Helminth infections: the great neglected tropical diseases

An unusual case of gallbladder ascariasis in pregnancy

Gallbladder ascariasis in pregnancy presents with protracted nausea and vomiting.

Gastrointestinal Helminthic Infection among the Population in Northern Thailand

PURPOSE

Gastrointestinal (GI) helminthic infections pose substantial public health threat, particularly in northern Thailand, with a heightened concern in Nan province. This study aims to evaluate the prevalence of GI helminthic infections in Nan province and identify associated risk factors in local population.

METHODS

A cross-sectional survey was conducted in 2022. Fecal specimens were collected and examined using Kato-Katz technique and Formalin Ethyl-Acetate Concentration Technique (FECT). Univariate analysis employed the Chi-square test to explore correlations, while logistic regression was defined risk factors associated with parasite infections.

RESULTS

Among 739 individuals surveyed, 14.34% were revealed GI helminthic infections. Notably, infection rates were higher in males (20.40%) compared to females (8.95%), with a notable prevalence among individuals aged ≥ 60 (17.78%) and high infection rate was demonstrated in Kiew Chan village (21.67%). The most commonly detected helminths were minute intestinal flukes (MIFs) (10.01%) and Capillaria spp. (3.11%). Males were significantly associated with GI helminthic infections, while individuals aged 40-49 and aged 50-59 commonly displayed of parasite infections. Additionally, Kiew Chan village exhibited a significant association with GI helminthic infections, followed by Sop Puen village. Furthermore, fecal specimens of 13 rodent specimens were frequency revealed Strongyloides spp. (92.30%) and mostly exposed Ancylostoma caninum (41.93%) among 93 canines.

CONCLUSION

These findings highlight the imperative for immediate public health interventions in Nan province and analogous areas in northern Thailand. Implementing strategies to enhance sanitation infrastructure and promote hygiene education can significantly contribute for reducing the prevalence of GI helminthic infections and improve overall community health.

Helminth infection driven gastrointestinal hypermotility is independent of eosinophils and mediated by alterations in smooth muscle instead of enteric neurons

Intestinal helminth infection triggers a type 2 immune response that promotes a 'weep-and sweep' response characterised by increased mucus secretion and intestinal hypermotility, which function to dislodge the worm from its intestinal habitat. Recent studies have discovered that several other pathogens cause intestinal dysmotility through major alterations to the immune and enteric nervous systems (ENS), and their interactions, within the gastrointestinal tract. However, the involvement of these systems has not been investigated for helminth infections. Eosinophils represent a key cell type recruited by the type 2 immune response and alter intestinal motility under steady-state conditions. Our study aimed to investigate whether altered intestinal motility driven by the murine hookworm, Nippostrongylus brasiliensis, infection involves eosinophils and how the ENS and smooth muscles of the gut are impacted. Eosinophil deficiency did not influence helminth-induced intestinal hypermotility and hypermotility did not involve gross structural or functional changes to the ENS. Hypermotility was instead associated with a dramatic increase in smooth muscle thickness and contractility, an observation that extended to another rodent nematode, Heligmosomoides polygyrus. In summary our data indicate that, in contrast to other pathogens, helminth-induced intestinal hypermotility is driven by largely by myogenic, rather than neurogenic, alterations with such changes occurring independently of eosinophils. (<300 words).

Exploring extracellular vesicles in zoonotic helminth biology: implications for diagnosis, therapeutic and delivery

Extracellular vesicles (EVs) have emerged as key intercellular communication and pathogenesis mediators. Parasitic organisms' helminths, cause widespread infections with significant health impacts worldwide. Recent research has shed light on the role of EVs in the lifecycle, immune evasion, and disease progression of these parasitic organisms. These tiny membrane-bound organelles including microvesicles and exosomes, facilitate the transfer of proteins, lipids, mRNAs, and microRNAs between cells. EVs have been isolated from various bodily fluids, offering a potential diagnostic and therapeutic avenue for combating infectious agents. According to recent research, EVs from helminths hold great promise in the diagnosis of parasitic infections due to their specificity, early detection capabilities, accessibility, and the potential for staging and monitoring infections, promote intercellular communication, and are a viable therapeutic tool for the treatment of infectious agents. Exploring host-parasite interactions has identified promising new targets for diagnostic, therapy, and vaccine development against helminths. This literature review delves into EVS's origin, nature, biogenesis, and composition in these parasitic organisms. It also highlights the proteins and miRNAs involved in EV release, providing a comprehensive summary of the latest findings on the significance of EVs in the biology of helminths, promising targets for therapeutic and diagnostic biomarkers.

Potential of extracellular vesicles in the pathogenesis, diagnosis and therapy for parasitic diseases

Parasitic diseases have a significant impact on human and animal health, representing a major hazard to the public and causing economic and health damage worldwide. Extracellular vesicles (EVs) have long been recognized as diagnostic and therapeutic tools but are now also known to be implicated in the natural history of parasitic diseases and host immune response modulation. Studies have shown that EVs play a role in parasitic disease development by interacting with parasites and communicating with other types of cells. This review highlights the most recent research on EVs and their role in several aspects of parasite-host interactions in five key parasitic diseases: Chagas disease, malaria, toxoplasmosis, leishmaniasis and helminthiases. We also discuss the potential use of EVs as diagnostic tools or treatment options for these infectious diseases.

Th2-biased immune responses to body migrating Ascaris larvae in primary infection are associated with pathology but not protection

Helminth infections lead to an overdispersion of the parasites in humans as well as in animals. We asked whether early immune responses against migrating Ascaris larvae are responsible for the unequal distribution of worms in natural host populations and thus investigated a susceptible versus a resistant mouse strain. In mice, the roundworm larvae develop until the lung stage and thus early anti-Ascaris immune responses against the migrating larvae in the liver and lung can be deciphered. Our data show that susceptible C57BL/6 mice respond to Ascaris larval migration significantly stronger compared to resistant CBA mice and the anti-parasite reactivity is associated with pathology. Increased eosinophil recruitment was detected in the liver and lungs, but also in the spleen and peritoneal cavity of susceptible mice on day 8 post infection compared to resistant mice. In serum, eosinophil peroxidase levels were significantly higher only in the susceptible mice, indicating functional activity of the recruited eosinophils. This effect was associated with an increased IL-5/IL-13 production by innate lymphoid cells and CD4+ T cells and a pronounced type 2 macrophage polarization in the lungs of susceptible mice. Furthermore, a comparison of wildtype BALB/c and eosinophil-deficient dblGATA-1 BALB/c mice showed that eosinophils were not essential for the early control of migrating Ascaris larvae. In conclusion, in primary infection, a strong local and systemic type 2 immune response during hepato-tracheal helminth larval migration is associated with pathology rather than protection.

Unraveling new players in helminth pathology: extracellular vesicles from Fasciola hepatica and Dicrocoelium dendriticum exert different effects on hepatic stellate cells and hepatocytes

Fasciola hepatica and Dicrocoelium dendriticum are parasitic trematodes residing in the bile ducts of mammalian hosts, causing, in some cases, impairment of liver function and hepatic fibrosis. Previous studies have shown that extracellular vesicles released by F. hepatica (FhEVs) and D. dendriticum (DdEVs) induce a distinct phenotype in human macrophages, but there is limited information on the effect of parasitic EVs on liver cells, which interact directly with the worms in natural infections. In this study, we isolated FhEVs and DdEVs by size exclusion chromatography and labeled them with a lipophilic fluorescent dye to analyze their uptake by human hepatic stellate cells (HSC) and hepatocytes, important cell types in liver pathology, using synthetic liposomes as internal labeling and uptake control. We analyzed EV uptake and the proteome profiles after the treatment with EVs for both cell types. Our results reveal that EVs establish unique and specific interactions with stellate cells and hepatocytes, suggesting a different role of EVs derived from each parasite, depending on the migration route to reach their final niche. FhEVs have a cytostatic effect on HSCs, but induce the extracellular matrix secretion and elicit anti-inflammatory responses in hepatocytes. DdEVs have a more potent anti-proliferative effect than FhEVs and trigger a global inflammatory response, increasing the levels of NF-κB and other inflammatory mediators in both cell types. These interactions may have a major influence on the progression of the disease, serving to generate conditions that may favor the establishment of the helminths in the host.

Factors associated with hookworm and Schistosoma mansoni infections among school-aged children in Mayuge district, Uganda

BACKGROUND

Hookworm infection and schistosomiasis are two of sub-Saharan Africa's most common neglected tropical diseases. An annual mass drug administration (MDA) program against schistosomiasis and soil-transmitted helminths (STHs), including hookworm, has been implemented in Mayuge district, Uganda, since 2003 to date. However, hookworm and schistosomiasis remain prevalent in Mayuge district. Understanding the factors that predispose children to these infections in the context of MDA could inform interventions to reduce prevalence in Uganda and similar settings.

