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Infectious Diseases of Poverty Mar 2017Even though Rwanda lies within a region that has a high prevalence of schistosomiasis and soil-transmitted helminth (STH) infections, epidemiological information... (Review)
Review
Even though Rwanda lies within a region that has a high prevalence of schistosomiasis and soil-transmitted helminth (STH) infections, epidemiological information regarding these infections in the country remains scarce. The present review attempts to compile the available data on schistosomiasis and STHs, from 1940 to 2014, to provide an insight on the epidemiological profile of these infections. This information will, in turn, support the design and implementation of sustainable control measures. The available records indicate that only Schistosoma mansoni and all the major species of STHs are endemic in Rwanda. In 2008, the national prevalence of S. mansoni was reported to be 2.7%, ranging from 0 to 69.5%, and that of STH infections was 65.8% (diagnosed using the Kato-Katz technique). The prevalence of these infections varies from one district to another, with schoolchildren remaining a highly affected group. The main control approach is mass drug administration using albendazole and praziquantel, mostly targeting school-aged children in school environments. In 2008, adult individuals living in areas with a prevalence of S. mansoni ≥30% were also included in the mass drug administration programme. However, despite Rwanda achieving an almost 100% coverage of this programme in 2008-2010, the transmission of S. mansoni and STHs continues to take place, as illustrated by the most recent surveys. If Rwanda is to achieve sustainable control and elimination of schistosomiasis and STHs, there is a need to revise the country's control strategy and adopt an integrated control approach that involves a combination of measures.
Topics: Albendazole; Animals; Anthelmintics; Communicable Disease Control; Disease Transmission, Infectious; Endemic Diseases; Helminthiasis; Humans; Praziquantel; Prevalence; Rwanda
PubMed: 28245883
DOI: 10.1186/s40249-016-0212-z -
Trends in Parasitology Dec 2023The World Health Organization (WHO) recently proposed a new operational definition which designates communities with ≥10% prevalence of Schistosoma spp. infection as a... (Review)
Review
The World Health Organization (WHO) recently proposed a new operational definition which designates communities with ≥10% prevalence of Schistosoma spp. infection as a persistent hotspot, when, after at least two rounds of high-coverage annual preventive chemotherapy, there is a lack of appropriate reduction. However, inconsistencies and challenges from both biological and operational perspectives remain, making the prescriptive use of this definition difficult. Here, we present a comprehensive analysis of the use of the term 'hotspot' across schistosomiasis research over time, including both literature searches and opinions from a range of stakeholders, to assess the utility and generalisability of the new WHO definition of a persistent hotspot. Importantly, we propose an updated definition based on our analyses.
Topics: Animals; Praziquantel; Anthelmintics; Schistosoma haematobium; Schistosomiasis; Schistosoma mansoni
PubMed: 37806786
DOI: 10.1016/j.pt.2023.09.006 -
Journal of Veterinary Internal Medicine May 2021Established treatment protocols for schistosomiasis (Heterobilharzia americana) in dogs are expensive. Anecdotal reports suggest that lower doses of praziquantel,...
BACKGROUND
Established treatment protocols for schistosomiasis (Heterobilharzia americana) in dogs are expensive. Anecdotal reports suggest that lower doses of praziquantel, combined with fenbendazole, may eliminate asymptomatic infections.
OBJECTIVES
Evaluate the efficacy of a low-dose praziquantel and fenbendazole protocol to manage asymptomatic schistosomiasis in dogs and compare fecal saline sedimentation (FSS) and fecal PCR (FPCR) for therapeutic monitoring.
ANIMALS
Twelve asymptomatic dogs with positive FPCR and FSS results for schistosomiasis.
METHODS
Prospective observational study. On day 0, dogs received praziquantel at a median dose of 5 mg/kg PO q8h for 2 days, with fenbendazole at 24 mg/kg PO q24h for 7 days. Fecal PCR and FSS were repeated in all dogs on days 30, 60, and 90.
RESULTS
By day 30, 10 of 12 dogs were negative by FSS, but only 3 of 12 were negative by FPCR. By day 60, all 12 dogs were negative by FSS, and 8 of 12 had become negative by FPCR. By day 90, all 12 dogs remained negative by FSS, but 5 of 12 were positive by FPCR (including 2 that were negative by FPCR on day 60). Three dogs that were positive by FPCR on day 60 were re-treated and subsequently became both FPCR and FSS negative. One FPCR-positive dog developed a mild increase in serum ALP activity, another developed mild hypercalcemia, and a third developed diarrhea.
