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Although the negative impact of liver fluke (Fasciola hepatica) infection on production and health in cattle is generally accepted, results of individual research have been variable, ranging from important negative impacts on the animal to minimal or no impact. To add information on the impact of F. hepatica infection in growing cattle, weight gain and liver weight of young experimentally infected animals from seven controlled efficacy studies were analyzed. In each study, fluke naïve animals were inoculated with approximately 450 to 500 F. hepatica encysted metacercariae, blocked on body weight and randomly assigned into one untreated group (controls) and groups which were administered an experimental flukicide when the flukes were 4 weeks old (migrating) and sacrificed 8 weeks thereafter (12 weeks after inoculation). Data of groups which demonstrated >90% reduction of fluke counts following treatment and groups left untreated (total 103 and 47 animals, respectively) were compared. There was a significant (p < 0.0001) negative association between fluke count and weight gain while fluke count and liver weight and fluke count and relative liver weight were positively associated (p < 0.0001). Over the 8-week post-treatment period, flukicide-treated cattle had almost 15% more weight gain than the controls (50.9 kg vs. 44.4 kg; p = 0.0003). Absolute and relative liver weight was significantly (p < 0.0001) lower in flukicide-treated compared to untreated cattle. Overall, this analysis provided evidence of a substantial negative effect of early (migrating) liver fluke infection on the growth of young cattle, likely due to pathology of the liver and associated reduction in its function as the central organ for bioenergy and protein metabolism. [ABSTRACT FROM AUTHOR]

Considering the original nature of carnivorism among dogs and cats, nowadays these pets are increasingly fed BARF (Biologically Appropriate Raw Food/Bone And Raw Food) diet to improve their health conditions. However, this diet may also carry health risks, such as vitamin or mineral deficiencies, and infection with pathogens including parasites. In our study, fecal samples of 89 pet animals kept on BARF diet were subjected to coprological examination followed by molecular analyses. Six of them shed eggs of Dicrocoelium dendriticum. This result was confirmed with PCR and sequencing, and in one case, the DNA of Fasciola hepatica was also demonstrated. In addition, oocysts of Cystoisospora canis, a Cystoisospora ohioensis-like sp. and Eimeria stiedai, as well as sporocysts of a Sarcocystis sp. were also detected. All samples were negative for Neospora caninum and Toxoplasma gondii. In conclusion, no evidence was found for the infection of BARF-fed dogs and cats with parasites that are usually associated with this diet and considered as clinico-pathological risk factors for these pets themselves (e.g., N. caninum, T. gondii). However, fluke eggs (probably originating from ruminants) and oocysts of E. stiedai (from rabbit liver in the food) were demonstrated as pseudoparasites. These species are usually not considered among parasite-associated risks of BARF-feeding, implying that other animals living near BARF-fed pets are neglected in this context. However, where intermediate hosts of D. dendriticum occur in urban areas, BARF-feeding may indirectly affect later other dogs and cats. It was also shown here that BARF-feeding may contribute to the contamination of the environment with E. stiedai oocysts, thus increasing the risks of biliary coccidiosis in nearby living pet rabbits that would otherwise not have access to oocysts of E. stiedai. [ABSTRACT FROM AUTHOR]

The objective of this work was to evaluate the effect of the ethyl acetate extract from A. ludoviciana (EALM) and artemisinin against adult parasites and eggs of F. hepatica. For the ovicidal assay, cell culture plates with 24 wells were used, and 90 to 110 F. hepatica eggs were placed in each well. The eggs were exposed to concentrations of 100, 200, 300, 400, and 500 mg/L EALM and incubated for 16 days. Additionally, triclabendazole (TCBZ) was used as a reference drug at concentrations of 10 and 50 mg, and the response of artemisinin at concentrations of 10 and 20 mg was simultaneously assessed. Adult flukes were exposed to concentrations of 125, 250, 375, and 500 mg/L EALM. The results of the ovicidal action of EALM on the eggs showed that concentrations greater than 300 mg/L were significant, with ovicidal percentages greater than 60% observed on day 16 of incubation (p < 0.05). The maximum efficiency of EALM on adult flukes was reached 72 h post-exposure at a concentration of 125 mg/L (p < 0.05). [ABSTRACT FROM AUTHOR]

The aim of this study was to characterize the Tunisian Fasciola spp. flukes by morphometric and molecular analyses. Flukes were collected from livers of sheep slaughtered in Sejnane slaughterhouses (Bizerte gouvernorate, Northwest Tunisia) between January and March 2021. Five morphometric parameters were determined for all the liver flukes, as follows: (i) total body length (BL), (ii) distance between ventral sucker and the tail (VS-T), (iii) distance between oral sucker and ventral sucker (OS-VS), (iv) abdomen diameter (AD), (v) tail diameter (TD) and the body length to width ratio (BL/BW). Molecular identification of the fluke specimens was carried out by polymerase chain reaction, restriction fragment polymorphism (PCR-RFLP) of a 680 bp sequence of the internal transcribes spacer 1 (ITS1) gene and by amplification, sequencing, and phylogenetic analysis of a 500 bp sequence of the ITS2 gene. Morphometric measurements showed that the mean of the total body length of the adult flukes was 21.1 ± 2.7 mm with minimum and maximum lengths of 13 and 31 mm, respectively. The PCR-RFLP analysis revealed a single profile consisting of three bands of approximately 370, 100, and 60 bp. Fasciola sequences described in the present study (GenBank numbers: OQ457027 and OQ457028) showed 99.58–100% identity to Fasciola hepatica. In conclusion, the results of this study show that molecular and phylogenetic analyses confirm the presence of a single species of F. hepatica in the Sejnane region Northwest of Tunisia. However, further studies are needed to identify the occurrence of Fasciola species in other Tunisian regions. [ABSTRACT FROM AUTHOR]