METHOD

This cross-sectional study took place in 33 randomly selected primary schools in the Mayuge district from January to February 2022. Children in primary classes 4 or 5, in the selected schools provided single stool samples and completed questionnaires. Stool specimens were examined using the Kato-Katz method to determine the prevalence of hookworm and schistosomiasis. We performed univariable and multivariable logistic regression to assess the associations of each infection with potential risk factors.

RESULT

A total of 1,617 students (mean age 12.1 years, 50.1% male) were enrolled. The prevalence of hookworm infection and schistosomiasis was 21.8% (95% confidence interval (CI): 19.8-23.9%) and 18.7% (95% CI: 16.8-20.7%), respectively. In multivariable analysis, longer water fetching time (over 30 min versus less than 30 min) and working daily in the soil were associated with increased odds of hookworm infection (adjusted odds ratio (AOR): 1.49, 95% CI: 1.13-1.96 and 1.37, 95% CI: 1.03-1.82, respectively). Higher odds of schistosomiasis were linked to proximity to water bodies within a one-hour walking distance (AOR: 1.84, 95% CI: 1.35-2.50), and not always washing hands before eating (AOR: 2.00, 95% CI: 1.50-2.67). Swimming, bathing, or washing in water bodies twice a week, compared to never, also increased schistosomiasis odds (AOR: 2.91, 95% CI: 1.66-5.13).

CONCLUSION

Consistent with the mechanisms of acquisition, hookworm infection increased with exposure to soil, and schistosomiasis increased with exposure to unclean water. Our findings highlight the importance of Water, Sanitation, and Hygiene programs and strategies aimed at reducing exposure within the framework of Neglected Tropical Disease elimination programs.

Pharmacophore Virtual Screening Identifies Riboflavin as an Inhibitor of the Schistosome Cathepsin B1 Protease with Antiparasitic Activity

Schistosomiasis is a neglected disease of poverty that affects over 200 million people worldwide and relies on a single drug for therapy. The cathepsin B1 cysteine protease (SmCB1) of Schistosoma mansoni has been investigated as a potential target. Here, a structure-based pharmacophore virtual screening (VS) approach was used on a data set of approved drugs to identify potential antischistosomal agents targeting SmCB1. Pharmacophore (PHP) models underwent validation through receiver operating characteristics curves achieving values >0.8. The data highlighted riboflavin (RBF) as a compound of particular interest. A 1 μs molecular dynamics simulation demonstrated that RBF altered the conformation of SmCB1, causing the protease's binding site to close around RBF while maintaining the protease's overall integrity. RBF inhibited the activity of SmCB1 at low micromolar values and killed the parasite in vitro. Finally, in a murine model of S. mansoni infection, oral administration of 100 mg/kg RBF for 7 days significantly decreased worm burdens by ∼20% and had a major impact on intestinal and fecal egg burdens, which were decreased by ∼80%.

Synthesis and anthelmintic activity of novel thiosemicarbazide and 1,2,4-triazole derivatives: In vitro, in vivo, and in silico study

INTRODUCTION

Intestinal parasitic infections are neglected diseases and, due to the increasing resistance of parasites to available drugs, they pose an increasing therapeutic challenge. Therefore, there is a great need for finding new compounds with antiparasitic activity.

OBJECTIVES

In this work, new thiosemicarbazide and 1,2,4-triazole derivatives were synthesized and tested for their anthelmintic activity.

METHODS

The synthesis was carried out by classical methods of organic chemistry. Anthelmintic activity tests were carried out in vitro (Rhabditis sp., Haemonchus contortus, Strongylidae sp.) in vivo (Heligmosomoides polygyrus/bakeri), and in silico analysis was performed.

RESULTS

Quinoline-6-carboxylic acid derivative compounds were designed and synthesized. The highest activity in the screening tests in the Rhabditis model was demonstrated by compound II-1 with a methoxyphenyl substituent LC50 = 0.3 mg/mL. In the next stage of the research, compound II-1 was analyzed in the H. contortus model. The results showed that compound II-1 was active and had ovicidal (percentage of dead eggs > 45 %) and larvicidal (percentage of dead larvae > 75 %) properties. Studies in the Strongylidae sp. model confirmed the ovicidal activity of compound II-1 (percentage of dead eggs ≥ 55 %). In vivo studies conducted in the H. polygyrus/bakeri nematode model showed that the number of nematodes decreased by an average of 30 % under the influence of compound II-1. In silico studies have shown two possible modes of action of compound II-1, i.e. inhibition of tubulin polymerization and SDH. The test compound did not show any systemic toxic effects. Its influence on drug metabolism related to the activity of cytochrome CYP450 enzymes was also investigated.

CONCLUSION

The results obtained in the in vitro, in vivo, and in silico studies indicate that the test compound can be described as a HIT, which in the future may be used in the treatment of parasitic diseases in humans and animals.

Quantifying the neglected: Initial estimation of the global burden and economic impact of human toxocariasis

Toxocariasis is a parasitic zoonotic infection caused by Toxocara spp., ascarid nematodes of companion animals (dogs and cats) affecting people in both high-income and low/middle-income countries. Toxocariasis can manifest as several distinct syndromes. The most frequent, often termed common toxocariasis, is a self-limiting and mild febrile illness. Ocular and visceral larva migrans are severe disease manifestations affecting the eye and other internal organs, respectively, but their reported occurrence is rare. The vast majority of symptomatic cases are thought due to common toxocariasis, which has also been associated with cognitive impairment in children. Few studies to date have sought to quantity the health burden of toxocariasis in humans. In this study we provide a preliminary estimation using the Disability-Adjusted Life Year (DALY) approach. We estimate a total of 23,084 DALYs are lost annually in 28 selected countries due to common toxocariasis. Extrapolating based on a global average seroprevalence rate of 19%, we estimate 91,714 DALYs per year are lost across all countries due to toxocariasis, of which 40,912 are attributable to less severe forms, i.e. common toxocariasis, and 50,731 to cognitive impairment in children. Clinically diagnosed and reported ocular and visceral larva migrans represent a small proportion of estimated total health burden. We also found a positive correlation at national level between prevalence in cats or dogs and seroprevalence in humans, but no correlation between estimated soil contamination and seroprevalence in humans. Finally, we estimate the potential economic impact of toxocariasis in selected countries at 2.5 billion USD per annum, from costs of medical treatment and lost income. These preliminary estimates should serve as a call to action for further research and evidence-based measures to tackle toxocariasis.

Diagnosis of fasciolosis antibodies in Brazilian cattle through ELISA employing both native and recombinant antigens

Bovine fasciolosis is a parasitic disease with a global reach. Coprological based on egg detection in fecal samples and liver inspection to evaluate the presence of the parasite is currently the gold standard for diagnosing chronic fasciolosis in cattle. However, these techniques are labor-intensive and ineffective during the acute phase of the disease. Serodiagnosis using native and recombinant antigens has become an interesting alternative in efforts to identify cattle fasciolosis. We evaluated cattle from abattoir (n = 139) and farms (n = 500) through liver inspection and coprological examination, respectively. Our laboratory team optimized and validated enzyme-linked immunosorbent assay tests based on somatic antigen, excretory/secretory proteins, and the recombinant antigen cathepsin L-1 to detect serum antibodies against fasciolosis in cattle. For animals from abattoir, 10 were positive for fasciolosis according to liver inspection. Both FhES and FhrCL-1 presented an area under the receiver operating characteristic (AUROC) curve of 0.80, with a sensitivity of 0.80 (95% CI: 0.46-0.95) and 0.70 (95% CI: 0.38-0.90) and specificity of 0.81 (95% CI: 0.73-0.87) and 0.87 (95% CI: 0.80-0.92), respectively. For those cattle from farms, 28 were positive only for fasciolosis according to coprological examination. In this scenario, FhES gave the best performance, with an AUROC of 0.84, sensitivity of 0.79 (95% CI: 0.60-0.90), and specificity of 0.86 (95% CI: 0.82-0.89). In conclusion, our study highlights the potential of serodiagnosis for accurately screening cattle fasciolosis. The promising sensitivity and specificity values of FhES when compared to liver inspection or coprological examination enhance its importance for cattle fasciolosis diagnosis.

IMPORTANCE

The aim of this article was to identify antibodies against fasciolosis in cattle in Brazil. The methodology was reproduced in our laboratory and applied for the first time to the Brazilian cattle herd. The antigens tested can be used as a screening test and thus speed up the diagnosis of bovine fascioliasis.

