Search Results (55)

The zoonotic disease fasciolosis poses a significant global threat to both humans and livestock. The causative agent of fasciolosis is Fasciola hepatica, which is commonly referred to as liver fluke. The emergence of drug resistance has underscored the urgent need for new therapeutic treatments against F. hepatica. The tegument surface of F. hepatica is characterized by a dynamic syncytial layer surrounded by a glycocalyx, which serves as a crucial interface in host–parasite interactions, facilitating functions such as nutrient absorption, sensory input, and defense against the host immune response. Despite its pivotal role, only recently have we delved deeper into understanding glycans at the host–parasite interface and the glycosylation of hidden antigens. These glycan antigens have shown promise for vaccine development or as targets for drug manipulation across various pathogenic species. This review aims to consolidate current knowledge on the glycosylation of F. hepatica, exploring glycan motifs identified through generic lectin probing and mass spectrometry. Additionally, it examines the interaction of glycoconjugates with lectins from the innate immune systems of both ruminant and human host species. An enhanced understanding of glycans’ role in F. hepatica biology and their critical involvement in host–parasite interactions will be instrumental in developing novel strategies to combat these parasites effectively. In the future, a more comprehensive approach may be adopted in selecting and designing potential vaccine targets, integrating insights from glycosylation studies to improve efficacy. Full article

Fasciola hepatica remains a global health and economic concern, and treatment still relies heavily on triclabendazole. At the parasite–host interface, F. hepatica calcium-binding proteins (FhCaBPs) have a unique EF-hand/DLC-like domain fusion found only in trematodes. This makes it a parasite-specific target for small compounds and vaccinations. To enable novel therapeutic strategies, we report the first elevated-resolution structure of a full-length FhCaBP4. The apo structure was determined at 1.93 Å resolution, revealing a homodimer architecture that integrates an N-terminal, calmodulin-like, EF-hand pair with a C-terminal dynein light chain (DLC)-like domain. Structure-guided in silico mutagenesis identified a flexible, 16-residue β4–β5 loop (LTGSYWMKFSHEPFMS) with an FSHEPF core that demonstrates greater energetic variability than its FhCaBP2 counterpart, likely explaining the distinct ligand-binding profiles of these paralogs. Molecular dynamics simulations and AlphaFold3 modeling suggest that EF-hand 2 acts as the primary calcium-binding site, with calcium coordination inducing partial rigidification and modest expansion of the protein structure. Microscale thermophoresis confirmed calcium as the major ligand, while calmodulin antagonists bound with lower affinity and praziquantel demonstrated no interaction. Thermal shift assays revealed calcium-dependent stabilization and a merger of biphasic unfolding transitions. These results suggest that FhCaBP4 functions as a calcium-responsive signaling hub, with an allosterically coupled EF-hand–DLC interface that could serve as a structurally tractable platform for drug targeting in trematodes. Full article

Fistulina hepatica (Schaeff.) With. and Clitocybe nuda (Bull.) H.E. Bigelow & A.H. Sm. are wild edible mushrooms with nutritional and functional potential that remain insufficiently characterized. This study provides the first comparative assessment of their nutritional profiles, phenolic composition, and antioxidant activity, using specimens collected from Montesinho Natural Park (Portugal). Proximate composition, organic and phenolic acids, free sugars, and fatty acids were analyzed by chromatographic methods, and antioxidant capacity was assessed through OxHLIA and TBARS assays. F. hepatica showed higher carbohydrates (9.3 ± 0.2 g/100 g fw) and estimated energy values (43 ± 1 kcal/100 g fw), increased phenolic acids content (2.7 ± 0.1 mg/g extract), and the exclusive presence of p-coumaric and cinnamic acids, along with OxHLIA activity (IC₅₀ = 126 ± 5 µg/mL at Δt = 60 min). C. nuda displayed higher protein (2.5 ± 0.1 g/100 g dw) and quinic acid contents (4.13 ± 0.02 mg/g extract), a PUFA-rich profile, and greater TBARS inhibition (EC₅₀ = 303 ± 17 µg/mL). These findings highlight distinct and complementary bioactive traits, supporting their valorization as natural functional ingredients. Their compositional features offer promising applications in sustainable food systems and nutraceutical development, encouraging further investigations into safety, bioaccessibility, and formulation strategies. Notably, F. hepatica is best consumed at a young developmental stage, as its sensory properties tend to decline with maturity. Full article

