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At least 19 recordsLinked to original sources
PubMed2006

Phenotypic analysis of adults of Fasciola hepatica, Fasciola gigantica and intermediate forms from the endemic region of Gilan, Iran.

Fascioliasis is an important human and animal disease caused by Fasciola hepatica and Fasciola gigantica. In Iran, the distribution of these two species overlaps in most areas, including the northern human endemic province of Gilan where both fasciolids are simultaneously found in individual cattle and buffaloes. A phenotypic study of fasciolid adult flukes from naturally infected bovines from Gilan was carried out by means of an exhaustive morphometric analysis using traditional microscopic measurements and an allometric model. The Iranian fasciolids were compared to F. hepatica and F. gigantica standard populations, i.e. from geographical areas where both species do not co-exist (Bolivia and Burkina Faso, respectively). Although morphometric values somewhat overlapped, there were clear differences in allometric growth. The allometric function was adjusted to 25 pairs of variables. Results obtained revealed that Iranian F. hepatica-like specimens are larger than the F. hepatica standard and Iranian F. gigantica-like specimens are longer and narrower than the F. gigantica standard, but with smaller body area. Measurements which permit a specific differentiation in allopatric populations (distance between ventral sucker and posterior end of the body; ratio between body length and body width) overlap in the specimens from Gilan, thus proving the presence of intermediate forms. When compared to the standard populations, the different Iranian fasciolid morphs show greater differences in F. gigantica-like specimens than in F. hepatica-like specimens. This study shows that simple, traditional microscopic measurements may be sufficient for the morphometric characterisation of fasciolids, even in areas where intermediate forms are present.

Animals↗
PubMed1995

Enzyme-linked immunoelectrotransfer blot analysis of excretory-secretory proteins of Fascioloides magna and Fasciola hepatica.

Fasciola hepatica is a parasite of cattle (Bos taurus), but not of white-tailed deer (Odocoileus virginianus), while Fascioloides magna is a parasite of white-tailed deer which also infects cattle as dead-end host. Adult parasites were collected from naturally infected white-tailed deer or cattle. Excretory-secretory proteins (ESP) were obtained from each parasite. Protein banding patterns were analysed on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and probed using sera from experimentally infected deer of cattle using enzyme-linked immunoelectrotransfer blot (EITB, also known as Western blot) analysis. Protein banding patterns of the two species were different. EITB analysis of Fascioloides magna ESP using sera from Fascioloides magna infected deer or cattle identified three bands of approximately 17, 22 and 27 kDa of which the 27 kDa antigen cross-reacted with sera from Fasciola hepatica infected cattle. EITB analysis of Fasciola hepatica ESP probed with sera from Fasciola hepatica infected cattle identified three bands of approximately 15, 26 and 46 kDa. The 46 and 26 kDa ESP cross-reacted with sera from Fascioloides magna infected cattle, but not with sera from Fascioloides magna infected deer. The band at 15 kDa which reacted specifically for Fasciola hepatica infected cattle sera consisted of two protein bands close to each other as seen on the SDS-PAGE gel. The EITB reaction at approximately 17 kDa and 22 kDa of Fascioloides magna ESP, and at approximately 15 kDa of Fasciola hepatica ESP can be used for species specific diagnosis.

Animals↗
PubMed2002

A gadolinium and pH-sensitive hyperpolarization-activated cation current in acutely isolated single neurones from Fasciola hepatica.

Fasciola hepatica, a parasitic flatworm belonging to the Class Trematoda, is one of the first metazoan groups to possess a centralized nervous system. However, the electrophysiological properties of neurones in F. hepatica are largely unknown. In the present study, we acutely isolated viable neurones from F. hepatica and characterized their electrophysiological properties. A hyperpolarization-activated cation current was recorded in the cells using the whole-cell patch-clamp. The current was found to be activated slowly at membrane potentials negative to 0 mV and did not display any time-dependent inactivation. This current was reduced by 1 mM Gd3+ to the level of the leak current, while 3 mM of Cs+ had no effect. However, the current was inhibited by extracellular acidosis in the pH range 7.0-7.8, and the membrane potentials of these cells were depolarized by extracellular alkalosis in the pH range of 5.8 to 8.2. Gd3+ (1 mM), which inhibited the pH-sensitive hyperpolarization-activated cation current, also hyperpolarized the cells. In summary, we isolated single neurones from F. hepatica, and these were found to express a pH-sensitive hyperpolarization-activated cation current. This current may participate in the membrane depolarization of F. hepatica neurones during alkaline challenge.

