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The hispid cotton rat (Sigmodon hispidus) as an experimental host for the bovine liver fluke (Fasciola hepatica).

The results of a study testing the susceptibility of the hispid cotton rat, Sigmodon hispidus, to infection with Fasciola hepatica are described. Ten cotton rats were placed into one of four test groups, one uninfected control or three animals each receiving two, five, or 10 F. hepatica metacercariae. Three of nine (33%) became infected, and two of these animals carried the infection to patency. At necropsy one animal had two mature F. hepatica within the common bile duct, and the other harbored a single fluke. Gross and microscopic changes, primarily of the liver, associated with infection are described, as are fecal egg counts throughout the duration of infection.

Animals↗

The liver flukes Fasciola gigantica and Fasciola hepatica express the leucocyte cluster of differentiation marker CD77 (globotriaosylceramide) in their tegument.

Glycosphingolipids from the parasitic liver flukes Fasciola gigantica and Fasciola hepatica were isolated and their carbohydrate moieties were structurally analysed by methylation analysis, exoglycosidase treatment, on-target exoglycosidase cleavage and matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry. For both liver fluke species, the ceramide monohexosides Gal1-ceramide and Glc1-ceramide were found in relative amounts of 1.0 to 0.1, respectively. From F. gigantica, the ceramide dihexoside was isolated in sufficient amounts to be structurally determined as lactosylceramide, Gal beta4-Glc1-ceramide, while for both liver fluke species the ceramide trihexoside was shown to be Gal alpha4Gal beta4-Glc1-ceramide, which is designated as either globotriaosylceramide, Pk-blood group antigen or CD77 leucocyte cluster of differentiation antigen. To our knowledge, this is the first report on the expression of globo-series glycosphingolipids in non-mammalian species. Ceramide analysis of ceramide monohexosides yielded as major components octadecanoic and 2-hydroxyoctadecanoic fatty acids together with C18- and C20-phytosphingosines. By the use of an anti-CD77 monoclonal antibody and the Escherichia coli Shiga toxin B1 subunit, globotriaosylceramide could be immunolocalised to the tegument of F. hepatica cryosections. The sharing of CD77 between liver flukes and their mammalian hosts fits in with the concept of molecular mimicry, which is closely parallel to the established imitation of host CD15 (Lewis X) displayed by the blood fluke Schistosoma mansoni.

Animals↗

Effects of cholinergic drugs on longitudinal muscle contractions of Fasciola hepatica.

Acetylcholine, cholinergic agonists and acetylcholinesterase inhibitors significantly decrease the amplitude and frequency of spontaneous longitudinal muscle contractions in Fasciola hepatica. In order of their effects on the inhibition of muscle contractions, the cholinergic agonists can be ranked as nicotine greater than carbachol greater than acetylcholine. High calcium ion concentration also causes a significant inhibition of contractions. Atropine, a cholinergic antagonist that acts on muscarinic receptors, significantly increases the amplitude and frequency of spontaneous contractions and completely reverses the effects of cholinomimetic drugs, including nicotine. In adult F. hepatica, the levels of acetylcholine and its precursor choline are 3.14 +/- 0.55 and 13.75 +/- 3.72 pmol/mg wet weight, respectively. The activities of choline acetyltransferase, specific acetylcholinesterase and the nonspecific cholinesterase are 1.25 +/- 0.19, 238.0 +/- 13.0, and 83.0 +/- 33.0 nmol/hr/mg protein, respectively.

Acetylcholine↗

First report of Lymnaea cousini Jousseaume, 1887 naturally infected with Fasciola hepatica (Linnaeus, 1758) (Trematoda: Digenea) in Machachi, Ecuador.

We report the first finding of Lymnaea cousini naturally infected with Fasciola hepatica in Ecuador. A sample of 70 snails was collected in April 2005 from a wetland located in a valley at approximately 3000 m a.s.l., near the locality of Machachi, Pichincha Province. The prevalence of natural infection in L. cousini was 31.43%, which is the highest value ever recorded for naturally infected lymnaeid species.