Fasciola hepatica is a trematode leading to heavy economic setbacks to the livestock sector globally. The population's genetic information and intimate kinship level are frequently assessed using analysis of mitochondrial DNA. In this analysis, we retrieved cox1 (n = 247) and nad1 (n = 357) sequences of F. hepatica from the NCBI GenBank database and aligned the sequences with the respective reference sequences using MEGA software. The median joining network was drawn using PopArt software while neutrality and diversity indices were estimated with the help of DnaSp software. Neighbor-joining phylogenetic tree was constructed using the MEGA software package. A total of 46 and 98 distinctive haplotypes were observed for cox1 and nad1 genes, respectively. Diversity indices indicated high haplotype and nucleotide diversities in both genes. Positive Tajima's D and Fu's Fs values were found for the entire population of both the genes under study. The cox1 and nad1 gene segments in this study showed high Tajima's D values, suggesting a low likelihood of future population growth. The Tajima's D value of the nad1 gene sequence is lower (2.14910) than that of the cox1 gene sequence (3.40314), which suggests that the former is growing at a slower rate. However, the region-wise analysis revealed that both the cox1 and nad1 genes showed deviation from neutrality suggesting a recent population expansion as a result of an excess of low-frequency polymorphism. Furthermore, the overall host-wise analysis showed positive and significant Tajima's D values for the cox1 and nad1 gene sequences. To the best of our knowledge, this is the first attempt to provide insights into genetic variations and population structure of F. hepatica at a global scale using cox1 and nad1 genes. Our findings suggest the existence of specific variants of F. hepatica in different parts of the world and provide information on the molecular ecology of F. hepatica. The results of this study also mark a critical development in upcoming epidemiological investigations on F. hepatica and will also contribute to understanding the global molecular epidemiology and population structure of F. hepatica. [ABSTRACT FROM AUTHOR]

Buffaloes, as highly susceptible definitive hosts of Fasciola gigantica, suffer from a high infection rate of fasciolosis, which causes enormous economic losses. Repeat infection is responsible for this high rate; thus, elucidating the protective immunity mechanism in repeat infection is decisive in fasciolosis prevention. Herein, a secondary experimental infection model was established to preliminarily reveal the protective immunity that occurs in repeat infection. In brief, animals were assigned to three groups: group A (uninfected control), group B (primary infection) and group C (secondary infection). Buffaloes were autopsied 20 weeks post-infection for measurements of the recovered flukes and hepatic examination. In addition, the detection of specific antibody (IgG) responses to F. gigantica excretory-secretory product (FgESP) throughout the whole period and weight gain throughout the first 4 months as a percentage (%) of the starting weight were also determined. The serum hepatic enzyme gamma glutathione transferase (GGT) levels were monitored to assess hepatic damage throughout the study period. Infection establishment was compared between group B and group C. Similar specific IgG patterns were observed between group B and group C, and hepatic damage was more severe in group C than group B. Significant differences in weight gain as a percentage of the start weight were observed between group A and group B at the 3rd and 4th months postprimary infection, while significant differences were not observed between group A and group C or group B and group C. Our results suggest that challenge infection cannot induce resistance against F. gigantica in buffaloes, which is consistent with the protective immunity against Fasciola hepatica reinfection observed in sheep and goats. [ABSTRACT FROM AUTHOR]

Understanding drug penetration, distribution, and metabolization is fundamental for understanding drug efficacy. This also accounts for parasites during antiparasitic treatment. Recently, we established matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) in blood flukes and liver flukes. This label-free technique is capable of visualizing the molecular distribution of endogenous and exogenous molecules, such as drug compounds. Here, we conducted atmospheric-pressure scanning microprobe MALDI MSI (AP-SMALDI MSI) of tissue sections of adult Fasciola hepatica that have been treated in vitro with 100 µM of triclabendazole (TCBZ), the drug of choice for treatment of fasciolosis, and its main metabolite triclabendazole sulfoxide (TCBZ-SO). Measurements covered an m/z mass range of 250–1,000 and provided a high spatial resolution using a pixel size of 10 µm. To support the interpretation of drug distribution, we first identified endogenous lipids that mark characteristic tissues such as the gastrodermis, the tegument, and the parenchyma. The obtained results suggested an early tegumental route of TCBZ uptake within 20 min, followed by spreading throughout the parasite after 4 h, and an even distribution in most tissues after 12 h. This coincided with a strong reduction of parasite vitality. TCBZ-SO treatment demonstrated the accumulation of this metabolite in the same tissues as the parent drug compound. These data demonstrate the auspicious potential of MALDI MSI to visualize uptake and distribution patterns of drugs or drug-candidate compounds in parasites, which might contribute to preclinical drug discovery in liver fluke research and beyond. [ABSTRACT FROM AUTHOR]

The aim of the present study was to determine the effective dose of fosfatriclaben through a field study in sheep naturally infected with F. hepatica. Thirty crossbred sheep positive for fluke eggs were selected for inclusion in the trial. On day 0, 5 groups of 6 animals each were formed for treatments: group 1 (G1), G2, and G3 received fosfatriclaben at 4, 6, and 8 mg/kg/IM, respectively. G4 received triclabendazole at 10 mg/kg/PO, and G5 was the untreated control group. Fecal samples of the sheep were analyzed to count the number of fluke eggs to evaluate the percentage of egg reduction. Twenty-one days after treatment, all sheep were humanely euthanized to extract the flukes from the bile ducts. They were counted to assess the percentage of fluke reduction. Fosfatriclaben reduced fluke eggs by 99.6, 99.6, and 100% and flukes by 94.3, 100, and 100%, respectively. Triclabendazole reduced fluke eggs by 95.2% and flukes by 100%. The fosfatriclaben injectable prodrug showed a high fasciolicidal efficacy similar to triclabendazole, with advantages over its predecessor, since only half the dose as compared to triclabendazole was required to remove eggs and flukes in the sheep that were studied. [ABSTRACT FROM AUTHOR]

