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PubMed1980

Chemoprophylaxis with diamfenetide against experimental infections of Fasciola hepatica in ruminants.

In limited trials against experimentally induced Fasciola hepatica infections, diamfenetide (N,N'-[oxybis(2,1-ethanediyloxy-4,1-phenylene)]bisacetamide) showed potential value for the prevention of acute fascioliasis in sheep and cattle. When given at a dosage of 10 mg/kg of body weight, diamfenetide was 87% effective in preventing establishment of F hepatica infections in sheep that were given the drug daily for 14 days, and was 96% effective in sheep that were given the drug for 21 days. Infective cysts (4 doses of 150 each) were given by capsule at 2-day intervals during the first week of medication. In additional trials, initial single large doses (40 to 100 mg/kg of body weight) given in conjunction with small doses each day (5 to 40 mg/kg), did not augment chemoprophylactic action. Signs of toxicosis attributable to diamfenetide were not observed. The severity of hepatic lesions ascribable to F hepatica correlated well with the degree of fluke control achieved. Small doses of diamfenetide given each day were less effective in calves than in sheep. Nevertheless, when given at dosages of 30 mg/kg daily for 11 days, the drug was 89% effective in preventing the development of F hepatica infections in two calves which were given infective cysts (4 X 100) by capsule at 2-day intervals during the first week of medication. Small doses of diamfenetide given daily were effective in preventing the establishment of F hepatica infections in ruminants.

Acetanilides↗
PubMed1985

Cell mediated immunity to liver fluke antigens during experimental Fasciola hepatica infection of cattle.

Cell mediated immunity (CMI) to Fasciola hepatica antigens was detected by lymphocyte proliferation and interleukin-2 (IL-2) production tests in cattle during the first 4 weeks following liver fluke infection. From the fifth week of infection onwards peripheral blood lymphocytes were unresponsive to fluke antigens by these in vitro tests. Investigations into the cause of this unresponsiveness found no evidence to suggest a selective loss of the IL-2 producing lymphocyte sub-population or that macrophages were responsible for the suppression or that antigen responsive cells were being sequestered in the spleen and mesenteric lymph nodes. Tests carried out on culture supernatants demonstrated the production during this unresponsive period of factors capable of suppressing in vitro responses to PHA. Although further tests failed to show antigen specific suppressor factors the presence of MHC restricted suppressor factors could not be ruled out. The early and transient appearance of CMI during F. hepatica infection of cattle indicates that delayed type hypersensitivity is unlikely to be important in protective immunity in cattle.

Animals↗
PubMedDate not supplied

Systemic vasculitis associated with Fasciola hepatica infection.

We report the case of a 50-year-old man who presented with systemic vasculitis associated with Fasciola hepatica infection. The patient presented with severe skin, kidney, spleen, ophthalmic, and neurological compromise. An immunological examination for primary vasculitis was negative and other infections were discounted by microbiological and serological analyses. The patient was treated with steroids without clinical response. The Fasciola hepatica infection was confirmed by the presence of specific immunoglobulin G (IgG) serum antibodies detected by a quantitative enzyme-linked immunosorbent assay (ELISA) with an optical density (OD) of 0.483 OD units (normal value<0.170 OD units) and a high-titre complement fixation (1/80 dilution). The patient received treatment with triclabendazole and all symptoms and systemic manifestations resolved within weeks. Hence, this previously unreported vasculitis-associated infection, if identified opportunely, can be treated and cured.

Animals↗
PubMed1993

Host effects on glutathione S-transferase activity in Fasciola hepatica.