Animals↗

Treatment of Fasciola hepatica infection in horses with triclabendazole.

Thirteen thoroughbred foals with an adult infection and a presumed immature infection with Fasciola hepatica were treated with 12 mg triclabendazole/kg bodyweight. The absence of eggs from samples of faeces examined at intervals up to 110 days after treatment showed that all the animals were cured. In a second trial the same dose of triclabendazole cured 11 of 12 foals whereas nitroxynil at 7 mg/kg cured only six of 12 foals. No side effects were observed after treatment.

Animals↗

Cross protection in infections due to Schistosoma mansoni using tegument antigens of Fasciola hepatica.

Immunity to infection due to Schistosoma mansoni was induced in CBA/J mice by using a tegument antigen from Fasciola hepatica worms. Multiple immunizations resulted in up to 83% higher worm-burden reductions than did single immunizations. The vaccine also had an adverse effect on the fecundity of female schistosome worms, which resulted in a lower number of eggs per worm pair recovered from the livers of infected mice. Mice immunized once with tegument antigens of F. hepatica survived lethal doses of S. mansoni cercariae for longer periods than did control mice. These results--lowered worm-burden recoveries, lower egg burdens per worm pairs resulting in lesser numbers of granulomatous lesions, and longer survival times--in immunized mice suggest that protection against infection due to S. mansoni is possible using soluble antigens as vaccines.

Animals↗

[Polymorphism of the ND1 and CO1 mitochondrial genes in populations of liver fluke Fasciola hepatica].

Polymorphism of fragments of the ND1 and CO1 mitochondrial genes was for the first time found in four liver fluke Fasciola hepatica samples from Ukraine, Belarus, Moscow region, and Mordovia. The ND1 and CO1 fragments were respectively 292 and 433 bp in size, with polymorphic sites accounting for 2.7 and 0.9% of the total sequence. Seven haplotypes were found in the four samples; two haplotypes (A and B) were most common (29.1 and 45.8%, respectively) in the pooled sample. The haplotype frequency distribution differed among the four populations. Haplotype B prevailed in the Mordovian and Moscow region samples. In addition, these samples had a higher number of unique haplotypes (A2, A3, B2). The results testify to genetic divergence of the four geographically distant populations of F. hepatica.

Animals↗

Efficacy of albendazole against Fasciola hepatica in cattle.

Albendazole in drench formulation was administered to calves 16 weeks after infection with 400 metacercariae of Fasciola hepatica. In separate experiments, albendazole at dose levels of 10 or 15 mg/kg reduced the fluke burden by 92.84 per cent and 95.0 per cent, respectively. In another experiment, a dose level of 7.5 mg/kg given once, twice with a two-week interval, or twice with a three-week interval reduced the mean fluke burden by 43.75 per cent, 72.29 per cent and 90 per cent, respectively.

Animals↗

Humoral immune response and antigenemia in sheep experimentally infected with Schistosoma bovis. Cross-reactivity with Fasciola hepatica antigens.

Circulating antigen level, IgG antibody response to worm antigens and to excretory/secretory products (ES), and specificity to Fasciola hepatica antigens were determined in 6 Schistosoma bovis-infected sheep at weekly intervals for 15 wk. A noninfected control group was included. An enzyme-linked immunosorbent assay (ELISA) sandwich and a double-antibody ELISA test was used for antibody and antigen detection, respectively. The infection induced an early and relatively low IgG response to adult worm extract. This response was significantly elevated by 3 wk postinfection (PI), reached its maximum level at 9 wk PI, and was followed by a subsequent decrease. The response to ES antigens was slightly higher than that to adult worms, although the response started later, at 8 wk PI, and remained at its maximum level until 15 wk. A remarkable level of cross-reactivity was observed when adult F. hepatica extract was used. However, a low degree of cross-reactivity was found with ES antigen. The ELISA for circulating antigens was performed at weekly intervals for 8 wk. Antigens were detected as early as the first week of infection, although differences were statistically significant from week 5 onward. The highest values were observed at 7 week PI.

