The drugs we have and the drugs we need against major helminth infections

Prevalence and Predictors of Intestinal Parasitic Infections at King Abdulaziz University Hospital, Jeddah, Saudi Arabia, from 2019 to 2023: A Retrospective Study

Purpose

Parasitic infections are a primary cause of illness worldwide and a public health problem. This study highlighted the prevalence of intestinal parasitic (IP) infections and their updated epidemiologic status from 2019 to 2023 at King Abdulaziz University Hospital, Jeddah, Saudi Arabia.

Patients and Methods

A retrospective study was conducted from 2019 to 2023 at King Abdulaziz University Hospital. The laboratory results, socio-demographic information, and the year of data collection were collected from the hospital's parasitology laboratory. The data were analyzed using SPSS version 26. Ethical approval was obtained from the National Committee of Bioethics (NCBE) - King Abdul Aziz City for Science and Technology, with an approval number of 258-22.

Results

During the study period, 7673 stool samples were requested for intestinal parasite examination. The prevalence of IP infection from 2019 to 2023 was 212/7673, with a percentage of 2.8%. Infected patients had a mean (SD) age of 37.68 (17.27) years. Most infected patients were females (61%) and from Saudi Arabia (37.1%). Most stool samples were brown (79.1%), and about half were soft (51.7%). 2019 had the highest number of infected cases (28.3%), while the number of cases decreased in 2023 (8.8%), the lowest during five years. The most predominant parasite among study subjects was Blastocystis hominis (48.11%).

Conclusion

The prevalence of IP infection is lower than in previous comparable surveys. Maintaining personal hygiene, conducting epidemiological surveillance, and enhancing environmental sanitation can prevent and control infections.

New Insights on Tools for Detecting β-Tubulin Polymorphisms in Trichuris trichiura Using rhAmpTM SNP Genotyping

Soil-transmitted helminth (STH) infections, commonly treated with benzimidazoles, are linked to resistance through single nucleotide polymorphisms (SNPs) at position 167, 198, or 200 in the β-tubulin isotype 1 gene. The aim of this study was to establish a novel genotyping assay characterized by its rapidity and specificity. This assay was designed to detect the presence of SNPs within the partial β-tubulin gene of Trichuris trichiura. This was achieved through the biallelic discrimination at codons 167, 198, and 200 by employing the competitive binding of two allele-specific forward primers. The specificity and reliability of this assay were subsequently confirmed using Trichuris samples isolated from captive primates. Furthermore, a molecular study was conducted to substantiate the utility of the β-tubulin gene as a molecular marker. The assays showed high sensitivity and specificity when applied to field samples. Nevertheless, none of the SNPs within the β-tubulin gene were detected in any of the adult worms or eggs from the analyzed populations. All specimens consistently displayed an SS genotype. The examination of the β-tubulin gene further validated the established close relationships between the T. trichiura clade and Trichuris suis clade. This reaffirms its utility as a marker for phylogenetic analysis.

A Case of Clonorchiasis in a Non-endemic Region of China

Clonorchiasis, an important foodborne parasitic disease, is prevalent in several Asian countries. In China, the three provinces with the highest incidence are Guangdong, Guangxi, and Heilongjiang, with no reported cases in Qingdao for nearly a decade. In this study, a 29-year-old male patient was diagnosed with fatty liver due to abnormal liver function during physical examination and was admitted to the hospital multiple times for examination and treatment within 3 years, but his liver function did not improve. Eventually, clonorchis eggs were found in the stool, confirming the diagnosis of clonorchiasis. The purpose of this report is to enhance the understanding of clonorchiasis among clinicians in no-prevalence areas, to familiarize laboratory technicians with egg identification, to strengthen parasite-knowledge training, and to reduce missed and misdiagnosed cases.

An update on the current and emerging pharmacotherapy for the treatment of human ascariasis

INTRODUCTION

Globally, Ascaris lumbricoides is the commonest helminthic infection that affects people in underdeveloped countries and returning immigrants in industrialized nations. This article aims to provide latest updates on the epidemiology, clinical manifestations, and pharmacotherapy of ascariasis.

AREAS COVERED

A PubMed search was conducted using Clinical Queries and the key terms 'human ascariasis' OR 'Ascaris lumbricoides.' Ascaris lumbricoides is highly endemic in tropical and subtropic regions and among returning immigrants in industrialized nations. Predisposing factors include poor sanitation and poverty. The prevalence is greatest in young children. Most infected patients are asymptomatic. Patients with A. lumbricoides infection should be treated with anti-helminthic drugs to prevent complications from migration of the worm. Mebendazole and albendazole are indicated for children and nonpregnant women. Pregnant individuals should be treated with pyrantel pamoate.

EXPERT OPINION

Cure rates with anthelmintic treatment are high. No emerging pharmacotherapy can replace these existing drugs of good efficacy, safety profile and low cost for public health. It is opinioned that advances in the management of ascariasis include diagnostic accuracy at affordable costs, Emodepside is highly effective in single doses against ascarids in mammals and in human trials. The drug could be registered for human use in multiple neglected tropical diseases.

A review of health education activities targeting schoolchildren for the control of soil-transmitted helminthiasis in Southeast Asia, with emphasis upon the Magic Glasses approach

Soil-transmitted helminths continue to be a serious problem causing disease and morbidity globally. Children, mostly school-aged, are more at risk of these infections. The main strategy for control remains to be the mass drug administration (MDA) of antihelminthic drugs. With the limitation of MDA to prevent re-infection, the need for additional approaches such as hygiene education and improvements in water, sanitation and hygiene (WASH) infrastructure are required. Although the importance of health education as a crucial component of an integrated approaches to STH control is highlighted, this component has often been disregarded because the other more complex solutions have been the focus of most studies and programmes. We performed literature searches from four bibliographic databases - Scopus, PubMed, Web of Science and Cochrane Library - to determine availability of studies on the impact of health education interventions targeting STH infections on schoolchildren in Southeast Asia. Our review found only three studies that evaluated health education interventions targeting children. The current lack of evidence in this area suggests the need for more studies assessing the impact of health education intervention for STH control. A successful health education programme for STH called "The Magic Glasses" has been developed targeting schoolchildren in China and the Philippines. This public health intervention displayed significant impact in terms of improving knowledge, attitude and practices, reducing prevalence of STH infections in schoolchildren and encouraging compliance to MDA. This article details the successes and benefits of the Magic Glasses programme as a promising control tool for STH in the Southeast Asian region.

Combinations of the azaquinazoline anti-Wolbachia agent, AWZ1066S, with benzimidazole anthelmintics synergise to mediate sub-seven-day sterilising and curative efficacies in experimental models of filariasis

Lymphatic filariasis and onchocerciasis are two major neglected tropical diseases that are responsible for causing severe disability in 50 million people worldwide, whilst veterinary filariasis (heartworm) is a potentially lethal parasitic infection of companion animals. There is an urgent need for safe, short-course curative (macrofilaricidal) drugs to eliminate these debilitating parasite infections. We investigated combination treatments of the novel anti-Wolbachia azaquinazoline small molecule, AWZ1066S, with benzimidazole drugs (albendazole or oxfendazole) in up to four different rodent filariasis infection models: Brugia malayi-CB.17 SCID mice, B. malayi-Mongolian gerbils, B. pahangi-Mongolian gerbils, and Litomosoides sigmodontis-Mongolian gerbils. Combination treatments synergised to elicit threshold (>90%) Wolbachia depletion from female worms in 5 days of treatment, using 2-fold lower dose-exposures of AWZ1066S than monotherapy. Short-course lowered dose AWZ1066S-albendazole combination treatments also delivered partial adulticidal activities and/or long-lasting inhibition of embryogenesis, resulting in complete transmission blockade in B. pahangi and L. sigmodontis gerbil models. We determined that short-course AWZ1066S-albendazole co-treatment significantly augmented the depletion of Wolbachia populations within both germline and hypodermal tissues of B. malayi female worms and in hypodermal tissues in male worms, indicating that anti-Wolbachia synergy is not limited to targeting female embryonic tissues. Our data provides pre-clinical proof-of-concept that sub-seven-day combinations of rapid-acting novel anti-Wolbachia agents with benzimidazole anthelmintics are a promising curative and transmission-blocking drug treatment strategy for filarial diseases of medical and veterinary importance.

Paragonimiasis

Paragonimiasis is a zoonotic disease caused by lung flukes of the genus Paragonimus. Humans usually become infected by eating freshwater crabs or crayfish containing encysted metacercariae of these worms. However, an alternative route of infection exists: ingestion of raw meat from a mammalian paratenic host. Adult worms normally occur in pairs in cysts in the lungs from which they void their eggs via air passages. The pulmonary form is typical in cases of human infection due to P. westermani, P. heterotremus, and a few other species. Worms may occupy other sites in the body, notably the brain, but lung flukes have made their presence felt in almost every organ. Ectopic paragonimiasis is particularly common when infection is due to members of the P. skrjabini complex. Human paragonimiasis occurs primarily in the tropics and subtropics of Asia, Africa, and the Americas, with different species being responsible in different areas (Table 6.1).

