Validation of deep amplicon sequencing of Dicrocoelium in small ruminants from Northern regions of Pakistan.

Dicrocoelium lancet flukes cause significant production loss in ruminant livestock. Although co-infection with multiple Dicrocoelium species within a host is common, techniques for studying the composition of these complex parasite communities are lacking. The pathogenicity, epidemiology, and therapeutic susceptibility of different helminth species vary, and little is known about the interactions that take place between co-infecting species and their hosts. Here, we describe the first applicationof metabarcoding deep amplicon sequencing method to studythe Dicrocoelium species in sheep and goats. First, rDNA ITS-2 sequences of four Dicrocoelium species (Dicrocoelium dendriticum, Dicrocoelium hospes, Dicrocoelium orientalis, and Dicrocoelium chinensis) were extracted from the NCBI public database. Phylogenetic analysis revealed separate clades of Dicrocoelium species; hence, molecular differentiation between each species is possible in co-infections. Second, 202 flukes belonging to seventeen host populations (morphologically verified as belonging to the Dicrocoelium genus) were evaluated to determine the deep amplicon sequencing read threshold of an individual fluke for each of the four species. The accuracy of the method in proportional quantification of samples collected from single hosts was further assessed. Overall, 198 (98.01%) flukes were confirmed as D. dendriticum and 1.98% produced no reads. The comparison of genetic distances between rDNA ITS-2 revealed 86% to 98% identity between the Dicrocoelium species. Phylogenetic analysis demonstrated a distinct clustering of species, apart from D. orientalis and D. chinensis, which sit very close to each other in a single large clade whereas D. hospes and D. dendriticum are separated into their own clade. In conclusion each sample was identified as D. dendriticum based on the proportion of MiSeq reads and validated the presence of this group of parasites in the Gilgit Baltistan and Khyber Pakhtunkhwa provinces of Pakistan. The metabarcoding deep amplicon sequencing technology and bioinformatics pathway have several potential applications, including species interactions during co-infections, identifying the host and geographical distribution of Dicrocoelium in livestock, drug therapy response evaluation and understanding of the emergence and spread of drug resistance.

Parasitic causes of meat and organs in cattle at four slaughterhouses in Sistan-Baluchestan Province, Southeastern Iran between 2008 and 2016.

This 8-year (from 2008 to 2016) retrospective study calculated the percentage of carcass and organ (lung and liver) condemnations and estimated the direct financial costs at four slaughterhouses in Sistan-Baluchestan Province, Southeastern Iran. Each carcass and organ (lung and liver) was thoroughly examined through inspection, palpation and incision following the standard protocol. Identification of the parasites was performed macroscopically. The total direct economic loss due to meat's condemnation was estimated by adding weights of each organ or carcass part and multiplying individual organ totals by their 2016 market unit price. A total of 857,039 cattle were slaughtered during this period, 64,497 livers (7.5%), 31,401 lungs (3.6%) and the carcasses of 1,171 cattle (0.1%) were condemned due to lesions caused by parasites. The main parasitic lesions in the condemned livers were attributed to Echinococcus granulosus (4.2%), Fasciola spp. (3.1%) and Dicrocoelium dendriticum (0.1%). All the condemned lungs were due to E. granulosus (3.6%). Taenia saginata cysticerci were detected in 0.1% of inspected animals. Liver condemnation due to cystic echinococcosis was the highest in fall (4.7%, p < 0.001); while lung condemnation was the highest during spring (3.98%, p < 0.001). Liver condemnation due to Fasciola spp. was the lowest in winter (2.99%, p < 0.001). Carcass condemnation as a result of cysticercosis was the highest in summer (p < 0.001). Considering the 2016 market prices, condemnations due to the studied parasites caused direct costs estimated U.S. $ 3,191,879. To the best of our knowledge, this is the first report estimating the monetary losses due to parasitic infections in the slaughterhouses of this province. Due to the high financial impact of the studied parasites, a control programme should be implemented to decrease this impact.

Gastrointestinal parasite burden in 4th-5th c. CE Florence highlighted by microscopy and paleogenetics.

