Dicrocoelium spp. in cattle from Wa, Ghana: prevalence and phylogeny based on 28S rRNA.

Dicrocoeliosis is a trematode infection in cattle, sheep and goats caused by the small liver fluke, Dicrocoelium spp. Though endemic in Ghana, its disease situation is poorly understood. In the present study, the prevalence, distribution and worm load of Dicrocoelium spp. in cattle at slaughter in Wa were determined. A total of 389 cattle were screened during meat inspection for liver flukes, and polymerase chain reaction accompanied by DNA sequencing of the 28S rRNA gene was used to identify Dicrocoelium spp. Generally, prevalence of bovine dicrocoeliosis (small liver fluke) stood at 19.54 % with prevalence in males and females being 17.62 % and 21.43 %, respectively. Animals under 2 years suffered more infection than older ones (23.08 % vs. 16.80 %). Dicrocoelium infection was recorded in animals from all the communities where slaughtered cattle came from. On average, 31 flukes per infected animal were recorded. A molecular confirmatory test on seven flukes identified them as D. hospes. This preliminary study highlights the importance of bovine dicrocoeliosis in Ghana and has identified D. hospes as a causal agent. The data provides basis for further studies to appraise the trematode disease situation in animals and phylogeny of Dicrocoelium spp. circulating in Ghana.

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.

Phylogenetic relationships between Dicrocoelium chinensis populations in Japan and China based on mitochondrial nad1 gene sequences.

We carried out phylogenetic analyses of the relationships between Dicrocoelium chinensis populations in Japan and China using molecular markers. One hundred nine lancet flukes collected from Japan and China were identified as D. chinensis based on their testis orientation and the nucleotide sequences of their ribosomal ITS2. These flukes were analyzed phylogenetically using mitochondrial nad1 gene sequences. An analysis of molecular variance found that the percentage of variation between the countries was extremely high, indicating that the D. chinensis populations in Japan and China are differentiated genetically. D. chinensis mainly parasitizes wild sika deer, which is thought to originate in northeast Asia and to have colonized into Japan from the Eurasia continent in the Pleistocene glaciations. In addition, phylogenic analyses indicated that Japanese sika deer is genetically differentiated from Chinese population; therefore, we hypothesize that D. chinensis might have been introduced into Japan along with the migration of infected wild ruminants in the Pleistocene, and then the population became differentiated from the Chinese population. This study provides the nucleotide sequences of the nad1 gene of D. chinensis in Japan for the first time and shows that these sequences are useful for elucidating the phylogenetic relationships of the Dicrocoelium species prevalent in Asia.

Characterization of Dicrocoelium dendriticum haplotypes from sheep and cattle in Iran based on the internal transcribed spacer 2 (ITS-2) and NADH dehydrogenase gene (nad1).

The present study assessed whether the genetic variation among different hosts (sheep and cattle) and geographical isolates (n= 28) of Dicrocoelium dendriticum from Iran is present based on mitochondrial (nad1) and ribosomal (ITS-2) DNA markers. Molecular analysis revealed the presence of at least ten and two distinct haplotypes in the NADH dehydrogenase gene (nad1) and internal transcribed spacer 2 (ITS-2), respectively. The nad1 and ITS-2 sequence data were deposited in GenBank under accession numbers, JX050110-134 and JQ966972-3. According to the results of our study, ND-D and ITS-A are established as being the predominant haplotypes of D. dendriticum in Iran. The Iranian isolates showed a higher intraspecific genetic diversity of 0-0.97% for nad1, compared to 0-0.42% for ITS-2. The alignment and comparison of nad1 and ITS-2 sequences revealed eight and one polymorphic sites, respectively. In the nad1 sequences, six were silent and two nucleotide substitutions were responsible for amino acid alterations. A phylogenetic analysis of the sequence data revealed that host associations and geographic location are not likely useful markers for D. dendriticum haplotype classification. Consequently, sequencing results obtained from the nad1 gene as a mitochondrial marker for the first time in this study would provide a valuable tool to analyse further molecular details of D. dendriticum worldwide.

Characterization of Dicrocoelium dendriticum isolates from small ruminants in Shaanxi Province, north-western China, using internal transcribed spacers of nuclear ribosomal DNA.

