The Role of Dicrocoelium dendriticum Egg Antigen in Colitis: A Molecular, Pathological and Serological Study in an Experimental Model of C57BL/6 Mice.

BACKGROUND: Inflammatory bowel disease (IBD) is a chronic and recurrent disease of the gastrointestinal tract that enhances the chance of developing colorectal cancer. Since standard treatments such as Mesalazine have limited effectiveness and are often accompanied by numerous side effects, the use of immune modulators derived from worms has been proposed as a new immunotherapy method for inflammatory diseases such as ulcerative colitis. The aim of this study is to investigate the protective effects of D. dendriticum egg antigen on DSS-induced colitis in C57BL/6 mice. METHODS: D. dendriticum egg antigen was extracted and DSS (3.5%) was used to induce colitis in mice. Treatment and prophylaxis included intraperitoneal injections of D. dendriticum egg antigen. Histopathological indicators and the disease activity index (DAI), including weight loss, rectal bleeding, stool consistency, and rectal prolapse, were used to assess the severity of colitis. Real-time PCR measured the expression of transforming growth factor-ß (TGF-ß) and interleukin-17 (IL-17), while ELISA determined the concentration of these cytokines. RESULTS: Treatment with D. dendriticum egg antigen significantly improved the clinical symptoms and decreased the severity of DSS-induced colitis. Furthermore, D. dendriticum egg antigen increased the expression of TGF-ß mRNA and reduced the expression of IL-17 mRNA, leading to a positive adjustment in the regulation of proteins and reduction of inflammatory proteins. As a result, the macroscopic, microscopic inflammation and activity index (DAI) of DSS-induced decreased. CONCLUSION: D. dendriticum egg antigen provides a promising new way to modulate the immune system and improve ulcerative colitis.

Immunomodulatory effect of Dicrocoelium dendriticum ova on DSS-induced experimental colitis in C57BL/6 mouse.

Inflammatory bowel disease (IBD) significantly diminishes an individual's quality of life and increases the risk of colorectal cancer. Recent clinical and experimental findings suggest that infection with parasitic helminths may suppress the development of certain inflammatory conditions. The objective of this study was to evaluate the immunoregulatory effects of Dicrocoelium eggs on experimentally induced colitis in C57BL/6 mice using dextran sulfate sodium (DSS). C57BL/6 mice received 3.5% DSS orally for 7 days to induce colitis, during which they were treated intraperitoneally with Dicrocoelium eggs. The severity of colitis was assessed through parameters such as body weight, stool consistency or bleeding, disease activity index (DAI), colon lengths, macroscopic scores, histopathological findings, colon gene expression levels, and serum cytokine levels. Our results indicated that Dicrocoelium eggs administration significantly reduced the severity of colitis and disease activity. Histopathological scores improved, correlating with downregulation of IFN-γ and upregulation of IL-4 expression. This findings suggest the therapeutic potential of Dicrocoelium eggs in treating colitis. Immunotherapy involving Dicrocoelium eggs primarily induces a Th2 response and modulates IFN-γ, contributing to reduced inflammation in colitis. Thus, this approach could be a promising therapeutic strategy for alleviating inflammation in IBD.

Lack of Efficacy of Albendazole against Dicrocoelium dendriticum Infection in a Sheep Farm in France.

Dicrocoeliosis is a common parasitic disease in European sheep farming. The prevalence of infection by this parasite can reach almost 70% in areas where the environment is favorable to intermediate hosts. In France, only one drug is currently available for the treatment of dicrocoeliosis: albendazole at a dose of 15 mg/kg in a single administration. However, a control coproscopy following a routine treatment led us to suspect that the efficacy of albendazole against Dicrocoelium dendriticum had diminished. Therefore, we carried out an efficacy test on 15 animals by treating them with albendazole at a dose of 15 mg/kg and performing a coproscopy on D0 and a control coproscopy 14 days later. We obtained a 39% reduction in the excretion of D. dendriticum eggs. This shows a reduction in the expected efficacy of albendazole, which is normally more than 90% in other studies involving this molecule at a dosage of 15 mg/kg. These results are of major concern as albendazole is currently the only drug available in France to treat dicrocoeliosis.