CONCLUSIONS AND CLINICAL IMPORTANCE
A low-dose praziquantel/fenbendazole protocol may be effective for asymptomatic schistosomiasis in some dogs, but monitoring to ensure treatment success is recommended. Fecal saline sedimentation and FPCR may demonstrate discrepant results, with FPCR being positive more frequently.
Topics: Animals; Dog Diseases; Dogs; Fenbendazole; Praziquantel; Schistosomatidae; Schistosomiasis
PubMed: 33955589
DOI: 10.1111/jvim.16142 -
Molecules (Basel, Switzerland) Sep 2017Schistosomiasis, which is caused by helminth trematode blood flukes of the genus , is a serious health and economic problem in tropical areas, and the second most... (Review)
Review
Schistosomiasis, which is caused by helminth trematode blood flukes of the genus , is a serious health and economic problem in tropical areas, and the second most prevalent parasitic disease after malaria. Currently, there is no effective vaccine available and treatment is entirely dependent on a single drug, praziquantel (PZQ), raising a significant potential public health threat due to the emergence of PZQ drug resistance. It is thus urgent and necessary to explore novel therapeutic targets for the treatment of schistosomiasis. Previous studies demonstrated that acetylcholinesterase (AChE) and nicotinic acetylcholine receptors (nAChRs) play important roles in the schistosome nervous system and ion channels, both of which are targeted by a number of currently approved and marketed anthelminthic drugs. To improve understanding of the functions of the cholinergic system in schistosomes, this article reviews previous studies on AChE and nAChRs in schistosomes and other helminths and discusses their potential as suitable targets for vaccine development and drug design against schistosomiasis.
Topics: Acetylcholinesterase; Animals; Anthelmintics; Drug Design; Drug Resistance; Helminths; Humans; Praziquantel; Receptors, Nicotinic; Schistosoma; Schistosomiasis; Vaccines
PubMed: 28906438
DOI: 10.3390/molecules22091550 -
The Cochrane Database of Systematic... Aug 2014Urinary schistosomiasis is caused by an intravascular infection with parasitic Schistosoma haematobium worms. The adult worms typically migrate to the venous plexus of... (Meta-Analysis)
Meta-Analysis Review
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.
Topics: Adult; Anthelmintics; Artemisinins; Artesunate; Child; Humans; Mefloquine; Praziquantel; Randomized Controlled Trials as Topic; Schistosomiasis haematobia; Trichlorfon
PubMed: 25099517
DOI: 10.1002/14651858.CD000053.pub3 -
Ui Sahak Aug 2021The Korean parasite control program is regarded as one of the most successful examples of health care movement in Korea. This 'Parasite Eradication Program' which was...
The Korean parasite control program is regarded as one of the most successful examples of health care movement in Korea. This 'Parasite Eradication Program' which was conducted from 1969 to 1995, involved testing and treating of 300 million people. In cooperation with Japan, parasitologists and activists who participated in the parasite control program formed a common system called the 'Mass Testing, Mass Treatment.' This study focuses on the localization process of Praziquantel, Clonorchiasis treatment production and its application in Clonorchiasis control program. Parasitologists rapidly introduced newly developed Praziquantel, and Korean chemists quickly reverse engineered the compound to evade patent issues. This allowed for the mass production of Praziquantel at a lower price, which in turn enabled a nationwide Clonorchiasis control program. At the same time, low price and stable supply opened the private market for Praziquantel. However, acceptance and understanding of the Praziquantel differed significantly among the stakeholders. For the government, it was a means for policy propaganda, and for the health agencies, it was a means for mass scale control program, while for the public, it was a means for maintaining conventional eating habits without risk of infection. This study reveals how the material end of a disease control policy is accepted and interpreted by different actors.
Topics: Animals; Clonorchiasis; Clonorchis sinensis; Humans; Japan; Praziquantel; Republic of Korea
PubMed: 34663774
DOI: 10.13081/kjmh.2021.30.317 -
Infectious Disorders Drug Targets 2019Today 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... (Review)
Review
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.
