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Hepatic fascioliasis due to Fasciola hepatica: a two-case report.

Two cases of hepatic fascioliasis due to Fasciola hepatica were retrieved from our surgical-pathology file since the hospital's foundation in 1969 up to 2005. The diagnosis of hepatic fascioliasis was based on detection of one live fluke in a large cystic lesion in the lobectomized liver specimen in one case and of deposited eggs in the large liver specimen obtained from open biopsy in the other Hepatic fascioliasis is rather rare and almost worldwide in distribution including Thailand. The diagnosis should be considered in the patient from endemic areas consisting of the northern, northeastern and upper-central regions of the country, with a history of ingesting fresh water plants or drinking untreated water and having fever right-upper-quadrant pain or intrahepatic cystic lesion(s) together with absolute peripheral blood eosinophilia.

Adult↗

Spermatogenesis and the fine structure of the mature spermatozoon of the liver fluke, Fasciola hepatica (Trematoda: Digenea).

Spermatogenesis and the fine structure of the mature spermatozoon of Fasciola hepatica have been studied by transmission electron microscopy. The primary spermatogonia display a typical gonial morphology and occupy the periphery of the testis. They undergo 3 mitotic divisions to give rise to 8 primary spermatocytes forming a rosette of cells connected to a central cytophore. The primary spermatocytes undergo 2 meiotic divisions, resulting in 32 spermatids that develop into spermatozoa. Intranuclear synaptonemal complexes in primary spermatocytes confirm the first meiotic division. The onset of spermiogenesis is marked by the formation of the zone of differentiation which contains 2 basal bodies and a further centriole derivative, the central body. The zone extends away from the spermatid cell to form the median process; into this migrates the differentiated and elongate nucleus. Simultaneously, 2 axonemes develop from the basal bodies. During development, they rotate through 90 degrees to extend parallel to the median process. The migration of the nucleus to the distal end of the median process coincides with the fusion of the axonemes to the latter to form a monopartite spermatozoon. The mature spermatozoon possesses 2 axonemes of the 9 + '1' pattern typical of parasitic platyhelminths, 2 elongate mitochondria and a variable array of peripheral microtubules. The nuclear region of the spermatozoon is immotile. The value of sperm ultrastructure as a taxonomic tool in platyhelminth phylogeny is discussed.

Animals↗

Use of immunosorbent-purified antigens of Fasciola hepatica in enzyme immunoassays.

A monoclonal antibody specific for the T1 tegumental antigen of Fasciola hepatica was used as a solid-phase immunosorbent for the purification of T1 antigen from homogenised mature F hepatica. Material fractionated by this technique was successfully used in enzyme-linked immunoassays to detect antibodies to F hepatica in sera from sheep and cattle. Species differences in response to infection by F hepatica were demonstrated.

Animals↗

Dynamics of antigenemia and coproantigens during a human Fasciola hepatica outbreak.

In the present study the dynamics of antigenemia and coproantigens were studied in patients with Fasciola hepatica infection during an outbreak occurring in La Palma, Pinar del Río, in the West Province of Cuba. Stool and serum samples were collected from 67 patients and 40 healthy subjects. Stool samples were studied by a simple gravity sedimentation technique and an ES78 sandwich enzyme-linked immunosorbent assay (ELISA) for observation of eggs and detection of parasite coproantigens, respectively. Serum samples were also studied by the ES78 sandwich ELISA and an indirect ELISA to detect circulating antigens and antibodies, respectively. At the beginning of the study, 8 of 67 patients had patent infections and 59 had prepatent infections, which was determined by the recent consumption of lettuce contaminated with metacercariae of F. hepatica, the presence of clinical symptoms, and the absence of Fasciola eggs in their stools. Patients with prepatent infections were monitored by all techniques until patency. Circulating antigens were not detected in patients with patent infections. However, coproantigens were clearly detected in all patients with patent infections. On the other hand, 28.8% of patients with prepatent infections tested positive for circulating antigens and 81.4% tested positive for coproantigens in the first stool sample studied. Only two other coproantigen determinations were necessary to diagnose 93.2% of the patients. While circulating antigen levels diminished in all patients during the infection, coproantigen levels increased. The present study demonstrates that the ES78 sandwich ELISA is a better tool than parasitological examination for diagnosis of active early infection, since by the combination of the circulating-antigen detection assay and the coproantigen detection assay 91% of patients were able to be diagnosed at the beginning of the study. In contrast, a coprologic analysis repeated over several weeks was necessary to diagnose 100% of the patients.

Animals↗

Successful vaccination against murine Schistosoma mansoni infection with a purified 12 Kd Fasciola hepatica cross-reactive antigen.

