Trematode Dicrocoelium Dendriticum Research Articles

3D virtual histology at the host/parasite interface: visualisation of the master manipulator, Dicrocoelium dendriticum, in the brain of its ant host

Some parasites are able to manipulate the behaviour of their hosts to their own advantage. One of the most well-established textbook examples of host manipulation is that of the trematode Dicrocoelium dendriticum on ants, its second intermediate host. Infected ants harbour encysted metacercariae in the gaster and a non-encysted metacercaria in the suboesophageal ganglion (SOG); however, the mechanisms that D. dendriticum uses to manipulate the ant behaviour remain unknown, partly because of a lack of a proper and direct visualisation of the physical interface between the parasite and the ant brain tissue. Here we provide new insights into the potential mechanisms that this iconic manipulator uses to alter its host’s behaviour by characterising the interface between D. dendriticum and the ant tissues with the use of non-invasive micro-CT scanning. For the first time, we show that there is a physical contact between the parasite and the ant brain tissue at the anteriormost part of the SOG, including in a case of multiple brain infection where only the parasite lodged in the most anterior part of the SOG was in contact with the ant brain tissue. We demonstrate the potential of micro-CT to further understand other parasite/host systems in parasitological research.

Evidence for the presence of morphine like substance and μ opiate receptor expression in Dicrocoelium dendriticum (Trematoda: Dicrocoeliidae)

Parasites for living in host’s body, evade from host’s immune system using variant methods such as production of some molecules with immunosuppressive properties. Of these immunosuppression molecules are morphine and morphine like substances. It can effect on innate and adaptive immunity and also humoral and cellular immunity. The past researches were approved the existence of morphine in the brain and adrenal of beef and in brain of mammalian and also it has been demonstrated as an immune modulator molecule in some invertebrates, some of the nematodes and also a trematode Schistosoma mansoni, But there is no document for morphine evidence in trematode Dicrocoelium dendriticum. Infection with this trematode has much importance either in health of ruminant and economic loos in the meat industry. In addition, this trematode is a zoonosis that there is no proper treatment for it in contrast with the other liver fluke, Fasciola hepatica. We assume that living for a long time in the bile ducts of host is related to morphine like substance as an immune regulatory molecule. We use RP-HPLC method for detection morphine in D. dendriticum and also using reverse transcription polymerase chain reaction (RT-PCR) for μ opioid receptor finding. According to the results D. dendriticum has endogenous morphine like material and also the existence of opioid μ receptor in this trematode was approved. Living in host bile duct for a long time without sever immunopathologycal impact, suggested that probably this worm use of morphine like material as an immunoregulatory molecule and also for escaping from host immune system.

Endoparasites of brown bears in Eastern Transylvania, Romania

Limited information is currently available on the parasite fauna of brown bears (Ursus arctos) in Transylvania, Romania. During 2011–2015 we identified endoparasites from 211 scat samples collected from free-ranging bears and 37 samples from organ tissue of adult individuals harvested by hunters in Eastern Transylvania. We found endoparasites in 40.7% of samples overall; 37.9% of scats and 56.8% of harvested bears. We identified 6 nematodes including undetermined species of the family Ancylostomatidae, Baylisascaris transfuga, Crenosoma sp., undetermined species of the order Spirurida, Trichinella sp., and Trichuris sp. We also found one undetermined protozoan species of the subclass Coccidia, the cestode Taenia sp., and the trematode Dicrocoelium dendriticum. We did not detect seasonal variation in B. transfuga incidence, nor in overall parasite prevalences. In Transylvania, brown bears’ space use overlaps with that of domestic animals, creating a potential risk for the transmission of parasite infections. Supplemental feeding of bears and other wildlife species as part of current management practices may increase the potential for parasitic infections by artificially concentrating wildlife.

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.

Helminth Fauna of the Siberian Roe (Capreolus pygargus) Digestive Tract

A helminthological study of six adult Siberian roe deer (Capreolus pygargus) individuals from Primorsky Krai was performed. The abomasa and small intestine contents were assessed. All animals were infected with nematodes, and the intensity of infection ranged from tens to hundreds of specimens. Spiculopteragia spiculoptera was the dominant species, and Mazamastrongylus dagestanica and Nematodirus filicollis were also detected. Ostertagia antipini and a minor morph of S. spiculoptera, “Rinadia mathevossiani”, were observed for the first time in Primorsky Krai. In addition, the Spirurida nematode Pygarginema skrjabini was detected in one roe, and the trematode Dicrocoelium dendriticum was found in the small intestines of two roes.