A Minimal Kynurenine Pathway Was Preserved for Rhodoquinone but Not for De Novo NAD+ Biosynthesis in Parasitic Worms: The Essential Role of NAD+ Rescue Pathways

Aims: To determine the role of the kynurenine (KYN) pathway in rhodoquinone (RQ) and de novo NAD+ biosynthesis and whether NAD+ rescue pathways are essential in parasitic worms (helminths). Results: We demonstrate that RQ, the key electron transporter used by helminths under hypoxia, derives from the tryptophan (Trp) catabolism even in the presence of a minimal KYN pathway. We show that of the KYN pathway genes only the kynureninase and tryptophan/indoleamine dioxygenases are essential for RQ biosynthesis. Metabolic labeling with Trp revealed that the lack of the formamidase and kynurenine monooxygenase genes did not preclude RQ biosynthesis in the flatworm Mesocestoides corti. In contrast, a minimal KYN pathway prevented de novo NAD+ biosynthesis, as revealed by metabolic labeling in M. corti, which also lacks the 3-hydroxyanthranilate 3,4-dioxygenase gene. Our results indicate that most helminths depend solely on NAD+ rescue pathways, and some lineages rely exclusively on the nicotinamide salvage pathway. Importantly, the inhibition of the NAD+ recycling enzyme nicotinamide phosphoribosyltransferase with FK866 led cultured M. corti to death. Innovation: We use comparative genomics of more than 100 hundred helminth genomes, metabolic labeling, HPLC-mass spectrometry targeted metabolomics, and enzyme inhibitors to define pathways that lead to RQ and NAD+ biosynthesis in helminths. We identified the essential enzymes of these pathways in helminth lineages, revealing new potential pharmacological targets for helminthiasis. Conclusion: Our results demonstrate that a minimal KYN pathway was evolutionary maintained for RQ and not for de novo NAD+ biosynthesis in helminths and shed light on the essentiality of NAD+ rescue pathways in helminths.

Molecular detection of intestinal parasites in a rural community of Colombia: A one health approach to explore potential environmental-zoonotic transmission

AIMS

Protozoan and helminth parasitic infections pose significant public health challenges, especially in developing countries with rural populations marked by suboptimal hygiene practices and socio-economic constraints. The parasites are the etiological agents of these infections and have a notably elevated global prevalence. Therefore, this study focuses on estimating the frequency and transmission dynamics of several parasitic species, including Blastocystis, Giardia, Cryptosporidium spp., Entamoeba histolytica, Ascaris lumbricoides, Trichuris trichiura, Taenia spp. and hookworms, within a rural community in southwest Colombia with a particular emphasis on the One Health framework, considering environmental and zoonotic transmission potentials.

METHODS AND RESULTS

This study involved the analysis of 125 samples, encompassing human participants (n = 99), their domestic pets (dogs) (n = 24) and water sources (n = 2). Parasite detection was carried out utilizing a combination of microscopy and molecular techniques. Furthermore, the characterization of Blastocystis subtypes (STs) was achieved through Oxford Nanopore sequencing of the rRNA-18S gene. The investigation also entailed the examination of potential associations between intestinal parasitism and various sociodemographic factors. Results revealed a high frequency of parasitic infections when employing molecular methods, with Blastocystis (n = 109/87%), Giardia (n = 20/16%), Ancylostoma duodenale (n = 28/22%), Ancylostoma ceylanicum (n = 7/5.6%), E. histolytica (n = 6/4.8%), Cryptosporidium spp. (n = 12/9.6%) and even Taenia (n = 1/0.8%) detected. Cryptosporidium spp. was also identified in water samples. Coinfections were prevalent, with 57% (n = 70) of samples exhibiting single-parasite infections and 43% (n = 53) showing various degrees of polyparasitism, emphasizing the complexity of transmission dynamics. Blastocystis subtyping, conducted via Oxford Nanopore sequencing, revealed a diversity of subtypes and coexistence patterns, with ST2 being the most prevalent.

CONCLUSIONS

This research underscores the importance of using molecular techniques for frequency estimation, particularly emphasizing the relevance of zoonotic transmission in parasitic infections. It highlights the significance of the One Health approach in comprehending the circulation of parasites among animals, humans and environmental sources, thereby directly impacting public health and epidemiological surveillance.

Efficacy of 400 mg albendazole against soil-transmitted helminthes among Salgy Primary School Children, Dembia district, Northwest Ethiopia, 2020. "Uncontrolled experimental study"

Background and Aims

Soil-transmitted helminths are one of the most prevalent causes of both intellectual and physical disability in the world. Albendazole (ALB) is a drug recommended for mass treatment of the high burden of soil-transmitted helminths in schoolchildren, particularly in developing countries. However, some researchers have reported that the efficacy of albedazole against soil-transmitted helminths is inconsistent. Monitoring the programs is crucial to evaluating the effectiveness of 400 mg of ALB against soil-transmitted helminths, as well as any changes in its therapeutic efficacy. Thus, the purpose of this study was to evaluate ALB effectiveness in treating soil-transmitted helminthes in Salgy Primary School Children.

Methods

An uncontrolled experimental study was conducted at Salgy Primary School Children, Northwest Ethiopia, from March to May 2020. A total of 439 schoolchildren were enrolled and screened for soil-transmitted helminths by stratified proportionate systematic random sampling to get 228 positive schoolchildren. Students in grades one through eight were grouped based on their educational attainment. Using the Kato-Katz thick smear technique, the selected stool sample collected from school children was examined using the Kato-Katz thick smear technique to determine the cure and egg reduction rates. The statistical package for social science software, version 20, was used to analyze the data. To determine the relationship between CR (cure rate) and ERR (egg reduction rate) by age, a chi-square test (X 2) was employed and significance was considered at A 95% confidence interval and p Value (p < 0.05).

Results

A 400 mg single dosage of ALB showed a 99.35% CR and a 97.30% egg reduction rate against Ascaris lumibricoides. Additionally, a 400 mg dose of ALB showed a 95.75% CR and an 82.07% egg reduction rate, suggesting questionable effectiveness against hookworm infections. Trichuris trichiura showed a decreased efficacy, with a 43.53% CR and a 23.12% egg reduction rate.

Conclusion

A single dose of 400 mg ALB is effective (satisfactory), doubtful, and unsatisfactory against Ascaris lumbricoides, hookworm, and T. trichiura infections, respectively. Further studies using different brands, doses, and routes will be needed to treat hookworm and T. trichiura infections successfully by using a larger sample size.

Prevalence and correlates of soil-transmitted helminths in schoolchildren aged 5 to 18 years in low- and middle-income countries: a systematic review and meta-analysis

Background

According to the Global Burden of Disease (GBD) 2019 report, up to 1.5 million disability-adjusted life years (DALYs) are lost due to soil-transmitted helminths (STHs), and 5.9 million people are at risk of acquiring STHs. Regions with the highest prevalence of STH infections include Sub-Saharan Africa, China, South America, and Asia. While there are numerous fragmented studies on STH, comprehensive information on the prevalence and geographic distribution of different species, as well as their regional variations in the context of STHs is limited. The present systematic review and meta-analysis study attempts to provide a summary of the prevalence, geographical variation, and determinants of STHs among schoolchildren aged 5 to 18 years.

Methods

An extensive literature search was carried out using PubMed, Embase, Cinhal, and Psychinfo for studies published between 1999 and 2022 that reported the rate of STH infection in school-going children aged 5-18 years. A random effects model was employed in this meta-analysis due to expected heterogeneity. Subgroup analysis was carried out based on sex and STH species because of expected geographical variation.

Results

A total of 19,725 of the 49,630 children examined were infected with STH, yielding an overall pooled prevalence of 37.16% (95% CI: 29.74-44.89). The prevalence was highest in the Western Pacific region at 50.41% (95% CI: 33.74-67.04) followed by Europe at 39.74% (95% CI: 20.40-61.0) and Africa at 37.10% (95% CI: 26.84-47.95). Ascaris lumbricoides was found to be the most prevalent helminth with a prevalence of 24.07% (95% CI: 17.07-31.83).

Conclusion

The Western Pacific region is classified as a High-risk Zone (HRZ), while Southeast Asia, Africa, Europe, and the Eastern Mediterranean are classified as moderate-risk zones (MRZs). We found a 12% reduction in the pooled prevalence of STH infection from 1999 to 2012. Ascaris lumbricoides was the predominant species among schoolchildren. Mass Drug Administration (MDA) of Albendazole tablets and improved water, sanitation, and hygiene (WASH) practices are effective in controlling and preventing STH. Ensuring their implementation and access is crucial to addressing the problem.

Systematic review registration

https://www.crd.york.ac.uk/prospero/#loginpage, CRD42022333341.

IL-33-binding HpARI family homologues with divergent effects in suppressing or enhancing type 2 immune responses

HpARI is an immunomodulatory protein secreted by the intestinal nematode Heligmosomoides polygyrus bakeri, which binds and blocks IL-33. Here, we find that the H. polygyrus bakeri genome contains three HpARI family members and that these have different effects on IL-33-dependent responses in vitro and in vivo, with HpARI1+2 suppressing and HpARI3 amplifying these responses. All HpARIs have sub-nanomolar affinity for mouse IL-33; however, HpARI3 does not block IL-33-ST2 interactions. Instead, HpARI3 stabilizes IL-33, increasing the half-life of the cytokine and amplifying responses to it in vivo. Together, these data show that H. polygyrus bakeri secretes a family of HpARI proteins with both overlapping and distinct functions, comprising a complex immunomodulatory arsenal of host-targeted proteins.