Dicrocoeliidae Family: Major Species Causing Veterinary Diseases.

This chapter analyses the taxonomic position of the Dicrocoeliidae family and several of its genera and species. The chapter reviews the biology of major veterinary disease-causing species, including Dicrocoelium dendriticum, Dicrocoelium hospes, Dicrocoelium chinensis, Eurytrema pancreaticum and Platynosomum fastosum. All these species have indirect life cycles with two intermediate hosts: molluscs as the first host and ants, grasshoppers and lizards as the second host. Dicrocoelium dendriticum is a widespread liver fluke found in ruminants across Europe, Asia, North Africa and North America. It can also infect humans. Dicrocoelium hospes is widely distributed in the savanna areas of Africa south of the Sahara, while D. chinensis is mainly found in ruminants in East Asia and some European countries (probably imported from Asia). Eurytrema pancreaticum is a common parasite that lives in the bile ducts, gall bladder, pancreatic ducts and intestines of ruminants. It is found in Europe, Madagascar, Asia and South America. Adults of P. fastosum live in the liver, gall bladder and pancreas of birds and mammals in Europe, Africa, Asia, North, Central and South America. Information on the epidemiology, pathology, clinical aspects, diagnosis, treatment, control, prevention and economic impact of Dicrocoeliosis caused by D. dendriticum, Eurytrematodosis and Platynosomiosis have been included.

Ovine dicrocoeliosis in Castellón province, eastern Spain: Prevalence, dynamics, and comparative study of different diagnostic techniques.

Dicrocoeliosis is a parasitic disease that mainly affects ruminants during grazing, caused by trematodes of the genus Dicrocoelium, with D. dendriticum being the most common species worldwide. This parasitosis is a chronic and generally subclinical process, with nonspecific signs, which makes its diagnosis challenging. This study aimed to determine the prevalence and seasonal dynamics of D. dendriticum infection in adult sheep from the Valencian Community, eastern Spain, as well as to evaluate the efficacy of flotation and sedimentation techniques when compared with the macroscopic exam of the liver. From February to May 2018, 2019, 2020, 2021, and 2022, a total of 290 adult sheep were examined. The animals were sourced from Castellón province, where a semi-intensive production system predominates. Each animal was euthanized and underwent a macroscopic examination of the liver, as well as a fecal analysis. Among the sampled animals, 117 (40.6%) tested positive for adult trematodes in their liver, while 87 (30%) showed evidence of trematode eggs in the coprological exam, reaching a total of 126 sheep parasitized, with a prevalence of 43.4%. The parasitic burden was established in 90.3 adults per animal when the liver was examined and in 54.5 eggs per gram when the sedimentation coprological exam was performed. No eggs were observed when the flotation technique was employed. A positive correlation was found between the number of adults in the liver and the fecal egg count. No significant differences were detected in the prevalence or parasitic burden throughout the study. Considering the difficulty in controlling the intermediate hosts and the complexity of the life cycle, effective diagnostic methods, combined with the adoption of other preventive measures, is crucial to achieving proper management of this parasitic disease.

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.

Efficacy of a single-dose albendazole against lancet liver fluke Dicrocoelium dendriticum and liver enzymes activity in naturally infected sheep.

