New drugs, drug combinations and improved diagnostics for the control of helminthic infections

Neglected Tropical Diseases (NTDs) represent one of the biggest health challenges in tropical and subtropical countries. They are most commonly caused by helminths, including the soil-transmitted helminths (STH) (Ascaris lumbricoides, Trichuris trichiura, Ancylostoma duodenale and Necator americanus), Schistosoma spp (S. haematobium, S. mansoni, S. japonicum being the most common) and Strongyloides stercoralis. Helminth infections are widely distributed but prevalence is highest in low-resource settings in subSaharan Africa, the Americas and Asia. Helminthic infections are more common in children, and, when chronic may be responsible for severe morbidities that interfere with normal growth and cognitive development. Preventive chemotherapy (PC) is the main strategy promoted by the World Health Organization to control morbidities linked to NTDs. This intervention is based on regular anthelminthic treatment of in-need populations in endemic areas. Diagnostic methods for the detection of these infections suffer from low sensitivity and new approaches, such as molecular techniques, that may improve sensitivity, often are not applicable in field laboratories where expensive tools are not affordable. The treatment of NTDs relies on few drugs: benzimidazoles (albendazole and mebendazole) for STH, praziquantel for schistosomiasis and ivermectin for onchocerciasis, lymphatic filariasis and strongyloidiasis. PC programs are highly effective but the regular use of the few available drugs in a vast population raises concern regarding development of resistance. Although confirmed resistance has not yet been proved, a lower sensitivity to praziquantel has been reported in populations who received several rounds of PC. Additionally, benzimidazoles are scarcely effective against T. trichiura. Therefore, there is a great need of new effective drugs to tackle these infections. In the frame of my PhD program, I addressed the need of developing new drugs against helminthic infections by testing the efficacy of moxidectin, a macrocyclic lactone used in veterinary medicine, against STH, S. haematobium, S. mansoni, and S. stercoralis in exploratory randomized Phase 2 trials. We confirmed its good efficacy against S. stercoralis but not against Schistosoma spp. In our randomized non-inferiority Phase 2 clinical trial conducted with different drug combinations, moxidectin in co-administration with albendazole showed a good efficacy against STH infections. From a diagnostic point of view, we assessed the sensitivity of two DNA extraction methods for the detection of S. stercoralis using PCR; this technique showed a good potential but further studies are still necessary to improve its standardization. We also conducted an ultrasound assessment of the impact of different doses of praziquantel on urinary tract morbidity in S. haematobium infected children versus placebo. We found that light and moderate bladder morbidity has an early onset, and is present in pre-school-aged children. Six months after treatment we registered 90% of regression of morbidity in treated children and only 10% in the placebo group. Our findings contribute to the development of moxidectin against helminthic infections. Our findings indicate that this drug is worth further evaluations before it can be promoted for public health campaigns. Furthermore, our data might foster the development of new potential diagnostics for NTDs such as S. stercoralis. Eventually, we confirmed the relevance of PC for the control of morbidity due to urogenital schistosomiasis that can be assessed in the field by relatively simple tools such as ultrasound

Efficacy and safety of moxidectin, synriam, synriam-praziquantel versus praziquantel against schistosoma haematobium and S. mansoni infections: a randomized, exploratory phase 2 trial