Tropical high altitude and severe asthma in adults: house dust mite sensitization and phenotypic distribution

BACKGROUND

There is a lack of information on house dust mite (HDM) sensitization and phenotype distribution in patients with severe asthma (SA) living permanently at high-altitude (HA) in tropical regions, which may be different.

OBJECTIVE

The aim of this study was to characterize adults with SA in a tropical high altitude city (2,640 m): Bogotá, Colombia.

MATERIAL AND METHODS

This observational cross-sectional study included severe asthmatic outpatients (n = 129) referred to the ASMAIRE program of the Fundación Neumológica Colombiana in Bogotá (2,640 m). Clinical history, spirometry, total IgE, blood eosinophils, and skin prick test (SPT), including HDM allergens, were performed. Phenotype definitions: Allergic/atopic (AA): IgE ≥100 IU/mL and/or at least one positive SPT; eosinophilic (EOS): blood eosinophils ≥300 cells/µL; type 2-high: AA and/or EOS phenotype; type 2-low: non-AA/non-EOS phenotype (IgE <100 IU/mL, negative SPT, and blood eosinophils <300 cells/µL).

RESULTS

A total of 129 adults with SA were included, 79.8% female. Phenotype distribution: AA: 61.2%; EOS: 37.2%; type 2-high: 72.1%; type 2-low: 27.9%. Among AA patients, HDM sensitization was present in 87% and 34.9% were non-eosinophilic. There was a significant overlap between the phenotypes.

CONCLUSIONS

In contrast to non-tropical high-altitude regions, we found a high frequency of HDM sensitization in patients with AA phenotype living in a tropical high-altitude city. We also found a discrete lower frequency of EOS phenotype with no other significant differences in the phenotypic distribution compared to that described at low altitudes. We propose that tropical location may modify the effect of high altitude on HDM concentrations and allergenicity.

Effectiveness of a School Intervention Based on Knowledge, Attitude, and Practice of Soil-Transmitted Helminths

More than 1.5 billion people are infected by soil-transmitted helminths (STHs) worldwide, comprising one of the world's most serious public health problems. School-age children are the most affected as a result of precarious hygienic habits, especially in economically poor areas that lack appropriate sanitation. Therefore, this study aimed to evaluate a didactic method via a health education approach as a complement to the school curriculum of the sixth-grade students of public schools, distributed among six cities in the state of São Paulo, Brazil. For this, a didactic booklet was elaborated with educational explanatory activities about worms, their life cycle, and how to avoid infections. The intervention was measured by the change caused by knowledge, attitude, and practice (KAP), in students before and after using the notebook, through a questionnaire with high validity and internal consistency. Schools were assigned randomly into intervention and control groups, receiving both the didactic material and the questionnaires, versus the questionnaires only, respectively. The results were submitted to an analysis of covariance that revealed a significant difference pre- and postintervention for knowledge (P < 0.001), with greater means (0.54) compared with the control group (0.44); attitude (P < 0.005), with respective means of 0.56 versus 0.48; and practice (P < 0.001), with means of 0.75 versus 0.57. These findings set the didactic material as a potential tool to complement the school curriculum through KAP without disrupting the teaching system, in addition to assisting teachers in health education at schools aiming to prevent children's infections by STHs.

Molecular identification and genetic diversity of zoonotic hookworm infections in domestic dogs from northeastern, Thailand

Hookworm infections remain a significant public health concern in tropical and subtropical regions, including Thailand. This study investigated the species and genetic diversity of hookworm infections in domestic dogs from northeastern Thailand. The molecular analysis focused on amplifying and sequencing specific regions of ribosomal RNA genes (ITS1-5.8S-ITS2 region) and the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene in hookworm larvae recovered from 21 domestic dog stool samples. Among 21 larvae (one larva per infected dog) analyzed, 14 had sequences identical to Ancylostoma caninum, and 7 showed sequences almost identical to Ancylostoma ceylanicum. Phylogenetic analysis of cox1 sequences placed A. caninum and A. ceylanicum in separate clades. The median-joining network of A. caninum cox1 sequences from Thailand showed high haplotype diversity and belonged to the same cluster as sequences from Australia while forming separate clusters from those of A. caninum samples from the USA. The available published A. ceylanicum cox1 sequences (n = 33), in combination with seven sequences in the present study, represented 15 haplotypes distributed among three clusters. Interestingly, A. ceylanicum sequences from dogs and humans shared the same haplotypes. These findings are crucial for recognizing the potential for zoonotic transmission, highlighting the necessity for targeted control measures, and increasing awareness among pet owners and healthcare professionals to mitigate the risk of hookworm transmission to humans.

Strongyloides ratti infection in mice: immune response and immune modulation

Strongyloides ratti is a natural parasite of wild rats and most laboratory mouse strains are also fully permissive. The infection can be divided into three distinct phases: the tissue migration of the infective third stage larvae during the first two days, the early intestinal establishment of S. ratti parasites molting to adults on days three to six and the later intestinal parasitic phase until the end of infection. Immunocompetent mice terminate the S. ratti infection after one month and are semi-resistant to a second infection. Employing the powerful tools of mouse immunology has facilitated a detailed analysis of the initiation, execution and regulation of the immune response to S. ratti. Here we review the information collected to date on the protective immune response to migrating S. ratti larvae in tissues and to adult parasites in the intestine. We show that depending on the phase of infection, a site-specific portfolio of immune effector mechanisms is required for infection control. In addition, we summarize the strategies employed by S. ratti to evade the immune system and survive long enough in its host to replicate despite an effective immune response. Selected murine studies using the closely related Strongyloides venezuelensis will be discussed. This article is part of the Theo Murphy meeting issue 'Strongyloides: omics to worm-free populations'.

A standard workflow for community-driven manual curation of Strongyloides genome annotations

Advances in the functional genomics and bioinformatics toolkits for Strongyloides species have positioned these species as genetically tractable model systems for gastrointestinal parasitic nematodes. As community interest in mechanistic studies of Strongyloides species continues to grow, publicly accessible reference genomes and associated genome annotations are critical resources for researchers. Genome annotations for multiple Strongyloides species are broadly available via the WormBase and WormBase ParaSite online repositories. However, a recent phylogenetic analysis of the receptor-type guanylate cyclase (rGC) gene family in two Strongyloides species highlights the potential for errors in a large percentage of current Strongyloides gene models. Here, we present three examples of gene annotation updates within the Strongyloides rGC gene family; each example illustrates a type of error that may occur frequently within the annotation data for Strongyloides genomes. We also extend our analysis to 405 previously curated Strongyloides genes to confirm that gene model errors are found at high rates across gene families. Finally, we introduce a standard manual curation workflow for assessing gene annotation quality and generating corrections, and we discuss how it may be used to facilitate community-driven curation of parasitic nematode biodata. This article is part of the Theo Murphy meeting issue 'Strongyloides: omics to worm-free populations'.

Intestinal parasitic infections and risk analysis among urban refugees in the Klang Valley, Malaysia

BACKGROUND

Global studies show intestinal parasitic infections (IPIs) have been introduced and spread with refugee inflows from low to high socio-economic countries. However, there is relatively limited information on the prevalence of infections among the community.

METHODS

A 2-year cross-sectional study was conducted to determine the prevalence and associated risk factors for infections among urban refugees in the Klang Valley, Malaysia. A total of 418 faecal samples were collected and examined by microscopy.

RESULTS

Faecal screening revealed moderate levels (32.3%) of infections in the community. Three nematode (Ascaris lumbricoides, Trichuris trichiura and hookworm) and three protozoan species (Entamoeba, Giardia and Cryptosporidium) were recorded, with the highest prevalence being A. lumbricoides (20.6%) followed by T. trichiura (10.3%), while other infections were <5%. Statistical analysis found that young males with less education were more likely to be infected with helminths. Additionally, living near waste disposal sites, the presence of stray animals, eating with bare hands, bare footedness, poor handwashing practices and no anthelmintic treatment constituted significant risk factors for helminth infections. Protozoan infections were linked to drinking tap water or from water dispensers and poor handwashing practices.

CONCLUSIONS

These findings emphasize the importance of health education in addition to introduction of biannual anthelmintic treatment to promote community health and well-being.