Fasciola hepatica (liver fluke), a significant threat to food security, causes global economic loss for the livestock industry and is re-emerging as a foodborne disease of humans. In the absence of vaccines, treatment control is by anthelmintics; with only triclabendazole (TCBZ) currently effective against all stages of F. hepatica in livestock and humans. There is widespread resistance to TCBZ and its detoxification by flukes might contribute to the mechanism. However, there is limited phase I capacity in adult parasitic helminths with the phase II detoxification system dominated by the soluble glutathione transferase (GST) superfamily. Previous proteomic studies have demonstrated that the levels of Mu class GST from pooled F. hepatica parasites respond under TCBZ-sulphoxide (TCBZ-SO) challenge during in vitro culture ex-host. We have extended this finding by exploiting a sub-proteomic lead strategy to measure the change in the total soluble GST profile (GST-ome) of individual TCBZ-susceptible F. hepatica on TCBZ-SO-exposure in vitro culture. TCBZ-SO exposure demonstrated differential abundance of FhGST-Mu29 and FhGST-Mu26 following affinity purification using both GSH and S-hexyl GSH affinity. Furthermore, a low or weak affinity matrix interacting Mu class GST (FhGST-Mu5) has been identified and recombinantly expressed and represents a new low-affinity Mu class GST. Low-affinity GST isoforms within the GST-ome was not restricted to FhGST-Mu5 with a second likely low-affinity sigma class GST (FhGST-S2) uncovered. This study represents the most complete Fasciola GST-ome generated to date and has supported the potential of subproteomic analyses on individual adult flukes. [ABSTRACT FROM AUTHOR]

The objective of the present study was to determine the seroprevalence of Fasciola hepatica infection in horses, donkeys and mules from different climate regions in two states of Mexico. A total of 594 serum samples were analysed for immunoglobulin G (IgG) antibodies using enzyme-linked immunosorbent assay (ELISA), with excretory-secretory (E/S) products as the antigen. The diagnostic sensitivity and specificity of serum IgG ELISA were 100% and 97.2%, respectively. We collected data using a questionnaire. The overall prevalence of the parasite in equids between May 2018 and April 2019 was 13.1% (78 out of 594). The highest prevalence was found in mules (17.9%), followed by that in donkeys (13.9%) and horses (10.4%). In addition, the highest percentage of positive equines was detected in samples from the tropical climate (17.5%). The identification of risk factors was assessed by bivariate logistic regression analysis. Mules had 8.608 times higher risk for F. hepatica infections as compared with horses (odds ratio (OR) 8.608; 95% confidence interval (CI): 2.809–26.377), while the OR for 6–10-year-old equines was 93.375 compared with that of young equines (≤ 5 years old) (OR 93.375; 95% CI: 11.075–787.239). Likewise, tropical climate equines had 83.7% increased odds for fasciolosis (OR 1.83). [ABSTRACT FROM AUTHOR]

Fasciola hepatica (F. hepatica) is a well-known zoonotic parasite that is crucial for economic and public health worldwide. Quantitative proteomics studies have been performed on proteins expressed by F. hepatica to investigate the differential expression of proteomes in different growth phases. And the screening of several marker proteins for use as early diagnostic antigens is essential. In this study, high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) was conducted to analyze the differences in the expression of F. hepatica somatic proteins in different growth phases. Furthermore, gene ontology (GO) functional annotation, KEGG metabolic pathway, and clustering analyses were also performed. LC-MS/MS identified 629, 2286, 2254, and 2192 proteins in metacercariae, juvenile flukes 28dpi, immature flukes 59dpi, and adult phases, respectively. GO analysis revealed that differentially expressed proteins (DEPs) were mainly involved in transport, localization, metabolism, enzyme regulation, protein folding and binding, and nucleoside and nucleotide binding. The DEPs were enriched in cells, intracellular components, organelles, cytoplasm, vesicles, and membranes. KEGG pathway annotation results showed that the DEPs were involved in metabolism, genetic information processing, environmental information processing, cellular processes, organismal systems, and other processes. These findings provide a theoretical basis for vaccine development and establishing early diagnostic methods in the future. [ABSTRACT FROM AUTHOR]

In this work, we compare and evaluate the efficiency of fosfatriclaben with three commercial fasciolicides in experimentally infected sheep. Fosfatriclaben is a novel prodrug derived from triclabendazole; it is highly water-soluble with excellent aqueous stability at pH 7, properties that make it ideal for developing intramuscular pharmaceutical compositions in the form of solutions. In order to compare, 30 mixed breed sheep, previously diagnosed negative to fluke eggs, were infected with 200 metacercariae of Fasciola hepatica, twice. Five groups of six animals/each were formed for treatments. Group 1 (G1) was treated with closantel 5% injectable at 5 mg/kg subcutaneously, G2 with clorsulon at 2 mg/kg subcutaneously, G3 with triclabendazole at 12 mg/kg per os, G4 with fosfatriclaben at 6 mg/kg intramuscularly (dose equivalent to triclabendazole content), and G5 remained as the non-treated control. On day 110, fecal samples were examined to determine the percentage of egg reduction after treatment, and sheep were humanely euthanized. The livers were collected, the flukes were extracted, measured, and counted. Efficiency in egg reduction was of 86.8, 90.5, 98.4, and 97.3% for closantel, clorsulon, triclabendazole, and fosfatriclaben, respectively, and efficiency against flukes was of 96.2, 91.9, 99.4, and 95.7%, respectively. No statistical differences were found between treatments. It is concluded that fosfatriclaben at 6 mg/kg intramuscularly presented a high fasciolicide efficiency, similar to the best commercial fasciolicides, having advantage over its predecessor since it uses half of the dose required by triclabendazole to remove flukes in sheep under study. [ABSTRACT FROM AUTHOR]

The worldwide occurring common liver fluke Fasciola hepatica can infect humans and animals and leads to considerable illness and economic loss annually. The aim of this study was to determine the genetic diversity of F. hepatica in Austria. In total, 31 adult flukes isolated from cattle from various regions in Austria were investigated for their cytochrome oxidase subunit 1 (cox1) and nicotinamide dehydrogenase subunit 1 (nad1) gene sequences. It was shown that Austrian isolates of F. hepatica reveal extensive genetic diversity. To the best of our knowledge, these are the first data on the diversity of F. hepatica in Austria. [ABSTRACT FROM AUTHOR]