Echinostomes and Other Intestinal Trematode Infections

Intestinal trematodes are among the most common types of parasitic worms. About 76 species belonging to 14 families have been recorded infecting humans. Infection commonly occurs when humans eat raw or undercooked foods that contain the infective metacercariae. These parasites are diverse in regard to their morphology, geographical distribution and life cycle, which make it difficult to study the parasitic diseases that they cause. Many of these intestinal trematodes have been considered as endemic parasites in the past. However, the geographical limits and the population at risk are currently expanding and changing in relation to factors such as growing international markets, improved transportation systems, new eating habits in developed countries and demographic changes. These factors make it necessary to better understand intestinal trematode infections. This chapter describes the main features of human intestinal trematodes in relation to their biology, epidemiology, host-parasite relationships, pathogenicity, clinical aspects, diagnosis, treatment and control.

Singab A. Botanicals against some important nematodal diseases: Ascariasis and hookworm infections

Ascariasis and intestinal parasitic nematodes are the leading cause of mass mortality infecting many people across the globe. In light of the various deleterious side effects of modern chemical-based allopathic drugs, our preferences have currently shifted towards the use of traditional plant-based drugs or botanicals for treating diseases. The defensive propensities in the botanicals against parasites have probably evolved during their co-habitation with parasites, humans and plants in nature and hence their combative interference in one another's defensive mechanisms has occurred naturally ultimately being very effective in treating diseases. This article broadly outlines the utility of plant-based compounds or botanicals prepared from various medicinal herbs that have the potential to be developed as effective therapies against the important parasites causing ascariasis and intestinal hookworm infections leading to ascariasis & infections and thereby human mortality, wherein allopathic treatments are less effective and causes enormous side-effects.

Nematicidal Characterization of Newly Synthesized Thiazine Derivatives Using Caenorhabditis elegans as the Model Organism

In humans, animals, and agriculture, parasitic nematode infection is a very serious issue. Many drugs are being used to control nematode infections. Owing to toxicity and nematodes' resistance to the available drugs, special attention is required to synthesize new drugs that are environmentally friendly with high-level efficacy. In the present study, various substituted thiazine derivatives (1 to 15) were synthesized, and the structures were confirmed by infrared, proton (¹H), and ¹³C NMR spectroscopies. The nematicidal potential of the synthesized derivatives was characterized using Caenorhabditis elegans (C. elegans) as a model organism. Among all synthesized compounds, 13 (LD₅₀ = 38.95 μg/mL) and 15 (LD₅₀ = 38.21 μg/mL) were considered the most potent compounds. Most compounds showed excellent anti-egg-hatching activity. Fluorescence microscopy confirmed that compounds 4, 8, 9, 13, and 15 displayed a high apoptotic effect. The expressions of gst-4, hsp-4, hsp16.2, and gpdh-1 genes were high in affected (treated with thiazine derivatives) C. elegans in comparison with normal C. elegans. The present research revealed that modified compounds are highly effective as they showed the gene level changes in the selected nematode. Due to structural modification in thiazine analogues, the compounds showed various modes of action. The most effective thiazine derivatives could be excellent candidates for novel broad-scale nematicidal drugs.

Yeast Particles for Encapsulation of Terpenes and Essential Oils

Terpenes and essential oils are materials of great commercial use due to their broad spectra of antibacterial, antifungal, membrane permeation enhancement and antioxidant biological properties, as well as for their use as flavors and fragrances. Yeast particles (YPs) are 3-5 µm hollow and porous microspheres, a byproduct of some food-grade yeast (Saccharomyces cerevisiae) extract manufacturing processes, that have been used for the encapsulation of terpenes and essential oils with high payload loading capacity (up to 500% weight) and efficiency, providing stability and sustained-release properties. This review focuses on encapsulation approaches for the preparation of YP-terpene and essential oil materials that have a wide range of potential agricultural, food and pharmaceutical applications.

Model validation for a knowledge and practices survey towards prevention of soil-transmitted helminth infections in rural villages in Indonesia

The rate of soil-transmitted helminth (STH) infection is estimated to be around 20% in Indonesia. Health promotion and health education are cost-effective strategies to supplement STH prevention and control programs. Existing studies suggest that quantitative tools for knowledge, attitudes and practices (KAP) are important to monitor effective community-based STH interventions. However, evidence is limited regarding the applicability of such tools. This study aims to identify the socio-demographic predictors for STH-related knowledge and practices and validate the quantitative tools in population use. A cross-sectional study design was conducted among residents of 16 villages in Central Java, Indonesia. Adult and child respondents were interviewed to assess general knowledge and practices in relation to STH. Two mixed effects models identified the significant factors in predicting knowledge and practice scores. The model predicted knowledge and practice scores were compared with the observed scores to validate the quantitative measurements developed in this study. Participants' socio-demographic variables were significant in predicting an individual's STH-related knowledge level and their hand washing and hygiene practices, taking into account household-level variability. Model validation results confirmed that the quantitative measurement tools were suitable for assessing STH associated knowledge and behaviour. The questionnaire developed in this study can be used to support school- and community-based health education interventions to maximize the effect of STH prevention and control programs.

Prevalence and Subtype Distribution of Blastocystis Isolated from School-Aged Children in the Thai-Myanmar Border, Ratchaburi Province, Thailand

Blastocystis is one of the most common enteric protozoa that inhabits the intestinal tract of humans and different animals. Moreover, it has a worldwide geographic distribution. Its main mode of transmission is via the fecal-oral route. At present, 26 subtypes are widely distributed across both humans and animals. The current study aimed to determine the prevalence and subtype distribution of Blastocystis among school-aged children living on the Thai-Myanmar border, Ratchaburi province, Thailand. In total, 508 samples were collected from children at six schools. The prevalence of Blastocystis infection was amplified and sequenced in the 600 bp barcode region of the small-subunit ribosomal RNA (SSU rRNA). The overall prevalence of Blastocystis infection was 3.35% (17/508). ST3 (11/17) was the most predominant subtype, followed by ST1 (5/17) and ST2 (1/17). A phylogenetic tree was constructed based on the Tamura92+G+I model using the maximum-likelihood algorithm. Surprisingly, all sequences of the ST3-positive samples were closely correlated with the cattle-derived sequence. Meanwhile, all sequences of the Blastocystis ST1-positive samples were closely correlated with the human-derived sequence. Nevertheless, further studies should be conducted to validate the zoonotic transmission of Blastocystis. Based on our findings, personal hygiene and sanitation should be improved to promote better health in children in this area.

Risk factors for intestinal parasite portage in an informal suburb on the West coast of Madagascar

The deprived area of the Metzinger Valley in the city of Mahajanga has many healthcare concerns due to repeated flooding during the rainy season. Improving this health situation requires a better knowledge of the pathogens present in this area and of the risk factors favoring their propagation. The aim of this study was to analyze the relationship between the household socioeconomic status and the presence of parasites in the faeces of children between 1 and 10 years of age in order to determine the risk factors for intestinal parasitosis. The study included 746 children, of whom 30% were infected with parasites. Entamoeba coli, a good indicator of environmental fecal contamination, was the most prevalent parasite with an observation frequency of 16.7% followed by Giardia lamblia with a prevalence of 10%. For helminths, Trichuris and Ascaris were the most prevalent respectively 5.4% and 1.8%. A large heterogeneity in the prevalence of parasites was observed from one neighborhood to another. However, multivariate analysis showed that these differences were not related to environmental factors or household structure, but rather to the economic level of the family, the education level of the mother as well as the age of the child. For example, the prevalence of Giardia decreased from 23.5% to 8% for children of mothers with little education to those with higher education, respectively. For E. coli, the prevalence is higher among poor households and school-aged children. In the frame of IRCOD project, mothers are being sensitized to hygiene and risk factors for transmission by intestinal parasites and the present study proposes a multidimensional approach as an assessment tool.

Detection of Benzimidazole Resistance-Associated Single-Nucleotide Polymorphisms in the Beta-Tubulin Gene in Trichuris trichiura from Brazilian Populations

Preventive chemotherapy is recommended by the WHO as the main strategy for controlling infections caused by nematodes in humans, aiming to eliminate the morbidity associated with these infections. This strategy consists of routine periodic administration of benzimidazoles, among other drugs. Although these drugs decrease the intensity of infections, they have the potential to exert selection pressure for genotypes bearing mutations associated with drug resistance, which may result in the establishment of resistant worm populations. There is evidence in the literature of resistance to these drugs in nematodes that infect humans, including in the species Trichuris trichiura. Single-nucleotide polymorphisms (SNPs) in the beta-tubulin gene located at codons 167, 198, and 200 are associated with the mechanism of resistance to benzimidazoles in nematodes. Here, we standardized a molecular technique based on an amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) to analyze codons 167, 198, and 200 of T. trichiura. The ARMS-PCR methodology was successfully established to evaluate the codons of interest. A total of 420 samples of individual eggs were analyzed from populations obtained from five Brazilian states. A mutation in codon 198 was observed at a frequency of 4.8% (20/420), while for the other two codons, no polymorphism was observed. This is the first report of the presence of this mutation in populations of T. trichiura in Brazil. This fact and the emergence of the problem already observed in other species reinforces the need for regular monitoring of SNPs related to benzimidazole resistance using techniques that are highly sensitive and specific.