Animals↗
PubMed2004

Glycosidase activity in the excretory-secretory products of the liver fluke, Fasciola hepatica.

Fasciola hepatica secretes proteolytic enzymes and other molecules that are essential for host penetration and migration. This mixture may include enzymes required for the degradation of supramucosal gels, which defend epithelial surfaces against pathogen entry. These contain hydrated mucins that are heavily glycosylated. Excretory-secretory products (ES) from F. hepatica were examined for a range of glycosidase activities, using synthetic 4-methylumbelliferyl glycosides as substrates. The ES product contained at least 8 different glycosidase activities, the most abundant of which were beta-N-acetylhexosaminidase, beta-galactosidase and beta-glucosidase. Alpha-fucosidase, beta-glucuronidase, alpha-galactosidase, alpha-mannosidase and neuraminidase were also present. Beta-N-acetylhexosaminidase and beta-galactosidase were present in multiple isoforms (at least 4), whereas beta-glucosidase appeared to exist as one isoenzyme with a pI < 3.8. All three enzymes had acidic pH optima (4.5-5.0). Ovine small intestinal mucin was degraded by ES at pH 4.5 or 7.0, with or without active cathepsin L, the major protease found in F. hepatica ES. The ability of F. hepatica ES to degrade mucin in the presence or absence of active cathepsin L suggests that cathepsin L is not essential for mucin degradation. The abundance of beta-galactosidase and beta-hexosaminidase in ES supports a role for these enzymes in mucin degradation.

Animals↗
PubMed1994

Field observations concerning infection of Lymnaea palustris by Fasciola hepatica.

Fasciola hepatica miracidia were experimentally introduced into five sites colonized by Lymnaea palustris over a period of 4 or 6 years. In the first four ponds, a progressive increase in the prevalence of the spring-generation juvenile snails was observed (from 0.4 to 18.1%), with a corresponding increase in the shell height of infected snails (from 3.6 to 7.8 mm). In the fifth habitat, the pond dried in 1990 causing the prevalence to drop as compared with the initial values and to subsequently increase in 1991-1992.

Analysis of Variance↗
PubMed2000

The specificity of antibody responses in cattle naturally exposed to Fasciola hepatica.

Fasciola hepatica causes significant morbidity and mortality in dairy cattle in the Andean region of Cajamarca, Peru, where prevalence of infection of up to 78% has been reported. ELISA and Western blot analyses were used to characterise antibody responses in dairy cattle to adult F. hepatica to excretory-secretory (E/S), somatic (SO) and surface (SU) antigens. Three groups of dairy cattle - calves, heifers and adult cows - naturally exposed to F. hepatica in this region, were monitored every 2 months over a 2-year period. Calves, heifers and adult cows all had antibodies which recognised a 28kDa protein in the SO preparation, whereas only adult cows had antibodies that recognised a 28kDa protein in E/S products. All three groups of cattle responded to a 60-66kDa group of proteins in E/S and SU preparations and a 17kDa antigen in SO products was recognised by antibodies from cows and heifers but not calves. The total antibody response to E/S antigens measured by ELISA, increased over time in calves and remained constantly high over the 2-year period in all three groups of cattle. Slight fluctuations in the antibody response occurred in the group of heifers and cows coinciding with seasonal changes in the level of challenge.

Animals↗
PubMed1985

31P-NMR studies of metabolite compartmentation in Fasciola hepatica.