The liver fluke Fasciola hepatica is the main cause of fasciolosis in North Africa leading to significant economic losses and public health problems. In this study, the ribosomal internal transcribed spacer (ITS), cytochrome c oxidase I (COI), the mitochondrial region spanning the COI-trnT-rrnL, and the NADH dehydrogenase subunit I (NADI) markers were used to characterize Fasciola flukes from Algeria. Fasciola appeared widespread from the east to the west of Algeria. Among 1701 sampled cattle from 8 Algerian provinces, 5% were infected. Using morphological and morphometric analysis, one morphotype of Fasciola was observed. Nuclear ITS marker indicated that all collected flukes belong to F. hepatica. Multiple alignments of ITS dataset revealed two haplotypes, one described here for the first time. Analysis of molecular variance (AMOVA) of mitochondrial markers revealed weak population structure in Algeria. Mismatch distributions, neutrality tests, and median-joining network analysis all were compatible with a recent expansion of Algerian F. hepatica population. Fasciolosis appeared common in Algerian cattle, it seems that the absence of control strategy coupled to the favorable Mediterranean climate may lead to a reconstruction and dispersion of its populations. This study provides important results concerning the genetic characterization and variability of F. hepatica in Algeria as well as the significant role of cattle importation in shaping its dispersal route worldwide. [ABSTRACT FROM AUTHOR]

The objective of this work was to evaluate the effect of the ethyl acetate extract from A. ludoviciana (EALM) and artemisinin against adult parasites and eggs of F. hepatica. For the ovicidal assay, cell culture plates with 24 wells were used, and 90 to 110 F. hepatica eggs were placed in each well. The eggs were exposed to concentrations of 100, 200, 300, 400, and 500 mg/L EALM and incubated for 16 days. Additionally, triclabendazole (TCBZ) was used as a reference drug at concentrations of 10 and 50 mg, and the response of artemisinin at concentrations of 10 and 20 mg was simultaneously assessed. Adult flukes were exposed to concentrations of 125, 250, 375, and 500 mg/L EALM. The results of the ovicidal action of EALM on the eggs showed that concentrations greater than 300 mg/L were significant, with ovicidal percentages greater than 60% observed on day 16 of incubation (p < 0.05). The maximum efficiency of EALM on adult flukes was reached 72 h post-exposure at a concentration of 125 mg/L (p < 0.05)., (© 2023. The Author(s).)

Fasciolosis is an important zoonotic disease caused by the trematode Fasciola hepatica, and it causes great losses in bovine production. The anthelmintic resistance is a major problem in the control of fasciolosis. In this study, the F. hepatica egg development and hatching test (EDHT) was used for the evaluation of the ovicidal activity of commercial drugs, commonly used for treating infected cattle, which reflects F. hepatica anthelminthic resistance in infected bovines, according to recent literature. Bile samples from F. hepatica naturally parasitized cattle were obtained from slaughterhouses in the cities of Lages and Otacílio Costa, Santa Catarina State, Brazil. The bile was washed, the eggs were recovered, quantified, and distributed in universal collectors, with a minimum of 1,000 eggs per vial. Four commercial drugs were used in this study, containing albendazole sulfoxide (ABDZ), closantel (CSTL), nitroxynil (NTXL), and triclabendazole with fenbendazole (TBZF). The drugs were diluted according to the manufacturer instructions. All drugs, and the respective control, were tested in triplicates, with the quantity of recovered eggs determining the number of drugs to be tested. The vials were incubated for 28 days at 27 °C, and the eggs were classified according to their degree of development under a stereomicroscope. In total, 121 egg samples were analyzed. Two samples were identified as resistant to TBZF. Undetermined resistance/susceptibility has been found in two isolates treated with ABDZ, one treated with NTXL and six treated with TBZF. CSTL did not present ovicidal activity and cannot be used in EDHT. This is the first time that commercial drugs were used in F. hepatica EDHT., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Infections caused by Fasciola hepatica are of great importance in the veterinary field, as they cause important economic losses to livestock producers. Serodiagnostic methods, typically ELISA (with either native or recombinant antigens), are often used for early diagnosis. The use of native antigens, as in the MM3-SERO ELISA (commercialized as BIO K 211, BIO-X Diagnostics), continues to be beneficial in terms of sensitivity and specificity; however, there is interest in developing ELISA tests based on recombinant antigens to avoid the need to culture parasites. Of the antigens secreted by adult flukes, recombinant procathepsin L1 (rFhpCL1) is the most commonly tested in ELISA to date. However, although adult flukes produce three different clades of CLs (FhCL1, FhCL2, and FhCL5), to our knowledge, the diagnostic value of recombinant FhCL2 and FhCL5 has not yet been investigated. In the present study, we developed and tested three indirect ELISAs using rFhpCL1, rFhpCL2, and rFhpCL5 and evaluated their recognition by sera from sheep and cattle naturally infected with F. hepatica. Although the overall antibody response to these three rFhpCLs was similar, some animals displayed preferential recognition for particular rFhpCLs. Moreover, for cattle sera, the highest sensitivity was obtained using rFhpCL2 (97%), being equal for both rFhpCL1 and rFhpCL5 (87.9%), after adjusting cut-offs for maximum specificity. By contrast, for sheep sera, the sensitivity was 100% for the three rFhpCLs. Finally, the presence of truncated and/or partially unfolded molecules in antigen preparations is postulated as a possible source of cross-reactivity. [ABSTRACT FROM AUTHOR]