An Open Label, Adaptive, Phase 1 Trial of High-Dose Oral Nitazoxanide in Healthy Volunteers: An Antiviral Candidate for SARS-CoV-2

Repurposing approved drugs may rapidly establish effective interventions during a public health crisis. This has yielded immunomodulatory treatments for severe coronavirus disease 2019 (COVID-19), but repurposed antivirals have not been successful to date because of redundancy of the target in vivo or suboptimal exposures at studied doses. Nitazoxanide is a US Food and Drug Administration (FDA) approved antiparasitic medicine, that physiologically-based pharmacokinetic (PBPK) modeling has indicated may provide antiviral concentrations across the dosing interval, when repurposed at higher than approved doses. Within the AGILE trial platform (NCT04746183) an open label, adaptive, phase I trial in healthy adult participants was undertaken with high-dose nitazoxanide. Participants received 1,500 mg nitazoxanide orally twice-daily with food for 7 days. Primary outcomes were safety, tolerability, optimum dose, and schedule. Intensive pharmacokinetic (PK) sampling was undertaken day 1 and 5 with minimum concentration (Cmin ) sampling on days 3 and 7. Fourteen healthy participants were enrolled between February 18 and May 11, 2021. All 14 doses were completed by 10 of 14 participants. Nitazoxanide was safe and with no significant adverse events. Moderate gastrointestinal disturbance (loose stools or diarrhea) occurred in 8 participants (57.1%), with urine and sclera discoloration in 12 (85.7%) and 9 (64.3%) participants, respectively, without clinically significant bilirubin elevation. This was self-limiting and resolved upon drug discontinuation. PBPK predictions were confirmed on day 1 but with underprediction at day 5. Median Cmin was above the in vitro target concentration on the first dose and maintained throughout. Nitazoxanide administered at 1,500 mg b.i.d. with food was safe with acceptable tolerability a phase Ib/IIa study is now being initiated in patients with COVID-19.

Multi-intervention integrated deworming strategy for sustained control of soil-transmitted helminths infections: a case study in Jiangsu Province, China

BACKGROUND

Soil-transmitted helminths (STH) infections still present a global health problem. Mass drug administration (MDA) is a widely applied strategy to reduce morbidity and mortality caused by STH. Yet, this approach has some shortcomings. In this study, we analyzed the impact of a multi-intervention integrated deworming approach including MDA, health education (HE), and environmental sanitation improvements (ESI) for sustained STH control in Jiangsu Province of China that was applied from 1989 to 2019.

METHODS

Data, including infection rate of STH, medications used, coverage of the medication, non-hazardous lavatory rate, and household piped-water access rate in rural areas, and actions related to HE and ESI were collected (from archives) and analyzed in this retrospective descriptive study. Pearson's correlation analysis was applied to test correlations.

RESULTS

There was a dramatic decline in the infection rate of STH from 1989 (59.32%) to 2019 (0.12%). From 1995 to 1999, MDA and HE were recommended in rural areas. A negative correlation was observed between infection rate and medication from 1994 to 1998 (r = - 0.882, P = 0.048). From 2000 to 2005, targeted MDA was given to high-risk populations with HE continuously promoting good sanitation behaviors. From 2006 to 2014, targeted MDA + HE and ESI were used to consolidate the control effect. ESI was strengthened from 2006, and a negative correlation was observed between the coverage rate of the non-hazardous lavatory and the infection rate from 2006 to 2019 (r = - 0.95, P < 0.001). The targeted MDA was interrupted in 2015, while continuous efforts like HE and ESI contributed in sustaining STH control.

CONCLUSIONS

Multi-intervention integrated deworming strategy contributes to the reduction of STH infections. This approach is a valuable example of how different interventions can be integrated to promote durable STH control.

Development of emodepside as a possible adulticidal treatment for human onchocerciasis-The fruit of a successful industrial-academic collaboration

Current mass drug administration (MDA) programs for the treatment of human river blindness (onchocerciasis) caused by the filarial worm Onchocerca volvulus rely on ivermectin, an anthelmintic originally developed for animal health. These treatments are primarily directed against migrating microfilariae and also suppress fecundity for several months, but fail to eliminate adult O. volvulus. Therefore, elimination programs need time frames of decades, well exceeding the life span of adult worms. The situation is worsened by decreased ivermectin efficacy after long-term therapy. To improve treatment options against onchocerciasis, a drug development candidate should ideally kill or irreversibly sterilize adult worms. Emodepside is a broad-spectrum anthelmintic used for the treatment of parasitic nematodes in cats and dogs (Profender and Procox). Our current knowledge of the pharmacology of emodepside is the result of more than 2 decades of intensive collaborative research between academia and the pharmaceutical industry. Emodepside has a novel mode of action with a broad spectrum of activity, including against extraintestinal nematode stages such as migrating larvae or macrofilariae. Therefore, emodepside is considered to be among the most promising candidates for evaluation as an adulticide treatment against onchocerciasis. Consequently, in 2014, Bayer and the Drugs for Neglected Diseases initiative (DNDi) started a collaboration to develop emodepside for the treatment of patients suffering from the disease. Macrofilaricidal activity has been demonstrated in various models, including Onchocerca ochengi in cattle, the parasite most closely related to O. volvulus. Emodepside has now successfully passed Phase I clinical trials, and a Phase II study is planned. This Bayer–DNDi partnership is an outstanding example of “One World Health,” in which experience gained in veterinary science and drug development is translated to human health and leads to improved tools to combat neglected tropical diseases (NTDs) and shorten development pathways and timelines in an otherwise neglected area.

Onchocerca volvulus is the causative agent of human river blindness, and current elimination programs rely on the use of ivermectin to kill microfilariae. Since no adulticidal drug is available and adult worms have a life span of up to 15 years, elimination programs need to be sustained over several decades. Emodepside is an anthelmintic that is licensed as a dewormer for cats and dogs. Due to its ability to eliminate nematodes located in various extraintestinal host tissues, including migrating larvae and adult filarial worms, it is considered to be an excellent candidate for the treatment of onchocerciasis. Intense collaboration between academia and the pharmaceutical industry has led to a deep understanding of the novel mode of action of the drug and of its parasite target spectrum. Phase I clinical trials with emodepside have demonstrated its safety and adulticide activity against the closely related cattle parasite Onchocerca ochengi. Currently, Phase II clinical trials are planned to confirm that emodepside, developed initially to improve animal health, has also the potential to improve human health by tackling a very important neglected tropical disease (NTD).

Emodepside targets SLO-1 channels of Onchocerca ochengi and induces broad anthelmintic effects in a bovine model of onchocerciasis

Onchocerciasis (river blindness), caused by the filarial worm Onchocerca volvulus, is a neglected tropical disease mostly affecting sub-Saharan Africa and is responsible for >1.3 million years lived with disability. Current control relies almost entirely on ivermectin, which suppresses symptoms caused by the first-stage larvae (microfilariae) but does not kill the long-lived adults. Here, we evaluated emodepside, a semi-synthetic cyclooctadepsipeptide registered for deworming applications in companion animals, for activity against adult filariae (i.e., as a macrofilaricide). We demonstrate the equivalence of emodepside activity on SLO-1 potassium channels in Onchocerca volvulus and Onchocerca ochengi, its sister species from cattle. Evaluation of emodepside in cattle as single or 7-day treatments at two doses (0.15 and 0.75 mg/kg) revealed rapid activity against microfilariae, prolonged suppression of female worm fecundity, and macrofilaricidal effects by 18 months post treatment. The drug was well tolerated, causing only transiently increased blood glucose. Female adult worms were mostly paralyzed; however, some retained metabolic activity even in the multiple high-dose group. These data support ongoing clinical development of emodepside to treat river blindness.

Albendazole and Mebendazole as Anti-Parasitic and Anti-Cancer Agents: an Update

The use of albendazole and mebendazole, i.e., benzimidazole broad-spectrum anthelmintics, in treatment of parasitic infections, as well as cancers, is briefly reviewed. These drugs are known to block the microtubule systems of parasites and mammalian cells leading to inhibition of glucose uptake and transport and finally cell death. Eventually they exhibit ovicidal, larvicidal, and vermicidal effects on parasites, and tumoricidal effects on hosts. Albendazole and mebendazole are most frequently prescribed for treatment of intestinal nematode infections (ascariasis, hookworm infections, trichuriasis, strongyloidiasis, and enterobiasis) and can also be used for intestinal tapeworm infections (taeniases and hymenolepiasis). However, these drugs also exhibit considerable therapeutic effects against tissue nematode/cestode infections (visceral, ocular, neural, and cutaneous larva migrans, anisakiasis, trichinosis, hepatic and intestinal capillariasis, angiostrongyliasis, gnathostomiasis, gongylonemiasis, thelaziasis, dracunculiasis, cerebral and subcutaneous cysticercosis, and echinococcosis). Albendazole is also used for treatment of filarial infections (lymphatic filariasis, onchocerciasis, loiasis, mansonellosis, and dirofilariasis) alone or in combination with other drugs, such as ivermectin or diethylcarbamazine. Albendazole was tried even for treatment of trematode (fascioliasis, clonorchiasis, opisthorchiasis, and intestinal fluke infections) and protozoan infections (giardiasis, vaginal trichomoniasis, cryptosporidiosis, and microsporidiosis). These drugs are generally safe with few side effects; however, when they are used for prolonged time (>14-28 days) or even only 1 time, liver toxicity and other side reactions may occur. In hookworms, Trichuris trichiura, possibly Ascaris lumbricoides, Wuchereria bancrofti, and Giardia sp., there are emerging issues of drug resistance. It is of particular note that albendazole and mebendazole have been repositioned as promising anti-cancer drugs. These drugs have been shown to be active in vitro and in vivo (animals) against liver, lung, ovary, prostate, colorectal, breast, head and neck cancers, and melanoma. Two clinical reports for albendazole and 2 case reports for mebendazole have revealed promising effects of these drugs in human patients having variable types of cancers. However, because of the toxicity of albendazole, for example, neutropenia due to myelosuppression, if high doses are used for a prolonged time, mebendazole is currently more popularly used than albendazole in anti-cancer clinical trials.

