S. mansoni is highlighted. The current lack of genome and transcriptome information for S. haematobium is directly hindering further targeted research and must be quickly rectified. Recent molecular phylogenies caution the expectation of similarities between schistosome species and highlight the close relationships of species within the S. haematobium group. Treatment, current and prospective drugs and vaccines, together with diagnosis are considered, highlighting the differences associated with urinary schistosomiasis. This infection has a significant and specific impact on the urino-genital system and has a strong association with bladder cancer, leading to severe and chronic morbidity. There is a clear need for new clinical initiatives in this area to better quantify the disease burden. Furthermore, emerging associations with HIV and other pathogens need to be closely monitored. Research is urgently needed to improve current knowledge in order to develop the next generation of control tools.

Treatment of urinary schistosomiasis: methodological issues and research needs identified through a Cochrane systematic review

Guidelines recommend praziquantel (PZQ) for the treatment and control of schistosomiasis, with no real alternative. Metrifonate was still widely used against Schistosoma haematobium in the 1990s, and then withdrawn. Experimental studies and clinical trials suggest that artemisinin compounds are active against S. haematobium. In a Cochrane systematic review assessing the efficacy and safety of drugs for treating urinary schistosomiasis, 24 randomized controlled trials (n=6315 individuals) met our inclusion criteria. These trials compared a variety of single agent and combination regimens with PZQ, metrifonate or artemisinin derivatives. The review confirmed that both the standard recommended doses of PZQ (single 40 mg/kg oral dose) and metrifonate (3x7.5-10 mg/kg oral doses administered fortnightly) are efficacious and safe in treating urinary schistosomiasis, but there is no study comparing these two regimens head-to-head. There is currently not enough evidence to evaluate artemisinin compounds. Most of the studies included in the Cochrane systematic review were insufficiently powered, lacked standardization in assessing and reporting outcomes, and had a number of methodological limitations. In this paper we discuss the implications of these findings with respect to public health and research methodology and propose priority research needs.

In vitro effects of artesunate on the survival of worm pairs and egg production of Schistosoma mansoni

The effect of artesunate (ART) on the survival time of adult worm pairs of Schistosoma mansoni and on their egg output during in vitro culture was assessed. ART significantly decreased the survival time of both paired male and female worms at concentrations of 5, 10, 20 and 40 mg l− 1 during in vitro cultivation. An inhibitory effect of ART on the daily egg output of paired female worms during in vitro cultivation was also observed.

Efficacy of a combination of praziquantel and artesunate in the treatment of urinary schistosomiasis in Nigeria

The combined effects of praziquantel and artesunate in the treatment of urinary schistosomiasis were assessed among 312 randomly selected schoolchildren aged 4-20 years in Adim community, Nigeria. In the preliminary screening, infection was confirmed in 327 (38.5%) of the 850 subjects screened. Infected subjects who reported for treatment were then divided into six treatment groups of 52 subjects each; 44 subjects in each group completed their treatment regimens and submitted their urine for post-treatment assessment. Praziquantel and artesunate were administered orally at 40 mg/kg and 4 mg/kg body weight, respectively. Adverse effects due to drug reactions were assessed 72 h after medication and all perceived episodes of illness were treated. Morbidity indicators were assessed 56 days after the final dose of the drug regimens. All treatment regimens were well tolerated. The cure rates were 72.7% in the praziquantel plus placebo-treated group and 70.5% in the artesunate plus placebo group, while the artesunate plus praziquantel group had the highest cure rate (88.6%). Haematuria and proteinuria were extensively reduced after treatment with the three drug regimens. This study confirmed that the treatment of urinary schistosomiasis with the combination of praziquantel and artesunate is safe and more effective than treatment with either drug alone.

Efficacy and side effects of praziquantel treatment against Schistosoma haematobium infection among primary school children in Zimbabwe

We examined the efficacy of praziquantel against Schistosoma haematobium among primary school children during a school-based deworming programme in the Burma Valley commercial farming area and the Nyamaropa rural areas in Zimbabwe, where the disease is highly endemic. Among 767 individuals infected with S. haematobium, 675 (88.0%) received treatment. Two single oral doses of 40mg/kg praziquantel were given 6 weeks apart. Of the 675 participants, heavy infection intensity was more common in males than females (chi(2)=6.61, P=0.010). Six weeks later, 624 participants (92.4%) were successfully followed up. The overall cure rate was 88.5% and the egg reduction rate was 98.2%. The highest cure rate was among those individuals with light infection. Seventy-two individuals remained infected at 6 weeks post treatment, among which 3 and 69 individuals had heavy and light infection, respectively. Forty-six of these children resolved following a second round of treatment at 6 weeks follow-up. Of the remaining children successfully followed-up, 22 resolved after a third round of treatment 6 months later. A wide range of observed mild and transient side effects were not associated with egg intensity. The parasitological cure rate was not associated with gender or age. Our study demonstrates that praziquantel is efficacious against S. haematobium in Zimbabwe, although low levels of persistent infection warrant further investigation.