Fasciola hepatica, the common liver fluke, is an anaerobic parasitic worm. Possible compartmentation of metabolites between different cell types, metabolic compartments, and free and macromolecule-bound species was investigated using 31P-NMR. A spectrum of the intact worm shows unusual metabolic features, among which are large amounts of glycerolphosphorylcholine, phospholipids mobile on the NMR time-scale, and free cytosolic ADP. Spectra from cells as different as those in oral sucker tissue and eggs showed similar features. Acidosis after serotonin administration was associated with parallel changes in chemical shifts of intracellular Pi and glucose 6-phosphate, suggesting that they are in the same metabolic compartment. Although 13.4 +/- 1.1 mumol/g wet wt. (n = 3) Mg2+ is present in fluke tissue, a considerable fraction is sequestered out of the cytosol. The intracellular free [Mg2+] was independently estimated from the chemical shifts of ATP and ADP as 1.6 +/- 0.5 mM and 2.9 +/- 0.7 mM, respectively. Quantitation of observable phosphate-containing metabolites in whole tissue and in perchlorate extracts demonstrated that 60% of the total ADP and 50% of the total Pi are 'NMR-invisible' in the intact fluke and therefore probably bound to macromolecules in the cells. The apparent ATP/ADP X Pi free concentration ratio is much lower in this anaerobic tissue than in mammalian oxidative tissues.

Adenosine Diphosphate↗
PubMed1992

Inhibition of proliferation of tumour cell cultures by biologically active substances isolated from the tissues of Fasciola hepatica and Fasciola hepatica-infected rat liver.

Biologically active substances (BAS) were isolated from the tissues of Fasciola hepatica L. and from F. hepatica-infected rat liver by ethanol precipitation from aqueous tissue homogenates. A marked inhibiting effect of the newly isolated BAS on hepatoma MC29 cell culture proliferation and a slight inhibiting effect of the newly isolated BAS on myeloma cell culture proliferation was found. The strongest inhibiting effect was by BAS isolated from the tissues of F. hepatica. The inhibiting effect of the BAS isolated from F. hepatica-infected liver was stronger than the effect of the BAS isolated from normal liver tissue.

Animals↗
PubMed1993

Banding patterns of Fasciola hepatica and Fasciola gigantica (Trematoda) by isoelectric focusing.

Liver flukes Fasciola hepatica and Fasciola gigantica are polymorphic and vary morphologically depending upon the host being parasitized. It is known also that mixed infection occurs where both species are present. A technique involving protein separation was used to distinguish the 2 species. Isoelectric focusing of soluble proteins was performed on polyacrylamide gels using whole-body proteins from adult flukes. Although many bands appeared common to both species and some were shared with host tissues, the banding patterns could be used to distinguish 1 species from the other. Soluble protein isoelectric focusing is simple, reproducible, and has very good resolution. It seems well suited to the differentiation of the 2 fluke species.

Animals↗
PubMed2000

Stability studies on the cathepsin L proteinase of the helminth parasite, Fasciola hepatica.

Fasciola hepatica, the liver fluke, secretes a cathepsin L cysteine proteinase. The enzyme is active over the pH range 5-9 and is remarkably stable at 37 degrees C, pH 7.0, in contrast to mammalian cathepsin Ls that are active in the acidic pH range and are inactivated within 15 min at neutral pH. The liver fluke proteinase is also very tolerant of organic solvents, particularly dimethylformamide. However, it is completely inactivated by 1 mM Hg(2+) and adversely affected by other heavy metals and divalent cations. Addition of glycerol and EDTA enhanced the liver fluke enzyme's stability at 50 degrees C, while glucose and glycerol protected the enzyme from inactivation by repeated freeze-thawing. The high stability of liver fluke cathepsin L suggests that it may have potential for use in bioindustrial applications.

Journal Article↗
PubMed2005

Fas2-ELISA in the detection of human infection by Fasciola hepatica.