Laboratory diagnosis of sheep fasciolosis is commonly performed by coprological examinations; however, this method may lead to false negative results during the acute phase of the infection. Furthermore, the poor sensitivity of coprological methods is considered to be a paradox in the chronic phase of the infection. In this study, we compared the immunoreactivity of native and recombinant forms of Fasciola hepatica excretory/secretory antigens and determined their capabilities for the development of F. hepatica-specific immunoassays. Immunoreactivity and specificity of recombinant and native forms of F. hepatica antigens, including fatty acid binding protein (FABP), glutathione- S-transferase (GST), and cathepsin L-1 (CL1), in parallel with native forms of FABP and GST, were studied for serodiagnosis of the chronic form of sheep fasciolosis, individually or in combination with each other by enzyme-linked immunosorbent assays (ELISA). The correlation of the findings was assessed by receiver-operator characteristic (ROC); furthermore, the specificity and sensitivity were assessed by Youden's J. Serologic cross-reactivity was evaluated using samples from healthy sheep ( n = 40), Fasciola-infected sheep ( n = 30), and sheep with other parasitic infections ( n = 43). The FABPs were determined to be greater than 95% sensitive for F. hepatica serodiagnosis. The most desirable diagnostic recombinant antigen was rCL1, which showed 100% sensitivity and 97% specificity in ELISA and was capable of discriminating the positive and negative samples by maximum Youden's J results. We conclude that rCL1 can be used for routine serodiagnosis of chronic fasciolosis. Thus, it could be advantageous in development of immunoassays for screening of ovine herds in fasciolosis-endemic areas and as a reliable agent for detection of fasciolosis in non-endemic regions. [ABSTRACT FROM AUTHOR]

Fasciola hepatica are trematodes that reside in the bile ducts of mammals. Infection causes US$3 billion in losses annually in animal production and is considered a zoonosis of growing importance. An under-represented area in F. hepatica research has been the examination of the different immunomodulatory abilities of various parasite isolates on the host immune system. In this paper, this issue was explored, with the bovine macrophage cell line 'BOMA'. The cells were matured by LPS treatment and stimulated with excretory/secretory antigens (ES) from two Fasciola hepatica isolates: a laboratory isolate 'Weybridge' ( Fh-WeyES) and a wild isolate ( Fh-WildES). As expected, stimulation with antigen mixtures with highly similar compositions resulted in mild transcriptomic differences. However, there were significant differences in cytokine levels. Compared to Fh-WeyES, exposure to Fh-WildES upregulated 27 and downregulated 30 genes. Fh-ES from both isolates diminished the release of TNF-α, whereas only Fh-WildES decreased IL-10 secretion. Neither Fh-WeyES nor Fh-WildES had an impact on IL-12 release. Our results indicate that various isolates can have different immunomodulatory abilities and impacts on the bovine immune system. [ABSTRACT FROM AUTHOR]

Liver fluke is a ubiquitous parasite that causes extensive production losses in cattle and is a zoonosis. The aims of this study were to determine the prevalence of fasciolosis in 178 dairy cattle herds in Styria (federal state of Austria) and its influence on production, to detect the risk factors for infection, and to explore effective strategies in management and control. A questionnaire on farm management, prophylaxis, and therapy was developed and applied. Furthermore, production parameters (milk yield, milk protein content, butter fat content, non-return rate 90, calving to conception interval, service period) were recorded for 2014 and 2015, and a commercial ELISA for detection of Fasciola hepatica antibodies was applied in bulk tank milk in March 2014 and March 2015. Analysis of bulk tank milk samples showed a prevalence of 61.3% in 2014 and 45.5% in 2015. No associations could be found between F. hepatica exposure and farm structure or pasture management. Farms with highly positive (optical density ratio (ODR) ≥ 0.6 and lying above the upper interquartile range) antibody levels had a significantly lower annual milk yield of 438 kg per cow per year ( p = 0.045), butterfat content of 0.091% ( p = 0.004), and milk protein content of 0.046% ( p = 0.024). However, fertility parameters were not significantly associated with liver fluke exposure. Anthelmintic treatment led to significantly lower antibody levels in the subsequent year ( p = 0.042) and had a significant influence on protein content in milk ( p = 0.003). This study highlighted the importance of fasciolosis in Austria and its influence on milk production and the need for veterinary advice regarding prophylactic measures to reduce economic losses. [ABSTRACT FROM AUTHOR]

Fasciola hepatica is a helminth parasite with a worldwide distribution, which can cause chronic liver disease, fasciolosis, leading to economic losses in the livestock and public health in many countries. Control is mostly reliant on the use of drugs, and as a result, drug resistance has now emerged. The identification of F. hepatica genes involved in interaction between the parasite and host immune system is utmost important to elucidate the evasion mechanisms of the parasite and develop more effective strategies against fasciolosis. In this study, we aimed to identify molecules in F. hepatica excretory and secretory products (FhESPs) interacting with the host peripheral blood mononuclear cells (PBMCs), Th1-like cytokines (IL2 and IFN-γ), and Th17-like cytokines (IL17) by Co-IP combined with tandem mass spectrometry. The results showed that 14, 16, and 9 proteins in FhESPs could bind with IL2, IL17, and IFN-γ, respectively, which indicated that adult F. hepatica may evade the host immune responses through directly interplaying with cytokines. In addition, nine proteins in FhESPs could adhere to PBMCs. Our findings provided potential targets as immuno-regulators, and will be helpful to elucidate the molecular basis of host-parasite interactions and search for new potential proteins as vaccine and drug target candidates. [ABSTRACT FROM AUTHOR]