Drugs for treating urinary schistosomiasis

BACKGROUND

Urinary schistosomiasis causes long-term ill-health. This review examines the various treatment options and newer drugs.

OBJECTIVES

To evaluate antischistosomal drugs, used alone or in combination, for treating urinary schistosomiasis.

SEARCH STRATEGY

In August 2007, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (The Cochrane Library 2007, Issue 3), MEDLINE, EMBASE, LILACS, mRCT, and reference lists of articles. We also contacted experts in schistosomiasis research.

SELECTION CRITERIA

Randomized and quasi-randomized controlled trials of praziquantel, metrifonate, artemisinin derivatives, or albendazole, alone or in combination, versus placebo, different doses, or other antischistosomal drugs for treating urinary schistosomiasis.

DATA COLLECTION AND ANALYSIS

One author extracted data, and assessed eligibility and methodological quality, which were cross-checked by a second person. Dichotomous outcomes were combined using risk ratio (RR), and continuous data were combined using weighted mean difference (WMD); both presented with 95% confidence intervals (CI).

MAIN RESULTS

Twenty-four trials (6315 participants) met the inclusion criteria. Compared with placebo, participants receiving metrifonate had fewer parasitological failures at follow up at one to three months (1 trial) and three to 12 months (3 trials). Egg reduction rate was over 90%, and no adverse events were reported (1 trial). One metrifonate dose was inferior to three doses given fortnightly (both used 10 mg/kg). Praziquantel (standard single 40 mg/kg oral dose) was more effective than placebo at reducing parasitological failure at one to three months' follow up and three to 12 months. Egg reduction rates were improved with praziquantel (over 95% versus 5.3% to 64% with placebo). Mild to moderate adverse events were recorded in two trials. A comparison of metrifonate (10 mg/kg x 3, once every 4 months for one year) with praziquantel (standard dose) showed little difference in parasitological failure. For praziquantel, there was no significant difference in effect between 20 mg/kg x 2, 30 mg/kg x 1, and 20 mg/kg x 1, and the standard dose for all outcomes. One small trial of artesunate showed no obvious benefit compared with placebo, and the artesunate-praziquantel combination was similar to praziquantel alone.

AUTHORS' CONCLUSIONS

Praziquantel and metrifonate are effective treatments for urinary schistosomiasis and have few adverse events. Metrifonate requires multiple administrations and is therefore operationally less convenient in community-based control programmes. Evidence on the artemisinin derivatives is currently inconclusive, and further research is warranted on combination therapies. We suggest metrifonate be reconsidered for the WHO Model List of Essential Medicines.

Sociocultural aspects of mass delivery of praziquantel in schistosomiasis control: the Abeokuta experience

BACKGROUND

Schistosomiasis is a public health problem in Nigeria. Although there is an ongoing national program for its control, disease control programs in other countries have shown the need to understand the sociocultural aspects of disease transmission, prevention, and treatment in endemic communities before control efforts are undertaken.

OBJECTIVE

To describe sociocultural factors that influence the distribution process of praziquantel for the mass treatment of schistosomiasis infection.

METHODS

Data for the study were collected through focus group discussions held separately with adult males and females, male and female adolescents (13-19 years), and male and female children (5-12 years). In-depth interviews were similarly held with the drug distributors of praziquantel for mass treatment and with community/opinion leaders of six hyperendemic communities in Ogun State, Southwest Nigeria on mass treatment using praziquantel. These focus group discussions and in-depth interviews were held both before and following the drug distribution. The data were analyzed using the textual analysis program, Textbase Beta.