Unlocking the Pharmacological Potential of Benzimidazole Derivatives: A Pathway to Drug Development

Heterocyclic molecules have fascinated a massive interest in medicinal chemistry. They are heterocyclic compounds that have gained significance due to their diverse variety of pharmacological activities. Benzimidazole is a heterocyclic compound consisting of benzene and imidazole rings. The ease of synthesis and the structural versatility of benzimidazole make it a promising scaffold for drug development. Many biological actions of benzimidazole derivatives have been well documented, including antibacterial, antiviral, anticancer, anti-inflammatory, antitubercular, and anthelmintic properties. The mechanism of action of benzimidazole derivatives varies with their chemical structure and target enzyme. This review has explored numerous methods for producing benzimidazole derivatives as well as a broad range of pharmacological activities. SAR investigations are also discussed in this review as they provide crucial details regarding the essential structural qualities that benzimidazole derivatives must have in order to be biologically active, which could aid in the rational design of new drug candidates. Benzimidazole scaffold is an exclusive structure in drug design and discovery. Many new pharmaceutical drugs containing benzimidazole are anticipated to be available within the next ten years as a result of the extensive therapeutic applications of benzimidazole and its derivatives. This review inspired many researchers to develop more biologically active compounds bearing benzimidazole, expanding the scope of finding a remedy for other diseases. From this study, we concluded that 2-substituted benzimidazole was considered more extensively by researchers.

Nanomaterials as a Potential Target for Infectious Parasitic Agents

Despite the technological advancement in the era of personalized medicine and therapeutics development, infectious parasitic causative agents remain one of the most challenging areas of research and development. The disadvantages of conventional parasitic prevention and control are the emergence of multiple drug resistance as well as the non-specific targeting of intracellular parasites, which results in high dose concentration needs and subsequently intolerable cytotoxicity. Nanotechnology has attracted extensive interest to reduce medication therapy adverse effects including poor bioavailability and drug selectivity. Numerous nanomaterials-based delivery systems have previously been shown in animal models to be effective in the treatment of various parasitic infections. This review discusses a variety of nanomaterials-based antiparasitic procedures and techniques as well as the processes that allow them to be targeted to different parasitic infections. This review focuses on the key prerequisites for creating novel nanotechnology-based carriers as a potential option in parasite management, specifically in the context of human-related pathogenic parasitic agents.

The Roles of Various Immune Cell Populations in Immune Response against Helminths

Helminths are multicellular parasites that are a substantial problem for both human and veterinary medicine. According to estimates, 1.5 billion people suffer from their infection, resulting in decreased life quality and burdens for healthcare systems. On the other hand, these infections may alleviate autoimmune diseases and allergy symptoms. The immune system is programmed to combat infections; nevertheless, its effector mechanisms may result in immunopathologies and exacerbate clinical symptoms. This review summarizes the role of the immune response against worms, with an emphasis on the Th2 response, which is a hallmark of helminth infections. We characterize non-immune cells (enteric tuft cells-ETCs) responsible for detecting parasites, as well as the role of hematopoietic-derived cells (macrophages, basophils, eosinophils, neutrophils, innate lymphoid cells group 2-ILC2s, mast cells, T cells, and B cells) in initiating and sustaining the immune response, as well as the functions they play in granulomas. The aim of this paper is to review the existing knowledge regarding the immune response against helminths, to attempt to decipher the interactions between cells engaged in the response, and to indicate the gaps in the current knowledge.

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.

The immunomodulatory effects of the C-type lectin protein of Toxocara canis on experimental autoimmune encephalomyelitis

Toxocara canis is a global zoonosis infection that can cause chronic and long-term toxocariasis in their paratenic host. The excretory-secretory (ES) products of T. canis larvae are considered to be responsible for the Th2 polarization and regulatory immune responses in toxocariasis. The C-type lectin family is one of the most prominent components of ES products of T. canis infective larvae. This study aimed to investigate the ameliorative effect of a T. canis C-type lectin recombinant protein (rCTL), on experimental autoimmune encephalomyelitis (EAE) which is a T-cell-mediated autoimmune disease of the central nervous system. C57BL/6 mice were subcutaneously treated with 30 μg rCTL, three times at an interval of 1 week. EAE was induced by myelin oligodendrocyte glycoprotein 35-55 peptide (MOG35-55 peptide) immunization, and weight and clinical scores were evaluated. Real time polymerase chain reaction was performed to evaluate the expression levels of T-bet, Gata3, and Foxp3 in splenocytes. In addition, the levels of interleukin 4, interferon gamma, and tumour growth factor-β (TGF-β) were quantified by enzyme-linked immunosorbent assay in splenocyte culture supernatants. The results indicated that the rCTL decreased clinical disability scores and delayed the onset of EAE. Furthermore, the data showed that rCTL treatment modulated the immune response, which was associated with upregulation of the mRNA expression of the Foxp3 gene and higher production of TGF-β in rCTL-treated mice. This study demonstrated that rCTL might be a potential agent to ameliorate EAE symptoms by stimulating anti-inflammatory responses.

Mitigating the effects of climate change on human health with vaccines and vaccinations

Climate change represents an unprecedented threat to humanity and will be the ultimate challenge of the 21st century. As a public health consequence, the World Health Organization estimates an additional 250,000 deaths annually by 2030, with resource-poor countries being predominantly affected. Although climate change's direct and indirect consequences on human health are manifold and far from fully explored, a growing body of evidence demonstrates its potential to exacerbate the frequency and spread of transmissible infectious diseases. Effective, high-impact mitigation measures are critical in combating this global crisis. While vaccines and vaccination are among the most cost-effective public health interventions, they have yet to be established as a major strategy in climate change-related health effect mitigation. In this narrative review, we synthesize the available evidence on the effect of climate change on vaccine-preventable diseases. This review examines the direct effect of climate change on water-related diseases such as cholera and other enteropathogens, helminthic infections and leptospirosis. It also explores the effects of rising temperatures on vector-borne diseases like dengue, chikungunya, and malaria, as well as the impact of temperature and humidity on airborne diseases like influenza and respiratory syncytial virus infection. Recent advances in global vaccine development facilitate the use of vaccines and vaccination as a mitigation strategy in the agenda against climate change consequences. A focused evaluation of vaccine research and development, funding, and distribution related to climate change is required.

How important is the spatial movement of people in attempts to eliminate the transmission of human helminth infections by mass drug administration?

Human mobility contributes to the spatial dynamics of many infectious diseases, and understanding these dynamics helps us to determine the most effective ways to intervene and plan surveillance. In this paper, we describe a novel transmission model for the spatial dynamics of hookworm, a parasitic worm which is a common infection across sub-Saharan Africa, East Asia and the Pacific islands. We fit our model, with and without mobility, to data obtained from a sub-county in Kenya, and validate the model's predictions against the decline in prevalence observed over the course of a clustered randomized control trial evaluating methods of administering mass chemotherapy. We find that our model which incorporates human mobility is able to reproduce the observed patterns in decline of prevalence during the TUMIKIA trial, and additionally, that the widespread bounce-back of infection may be possible over many years, depending on the rates of people movement between villages. The results have important implications for the design of mass chemotherapy programmes for the elimination of human helminth transmission. This article is part of the theme issue 'Challenges and opportunities in the fight against neglected tropical diseases: a decade from the London Declaration on NTDs'.

Efficacy of smallpox vaccines against Mpox infections in humans

The Mpox virus (MPXV) is endemic in certain countries in Central and West Africa, where several mammalian species, especially rodents, are natural reservoirs. However, the MPXV can infect nonhuman primates and cause zoonotic infections in humans after close contact with an infected animal. Human-to-human transmission of MPXV can also occur through direct close contact with an infected individual or infected materials. In May 2022 an initial cluster of human Mpox cases was identified in the UK, with the first case confirmed in a patient who had recently travelled to Nigeria. The infection subsequently spread via human-to-human transmission within the UK and Mpox cases began to appear in many other countries around the world where the MPXV is not endemic. No specific treatments for MPXV infection in humans are available. However, data from studies undertaken in Zaire in the 1980s revealed that those with a history of smallpox vaccination during the global smallpox eradication campaign also had good cross-protection against MPXV infection. However, the vaccines used during the global eradication campaign are no longer available. During the 2022 global Mpox outbreak over a million doses of the Modified Vaccinia Ankara-Bavarian Nordic (MVA-BN) smallpox vaccine were offered either as pre or postexposure prophylaxis to those at high risk of MPXV infection. Here, we review what has been learned about the efficacy of smallpox vaccines in reducing the incidence of MPXV infections in high-risk close contacts.

The impact of helminth-induced immunity on infection with bacteria or viruses

Different human and animal pathogens trigger distinct immune responses in their hosts. The infection of bacteria or viruses can trigger type I pro-inflammatory immune responses (e.g., IFN-γ, TNF-α, TH1 cells), whereas infection by helminths typically elicits a type II host resistance and tolerizing immune response (e.g., IL-4, IL-5, IL-13, TH2 cells). In some respects, the type I and II immune responses induced by these different classes of pathogens are antagonistic. Indeed, recent studies indicate that infection by helminths differentially shapes the response and outcome of subsequent infection by viruses and bacteria. In this review, we summarize the current knowledge on how helminth infections influence concurrent or subsequent microbial infections and also discuss the implications for helminth-mediated immunity on the outcome of SARS-CoV-2 disease.