Liver flukes (Fasciola spp.) and rumen flukes (Paramphistomum spp.) are significant parasites in livestock worldwide, and Fasciola spp. are considered an important zoonotic parasite. To our knowledge, there are no reports on fluke species identification and epidemiological prevalence in yak and Tibetan sheep around Qinghai Lake, China. Therefore, this study aimed to identify the major fluke species and determine the prevalence of fluke infections among yak and Tibetan sheep in this area. A total of 307 fecal samples were collected and fluke eggs identified using morphology and molecular methods. Our study is the first to display that the predominant fluke species were F. hepatica and P. leydeni in yak and Tibetan sheep around Qinghai Lake. The overall prevalence of fluke infections in yak and Tibetan sheep was 57.7% (177/307). Specifically, the prevalences of F. hepatica and P. leydeni were 15.0% (46/307) and 31.6% (97/307), respectively, and the co-infection of both species was 11.1% (34/307). No significant difference existed in the prevalence of overall fluke infection between yak and Tibetan sheep (p < 0.05). However, F. hepatica prevalence was significantly different in yak and Tibetan sheep (p < 0.05) but not P. leydeni. The findings of this study provide useful information about the current status of natural fluke invasion in yak and Tibetan sheep around Qinghai Lake, which could be important for monitoring and controlling these parasites in the region., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The common liver fluke Fasciola hepatica causes an increasing burden on human and animal health, partly because of the spread of drug-resistant isolates. As a consequence, there is considerable interest in developing new drugs to combat liver fluke infections. A group of potential targets is a family of calcium-binding proteins which combine an N-terminal domain with two EF-hand motifs and a C-terminal domain with predicted similarity to dynein light chains (DLC-like domain). The function of these proteins is unknown, although in several species, they have been localised to the tegument, an important structure at the host-parasite interface. Here, we report the X-ray crystal structure of the DLC-like domain of F. hepatica calcium-binding protein 2 (FhCaBP2), solved using single-wavelength anomalous diffraction and refined at 2.3 Å resolution in two different crystal forms. The FhCaBP2 DLC-like domain has a structure similar to other DLC domains, with an anti-parallel β-sheet packed against an α-helical hairpin. Like other DLC domains, it dimerises through its β-strand, which extends in an arch and forms the fifth strand in an extended β-sheet of the other monomer. The structure provides molecular details of the dimerisation of FhCaBP2, the first example from this family of parasite proteins. [ABSTRACT FROM AUTHOR]

Bimiracidial infections of Lymnaea palustris and Lymnaea stagnalis (shell height at exposure, 4 mm) with Fasciola hepatica were carried out during six successive snail generations to determine if prevalence and intensity of snail infection increased over time through descendants issuing from eggs laid by parents already exposed to this digenean. Controls were constituted by a French population of Galba truncatula (a single generation) infected according to the same protocol. In a first experiment performed with the F1 to F5 generations of L. palustris, the prevalence and intensity of F. hepatica infection in snails progressively increased. Immature rediae and a few cercariae-containing rediae of the digenean were observed in L. stagnalis from the F3 generation, but no free cercaria was noted in the bodies of this lymnaeid from the F4 to F6 generations. In another experiment carried out with the F6 generation of L. palustris, the prevalence of F. hepatica infection and the number of shed cercariae were significantly lower in L. palustris than in G. truncatula. This mode of snail infection suggests an explanation for cases of human fasciolosis occurring in central France after the collection of wild watercress from beds where L. palustris was the sole lymnaeid. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate hepatic and seric levels of purines, as well as their breakdown products in rats infected by Fasciola hepatica on days 15 and 87 post-infection (PI). Rats were divided into two groups: uninfected ( n = 10) and infected ( n = 20). On day 15 ( n = 5 for uninfected group and n = 10 for infected group) and 87 PI ( n = 5 for uninfected group and n = 10 for infected group), animals were euthanized for sampling to evaluate levels of purines by high-performance liquid chromatography. In serum, ATP increased ( P < 0.05) and ADP decreased ( P < 0.05) on days 15 and 87 PI, while AMP increased ( P < 0.05) only on day 15 PI. Hypoxanthine levels increased ( P < 0.05) on days 15 and 87 PI, while adenosine and xanthine levels decreased and increased ( P < 0.05), respectively, on day 87 PI. No difference was observed regarding seric inosine and uric acid ( P > 0.05). Hepatic ATP, adenosine, and uric acid levels decreased ( P < 0.05) on days 15 and 87 PI. AMP levels decreased ( P < 0.05) on day 87 PI, while xanthine levels increased ( P < 0.05) on day 15 PI in the liver. Also in the liver, hypoxanthine levels increased ( P < 0.05) on day 15 PI and decreased ( P < 0.05) on day 87 PI. On the other hand, there was no difference on hepatic ADP and inosine levels ( P > 0.05). Therefore, it is possible to conclude that F. hepatica infection can change purine levels, which may be associated with an inflammatory process, and these alterations may influence fasciolosis pathogenesis. [ABSTRACT FROM AUTHOR]

Fasciolosis, caused by the liver fluke Fasciola hepatica, is a major parasitic disease of livestock that causes significant economic losses worldwide. Although drugs are effective against liver flukes, they do not prevent reinfection, and continuous treatment is costly. Moreover, resistant fluke strains are emerging. In this context, vaccination is a good alternative since it provides a cost-effective long-term prevention strategy to control fasciolosis. In this paper, we evaluate the Fhmuc peptide as a potential vaccine against fasciolosis. This peptide derives from a mucin-like protein highly expressed in the infective stage of Fasciola hepatica. Mucin-like molecules expressed by parasites can contribute to several infection processes by protecting the parasite from host proteases and recognition by the immune system. We show that the Fhmuc peptide induces Th1-like immune responses specific for F. hepatica excretion-secretion products (FhESP) with a high production of IFNγ. We also investigated whether this peptide could protect animals from infection, and present preliminary data indicating that animals treated with Fhmuc exhibited reduced liver damage compared to non-immunised animals and that this protection was associated with a recruitment of B and T lymphocytes in the peritoneum, as well as eosinophils and mature dendritic cells. These results suggest that the mucin-like peptide Fhmuc could constitute a potential vaccine candidate against fasciolosis and pave the way towards the development of vaccines against parasites. [ABSTRACT FROM AUTHOR]

Natural infections of lymnaeid snails by Fasciola hepatica are of primary importance to study transmission. Also, infected snails in the field can be used to explore the existing compatibility in host-parasite interactions. This paper aimed to describe the infection rate of Galba cubensis populations in fasciolosis transmission areas. Eight sites were sampled in western Cuba and 24 infected snails at six sites were found. The mean prevalence was 2.94 % and the maximum value was 11.4 %. The intensity of parasite infection was assessed as the number of rediae inside a single snail. High variation within the sites examined was observed, but a maximum of 76 rediae was recovered from one individual. Although the presence of two other trematode families (Schistosomatidae and Paramphistomatidae) was discovered in dissected individuals, no co-infection with F. hepatica was observed. This is the first time a study of natural prevalence of F. hepatica infection is carried out in Cuba, considered a hyper endemic country for bovine fasciolosis. Our results suggest that fasciolosis transmission may occur even when the number of infected snails remains relatively low. [ABSTRACT FROM AUTHOR]

