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Cheikh Tidiane Bâ - One of the best experts on this subject based on the ideXlab platform.

Momar Talla Seck - One of the best experts on this subject based on the ideXlab platform.

W A Nizami - One of the best experts on this subject based on the ideXlab platform.

  • ultrastructure and histochemistry of the digestive tract of juvenile Paramphistomum epiclitum paramphistomidae digenea during migration in indian ruminants
    International Journal for Parasitology, 1992
    Co-Authors: R G Mattison, R E B Hanna, W A Nizami
    Abstract:

    Abstract Mattison R. G., Hanna R. E. B. and Nizami W. A. 1992. Ultrastructure and histochemistry of the digestive tract of juvenile Paramphistomum epiclitum (Paramphistomidae: Digenea) during migration in Indian ruminants. International Journal for Parasitology 22 : 1089–1101. The digestive tract of juvenile Paramphistomum epiclitum consists of a foregut with a highly muscular terminal pharynx and an oesophagus, which leads to a pair of unbranched and blind-ending intestinal caeca. A syncytium lining the foregut is continuous with the external tegument and displays similar sensory papillae and secretory bodies (T1 and T2). A third type of secretory body (T3) is confined to the oesophageal cytons of newly excysted juveniles and is first evident in the syncytium by day 14 of migration. An epithelium lining the caeca is composed of a single layer of morphologically uniform cells whose apical surface is amplified by microvilli. Dense secretions synthesized in the caecal epithelium of mature cercariae are released during migration by a mechanism resembling modified apocrine discharge. The caecal epithelium of migrating juveniles undergoes a 10-fold increase in surface amplification (irrespective of growth) during its transition from a primarily secretory tissue to one apparently specialized for absorption.

  • ultrastructure and histochemistry of the protonephridial system of juvenile Paramphistomum epiclitum and fischoederius elongatus paramphistomidae digenea during migration in indian ruminants
    International Journal for Parasitology, 1992
    Co-Authors: R G Mattison, R E B Hanna, W A Nizami
    Abstract:

    Abstract Mattison R.G., Hanna R. E. B. and Nizami W. A. 1992. Ultrastructure and histochemistry of the protonephridial system of juvenile Paramphistomum epiclitum and Fischoederius elongatus (Paramphistomidae: Digenea) during migration in Indian ruminants. International Journal for Parasitology 22 : 1103–1115. The protonephridial system of juvenile Paramphistomum epiclitum and Fischoederius elongatus consists of a bilaterally symmetrical arrangement of primary, secondary and tertiary ducts which connect individual flame cells with a simple common bladder. Primary and secondary ducts are formed from columns of adjoining cells which provide an epithelial lining, whose luminal surface is elaborated with either short tubercles or lamellae. Groups of cilia project from the luminal surface at frequent intervals along secondary ducts. By contrast, the tertiary ducts and bladder are lined with a nucleated syncytium which ends at a junctional complex formed with the terminal canal. The latter is continuous with the tegumental syncytium and opens at a nephridiopore on the postero-dorsal surface. Tertiary ducts of mature cercariae contain concretions which are voided by migrating juveniles in whose tertiary ducts lipids are progressively accumulated. Evidence for the role of protonephridia in excretion and possibly in osmoregulation and ionic balance is currently examined.

  • ultrastructural observations on the redial tegument of Paramphistomum epiclitum from the planorbid snail indoplanorbis exustus
    Journal of Helminthology, 1992
    Co-Authors: T S Dunn, R E B Hanna, P H Dang, G Mattison, W A Nizami
    Abstract:

    The morphology of the tegument in the redia of Paramphistomum epiclitum (Digenea: Paramphistomidae) resembles that shown by most larval and adult digeneans; an outer surface syncytium is in continuity with the cytoplasm of in-sunken, nucleated cytons. Although tegumental cytons usually contain a single nucleus, some display up to six nuclei. The tegumental syncytium lining the pharynx of P. epiclitum rediae lack underlying cytons. The apical membrane of the tegument is elaborated by folds and microvilli, which presumably facilitate uptake of nutrients and/or exchange of ions involved in osmoregulation. A single type of secretory body, resulting from the fusion of smaller vesicles produced at Golgi complexes in the cytons, occurs throughout the tegument. Uniciliate sensory receptors occur in the surface syncytium particularly around the oral opening.