Fasciola hepatica has recently emerged as a major pathogen of humans from reports on areas of endemicity and hyper-endemicity for fascioliasis. This situation is aggravated by the lack of standard assays for the screen diagnosis of F. hepatica infection in humans living in endemic areas. Our laboratory has developed an enzyme-linked immunosorbent assay (Fas2-ELISA) based on the capture of IgG antibody by a purified protein Fas2, which is an adult fluke cysteine proteinase. Fas2-ELISA exhibited 95% sensitivity and 100% specificity in 38 individuals infected with F. hepatica diagnosed by finding eggs in stools and 46 serum samples from healthy volunteers. No cross-reaction was observed with 54 serum samples from patients with ten different parasitic infections including the trematodes Paragonimus westermani and Schistosoma mansoni. The high antigenicity of Fas2 is suggested by the fact that antibodies to Fas2 rise rapidly by 1-2 weeks of infection and rise until patency at 8 weeks of infection in experimentally infected alpacas. Field screening for human fascioliasis using Fas2-ELISA and coprology in three endemic locations of the Peruvian Andes resulted in 95.5% sensitivity, 86.6% specificity in a population of 664 children in an age range of 1 to 16 years old. These results provide evidence of the clinical potential of Fas2-ELISA to diagnose fascioliasis in humans exposed to liver fluke infection in endemic areas for this parasite. Fas2-ELISA is currently developed as a standard assay for both field screening for fascioliasis in people living in endemic areas and detecting occasionally F. hepatica infected patients in clinical laboratories.

Antigens, Helminth↗
PubMed1988

Fasciola in horses in the Republic of South Africa: a single natural case of Fasciola hepatica and the failure to infest ten horses either with F. hepatica or Fasciola gigantica.

The faeces of 11 horses were examined for Fasciola spp. eggs. One of them was positive for Fasciola hepatica, a finding which was confirmed post-mortem. The 10 negative horses were subsequently infested with either F. hepatica or Fasciola gigantica, each animal receiving orally from 500-9,500 metacercariae. No clinical signs were observed and no fluke eggs were detected in the faeces, and neither immature nor adult Fasciola worms were recovered from the horses slaughtered 16-26 weeks post-infestation with F. hepatica and 28-34 weeks post-infestation with F. gigantica, respectively. The results indicate that horses have a high level of resistance to both South African Fasciola spp. Factors which can probably explain the conflicting reports for the prevalences of fascioliasis in horses throughout the world and the varying results obtained in experimental infestations are briefly considered.

Animals↗
PubMed2006

Phenotypic comparison of allopatric populations of Fasciola hepatica and Fasciola gigantica from European and African bovines using a computer image analysis system (CIAS).

The quantification of the different sizes and shapes of Fasciola hepatica and Fasciola gigantica from bovines has been achieved for the first time in natural allopatric populations. Linear measurements, areas and ratios of gravid adults and eggs of F. hepatica (from France and Spain) and F. gigantica (from Burkina Faso) were analysed using a computer image analysis system and an allometric model: (y2m - y2)/y2 = c[(y1m - y1)/y1](b), where y1 = body area or body length, y2 = one of the measurements analysed, y1m, y2m = maximum values towards which y1 and y2, respectively, tend and c, b = constants. All the measurements overlap in the two fasciolids, apart from the distance between the ventral sucker and the posterior end of the body, body roundness and body length/body width ratio. The results obtained may be useful in Fasciola species identification in countries where both species coexist.

Africa↗
PubMed2006

The serum glucose and beta-hydroxybutyrate levels in sheep with experimental Fasciola hepatica and Fasciola gigantica infection.

