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PubMed1997

Fasciola hepatica infection in farmed emus (Dromaius novaehollandiae).

OBJECTIVE: To describe two cases of infection with Fasciola hepatica in young farmed emus, subacute and chronic fasciolosis and a response to treatment of the flock with albendazole. PROCEDURE: Gross lesions were found at necropsy and hepatic lesions in microscopic examination. The parasite recovered from one emu was identified by its morphological characteristics and an egg count reduction test was carried out after treatment of the flock with albendazole. RESULTS: Hepatic lesions resembling subacute and chronic fasciolosis of ruminants were identified. An adult fluke was recovered from the liver of one of the birds and was identified as F hepatica. The eggs of the fluke were irregular in shape and size. No fluke eggs were identifiable in faeces of live emus 10 days after treatment of the flock with albendazole at a dose of 10 mg/kg. CONCLUSIONS: This is the first reported case of infection with F hepatica in farmed emus and the first report of the occurrence of Fasciola infection is the class Aves. The irregular shape and size of the eggs may be attributable to infection of an aberrant host. Treatment with albendazole eliminated eggs from the faeces of the flock.

Acute Disease↗
PubMed2002

The presence of predators modifies the larval development of Fasciola hepatica in surviving Lymnaea truncatula.

Experimental infections of Lymnaea truncatula with Fasciola hepatica were performed to study the consequences of the presence of predators (sciomyzid larvae or zonitid snails) on the characteristics of larval F. hepatica development in surviving snails. Controls consisted of infected snails that were not subjected to predators. Compared to controls, the survival rate at day 30 post-exposure, the duration of cercarial shedding, and the number of cercariae shed by surviving snails were significantly lower when predators were present in snail breeding boxes, whatever the type of predator used. In contrast, the prevalences of Fasciola infections in snails, and the length of time between exposure and the onset of cercarial shedding showed no significant variation. The progressive development of a stress reaction in surviving snails against predators during the first 30 days of experimental exposure to F. hepatica would influence snail survival during the cercarial shedding period and, consequently, the number of cercariae shed by the snails.

Animals↗
PubMedDate not supplied

Humoral response (IgG) of goats experimentally infected with Fasciola hepatica against cysteine proteinases of adult fluke.

The use of cysteine proteinases from Fasciola hepatica adult flukes for the serodiagnosis of caprine fasciolosis by means of an indirect ELISA test was studied. Two proteolytic fractions from adult fluke homogenates, with apparent molecular weights of 28 and 34 kDa (P28 and P34 respectively), were characterised as cysteine proteinases using azocasein assays and gelatin gel analysis. Both P28 and P34 fractions were electroluted and used as antigens in two different indirect ELISA tests. Serum IgG levels against P28 and P34 in goats given an experimental primary infection with 200 metacercariae or in goats given two experimental infections with 200 metacercariae were determined and compared with those observed in an uninfected control group. ELISA tests using both cysteine proteases showed a rapid and consistent detection of specific IgG in all experimentally infected goats. The IgG response to P28 was the first to be detected as early as 2-3 weeks post-infection and remained elevated throughout the experiment. The response to P34 was detected later (4-6 wpi) and disappeared in some animals at 18 wpi, while flukes were still present in the bile ducts. No significant differences were observed between the anti-P28 and anti-P34 IgG responses between animals receiving a primary or a challenge infection. The results of our study, although preliminary, are promising since the P28 ELISA described here may be a reliable method for the immunodiagnosis of F. hepatica infection in goats.

Animals↗
PubMed1994

Purification and characterisation of a second cathepsin L proteinase secreted by the parasitic trematode Fasciola hepatica.

A 29.5-kDa cysteine proteinase was purified from medium in which mature Fasciola hepatica parasites were maintained. The N-terminal sequence (14 residues) of the purified protein is similar to known cathepsin L proteinases, including a 27-kDa cathepsin L proteinase, also secreted by this parasite, which had been isolated previously in our laboratory [Smith, A. M., Dowd, A. J., Mc Gonigle, S., Keegan, P.S., Brennan, G., Trudgett, A. & Dalton, J.P. (1993) Mol. Biochem. Parasitol. 62, 1-8]. The N-terminal sequences of the 29.5-kDa and 27-kDa cathepsin L proteinases differ only in residue number seven (arginine and proline, respectively). Immunoblot studies, using antiserum that reacts with both cathepsin L proteinases, rule out the possibility of both enzymes arising from a higher molecular sized parent molecule. The reaction kinetics of the two F. hepatica cathepsin L proteinases on a variety of peptide substrates revealed that the two enzymes differ in their substrate specificity. Five peptide substrates that are cleaved with high affinity by the 29.5-kDa cathepsin L isolated in this study are not cleaved by the previously purified 27-kDa cathepsin L. The protein-modifying reagent, tetranitromethane, affected the 29.5-kDa cathepsin L proteinase only, causing inactivation of the enzyme and changing its migration in polyacrylamide gel electrophoresis. Our studies suggest that the two F. hepatica cysteine proteinases represent two distinct subclasses within the cathepsin L class.