RESULTS

Following a 3-week period of mass treatment in six communities, we observed an increased awareness of rivers/streams as a source of schistosomiasis. In addition, the communities reported overwhelming support for the mass treatment after receiving treatment. The reasons for this acceptance appear to include the perceived efficacy of praziquantel against the disease and its availability free of charge. The drug's distributors adhered to the originally specified systems-based protocol for mass treatment in only two of the six communities. The systems-based protocol adhered to strict distribution through primary health centers and schools. The four other communities used a community-based approach for mass treatment with praziquantel and attained greater coverage of treatment as a result.

CONCLUSION

Obtaining community support and involvement before the implementation of mass treatment of schistosomiasis with praziquantel contributes to an effective treatment strategy for this disease. A detailed assessment of a community's health needs, before the initiation of the control efforts against endemic infections, should be undertaken.

Antischistosomal efficacy of artesunate combination therapies administered as curative treatments for malaria attacks

Artesunate is a highly effective antimalarial and there is some evidence that it is also active against schistosome infections. We therefore investigated whether treatment with artesunate of acute malaria in Senegalese children had an impact on their level of infection with Schistosoma haematobium. Twenty-seven children who were entered into a clinical trial of antimalaria treatment were excreting S. haematobium eggs in their urine on the day of treatment. Fifteen children received a combination of a single dose of sulfadoxine/pyrimethamine together with three daily doses of artesunate (4 mg/kg); the remaining 12 children received three daily doses of amodiaquine and artesunate. The overall cure rate and reduction in the mean number of excreted eggs at 28 days post treatment were 92.6% and 94.5%, respectively. Our findings indicate that artesunate, in addition to being a very effective treatment for uncomplicated malaria, can also sharply reduce the S. haematobium loads harboured by pre-school African children.

Implementation of Human Schistosomiasis Control: Challenges and Prospects

Schistosomiasis is a major disease of public health importance in humans occurring in over 70 countries of the tropics and sub-tropics. In this chapter, the history of the control of schistosomiasis is briefly discussed and current methods of control of schistosomiasis are reviewed; including mollusciciding, biological control of the intermediate snail hosts, the development of drugs to kill the adult worms, provision of clean water and health education, with a focus on the African situation. Since an effective vaccine against schistosomiasis is lacking, the emphasis today is placed on the drug praziquantel (PZQ). The marked reduction in the cost of PZQ together with the support of the Bill and Melinda Gates Foundation has enabled the drug to be used more widely in sub-Saharan Africa. Nevertheless, with the possibility of resistance to praziquantel emerging, the potential role of other drugs, such as artemether, in the control of schistosomiasis is examined. The World Health Organization (WHO) anticipates that at least 75% of all schoolchildren at risk of morbidity from schistosomiasis will be treated by 2010, with the aim of reversing morbidity. The importance of recent international initiatives such as the Schistosomiasis Control Initiative (SCI) working in Mali, Niger, Burkina Faso, Zambia, Tanzania and Uganda is recognised. There are benefits to integrating the control of schistosomiasis with other disease control programmes, such as gastrointestinal helminths and/or lymphatic filariasis (LF), since this markedly reduces the cost of delivery of the treatment. Countries that are situated on the perimeter of the distribution of schistosomiasis have either achieved or have made progress towards the elimination of the disease. For control programmes to be successful in areas such as sub-Saharan Africa, it is absolutely essential that these programmes are sustainable. Thus, it will be vital for Ministries of Health and Education to budget for the control of diseases of poverty in addition to school health, and to utilise funds from a range of sources, such as, government funds, pooled donor contributions, or bilateral and international agencies.

A double-blind field trial on the effects of artemether on Schistosoma japonicum infection in a highly endemic focus in southern China

To further strengthen the evidence-base of artemether for the control of schistosomiasis japonica, a randomised controlled trial was carried out in the Poyang Lake region, a highly endemic area in southern China. A total of 783 individuals, aged 6-60 years, were enrolled. They were first given a single oral dose of praziquantel (50 mg/kg). Then, they were randomly assigned oral artemether (6 mg/kg) or placebo, administered once every 2 weeks for 9-11 doses, covering the entire transmission season for Schistosoma japonicum in 2004. Stool examination 1 month after the final dosing revealed eggs of S. japonicum in 3/373 (0.8%) of the artemether recipients and 56/361 (15.0%) in placebo recipients (chi2=53.69, P<0.001). Compared to the baseline, the geometric mean intensity of S. japonicum infection had decreased by 96.1% in the artemether group, and increased by 50.8% in the placebo group. No acute cases of schistosomiasis japonica were observed in the artemether group, whereas three such cases were reported from the placebo group. Compliance with regard to multi-doses of artemether and placebo was 84.9, and 77.9%, respectively. This study confirms that repeated oral artemether produces no drug-related adverse effects, significantly reduces incidence and intensity of patent S. japonicum infection and results in high compliance. Hence it can be used as an additional tool for the control of schistosomiasis japonica in the lake regions of China.