A tool for diagnosis of Dicrocoelium dendriticum infection: hatching eggs and molecular identification of the miracidium

DNA primers were designed from the 18S rRNA sequence from the relevant digenean trematode Dicrocoelium dendriticum to evaluate a polymerase chain reaction-based diagnostic method of this parasite from its eggs in faeces of naturally and experimentally infected sheep. In order to get DNA from D. dendriticum eggs, several hatching mechanisms were studied. Successful results were obtained when the eggs were frozen to -80°C and/or in liquid nitrogen and then defrosted. This method allowed the opening of the egg operculum and the liberation of the miracidium. DNA from D. dendriticum adults and from hatching egg miracidia was obtained and an amplification single band of 1.95kb was observed using primers designed for the total 18S rRNA sequence in both cases as well as when the template DNA was from adults of the closely related parasite Fasciola hepatica; in addition, a single and specific 0.8-kb band was obtained when primers based on an internal partial 18S rRNA sequence were used. The method showed to be useful not only in samples coming from adults, but in eggs from gall bladder and faeces as well. F. hepatica internal 18S rRNA primers were also designed and used as a negative control to prove that the eggs in faeces came from D. dendriticum and not from F. hepatica. A molecular tool able to detect a minimum of about 40 D. dendriticum eggs in one of the definitive host faeces has been developed for the first time and could provide a useful molecular tool to improve the conventional coprological diagnosis for detecting D. dendriticum eggs.

Halzoun, an allergic pharyngitis syndrome in Lebanon: The trematode Dicrocoelium dendriticum as an additional cause

Halzoun syndrome typically manifests in the form of an allergic pharyngitis following the consumption of raw or undercooked ovine liver. First described in Lebanon in 1905, it was initially attributed to Fasciola hepatica, while later publications have attributed it to other pathogens. There has been no definitive documentation of the pathogen causing the Lebanese Halzoun syndrome. The aim of our study was to identify the parasite responsible for the pathogenesis of the Lebanese Halzoun syndrome. 32 patients with typical clinical symptoms of Halzoun syndrome were recruited in the emergency room at our hospital from 2005 to 2007. One parasite was isolated from a patient's expectorations, and two others were isolated from pieces of a raw sheep liver retrieved from the patients’ dishes. A piece of infected goat liver intended for consumption was also collected from a local butcher. All parasites were examined microscopically for identification. All patients presented with immune allergic-like symptoms of the eyes, ears, nose, or throat. All collected parasites were identified as Dicrocoelium dendriticum. Our study has identified D. dendriticum, rather than Linguatula serrata or F. hepatica, as the prime suspect in the pathogenesis of the Lebanese Halzoun syndrome.

Extracellular Matrix in Platyhelminths, with Special Reference to the Presence of Fibronectin

AbstractThe extracellular matrix (ECM) was studied in the turbellarians Polycelis nigra and Microstomum lineare, the cestode Diphyllobothrium dendriticum and the trematode Dicrocoelium dendriticum. Routine LM staining methods for connective tissue gave positive results only in P. nigra. Positive staining reactions were observed in the subepithelial basal lamina, around the pharynx and as strings in the tissues. Peroxidase‐anti‐peroxidase and immunofluorescence methods were used to identify fibronectin. Positive results were obtained in all species. Positive reactivity to anti‐fibronectin was observed in the subepithelial basal lamina and as a thin network between the cells of the tissues. Some intracellular reactivity occurred, but the cell type was not identified. In M. lineare a strong positive reactivity was observed in the regenerating area.

Spermtail finestructure of Echinococcus granulosus and Dicrocoelium dendriticum

The axial filament complex of sperm tails of a cestode Echinococcus granulosus and a trematode Dicrocoelium dendriticum deviates from the more ubiquitous 9 + 2 pattern of cilia and flagella, but conforms to the 9 + 1 pattern that has been described for other platyhelminths. In E. granulosus the axial filaments occurred singly while they were usually found in pairs in D. dendriticum. Mitochondria were observed in D. dendriticum sperm tails but not in those of E. granulosus. In both species the coarse chromatin material was wound in a spiral configuration around the axial filament complex. Microtubules were present around the inner margin of the limiting membrane surrounding the axial filament. These microtubules followed a helical configuration along the length of the sperm tail. Some deviations from the usual filament patterns are briefly described.