Effects of Three-time Administration of a Supramolecular Complex of Praziquantel with Disodium Glycyrrhizinate on Trematode Opisthorchis felineus in Hamsters

BACKGROUND

Praziquantel (PZQ) is the most commonly used anthelmintic drug for treating trematodiases. It was shown here that PZQ in complex with disodium glycyrrhizinate (PZQ-Na₂GA, in the 1:10 ratio) has higher bioavailability than PZQ alone. Our aim was to determine the effects of three-time administration of PZQ-Na₂GA in an experimental opisthorchiasis felinea model.

METHODS

The PZQ-Na₂GA complex (1:10) at a 400 mg/kg dose (meaning 36.4 mg/kg PZQ) was administered to Opisthorchis felineus-infected hamsters three times under a "9:00 am-6:00 pm-9:00 am" regimen (PZQ-Na₂GA × 3). Effects of treatment were assessed as a reduction of helminth load in the hamsters and as changes in physiological, hematological, and blood biochemical parameters. The helminths extracted from the liver of the hamsters that received PZQ-Na₂GA thrice were assayed for sensitivity to PZQ in vitro.

RESULTS

PZQ-Na₂GA × 3 reduced the number of O. felineus helminths in the liver by 87%, which is 30% better than a previously reported effect of one-time administration of the complex. Meanwhile, relative weights of the liver and thymus diminished, and some hematological parameters improved. The helminths extracted from the hamsters 1 month after the PZQ-Na₂GA × 3 treatment showed elevated sensitivity to PZQ, as determined in vitro.

CONCLUSION

Compared with previously published data on the effectiveness of various drugs in experimental opisthorchiasis felinea, PZQ-Na₂GA × 3 exerts the most potent anthelmintic effect. In addition, PZQ-Na₂GA × 3 improves physiological status of O. felineus-infected hamsters and sensitizes the surviving parasites to subsequent PZQ treatment.

Food handlers: an important reservoir of protozoans and helminth parasites of public health importance

Food handlers plays a primary role in the transmission of pathogenically important protozoans and helminth parasites. This study was aimed to evaluate the prevalence of intestinal pathogenic protozoans and helminth parasites among food handlers in and around University of Malakand, Lower Dir, Pakistan. Stool samples were collected from 642 food handlers (all of male) in a cross-sectional study from January to November, 2017. Wet Mount Techniques and concentration methods by using salt and formol-ether solutions. Three hundred and eighty four cases (59.8%) were found infected with one more parasites. Most of the individuals were found infected with helminth (47.6%) as compared to intestinal protozoans (0.93%). Seventy two cases (11.2%) of the cases presented mixed infection with both intestinal protozoan and helminth parasites. The order of prevalence for intestinal helminth was Ancylostoma duodenale (n = 258, 40.1%), followed by Taeniasa ginata (n=96, 14.9%) Ascaris lumbricoides (n = 54, 8.40%) and Trichuris trichura (n=30, 4.60%). For intestinal protozoa, Entamoeba histolytica/dispar (n = 36, 5.64%) was the only protozoan detected. Mono-parasitism was higher than poly-parasitism. Family size income and education level were the factors significantly (P<0.05) associated in the parasites prevalence. Current research showed that IPIs are primarily the foodborne pathogens still an important public health problem in Pakistan. Effective control programs on parasitic diseases transfer and their associated factors are recommended.

Dose prediction for repurposing nitazoxanide in SARS-CoV-2 treatment or chemoprophylaxis

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been declared a global pandemic and urgent treatment and prevention strategies are needed. Nitazoxanide, an anthelmintic drug, has been shown to exhibit in vitro activity against SARS-CoV-2. The present study used physiologically based pharmacokinetic (PBPK) modelling to inform optimal doses of nitazoxanide capable of maintaining plasma and lung tizoxanide exposures above the reported SARS-CoV-2 EC90 .

METHODS

A whole-body PBPK model was validated against available pharmacokinetic data for healthy individuals receiving single and multiple doses between 500 and 4000 mg with and without food. The validated model was used to predict doses expected to maintain tizoxanide plasma and lung concentrations above the EC90 in >90% of the simulated population. PopDes was used to estimate an optimal sparse sampling strategy for future clinical trials.

RESULTS

The PBPK model was successfully validated against the reported human pharmacokinetics. The model predicted optimal doses of 1200 mg QID, 1600 mg TID and 2900 mg BID in the fasted state and 700 mg QID, 900 mg TID and 1400 mg BID when given with food. For BID regimens an optimal sparse sampling strategy of 0.25, 1, 3 and 12 hours post dose was estimated.

CONCLUSION

The PBPK model predicted tizoxanide concentrations within doses of nitazoxanide already given to humans previously. The reported dosing strategies provide a rational basis for design of clinical trials with nitazoxanide for the treatment or prevention of SARS-CoV-2 infection. A concordant higher dose of nitazoxanide is now planned for investigation in the seamless phase I/IIa AGILE trial.

Crystal Structure and Structure-Based Discovery of Inhibitors of the Nematode Chitinase CeCht1

Nematode chitinases play crucial roles in various processes of the nematode lifecycle, including hatching, molting, and reproduction. Small-molecule inhibitors of nematode chitinases have shown promise for controlling nematode pests. However, the lack of structural information makes it a challenge to develop nematicides targeting nematode chitinases. Here, we report the first crystal structure of a representative nematode chitinase, that of CeCht1 from the model nematode Caenorhabditis elegans, to a 1.7 Å resolution. CeCht1 is a highly conserved chitinase among nematodes, and structural comparison with other chitinases revealed that CeCht1 has a classical TIM-barrel fold with some subtle structural differences in the substrate-binding cleft. Benefiting from the obtained crystal structure, we identified a series of novel inhibitors by hierarchical virtual screening. Analysis of the structure-activity relationships of these compounds provided insight into their interactions with the enzyme active site, which may inform future work in improving the potencies of their inhibitory activities. This work gives an insight into the structural features of nematode chitinases and provides a solid basis for the development of inhibitors.

Modeling the Interruption of the Transmission of Soil-Transmitted Helminths Infections in Kenya: Modeling Deworming, Water, and Sanitation Impacts

Kenya, just like other countries with endemic soil-transmitted helminths (STH), has conducted regular mass drug administration (MDA) program for the last 5 years among school aged children as a way to reduce STH infections burden in the country. However, the point of interruption of transmission of these infections still remains unclear. In this study, we developed and analyzed an age structured mathematical model to predict the elimination period (i.e., time taken to interrupt STH transmission) of these infections in Kenya. The study utilized a deterministic age structured model of the STH population dynamics under a regular treatment program. The model was applied to three main age groups: pre-school age children (2-4 years), school age children (5-14 years), and adult populations (≥15 years) and compared the impact of two interventions on worm burden and elimination period. The model-simulated results were compared with the 5 year field data from the Kenyan deworming program for all the three types of STH (Ascaris lumbricoides, Trichuris trichiura, and hookworm). The model demonstrated that the reduction of worm burden and elimination period depended heavily on four parameter groups; drug efficacy, number of treatment rounds, MDA and water, sanitation and hygiene (WASH) coverage. The analysis showed that for STH infections to be eliminated using MDA alone in a short time period, 3-monthly MDA plan is desired. However, complementation of MDA with WASH at an optimal (95%) coverage level was most effective. These results are important to the Kenyan STH control program as it will guide the recently launched Breaking Transmission Strategy.

Recombinant Paraprobiotics as a New Paradigm for Treating Gastrointestinal Nematode Parasites of Humans

Gastrointestinal nematodes (GINs) of humans, e.g., hookworms, negatively impact childhood growth, cognition, nutrition, educational attainment, income, productivity, and pregnancy. Hundreds of millions of people are targeted with mass drug administration (MDA) of donated benzimidazole anthelmintics.

Gastrointestinal nematodes (GINs) of humans, e.g., hookworms, negatively impact childhood growth, cognition, nutrition, educational attainment, income, productivity, and pregnancy. Hundreds of millions of people are targeted with mass drug administration (MDA) of donated benzimidazole anthelmintics. However, benzimidazole efficacy against GINs is suboptimal, and reduced/low efficacy has been seen. Developing an anthelmintic for human MDA is daunting: it must be safe, effective, inexpensive, stable without a cold chain, and massively scalable. Bacillus thuringiensis crystal protein 5B (Cry5B) has anthelmintic properties that could fill this void. Here, we developed an active pharmaceutical ingredient (API) containing B. thuringiensis Cry5B compatible with MDA. We expressed Cry5B in asporogenous B. thuringiensis during vegetative phase, forming cytosolic crystals. These bacteria with cytosolic crystals (BaCC) were rendered inviable (inactivated BaCC [IBaCC]) with food-grade essential oils. IBaCC potency was validated in vitro against nematodes. IBaCC was also potent in vivo against human hookworm infections in hamsters. IBaCC production was successfully scaled to 350 liters at a contract manufacturing facility. A simple fit-for-purpose formulation to protect against stomach digestion and powdered IBaCC were successfully made and used against GINs in hamsters and mice. A pilot histopathology study and blood chemistry workup showed that five daily consecutive doses of 200 mg/kg body weight Cry5B IBaCC (the curative single dose is 40 mg/kg) was nontoxic to hamsters and completely safe. IBaCC is a safe, inexpensive, highly effective, easy-to-manufacture, and scalable anthelmintic that is practical for MDA and represents a new paradigm for treating human GINs.