Infections with D. dendriticum are distributed worldwide and mostly associated with ruminant livestock. Depending on the length and strength of the infection it can be manifested with losses in milk production, reductions in milk and wool quality, decreased weight gains, reproductive performance and poor carcass quality. The objective of this study was to determine the efficacy of albendazole (ABZ) against the lancet liver fluke Dicrocoelium dendriticum in naturally infected sheep using parasitological methods. Twenty-four sheep were divided into four groups: two untreated control groups (C1, C2) and two treated groups (T1, T2), with six animals in each group. The sheep in the treated groups were administered a single oral dose (15 mg/kg bwt) of ABZ suspension. After ABZ treatment the animals were slaughtered on Day 14 (groups C1, T1) and Day 30 (groups C2, T2) and were necropsied. Coprological therapeutic ABZ efficacy reached 92.4% on Day 14 (P < 0.001) and 88.5% on Day 30 (P < 0.001). On Day 30, the serum activities of hepatic and cholestatic enzymes including serological analysis of total protein concentration (TP) and protein fractions were evaluated. Significant decrease of aspartate aminotransferase (AST) (P < 0.01) and gamma-glutamyltransferase (GGT) (P < 0.05) activity by 36.9% and 34.6%, respectively, were detected for sheep in T2 group. These enzymes showed a strong positive correlation to fluke burden: AST (r = 0.654) and GGT (r = 0.768), respectively (P < 0.05). Additionally, the electrophoretic analysis of serum total protein and protein fraction concentrations revealed minimal hypoproteinemia and hyperalbuminemia after ABZ treatment. The decrease of liver enzyme activities and their correlation with fluke burden may indicate recovery of hepatocellular and biliary damage following the reduction of fluke burdens after ABZ therapy. A decline in AST and GGT activity could serve as a valuable adjunct bioindicator of liver damage and fluke reduction after treatment of dicrocoeliosis in naturally infected sheep.

Expression of trematode-induced zombie-ant behavior is strongly associated with temperature.

Parasite-induced modification of host behavior increasing transmission to a next host is a common phenomenon. However, field-based studies are rare, and the role of environmental factors in eliciting host behavioral modification is often not considered. We examined the effects of temperature, relative humidity (RH), time of day, date, and an irradiation proxy on behavioral modification of the ant Formica polyctena (Förster, 1850) by the brain-encysting lancet liver fluke Dicrocoelium dendriticum (Rudolphi, 1819). This fluke induces ants to climb and bite to vegetation by the mandibles in a state of temporary tetany. A total of 1264 individual ants expressing the modified behavior were observed over 13 non-consecutive days during one year in the Bidstrup Forests, Denmark. A sub-set of those ants (N = 172) was individually marked to track the attachment and release of infected ants in relation to variation in temperature. Infected ants primarily attached to vegetation early and late in the day, corresponding to low temperature and high RH, presumably coinciding with the grazing activity of potential herbivorous definitive hosts. Temperature was the single most important determinant for the induced phenotypic change. On warm days, infected ants altered between the manipulated and non-manipulated state multiple times, while on cool days, many infected ants remained attached to the vegetation all day. Our results suggest that the temperature sensitivity of the infected ants serves the dual purpose of exposing infected ants to the next host at an opportune time, while protecting them from exposure to high temperatures, which might increase host (and parasite) mortality.

Case report: Infection with Dicrocoelium dendriticum in a Japanese Chin dog.

Dicrocoelium dendriticum is a trematode colonising the bile ducts of herbivores. Coproscopic findings in dogs are usually considered gastrointestinal passages of eggs after ingestion of unheated liver tissue or infected ruminant faeces. Here, a Japanese Chin presented with diarrhoea and weight loss. Eggs comparable to D. dendriticum were detected in faeces and infection was confirmed via PCR and by ruling out differential diagnoses. Egg excretion continued for a period of 10 months. Praziquantel (50 mg/kg body weight [BW]) was administered orally for four consecutive days. Egg excretion 10 days after treatment entailed further treatments with 100 mg/kg BW, again for four days. Faecal samples were negative ten days and four weeks afterwards, diarrhoea resolved, and the dog gained weight. In cases of repeated coproscopic positivity for D. dendriticum, an infection with dogs acting as definitive hosts should be considered. Treatment with praziquantel at a higher dosage may be required.

A Bibliometric Analysis on Dicrocoelium dendriticum.

Background: Dicrocoelium dendriticum, a worldwide zoonotic trematode, is a common parasite of ruminant animals, but humans can be the definitive host by chance. We analyzed the world situation of the parasite from the perspective of the One Health concept by analyzing the research literature published from 1931 to 2022. Methods: Published documents related to D. dendriticum were searched from the Scopus database. Focusing on a visual analysis of the main research documents on D. dendriticum, Dimensions free web app was used to conduct co-occurrence analysis with keywords, countries, institutions, and authors. Moreover, key clustering research, affiliaitons, journals, countries, and authors were determined. Results: The Higher Council for Scientific Research (CSIC) was the most publishing affiliation on D. dendriticum with 19 articles. While the Veterinary Parasitology Journal was the mostly publishing journal on D. dendriticum with 38 articles, the most productive country was Iran. The authors Giuseppe Cringoli and Laura Rinaldi from Università degli Studi di Napoli Federico II, Naples, Italy were the mostly publishing authors. Conclusion: This bibliometric analysis provides an overall description of the current state of D. dendriticum research and the initial exploration of future research directions. Our analysis provides guidance for the development of research on D. dendriticum.