Amino Acid Sequence↗
PubMed1990

Detoxification reactions of Fasciola hepatica cytosolic glutathione transferases.

Acidic/neutral glutathione (GSH) transferase forms have been isolated from Fasciola hepatica by a combination of GSH-affinity chromatography and chromatofocusing. Approximately 10-25% of the activity failed to interact with the GSH-affinity matrix when applied from crude cytosolic preparations. Following partial purification by chromatofocusing this GSH transferase activity did subsequently bind to the affinity matrix. The F. hepatica GSH transferases had catalytic activity with secondary lipid peroxidation products, the latter being possible natural substrates. The enzymes also interacted with a number of hydrophobic ligands including haematin and substituted phenol-based anthelmintics.

Animals↗
PubMedDate not supplied

[Fasciola hepatica seroprevalence in the Elaziğ region].

In this study, for the detection of Fasciola hepatica infection seroprevalence in Elaziğ region (Eastern Anatolia), the presence of F. hepatica IgG antibodies were investigated by using a home-made enzyme immunoassay, in the sera of 540 healthy volunteers (254 males, 286 females) from different age groups (age range: 0-81 yrs, mean age: 33 +/- 20 yrs). The total seropositivity rate in this region of our country was found 2.78%, with no differences between males and females (respectively, 2.76% and 2.8%). F. hepatica IgG positive subjects were then evaluated for the parameters of age, educational and socioeconomical status, and it was found that there were no statistically significant differences.

Adolescent↗
PubMed1983

[The structural changes of the kidney in Lymnaea truncatula Müller infected by Fasciola hepatica L].

The kidney of Lymnaea truncatula showed structural changes when infected by Fasciola hepatica. These changes first occurred at day 21 postexposure at 20 degrees C and concerned a destruction of renal epithelial cells followed by an epithelial hyperplasia. These hyperplasied epithelial cells again showed a destruction at days 49 and 70 post-exposure. The significance of these results is discussed.

Animals↗
PubMed2006

Physiological responses of insular wild black rat (Rattus rattus) to natural infection by the digenean trematode Fasciola hepatica.

Wild black rat Rattus rattus is regularly infected by the liver fluke Fasciola hepatica on Corsica. This report constitutes the only example of a murid rodent that plays an important epidemiological role for the Fasciolosis. We investigated the influence of such unusual parasite infection on black rat physiology by measuring its oxygen consumption at different ambient temperatures. Black rat energy requirements are influenced by body mass, temperature of the experiment and parasite infestation. The influence of the presence of F. hepatica was more pronounced for cold temperatures. The mean increase of 56% in oxygen requirements for infected rats is extremely high, indeed unexpected, according to previous knowledge. These high physiological constraints may be explained by the recent confrontation of the digenean and the rodent.

Animals↗
PubMed2002

Triclabendazole-resistant Fasciola hepatica: beta-tubulin and response to in vitro treatment with triclabendazole.

Resistance in Fasciola hepatica to triclabendazole ('Fasinex') has emerged in several countries. Benzimidazole resistance in parasitic nematodes has been linked to a single amino acid substitution (phenylalanine to tyrosine) at position 200 on the beta-tubulin molecule. Sequencing of beta-tubulin cDNAs from triclabendazole-susceptible and triclabendazole-resistant flukes revealed no amino acid differences between their respective primary amino acid sequences. In order to investigate the mechanism of triclabendazole resistance, triclabendazole-susceptible and triclabendazole-resistant flukes were incubated in vitro with triclabendazole sulphoxide (50 microg/ml). Scanning and transmission electron microscopy revealed extensive damage to the tegument of triclabendazole-susceptible F. hepatica, whereas triclabendazole-resistant flukes showed only localized and relatively minor disruption of the tegument covering the spines. Immunocytochemical studies, using an anti-tubulin antibody, showed that tubulin organization was disrupted in the tegument of triclabendazole-susceptible flukes. No such disruption was evident in triclabendazole-resistant F. hepatica. The significance of these findings is discussed with regard to the mechanism of triclabendazole resistance in F. hepatica.