Development of antischistosomal drugs in China, with particular consideration to praziquantel and the artemisinins

Remarkable achievements have been made in the control of schistosomiasis in China, with chemotherapy playing a seminal role. From the early 1950s through the early 1980s, Chinese scientists made considerable progress in discovery and development of compounds with antischistosomal properties, including antimonials, non-antimonials and various effective principles stemming from traditional herbs. However, only few compounds entered clinical testing, while others were abandoned mainly due to their toxicity and poor efficacy. The advent of praziquantel in the 1970s changed the landscape of research and development of drugs for treatment and morbidity control of schistosomiasis. The main Chinese contributions to enhance the understanding of the antischistosomal drug praziquantel are reviewed here, including issues of metabolism, antibody-dependency, host immune factors, stage-specific susceptibility and resistance. Over the past 25 years, researchers from China successfully developed artemether and artesunate, two derivatives from the antimalarial artemisinin, as promising drugs against Schistosoma japonicum. Laboratory investigations showed that the artemisinins display their highest activity against the juvenile stages of the parasite. These findings were consistently confirmed in randomised controlled trials; repeated oral administration of artemether or artesunate was safe and efficacious in the prevention of patent S. japonicum infections. The key findings are reviewed here, and emphasis is placed on how it stimulated research outside of China on other human schistosome species.

Therapeutic failure of praziquantel in the treatment of Schistosoma haematobium infection in Brazilians returning from Africa

Several cases of therapeutic failure of praziquantel used for the treatment of urinary schistosomiasis have been reported. Alternative drugs, like niridazol and metrifonate, have shown a lower therapeutic effect and more side effects than praziquantel. Twenty-six Brazilian military men (median age of 29 years) with a positive urine parasitological exam who were part of a United Nation peace mission in Mozambique in 1994 were treated with 40 mg/kg body weight praziquantel, single dose. They swam in Licungo river (Mocuba city, Mozambique) during the weekends. After this, they presented haematuria, dysuria, polakiuria, and lumbar pain. Control cystoscopy examinations carried out between 6 and 24 months after each treatment (including two additional treatments at a minimum interval of 6 months) revealed the presence of viable eggs. Granulomas in the vesical submucosa were observed in 46.2% (12/26) of the individuals. A vesical biopsy confirmed the presence of granulomas in all of these patients and the presence of viable eggs in 34.3% (9/26) of individuals who no longer excreted eggs in urine. The eggs filled with miracidia showed characteristics of viability. Histopathological examination using different strains demonstrated therapeutic failure and the need for repeated treatment. In this study, we demonstrated a low efficacy of praziquantel in the treatment of schistosomiasis haematobia, and the necessity of the urinary bladder biopsy as criterion of cure.

Effectiveness of different approaches to mass delivery of praziquantel among school-aged children in rural communities in Nigeria

Schistosomiasis is hyperendemic in Nigeria. The national policy on schistosomiasis control has adopted praziquantel as the main drug of use in the control strategy aimed at reducing morbidity. However, the best delivery channel for praziquantel in schistosomiasis control in Nigeria is yet to be determined. This study assessed different channels for praziquantel delivery in a mass treatment effort. Three groups, each of two communities, were assigned to one of the following three channels: health facility (HF), school, and community for mass delivery of praziquantel to school-aged children. Distributors were trained on all aspects of praziquantel distribution and sufficient praziquantel tablets were provided for the drug distribution within 3 weeks following which an evaluation of the drug distribution by the different treatment channels was conducted. Overall, the community channel of delivery achieved the best coverage of 72.2% (range: 69-73%) compared to 44.3% (range: 39.5-62%) and 28.5% (range: 26.3-74.5%) for the HF and school channels, respectively. Community channel of praziquantel delivery as shown in this study ensures good coverage of both in and out-of-school children.

Schistosomiasis control: keep taking the tablets

Despite the limited reports of praziquantel resistance, the relative success of chemotherapy-based control programmes for schistosomiasis has prompted overdue efforts to expand the use of cheap, generic, praziquantel in sub-Saharan Africa. The likely impact of such programmes on the development and spread of praziquantel resistance is uncertain, but this possibility reinforces the need for monitoring the spectrum of praziquantel sensitivity of schistosome populations and for an improved knowledge of the precise targets for the action of the drug. The search for alternatives to praziquantel and other tools for control of schistosomiasis must continue.