Trematode infections caused by Fasciolidae and Paramphistomidae remain widespread in livestock, resulting in substantial economic losses. The two distinct fluke families are difficult to distinguish morphologically, and molecular identification provides the most reliable means of accurate diagnosis. In Ecuador, however, molecular data on these parasites are scarce. In this study, we collected trematodes from cattle rumen and bile ducts, molecularly identified them, and assessed their phylogenetic relationship to Fasciola hepatica to determine their introduction pathways into South America. Genomic DNA was extracted, and PCR was used to amplify the ITS2 (~500 bp) and COXI (~266 bp) regions; all amplicons were Sanger-sequenced. Phylogenetic trees for both markers were constructed using a Maximum Likelihood approach with 1000 bootstrap replicates in CIPRES v3.3. The rumen fluke exhibited 99% ITS2 and COXI similarity to an Indian Cotylophoron cotylophorum strain, while the bile-duct fluke showed 99% ITS2 and 100% COXI similarity to F. hepatica isolates from Australia and Nigeria, respectively. Distinct single-nucleotide polymorphisms (SNPs) in the ITS2 chromatograms suggest a diploid genome structure in both trematode species. This is the first report of C. cotylophorum in Ecuador, and its presence may be linked to the late 19th-century introduction of Zebu cattle (Bos taurus indicus) from India. Full article

(1) Background: As a prominent zoonotic parasitic disease, fascioliasis threatens the sustainable development of animal husbandry and public health. Current research focuses mainly on individual species (parasite or intermediate host), neglecting systematic evaluation of the transmission chain and exposure risks to animal husbandry. Thus, comprehensive studies are urgently needed, especially in the ecologically fragile alpine region of the Qinghai-Tibet Plateau; (2) Methods: Distribution data of Radix spp. and Fasciola hepatica in the Qinghai-Tibet Plateau and adjacent areas were gathered to establish a potential distribution model, which was overlaid on a map of livestock farming in the region; (3) Results: The key environmental factors influencing Radix spp. distribution were temperature seasonality (21.4%), elevation (16.4%), and mean temperature of the driest quarter (14.7%). For F. hepatica, the main factors were elevation (41.3%), human footprint index (30.5%), and Precipitation of the driest month (12.1%), with all AUC values exceeding 0.9. Both species exhibited extensive suitable habitats in Qinghai and Tibet, with higher F. hepatica transmission risk in Qinghai than Tibet; (4) Conclusions: The significant transmission risk and its impacts on the livestock industry in the Qinghai-Tibet Plateau highlight the need for proactive prevention and control measures. This study provides a scientific foundation for targeted alpine diseases control, establishes an interdisciplinary risk assessment framework, fills gaps in high-altitude eco-epidemiology, and offers insights for ecological conservation of the plateau. Full article

Background/Objectives: Vaccine immunogenicity is often suboptimal in vulnerable populations such as the elderly, infants, and individuals in low- and middle-income countries. One contributing factor may be pre-existing immunomodulatory conditions, including helminth infections. This study investigates the impact of Fasciola hepatica (F. hepatica) derived molecules on the early humoral response to the COVID-19 mRNA vaccine Comirnaty^® in a mouse model. Methods: BALB/c mice were pretreated with a F. hepatica protein extract (FH) or complete Freund’s adjuvant (CFA) prior to vaccination. Cytokine production and antibody responses were assessed at 0, 14, and 21 days post-vaccination (dpv) through serum analysis and ex vivo splenocyte stimulation with the SARS-CoV-2 receptor-binding domain (RBD) or LPS. Results: At 0 dpv, FH-treated mice showed increased serum IL-10, while CFA treatment induced IL-12. FH- but not CFA-treated splenocytes secreted IL-10 upon RBD or LPS stimulation. At 21 dpv, FH-treated mice lacked IFN-γ production but maintained IL-10 and showed elevated IL-4, consistent with a Th2-skewed profile. Although total anti-RBD IgG levels were similar between groups, FH-treated mice exhibited reduced IgG avidity and a higher IgG1/IgG2 ratio. CFA-treated mice showed delayed avidity maturation. Conclusions: Prior exposure to F. hepatica antigens can modulate the early immune response to Comirnaty^®, affecting both cellular activation and antibody quality. This altered response may reflect a reduced early protective capacity of the vaccine, which might need to be considered when designing or evaluating vaccination strategies using mRNA vaccines in helminth-endemic regions. Full article