Rapid Detection and Identification of Fasciola spp. and Dicrocoelium spp. Isolated from the Ruminant Livestock of Northwest Iran Using High-Resolution Melting Analysis (HRM).

Background: The liver flukes of the Fasciola species and Dicrocoelium spp. are recognised as parasites of domestic and wild herbivores. Both species of F. hepatica and F. gigantica as well as D. dendriticum are distributed in Iran. The present study aimed to identify Fasciola spp. and Dicrocoelium spp. using mitochondrial Cox1 (cytochrome c oxidase I) gene by HRM method. Methods: Totally, thirty infected liver specimens were collected from the sheep (n:23) and cattle (n:7) at the abattoirs of Qazvin Province, northwest Iran in 2022. DNA extraction and PCR amplification of Cox1 gene were conducted by HRM technique. DnaSP v.5.0 was used for compression of diversity indices of ribosomal 28S rDNA and mitochondrial Cox1 markers of Dicrocoelium spp. The taxonomic status of Dicrocoelium spp. was performed by sequencing and phylogenetic analysis. Results: Overall, 26 and 4 isolates were identified as F. hepatica and F. gigantica, respectively. D. dendriticum was the sole infecting species of Dicrocoelium revealed by HRM analysis. Genomic analysis showed a moderate (28S rDNA genes: 0.600±0.215) to high (Cox1: 0.733±0.155) haplotype diversity for D. dendriticum. Conclusion: The parasite-dependent mitochondrial gene (Cox1) could identify a higher genetic diversity of D. dendriticum compared to nuclear 28S rDNA gene. HRM technique in the present study found to be a reliable technique for identification and genetic diversity of liver flukes but more comprehensive and in-depth studies in different parts of the country are needed.

Dairy goats helminthosis and its potential predictors in Greece: Findings from an extensive countrywide study.

The objectives of the present study were: (a) to describe the prevalence of helminth infections from pooled faecal samples from goat herds across Greece, (b) to evaluate herd-related factors potentially associated with the presence of these infections in the herds and (c) to compare the findings to those of a previous relevant study performed in sheep flocks. A cross-sectional study was carried out in 119 goat herds around Greece. Helminths were recovered from samples from 93.3% of herds: Dicrocoelium dendriticum (from 15.1% of herds), Paramphistomum cervi (from 0.8% of herds), Moniezia spp. (from 25.2% of herds), Trichostrongylidae (from 89.1% of herds), Nematodirus spp. (from 16.8% of herds), Strongyloides papillosus (from 5.0% of herds), Trichuris spp. (from 18.5% of herds) and lungworms (from 23.5% of herds). Mean epg counts in all herds in the study were 219 epg. In multivariable analyses, for 'high (> 300) epg counts in faecal samples' the age of kid removal from their dams (p = 0.045) was found to be a significant factor, for 'high proportion (> 64%) of Teladorsagia spp. in faecal samples' the month of the start of the kidding season (p = 0.045) was a significant factor, for 'high proportion (> 27%) of Haemonchus contortus in faecal samples' nutritional modifications during gestation (p = 0.002) and application of reproductive control practices in the farm (p = 0.013) were the significant factors and for 'presence of D. dendriticum in faecal samples' the number of veterinary visits to the farm annually (p = 0.040) was found to be significant.

Extracellular vesicles from the trematodes Fasciola hepatica and Dicrocoelium dendriticum trigger different responses in human THP-1 macrophages.