Schistosomiasis vaccines

While there are many challenges in vaccine development, none is greater than that of developing vaccines against large metazoan parasites such as schistosomes, the parasitic worms that are responsible for schistosomiasis. Initial optimism stemming from the identification of the first vaccine candidate antigens that gave protection in animals has been dashed by the failure, as yet, of any of the vaccine candidate antigens to enter Phase III clinical trials. Now, despite an improved understanding of the biology of the parasites and of the immune responses they stimulate in naturally exposed populations, the vaccine effort is stalled. The control effort has switched heavily in favour of the wider use of conventional chemotherapy with praziquantel, which is now affordable by all but the poorest countries. Disagreements among researchers in the schistosome field as to whether or not a vaccine is needed have not helped convince funding agencies that schistosomiasis vaccines, rather than drugs, should be a priority. With the schistosome genome projects at an advanced stage plus the power of the proteomics, perhaps it is still too early to call time on schistosome vaccine development.

Efficacy and side-effects of two praziquantel treatments against Schistosoma haematobium infection, among schoolchildren from Côte d'Ivoire

Praziquantel is the current drug of choice for the control of schistosome-attributable morbidity and is likely to remain so for several years. However, as there is concern that schistosomes might develop resistance to the drug, the monitoring of praziquantel's efficacy in different epidemiological settings is recommended. Here, the results of an innovative study of the drug's effectiveness, in an area in Côte d'Ivoire that is highly endemic for Schistosoma haematobium, are reported. Each of the subjects (354 schoolchildren aged 5-15 years) was given two oral doses of praziquantel (each of 40 mg/kg) 4 weeks apart. The numbers of schistosome eggs in urine samples collected over several consecutive days prior to the first and after the second treatment were then determined. High cure and egg reduction 'rates', of 93.0% and 96.6%, respectively, were found. Although mild and transient side-effects were frequently observed after the first treatments, no severe systemic complaints were recorded. When the 20 children who remained egg-positive after the second dose were each given a third dose of praziquantel, 16 (80%) of them responded and became egg-negative. Unfortunately, the schistosome strains infecting the remaining four children could not be investigated in detailed laboratory studies, because of the failure of eggs to hatch. There were therefore no unambiguous signs of resistance to praziquantel in this epidemiological setting. The benefits and disadvantages, compared with single-dose treatments, of administering praziquantel twice within a few weeks are discussed. It is anticipated that this approach might prove efficacious in areas of high infection intensity. The integration of such pharmaceutical measures with other readily available control tools is likely to mitigate the current, intolerable burden of schistosomiasis.

Comparative study of the effects of artemether and artesunate on juvenile and adult Schistosoma mansoni in experimentally infected mice

Artemether and artesunate, derivatives of the antimalarial artemisinin, also exhibit antischistosomal properties. There is a need to assess comparatively the activity of both compounds against different developmental stages of schistosome parasites. Since artemisinin derivatives will be increasingly used to treat malaria, it is important to study the effects of 7-day monotherapy regimens on schistosome infections. We carried out experiments with mice, infected with juvenile or adult Schistosoma mansoni, and treated with artemether or artesunate at various doses and regimens including those currently used for monotherapy of malaria. Three doses of artemether, at concentrations of 150 or 300 mg/kg, administered to mice with juvenile S. mansoni resulted in worm reductions of 88-97%, which were significantly higher than the 67-77% obtained with artesunate (P < 0.05). Total concentrations of 600 or 800 mg/kg artemether, administered over 2 or 4 consecutive days to mice with adult S. mansoni, reduced the worm burden significantly by 46-51% (P < 0.05). The reduction of the worm burden observed with artesunate was considerably lower, 24-33%, and not significant when compared with untreated control mice. Seven-day monotherapy regimens of artemether or artesunate given at different concentrations to mice with adult S. mansoni showed total worm reductions of 53-61% or 34-49%, respectively. We conclude that artemether and artesunate are efficacious antischistosomal agents, with artemether displaying consistently higher activities. Our findings may contribute to the current strategic discussions on the effect and use of artemisinin derivatives against schistosomes when they are used in malaria chemotherapy in areas of co-endemicity of both parasites.