A Machine Learning Strategy for Drug Discovery Identifies Anti-Schistosomal Small Molecules

Schistosomiasis is a chronic and painful disease of poverty caused by the flatworm parasite Schistosoma. Drug discovery for antischistosomal compounds predominantly employs in vitro whole organism (phenotypic) screens against two developmental stages of Schistosoma mansoni, post-infective larvae (somules) and adults. We generated two rule books and associated scoring systems to normalize 3898 phenotypic data points to enable machine learning. The data were used to generate eight Bayesian machine learning models with the Assay Central software according to parasite’s developmental stage and experimental time point (≤24, 48, 72, and >72 h). The models helped predict 56 active and nonactive compounds from commercial compound libraries for testing. When these were screened against S. mansoni in vitro, the prediction accuracy for active and inactives was 61% and 56% for somules and adults, respectively; also, hit rates were 48% and 34%, respectively, far exceeding the typical 1–2% hit rate for traditional high throughput screens.

Population Pharmacokinetics and Exposure-Response Analysis of Tribendimidine To Improve Treatment for Children with Hookworm Infection

Tribendimidine has been successful in treating hookworm infections and may serve as an alternative to albendazole should resistance arise. Our aims were to (i) characterize the pharmacokinetics (PK) of tribendimidine's primary metabolite, deacetylated amidantel (dADT), and secondary metabolite, acetylated derivative of amidantel (adADT), in school-aged children and adolescents, (ii) link exposure to efficacy against hookworm, and (iii) evaluate whether tribendimidine pharmacotherapy in children could be further improved. First, a population PK model was developed based on dried-blood-spot samples collected from 155 school-aged children and adolescents with hookworm infections, following tribendimidine doses ranging from 100 to 400 mg. Second, an exposure-response analysis was conducted to link the active metabolite dADT to cure rates (CRs) and egg reduction rates (ERRs). Third, simulations were performed to identify a treatment strategy associated with >90% CRs. A two-compartmental model with transit compartments describing observed delay in absorption adequately described PK data of dADT and adADT. Allometric scaling was included to account for growth and development. The absorption rate was 56% lower with 200-mg tablets than with 50-mg tablets, while the extent of absorption remained unaffected. The identified Emax models linking dADT exposure to ERRs and CRs showed shallow curves, as increasing exposure led to marginal efficacy increase. Combination therapy should be considered, as a 12-fold-higher dose would be needed to achieve 95% ERRs and CRs >90% with tribendimidine alone. Further studies are warranted to evaluate safety of higher tribendimidine doses and combination therapies with other anthelmintic agents to improve treatment strategy for children with hookworm infection.

Pharmacometric Analysis of Tribendimidine Monotherapy and Combination Therapies To Achieve High Cure Rates in Patients with Hookworm Infections

In the treatment of hookworm infections, pharmacotherapy has been only moderately successful and drug resistance is a threat. Therefore, novel treatment options including combination therapies should be considered, in which tribendimidine could play a role. Our aims were to (i) characterize the pharmacokinetics of tribendimidine's metabolites in adolescents receiving tribendimidine monotherapy or in combination with ivermectin or oxantel pamoate, (ii) evaluate possible drug-drug interactions (DDI), (iii) link exposure to response, and (iv) identify a treatment strategy associated with high efficacy, i.e., >90% cure rates (CRs), utilizing model-based simulations. A population pharmacokinetic model was developed for tribendimidine's primary and secondary metabolites, dADT and adADT, in 54 hookworm-positive adolescents, with combination therapy evaluated as a possible covariate. Subsequently, an exposure-response analysis was performed utilizing CRs as response markers. Simulations were performed to identify a treatment strategy to achieve >90% CRs. A two-compartmental model best described metabolite disposition. No pharmacokinetic DDI was identified with ivermectin or oxantel pamoate. All participants receiving tribendimidine plus ivermectin were cured. For the monotherapy arm and the arm including the combination with oxantel pamoate, E _max models adequately described the correlation between dADT exposure and probability of being cured, with required exposures to achieve 50% of maximum effect of 39.6 and 15.6 nmol/ml·h, respectively. Based on our simulations, an unrealistically high monotherapy tribendimidine dose would be necessary to achieve CRs of >90%, while combination therapy with ivermectin would meet this desired target product profile. Further clinical studies should be launched to develop this combination for the treatment of hookworm and other helminth infections.

Intestinal Parasites Infection in Children with Cancer in Ahvaz, Southwest Iran

Background

Infection with intestinal parasites is widespread worldwide, especially in developing countries. Intestinal parasites are known as one of the leading causes of diarrhea in both immunocompetent and immunocompromised subjects, but cancer patients are highly susceptible to contamination, and it can be deadly for them. This study aimed to estimate the prevalence of intestinal parasites in immunocompromised patients in Ahvaz. Material and Methods. In this descriptive cross-sectional pilot case-control study, fecal samples were collected from 52 children with malignancies hospitalized in Baqaei2 hospital in Ahvaz. A questionnaire including demographic information, type of cancer, type of gastrointestinal symptoms, and laboratory diagnosis was completed for each patient. The collected specimens were examined by direct smear, Logul staining, and concentration.

Result

The 52 stool samples were collected, 46% were female and 54% male. The age range of children enrolled in the study was from 4 months to 16 years. Of these stool samples, 38.38% were infected with a variety of parasitic intestinal infections (helminths and protozoa). In this study, protozoan parasites, Blastocystis (23%), Chilomastix mesnili (1.92%), Endolimax nana (7.7%), and Entamoeba coli (1.92%), and helminth infection, Strongyloides stercoralis (3.84%), were observed and statistical analysis showed that there was a significant relationship between gastrointestinal symptoms and parasitic infection in children with cancer.

Conclusion

Blastocystis and Endolimax nana are the most prevalent gastrointestinal parasitic protozoans that infect individuals admitted to Baqaei2 Hospital of Ahvaz, Iran. Since parasitic intestinal infections in immunocompromised patients lead to fatal diarrhea, children with parasitic infections must be carefully identified and treated.

Model-based spatial-temporal mapping of opisthorchiasis in endemic countries of Southeast Asia

Opisthorchiasis is an overlooked danger to Southeast Asia. High-resolution disease risk maps are critical but have not been available for Southeast Asia. Georeferenced disease data and potential influencing factor data were collected through a systematic review of literatures and open-access databases, respectively. Bayesian spatial-temporal joint models were developed to analyze both point- and area-level disease data, within a logit regression in combination of potential influencing factors and spatial-temporal random effects. The model-based risk mapping identified areas of low, moderate, and high prevalence across the study region. Even though the overall population-adjusted estimated prevalence presented a trend down, a total of 12.39 million (95% Bayesian credible intervals [BCI]: 10.10–15.06) people were estimated to be infected with O. viverrini in 2018 in four major endemic countries (i.e., Thailand, Laos, Cambodia, and Vietnam), highlighting the public health importance of the disease in the study region. The high-resolution risk maps provide valuable information for spatial targeting of opisthorchiasis control interventions.

The Prevalence of Intestinal Parasitic Infections Among Kosovar and Serbian School-children in Kosovo

The aim of this study was to estimate the prevalence and distribution of species of intestinal parasites in the Balkans on the example of Kosovar and Serbian residents from the region of Gnjilane ineastern Kosovo,where the epidemiology of intestinal parasitic infections remains unknown. Parasitological examination of stools pecimens was performed in 2017 and 2018. Stool samples were collected from asymptomatic school-children aged 6–17 years: 530 Kosovars from the municipality of Kaçanik and310 Serbs from the municipalities of Kamenica and Strpce. Each patient provided two stool samples collected every second day,fixed in SAF preservative and 70 % spiritus vini, transported to the Department of Epidemiology and Tropical Medicine at the Military Institute of Medicine in Poland,and tested by light microscopy using three diagnostic methods: directs mearin Lugol’s solution,decantation in distilled water, and Fülleborn’s flotation. A total of 101 Kosovar children (19.1 % of the study group)were found to be infected with intestinal parasites: nematodes (n=20), cestodes (n=2), trematodes (n=2), and protozoa (n=79). Only 13 Serbian children (4.2 %) were found to beinfected with nematodes (n=4),cestodes (n=3),and protozoa (n=6). Giardia intestinalis was themost prevalent intestinal parasite in both groups (14,9 % vs. 1.9 % children). The prevalence ofasymptomatic parasitic infections was significantly higher in Kosovars in comparison to the Serbsliving in the same region of eastern Kosovo. This fact shows that there may be significant differencesin the quality of health care and sanitation as well as feed hygiene between these two communities.