Schistosomiasis affects millions of people, yet treatment options are limited. The antimalarial Synriam (piperaquine 150 mg/arterolane 750 mg) and the anthelminthic moxidectin revealed promising antischistosomal properties in preclinical or clinical studies.; We conducted two single-blind, randomized exploratory Phase 2 trials in Schistosoma mansoni and S. haematobium-infected adolescents in northern and central Côte d'Ivoire. Our primary endpoints were cure rates (CRs) and egg reduction rates (ERRs) based on geometric mean and safety. Each subject was asked to provide two stool samples (S. mansoni trial) for Kato-Katz analysis or three urine samples (S. haematobium trial) for urine filtration and one finger prick for malaria screening at baseline and follow-up. Participants were randomly assigned to either moxidectin, Synriam, Synriam plus praziquantel or praziquantel.; 128 adolescents (age: 12-17 years) were included in each study. Against S. haematobium moxidectin and Synriam revealed low efficacy. On the other hand, Synriam plus praziquantel and praziquantel yielded CRs of 60.0% and 38.5% and ERRs of 96.0% and 93.5%, respectively. CRs observed in the treatment of S. mansoni were 13.0%, 6.7%, 27.0%, and 27.6% for moxidectin, Synriam, Synriam plus praziquantel and praziquantel, respectively. ERRs ranged from 64.9% (Synriam) to 87.5% (praziquantel).; Synriam and moxidectin show low efficacy against S. haematobium, hence an ancillary benefit is not expected when these drugs are used for treating onchocerciasis and malaria in co-endemic settings. Further studies are needed to corroborate our findings that moxidectin and Synriam show moderate ERRs against S. mansoni

Mini-FLOTAC, an Innovative Direct Diagnostic Technique for Intestinal Parasitic Infections: Experience from the Field.

Soil-transmitted helminths and intestinal protozoa infection are widespread in developing countries, yet an accurate diagnosis is rarely performed. The aim of this study was to evaluate the recently developed mini-FLOTAC method and to compare with currently more widely used techniques for the diagnosis of intestinal parasitic infections in different settings. The study was carried out in Dharamsala, Himachal Pradesh, India, and in Bukumbi, Tanzania. A total of 180 pupils from two primary schools had their stool analyzed (n = 80 in Dharamsala and n = 100 in Bukumbi) for intestinal parasitic infections with three diagnostic methods: direct fecal smear, formol-ether concentration method (FECM) and mini-FLOTAC. Overall, 72% of the pupils were positive for any intestinal parasitic infection, 24% carried dual infections and 11% three infections or more. The most frequently encountered intestinal parasites were Entamoeba coli, Entamoeba histolytica/dispar, Giardia intestinalis, hookworm, (and Schistosoma mansoni, in Tanzania). Statistically significant differences were found in the detection of parasitic infections among the three methods: mini-FLOTAC was the most sensitive method for helminth infections (90% mini-FLOTAC, 60% FECM, and 30% direct fecal smear), whereas FECM was most sensitive for intestinal protozoa infections (88% FECM, 70% direct fecal smear, and 68% mini-FLOTAC). We present the first experiences with the mini-FLOTAC for the diagnosis of intestinal helminths and protozoa. Our results suggest that it is a valid, sensitive and potentially low-cost alternative technique that could be used in resource-limited settings--particularly for helminth diagnosis

Current pharmacotherapeutic strategies for Strongyloidiasis and the complications in its treatment

Introduction: Strongyloidiasis, an infection caused by the soil-transmitted helminth Strongyloides stercoralis, can lead immunocompromised people to a life-threatening syndrome. We highlight here current and emerging pharmacotherapeutic strategies for strongyloidiasis and discuss treatment protocols according to patient cohort. We searched PubMed and Embase for papers published on this topic between 1990 and May 2022. Areas covered: Ivermectin is the first-line drug, with an estimated efficacy of about 86% and excellent tolerability. Albendazole has a lower efficacy, with usage advised when ivermectin is not available or not recommended. Moxidectin might be a valid alternative to ivermectin, with the advantage of being a dose-independent formulation. Expert opinion: The standard dose of ivermectin is 200 mu g/kg single dose orally, but multiple doses might be needed in immunosuppressed patients. In the case of hyperinfection, repeated doses are recommended up to 2 weeks after clearance of larvae from biological fluids, with close monitoring and further dosing based on review. Subcutaneous ivermectin is used where there is impaired intestinal absorption/paralytic ileus. In pregnant or lactating women, studies have not identified increased risk with ivermectin use. However, with limited available data, a risk-benefit assessment should be considered for each case