A 12 Kd antigen was isolated from Fasciola hepatica adult worm extracts by gel filtration in Sephadex G-50 and ion exchange chromatography using DEAE Sephadex A-120. Mice immunized with this Fasciola-derived 12 Kd antigen developed antibodies to Schistosoma mansoni adult worm extracts, demonstrating its cross-reactivity with schistosomes. Vaccination of mice with microgram amounts of the antigen in Freund's adjuvant induced up to 77% reduction in worm burdens after challenge with S. mansoni cercariae. F. hepatica 12 Kd degraded by proteinase K to lower molecular weight polypeptides which still retain their antigenicity as determined by the enzyme-linked immunoelectrotransfer blot technique. Treatment with either Endoglycosidase H, neuraminidase, or dithiothreitol had no effect on its mobility in sodium dodecyl sulfate polyacrylamide gels, or in its recognition by antibody, suggesting the absence of carbohydrate moieties or disulphide bonds in relation to its antigenic determinants and also suggesting that the antigen is a pure polypeptide. These studies establish that a molecularly defined cross-reactive component of one parasitic trematode (F. hepatica) induces resistance to challenge infection with another parasitic trematode (S. mansoni). Its polypeptide nature makes recombinant DNA technology an alternative for the manufacture of a vaccine.

Animals↗

Fasciola hepatica in capybara.

The purpose of this report was to register the presence of Fasciola hepatica in an adult female capybara (Hydrocherus hydrocheris). The macro and microscopical characteristics of hepatic lesions, together with the finding of F. hepatica in mature forms indicate the possible infection of capybara by the trematode.

Animals↗

Isoenzymes of lactate dehydrogenase (EC 1.1.1.27) in Dicrocoelium dendriticum and Fasciola hepatica (Trematoda).

The isoenzymes of LDH (EC 1.1.1.27) were studied in Dicrocoelium dendriticum and Fasciola hepatica by horizontal electrophoresis on polyacrylamide gel. Six isoenzymes in D. dendriticum and four in F. hepatica were detected. Densitometric scans demonstrated that the enzyme pattern of LDH in D. dendriticum parasitizing hepatic tissue of Capra hircus was clearly different from the one obtained when the trematode parasitized other hosts such as Bos taurus or Ovis aries.

Animals↗

Metacercarial production of Lymnaea viridis experimentally infected with Fasciola hepatica.

Three groups of Lymnaea viridis snails were infected with one, three or five Fasciola hepatica miracidia, and their metacercarial production was observed. In all groups cercarial shedding commenced in some snails as early as day 27 post-infection. The duration and pattern of cercarial shedding varied from snail to snail in each group. Snails infected with three or five miracidia produced more metacercariae than those infected with a single miracidium. The overall metacercarial production was influenced by the temperature at which the snails were kept during infection.

Animals↗

[Behavior of abiotic factors and rhythm of emission of cercaria of Fasciola hepatica in Fossaria cubensis in transmission sites].

Sampling of Fossaria cubensis, main host of Fasciola hepatica in Cuba was carried out in 3 transmission sites. A higher mollusk density was found in dairies numbers 6 and 9, coinciding with the higher values of total hardness and carbonate hardness. Ammonium, nitrite, and nitrite ions showed lower values in dairy number 6. Temperature and pH did not show significant differences in the 3 biotopes. The mollusks of dairy number 6 began to emit cercarias on the 26th day after being collected; they showed an emission peak at 9 a.m. and an average of 60 cercarias emitted by each mollusk at that time of the day.

Animal Husbandry↗

A study on snail location by Fasciola hepatica using radioisotopically labelled miracidia.

A number of common freshwater molluscs were exposed to Fasciola hepatica miracidia labelled in vivo with radioselenium. Radioactivity was rapidly incorporated in all lymnaeid species tested (L. stagnalis, L. tomentosa and L. truncatula) whereas no radioactivity could be demonstrated in non-lymnaeid pulmonate species (Aplexa hypnorum, Physa acuta, Physa fontinalis, Anisus vortex, Gyraulus albus and Planorbis planorbis) or in the prosobranchs Valvata cristata and Valvata piscinalis. However, the prosobranchs Bithynia leachii, Bithynia tentaculata and Potamopyrgus jenkinsi showed a slow but significant uptake of radioactivity which was presumably explained by uptake of labelled miracidia through a 'filter-feeding' mechanism. Sphaerium corneum, a true filter-feeder, showed a similar course of uptake of radioactivity.

Animals↗

Local immune responses in colon from cattle infected with Fasciola hepatica.