Background/Objectives: In the past, FhSAP-2, an 11.5 kDa recombinant protein belonging to the Fasciola hepatica saposin-like/NK-lysin family, has been shown to induce over 60% partial protection in immunized rabbits and mice when challenged with F. hepatica metacercariae. However, despite FhSAP-2 being a promising vaccine candidate, its hydrophobic nature has made its purification a challenging process. The present study aimed to determine whether a modified 9.8 kDa variant of protein (mFhSAP-2), lacking a string of 16 hydrophobic amino acids at the amino terminus and a dominant Th1 epitope, could retain its immunogenic and Th1-inducing properties. Methods: RAW264.7 cells were stimulated with mFhSAP-2, and TNFα levels were determined. C57BL/6 mice were immunized with mFhSAP-2 alone or emulsified with Montanide ISA50. Total anti-mFhSAP-2 IgG subtypes, along with their avidity and titers, were measured using ELISA. The T cell proliferation index and levels of CD4+/CD8+ and IFNγ/IL-4 ratios were determined. Results: In vitro, mFhSAP-2 induced dose-dependent TNFα production in RAW264.7 cells. In vivo, mice immunized with mFhSAP-2 or mFhSAP-2+ISA50 developed high-avidity IgG2a and IgG2c antibodies at levels that were significantly higher than IgG1 antibody levels. However, the mFhSAP-2+ISA50 formulation induced higher and more homogenous antibody titers than mFhSAP-2, suggesting that an adjuvant may be required to enhance mFhSAP-2 immunogenicity. Immunization with mFhSAP-2+ISA50 also induced significantly higher activated CD4+/CD8+ T cell ratios and IFNγ/IL-4 ratios compared to naïve mice. Conclusions: Our results demonstrate that mFhSAP-2 retained its immunogenicity and Th1-polarizing properties, which were enhanced by the Montanide ISA50 adjuvant. The present study highlights the feasibility of inducing Th1-associated immune responses in mice using mFhSAP-2 as an antigen. Further studies are required to assess the potential application of the mFhSAP-2+ISA50 formulation as a vaccine against F. hepatica in natural hosts such as cattle and sheep, which could contribute to improved control and aid in the prevention and eradication of F. hepatica infection. Full article

The trematodes Fasciola hepatica and F. gigantica are transmitted by lymnaeid snails and cause fascioliasis in livestock and humans. Human infection is emerging in southern and southeastern Asia. In India, the number of case reports has increased since 1993. This multidisciplinary study analyzes the epidemiological scenario of human infection. The study reviews the total of 55 fascioliasis patients, their characteristics, and geographical distribution. Causes underlying this emergence are assessed by analyzing (i) the climate change suffered by India based on 40-year-data from meteorological stations, and (ii) the geographical fascioliasis hotspots according to archeological–historical records about thousands of years of pack animal movements. The review suggests frequent misdiagnosis of the wide lowland-distributed F. gigantica with F. hepatica and emphasizes the need to obtain anamnesic information about the locality of residence and the infection source. Prevalence appears to be higher in females and in the 30–40-year age group. The time elapsed between symptom onset and diagnosis varied from 10 days to 5 years (mean 9.2 months). Infection was diagnosed by egg finding (in 12 cases), adult finding (28), serology (3), and clinics and image techniques (12). Climate diagrams and the Wb-bs forecast index show higher temperatures favoring the warm condition-preferring main snail vector Radix luteola and a precipitation increase due to fewer rainy days but more days of extreme rainfall, leading to increasing surface water availability and favoring fascioliasis transmission. Climate trends indicate a risk of future increasing fascioliasis emergence, including a seasonal infection risk from June–July to October–November. Geographical zones of high human infection risk defined by archeological–historical analyses concern: (i) the Indo-Gangetic Plains and corridors used by the old Grand Trunk Road and Daksinapatha Road, (ii) northern mountainous areas by connections with the Silk Road and Tea-Horse Road, and (iii) the hinterlands of western and eastern seaport cities involved in the past Maritime Silk Road. Routes and nodes are illustrated, all transhumant–nomadic–pastoralist groups are detailed, and livestock prevalences per state are given. A baseline defining areas and seasons of high infection risk is established for the first time in India. This is henceforth expected to be helpful for physicians, prevention measures, control initiatives, and recommendations for health administration officers. Full article