Juvenile Pseudosuccinea columella, measuring 1 or 2 mm in height, were subjected to single-miracidium infections with Fasciola hepatica to determine the developmental pattern of redial generations and count free and live rediae according to their generation. Controls were constituted of juvenile Galba truncatula infected according to the same protocol. In the four groups, redial counts were performed in snails dissected every week from day 7 to day 49 post-exposure at 20 °C. Most infected snails showed a normal development of redial generations, whatever the lymnaeid species. In P. columella, the total number of live rediae on day 49 was 24.6 and 34.6 per infected snail in the 1 and 2-mm groups, respectively (instead of 11.5 and 18.8 rediae in the corresponding groups of G. truncatula). A single mother redia (R1a) producing only daughter rediae of the second generation was noted in each snail of three groups, while the 2-mm P. columella showed the presence of a single (43 snails/71) or two (28/71) R1a redia(e) within their bodies. The mean number of other mother rediae and that of daughter rediae of the second generation were low in the 1 and 2-mm groups of both lymnaeids. Besides, there was a delay in redial development. The development of two live R1a rediae in several P. columella from the 2-mm group needs to verify if this process would be specific to P. columella or would occur in other lymnaeid species known for their good susceptibility to the digenean and their larger size to allow harbouring rediae. [ABSTRACT FROM AUTHOR]

The aim of the present study was to genetically characterize Fasciola hepatica strains from diverse ecogeographical regions (America and Europe), susceptible and resistant to Triclabendazole, using the random amplified polymorphic DNA fragments (RAPDs-PCR) technique to elucidate genetic variability between the different isolates. Ten different oligonucleotide primers of 10 bases with GC content varying from 50-70 % were used. A polymerase chain reaction (PCR) was carried out in 25 μl of total volume. Duplicate PCR reactions on each individual template DNA were performed to test the reproducibility of the individual DNA bands. The size of the RAPD-PCR fragments was determined by the reciprocal plot between the delay factors (Rf) versus the logarithm of molecular weight ladder. The phenogram obtained showed three main clusters, the major of which contained European Strains (Cullompton and Sligo) showing a genetic distance of 27.2 between them. The American strains (Cedive and Cajamarca) on the other hand formed each their distinctive group but clearly maintaining a closer genetic relationship among them than that to their European counterparts, with which showed a distance of 33.8 and 37.8, respectively. This polymorphism would give this species enhanced adaptability against the host, as well as the environment. The existence of genetically different populations of F. hepatica could allow, against any selection pressure, natural or artificial (for use fasciolicides products and/or control measures), one or more populations of F. hepatica to be able to survive and create resistance or adaptability to such selective pressure. [ABSTRACT FROM AUTHOR]

The control of fasciolosis, as that of other vector-borne diseases, must be related to the control of the lymnaeid snails, the intermediate hosts of the parasite. Thus, an accurate epidemiological surveillance of the transmission foci where the infected mollusks occur is essential. For this purpose, immunoassays could be a useful tool. However, information regarding specific proteins of intramolluscan larvae and previous studies concerning monoclonal antibody generation against asexual stages of trematodes are scarce. Therefore, we explored the antigenic features of intramolluscan rediae of Fasciola hepatica to evaluate three antigenic preparations in order to use the most promising one for developing specific monoclonal antibodies. Mouse antiserum was generated against each antigen for assessing the polyclonal antibody response against the crude extract of rediae and the cross-reactivity against lymnaeids. The specific C-terminal of F. hepatica cytochrome c oxidase subunit I (first antigen), selected by in silico analyses, might not be the appropriate target for immunoassay detection of infected snails, due to its low representation in the total extract of rediae. The majoritarian mixture of low-molecular-weight proteins (<30 kDa) from the rediae homogenate (second antigen) revealed a significant cross-reactivity with lymnaeids. Evidence of the existence of mimetic immunogenic epitopes in this fraction of F. hepatica rediae was achieved. High immunogenicity of the crude extract of rediae (third antigen), mainly related to parasite's specific epitopes, was regarded. Therefore, the rediae homogenate is stated as the most promising antigen from those evaluated, for monoclonal antibody development with potentialities for detecting F. hepatica-infected snails. [ABSTRACT FROM AUTHOR]

Experimental infections of Egyptian Pseudosuccinea columella with one or two miracidia of Fasciola hepatica per snail were carried out to determine the developmental pattern (normal or abnormal) of redial generations and specify the number of free rediae developing in snails according to their generation. Controls were constituted by a French population of Galba truncatula infected according to the same protocol. Most infected P. columella showed a normal development of redial generations (96.2-98.1 vs 75.5-85.7 % for G. truncatula). In each redial category, free rediae were more numerous in P. columella than in G. truncatula, and their number were also greater in the two-miracidia groups than in single-miracidium infections for each lymnaeid considered separately. This increase in redial production was mainly due to the number of first mother (R1a) rediae producing daughter rediae only: 2 per P. columella (vs one redia in G. truncatula) in single-miracidium groups and 3.1 (vs 1.9) in the two-miracidia groups. In P. columella, the mean total number of free rediae developing in single-miracidium and bimiracidial infections was 77.2 and 117.6, respectively (instead of 33.5 and 52.1 rediae in G. truncatula). The number of F. hepatica rediae present in P. columella was related to the number of fully grown sporocysts and the quantity of R1a rediae which developed into the snail body. [ABSTRACT FROM AUTHOR]