Extracellular vesicles (EVs) released by the helminths Dicrocoelium dendriticum and Fasciola hepatica are important modulators of the host immune response, contributing to the establishment of the infection. Monocytes and, in particular, macrophages are major regulators of the inflammatory response and are likely responsible for the phagocytosis of most of the parasite EVs. In this study, we isolated EVs from F. hepatica (FhEVs) and D. dendriticum (DdEVs) by size exclusion chromatography (SEC) and characterized them by nanoparticle tracking analysis, transmission electron microscopy and LC-MS/MS, and analyzed the cohort of proteins. The treatment of monocytes/macrophages with FhEVs, DdEVs or EV-depleted fractions from SEC, demonstrated species-specific effects of the EVs. In particular, FhEVs reduce the migratory capacity of monocytes and the analysis of the cytokine profile showed that they induce a mixed M1/M2 response, exerting anti-inflammatory properties in Lipopolysaccharide-activated macrophages. In contrast, DdEVs do not affect monocyte migration and seem to have pro-inflammatory properties. These results correlate with the differences in the life cycle of both parasites, suggesting different host immune responses. Only F. hepatica migrates to the bile duct through the liver parenchyma, driving the host immune response to heal deep erosions. Furthermore, the proteomic analysis of the macrophages upon FhEV treatment identified several proteins that might be involved in FhEV-macrophage interactions.

Helminth Infections in Dairy Sheep Found in an Extensive Countrywide Study in Greece and Potential Predictors for Their Presence in Faecal Samples.

The aims of the present study were: (a) to describe the prevalence of helminth infections from pooled faecal samples from sheep flocks across Greece and (b) to evaluate flock-related factors potentially associated with the presence of these infections in the flocks. An extensive countrywide study was performed on 325 sheep farms throughout Greece; faecal samples were collected from ewes and processed for the identification of helminth parasites. Helminths were detected in samples from 92.9% of flocks; these included Dicrocoelium dendriticum (16.7% of flocks), Fasciola hepatica (0.6%), Paramphistomum cervi (2.2%), Moniezia spp. (18.8%), Trichostrongylidae (85.5%), Nematodirus spp. (18.8%), Strongyloides papillosus (7.1%), Trichuris spp. (20.0%) and lungworms (17.8%). Mean Trichostrongylidae counts across all flocks in the study were 215 epg. Specifically, for Trichostrongylidae, there were differences between flocks that had or had not received anthelmintics during the two months prior to sampling, as well as between flocks located in various areas of the country. In multivariable analyses, for the outcome 'high (>300) epg counts in faecal samples', the month into the lactation period at sampling and the application of reproductive control practices on the farm emerged as significant factors; for the outcome 'high proportion (>63%) of Teladorsagia spp. in faecal samples', the availability of straw bedding emerged as a significant factor; and for the outcome 'high proportion (>63%) of Haemonchus contortus in faecal samples', the age of the farmer emerged as a significant factor. For the outcome 'presence of Trichuris spp. in faecal samples', the provision of finished feed (concentrate) to animals emerged as a significant factor, whilst, finally, for the outcomes 'presence of D. dendriticum in faecal samples' and 'presence of lungworms in faecal samples,' no significant factors emerged.

TREMATODE CLONE ABUNDANCE DISTRIBUTIONS: AN ECO-EVOLUTIONARY LINK BETWEEN PARASITE TRANSMISSION AND PARASITE MATING SYSTEMS.

Most trematodes and some cestodes have obligate life history features that include an asexual developmental stage that can produce genetically-identical individuals (clonemates) followed by an adult stage with sexual reproduction. These life history features can influence the evolutionary mechanism of inbreeding in parasites, especially among self-compatible hermaphroditic endoparasites whose mating opportunities are restricted to within hosts. As clonemate mating in hermaphroditic species produces a genetic inbreeding signature identical to that of self-mating, it is important to understand how clonemates are transmitted through their life stages. A handful of prior studies compared clone richness (number of clones) across life cycle stages to infer transmission processes and to characterize clone abundance distributions (CADs) among hosts. Here we illustrate the use of the proportion of clonemate dyads (PC) within hosts to describe the CADs. PC has several advantages as an ecological metric in that it is unbiased by sample size, takes into account relative parasite burdens, and has a direct transmission interpretation, i.e., the probability of cotransmitting clonemates. Moreover, PC is also an evolutionary metric as it can be used to estimate a potential clonemate mating rate. We demonstrate the use of PC in comparing CADs within and across 2 trematode developmental stages in the lancet fluke Dicrocoelium dendriticum. Also, we show how genetic estimates of apparent selfing (true selfing plus clonemate mating) at larval and juvenile stages can be compared to PC estimated at the adult stage to assess the contribution of clonemate mating to apparent selfing. The eco-evolutionary links presented are generalizable to assess sibling cotransmission as well. Thus, the framework presented herein will facilitate future field-based studies on the transmission and mating systems of parasitic flatworms.