Glutathione S-transferases (GST, E.C. 2.5.1.18) in Fasciola hepatica from sheep were previously found to be extremely variable with regard to specific GST activity and isoenzyme profile within and between parasite isolates. The effect of the host on GST activity and isoenzyme profile was examined by infecting mice, rats and cattle as well as sheep with one or the other of two isolates--either salicylanilide-resistant or salicylanilide-susceptible F. hepatica. In the case of both isolates, GST activity in hosts relatively resistant to reinfection--rats and cattle--was lower and more restricted in range compared with hosts susceptible to multiple infection--mice and sheep. In the case of the rat flukes, there was little variation in isozyme profiles whereas cattle flukes appeared to exhibit more variation than sheep flukes. In mice, despite the apparent variability in GST activity, only one GST band was found in the isoenzyme profiles. Therefore, the host appears to exert a pronounced effect on the activity and expression of GSTs in F. hepatica which may be related to variation in the immune responses of the different hosts during infection.

Animals↗
PubMed1995

Isolation of Fasciola hepatica haemoglobin.

A haemoprotein released in vitro by adult Fasciola hepatica was purified by gel filtration chromatography on Sephacryl S-200 and ion-exchange chromatography on DEAE-Sepharose. The molecule, with an apparent molecular weight of > 200 kDa, contains a haem group and has absorption spectra characteristics similar to heamoglobins. N-terminal amino acid sequence analysis revealed no similarity between the F. hepatica haemoglobin and other vertebrate or invertebrate haemoglobins. Antibodies to the haemoglobin molecule can be detected in the sera of F. hepatica-infected bovines as early as 1 week after infection.

Animals↗
PubMed1992

Analysis of ecdysteroids in the trematodes, Schistosoma mansoni and Fasciola hepatica.

Adult Schistosoma mansoni from experimentally infected mice and Fasciola hepatica recovered from ovine livers post mortem were analyzed for free and conjugated ecdysteroids by radioimmunoassay, high-performance liquid chromatography monitoring fractions by radioimmunoassay, and by capillary gas chromatography/mass spectrometry (selected ion monitoring). Both species contained ecdysone and 20-hydroxyecdysone as free ecdysteroids and as polar conjugates. F. hepatica also contained a polar conjugate of 2-deoxyecdysone. Evidence of apolar ecdysteroid conjugates was only obtained for F. hepatica. The free ecdysteroid-containing fraction of S. mansoni contained small amounts of unidentified immunoreactive material.

Animals↗
PubMed1979

Immunity in Schistosoma mansoni using antigens of Fasciola hepatica isolated by concanavalin A affinity chromatography.

Antigens of Fasciola hepatica adult worms were chromatographed using concanavalin A-Sepharose 4B. Two unbound peaks appeared in the inclusion volume (DT-1 and DT-2), and one peak was eluted with alpha-methylglucoside (E1-1). At least seven peaks were obtained by isoelectric focusing of E1-1. The largest of these peaks, with an average pI of 4.0, contained the antigens reactive with antibodies to Schistosoma mansoni. Mice immunized with DT-2 or E1-1 and challenged with S. mansoni cercariae developed 39 to 82% fewer worms than controls. DT-1 had no protective effect. Combining DT-1 and DT-2 abolished this protection. These experiments demonstrate that F. hepatica glycoprotein antigens induce in mice significant protection to infection with S. mansoni and offer an interesting approach to the study of vaccines in experimental schistosomiasis.

Animals↗
PubMed1998

[Detection and quantification of Fasciola hepatica antigens in sheep].

The diagnosis of ovine fascioliasis hepatica is presented by a sandwich ELISA with the use of monoclonal antibody ES78 previously reported for the diagnosis of bovine fascioliasis. The assay was applied to faeces of 40 sheep infected with Fasciola hepatica, 88 sheep with other parasitary infections tested by coproparasitology and 100 caprologically negative animals. Antigens of excretion-secretion of Fasciola hepatica were detected in 38 of the 40 sheep with fascioliasis and in none of the negative animals or with other parasitosis. The results show that ES78 sandwich ELISA, as in bovines, is fast, simple and useful for the diagnosis of the active infection caused by Fasciola hepatica among bovines.