The study of ancient parasites, named paleoparasitology, traditionally focused on microscopic eggs disseminated in past environments and archaeological structures by humans and other animals infested by gastrointestinal parasites. Since the development of paleogenetics in the early 1980s, few paleoparasitological studies have been based on the ancient DNA (aDNA) of parasites, although such studies have clearly proven their utility and reliability. In this paper, we describe our integrative approach for the paleoparasitological study of an ancient population from Florence in Italy, dated to the 4th-5th c. CE. The first stage consisted in the study of sediment samples from the pelvic area of 18 individuals under light microscopy. This allowed us to detect Ascarid-type eggs belonging very probably to the human-infesting roundworm Ascaris lumbricoides. Ten subsamples were selected corresponding to five individuals, and we extracted their whole DNA following sediment aDNA protocols. A targeted approach allowed us to detect two nematodes and one trematode aDNA fragments, namely Ascaris sp., Trichuris trichiura, and Dicrocoelium dendriticum. Among the five individuals tested for microscopic eggs and aDNA, three of them showed the remains of eggs (only Ascarid-type), but all of them tested positive to the presence of at least one parasite aDNA. Microscopic diagnosis first guided our research for the selection of promising samples while the targeted aDNA approach significantly improved our knowledge in terms of parasitic diversity and frequency in this population subgroup. These results enabled us to discuss the possible impact of latent parasitism in this past population at the time of an epidemic, as suggested in Florence. In particular, the singular case of D. dendriticum detection is discussed in light of the present-day scarcity of genuine human infections. Nevertheless, actual infections are known in the paleoparasitological record, and food habits may have led to false parasitism in this historical context. aDNA leaching from overlying strata may also explain this detection. This study strongly pleads for a systematic integrative approach combining microscopy and aDNA in paleoparasitology.

Molecular confirmation of Dicrocoelium dendriticum in the Himalayan ranges of Pakistan.

Lancet liver flukes of the genus Dicrocoelium (Trematoda: Digenea) are recognised parasites of domestic and wild herbivores. The aim of the present study was to confirm the species identity of Dicrocoeliid flukes collected from the Chitral valley in the Himalayan ranges of Pakistan. The morphology of 48 flukes belonging to eight host populations was examined; but overlapping traits prevented accurate species designation. Phylogenetic comparison of published D. dendriticum ribosomal cistron DNA, and cytochrome oxidase-1 (COX-1) mitochondrial DNA sequences with those from D. chinensis was performed to assess within and between species variation and re-affirm the use of species-specific single nucleotide polymorphism markers. PCR and sequencing of 34 corresponding fragments of ribosomal DNA and 14 corresponding fragments of mitochondrial DNA from the Chitral valley flukes, revealed 10 and 4 unique haplotypes, respectively. These confirmed for the first time the molecular species identity of Pakistani lancet liver flukes as D. dendriticum. This work provides a preliminary illustration of a phylogenetic approach that could be developed to study the ecology, biological diversity, and epidemiology of Dicrocoeliid lancet flukes when they are identified in new settings.

Prevalence of Liver Trematode Infections in Cattle in the Province of Agri in Turkey

Objective: This study was conducted to determine the prevalence of distomatosis in cattle in the Agri province in Turkey. Methods: The livers and bile ducts of 200 slaughtered cattle were examined macroscopically, and the gall bladders were examined by sedimentation. The presence of Fasciola hepatica eggs and antigens in 188 cattle were investigated using sedimentation and coproantigen ELISA, respectively. Egg counts per gram of faeces (EPG) was determined using the modified McMaster sedimentation method. Results: Adult Fasciola hepatica and Dicrocoelium dendriticum were found in the bile ducts of 47 and 25 cattle, respectively. Examination of the gall bladders of cattle revealed the presence of eggs of Fasciola hepatica and D. dendriticum in 63 and 48 cattle, respectively. The coproantigens of Fasciola hepatica were found in 148 (78.7%) cattle using ELISA. Additionally, the eggs of F. hepatica were found in 63 (33.5%) cattle by sedimentation, with the value of EPG between 17 and 83. The prevalence of D. dendriticum was determined as 25.5%, with the value of EPG between 17 and 67. Conclusion: In this study, distomatosis was detected in cattle in Agri province using coproantigen ELISA and sedimentation methods along with macroscopic examination. The findings necessitate an urgent implementation of an effective prevention and control program, which can increase the awareness of cattle breeders regarding these diseases. Furthermore, there is also a need for more detailed studies on these diseases.