Anthelmintic Activity of Yeast Particle-Encapsulated Terpenes

Soil-transmitted nematodes (STN) infect 1-2 billion of the poorest people worldwide. Only benzimidazoles are currently used in mass drug administration, with many instances of reduced activity. Terpenes are a class of compounds with anthelmintic activity. Thymol, a natural monoterpene phenol, was used to help eradicate hookworms in the U.S. South circa 1910. However, the use of terpenes as anthelmintics was discontinued because of adverse side effects associated with high doses and premature stomach absorption. Furthermore, the dose-response activity of specific terpenes against STNs has been understudied. Here we used hollow, porous yeast particles (YPs) to efficiently encapsulate (>95%) high levels of terpenes (52% w/w) and evaluated their anthelmintic activity on hookworms (Ancylostoma ceylanicum), a rodent parasite (Nippostrongylus brasiliensis), and whipworm (Trichuris muris). We identified YP-terpenes that were effective against all three parasites. Further, YP-terpenes overcame albendazole-resistant Caenorhabditis elegans. These results demonstrate that terpenes are broad-acting anthelmintics. Terpenes are predicted to be extremely difficult for parasites to resist, and YP encapsulation provides water-suspendable terpene materials without surfactants and sustained terpene release that could lead to the development of formulations for oral delivery that overcome fast absorption in the stomach, thus reducing dosage and toxic side effects.

Determining the Impact of a School-Based Health Education Package for Prevention of Intestinal Worm Infections in the Philippines: Protocol for a Cluster Randomized Intervention Trial

Background

Repeated mass drug administration (MDA) of antihelminthics to at-risk populations is still the main strategy for the control of soil-transmitted helminth (STH) infections. However, MDA, as a stand-alone intervention, does not prevent reinfection. Accordingly, complementary measures to prevent STH reinfection, such as health education and improved sanitation, as part of an integrated control approach, are required to augment the effectiveness of MDA for optimal efficiency and sustainability.

Objective

The aim of this study is to determine the impact and generalizability of a school-based health education package entitled The Magic Glasses for STH prevention in the Philippines.

Methods

We conducted a cluster randomized controlled intervention trial, involving 2020 schoolchildren aged 9-10 years, in 40 schools in Laguna Province, Philippines, to evaluate the impact of the school-based health education package for the prevention of STHs. The trial was conducted over the course of 1 year (June 2016 to July 2017). A total of 20 schools were randomly assigned to the intervention arm, in which The Magic Glasses Philippines health education package was delivered with the standard health education activities endorsed by the Philippines Department of Health (DOH) and the Department of Education (DepEd). The other 20 schools comprised the control arm of the study, where the DOH/DepEd’s standard health education activities were done. At baseline, parasitological assessments and a knowledge, attitude, and practice survey were carried out in all schools. In addition, height, weight, and hemoglobin levels were obtained from each child (after parental consent), and their school attendance and academic performance in English and mathematics were accessed from the school records. The baseline and 2 follow-up surveys were completed using the same study measurements and quality-control assessments.

Results

Key results from this cluster randomized intervention trial will shed light on the impact that The Magic Glasses health education package will have against STH infections in schoolchildren in the province of Laguna, located on the Island of Luzon, in the Calabarzon Region of the Philippines.

Conclusions

The results of the trial will be used to assess the generalizability of the impact of The Magic Glasses health education package in different epidemiological and cultural settings, providing evidence for translation of this health education package into public health policy and practice in the Asian region and beyond.

Trial Registration

Australian New Zealand Clinical Trials Registry number ACTRN12616000508471; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=368849

International Registered Report Identifier (IRRID)

DERR1-10.2196/18419

Intestinal parasitosis, anaemia and risk factors among pre-school children in Tigray region, northern Ethiopia

BACKGROUND

Intestinal parasitic infections (IPIs) and anaemia are major health problems. This study assessed the prevalence of intestinal parasitic infections, anaemia and associated factors among pre-school children in rural areas of the Tigray region, northern Ethiopia.

METHODS

A community based cross-sectional study was conducted among 610 pre-school children in rural communities of Northern Ethiopia from June 2017 to August 2017. Stool specimens were examined for the presence of trophozoites, cysts, oocysts, and ova using direct, formal-ethyl acetate concentration, Kato-Katz, and Ziehl-Neelsen techniques. Haemoglobin was measured using a HemoCue spectrometer.

RESULTS

Among the 610 participating pre-school children in the study, the prevalence of IPIs and anaemia were 58% (95% conference interval (CI): 54.1-61.9%) and 21.6% (95% CI: 18.5-25.1%), respectively. Single, double, and triple parasitic infections were seen in 249 (41, 95% CI: 37-45%), 83 (14, 95% CI: 11-17%), and 22 (3.6, 95% CI: 2.4-5.4%) children, respectively. Of the seven intestinal parasitic organisms recorded from the participants, Entamoeba histolytica/dispar was the most prevalent 220 (36.1%) followed by Giardia lamblia 128 (20.1%), and Hymenolepis nana 102 (16.7%). Mixed infections were common among G. lamblia, E. histolytica/dispar and Cryptosporidium spp. oocyst. Intestinal parasitic infection prevalence increased from 47% in children aged 6-11 months to 66% in those aged 48-59 months; the prevalence ratio (PR) associated with a one-year increase in age was 1.08 (95% CI: 1.02-1.14, p = 0.009). Age-adjusted prevalence was higher in children who had been dewormed (PR = 1.2; 95% CI: 1.00-1.4, p = 0.045), and lower in households having two or more children aged under five (PR = 0.76, 95% CI: 0.61-0.95, p = 0.015). Anaemia rose from 28% in children aged 6-11 months to 43% in those aged 12-23 months, then fell continuously with age, reaching 7% in those aged 48-59 months. Age adjusted, anaemia was more prevalent in households using proper disposal of solid waste (PR = 1.5, 95% CI: 0.1-2.10, p = 0.009) while eating raw meat (PR = 0.49, 95% CI: 0.45-0.54, p = 0.000), any maternal education (PR = 0.64 95% CI: 0.52-0.79, p = 0.000), and household water treatment (PR = 0.75, 95% CI: 0.56-1.0, p = 0.044) were associated with lower prevalence of anaemia.

CONCLUSIONS

More than half of the children were infected with intestinal parasites, while anaemia prevalence was concentrated in the 12-23 month age group. This study has identified a number of potentially modifiable risk factors to address the significant prevalence of IPIs and anaemia in these children. Improvements in sanitation, clean water, hand hygiene, maternal education could address both short and long-term consequences of these conditions in this vulnerable population.

Dose prediction for repurposing nitazoxanide in SARS-CoV-2 treatment or chemoprophylaxis

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been declared a global pandemic by the World Health Organisation and urgent treatment and prevention strategies are needed. Many clinical trials have been initiated with existing medications, but assessments of the expected plasma and lung exposures at the selected doses have not featured in the prioritisation process. Although no antiviral data is currently available for the major phenolic circulating metabolite of nitazoxanide (known as tizoxanide), the parent ester drug has been shown to exhibit in vitro activity against SARS-CoV-2. Nitazoxanide is an anthelmintic drug and its metabolite tizoxanide has been described to have broad antiviral activity against influenza and other coronaviruses. The present study used physiologically-based pharmacokinetic (PBPK) modelling to inform optimal doses of nitazoxanide capable of maintaining plasma and lung tizoxanide exposures above the reported nitazoxanide 90% effective concentration (EC ₉₀ ) against SARS-CoV-2.

METHODS

A whole-body PBPK model was constructed for oral administration of nitazoxanide and validated against available tizoxanide pharmacokinetic data for healthy individuals receiving single doses between 500 mg SARS-CoV-2 4000 mg with and without food. Additional validation against multiple-dose pharmacokinetic data when given with food was conducted. The validated model was then used to predict alternative doses expected to maintain tizoxanide plasma and lung concentrations over the reported nitazoxanide EC ₉₀ in >90% of the simulated population. Optimal design software PopDes was used to estimate an optimal sparse sampling strategy for future clinical trials.

RESULTS

The PBPK model was validated with AAFE values between 1.01 SARS-CoV-2 1.58 and a difference less than 2-fold between observed and simulated values for all the reported clinical doses. The model predicted optimal doses of 1200 mg QID, 1600 mg TID, 2900 mg BID in the fasted state and 700 mg QID, 900 mg TID and 1400 mg BID when given with food, to provide tizoxanide plasma and lung concentrations over the reported in vitro EC ₉₀ of nitazoxanide against SARS-CoV-2. For BID regimens an optimal sparse sampling strategy of 0.25, 1, 3 and 12h post dose was estimated.

CONCLUSION

The PBPK model predicted that it was possible to achieve plasma and lung tizoxanide concentrations, using proven safe doses of nitazoxanide, that exceed the EC ₉₀ for SARS-CoV-2. The PBPK model describing tizoxanide plasma pharmacokinetics after oral administration of nitazoxanide was successfully validated against clinical data. This dose prediction assumes that the tizoxanide metabolite has activity against SARS-CoV-2 similar to that reported for nitazoxanide, as has been reported for other viruses. The model and the reported dosing strategies provide a rational basis for the design (optimising plasma and lung exposures) of future clinical trials of nitazoxanide in the treatment or prevention of SARS-CoV-2 infection.

National surveillance on soil-transmitted helminthiasis in the People's Republic of China

Soil-transmitted helminths (STHs) are widely distributed and remain a public health problem in the People's Republic of China. Altogether, 301 counties across 30 regions were investigated during the national surveillance on STHs carried out in 2016 based on the modified Kato-Katz thick smear method to examine faecal samples. A total of 305 081 people were investigated with 7 366 (2.4%) found to be infected. The infection rates were the following: hookworm 1.4%, Ascaris lumbricoides 0.8% and Trichuris trichiura 0.5%. Having established that the STHs infection rate is relatively low, it is time to move towards elimination. The national surveillance system is essential for providing basic data and formulation of useful control strategies towards achieving this goal.

