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[Epidemiological data on human distomatosis (Fasciola hepatica L.) in the Limousin region of France. The species of plants eaten and snail hosts].

These epidemiological studies concern 187 cases of human fasciolasis which occurred in the region of Limousin, France on a period of 24 years. Four species of plants have been eaten: Nasturtium officinale, Roripa silvestris, Taraxacum gr. officinale, Valerianella olitoria. These plants have been eaten during all months of the year, but with higher numbers in July-August and from November to February. The cases of human fasciolasis almost take place on all years, but their numbers are high in years showing a very important infestation of cattle by Fasciola hepatica. In 2/3 of cases, the plants come from stations situated out of cattle pastures. The water-cress almost comes from natural stations or from familial plantations. Five species of snails have been observed in these stations: Lymnaea glabra, L. palustris, L. peregra, L. stagnalis, L. truncatula. The young snails of these species experimentally have been observed. The significance of these results is discussed.

Animals↗

Anthelmintic suppression of Fasciola hepatica infections in sheep.

In an experiment to examine the use of anthelmintics to suppress the faecal egg output of Fasciola hepatica from sheep and reduce the prevalence of infection on a sheep farm with a history of chronic fasciolosis, triclabendazole was administered four times annually for three years. During the first year, treatments in April, June, August and October failed to reduce the prevalence. In the subsequent two years the first annual treatment was brought forward to January and February, and the prevalence was reduced by 74.6 and 69.7 per cent, respectively. The mean plasma gamma-glutamyl transpeptidase concentration of the flock was significantly reduced from 55.9 units/litre before the experiment to 40.9 and 38.3 units/litre. In the second and third years the packed cell volume increased from 0.29 litre/litre to 0.36 litre/litre and the percentage of infected Lymnaea truncatula decreased to zero.

Animals↗

Resistance of Fasciola hepatica against triclabendazole in cattle and sheep in The netherlands.

In the winter of 1998/1999, sheep on a farm in the province of North Holland, The Netherlands, died from subacute and chronic liver fluke disease despite four previous treatments with triclabendazole (TCBZ). Faecal examinations of sheep and cattle on the farm showed high number of liver fluke eggs. In a randomised clinical trial, the fluke egg output was monitored weekly for 3 weeks in sheep which were treated with TCBZ or with closantel; in dairy cows treated with TCBZ or with clorsulon; and in heifers treated with TCBZ or clorsulon. The results showed a significant reduction of 99.7, 98.1 and 99.2%, respectively, in fluke egg output at 21 days in all non-TCBZ treated animals. TCBZ treatment produced percentage decreases of 15.3, 4.3 and 36.6%, respectively. These results are highly indicative of the presence of TCBZ-resistant Fasciola hepatica in sheep and cattle on this farm.

Animals↗

[Choledochal obstruction due to Fasciola hepatica (author's transl)].

A 45-year-old woman was admitted in July, 1976 with an acute cholecystitis without jaundice. She had suffered from hepatic colic without fever, jaundice, diarrhea or allergic episodes for the past 8 years. The physical examination only revealed an elective pain on the cystic point. Laboratory data were unremarkable, except for a 12 percent eosinophils. The cholecystogram showed a cholelithiasis. The lithiasis was confirmed during the surgical operation and a fasciolasis was diagnosed after one and 10-12 parasites had been found into the cystic and common bile duct, respectively. A cholecistectomy and choledochoduodenostomy were performed. The patient was treated with 60 mg dehydroemetine during 10 days and 500 mg chloroquine during the other next 10 days. Eggs of Fasciola hepatica were found in the stool culture. The follow-up examinations 3 months and a year after surgery were completely normal. The national literature on this topic is reviewed and the clinical manifestations and therapy of this disease are commented on.

Chloroquine↗

Gross anatomy of the muscle systems of Fasciola hepatica as visualized by phalloidin-fluorescence and confocal microscopy.

Neuropeptides, biogenic amines and acetylcholine are expressed abundantly within the nervous systems of parasitic flatworms, and are particularly evident in the innervation of the musculature. Such associations have implicated the nervous system in locomotion, host attachment and reproductive co-ordination. Information on the muscle systems of parasitic flatworms is generally sparse, in particular those muscles associated with the reproductive system, intestinal tract and attachment apparatus. Also, the use of sectioned material has left description of the 3-dimensional organization of the musculature largely unrecorded. Using fluorescein isothiocyanate (FITC)-labelled phalloidin as a site-specific probe for filamentous actin, applied to whole-mount preparations of adult Fasciola hepatica and examined by confocal scanning laser microscopy, the present work reports on the organization of the major muscle systems in this trematode parasite. A highly regular array of outer circular, intermediate longitudinal and inner diagonal fibres distinguishes the body wall musculature, which is also involved in the development of both ventral and oral suckers. Circular fibres dominate the duct walls of the male and female reproductive systems, whereas the muscles of the intestinal tract have a somewhat diffuse arrangement of fibres. An understanding of the structural complexity of the muscle systems of parasitic flatworms is considered as fundamental to the interpretation of results from physiological experiments.