The influence of Fasciola hepatica and Fasciola gigantica infection on serum glucose and beta-hydroxybutyrate (beta-HOB) in sheep was evaluated. This was done by setting up two groups of sheep. The first group (n=13) was split in two sub-groups, one experimentally infected with F. hepatica (n=9) and the other (n=4) as uninfected control. A second group consisting of a sub-group experimentally infected with F. gigantica (n=9) the other sub-group (n=6) left as uninfected control was also set up. The results of weight gain, parasitological and serum liver enzymes activity (glutamate dehydrogenase [GLDH] and gamma glutamyltransferase [gamma-GT]) used in monitoring the infection showed that all infected animals developed fasciolosis. It was observed that a reduction in serum glucose levels was significantly lower (p<0.05) in F. hepatica infected sheep than in uninfected control sheep starting from 5 weeks post-infection (wpi) to the end of the experiment. Similar reduction was recorded in F. gigantica infected sheep between 8 and 19 wpi. In contrast, serum beta-HOB levels were elevated in F. hepatica infected sheep between 6 and 16 wpi and in F. gigantica infected sheep between 7 and 15 wpi. It would appear from these serum glucose and beta-HOB levels that fasciolosis does lead to energy deficiency (low glucose) and ketosis (increased beta-HOB). The decrease in serum glucose and increase in serum beta-HOB levels in infected sheep may help in understanding the interaction between fasciolosis and nutritional status of infected ruminants especially in young growing animals.

3-Hydroxybutyric Acid↗
PubMed2002

A PCR-RFLP assay for the distinction between Fasciola hepatica and Fasciola gigantica.

Fascioliasis is of well-known veterinary importance and an increasing human health problem, with reported cases in the five continents. The causative agents, Fasciola hepatica and Fasciola gigantica, present geographical distributions, which overlap in many regions of Africa and Asia, and in which the differentiation of both species is usually difficult because of the many variations in their morphological characteristics. Moreover, in humans, liver fluke classification cannot be achieved by clinical, pathological, coprological or immunological methods. The differential diagnosis between F. hepatica and F. gigantica infection is very important because of their different transmission and epidemiological characteristics. A simple and rapid PCR-restriction fragment length polymorphism (RFLP) assay, using the common restriction enzymes Ava II and Dra II, is described to distinguish between both fasciolid species. It is based on a 618-bp-long sequence of the 28S rRNA gene recently obtained from liver fluke populations of South America, Europe and Africa. This sequence showed a few nucleotide differences between both fasciolids and no intraspecific variations within each species. This assay provides unambiguous results and may be useful for both individual subject diagnosis and epidemiological surveys of humans and animals in endemic regions of sympatry.

Animals↗
PubMed1998

Triploid form of Fasciola in Japan: genetic relationships between Fasciola hepatica and Fasciola gigantica determined by ITS-2 sequence of nuclear rDNA.

The ITS-2 sequences from seven worms of the Japanese triploid form of Fasciola, two of Fasciola hepatica from Uruguay and four of Fasciola gigantica from Zambia and Indonesia were determined. The ITS-2 sequences of the Japanese triploid worms were divided into two distinct types, one of which was almost identical to that of F. hepatica and the other to F. gigantica from Indonesia.

Animals↗
PubMed2005

Fasciola hepatica and Fasciola gigantica: comparison of cellular response to experimental infection in sheep.

Cellular responses to Fasciola gigantica and to Fasciola hepatica infection in sheep were compared. Eosinophil numbers increased more quickly and strongly in F. gigantica-infected sheep than in F. hepatica-infected sheep. In both groups, peripheral blood mononuclear cell (PBMC) proliferation in response to the parasitic excretory-secretory products (ESP) showed similar kinetics. Interferon-gamma (IFN-gamma) production by ESP-stimulated PBMC was early and showed similar kinetics in both groups. Interleukin-10 (IL-10) production by FhESP-stimulated PBMC was very high throughout infection even at 0 weeks post-infection (WPI) in F. hepatica-infected sheep, while in F. gigantica-infected sheep, IL-10 production by FgESP-stimulated PBMC increased between 1 and 4 WPI. IL-10 production in F. gigantica-infected sheep was significantly lower than in F. hepatica-infected sheep during infection. The lower susceptibility to F. gigantica infection in sheep could be explained by the more intense cellular response induced by the parasite and the weaker capacity of F. gigantica to evade the immune response.

Animals↗