Guidelines for the purification and characterization of extracellular vesicles of parasites

Parasites are responsible for the most neglected tropical diseases, affecting over a billion people worldwide (WHO, 2015) and accounting for billions of cases a year and responsible for several millions of deaths. Research on extracellular vesicles (EVs) has increased in recent years and demonstrated that EVs shed by pathogenic parasites interact with host cells playing an important role in the parasite's survival, such as facilitation of infection, immunomodulation, parasite adaptation to the host environment and the transfer of drug resistance factors. Thus, EVs released by parasites mediate parasite-parasite and parasite-host intercellular communication. In addition, they are being explored as biomarkers of asymptomatic infections and disease prognosis after drug treatment. However, most current protocols used for the isolation, size determination, quantification and characterization of molecular cargo of EVs lack greater rigor, standardization, and adequate quality controls to certify the enrichment or purity of the ensuing bioproducts. We are now initiating major guidelines based on the evolution of collective knowledge in recent years. The main points covered in this position paper are methods for the isolation and molecular characterization of EVs obtained from parasite-infected cell cultures, experimental animals, and patients. The guideline also includes a discussion of suggested protocols and functional assays in host cells.

Anthelmintic efficacy of Holarrhena pubescens against Raillietina spp. of domestic fowl through ultrastructural, histochemical, biochemical and GLCM analysis

Globally, traditional knowledge systems are a powerhouse of information which can revolutionise the world, if decoded accurately and logically. Plant-based ethno-traditional and folklore curatives/medicines has a firm basis in the psyche of the common masses of West Bengal and Holarrhena pubescens is a representative example of it. This article communication on depicting the anthelmintic efficacy of ethanolic extract and Ethyl acetate fraction of the stem bark of Holarrhena pubescens against the cestode Raillietina spp. through efficacy studies, ultra-structural observations, histochemical and biochemical analysis on some tegumental enzymes i.e., Acid Phosphatase (AcPase), Alkaline Phosphatase (AlkPase), Adenosine Triphosphatase (ATPase) and 5'-Nucleotidase (5'-Nu) along with Gray Level Co-occurrence Matrix (GLCM) analysis of histochemical study. Praziquantel was used as the reference drug. Investigations revealed 10mg/ml dosage of crude extract was the most efficacious dose and amongst the fractions the ethyl acetate fraction showed the most anthelmintic property. Ultrastructural studies through Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) clearly depicted the damage in head, sucker, proglottids, proximal and distal cytoplasm (DC), microtriches (MT), basal lamina (BL), nuclear membrane (NM), and, nucleolus (NL) in the treated worms. Histochemical studies revealed decrease in staining intensity for all the tegumental enzymes in the treated worms compared to control. The GLCM analysis strongly supported the result of histochemical studies. Biochemical studies revealed marked reduction in enzyme activity in the treated worms with maximum reduction in the activity of 5'- Nu (77.8%) followed by ATPase (63.17%).

Progress from morbidity control to elimination as a public health problem of schistosomiasis and the status of soil-transmitted helminth infection in Togo: a second impact assessment after ten rounds of mass drug administration

BACKGROUND

Due to the burden of schistosomiasis (SCH) and soil-transmitted helminths (STH), Togo Ministry of Health launched a program for Preventive Chemotherapy Neglected Tropical Diseases (PC-NTDs) in 2009, initiating integrated mass drug administration (MDA) the following year for the three PC-NTDs: SCH, STH and onchocerciasis. Significant reduction of infection across the country was noted in 2015 during the first impact assessment, following 5 years of high-coverage MDA implemented at the sub-district level for SCH and district level for STH. After another 5 years of effective MDA, a second survey was conducted in 2021 to re-evaluate the situation of SCH and STH.

METHODS

A cross-section of school-aged children was taken across ten districts of Togo. A total of 302 schools in 92 sub-districts were sampled, with 24 school-aged children per school resulting in 7248 children surveyed. Urine samples were tested by haemastix® for Schistosoma haematobium, with urine filtration for the presence of eggs conducted on haematuria-positive samples. Stool samples were collected in a subset of 34 sub-districts in seven out of the ten surveyed districts, where STH and Schistosoma mansoni endemicity was high during the 2015 impact assessment. Duplicate (two) Kato-Katz analysis was performed for each stool sample. Sociodemographic and school-level water, sanitation and hygiene information was also collected.

RESULTS

Overall, SCH prevalence was 5.90% (95% CI: 5.4-6.5), with 5.09% (95% CI: 4.64-5.67) for S. haematobium and 2.56% (95% CI: 1.98-3.29) for S. mansoni. STH prevalence was 19.7% (95% CI: 18.2-21.4), with 19.6% (95% CI: 18.1-21.3) hookworm, 0.08% (95% CI: 2.2-5.8) Trichuris trichiura and 0.04% (95% CI: 0.01-0.33) Ascaris lumbricoides. Compared to baseline, a significant reduction in both SCH (22.2% to 5.90%) and STH (29.2% t0 19.7%) prevalence was observed. Children aged 5-9 years were less infected than older peers aged 10-14 years: 4.76% vs. 7.53% (P < 0.01) for SCH and 17.2% vs. 23.0% (P < 0.01) for STH.

CONCLUSIONS

After 10 years of high coverage integrated MDA, Togo has achieved low prevalence SCH infection through the sub-district MDA implementation with considerable infection heterogeneity within sub-districts. As STH infection has not reached a level where the infections are not a public health problem, the sub-district treatment strategy could also be adopted in addition to improvement of treatment coverage among preschool age children and hygiene and sanitation practices.

Discovery of long non-coding RNAs in the liver fluke, Fasciola hepatica

Long non-coding (lnc)RNAs are a class of eukaryotic RNA that do not code for protein and are linked with transcriptional regulation, amongst a myriad of other functions. Using a custom in silico pipeline we have identified 6,436 putative lncRNA transcripts in the liver fluke parasite, Fasciola hepatica, none of which are conserved with those previously described from Schistosoma mansoni. F. hepatica lncRNAs were distinct from F. hepatica mRNAs in transcript length, coding probability, exon/intron composition, expression patterns, and genome distribution. RNA-Seq and digital droplet PCR measurements demonstrated developmentally regulated expression of lncRNAs between intra-mammalian life stages; a similar proportion of lncRNAs (14.2%) and mRNAs (12.8%) were differentially expressed (p<0.001), supporting a functional role for lncRNAs in F. hepatica life stages. While most lncRNAs (81%) were intergenic, we identified some that overlapped protein coding loci in antisense (13%) or intronic (6%) configurations. We found no unequivocal evidence for correlated developmental expression within positionally correlated lncRNA:mRNA pairs, but global co-expression analysis identified five lncRNA that were inversely co-regulated with 89 mRNAs, including a large number of functionally essential proteases. The presence of micro (mi)RNA binding sites in 3135 lncRNAs indicates the potential for miRNA-based post-transcriptional regulation of lncRNA, and/or their function as competing endogenous (ce)RNAs. The same annotation pipeline identified 24,141 putative lncRNAs in F. gigantica. This first description of lncRNAs in F. hepatica provides an avenue to future functional and comparative genomics studies that will provide a new perspective on a poorly understood aspect of parasite biology.

Exposure to lung-migrating helminth protects against murine SARS-CoV-2 infection through macrophage-dependent T cell activation

Helminth endemic regions report lower COVID-19 morbidity and mortality. Here, we show that lung remodeling from a prior infection with a lung-migrating helminth, Nippostrongylus brasiliensis, enhances viral clearance and survival of human-ACE2 transgenic mice challenged with SARS-CoV-2 (SCV2). This protection is associated with a lymphocytic infiltrate, including increased accumulation of pulmonary SCV2-specific CD8+ T cells, and anti-CD8 antibody depletion abrogated the N. brasiliensis-mediated reduction in viral loads. Pulmonary macrophages with a type 2 transcriptional and epigenetic signature persist in the lungs of N. brasiliensis-exposed mice after clearance of the parasite and establish a primed environment for increased CD8+ T cell recruitment and activation. Accordingly, depletion of macrophages ablated the augmented viral clearance and accumulation of CD8+ T cells driven by prior N. brasiliensis infection. Together, these findings support the concept that lung-migrating helminths can limit disease severity during SCV2 infection through macrophage-dependent enhancement of antiviral CD8+ T cell responses.

M1/M2 macrophages and their overlaps - myth or reality?