The genetic variations in internal transcribed spacers (ITS) spanning ITS-1, 5.8S and ITS-2 rDNA of Dicrocoelium dendriticum, isolated from sheep and goats in four geographical regions in Shaanxi province, were examined. The lengths of ITS-1, 5.8S and ITS-2 rDNA sequences for D. dendriticum were 749 bp, 161 bp and 234 bp, respectively. Intra-specific sequence variations of D. dendriticum were 0-0.5% for ITS-1 and 0-1.3% for ITS-2 rDNA, while the inter-specific variations among species in genus Dicrocoelium in ITS-2 rDNA were 3.4-12.3%. Phylogenetic analysis based on sequences of ITS-2 rDNA showed that all D. dendriticum isolates in the present study were grouped with reference D. dendriticum isolates from sheep and goats, and D. dendriticum isolates from cattle and Japanese serow were clustered in a sister clade. However, the phylogenetic tree could not reveal geographically genetic relationships of D. dendriticum isolates in different origins and hosts. These findings provided basic information for further study of molecular epidemiology and control of D. dendriticum infection in Shaanxi province as well as in the world.

Dicrocoelium chinensis and Dicrocoelium dendriticum (Trematoda: Digenea) are distinct lancet fluke species based on mitochondrial and nuclear ribosomal DNA sequences.

Lancet flukes parasitize the bile ducts and gall bladder of a range of mammals, including humans, causing dicrocoeliosis. In the present study, we sequenced and characterized the complete mitochondrial (mt) genomes as well as the first and second internal transcribed spacers (ITS-1 and ITS-2=ITS) of nuclear ribosomal DNA (rDNA) of two lancet flukes, Dicrocoelium chinensis and D. dendriticum. Sequence comparison of a conserved mt gene and nuclear rDNA sequences among multiple individual lancet flukes revealed substantial nucleotide differences between the species but limited sequence variation within each of them. Phylogenetic analysis of the concatenated amino acid and multiple mt rrnS sequences using Bayesian inference supported the separation of D. chinensis and D. dendriticum into two distinct species-specific clades. Results of the present study support the proposal that D. dendriticum and D. chinensis represent two distinct lancet flukes. While providing the first mt genomes from members of the superfamily Plagiorchioidea, the novel mt markers described herein will be useful for further studies of the diagnosis, epidemiology and systematics of the lancet flukes and other trematodes of human and animal health significance.

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.

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.

Morphological and molecular differentiation between Dicrocoelium dendriticum (Rudolphi, 1819) and Dicrocoelium chinensis (Sudarikov and Ryjikov, 1951) Tang and Tang, 1978 (Platyhelminthes: Digenea).

Dicrocoelium dendriticum (Rudolphi, 1819) and Dicrocoelium hospes (Looss, 1907) are recognised to affect the liver of domestic and wild ruminants. A third species, Dicrocoelium orientalis which was described from musk deer in the Baikal region of the former Soviet Union and re-named to Dicrocoelium chinensis (Sudarikov and Ryjikov, 1951) Tang and Tang, 1978 was isolated from other species of deer in Asian countries and from mouflon and roe deer in Europe. Scant information is available for D. chinensis, including the range of species that act as definitive and intermediate hosts. To provide morphological and molecular evidences differentiating D. chinensis versus D. dendriticum, 239 Dicrocoelium spp. specimens were collected from sheep, cattle and sika deer from different localities in Austria, Germany and Italy. Specimens were morphologically identified based on the testes orientation, overall size, and level of maximum body width and other morphometric measurements. From this sample, 10 specimens of D. chinensis and 25 of D. dendriticum from different hosts and geographical localities were characterized molecularly through sequencing of partial 18S rDNA (approximately 1400 bp) and ITS-2 (including the 5.8S and 28S flanking regions; approximately 600 bp). Interspecific differences between D. dendriticum and D. chinensis of 0.14% and 3.8% were recorded in 18S rRNA and ITS-2 sequences, respectively. Phylogenetic analyses via Bayesian inference were conducted using sequences of ITS-2 (276 bp) and partial 28S (221 bp) of the above species of Dicrocoelium together with 20 species belonging to the Xiphidiata within the Plagiorchiida available in GenBank. Both gene regions were strongly concordant in differentiating the Dicrocoeliidae, Gorgoderidae and Plagiorchiidae and were in agreement with their current classification. Morphological and molecular characterization clearly differentiate D. dendriticum and D. chinensis as two distinct digeneans infecting ruminants. The implications on the separate status of D. chinensis on the etiology, biology and diagnosis of dicrocoeliosis are discussed.