In the current study, Fasciola hepatica strains of sheep with different degrees of resistance to anthelmintics were analyzed by sequencing the cytochrome C oxidase (COX1) and the NADH dehydrogenase (NAD1) subunits. The strains were as follows: LS, susceptible to all drugs tested; CS, resistant to albendazole and triclabendazole; and SV, resistant to albendazole and clorsulon. The molecular characterization was done in eggs recovered from sheep infected by LS and CS. In relation to SV, eggs were recovered before (SV0) and after a treatment with albendazole (SVA) and clorsulon (SVC). Nested PCRs were carried out to amplify a fragment of 798 bp of the COX1 subunit and 870 bp of the NAD1 subunit. The pairwise sequence identity between eggs was analyzed for each strain. Population diversity indices, neutrality indices, and the degree of gene flow among the strains were evaluated. As a result, we have shown that there was homogeneity in the demographic expansion of the studied strains, and, according to the pairwise fixation index, these were not genetically differentiated. Although we found that the resistant strains had lower pairwise percentage similarities, higher haplotype diversity, and higher frequencies of specific SNPs, especially in the COX1 subunit, these differences were not very significant. Therefore, we conclude that the presence of adult flukes resistant to anthelmintics does not result in significant higher genetic diversity in the mtDNA of their eggs. [ABSTRACT FROM AUTHOR]

Thirty goats were randomly allocated in five groups of six animals each, for immunization with 1 × 10 phage particles of clones 11, 13, and 13 with Quil A adjuvant and wild-type M13KE phage at the beginning and 4 weeks later. The control group received phosphate-buffered saline. All groups were challenged with 200 metacercariae at week 6 and slaughtered 14 weeks later. The mean worm burdens after challenge were reduced by 46.91 % and 79.53 % in goats vaccinated with clones 13 and 13 with Quil A ( P < 0.05), respectively; no effect was observed in animals immunized with clone 11 and M13KE phage. Animals receiving clones 11, 13, and 13 with Quil A showed a significant reduction in eggs output. Vaccinated animals produced parasite-specific total IgG antibody which were boosted after challenge with metacercariae of F. hepatica. Furthermore, levels of anti-phage total IgG increased rapidly within 2 weeks of the first vaccination and were always significantly higher in all vaccinated goats than in the infected control group. The fluke burden of goats immunized with clones 13 and 13 with Quil A was significantly correlated with IgG2 and total IgG. Goats vaccinated with phage clones produced significantly high titres of IgG1 and IgG2 antibodies indicating a mixed Th1/Th2 response. These data indicate that cathepsin L1 mimotopes has a potential as a vaccine candidate against Fasciola hepatica, whose efficacy will be evaluated in other host species, including those of veterinary importance. [ABSTRACT FROM AUTHOR]

The effects of the lipopolysaccharide (LPS) from Ochrobactrum intermedium was evaluated in sheep experimentally infected with Fasciola hepatica. Animals were divided into four groups: two treated with the LPS (T1/T2) and two controls (C1/C2). T1/C1 were slaughtered at 30 days postinfection (dpi) and T2/C2 at 85 dpi. Body weight and body condition were found higher in T1 and T2 than in controls, although differences were not significant. Treated sheep showed lower cumulative fecal egg count than controls ( p < 0.01). Levels of red blood cells (RBC), white blood cells, hemoglobin, and hematocrit (HCT) were higher in T1 and T2. Significant differences ( p < 0.05) in RBC and HCT were found between groups at 84 dpi. More severe macrocytic and hypochromic anemia was observed in C1 and C2 than in treated groups. Total protein and albumin values were higher in T1 and T2 ( p < 0.01) until 29 dpi. At the end of the trial, no significant differences were observed in hepatic enzymes, although gamma-glutamyl transferase and aspartate aminotransferase values were higher in C2, and alanine aminotransferase was higher in T2. At necropsy, the mean weight of liver, fibrosis in portal triads, and ganglion size were similar in all groups. The number and size of flukes was greater in C2 than in T2 ( p < 0.05). The histological examinations revealed a higher degree of parenchymatous fibrosis in T2 compared to C2 ( p < 0.05). The administration of LPS from O. intermedium increased the nonspecific resistance against F. hepatica in experimentally infected sheep. [ABSTRACT FROM AUTHOR]

Two French populations of Galba truncatula were subjected to experimental infections with Egyptian and French isolates of Fasciola sp. miracidia, originating from cattle and sheep, to compare characteristics of snail infections in allopatric and sympatric groups. All sampled Egyptian isolates were identified as Fasciola hepatica using microsatellite markers. Compared to snails infected with French miracidia, snail survival at day 30 post-exposure was significantly greater in the Egyptian groups, while prevalence of infection was significantly lower (in an Egyptian group infected with cattle-derived miracidia) or did not show any significant differences in the other three cases. The total number of metacercariae was significantly higher in the four Egyptian groups. However, snail population and the mammalian origin of F. hepatica had also a significant effect on this parameter. The dissection of snail cadavers showed a significantly higher number of free rediae in the Egyptian groups, even if snail population also had a significant effect on the redial burden. Both Egyptian isolates of F. hepatica could easily develop in French snails, causing a low mortality in snails and inducing a metacercarial production higher than that noted in sympatric infections. However, the mammalian origin of F. hepatica eggs and the quality of snail populations as intermediate hosts had to be taken into account for studying local adaptation in reason of their effects on this process. [ABSTRACT FROM AUTHOR]

Allopatric infections of French Galba truncatula with an Argentinean isolate of Fasciola hepatica were carried out to determine the infectivity of foreign miracidia in three snail populations differing by their susceptibility to French miracidia (two highly and one poorly susceptible populations). Sympatric infections of G. truncatula with French miracidia were used as controls. Compared to sympatric infections of G. truncatula, snail survival at day 30 post-infection in allopatric groups was significantly lower in a highly susceptible population and significantly greater in the other two. Prevalence in snails infected with the allopatric isolate was significantly lower (16.4-34.5 % instead of 58.6-72.1 %), whereas their patent period was significantly longer (a mean of 69.9-85.9 days instead of 6.4-20.7 days). The mean number of metacercariae was also higher in allopatric groups (236.5-897.3 per cercariae-shedding snail instead of 70.7-222.1). Owing to longer patent periods, the Argentinean isolate of F. hepatica was less pathogenic for these snails. The lower prevalence of infection, the longer patent period and the higher number of metacercariae noted in allopatric groups might be the consequence of an adaptive mechanism used by this digenean introduced to the New World to infect new populations of unusual intermediate hosts. [ABSTRACT FROM AUTHOR]