Efficacy and safety of ascending dosages of albendazole against Trichuris trichiura in preschool-aged children, school-aged children and adults: A multi-cohort randomized controlled trial

BACKGROUND

The efficacy of the widely used albendazole against the soil-transmitted helminth Trichuris trichiura is limited; yet optimal doses, which may provide increased efficacy, have not been thoroughly investigated to date.

METHODS

A randomized-controlled trial was conducted in Côte d'Ivoire with preschool-aged children (PSAC), school-aged children (SAC), and adults infected with T. trichiura. Participants were randomly assigned (1:1:1:1) using computer-generated randomization. PSAC were randomized to 200 mg, 400 mg, 600 mg of albendazole or placebo. SAC and adults were randomized to 400 mg, 600 mg, 800 mg of albendazole or placebo. The primary outcome was cure rates (CRs) against trichuriasis. Secondary outcomes were T. trichiura egg reduction rates (ERRs), safety, CRs and ERRs against other soil-transmitted helminths. Outcome assessors and the trial statistician were blinded. Trial registration at ClinicalTrial.gov: NCT03527745.

FINDINGS

111 PSAC, 180 SAC, and 42 adults were randomized and 86, 172, and 35 provided follow-up stool samples, respectively. The highest observed CR among PSAC was 27·8% (95% CI: 9·7%-53·5%) in the 600 mg albendazole treatment arm. The most efficacious arm for SAC was 600 mg of albendazole showing a CR of 25·6% (95% CI: 13·5%-41·2%), and for adults it was 400 mg of albendazole with a CR of 55·6% (95% CI: 21·2%-86·3%). CRs and ERRs did not differ significantly among treatment arms and flat dose-responses were observed. 17·9% and 0·4% of participants reported any adverse event at 3 and 24 h follow-up, respectively.

INTERPRETATION

Albendazole shows low efficacy against T. trichiura in all populations and doses studied, though findings for PSAC and adults should be carefully interpreted as recruitment targets were not met. New drugs, treatment regimens, and combinations are needed in the management of T. trichiura infections.

FUNDING

Bill and Melinda Gates Foundation.

The Strongyloides stercoralis-hookworms association as a path to the estimation of the global burden of strongyloidiasis: A systematic review

TRIAL REGISTRATION

PROSPERO (registration code CRD42019131127).

Piloting a surveillance system to monitor the global patterns of drug efficacy and the emergence of anthelmintic resistance in soil-transmitted helminth control programs: a Starworms study protocol

To eliminate soil-transmitted helminth (STH) infections as a public health problem, the administration of benzimidazole (BZ) drugs to children has recently intensified. But, as drug pressure increases, the development of anthelmintic drug resistance (AR) becomes a major concern. Currently, there is no global surveillance system to monitor drug efficacy and the emergence of AR. Consequently, it is unclear what the current efficacy of the used drugs is and whether AR is already present. The aim of this study is to pilot a global surveillance system to assess anthelmintic drug efficacy and the emergence of AR in STH control programs. For this, we will incorporate drug efficacy trials into national STH control programs of eight countries (Bangladesh, Cambodia, Lao PDR, Vietnam, Ghana, Rwanda, Senegal and a yet to be defined country in the Americas). In each country, one trial will be performed in one program implementation unit to assess the efficacy of BZ drugs against STHs in school-aged children by faecal egg count reduction test. Stool samples will be collected before and after treatment with BZs for Kato-Katz analysis and preserved to purify parasite DNA. The presence and frequency of known single nucleotide polymorphisms (SNPs) in the β-tubulin genes of the different STHs will subsequently be assessed. This study will provide a global pattern of drug efficacy and emergence of AR in STH control programs. The results will provide complementary insights on the validity of known SNPs in the ß-tubulin gene as a marker for AR in human STHs as well as information on the technical and financial resources required to set up a surveillance system. Finally, the collected stool samples will be an important resource to validate different molecular technologies for the detection of AR markers or to identify novel potential molecular markers associated with AR in STH.

Effectiveness of Repeated Administration of Praziquantel with Disodium Glycyrrhizinate and Two Enantiomers of Praziquantel on Opisthorchis felineus (Rivolta, 1884)

BACKGROUND

Nowadays, it is still important to develop effective anti-opisthorchiasis agents. In this work, we tested a complex of praziquantel (PZQ) with a plant origin compound-disodium glycyrrhizinate-in the ratio 1:10 PZQ:Na₂GA, containing 11-fold less of the active ingredient. Our aim was to study various ways to treat trematode Opisthorchis felineus with this complex in vitro. Additionally, an in vitro comparison of the anthelmintic action was made among racemic-PZQ, (R)-PZQ, and (S)-PZQ on juvenile and adult maritae of O. felineus.

METHODS

Worms extracted from the hamsters were subjected to various regimens of administration of the complex: once a day for 3 days or three times within 1 day. Moreover, mature maritae and juvenile worms of O. felineus were subjected to the comparison the anthelmintic effectiveness of racemic-PZQ, (R)-PZQ, and (S)-PZQ.

RESULTS

The O. felineus maritae that received PZQ:Na₂GA (1:10) thrice within 1 day were most strongly affected by the drug. Their motility substantially decreased already on the second day after the last dose, and the percentage of live worms by the end of the experimental period was the lowest. These results indicate a cumulative anthelmintic effect of this substance under the regimen "three times within 1 day." For the first time, we report that among the three substances (racemic-PZQ and two enantiomers), (R)-PZQ has the highest anthelmintic activity, toward both juvenile and sexually mature maritae of O. felineus.

CONCLUSION

These findings suggest that the development of a supramolecular complex of (R)-PZQ with disodium glycyrrhizinate and administration of this complex three times within 1 day are promising approaches.

Searching for drugs for Chagas disease, leishmaniasis and schistosomiasis: a review

Chagas disease, leishmaniasis and schistosomiasis are neglected diseases (NDs) and are a considerable global challenge. Despite the huge number of people infected, NDs do not create interest from pharmaceutical companies because the associated revenue is generally low. Most of the research on these diseases has been conducted in academic institutions. The chemotherapeutic armamentarium for NDs is scarce and inefficient and better drugs are needed. Researchers have found some promising potential drug candidates using medicinal chemistry and computational approaches. Most of these compounds are synthetic but some are from natural sources or are semi-synthetic. Drug repurposing or repositioning has also been greatly stimulated for NDs. This review considers some potential drug candidates and provides details of their design, discovery and activity.

Efficacy of Anthelminthic Drugs and Drug Combinations Against Soil-transmitted Helminths: A Systematic Review and Network Meta-analysis

Background

Periodic mass distribution of benzimidazole anthelminthic drugs is the key strategy to control soil-transmitted helminths (STHs) globally. However, benzimidazoles have low efficacy against Trichuris trichiura, and there are concerns about benzimidazole resistance potentially emerging in humans. Therefore, identifying alternative drug regimens is a pressing priority. We present a systematic review and network meta-analysis comparing the efficacy of 21 different anthelminthic drug regimens, including standard, novel, and combination treatments.

Methods

We searched PubMed, Medline, Embase, Web of Science, and Cochrane databases and identified studies comparing anthelminthic treatments to each other or placebo. The outcomes calculated were relative risk (RR) of cure and difference in egg reduction rates (dERR). We used an automated generalized pairwise modeling framework to generate mixed treatment effects against a common comparator, the current standard treatment (single-dose albendazole).

Results

Our search identified 4876 studies, of which 114 were included in the meta-analysis. Results identified several drug combinations with higher efficacy than single-dose albendazole for T. trichiura, including albendazole-ivermectin (RR of cure, 3.22 [95% confidence interval {CI}, 1.84-5.63]; dERR, 0.97 [95% CI, .21-1.74]), albendazole-oxantel pamoate (RR, 5.07 [95% CI, 1.65-15.59]; dERR, 0.51 [95% CI, .50-.52]), mebendazole-ivermectin (RR, 3.37 [95% CI, 2.20-5.16]), and tribendimidine-oxantel pamoate (RR, 4.06 [95% CI, 1.30-12.64]).

Conclusions

There are several promising drug combinations that may enhance the impact of STH control programs on T. trichiura, without compromising efficacy against Ascaris lumbricoides and hookworm. We suggest further, large-scale trials of these drug combinations and consideration of their use in STH control programs where T. trichiura is present.

International Prospective Register of Systematic Reviews Registration

CRD42016050739.

Impact of the "BALatrine" Intervention on Soil-Transmitted Helminth Infections in Central Java, Indonesia: A Pilot Study

Many latrine campaigns in developing countries fail to be sustained because the introduced latrine is not appropriate to local socio-economic, cultural and environmental conditions, and there is an inadequate community health education component. We tested a low-cost, locally designed and constructed all-weather latrine (the “BALatrine”), together with community education promoting appropriate hygiene-related behaviour, to determine whether this integrated intervention effectively controlled soil-transmitted helminth (STH) infections. We undertook a pilot intervention study in two villages in Central Java, Indonesia. The villages were randomly allocated to either control or intervention with the intervention village receiving the BALatrine program and the control village receiving no program. STH-infection status was measured using the faecal flotation diagnostic method, before and eight months after the intervention. Over 8 months, the cumulative incidence of STH infection was significantly lower in the intervention village than in the control village: 13.4% vs. 27.5% (67/244 vs. 38/283, p < 0.001). The intervention was particularly effective among children: cumulative incidence 3.8% (2/53) for the intervention vs. 24.1% (13/54) for the control village (p < 0.001). The integrated BALatrine intervention was associated with a reduced incidence of STH infection. Following on from this pilot study, a large cluster-randomised controlled trial was commenced (ACTRN12613000523707).