The Distribution of Pathogenic Intestinal Parasites in Sivas Cumhuriyet University Faculty of Medicine Research and Application Hospital between 2006-2018

Objective: The aim of this study was to determine the distribution of intestinal parasites in patients admitted to our hospital with gastrointestinal complaints in our city harboring sociocultural and economic changes, and to show the relationship between these parasites and variables such as age, sex and year. Methods: The distribution of intestinal parasites in patients who suffered from gastrointestinal symptoms and were referred to our microbiology/parasitology laboratory from various clinics of the Sivas Cumhuriyet University Training and Research Hospital between January 2006 and December 2018 was determined. After macroscopic examination, 19,760 stool specimens were examined with Nativ-lugol, if necessary, flotation, sedimentation, trichrome and modified acid-fast, Certest Combo Card test Crypto + Giardia + Entamoeba (CerTest Biotec S.L., SPAIN) methods and 5,814 cellophane tape samples were examined with direct microscopy and the results were evaluated retrospectively. Results: Three protozoa and six helminth species were identified in the samples studied. The most frequent parasite was found to be Giardia intestinalis (6.9% n=1.363) from protozoa and Enterobius vermicularis (10.8% n=627) from helminths. Entamoeba histolytica/dispar (1.5% n=289), Cryptosporidium parvum (0.3% n=53), Ascaris lumbricoides (0.2% n=41), Trichuris trichiura (0.1% n=23), Hymenolepis nana (0.1% n=21), Taenia saginata (2.1% n=299) and Dicrocoelium dendriticum (0.01% n=1) were among other intestinal parasites. Conclusion: Between 2006-2018, while decreases in soil-borne parasitoses were observed, there was no statistically significant decrease in annual positive case rates. Despite the development of the infrastructure, parasitoses transmitted by lack of sanitation/cleaning, are still important in our province.

Molecular Characterization of Fasciola and Dicrocoelium Species Isolated from Ruminant Livestock in Qazvin, Iran.

INTRODUCTION: Fascioliasis and dicrocoeliasis are the most frequent zoonotic diseases with increasing human health problems in different parts of Iran. Two species, Fasciola hepatica (F. hepatica) and Fasciola gigantica (F. gigantica), are spread in the country. Molecular approaches have a decisive role in identifying both the species. The aim of this study was to detect Fasciola spp. and Dicrocoelium spp. by amplifying the ITS-2 and 28S rDNA gene sequence. METHODS: Overall, 30 infected liver samples were collected from the livestock of Qazvin, Iran. The adult flukes were collected from different livestock. DNA extraction and PCR amplification of ribosomal RNA gene region (ITS2) and 28S rDNA gene fragment were conducted and a phylogenetic tree was constructed. RESULT: All the isolates obtained from the cattle (No: 7) and 82.6% (No: 19) of sheep isolates were infected with F. hepatica species, whereas 17.4% (No: 4) of sheep isolates were infected with F. gigantica. It was also shown that F. hepatica was the predominant species of Fasciola present in the region. All the specimens were infected with Dicrocoelium dendriticum (D. dendriticum). CONCLUSION: Both the species of Fasciola were found in Qazvin. D. dendriticum was the sole infecting species of the Dicrocoelium genus in the livestock of the city of Qazvin. Further research studies are needed to determine the intermediate host of the parasites in the region.

Endoparasites Determined by Fecal Examination in Sheep in Erzurum Province

Objective: The aim of the current study was to determine the presence and prevalence of Eimeria and helminth species in sheep raised in Erzurum province by using fecal examination. Methods: Faecal samples were collected from a total of 784 sheep raised in Aziziye, Yakutiye and Palandöken districts between February-March 2019. The samples were examined by Fulleborn's flotation, Benedect sedimentation, and Baermann-Wetzel methods. Results: Eimeria spp. and helminths were found in 49.36% (387/784) and 74.11% (581/784) of the samples, respectively. Identified Eimeria species were as follows: E. parva (59.68%), E. ovina (51.67%), E. faurei (47.80%), E. ahsata (39.27%), E. granulosa (36.62%), E. punctata (28.42%), E. pallida (26.09%), E. ovinoidalis (18.34%), E. crandallis (16.79%), E. intricata (15.76%), E. weybridgensis (11.36%) and E. marsica (6.20%). Helminth species identified at genus/species level were Dicrocoelium spp. (33.91%), Fasciola spp. (5.68%), Paramphistomum spp. (2.58%), Moniezia spp. (5.85%), Trichostrongylid type egg (49.05%), Marshallagia spp. (38.73%), Nematodirus spp. (20.98%), Trichuris spp. (14.46%), Protostrongylus spp. (18.42%), Dictyocaulus filaria (2.41%) and Muellerius capillaris (1.38%). Conclusion: Parasitic diseases cause important economic losses in livestock industry. In following years, it is aimed to plan prevention and control strategies for the parasites detected in this area in line with the data of this study and to share this data with the animal breeders.