Macrophages represent heterogeneous cell population with important roles in defence mechanisms and in homoeostasis. Tissue macrophages from diverse anatomical locations adopt distinct activation states. M1 and M2 macrophages are two polarized forms of mononuclear phagocyte in vitro differentiation with distinct phenotypic patterns and functional properties, but in vivo, there is a wide range of different macrophage phenotypes in between depending on the microenvironment and natural signals they receive. In human infections, pathogens use different strategies to combat macrophages and these strategies include shaping the macrophage polarization towards one or another phenotype. Macrophages infiltrating the tumours can affect the patient's prognosis. M2 macrophages have been shown to promote tumour growth, while M1 macrophages provide both tumour-promoting and anti-tumour properties. In autoimmune diseases, both prolonged M1 activation, as well as altered M2 function can contribute to their onset and activity. In human atherosclerotic lesions, macrophages expressing both M1 and M2 profiles have been detected as one of the potential factors affecting occurrence of cardiovascular diseases. In allergic inflammation, T2 cytokines drive macrophage polarization towards M2 profiles, which promote airway inflammation and remodelling. M1 macrophages in transplantations seem to contribute to acute rejection, while M2 macrophages promote the fibrosis of the graft. The view of pro-inflammatory M1 macrophages and M2 macrophages suppressing inflammation seems to be an oversimplification because these cells exploit very high level of plasticity and represent a large scale of different immunophenotypes with overlapping properties. In this respect, it would be more precise to describe macrophages as M1-like and M2-like.

Oral non-viral gene delivery platforms for therapeutic applications

Since gene therapy can regulate gene and protein expression directly, it has a great potential to prevent or treat a variety of genetic or acquired diseases through vaccines such as viral infections, cystic fibrosis, and cancer. Owing to their high efficacy, in vivo gene therapy trials are usually conducted intravenously, which is usually costly and invasive. There are several advantages to oral drug administration over intravenous injections, such as better patient compliance, ease of use, and lower cost. However, gene therapy is successful if the oligonucleotides can cross the cell membrane easily and reach the nucleus after the endosomal escape. In order to accomplish this task and deliver the cargo to the intended location, appropriate delivery systems should be introduced. This review summarizes oral delivery systems developed for effective gene delivery, vaccination, and treatment of various diseases. Studies have also shown that oral delivery approaches are potentially applicable to treat various diseases, especially inflammatory bowel disease, stomach, and colorectal cancers. Also, the current review provides an update overview on the development of non-viral and oral gene delivery techniques for gene therapy and vaccination purposes.

Targeted insertion and reporter transgene activity at a gene safe harbor of the human blood fluke, Schistosoma mansoni

The identification and characterization of genomic safe harbor sites (GSHs) can facilitate consistent transgene activity with minimal disruption to the host cell genome. We combined computational genome annotation and chromatin structure analysis to predict the location of four GSHs in the human blood fluke, Schistosoma mansoni, a major infectious pathogen of the tropics. A transgene was introduced via CRISPR-Cas-assisted homology-directed repair into one of the GSHs in the egg of the parasite. Gene editing efficiencies of 24% and transgene-encoded fluorescence of 75% of gene-edited schistosome eggs were observed. The approach advances functional genomics for schistosomes by providing a tractable path for generating transgenics using homology-directed, repair-catalyzed transgene insertion. We also suggest that this work will serve as a roadmap for the development of similar approaches in helminths more broadly.

Effect of Deworming on Health Outcomes among Children Aged 12-59 Months in Tanzania: A Multilevel Mixed Effects Analysis

Introduction

Mass deworming of preschool children is a strategy suggested to prevent soil-transmitted helminth infections in most developing countries. Nonetheless, there is a scarcity of data showing the contribution of mass deworming to a child's nutritional status. The purpose of this study was to assess the effect of deworming on nutritional health outcomes (stunting, underweight, and anemia) in children aged 12 to 59 months.

Methods

A secondary analysis of data extracted from the Tanzania Demographic and Health Survey (TDHS) 2015-16 data was carried out. A total of 7,962 children were included in this study. A multilevel logistic regression was used at a 5% level of significance to determine the individual- and community-level determinants of deworming on health outcomes among children.

Results

The prevalence of underweight (62.6%), stunting (61.0%), and anemia (61.8%) was higher in children who were not dewormed than those who were dewormed. Female children were more likely to suffer from poor health outcomes (OR = 1.01 and 95% CI = 0.95-1.07) than male children. Children aged 24-35 months and 36-47 months were significantly less likely to suffer from poor health outcomes (OR = 0.89; 95% CI = 0.82-0.97 and OR = 0.88; 96% CI = 0.81-0.96, respectively; p < 0.01). Children from households with unimproved toilets (OR = 1.38 and 95% CI = 1.25-1.52), unimproved water sources (OR = 1.08 and 95% CI = 1.01-1.16), and living in rural areas (OR = 1.02 and 95% CI = 0.91-1.14) had higher odds for poor health outcomes.

Conclusion

Deworming may be an effective technique for preventing poor health outcomes in children and the risks associated with them, such as poor growth and development.

Intestinal helminthic infections: a narrative review to guide the hepatogastroenterologist

Intestinal helminthic infections are not uncommon in Western Europe, mainly due to modern travel, emigration and globalization. Moreover, some helminthic infections are endemic in Western Europe and are part of the everyday clinical practice. The hepatogastroenterologist should therefore recognize and manage these patients or at least refer them to appropriate reference centers. Signs and symptoms are often unspecific or even absent. Discerning the disease at an early stage avoids expensive diagnostic testing, life-threatening complications and in some cases even further spread of the disease. This review article aims to guide the hepatogastroenterologist when suspecting a helminthic infection by addressing the most prevalent symptoms, summarizing the most probable associated helminthic entities, highlighting practical steps in diagnosis and available treatments.

Epidemiology of soil-transmitted helminths using quantitative PCR and risk factors for hookworm and Necator americanus infection in school children in Dak Lak province, Vietnam

BACKGROUND

Soil-transmitted helminth (STH) infection is driven by a complex interaction of demographic, socioeconomic and behavioural factors, including those related to water, sanitation and hygiene (WASH). Epidemiological studies that measure both infection and potential risk factors associated with infection help to understand the drivers of transmission in a population and therefore can provide information to optimise STH control programmes.

METHODS

During October and November 2019, we conducted a cross-sectional survey of the prevalence and intensity of STH infection and associated risk factors among 7710 primary-school-age children from 64 primary schools across 13 districts in Dak Lak province, Vietnam. Quantitative PCR (qPCR) was used to detect and quantify STH infections.

RESULTS

The predominant STH species was the hookworm Necator americanus (overall cluster-adjusted prevalence of 13.7%), and its prevalence was heterogeneously distributed across surveyed schools (0% to 56.3%). All other STH species had a prevalence of less than 1%. Using mixed-effects logistic regression, we found that the adjusted odds ratio (aOR) was significantly higher for both infection and moderate-to-heavy-intensity infection with N. americanus among children from multiple ethnic minority groups, compared to children from the majority group (Kinh). Adjusted odds of infection with N. americanus were also higher in children who reported practising open defecation at school (aOR 1.42, 95% CI 1.05, 1.93, P = 0.02) and in those who had an unimproved household water supply (aOR 1.28, 95% CI 1.04, 1.57, P = 0.02). Conversely, children with a flushing household toilet had a reduced risk of infection (aOR 0.58, 95% CI 0.47, 0.70, P < 0.01), as did those whose primary female carer attended secondary (aOR 0.65, 95% CI 0.51, 0.84, P < 0.01) or tertiary education (aOR 0.39, 95% CI 0.24, 0.63, P < 0.01).

CONCLUSIONS

This study is the largest reported prevalence survey of STH infections conducted using qPCR as a diagnostic technique. The findings of higher adjusted odds of infection amongst ethnic minority children highlight that STH control programmes may not be reaching certain population groups and that additional culturally appropriate approaches may be required. Additionally, the associations between specific WASH factors and infection indicate potential programmatic targets to complement preventive chemotherapy programmes.

Metabolomics and lipidomics studies of parasitic helminths: molecular diversity and identification levels achieved by using different characterisation tools

INTRODUCTION

Helminths are parasitic worms that infect millions of people worldwide and secrete a variety of excretory-secretory products (ESPs), including proteins, peptides, and small molecules. Despite this, there is currently no comprehensive review article on cataloging small molecules from helminths, particularly focusing on the different classes of metabolites (polar and lipid molecules) identified from the ESP and somatic tissue extracts of helminths that were studied in isolation from their hosts.

OBJECTIVE

This review aims to provide a comprehensive assessment of the metabolomics and lipidomics studies of parasitic helminths using all available analytical platforms.

METHOD

To achieve this objective, we conducted a meta-analysis of the identification and characterization tools, metabolomics approaches, metabolomics standard initiative (MSI) levels, software, and databases commonly applied in helminth metabolomics studies published until November 2021.

RESULT

This review analyzed 29 studies reporting the metabolomic assessment of ESPs and somatic tissue extracts of 17 helminth species grown under ex vivo/in vitro culture conditions. Of these 29 studies, 19 achieved the highest level of metabolite identification (MSI level-1), while the remaining studies reported MSI level-2 identification. Only 155 small molecule metabolites, including polar and lipids, were identified using MSI level-1 characterization protocols from various helminth species. Despite the significant advances made possible by the 'omics' technology, standardized software and helminth-specific metabolomics databases remain significant challenges in this field. Overall, this review highlights the potential for future studies to better understand the diverse range of small molecules that helminths produce and leverage their unique metabolomic features to develop novel treatment options.