Population genetic analysis informs the invasion history of the emerging trematode Dicrocoelium dendriticum into Canada.

Parasite distributions are constantly changing due to climate change, local and global movement of animals and humans, as well as land use and habitat change. The trematode Dicrocoelium dendriticum is a relatively recent invader of Canada, being first reported in eastern Canada in the 1930s and western Canada in the 1970s. However, historical records are scarce and its emergence is poorly understood. The establishment of this parasite in Canada provides an interesting opportunity to explore the use of population genetic approaches to help elucidate the invasion history of a relatively recently established helminth parasite. In this study, we compare the genetic diversity and population structure of a number of D. dendriticum populations from western and eastern Canada, and compare these with much longer established European populations. Two independent genetic marker systems were used; a microsatellite marker panel and a cytochrome c oxidase 1 (cox1) mitochondrial (mt)DNA sequence marker. We found distinct differences in both genetic diversity and population structure of the different Canadian populations that provide insights into their invasion histories compared with the European populations. Two populations from British Columbia, Canada - Salt Spring and Vancouver Islands - are of low diversity, show evidence of a population bottleneck and are closely related to each other, suggesting a shared recent history of establishment. These west coast populations are otherwise most closely related to those from eastern Canada and western Europe, and in contrast are genetically divergent from those in Cypress Hills, Alberta, Canada. Although the Alberta parasite population is the most recently reported in Canada, being first identified there in the early 1990s, it was the most genetically diverse of those examined and showed a strong pattern of admixture of genotypes present in western and eastern Europe. Overall, our results are consistent with a model in which western Europe is likely the source of flukes on the east coast of Canada, which were then subsequently translocated to the west coast of Canada. The most recently reported D. dendriticum population in Canada appears to have a different history and likely has multiple origins.

Distinct distribution of Dicrocoelium dendriticum and D. chinensis in Iwate Prefecture, Japan, and a new final host record for D. chinensis.

This study dealt with the morphological and molecular identification of Dicrocoelium flukes obtained from Japanese serow (Capricornis crispus) and sika deer (Cervus nippon centralis) in the twelve districts of Iwate Prefecture, Japan. Dicrocoelium dendriticum and D. chinensis were exclusively detected in the western, and coastal and eastern areas of Iwate Prefecture, respectively. This geographically distinct occurrence of the two Dicrocoelium species would be associated with the distribution of the final hosts, sika deer for D. chinensis and Japanese serow for D. dendriticum. This study also reports that Capricornis crispus is a new final host of D. chinensis.

[A historical survey of the nomenclature of the lanceolate liver fluke Dicrocoelium dendriticum]. / Ein geschichtlicher Uberblick zur Namensgebung des Lanzettegels Dicrocoelium dendriticum.

The correctness of the name Discrocoelium dendriticum given to the lanceolate liver luke is discussed in the form of a literature review. Possible reasons are discussed for the peculiar first finding of this parasite in the gut of a swordfish. D. dendriticum is regarded as the valid name of this fluke.

Some new molluscan hosts of Dicrocoelium dendriticum in Spain.

Twenty species of the family Helicidae (Gastropoda, Pulmonata) from the N.W. of Spain were tested as hosts for D. dendriticum in experimental conditions. The relationship between the egg hatching in the digestive tract and the development of sporocysts (108-110 days after egg ingestion) was studied. Three species were found to be new intermediate hosts of this trematode: Candidula intersecta , Helicella corderoi and H. jamuzensis . On the basis of the results obtained, the ecological value of the positive species in the life cycle of the parasite is discussed.

Fasciola hepatica and Dicrocoelium dendriticum: isoenzyme patterns of malate dehydrogenase and malic enzyme.

The MDH isoenzymes and ME isoenzymes (EC.1.1.1.39) in two helminth parasites, F. hepatica and D. dendriticum, obtained from two host species (Capra hircus and Ovis aries), were studied by electrophoresis on polyacrylamide gels. F. hepatica MDH showed three isoenzymatic bands; D. dendriticum MDH, only two. No difference was noted between the enzyme profiles, or the densitometric scans in samples from specimens from different host species. F. hepatica ME presented three bands, that of D. dendriticum, only two. Only in F. hepatica were differences observed between the enzyme profiles of specimens obtained from the different host species.