Fasciola hepatica is a parasitic trematode responsible for fascioliasis, a significant zoonotic disease affecting livestock worldwide, as well as humans. This study identifies peptides with potential for use in vaccines against Fasciola hepatica and validates multi-epitope constructs from those peptides in vitro. Putative protein sequences derived from the genome of F. hepatica were integrated with phase-specific transcriptomic data to prioritize highly expressed proteins. Among these, extracellular proteins were selected using DeepLoc 2.0 and strong binding affinities across diverse human and murine alleles were predicted with the IEDB MHC II tool. Peptides were further selected based on their toxicity, immunogenicity, and allergenicity. Finally, 55 high-priority candidates were obtained. To express these candidates, mRNA constructs encoding various combinations of these peptides were designed, synthesized using in vitro transcription with T7 or SP6 RNA polymerases, and transfected into cells for expression analysis. SP6 polymerase produced proper capping using CleanCapAG and was far superior in transcribing peptide constructs. Peptides fused in frame with eGFP were expressed efficiently, particularly when peptides were positioned at the 3′ terminus, opening a new field of peptide vaccines created using mRNA technology. Full article

Fasciolosis is a neglected tropical disease caused by helminth parasites of the genus Fasciola spp., including Fasciola hepatica (F. hepatica) and Fasciola gigantica (F. gigantica), being a major zoonotic problem of human and animal health. Its control with antihelminthics is becoming ineffective due to the increase in parasite resistance. Developing new therapeutic protocols is crucial to a deeper knowledge of the molecular bases in the host–parasite interactions. The high-throughput omics technologies have dramatically provided unprecedented insights into the complexity of the molecular host–parasite crosstalk. MicroRNAs (miRNAs) are key players as critical regulators in numerous biological processes, modifying the gene expression of cells by degradation of messenger RNA (mRNA), regulating transcription and translation functions, protein positioning, cell cycle integrity, differentiation and apoptosis. The large-scale exploration of miRNAs, including the miRNome, has offered great scientific knowledge of steps in fasciolosis, further scrutinizing the pathogenesis, the growth and development of their strains and their interaction with the host for the survival of the different parasite stages. This review compiles the updated knowledge related to miRNAs involved in fasciolosis and the generated miRNome, highlighting the importance of these key molecules in the host–parasite interactions and the pathogenesis of Fasciola spp. directing towards the development of new biotherapeutic protocols for the control of fasciolosis. Full article

Fasciola hepatica is a parasitic trematode that causes fasciolosis in sheep, provoking a decrease in their reproductive capacity, weight gain, meat and milk production, and wool quality. In the pathogenesis of F. hepatica, the penetration and migration of parasitic stages through the liver provoke intense inflammatory immune responses and tissue damage. The aim of this study was to investigate the cytotoxic effects of Fascila hepatica-induced ovine NETs in exposed hepatocytes in vitro, and to analyze whether F. hepatica antigens (FhAg) trigger the release of ovine NETs under hypoxic conditions as well as the roles of matrix metalloproteinase-9 (MMP-9) and CD11b in this cellular process in vitro. Here, isolated ovine PMNs were co-cultured with FhAg under hypoxia (5% O₂) and NETs were visualized via immunofluorescence analyses, confirming their classical characteristics. The quantification of NETs in response to FhAg in hypoxic conditions significantly enhanced the formation of anchored and cell-free NETs (p < 0.01), and NADPH oxidase (NOX) inhibitor diphenylene iodonium (DPI) significantly reduced their production (p < 0.05). Furthermore, the cytotoxic effect of NETs on hepatic cells was determined by using a live/dead-staining with Sytox Orange, thereby demonstrating that FhAg-induced NETs are cytotoxic for hepatic cells (p = 0.001). We additionally analyzed PMN supernatants to determine the enzymatic activity of MMP-9, observing that FhAg exposure enhances MMP-9 release in ovine PMNs (p < 0.05) but not in bovine PMNs. Interestingly, by using flow cytometric analysis, we determined that the exposure of PMNs to FhAg does not increase the CD11b surface expression of ovine PMNs. This could be an effect of the activation of other surface receptors or transcription factors involved in F. hepatica-induced NETosis. Consequently, we hypothesize that F. hepatica-induced NETs play a role in the pathogenesis of fasciolosis, contributing to liver tissue damage if released in an uncontrolled manner. Full article