Animals↗
PubMed1988

Identification of a 17-kilodalton Fasciola hepatica immunodiagnostic antigen by the enzyme-linked immunoelectrotransfer blot technique.

Sera obtained from human patients, calves, sheep, and rabbits infected with Fasciola hepatica were tested by the Falcon assay screening test enzyme-linked immunosorbent assay (FAST-ELISA) and the enzyme-linked immunoelectrotransfer blot (EITB) techniques with Fasciola hepatica excretory-secretory antigens in order to evaluate their immunodiagnostic potential. The study included sera from 13 patients infected with F. hepatica or a history suggesting fascioliasis, 5 patients infected and treated with bithionol or praziquantel (3 were cured with bithionol), 10 patients infected with Schistosoma mansoni, 6 infected with Trichinella spiralis, and 13 controls and sera from calves, sheep, and rabbits with a primary F. hepatica infection. By FAST-ELISA with F. hepatica excretory-secretory antigens, the serum samples from fascioliasis patients gave the highest absorbance values, and the schistosomiasis patient sera gave intermediate values compared with a normal human serum control. Also by FAST-ELISA, the values for serum from patients with fascioliasis decreased steadily after cure, reaching normal levels 20 to 47 weeks postcure. In contrast, the serum from two patients who had been treated but were not yet cured had high levels of antibodies for up to 3 years of infection. By EITB, the serum samples from humans, rabbits, cattle, and sheep with fascioliasis recognized two antigenic polypeptides of 17 and 63 kilodaltons (kDa) in the form of sharp bands. For humans, this recognition lasted for at least 3 years of infection. Sera from individuals with schistosomiasis mansoni or trichinosis or from normal controls did not recognize the 17-kDa F. hepatica antigenic polypeptide. However, serum from one human with S. mansoni and one with T. spiralis infection has slight bands in the 63-kDa region, suggesting cross-reactivity. Reactivity to the 17-kDa polypeptide was absent in fascioliasis patients at 1 year postcure. Reactivity to the 63-kDa polypeptide was significantly diminished in fascioliasis patients at 1 year postcure. The sera from rabbits with a primary F. hepatica infection also recognized both the 17- and 63-kDa antigenic polypeptides by week 4 of infection. Reactivity to both antigens diminished significantly 6 weeks postcure and disappeared by 8 weeks postcure. The sera from infected cattle and sheep recognized these two antigenic polypeptides by week 8 of infection. These studies suggest that the 17-kDa F. hepatica excretory secretory antigen is an excellent candidate for the immunodiagnosis of acute and chronic fascioliasis. Purification of this antigen and its application to quantitative serologic tests will permit further analysis of its predictive value to evaluate cure.

Animals↗
PubMed2002

Cysteine proteinases Fas1 and Fas2 are diagnostic markers for Fasciola hepatica infection in alpacas (Lama pacos).

Circulating antibody against Fasciola hepatica antigens was determined by enzyme-linked immunosorbent assay (ELISA) and immunoelectrophoresis in alpacas naturally exposed to F. hepatica. Serological assay parameters were established by using sera from eight infected animals and seven controls with no record of this parasitic infection. Excretory--secretory (ES-) products, Fas1- and Fas2-ELISA were used to survey 307 alpacas from a F. hepatica endemic area in the Peruvian Andes. Seroprevalence of F. hepatica infection varied from 56.7, 64.8 and 66.8% measured by Fas1-, Fas2- and ES-ELISA, respectively. The sensitivity for ES-ELISA was 95%, corresponding Fas1- and Fas2-ELISA sensitivity values were 90 and 95%. In this population, 7% of animals were positive for F. hepatica eggs in faeces, other parasites detected were Trichuris sp. (40%), Nematodirus sp. (34.6%), Lamanema sp. (12.8%) and Eimeria sp. (11.8%). The results show that F. hepatica infected animals elicit circulating antibodies against ES, Fas1 and Fas2. Fas2-ELISA may be proposed as a sensitive assay for the immunodiagnosis of fasciolosis in alpacas.