Topics: Animals; Anthelmintics; Global Health; History, 20th Century; History, 21st Century; Humans; Praziquantel; Schistosoma; Schistosomiasis
PubMed: 30599112
DOI: 10.2174/1871526519666181231153139 -
The Lancet. Infectious Diseases Feb 2017Profound changes are occurring in the epidemiology of schistosomiasis, a neglected tropical disease caused by a chronic infection with parasitic helminths of the genus... (Review)
Review
Profound changes are occurring in the epidemiology of schistosomiasis, a neglected tropical disease caused by a chronic infection with parasitic helminths of the genus Schistosoma. Schistosomiasis currently affects 240 million people worldwide, mostly in sub-Saharan Africa. The advent and proliferation of mass drug administration (MDA) programmes using the drug praziquantel is resulting in substantial increases in the number of people, mainly children aged 6-14 years, being effectively treated, approaching the point where most people in endemic areas will receive one or more treatments during their lifetimes. Praziquantel treatment not only cures infection but also frees the host from the powerful immunomodulatory action of the parasites. The treatment simultaneously enhances exposure to key parasite antigens, accelerating the development of protective acquired immunity, which would take many years to develop naturally. At a population level, these changes constitute a substantial alteration to schistosome ecology in that the parasites are more likely to be exposed not only to praziquantel directly but also to hosts with altered immune phenotypes. Here, we consider the consequences of this for schistosome biology, immunoepidemiology, and public health. We anticipate that there could be substantial effects on chronic pathology, natural immunity, vaccine development strategies, immune disorders, and drug efficacy. This makes for a complex picture that will only become apparent over decades. We recommend careful monitoring and assessment to accompany the roll-out of MDA programmes to ensure that the considerable health benefits to populations are achieved and sustained.
Topics: Africa South of the Sahara; Animals; Anthelmintics; Humans; Praziquantel; Schistosoma; Schistosomiasis
PubMed: 27988094
DOI: 10.1016/S1473-3099(16)30475-3 -
Journal of Feline Medicine and Surgery Oct 2018Objectives The pharmacokinetics of praziquantel and pyrantel pamoate has never been reported in cats. The present study was designed to establish the plasma...
Objectives The pharmacokinetics of praziquantel and pyrantel pamoate has never been reported in cats. The present study was designed to establish the plasma concentration-time profile and to derive pharmacokinetic data for a combined formulation of praziquantel and pyrantel in cats, after a single, oral administration. Methods Twenty-two clinically healthy adult cats were used, each receiving a single oral dose of praziquantel (8.5 mg/kg) and pyrantel (100 mg/kg). Blood samples were collected at regular time points up to 48 h post-dosing. Plasma concentrations of praziquantel and pyrantel were measured using a liquid chromatography-mass spectrometry-high-throughput screening method. Results Clinical examination of all cats did not reveal any side effects after oral administration of these medications. The terminal half-life for praziquantel and pyrantel was 1.07 and 1.36 h, respectively. Praziquantel peak concentration (C) was 1140 μg/ml, reached at 1.22 h. The plasma concentrations of pyrantel after oral administration were low with a mean C of 0.11 μg/ml, reached at a T of 1.91 h. Pyrantel showed a very limited absorption as pamoate salt, suggesting permanence and efficacy inside the gastrointestinal tract, where the adult stages of most parasitic nematodes reside. Conclusions and relevance Pyrantel showed a very limited absorption as pamoate salt. Praziquantel was rapidly absorbed following oral administration and the concentrations achieved suggest that praziquantel could be an effective and safe medication in cats. Although some resistance problems are arising as a result of their long use, these anthelminthic products can still play a major role in parasitic control, especially in geographical areas where the high cost of newer treatments or necessity of parenteral administration could decrease the number of treated animals.
Topics: Administration, Oral; Animals; Anthelmintics; Area Under Curve; Cats; Drug Combinations; Female; Male; Praziquantel; Pyrantel Pamoate; Random Allocation; Treatment Outcome
PubMed: 29017390
DOI: 10.1177/1098612X17734065 -
Antimicrobial Agents and Chemotherapy May 2017Schistosomiasis, a major neglected tropical disease, affects more than 250 million people worldwide. Treatment of schistosomiasis has relied on the anthelmintic drug... (Review)
Review
Schistosomiasis, a major neglected tropical disease, affects more than 250 million people worldwide. Treatment of schistosomiasis has relied on the anthelmintic drug praziquantel (PZQ) for more than a generation. PZQ is the drug of choice for the treatment of schistosomiasis; it is effective against all major forms of schistosomiasis, although it is less active against juvenile than mature parasites. A pyrazino-isoquinoline derivative, PZQ is not considered to be toxic and generally causes few or transient, mild side effects. Increasingly, mass drug administration targeting populations in sub-Saharan Africa where schistosomiasis is endemic has led to the appearance of reduced efficacy of PZQ, which portends the selection of drug-resistant forms of these pathogens. The synthesis of improved derivatives of PZQ is attracting attention, e.g., in the (i) synthesis of drug analogues, (ii) rational design of pharmacophores, and (iii) discovery of new compounds from large-scale screening programs. This article reviews reports from the 1970s to the present on the metabolism and mechanism of action of PZQ and its derivatives against schistosomes.
Topics: Africa South of the Sahara; Animals; Drug Resistance; Humans; Praziquantel; Schistosoma; Schistosomiasis; Schistosomicides
PubMed: 28264841
DOI: 10.1128/AAC.02582-16