Fasciola hepatica is a liver fluke that resides in the bile ducts of various mammals. The parasitosis leads to economic losses in animal production estimated at USD 3.2 billion annually. It is also considered a zoonosis of great significance and a problem for public health affecting 2.4 million people worldwide. Nevertheless, besides the negative aspects of infestation, the antigens released by the fluke, F. hepatica Excretory-Secretory Products (Fh-ES) contain several immunomodulatory molecules that may be beneficial during the course of type I diabetes, multiple sclerosis, ulcerative colitis, or septic shock. This phenomenon is based on the natural abilities of adult F. hepatica to suppress proinflammatory responses. To underline the molecular basis of these mechanisms and determine the role of microRNA (miRNA) in the process, lipopolysaccharide (LPS)-activated THP-1 macrophages were stimulated with Fh-ES, followed by miRNA microarray analyses. Surprisingly, no results indicating changes in the miRNA expression profile were noted (p < 0.05). We discuss potential reasons for these results, which may be due to insufficient sensitivity to detect slight changes in miRNA expression or the possibility that these changes are not regulated by miRNA. Despite the negative data, this work may contribute to the future planning of experiments by other researchers. Full article

Castanea sativa is a high-value tree species whose stands have faced significant threats over the past century. The occurrence of one such threat, Chestnut Red Stain—a heartwood discoloration caused by the fungus Fistulina hepatica—has recently increased. This disease devalues the timber by up to 70% due to the rejection of stained wood by the industry. This study aimed to evaluate the effects of three management strategies on the occurrence of F. hepatica in chestnut coppice stands. Additionally, the co-occurrence of F. hepatica and Cryphonectria parasitica, both highly prevalent in the study area, was assessed. In 2013, three different silvicultural treatments were applied to five plots. Seven years later, the stand characteristics were measured, and the incidence of F. hepatica was evaluated using molecular tools. Data modeling revealed that the quadratic mean diameter before the interventions was related to the incidence of F. hepatica. Our results suggest that the thinning at earlier stand stages may be more critical than the type or intensity of the thinning in reducing the incidence of the fungus in the mid-term. This finding provides forest managers with new guidance to improve silvicultural treatments and prevent F. hepatica damage. Full article

Zoo conditions are unique for reindeer, since domestic reindeer are not kept in captive facilities like cattle. In the zoo, reindeer are usually surrounded by many different animals that they would never encounter naturally. Thus, they might be infected with new helminths. Numerous petting zoos raise concerns about the safety of tactile interactions for human visitors. Our study is the first large-scale one. Qualitative and quantitative fecal analyses were carried out for 233 reindeer distributed over 50 Russian zoos according to the National Standard of the Russian Federation (GOST R 54627-2011) Ruminant animals—Methods of Laboratory Helminthological Diagnostics. Where possible, DNA analyses of helminths were performed targeting internal transcribed spacer region. As a result, F. hepatica, Paramphistomum sp., Moniezia sp. (including M. expansa), gastrointestinal strongylids (including Nematodirus spp.), Dictyocaulus sp., E. rangiferi, Trichuris sp., and Capillaria sp. were found in 106 (45%) zoo reindeer. All these helminths were previously reported in reindeer and pose no direct danger for humans. The intensity of invasions was mostly low. Fecal examination might be considered as an indirect method for mange diagnostics, as Chorioptes and Demodex mites were found in reindeer fecal samples. The latter may represent a novel species of mite specific for reindeer. Full article

Background: Transposable elements (TEs) are major components of eukaryotic genomes. The extensive body of evidence suggests that although they were once considered “genomic parasites”, transposons and their transcripts perform specific functions, such as regulation of early embryo development. Understanding the role of TEs in such parasites as trematodes is becoming critically important. Fasciola hepatica, a parasite affecting humans and livestock, undergoes a complex life cycle in diverse environments and hosts, and knowledge about its life cycle regulation is scarce so far. Methods: We summarized the data regarding the repetitive elements in F. hepatica and conducted bulk RNA-seq analysis across its life cycle stages. TE expression profiles were analyzed, focusing on differential expression and potential homology with previously described long non-coding RNAs (lncRNAs). Results: Differential expression analysis revealed stage-specific TE transcription patterns, notably peaking during egg and metacercariae stages. Some TEs showed homology with known lncRNAs and contained putative transcription factor binding sites. Interestingly, TE transcription levels were highest in eggs and metacercariae compared to adults, suggesting regulatory roles in trematode life cycle transitions. Conclusions: These findings suggest that TEs may play roles in regulating trematode life cycle transitions. Moreover, TE homology with lncRNAs underscores their significance in gene regulation. Full article