Evaluation of the immunoregulatory effect of Dicrocoelium dendriticum eggs on inflammatory and anti-inflammatory cytokines in EAE model.

Experimental autoimmune encephalomyelitis (EAE) is an appropriate model for the study of the immunologic and pathologic mechanisms in multiple sclerosis (MS). According to the hygiene hypothesis, helminths can improve immunoregulation and have therapeutic effects on immune-mediated diseases. In this study, we used Dicrocoelium dendriticum (Dicrocoeliidae, Platyhelminthes) eggs for the evaluation of their prophylactic and treatment effects on EAE disease. D. dendriticum eggs were extracted. Female C57BL/6 mice were immunized with the specific antigen MOG35-55 , and then the egg extracts were utilized for prophylaxis and/or treatment. Clinical symptoms and other relevant parameters were assessed daily. The mRNA expression of transforming growth factor-ß (TGF-ß), interleukin-10 (IL-10), IL-6, IL-23 and IL-17 were assessed with a real-time polymerase chain reaction technique. Furthermore, secretion of TGF-ß and IL-17 cytokines were determined by enzyme-linked immunosorbent assay. Data indicated that clinical symptoms in prophylaxis and treatment groups were decreased significantly in comparison with the untreated control group (p < .001). Our results showed a significant decrease in IL-17, as well as an increase in TGF-ß cytokine in the treatment group compared to the EAE control group (p < .01). Furthermore, in the prophylaxis and treatment groups, the mRNA expression of disease-associated cytokines decreased and the mRNA expression of the anti-inflammatory cytokines increased. In this study, the D. dendriticum egg ameliorates the clinical symptoms of the EAE model through the modulation of related cytokines of Th17 and Treg cells. Therefore, using this parasite egg could be a new treatment for MS.

Molecular analysis of internal transcribed spacer 2 of Dicrocoelium dendriticum isolated from cattle, sheep, and goat in Iran.

BACKGROUND: Dicrocoelium dendriticum is a broadly distributed zoonotic helminth, which is mainly reported from domesticated and wild ruminants. There is little data covering the molecular features of this trematode; therefore, current study aimed to molecularly analyze D. dendriticum in livestock. METHODS: Totally, 23 samples of D. dendriticum were collected from cattle, sheep, and goat from Ilam, Lorestan, and Khuzestan, three west and south-west provinces of Iran from February to August 2018. After genomic DNA extraction, the internal transcribed spacer (ITS) 2 fragment was amplified and sequenced in samples. To investigate genetic variations through the ITS 2 fragment of obtained D. dendriticum, phylogenetic tree and network analysis were employed. RESULTS: All 23 samples were successfully amplified and sequenced. Phylogenetic tree showed that our samples were clearly grouped in a clade together with reference sequences. There was no grouping based on either geographical regions or hosts. Network analysis confirmed the phylogenetic findings and showed the presence of nine distinct haplotypes, while our samples together most of sequences, which were previously submitted to the GenBank, were grouped in the Hap1. CONCLUSIONS: Our findings indicated that although ITS 2 fragment discriminate D. dendriticum, this fragment is not suitable to study intra-species genetic variations. Therefore, exploring and describing new genetic markers could be more appropriate to provide new data about the genetic distribution of this trematode.

Rumen and Liver Fluke Infections in Sheep and Goats in Northern and Southern Germany.