Animals↗

Mesenchyme cells in Fasciola hepatica (platyhelminthes): primitive glia?

Mesenchyme cells and their processes are found in the cerebral ganglia of the parasitic flatworm, Fasciola hepatica. The mesenchyme cell processes are found in two specialized associations within the ganglion: (i) as lamellae-like multilayer sheaths encircling the cerebral ganglia and separating it from the surrounding parenchyma cells, and (ii) invaginated into the surface of large diameter ('giant') nerve processes to form trophospongium-like relationships. Based on morphological criteria, these mesenchyme cells resemble general invertebrate glial cells suggesting that the mesenchyme cells of these flatworms may represent the earliest glial-like cell.

Animals↗

Development of host resistance to Fasciola hepatica after the elimination of primary infection with diamphenethide.

We studied the specificity of the individual developmental stages of Fasciola hepatica for evoking immune response of the host to reinfection with this parasite, whereby the primary infection was eliminated by a dose of 150 mg/kg diamphenethide administered in various intervals. In rats we observed a state of hypersensitivity demonstrated by retarded migration and growth of the flukes and the reduction in the number of sexually developed parasites. The changes were most marked, if the elimination of the immunizing infection followed 8-10 weeks after primary infection.

Acetanilides↗

[The biological control of Fossaria cubensis, the intermediate host of Fasciola hepatica, in 2 localities with different control agents].

A control was carried out on Fossaria cubensis, intermediate host of Fasciola hepatica, in two localities, by means of 2 different control agents. In one of them Helisoma duryi was used due to its ecological advantages as compared with the intermediate host (higher growth rhythm and lower generational time), and in the other Tarebia granifera was used, which has biological and ecological advantages upon most mollusks (ovoviviparous, parthenogenetic, longer life cycle and higher growth rhythm). In both localities an effective control was seen with the remarkable decrease of the host density after the introduction of the competitive agent.

Animals↗

The ionic response of the liver fluke, Fasciola hepatica to ouabain, monensin and the deacetylated (amine) metabolite of diamphenethide.

1. The ionic response of the liver fluke, Fasciola hepatica to perturbation of Na,K-pump activity has been determined by atomic absorption spectrophotometry. 2. The Na+/K(+)-ATPase inhibitor ouabain (1 x 10(-4) M) induced a marked reduction in K+ levels; Na+ and Ca2+ levels also fell. 3. The sodium ionophore monensin (1 x 10(-4) M) also caused a decrease in K+ levels, to below that of Na+. 4. Brief pretreatment with ouabain (1 x 10(-4) M, 15 min) followed by monensin treatment did not affect the decline in K+ levels, but did prevent the short-lived Na+ decline observed with monensin alone. 5. The deacetylated (amine) metabolite of the fasciolicide diamphenethide caused a short-lived drop in Na+ levels, but otherwise produced little change in ion levels within the fluke.

Acylation↗

Early pathological changes associated with Fasciola hepatica infections in white-tailed deer.

Three white-tailed deer (Odocoileus virginianus) were inoculated with 1000 metacercariae of Fasciola hepatica and examined on days 7, 14, and 28 postinoculation to determine the early response of a resistant host to this infection. It was concluded that only small numbers of the metacercariae penetrated the intestinal wall into the peritoneal cavity. Flukes that migrated to the liver penetrated through Glisson's capsule, primarily on the parietal surface. Marked fibroplasia and cellular infiltration of the capsule were induced and flukes were killed and destroyed in granulomas immediately beneath the capsule. Migration in hepatic parenchyma was minimal and immature flukes or migratory tracks were not found. There were infiltrations of eosinophils and mononuclear cells, bile duct hyperplasia and fibroplasia in portal areas. A few flukes penetrated through the diaphragm within 14 days postinoculation and on day 28 granulomas were observed on the dorsal surface of the lung where F. hepatica had penetrated this organ. The early reaction of Glisson's capsule to F. hepatica infection in white-tailed deer has not been described in cattle, sheep or swine infected with this fluke.

Animals↗