High helminthic co-infection in tuberculosis patients with undernutritional status in northeastern Ethiopia

BACKGROUND

Tuberculosis and parasitosis are the widely distributed diseases in Ethiopia with the leading cause of mortality and morbidity, respectively. There has been no information on the status of co-infections of tuberculosis and parasitosis in Oromia Zone of Amhara Region and South Wollo, Ethiopia. Hence, this study primarily focuses on determining the status of tuberculosis and parasitosis co-infections and associated factors.

METHODS

The study was conducted in Oromia Special Zone of the Amhara Regional State and South Wollo Zone, northeastern Ethiopia from April 2015 to January 2017. Tuberculosis cases confirmed by health personnel at the health institutions were the source of the study sample. In a cross-sectional study 384 smear positive pulmonary and extra-pulmonary tuberculosis cases were recruited. Faecal specimens provided by the study participants were examined for parasitic co-infections using direct saline microscopic test, Kato-Katz and concentration techniques. Nutritional status was determined using body mass index and mid-upper arm circumferences. Data were analyzed using descriptive statistical methods and Pearson chi-square.

RESULTS

Tuberculosis and parasitosis co-infection prevalence was 10.8%, and the proportion of intestinal helminths accounted for 9.7% while intestinal protozoa accounted for 1.9%. Cases with single parasitic infection was 89.3% among co-infected individuals. Co-infection of both disease was not significantly associated with gender and age (P > 0.05). The prevalence of undernutrition was 58.6% as determined using body mass index and 73.0% as determined using mid-upper arm circumference with no significant association with gender. Among all forms of tuberculosis cases (384) screened for the study, the bacterial positivity was relatively more common in males (55.5%) than females (44.5%). Tuberculosis lymphadenitis was found to be the most prevalent (85.9%) form of extra-pulmonary tuberculosis with cervical adenopathy (75.3%) being the commonly existing disease.

CONCLUSIONS

The rate of helminthic co-infection is predominantly high than that of intestinal protozoa. Single parasitic co-infection was more common than double or multiple co-infections. Both body mass index and mid-upper arm circumference anthropometric parameters revealed greater risk of undernutrition in tuberculosis patients. Thus, screening and prompt treatment of parasites in tuberculosis patients and a support of nutritional supplementation for malnourished tuberculosis patients should be further studied which might enhance the disease treatment and minimize the risk of its complexity.

Soil-Transmitted Helminthiasis in Children from a Rural Community Taking Part in a Periodic Deworming Program in the Peruvian Amazon

Children in the Peruvian Amazon Basin are at risk of soil-transmitted helminths (STH) infections. This study aimed to determine the prevalence of STH infection in children from a rural Amazonian community of Peru and to elucidate epidemiological risk factors associated with its perpetuation while on a school-based deworming program with mebendazole. Stool samples of children aged 2-14 years and their mothers were analyzed through direct smear analysis, Kato-Katz, spontaneous sedimentation in tube, Baermann's method, and agar plate culture. A questionnaire was administered to collect epidemiological information of interest. Among 124 children, 25.8% had one or more STH. Individual prevalence rates were as follows: Ascaris lumbricoides, 16.1%; Strongyloides stercoralis, 10.5%; hookworm, 1.6%; and Trichuris trichiura, (1.6%). The prevalence of common STH (A. lumbricoides, T. trichiura, and hookworm) was higher among children aged 2-5 years than older children (31.6% versus 12.8%; P = 0.01). In terms of sanitation deficits, walking barefoot was significantly associated with STH infection (OR = 3.28; CI 95% = 1.11-12.07). Furthermore, STH-infected children more frequently had a mother who was concomitantly infected by STH than the non-STH-infected counterpart (36.4% versus 14.1%, P = 0.02). In conclusion, STH infection is highly prevalent in children from this Amazonian community despite routine deworming. Institutional health policies may include hygiene and sanitation improvements and screening/deworming of mothers to limit the dissemination of STH. Further studies are needed to address the social and epidemiological mechanics perpetuating these infections.

Therapeutic efficacy of albendazole against soil-transmitted helminthiasis in children measured by five diagnostic methods

Background

Preventive chemotherapy (PC) with benzimidazole drugs is the backbone of soil-transmitted helminth (STH) control programs. Over the past decade, drug coverage has increased and with it, the possibility of developing anthelmintic resistance. It is therefore of utmost importance to monitor drug efficacy. Currently, a variety of novel diagnostic methods are available, but it remains unclear whether they can be used to monitor drug efficacy. In this study, we compared the efficacy of albendazole (ALB) measured by different diagnostic methods in a head-to-head comparison to the recommended single Kato-Katz.

Methods

An ALB efficacy trial was performed in 3 different STH-endemic countries (Ethiopia, Lao PDR and Tanzania), each with a different PC-history. During these trials, stool samples were evaluated with Kato-Katz (single and duplicate), Mini-FLOTAC, FECPAK^G2, and qPCR. The reduction rate in mean eggs per gram of stool (ERR) and mean genome equivalents / ml of DNA extract (GERR) were calculated to estimate drug efficacy.

Principal findings and conclusions

The results of the efficacy trials showed that none of the evaluated diagnostic methods could provide reduction rates that were equivalent to a single Kato-Katz for all STH. However, despite differences in clinical sensitivity and egg counts, they agreed in classifying efficacy according to World Health Organization (WHO) guidelines. This demonstrates that diagnostic methods for assessing drug efficacy should be validated with their intended-use in mind and that other factors like user-friendliness and costs will likely be important factors in driving the choice of diagnostics. In addition, ALB efficacy against STH infections was lower in sites with a longer history of PC. Yet, further research is needed to identify factors that contribute to this finding and to verify whether reduced efficacy can be associated with mutations in the β-tubulin gene that have previously been linked to anthelmintic resistance.

Trial registration

ClinicalTrials.gov NCT03465488.

During the last decade, the scale of deworming programs that aim to eliminate the morbidity caused by intestinal worms has increased to a level that is unprecedented in history. It is therefore of utmost importance to monitor any change in therapeutic efficacy that may arise from emerging drug resistance. Currently, a variety of novel methods have been described, but it remains unclear whether they can be used for monitoring drug efficacy. We applied different diagnostic methods to measure the efficacy of a commonly administered drug in deworming programs in 3 countries with different historical exposure to deworming programs. Compared to the standard diagnostic method, all diagnostic methods revealed good agreement in classifying the therapeutic efficacy according to World Health Organization guidelines, despite clear differences in diagnostic performance. We also noticed that the drug efficacy was lower in countries where drug pressure has been high. However, more research is necessary to identify factors that explain this variation in drug efficacy, including but not limited to the frequency in mutations in genes that are known to be linked with anthelmintic resistance.

Expanding the Biological Application of Fluorescent Benzothiadiazole Derivatives: A Phenotypic Screening Strategy for Anthelmintic Drug Discovery Using Caenorhabditis elegans

The current methodologies used to identify promising new anthelmintic compounds rely on subjective microscopic examination of worm motility or involve genetic modified organisms. We describe a new methodology to detect worm viability that takes advantage of the differential incorporation of the fluorescent molecular marker propidium iodide and the 2,1,3-benzothiadiazole core, which has been widely applied in light technology. The new assay developed could be validated using the "Pathogen Box" library. By use of this bioassay, it was possible to identify three molecules with activity against Caenorhabditis elegans that were previously described as effective in in vitro assays against other pathogens, such as Schistosoma mansoni, Mycobacterium tuberculosis, and Plasmodium falciparum, accelerating the identification of molecules with anthelmintic potential. The current fluorescence-based bioassay may be used for assessing C. elegans viability. The described methodology replaces the subjectivity of previous assays and provides an enabling technology that is useful for rapid in vitro screens of both natural and synthetic compound libraries. It is expected that the results obtained from these robust in vitro screens would select the most effective compounds for follow-up in vivo experimentation with pathogenic helminths.

The major secreted protein of the whipworm parasite tethers to matrix and inhibits interleukin-13 function

Infection by soil transmitted parasitic helminths, such as Trichuris spp, are ubiquitous in humans and animals but the mechanisms determining persistence of chronic infections are poorly understood. Here we show that p43, the single most abundant protein in T. muris excretions/secretions, is non-immunogenic during infection and has an unusual sequence and structure containing subdomain homology to thrombospondin type 1 and interleukin (IL)−13 receptor (R) α2. Binding of p43 to IL-13, the key effector cytokine responsible for T. muris expulsion, inhibits IL-13 function both in vitro and in vivo. Tethering of p43 to matrix proteoglycans presents a bound source of p43 to facilitate interaction with IL-13, which may underpin chronic intestinal infection. Our results suggest that exploiting the biology of p43 may open up new approaches to modulating IL-13 function and control of Trichuris infections.

In the study, the authors identify a protein excreted by the parasite Trichuris muris, p43, which can modulate IL-13 function, a key cytokine involved in host protection. These data suggest that p43 may be a novel therapeutic target for both whipworm infections and IL13 mediated pathologies.