Morphological and morphometric variations of Dicrocoelium rileyi (Digenea: Dicrocoelidae) parasitizing Tadarida brasiliensis (Chiroptera: Molosiidae) in Mexico.

Fifty-five adult Dicrocoelium rileyi Macy, 1931 parasitizing Tadarida brasiliensis (Geoffroy, 1824) from Durango, Nuevo Leon, Puebla, Zacatecas and Mexico State were morphologically described and morphometrically analyzed. To evaluate the degree of variation among populations from the five localities, 27 morphometric measures of this species were transformed into an orthogonal factor by principal component analysis (PCA), and a posterior comparison among populations was performed using discriminant analysis of principal components (DAPC). Significant differences were observed with exceptions between the Puebla - Zacatecas and Nuevo Leon - Mexico State populations when forming three groups with an 88 % assignation. The Durango population was the most dissimilar population. These results show that the morphological traits of D. rileyi are variable among the populations in this study due to local intraspecific variation; however, some of the specimens present in the distinct localities may represent different species. Molecular analysis is necessary to accurately define whether the populations involved in our study constitute one or several species.

Dicrocoeliosis in extensive sheep farms: a survey.

BACKGROUND: This study investigated the epidemiological and molecular aspects of dicrocoeliosis in extensive sheep farms. METHODS: From 2013 to 2014, copromicroscopical analyses in 190 dairy sheep farms and anatomo-pathological inspections in six slaughterhouses were carried in Sardinia, Italy. Rectal faecal samples were analyzed using the FLOTAC® method, and anatomo-pathological examinations were based on detecting thickened terminal bile ducts (TTBDs). In addition, genetic analyses were conducted on representative DNA samples of adult Dicrocoelium spp. RESULTS: Ninety-seven (51.1%) out of 190 sheep farms were coprologically positive for Dicrocoelium spp. In the liver, on the surface and cut surface, TTBDs were reported in 40.1% (309/770) and 15.3% (118/770) of the animals examined, respectively, with an overall prevalence of 25.5% (196/770). No intraspecific genetic variation was observed among the Dicrocoelium dendriticum isolates. CONCLUSIONS: Our survey reveals the widespread presence of D. dendriticum in Sardinia, although seasonal, geographical and climatic conditions might be key factors in modulating the infection prevalence. Examining typical lesions due to D. dendriticum in the liver in abattoirs can be used as a marker for tracking chronic dicrocoeliosis infection.

A Comprehensive Retrospective Study: Intestinal Parasites in Human in Van Province

Objective: The aim of present study was to retrospectively determine the prevalence of intestinal parasites in patients, who were referred to Parasitology Laboratory in Van Yüzüncü Yil University, Faculty of Medicine during an 11-year period. Methods: Stool samples of 69633 individuals admitted to the outpatient clinics in the hospital were initially evaluated with native-Lugol, and then by flotation, sedimentation, trichrome staining, modified acid-fast staining and ELISA methods. Results: Twenty-four parasite species were identified in parasite-positive patients. At least one or more parasite species were found in 34.1% of all patients. The most commonly observed parasite was Blastocystis hominis (26.5%). Among pathogen parasites, Giardia intestinalis (G. intestinalis) was detected in 9.3%, Ascaris lumbricoides (A. lumbricoides) was detected in 2.5%, Entamoeba histolytica/Entamoeba dispar in 0.8%, Cystoisospora belli in 0.004%, Fasciola hepatica in 0.04%, Dicrocoelium dendriticum in 0.001%, Strongyloides stercoralis in 0.001% and hookworm in 0.001% of the patients. Conclusion: It was determined that, pathogen parasites such as G. intestinalis and A. lumbricoides were still observed at high rates in Van province, especially in children, and the problem of parasitosis is still continuing, although the prevalence of parasites has declined when compared to the previous years.

Hepatic Dicrocoelium dendriticum infection in a miniature horse.

A miniature horse which died following humane seizure from an Ontario farm was emaciated with serous atrophy of fat. Autopsy revealed hepatic atrophy and moderate periportal fibrosis. Eggs and trematodes seen in the liver were identified as Dicrocoelium dendriticum. This appears to be the first reported case of infection of equids in North America with Dicrocoelium dendriticum.