Paramphistomidosis has recently been identified as an emerging parasitosis in Europe. This study estimated the prevalence of rumen flukes, Fasciola hepatica and Dicrocoelium dendriticum, in small ruminants in Germany and identified occurring rumen fluke species and potential predictors for fluke infections. Pooled fecal samples from 223 sheep farms and 143 goat farms in northern and southern Germany were examined by the sedimentation technique, and molecular species identification was performed on rumen-fluke-positive samples. In sheep, a flock prevalence of 2.2% was detected for rumen flukes. Calicophoron daubneyi was identified on four of five positive farms, while species identification failed in one flock. No rumen fluke eggs were detected in the examined goat herds. F. hepatica eggs were detected in 2.7% of the sheep flocks, while the herd prevalence was 5.6% in goats. Higher prevalence values of 21.1% (sheep) and 7.0% (goats) were observed for D. dendriticum. Mixed grazing with other ruminants and previously identified infections with rumen flukes and/or F. hepatica were identified as predictors for paramphistomidosis. The distribution of the three trematode species followed a geographical pattern associated with conditions favoring the relevant intermediate hosts. C. daubneyi is an established parasite in German sheep at a currently low prevalence.

Survey of Dicrocoelium dendriticum infection in imported Romani and local sheep (Ovis aries), and potential epidemiological role in Saudi Arabia.

The epidemiology of parasite infection in local and imported breeds is quite an essential topic in the meat industry and human health. This study aims to determine the prevalence of Dicrocoelium dendriticum in local sheep breeds (Naemi, Najdi, and Harri) and imported breeds from Romania (Romani breed) and the epidemiology of the infection in Saudi Arabia. Morphological description, the relationship between dicrocoeliasis and sex, age, and histological changes were also presented. A total of 6845 slaughtered sheep at Riyadh Automated slaughterhouse were investigated and followed up for 4 months between 2020-2021. It included 4,680 local breeds and 2,165 imported Romanian breeds. Fecal samples and livers and gallbladders from slaughtered animals were examined for apparent pathological lesions. The results indicated that the infection rate in slaughtered animals was 10.6% in imported Romani sheep and 0.9% in the local Naeimi breed. After identifying the parasite morphologically, negative results were obtained from examining feces, gallbladders, and livers of Najdi and Harry sheep breeds. The mean number of eggs per 20 µL/gallbladder was low (72.78 ± 17.8: 76.11 ± 5.07), medium (334.59 ± 90.6: 292.91 ± 26.63), and high (1113.2 ± 22.3: 1004 ± 143.4) in imported and Naeime sheep, respectively. Significant differences were found between gender and age (males and females were 3.67% and 6.31%; > 2 years 4.39%, 1-2 years 4.22%, and 1 year 3.53%) respectively. Histopathological lesions in the liver were more pronounced. Our survey confirmed the presence of D. dendriticum in imported Romani and local Naeimi sheep, and the potential role of imported sheep in the epidemiology of dicrocoeliasis in Saudi Arabia.

Evaluation of bioaccumulation of some heavy metals in liver flukes (Fasciola hepatica and Dicrocoelium dendriticum) and liver samples of sheep.

Different living organisms are used as applicable bioindicators to determine heavy metal pollutions. Recent studies have shown that helminths parasites can be used as efficient environmental sentinels. This study aimed to evaluate Fasciola hepatica and Dicrocoelium dendriticum as bioaccumulators of lead (Pb), chromium (Cr), cadmium (Cd), copper (Cu). For this work. A total of 50 samples (F. hepatica, D. dendriticum, and livers from the infected and uninfected sheep, each of 10 samples) were collected from sheep slaughtered in Tabriz abattoir. One gram of each sample was incinerated and analyzed by Flame Atomic Absorption Spectrometry. The analysis of samples showed that Pb, Cr and Cu values in F. hepatica were higher than those in D. dendriticum, but only the differences of Pb and Cu were significant. The values of heavy metals in F. hepatica were significantly higher than those in the infected livers (except for Cd), while in D. dendriticum, Cr and Cd were only higher. Based on metal levels in livers, it was found that bioconcentration factors (BCFs) of Cr, Pb and Cu for F. hepatica were much more than one, and BCFs of these three metals between two flukes were statistically significant. This study indicated that F. hepatica had a higher bioindicator potential than D. dendriticum to evaluate environmental pollutants by some metals.