Animals↗
PubMed2003

The immune response of regional lymph nodes during the early stages of Fasciola hepatica infection in cattle.

In this study we examined regional immune responses to Fasciola hepatica infection in the natural ruminant host. Naïve cattle and those pre-exposed to a drug-abbreviated infection were subsequently challenged and lymph nodes extracted at slaughter. In vitro proliferation and cytokine production by mononuclear cells isolated from hepatic and mesenteric lymph nodes were measured after culture with whole fluke antigen (WFA). Hepatic lymph node cells had a significantly greater response to parasite antigen than mesenteric lymph node cells (P < 0.02), although there was no difference in the magnitude of the proliferative response between naïve and pre-exposed challenged cattle. Mononuclear cells from hepatic lymph nodes produced interferon gamma, interleukin 2 and interleukin 4 after culture with parasite antigen, indicative of a mixed, T helper type 0, response. Comparison of the hepatic node response to a variety of F. hepatica antigens showed that proliferation was lower after culture with cathepsin-L, than with a high molecular weight fraction, WFA or excretory-secretory antigen. Cell culture supernatant fluid from unstimulated hepatic lymph node cells showed an IgG1 response to antigens of 48, 52-70, 82, 96 and 120-190 kDa on Western blot in pre-exposed, but not naïve, challenged animals.

Animals↗
PubMed1998

Morphological variability in Fasciola hepatica eggs in ruminants, rodents and lagomorphs.

The length and width of 1297 Fasciola hepatica eggs shed in cattle hosts, 337 in sheep and 199 in nutria, were measured from several parts of France. The data were compared with those obtained from other studies in Spain, France (where rats were also investigated), Germany and the Netherlands. One way analysis of variance and discriminant analysis were used to assess differences between host origins. The distribution of length and width of eggs were analysed using skewness and kurtosis Fisher coefficients. The eggs recovered from sheep, cattle, rodents and lagomorphs were different in size: the eggs found in rodents (length L x width W in microm: 8592) and lagomorphs (L x W in microm: 9100) were smaller than those found in sheep and cattle (L x W in microm: 10,000). These morphological differences in F. hepatica eggs were host-induced in rats (L x W in microM: 9709 in cattle to 8949 in rats) and rabbits (L x W in microm: 9709 in cattle to 8432 in rabbits). These differences in size of eggs might correspond to their being less able to develop into miracidia in less frequent hosts such as rodents and rabbits.

Analysis of Variance↗
PubMed2004

Immunological identification of Fasciola hepatica antigens containing major human T-cell and B-cell epitopes.

Fasciola hepatica whole worm homogenate (Fhwwh) separated fractions were used in enzyme linked immunoelectrotransfer blot (EITB) to identify the antigen(s) which induces antibody formation in human fascioliasis. The immuno-reactive antigens recognized by the infected patients were 25-29 kDa and 12 kDa. Antigens were biochemically purified by model 491-prep cell fraction (BIO-RAD). The capability of the purified target antigens to induce humoral and cellular responses with cells and sera of infected patients was investigated using enzyme linked immunosorbent assay (ELISA) and lymphoproliferative responses techniques. The 25-29 kDa cluster of antigen(s) were found to be more efficient in inducing lymphoproliferative response than 12 KDa, thus, it was considered as the target antigens used in the generation of human monospecific polyclonal immunopurified antibody probes (IPAb). The specificity and immunoreactivity of the IPAb with Fhwwh, F. hepatica excretory secretory products (FhESP) and S. mansoni adult worm antigen (SAWA) were evaluated by using EITB. Results showed that IPAb was immunoreactive with 25-29 and 12 kDa antigens of both Fhwwh and FhESP. It was concluded that the most immunogenic F. hepatica target antigen(s) were 25-29 and12 KDa antigens and there is a cross-reactivity between 25-29 and 12 KDa antigens in both Fhwwh and FhESP. The involvement of IPAb in antibody dependent cell mediated cytotoxicity in-vitro technique was studied. Results indicated that human neturophils were more effective in adhering to the IPAb-coated flukes at early stages of development.

Animals↗
PubMed2004

[Flow cytometry analysis of leukocytes response in rats immunized and infected with Fasciola hepatica].

Flow cytometry analysis of leukocytes response in rats immunized and infected with Fasciola hepatica. In the present experiment the differences in blood leucocytes between rats immunised intranasally with cDNA encoding F. hepatica GST, challenged with the parasite (group 1) and non-immunised infected rats (group 2) were compared. The number of leukocytes were estimated by flow cytometry on the 1, 5, 9 week after infection. Changes in the level of blood lymphocytes and monocytes were similar, with an increasing tendency in both groups. The level of eosinophils decreased to the 9th week after infection in both groups, however the number of these cells was seven times higher in control rats than in immunised rats.