Bernard Marchand - One of the best experts on this subject based on the ideXlab platform.

Rodrigo Eduardo Fabrizio Sanabria - One of the best experts on this subject based on the ideXlab platform.

  • efficacy of oxyclozanide against adult Paramphistomum leydeni in naturally infected sheep
    Veterinary Parasitology, 2014
    Co-Authors: Rodrigo Eduardo Fabrizio Sanabria, Laura Moreno, Luis Alvarez, C Lanusse, Jorge Roberto Romero
    Abstract:

    Abstract The aim of the current study was to assess oxyclozanide (OCZ) efficacy against Paramphistomum leydeni in naturally infected adult sheep. OCZ concentrations in blood stream and gastrointestinal fluids collected from treated animals were also measured. Fifteen P. leydeni naturally infected sheep were randomly divided into two groups: untreated control (n = 5) and treated (n = 10). The treated group was orally drenched with OCZ (20 mg/kg, day 0). A second dose was administered 72 h later. Faecal samples were taken at days 0, +3 and +5. Five sheep from both groups were slaughtered at day +5. At necropsies, rumen, abomasum and small intestine were examined for adult and immature flukes. All recovered flukes were counted and the treatment efficacy was estimated. Additionally, serum and gastrointestinal fluid content (ruminal, abomasal and small intestine) samples, obtained from five treated animals at day +5, were analyzed by HPLC to measure OCZ concentrations. OCZ showed high efficacy (99%) against mature P. leydeni. The post-treatment egg reduction was also high after the first dose with values ranging from 98.4% (day +3) to 99.5% (day +5). The highest OCZ concentrations were measured in serum (20.7 ± 11.5 μg/mL) followed by the small intestinal fluid (6.00 ± 4.50 μg/mL). Very low OCZ concentrations (ranging between 0.05 and 0.02 μg/mL) were measured in ruminal and abomasal fluids. OCZ administered to sheep twice (20 mg/kg) by the oral route was highly efficacious against mature stages of P. leydeni in naturally infected sheep. Despite a high drug concentration at the intestinal fluid, OCZ efficacy against immature stages could not be assessed. OCZ efficacy and assessment of its concentration profiles in different tissues are considered a contribution to the scarce information available on this ruminant fluke.

  • Paramphistomum daubneyi characteristics of infection in three lymnaeid species
    Parasite, 2012
    Co-Authors: Rodrigo Eduardo Fabrizio Sanabria, G Dreyfuss, D Rondelaud, A Titi, Abdeslam Mekroud, P Vignoles, Jorge Roberto Romero
    Abstract:

    Experimental infections of two South American lymnaeids (Lymnaea neotropica and L. viatrix var. ventricosa) with Paramphistomum daubneyi were carried out to determine if these snail species could sustain larval development of this digenean and, if so, to specify their potential for cercarial production. A French population of Galba truncatula infected and raised according to the same protocol served as controls. In both experiments, prevalence of P. daubneyi infections in snails did not significantly differ from each other. In snail groups evaluated for cercarial shedding (first experiment), a significantly lower number of shed cercariae was noted for L. neotropica, while those from G. truncatula and L. v. ventricosa did not differ significantly from each other. Dissection of infected snails at day 65 post-exposure at 20 °C (second experiment) found significantly lower burdens of P. daubneyi rediae and cercariae in the bodies of L. neotropica than in those of G. truncatula and L. v. ventricosa. Compared to total cercarial production observed in dissected snails, the percentage of cercariae which exited from snails was 75.6% for G. truncatula, 21.6% for L. neotropica, and 91.4% for L. v. ventricosa. This last species seems to be a good candidate for metacercarial production of P. daubneyi.