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.

Comparative recruitment, morphology and reproduction of a generalist trematode, Dicrocoelium dendriticum, in three species of host.

Epidemiological rate parameters of host generalist parasites are difficult to estimate, especially in cases where variation in parasite performance can be attributed to host species. Such cases are likely common for generalist parasites of sympatric grazing mammals. In this study, we combined data from experimental exposures in cattle and sheep and natural infections in elk to compare the recruitment, morphology and reproduction of adult Dicrocoelium dendriticum, a generalist trematode that has emerged in sympatric grazing hosts in Cypress Hills Provincial Park, Alberta. Overall, there were no significant differences in the recruitment of metacercariae and in the pre-patency period of adults in experimentally exposed cattle and sheep. All flukes reached reproductive maturity and the degree of reproductive inequality between individual flukes within each infrapopulation was moderate and approximately equal among the three host species. Neither fluke size nor per capita fecundity was constrained by density dependence. Thus, fitness parameters associated with growth and reproduction were approximately equivalent among at least three species of definitive host, two of which are sympatric on pastures in this Park. The generalist life-history strategy of this trematode, which is known to extend to other stages of its life cycle, has likely contributed to its invasion history outside its native range in Europe.

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.

Morphometry on lancet flukes found in Japanese sika deer (Cervus nippon centralis) captured in Iwate Prefecture, Japan.

Thirty-six flukes were collected from the livers of wild deer (Cervus nippon centralis) captured in Iwate Prefecture, Japan, and were served for morphometry. The length and/or the width of the body, suckers, testes, ovary, vitelline glands, cirrus pouch and eggs in the uterus of the flukes were measured. The distance between anterior end of the body and position of the maximal body-width or upper end of the testes were also determined. A remarked morphological characteristic was that the right and left testes did not lie tandem but lined bilaterally. Also the position of the maximal body-width did not always locate in the posterior part of the body of the fluke. The property was in accordance with those for Dicrocoelium chinensis.

Factors influencing the metacercarial intensity in ants and the size of Dicrocoelium dendriticum metacercarial cysts.

During the 1990 grazing season, ants found attached to plants were collected from sheep pastures at monthly intervals and examined for Dicrocoelium metacercariae. The species Formica pratensis and F. rufibarbis showed average metacercarial intensities of 76 and 38 respectively. In addition to the ant species, the intensity of infection was found to be dependent on the length of the ant. The volume of metacercarial cysts was influenced by the intensity per ant relative to ant length but not by the ant species or the time of ant collection.

[Micromorphology of the nervous system in the trematodes Fasciola hepatica and Dicrocoelium lanceatum]. / Mikromorfologiia nervnoi sistemy trematod Fasciola hepatica i Dicrocoelium lanceatum.

The nervous system of Dicrocoelium lanceatum and Fasciola hepatica is formed as orthogon including endon and a system of paired longitudinally oriented nerve trunks which are united by transverse commissures. The specific characters of the nervous system of D. lanceatum and F. hepatica are as follows: the location of the peripharyngeal ganglion, topographical anatomy of paired pharyngeal nerve, the character of structure and ways of direction of the paired cephalic nerve, localization and function of additional ganglia.

[Metric growth of the uterus in digenetic trematodes (author's transl)]. / Die Metrik des Uteruswachstums bei digenen Trematoden.

1. The length of the uterus of Dicrocoelium dendriticum, Pleurogenoides medians and Fasciola hepatica at different stages of development is correlated with the corrected size of the body (parallel length x breadth). 2. The data plotted in a log-scale show for all three species a sigmoid curve with linear middle section. 3. The function y = ax + ac(xw - x)3 + b(y = log length of the uterus, x = log length of the body, xw = log length of the body at the turning point) fits very well to the data obtained from Dicrocoelium dendriticum. The constants a, ac and b were determined numerically. The function is valid also for Pleurogenoides medians and Fasciola hepatica but with other constants. 4. The linear middle section of the sigmoid curve may be interpreted by allometric growth. During this phase of development the uterus is tubelike. 5. During the earliest stages of development the uterus forms a solid cord of cells (three-dimensional growth) and grows slower than in a later stage after formation of a cell-free interior (two-dimensional growth). 6. The latest phases of development are characterized by a small increase in length of the uterus due to the three-dimensional dilatation by the produced eggs. 7. The computed function is considered as a modification of the law of allometric growth Y = B . Xa, respectively y = ax + b (log Y = y, log X = x).

[New data on Dicrocoelium hospes Looss, 1907: anatomy of the adult and life cycle. Preliminary paper (author's transl)]. / Données nouvelles sur Dicrocoelium hospes Looss, 1907: anatomie de l'adulte et cycle évolutif. Note préliminaire

The morphological and anatomical studies of Dicrocoelium hospes Looss, 1907, from Togo set off several differences with Dicrocoelium lanceolatum Rudolphi, 1819: shape and dimensions of the body, shape and disposition of the testes, shape, dimensions and location of the vitellaria, structure of the uterus coils. The first intermediate host is found, they are three species of Limicolaria, one of them being L. aurora. The cercaria is described, its chaetotaxy confirms the validity of species D. hospes. Two species of ants: Dorylus sp. and Crematogaster sp. may be the second intermediate host.