Infection parDicrocoelium dendriticumhépatique chez un cheval miniature. Un cheval miniature qui est mort à la suite d'une saisie humanitaire dans une ferme de l'Ontario était émacié et avait une atrophie séreuse des tissus adipeux. L'autopsie a révélé une atrophie hépatique et une fibrose périportale modérée. Des oeufs et des trématodes observés dans le foie ont été identifiés comme Dicrocoelium dendriticum. Il semblerait qu'il s'agit du premier cas signalé d'infection des équidés par Dicrocoelium dendriticum en Amérique du Nord.(Traduit par Isabelle Vallières).

Diversity and prevalence of gastrointestinal parasites in two wild Galago species in Gabon.

In this study, we characterize the diversity and estimated infection levels of gastrointestinal parasites circulating in two galago species, Galago demidoff and G. thomasi in two sites situated in the Southeastern forests of Gabon. Our study reveals that eleven parasites including nine helminthes (Ascaris spp., Ankylostoma spp., Dicrocoelium spp., Gongylonema spp., Oesophagostomum spp., Lemuricola spp., Strongyloides spp. Trichostrongylus spp. and Trichuris spp.) and two protozoans (Balantidium spp. and Entamoeba spp.) may infect Galago spp. with high infection rates. The results show that: a very similar parasite spectrum is found in both host species; all the taxa identified were previously observed in other Primate species and/or Man. They also show that age, gender and forest type may influence infection rates and/or parasite diversity found in a particular host and/or geographic area.

Importance of Land Snails in Dicrocoeliosis Epidemiology.

Dicrocoeliosis is a helminthosis caused by the small liver fluke Dicrocoelium spp. (Trematoda, Dicrocoeliidae) parasitizing in the bile ducts and gall bladder of ruminants as well as many other animal species including humans. In the biological life cycle of Dicrocoelium, land snails are first intermediate hosts and ants are second intermediate hosts. Sporocysts and cercaria, which are larval stages, live in the hepatopancreas of land snails and metacercaria, which is also the larval stage, lives in the abdomen and brain of ants. Land snails, which are the first intermediate host of this parasite in Turkey, include Helicopsis derbentina, Helicopsis protea, Helicopsis krynickii, Cernuella virgata, Trochoidea pyramidata, Cochicella acuta, Monacha carthusiana, Helicella candicans, Helix aspersa, Helix lucorum, and Chondrus tournefortianus. Dicrocoeliosis is widespread in ruminants and affects their liver, which can lead to weight loss and reduced milk production. The number of reports on dicrocoeliosis is increasing due to the expansion of dry habitats and parasites becoming resistant to antihelminthic drugs. This study provides information on the epidemiology and control methods of Dicrocoelium.

Dicrocoelium Dentriticum in Explanted Liver: Report of an Unusual Finding.

Dicrocoelium dentriticum, a member of trematode type helminths, is a liver parasite of ruminants. Humans are infected accidentally by ingestion of intermediate host, through infected ants via eating of raw vegetables or drinking of contaminated water. Infection is often asymptomatic or results in subtle symptoms; therefore, infections are usually unrecognized. However, it can produce chronic cholangitis and swelling or adenomatous proliferation in the bile ducts and lead to abdominal pain, diarrhea, fatigue, jaundice, and other symptoms. We report a 49-year-old female patient with end-stage hepatic cirrhosis from viral hepatitis B and D coinfection who underwent liver transplant. Shortly after transplant, she developed symptoms suggesting an obstructed biliary duct. Liver needle biopsy was done 24 hours after transplant to rule out rejection. Biopsy of her explanted liver was also examined pathologically. Microscopic examination of the liver needle biopsy ruled out rejection. Prepared sections of explanted liver revealed a helminth in the common bile duct. Morphologic reconstruction of helminth by microscopic findings and consultation with an expert parasitologist supported the diagnosis of Dicrocoelium dentriticum.

Evaluation of molecular methods for the field study of the natural history of Dicrocoelium dendriticum.

There is a need for improved methods for the study of the impacts of climatic and livestock management change on the epidemiology of production-limiting helminth parasitic diseases. In this study we report the application of molecular methods to describe the natural history of the small lancet fluke, Dicrocoelium dendriticum on Machair pastures on the Inner Hebridean Isle of Coll. Our results build upon those of the only previous historic field study of D. dendriticum in the British Isles that had been undertaken on the same study site. We demonstrate the value of combining conventional parasitological methods with PCR amplification of a mitochondrial DNA fragment for the detection of D. dendriticum in ants and snails, and PCR amplification of ITS2 and 28S ribosomal DNA fragments to support the species identity of the intermediate hosts, to improving understanding of the epidemiology of D. dendriticum. We report the presence of D. dendriticum infection in cattle, sheep and rabbits grazing on Machair pastures. D. dendriticum infection was identified in a high percentage of the snails, identified as Cochlicella acuta and Cernuella virgata, and in a high percentage of Formica fusca and Myrmica ruginoides ants that were collected from, or clinging to, the tops of flowers. We have identified the involvement of different intermediate host species and higher prevalences of snail and ant infection than previously reported, in part reflecting differences between the sensitivity and specificity of morphological and molecular speciation methods. Overall, our results highlight the complex life history of dicrocoeliosis and illustrate the parasite's generalist host strategy that confers potential to exploit new niches created by climatic change or grazing management for habitat conservation.