Feasibility of Training Community Health Workers to Use Smartphone-Attached Microscopy for Point-of-Care Visualization of Soil-Transmitted Helminths in the Peruvian Amazon

The prevalence of soil-transmitted helminths (STH) is high in communities within the Peruvian Amazon despite repeated mass-drug administration, demanding alternative strategies of control. Smartphone-attached microscopy (SAM) permits visualization of STH from a small portable microscope through a smartphone screen, potentially providing an inexpensive and rapid method of STH visualization in communities where diagnostic laboratories with microscopes are inaccessible. In this study, a total of 45 community health workers who work within the health systems of Loreto, Peru, attended a 1-day training session with lectures and practicums on STH and SAM. Participants received a pre- and post-intervention questionnaire. Post-intervention, participants were significantly more confident using SAM and identifying parasite images, symptoms, transmission, and treatment (P ≤ 0.0045). Post-intervention, participants correctly labeled a median of five of seven SAM apparatus components and five of eight steps of Kato-Katz technique, were less likely to choose taking medicine to prevent parasite infection (P = 0.0075), and were more likely to select Kato-Katz technique as a type of diagnostic test (P < 0.0001). Most participants felt ready to use SAM in their communities and stated that it could help rural communities far from health centers or laboratories (24%); provide faster identification, results, diagnosis (19%); permit at-home or on-the-spot visualization (14%); and save money (14%). Results show that community health workers show a high level of willingness and competency to learn about both STH and SAM and may be a yet-unexplored practical method of augmenting STH visualization, bringing healthcare to communities in Loreto with poor access to diagnostic laboratories and clinics.

Stage-Dependent Increase of Systemic Immune Activation and CCR5+CD4+ T Cells in Filarial Driven Lymphedema in Ghana and Tanzania

Chronic lymphedema caused by infection of Wuchereria bancrofti is a disfiguring disease that leads to physical disability, stigmatization, and reduced quality of life. The edematous changes occur mainly on the lower extremities and can progress over time due to secondary bacterial infections. In this study, we characterized participants with filarial lymphedema from Ghana and Tanzania as having low (stage 1-2), intermediate (stage 3-4), or advanced (stage 5-7) lymphedema to determine CD4⁺ T cell activation patterns and markers associated with immune cell exhaustion. A flow cytometry-based analysis of peripheral whole blood revealed different T cell phenotypes within participants with different stages of filarial lymphedema. In detail, increased frequencies of CD4⁺HLA-DR⁺CD38⁺ T cells were associated with higher stages of filarial lymphedema in patients from Ghana and Tanzania. In addition, significantly increased frequencies of CCR5⁺CD4⁺ T cells were seen in Ghanaian participants with advanced LE stages, which was not observed in the Tanzanian cohort. The frequencies of CD8⁺PD-1⁺ T cells were augmented in individuals with higher stage lymphedema in both countries. These findings show distinct activation and exhaustion patterns in lymphedema patients but reveal that immunological findings differ between West and East African countries.

Blocking BAFF Alleviates Hepatic Fibrosis in Schistosoma japonicum-Infected Mice

Schistosomiasis is an immunopathogenic disease characterized by egg granuloma and fibrosis. The hepatic fibrosis of schistosomiasis is caused by the coordinated action of local immune cells, liver-resident cells and related cytokines around the eggs of the liver. B-cell-activating factor (BAFF), expressed in many cells, is an essential factor for promoting the survival, differentiation, and maturation of cells. The overexpression of BAFF is closely related to many autoimmune diseases and fibrosis, but has not been reported to play a role in liver fibrosis caused by schistosomiasis. In the study, we found that, during Schistosoma japonicum (S. japonicum) infection in mice, the level of BAFF and its receptor BAFF-R progressively increased, then decreased with the extension of infection time, which was consistent with the progression of hepatic granuloma and fibrosis. Anti-BAFF treatment attenuated the histopathological damage in the liver of infected mice. The average areas of individual granulomas and liver fibrosis in anti-BAFF treatment mice were significantly lower than those in control mice, respectively. Anti-BAFF treatment increased the IL-10, decreased IL-4, IL-6, IL-17A, TGF-β, and downregulated the antibody level against S. japonicum antigens. These results suggested that BAFF acts a strong player in the immunopathology of schistosomiasis. Anti-BAFF treatment may influence Th2 and Th17 responses, and reduce the inflammatory reaction and fibrosis of schistosomiasis liver egg granuloma. It is suggested that BAFF might be a prospective target for the development of new methods to treat schistosomiasis liver fibrosis.

Antimicrobial and anthelmintic activities of aryl urea agents

OBJECTIVES

This study aimed to characterise compounds with activity against carbapenemase-expressing Gram-negative bacteria and nematodes and evaluate their cytotoxicity to non-cancerous human cells.

METHODS

The antimicrobial activity and toxicity of a series of phenyl-substituted urea derivatives were evaluated using broth microdilution, chitinase, and resazurin reduction assays.

RESULTS

The effects of different substitutions present on the nitrogen atoms of the urea backbone were investigated. Several compounds were active against Staphylococcus aureus and Escherichia coli control strains. Specifically, derivatives 7b, 11b, and 67d exhibited antimicrobial activity against Klebsiella pneumoniae 16, a carbapenemase-producing Enterobacteriaceae species, with minimum inhibitory concentration (MIC) values of 100, 50, and 72 µM (32, 64, and 32 mg/L), respectively. In addition, the MICs obtained against a multidrug-resistant E. coli strain were 100, 50, and 36 µM (32, 16, and 16 mg/L) for the same compounds, respectively. Furthermore, the urea derivatives 18b, 29b, 50c, 51c, 52c, 55c-59c, and 62c were very active towards the nematode Caenorhabditis elegans.

CONCLUSIONS

Testing on non-cancerous human cell lines suggested that some of the compounds have the potential to affect bacteria, especially helminths, with limited cytotoxicity to humans. Given the simplicity of synthesis for this class of compounds and their potency against Gram-negative, carbapenemase-expressing K. pneumoniae, aryl ureas possessing the 3,5-dichloro-phenyl group certainly warrant further investigation to exploit their selectivity.

Artemisia vulgaris anthelmintic activities to ova and adult stages of Fasciola gigantica in vitro

Background and Aim

Fasciolosis due to Fasciola gigantica is endemic to tropical countries and Fasciola hepatica in temperate climates, highly detrimental to livestock and known as foodborne zoonotic diseases. The strategic control of the disease is mainly the use of chemical anthelmintic. This study aimed to evaluate the anthelmintic properties of Artemisia vulgaris extract on the ova and adult stages of F. gigantica.

Materials and Methods

Samples were collected from the Ampel Abbatoir, Boyolali District, Central Java, Indonesia. The ova from 20-gallbladders of cattle which were naturally infected with F. gigantica and 270 living F. gigantica worms were used in this study. The ovicidal assay was performed by incubating the ova with A. vulgaris in different concentrations, that is, 5%, 2.5%, and 1.25% for 5, 9, 11, 14, and 16 days. The efficacies were evaluated by quantification of ova degeneration during developmental stages in different time points and egg-hatch assay. The flukicidal effects were observed by mortality assay in 5, 10, 20, 40, 80, 160, 320, and 640 min incubations followed by scanning electron microscopy for surface morphology and histology of the fluke's transversal sections.

Results

The concentration of 5% A. vulgaris showed the strongest ovicidal activities. The percentage of hatching ova on day 16 at concentrations of 5%, 2.5%, and 1.25% were 3.33%, 6.67%, and 16.67%. These ova hatch assay showed a significant reduction (p < 0.001) compared to untreated control. The flukicidal effect was significant (p < 0.001) at a concentration of 20%, with a mortality rate reaching 66.67% in the 40 min of incubation time. The surface properties of the adult worms, including the spine, tegument, acetabulum, intestine, and vitelline follicles, were disintegrated.

Conclusion

The results showed that A. vulgaris has the potential ovicidal and flukicidal properties to F. gigantica. The active compounds remained necessary to be elucidated further and its modes of action would be interesting to be predicted by molecular docking modeling.

Impact of helminth-microbiome interactions on childhood health and development-A clinical perspective

Humans have co-existed with parasites for virtually the entirety of our existence as a species. Today, nearly one third of the human population is infected with at least one helminthic species, most of which reside in the intestinal tract, where they have co-evolved alongside the human gut microbiota (GM). Appreciation for the interconnected relationship between helminths and GM has increased in recent years. Here, we review the evidence of how helminths and GM can influence various aspects of childhood development and the onset of paediatric diseases. We discuss the emerging evidence of how many of the changes that parasitic worms inflict on their host is enacted through gut microbes. In this light, we argue that helminth-induced microbiota modifications are of great importance in both facing the global challenge of overcoming parasitic infections, and in replicating helminthic protective effects against inflammatory diseases. We propose that deepening our knowledge of helminth-microbiota interactions will uncover novel, safer and more effective therapeutic strategies in combatting an array of childhood disorders.