Animals↗
PubMed1998

IFN gamma and IL-10 production by hepatic lymph node and peripheral blood lymphocytes in Fasciola hepatica infected sheep.

The present study was designed to determine whether IFN gamma and IL-10 were secreted by peripheral blood mononuclear cells (PBMC) and hepatic lymph node mononuclear cells (HLNMC) from 17 Fasciola hepatica infected sheep after in vitro stimulation by Fasciola hepatica excretory-secretory products (FhESP) during the first six weeks of two different infections. The IFN gamma concentration in mononuclear cells (MC) culture supernatants was determined by sandwich ELISA. The presence of IL-10 in MC culture supernatants was determined by the capacity of these to inhibit, with or without monoclonal antibodies to IL-10, the NO production of recombinant bovine IFN gamma (rBoIFN gamma) activated monocytes. FhESP-stimulated PBMC and HLNMC produced IFN gamma in culture supernatants from DPI 7 (day post-infestation 7) to DPI 14. Culture supernatants of PBMC stimulated with FhESP first induced an increase in the NO production of rBoIFN gamma activated monocytes. After 2 or 3 weeks of infection, MC culture supernatant reduced the NO production of rBoIFN gamma activated monocytes. From DPI 35, anti-IL-10 antibodies addition restored or enhanced NO production. During sheep fasciolosis, IFN gamma production increased only until the first two weeks post infection. IL-10 could be secreted throughout the first six weeks of infection and could inhibit monocytes from DPI 35.

Animals↗
PubMedDate not supplied

Immunodiagnosis of human fascioliasis with Fasciola hepatica cysteine proteinases.

The immunodiagnosis of human infections with Fasciola hepatica using purified parasite cysteine proteinases as antigens is reported in this paper. IgG enzyme-linked immunosorbent assays (ELISAs) with 2 cysteine proteinases of 26 kDa (Fas1) and 25 kDa (Fas2), obtained from the regurgitated material of adult worms, were evaluated with serum samples from 38 patients infected with F. hepatica, from 54 patients with other parasitic infections and from 46 healthy volunteers. The diagnostic sensitivities for detection of F. hepatica infection at a serum dilution of 1 in 500 were 89% and 95% with Fas1 and Fas2 respectively. The specificity of the ELISAs was 98% for Fas1 and 100% for Fas2. IgG ELISA with Fas2 is a highly sensitive and specific assay for the immunodiagnosis of human fascioliasis.

Animals↗
PubMed1999

Eicosanoid production by adult Fasciola hepatica and plasma eicosanoid patterns during fasciolosis in sheep.

Fasciola hepatica infection in sheep is known to cause anaemia, fever and elevated levels of liver enzymes. It was hypothesised that eicosanoids play a role in these pathophysiological changes, so the pattern of plasma eicosanoids during the course of acute and chronic fasciolosis was studied in sheep infected with a single dose of 800 F. hepatica metacercariae. Blood plasma was collected weekly until week 17 p.i. from infected sheep, and from uninfected controls. Adult F. hepatica were then recovered from bile ducts and incubated for production of ES products. Eicosanoids were determined by enzyme immuno-assay in blood plasma, fluke homogenates and ES products after chromatographic purification of the samples. Fever and anaemia were seen from 3 to 12 weeks p.i. and from 8 to 17 weeks p.i., respectively. Onset of fever was accompanied by elevated liver enzyme activities (aspartate amino transferase and gamma glutamyl transferase) in the plasma. In general, the plasma levels of prostaglandin E2 (PGE2), prostaglandin I2 (PGI2) and leukotriene B4 (LTB4) were reduced during the acute and chronic stages of the infection, whereas thromboxane B2 (TXB2) was reduced only at 8 weeks p.i. The TXB2/PGI2 ratio was increased in favour of TXB2 at 3 and 11 weeks p.i. Additionally, TXB2, PGI2, PGE2 and LTB4 were detected both in ES products and in homogenates of F. hepatica. It was concluded that eicosanoid depletion in the plasma is caused by parasite-induced liver damage. The changes in eicosanoid levels are highly correlated to the clinical signs of the disease. Changes in the pattern of host plasma eicosanoids during fasciolosis, as well as parasite-derived eicosanoids, may reflect or contribute to the pathology of the disease.