Comparison of real-time PCR and the Kato-Katz method for the diagnosis of soil-transmitted helminthiasis and assessment of cure in a randomized controlled trial

Diagnosis of soil-transmitted helminths (STHs) in developing countries is commonly based on microscopic detection of eggs in stool samples, using the Kato-Katz (KK) method, which has a poor sensitivity for detecting light intensity infections. We compared the performance of the KK method and real-time PCR in the framework of a randomized trial, which evaluated four novel treatments against Trichuris trichiura and concomitant STH infections.; Two stool samples obtained from 320 participants were examined at baseline and follow-up with quadruplicate KK and PCR analyses of one of the two samples using "bead-beating" for DNA extraction. At follow-up, 80 samples were negative according to both PCR and KK and 173 were positive with both methods for any of the STHs. Relative to PCR, the calculated sensitivity of KK at follow-up was 83.6%, 43.0% and 53.8% for T. trichiura, for hookworm and for Ascaris lumbricoides, respectively. The sensitivity of PCR compared with KK at this time point was 89.1% for T. trichiura, 72.7% for hookworm and 87.5% for A. lumbricoides. Cure rates (CRs) for T. trichiura and A. lumbricoides were slightly lower with the PCR method. For hookworm CRs with KK were mostly significantly lower, namely 36.7%, 91.1%, 72.2% and 77.8% for moxidectin, moxidectin in combination with tribendimidine, moxidectin in combination with albendazole and albendazole in combination with oxantel pamoate, respectively, whereas with PCR the CRs were 8.3%, 82.6%, 37.1% and 57.1%, respectively.; In conclusion, a single real-time PCR is as sensitive as quadruplicate KK for T. trichiura and A. lumbricoides detection but more sensitive for hookworm, which has an influence on the estimated treatment efficacy. PCR method with DNA extraction using the "bead-beating protocol" should be further promoted in endemic areas and laboratories that can afford the needed equipment. The study is registered at ISRCTN (no. 20398469)

Evaluation of the Clinitek®, a point-of-care urinalysis system for the measurement of clinically significant urinary metabolites and detection of haematuria in Schistosoma haematobium infected children in southern Côte d'Ivoire

Urinary schistosomiasis, caused by Schistosoma haematobium, remains a significant public health problem worldwide, despite years of efforts to control it. Haematuria is one of the notable indirect indicators of S. haematobium infection and is commonly assessed along with other routine screens using a urinary dipstick test. A portable "field friendly" electronic analyser would offer an automated and thus more objective read-out compared to visual-read dipstick methods.; Within the framework of a Phase 2 praziquantel dose finding study in preschool- and school-aged children infected with S. haematobium, in southern Côte d'Ivoire, we compared a visual-read of the urine dipstick strips (Multistix PRO, Siemens Healthcare Diagnostics) to an automated reader (CLINITEK Status+ analysertm Siemens Healthcare Diagnostics). Urine samples were collected from 148 pre-school aged and 152 school-aged children for urinalysis. Values were compared using a linear weighted kappa statistic and Bland-Altman analysis.; A very good correlation between the two methods for nitrites and haematuria was observed (κ coefficient of 0.88 and 0.82, respectively), while a good correlation was observed for leukocytes (κ coefficient of 0.63) A moderate to fair correlation was calculated (κ coefficient ≤ 0.6) for all other parameters. When the results were stratified according to infection intensity, the agreements were stronger from the high infection intensity sample measurements, for most of the parameters.; Our results demonstrate the device's utility in detecting haematuria and nitrites but underline the need for further development of this tool in order to improve its performance in the field

Mini-FLOTAC, Kato-Katz and McMaster: three methods, one goal; highlights from north Argentina