Study on the Relationship between Liver Parasitic Infections and Serum Vitamin A and ß-Carotene Status in Cattle.

OBJECTIVE: This study was conducted to evaluate the relationship between serum levels of vitamin A and ß-carotene in the liver of cattle. METHODS: A total number of 150 samples were selected according to the type of parasitic infections of the liver after postmortem examination and confirmation. Parasitic lesions in the liver were subdivided into three major parasites, including Fasciola hepatica, Dicrocoelium dendriticum, and hydatid cysts. Fifty samples were obtained from cattle without any parasitic infection as a control group. Serum levels of vitamin A, ß-carotene concentrations (µg/dL), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) activity were assayed. RESULTS: Naturally infected cattle with D. dendriticum, F. hepatica and hydatid cyst showed lower vitamin A levels. Serum ß-carotene levels were significantly decreased in all groups (p<0.05). ALT and AST activities in animals with parasitic diseases were statistically higher than in control group (p<0.01). A significant negative correlation was determined between the ß-carotene, vitamin A levels and enzyme activities of the liver in all the three types of liver infections (p<0.001). CONCLUSIONS: This study indicated that serum levels of vitamin A and ß-carotene decline was present in cattle with liver parasite infection and vitamin supplements should be supplied.

Comparison of Fecal Egg Counts and ELISA for the Diagnosis of Dicrocoelium Dendriticum Infection.

From economical point of view, Dicrocoelium Dendriticum (D. dendriticum) causes a lot of damages to the livestock industry annually. So, the rapid diagnosis of infection is very important. The diagnosis is based on egg per count of feces (EPG) test because detection according to clinical symptoms is difficult. Since EPG is not accurate and sensitive, the serological methods become important for the diagnosis of this parasite as they are more accurate in comparison to EPG test and they are able to diagnose infection in a short time. In this study, somatic and Excretory-secretory antigens (EsAg) were isolated. The ELISA test was set up according to positive and negative sera and the results which were obtained compared to those obtained by the EPG test. The prevalence of infection in 550 samples by ELISA and EPG methods were 56% and 7% respectively, which shows the significant difference between these methods in examining the rate of infection. Based on the results, the specificity and sensitivity in ELISA test were 95% and 94%, respectively. The results showed that the ELISA is a more reliable test in comparison to EPG test for the rapid diagnosis of D. dendriticum infection.

Dicrocoelium dendriticum found in a Bronze Age cemetery in western Iran in the pre-Persepolis period: The oldest Asian palaeofinding in the present human infection hottest spot region.

Dicrocoeliasis of animals and humans is caused by trematode species of the genus Dicrocoelium, mainly Dicrocoelium dendriticum in ruminants of the Holarctic region. D. dendriticum may be considered an old parasite, probably related to the appearance and diversification of Eurasian ovicaprines, occurred 14.7-14.5 million years ago. The oldest palaeoparasitological findings of Dicrocoelium in domestic animals and humans date from more than 5000 years BC in Europe. Eggs of D. dendriticum have been found in a burial of a Bronze Age cemetery (2600-2200 BC) close to Yasuj city, southwestern Iran. This is the oldest finding of D. dendriticum in the Near East, where present human infection reports are more numerous than in other world regions where human dicrocoeliasis is rare and sporadic. This palaeofinding in the Zagros mountainous chain area is of interest by its location close to Persepolis, suggesting a narrow relationship between humans and herbivorous animals in these highlands. Domestic ruminant populations of these highlands were following a repeated contact with those of the western flat lowlands of the Fertile Crescent thanks to annual altitudinal transhumance migrations of the nomadic pastoral tribes with their herds living throughout Zagros Mountains in the several millennium period BC. It is concluded that D. dendriticum spread together with sheep and goats westward throughout Europe from the Fertile Crescent during the 8000-6000 year BC period and somewhat later southward into Africa, both spreads facilitated by the low specificity of that trematode species regarding the snail and ant intermediate hosts.