Animals↗
PubMed2004

Vaccination of mice and sheep with Fh12 FABP from Fasciola hepatica using the new adjuvant/immunomodulator system ADAD.

We evaluate the ability of a Fasciola hepatica FABP native antigen (Fh12) with a new vaccination system called ADAD to protect mice and sheep against an experimental F. hepatica infection. The vaccination protocol consists of a set of two injections. The first injection contains a micelle in which two components are included, saponin from Quillaja saponaria (Qs) and/or Anapsos (A) a Polypodium leucotomos hydroalcoholic extract, both emulsified in a non-mineral oil (Montanide) in a water/oil emulsion (30/70). This is subcutaneously injected to achieve the "adaptation" of the immune system to subsequent stimuli. The second injection contains in addition the Fh12 antigen. Two different experiments were carried out using two mouse strains (BALB/c and CD-1). Mice vaccinated with Qs+A+Fh12 presented a survival rate of 40%, when compared with control groups. Furthermore, we evaluated the efficiency of the vaccination in sheep against an experimental F. hepatica challenge. The vaccinated sheep presented lower fluke recovery (24.5%), number of eggs in bile fluid (58.1%) and faeces (40.3%) than control groups. The recovered flukes were shorter (32.7%), immature (34.0%) and with lower body mass (31.6%) than non-complete vaccinated sheep. Thus, the new ADAD system could be a good alternative for future vaccination experiments against fasciolosis.

Adjuvants, Immunologic↗
PubMed1996

Involvement of excretion-secretion products from Fasciola hepatica inducing suppression of the cellular immune responses.

Normal rats i.p. injected with Fasciola hepatica excretor-secretor antigen (ESA) induced a population of spleen mononuclear (SpM) cells, which suppressed the delayed type hypersensitivity (DTH) response to parasite antigens as well as to non-related antigens (human serum albumin) by adoptive transfer. A similar effect was observed when the cell transfer was performed with SpM cells non-adherent to nylon wool. The DTH was not modified by cells transfer adherent to nylon wool in syngeneic receptor animals. The observed suppression depended on the concentration and inoculation moment of the antigen; 1.8 mg of protein ESA being enough to suppress the DTH response at the different days studied, before and after immunization with whole F. hepatica antigens. A marked suppression was observed when ESA was injected on day 7 pre-immunization. On the other hand, inoculation of ESA treated with 0.01 M sodium periodate (carbohydrate oxidant) diminished the suppressor effect found after the native ESA inoculation, indicating participation of ESA glucidic components in induced suppression. Inoculation of ESA fractions obtained from polyacrylamide gel elution with different MW range, showed that components between 12 and 23 kDa actively induced suppression to the DTH response to parasite antigens.

Animals↗
PubMed1983

Modulation of host immune responses by Fasciola hepatica: responses by peripheral lymphocytes to mitogens during liver fluke infections of sheep.

Fasciola hepatica infections of lambs (250 or 500 metacercariae) were shown to alter the proliferative responses of peripheral blood lymphocytes (whole blood culture) to mitogens at specific times postinfection (PI). Responses to concanavalin A (Con A) were significantly suppressed at weeks 4, 8, 10, and 11 PI whereas suppressed responses to phytohemagglutinin (PHA) occurred at weeks 4, 10, 11, and 16 PI. Only on weeks 4 and 6 PI were responses to pokeweed mitogen (PWM) suppressed. The fluke-induced modulation of responses appeared to be related more to specific phases of infection rather than to worm burdens.

Animals↗
PubMed1979

An experimental study of the effects of Nosema eurytremae (Microsporida: Nosematidae) on the liver fluke Fasciola hepatica.

A microsporidian parasite, Nosema eurytremae, was fed to Lymnaea trunculata infected with Fasciola hepatica. Microsporidian infection of the snail was always light, though spores were present in all tissues but the rediae became heavily infected in the parenchyma. The proportion of infected rediae increased with time and was especially high in ageing infections. Although rediae were only lightly infected when examined before cercarial release began, the infections became progressively heavier, so that towards the end of the life of the snails a high proportion of rediae were totally destroyed and contained no cercariae. Cercarial output was significantly depressed over a long period of active shedding by snails which had been hyperinfected with 1 x 106 spores and some of the liberated cercariae were themselves infected.

Animals↗