Background: Copro-parasitological diagnosis is still a challenge in management of helminth infections at individualand community levels in resource-limited settings.The aim of our study was to compare the performance of three quantitative techniques: Kato-Katz, McMaster andMini-FLOTAC methids. The study was carried out in Oran, Northern Argentina.Methods: 200 schoolchildren were enrolled to provide a single stool sample, which was tested for helminthinfections with Kato-Katz, McMaster and Mini-FLOTAC methods. The Mini-FLOTAC was performed with two flotationsolutions (FS2 saturated saline and FS7 zinc sulphate). Preparation and reading time for each of the three methodswas calculated both when processing single and multiple samples.Results: Out of 193 schoolchildren examined, 40% were positive for any helminth infection by any method; themost prevalent was Hymenolepis nana (23%) followed by Ascaris lumbricoides (17%) and a third group of lessprevalent helminths: Enterobius vermicularis, Trichuris trichiura and hookworms (11% all together). Mini-FLOTAC FS2was more sensitive than FS7 for H. nana (93% vs 78%) and for other helminths (85% vs 80%), whereas FS7 was moresensitive for A. lumbricoides (87% vs 61%). Kato-Katz method was more sensitive than McMaster method for A.lumbricoides (84% vs 48%) and for other helminths (48% vs 43%) except for H. nana (49% vs 61%). As for eggcounts, Mini-FLOTAC FS2 reported 904 eggs per gram of faeces (EPG) for H. nana (vs 457 with McMaster and 111with Kato-Katz) and 1177 EPG for A. lumbricoides (vs 1315 with Kato-Katz and 995 with McMaster); FS2 detected thehighest EPG for both H.nana and A.lumbricoides (904 vs 568 and 1177 vs 643 respectively), the differences werenot statistically significant. The technique feasibility was calculated: Kato-Katz mean time was 48 minutes/sample,Mini-FLOTAC 13 minutes/sample and McMaster 7 minutes/sample. However, especially for Kato-Katz and Mini-FLOTAC,the mean time (min/sample) decreased significantly when processing multiple samples.Conclusions: Mini-FLOTAC is a promising technique for helminth diagnosis, it is more sensitive than Kato-Katz andMcMaster for H. nana and as sensitive as Kato-Katz and more sensitive than McMaster for A. lumbricoides identification.Egg counts differences although relevant, did not reach statistical significance.Fil: Barda, Beatrice. San Raffaele Hospital; ItaliaFil: Cajal, Pamela. Universidad Nacional de Salta. Sede Regional Oran. Instituto de Investigación de Enfermedades Tropicales; ArgentinaFil: Villagran, Eliana. Universidad Nacional de Salta. Sede Regional Oran. Instituto de Investigación de Enfermedades Tropicales; ArgentinaFil: Cimino, Ruben. Universidad Nacional de Salta. Sede Regional Oran. Instituto de Investigación de Enfermedades Tropicales; ArgentinaFil: Juarez, Marisa. Universidad Nacional de Salta. Sede Regional Oran. Instituto de Investigación de Enfermedades Tropicales; ArgentinaFil: Krolewiecki, Alejandro Javier. Universidad Nacional de Salta. Sede Regional Oran. Instituto de Investigación de Enfermedades Tropicales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Patología Experimental; ArgentinaFil: Rinaldi, Laura. Universidad de Napoles Federico III; ItaliaFil: Cringoli, Giuseppe. Universidad de Napoles Federico III; ItaliaFil: Burioni, Roberto. San Raffaele Hospital; ItaliaFil: Albonico, Marco. Ivo de Carneri Foundation; Itali

Efficacy of moxidectin versus ivermectin against Strongyloides stercoralis infections: a randomized controlled non-inferiority trial