Acute Disease↗
PubMed1986

Seasonal variations in egg passage of Fasciola hepatica in dairy cows in Quebec.

Seasonal changes in Fasciola hepatica egg passage were documented in 17 dairy herds in Portneuf County, Quebec (Canada). Egg passage was low or absent in spring and summer but rose in autumn to reach a peak in winter, then subsequently returned to low levels. This study suggests that there are two periods of transmission to the bovine host during the grazing season: a minor period in the spring, due to overwintered snails, and a major period in August and September due to snails that acquired the infection in May or June.

Animals↗
PubMed1994

Detection of Fasciola hepatica in infected intermediate hosts using RT-PCR.

Fasciola hepatica, the common bile duct fluke, is an economically important parasite of domestic livestock. Current research interest is directed toward an understanding of the parasite's biology at the intermediate host level. To permit study of seasonal transmission patterns and parasite/intermediate host interactions, a fasciolid-specific assay has been developed to detect infected snail vectors. This assay uses the reverse transcriptase-polymerase chain reaction (RT-PCR) to amplify specifically a region of F. hepatica small-subunit rRNA, followed by hybridization to an F. hepatica-specific probe. The assay does not cross-react with 2 trematodes outside of the Fasciolidae but does detect Fascioloides magna rRNA. Sequence alignment with additional small-subunit rRNAs shows Fasciolopsis buski would also cross-react with the assay. The detection limit of the assay is 10 fg of fluke total RNA with 5 micrograms of snail RNA added as background. Additionally, the assay detects individual infected snails immediately after miracidial exposure and throughout the parasite's development period.

Animals↗
PubMed1982

Changes in energy metabolism of the juvenile Fasciola hepatica during its development in the liver parenchyma.

Juvenile Fasciola hepatica at different stages of development were isolated from the liver parenchyma of experimentally infected rats. Their energy metabolism was studied by incubation with D-[16-14 C]glucose and compared with that of juveniles isolated immediately after in vitro emergence from the metacercarial cysts. These studies confirmed that freshly excysted juveniles have an aerobic energy metabolism, but are already fully equipped for life in the absence of oxygen. A functioning Krebs cycle was a true characteristic of all parenchymal stages of F. hepatica, but its capacity slowly decreased during development. Concomitantly, acetate became the major end product. This formation of acetate was an aerobic process and it was the most important source of energy for the exponentially growing fluke after twelve days of development. It might, therefore, be an important new target for anthelmintics. The decrease in Krebs cycle activity was not caused by a lack of oxygen nor by a decreased capacity of the respiratory chain. The freshly excysted juvenile had endogenous glycogen stores which were degraded during fasting and replenished in the presence of glucose.

Age Factors↗
PubMed1986

The behavior of juvenile Fasciola hepatica.

The behavioral repertoire of the infective stage of Fasciola hepatica was qualitatively characterized. During activation, a primary activity was the emptying of the ceca by peristaltic-like contractions. Emergence behavior comprised coordinated patterns of body movement and sucker activity specifically directed at disruption of the ventral plug. The stimulus specificity of the emergence response for glycine-conjugated cholic acid and the log dose-effect relationship of this response with glycocholic acid suggested a receptor-mediated sensory recognition. Extracts from the duodenum (departure organ) and the liver (arrival site) significantly affected the rate of locomotion and the orientation of the migratory stage. The evidence for orientation in the migrating stages is unequivocal, but the mechanisms by which they orient are unclear.

Animals↗