Colonic mucosae isolated from eight Charolais heifers 14 weeks after oral infection with Fasciola hepatica metacercariae were voltage clamped in Ussing chambers. Antigen challenge provoked a rapid-onset, inward short circuit current in infected but not in control tissue preparations. Chloride secretion accounted for part of the response as the loop diuretic bumetanide attenuated the response to antigen by 89%. The bacterial cell wall component n-formyl-methionyl-leucyl-phenylalanine induced a similar response to antigen and partly desensitised tissues to subsequent antigen challenge, consistent with the involvement of immunocytes in the response to antigen. Infection induced an elevation in the number of tissue eosinophils compared with control colon.

Animals↗

[The redial generations of Fasciola hepatica L. in Lymnaea truncatula Müller. Multiplicity of developmental patterns].

The different rediae of Fasciola hepatica were counted in 398 snails individually exposed to single miracidium and then killed at day 30 post-exposure at 20 degrees C. When the redia n degree 1 of generation 1 was alive (327 snails), it produced rediae of generation 2 with high numbers (until 19): these rediae were precocious and could be followed by differentiation of cercariae. When the redia n degree 1 of generation 1 was degenerated (71 snails), an other redia--redia n degree 2 of generation 1 or redia n degree 1 of generation 2--produced daughter rediae with low numbers (until 9): these latter rediae differentiated in the same time as cercariae. The significance of these observations is discussed.

Animals↗

The efficacy of triclabendazole (Fasinex) against immature and adult Fasciola hepatica in experimentally infected cattle.

Eighteen Chinese cattle were experimentally infected with metacercariae of Fasciola hepatica and randomly assigned to 6 groups. Five groups of cattle were treated with a single oral dose of triclabendazole at a dose rate of 12 mg kg-1. At necropsy, the reduction in fluke burden compared with the untreated group was 85, 99.6, 99.8, 100 and 100% for cattle treated 2, 6, 8, 12 and 16 weeks after infection, respectively. Data are also presented on body weight changes during the experimental period and on serum gamma-GT activity in cattle from selected groups. Triclabendazole is considered to be safer and more efficacious than currently available fasciolicides in China.

Animals↗

Genetic variability of Brazilian populations of Lymnaea columella (Gastropoda: Lymnaeidae), an intermediate host of Fasciola hepatica (Trematoda: Digenea).

In Brazil, Lymnaea columella is the most important intermediate host of Fasciola hepatica, the etiological agent of fasciolosis, which is a parasitic disease of veterinarian and human importance. Random amplified polymorphic DNA (RAPD) was used to investigate the genetic variability within and among nine Brazilian populations of L. columella comprising 205 individuals. A number of four primers were used for analysis of molecular variance (AMOVA). Out of 83 RAPD markers, 63 (76%) were polymorphic and revealed 119 unique RAPD profiles. The levels of genetic variability found in the populations were low and most of the genetic variation was interpopulational (81.6%) when compared to intrapopulational variability (18.4%). These results are in accordance with the dynamics and distribution of the populations analyzed.

Animals↗

Acyl-CoA transferase activities in homogenates of Fasciola hepatica adults.

Succinyl-CoA is an intermediate in the formation of the fermentation product, propionate, by Fasciola hepatica adults. Acyl-CoA transferase activities are present in crude homogenates of Fasciola, which could account for the synthesis of succinyl-CoA from succinate by the transfer of CoA from either propionyl-CoA or acetyl-CoA. No transferase activity was apparent from 2-methylbutyryl-CoA or 2-methylvaleryl-CoA as was previously reported for the nematode, Ascaris suum. Heat denaturation experiments indicate that all of the Fasciola transferase activities may result from a single protein.

Animals↗

Effect of a cysteine protease inhibitor on Fasciola hepatica (liver fluke) fecundity, egg viability, parasite burden, and size in experimentally infected sheep.

Fasciola hepatica secretes proteolytic enzymes during liver invasion. The present study examined the effects of the cysteine protease inhibitor Ep-475 on sheep considering the following variables: serum levels of aspartate aminotransferase, L-lactate dehydrogenase, and gamma-glutamyltransferase, liver fluke fecundity, egg viability, parasite burden, and size. Twenty-four male sheep were randomly allocated in four groups of six animals each as follows: group A was infected with F. hepatica metacercariae and treated with 50 mg/kg of Ep-475, group B was infected and untreated, group C was uninfected and treated, and group D was uninfected and untreated. All animals were euthanized 10 weeks after the experimental infection. Serum activities of enzymes in infected animals were significantly lower in Ep-475-treated sheep than in untreated controls, although liver damage was produced. No significant reduction in total worm burden was observed between treated and untreated sheep. However, there was a significant difference on the average size, structure development, ova counts, and egg viability of liver flukes from these two groups. Results showed that Ep-475 reduces liver damage due to fasciolosis and induces an impairment of liver fluke growth and fecundity. These effects pinpoint liver fluke proteases as potential targets for pharmacological intervention.

Animals↗