Infections with Strongyloides stercoralis are of considerable public health relevance. Moxidectin, a well-established drug in veterinary medicine under consideration for regulatory submission for the treatment of onchocerciasis, might serve as an alternative to the widely used ivermectin.; We conducted an exploratory, randomized, single-blind trial to evaluate the efficacy and safety of moxidectin (8 mg) vs ivermectin (200 μg/kg) against S. stercoralis infections. Cure rate (CR) against S. stercoralis was the primary outcome. Safety and efficacy against coinfections with soil-transmitted helminths and Opisthorchis viverrini were secondary outcomes. Noninferiority required the lower limit of the 95% confidence interval (CI) of the differences in CRs not exceed 7 percentage points.; A total of 127 participants were enrolled and randomly assigned to the 2 treatments whereby 1 participant per arm was lost to follow-up. We observed a CR of 93.7% (59/63) for moxidectin compared to 95.2% (59/62) for ivermectin. Differences between CRs were estimated as -1.5% percentage points (95% CI, -9.6 to 6.5), thus the lower limit of the CI exceeds the noninferiority margin of 7 percentage points. No side effects were observed. CRs against hookworm infection were 57% (moxidectin) and 56% (ivermectin). Low efficacy for both drugs against O. viverrini was observed.; Moxidectin might be a safe and efficacious alternative to ivermectin for the treatment of S. stercoralis infection, given that only slight differences in CRs were observed. However, noninferiority could not be demonstrated. Larger clinical trials should be conducted once the drug is marketed.; Current Controlled Trials: ISRCTN11983645

A rapid appraisal of factors influencing praziquantel treatment compliance in two communities endemic for schistosomiasis in Côte d'Ivoire

Over the past decade, a significant reduction in the prevalence of schistosomiasis has been achieved, partially explained by the large-scale administration of praziquantel. Yet, the burden of schistosomiasis remains considerable, and factors influencing intervention coverage are important. This study aimed to deepen the understanding of low treatment coverage rates observed in two schistosomiasis-endemic villages in Côte d'Ivoire. The research was conducted in August 2015, in Moronou and Bigouin, two villages of Côte d'Ivoire that are endemic for; Schistosoma haematobium; and; S. mansoni; , respectively. After completion of a clinical trial, standard praziquantel treatment (single 40 mg/kg oral dose) was offered to all village inhabitants by community health workers using a house-to-house approach. Factors influencing treatment coverage were determined by a questionnaire survey, randomly selecting 405 individuals. The overall treatment coverage rate was only 47.6% (2730/5733) with considerable intervillage heterogeneity (27.7% in Bigouin (302/1091) versus 52.3% in Moronou (2428/4642)). Among the 200 individuals interviewed in Moronou, 50.0% were administered praziquantel, while only 19.5% of the 205 individuals interviewed in Bigouin received praziquantel. The main reasons for low treatment coverage were work-related (agricultural activities), the bitter taste of praziquantel and previous experiences with adverse events. The most suitable period for treatment campaigns was reported to be the dry season. More than three-quarter of the interviewees who had taken praziquantel (overall, 116/140; Moronou, 84/100; Bigouin, 32/40) declared that they would not participate in future treatments (; p; < 0.001). In order to enhance praziquantel treatment coverage, careful consideration should be given to attitudes and practices, such as prior or perceived adverse events and taste of praziquantel, and appropriate timing, harmonized with agricultural activities. Without such understanding, breaking the transmission of schistosomiasis remains a distant goal

StrongNet: An International Network to Improve Diagnostics and Access to Treatment for Strongyloidiasis Control

Strongyloidiasis is a disease caused by an infection with a soil-transmitted helminth that affects, according to largely varying estimates, between 30 million and 370 million people worldwide [1,2]. Not officially listed as a neglected tropical disease (NTD), strongyloidiasis stands out as particularly overlooked [3]. Indeed, there is a paucity of research and public health efforts pertaining to strongyloidiasis. Hence, clinical, diagnostic, epidemiologic, treatment, and control aspects are not adequately addressed to allow for an effective management of the disease, both in clinical medicine and in public health programs [4]. The manifold signs and symptoms caused by Strongyloides stercoralis infection, coupled with the helminth’s unique potential to cause lifelong, persistent infection, make strongyloidiasis relevant beyond tropical and subtropical geographic regions, where, however, most of the disease burden is concentrated. Indeed, strongyloidiasis is acquired through contact with contaminated soil, and the infection is, thus, primarily transmitted in areas with poor sanitation, inadequate access to clean water, and lack of hygiene