Actins↗

Allopatric combination of Fasciola hepatica and Lymnaea truncatula is more efficient than sympatric ones.

Parasites are capable of rapid evolutionary changes relative to their hosts, due to short life cycle, short generation time, and high fecundity. The direction of the evolution of parasite virulence can be studied in cross-transfer experiments, combining hosts and parasites from different localities, and comparing the outcome of established (sympatric and potentially locally adapted) and novel (allopatric) combinations of hosts and parasites. We aimed to compare the compatibility with snails hosts, the infectivity of metacercariae in rabbits and rats, and the fitness among different combinations (French-FF and Spanish-SS sympatries and allopatry-FS). The first isolate of Fasciola hepatica and its corresponding intermediate host, Lymnaea truncatula originated from Lugo's northwestern Spain. The second isolate of parasite and snail was collected in the Limoges area in central France. The Spanish snails were more susceptible to their sympatric trematode than the French snails. The Spanish flukes were more infective to intermediate hosts (snails) than the French flukes, but subsequent definitive hosts (rats or rabbits) infections remained similar. The estimated fitness was low in sympatric infections and highly similar (from 4.7 to 5.3). The fitness similarity corresponds, however, to different variations in life-history traits that could represent different strategies among the host-parasite local combinations. The infection rate in snails, metacercarial productivity, metacercarial infectivity, and the estimated fitness were better for allopatric combination (FS). The susceptibility data showed a higher efficiency of flukes in the allopatric snail population than in their local snail population. However, our results were obtained after one generation and from a single isolate and it remains to be determined if all allopatric fluke-snail isolates may present a better fitness. Nevertheless our results indicate that introduction of liver fluke-infected cattle should be monitored carefully, as it could result in the introduction of more efficient parasites.

Animals↗

Fasciola hepatica miracidia are dependent on respiration and endogenous glycogen degradation for their energy generation.

It is generally accepted that free-living stages of parasitic helminths are dependent on aerobic degradation of endogenous energy sources for their energy generation. This concept, however, is not the result of extensive experimental evidence, but originated mainly intuitively as oxygen is widely available in their habitat and these stages generally have a small size. Schistosoma mansoni, the sole parasitic helminth whose energy metabolism has been studied throughout its life-cycle indeed has aerobically functioning free-living stages. However, large differences exist in energy metabolism between adult stages of distinct parasitic helminths, and caution should be taken in predicting that all free-living stages of all parasitic helminths have the same, aerobic energy metabolism. Hence, this report studied the energy metabolism of Fasciola hepatica miracidia and demonstrated that F. hepatica miracidia are also dependent on aerobic degradation of their endogenous glycogen stores by glycolysis and on Krebs cycle activity for energy generation. However, in contrast to S. mansoni, F. hepatica miracidia cannot function anaerobically, as inhibition of the respiratory chain blocked motility and carbohydrate degradation, and finally resulted in death of the miracidia. Therefore, this report demonstrated that differences exist between miracidia of distinct species, in pre-adaptation of their energy metabolism to the occasional hypoxic conditions within their next host.

Animals↗

Importance of T-cell-dependent inflammatory reactions in the decline of microsomal cytochrome P450 concentration in the livers of rats infected with Fasciola hepatica.

The concentration of cytochrome P450, measured spectrophotometrically in microsomal preparations from the livers of rats infected with 30 metacercariae of Fasciola hepatica, declined by approximately 50% at 3 weeks post-infection. Treatment of infected rats with the anti-inflammatory agent dexamethasone (2 mg/kg at 48 h intervals for 8 days prior to assay) abolished the decline in P450 content. Assay of P450 in infected congenitally athymic (nude) rats showed normal levels. These results demonstrate that the T-cell-dependent inflammatory response in the liver of the host is a necessary factor in the development of the decline in hepatic P450, which is known to compromise the metabolism of certain drugs in infected hosts.

Animals↗

[Fasciola hepatica. study of a series of 37 patients].

BACKGROUND: To analyze the clinical, bacteriologic, diagnostic and therapeutic features of patients with Fasciola hepatica (FH) in our hospital. PATIENTS AND METHOD: We reviewed all the patients with a diagnosis of fascioliasis from 1975 to 1999 in the Aranzazu Hospital in San Sebastián (Guipúzcoa, Spain). Diagnosis was made by direct vision of adult parasites during surgery and/or the presence of ova in stool examinations and/or positive serologic tests in patients with symptoms consistent with parasitosis. RESULTS: Thirty-seven patients were included (23 men and 14 women), aged 19 to 71 years. Ingestion of watercress was confirmed in 27. Seven cases occurred as part of familiar outbreaks. Thirty-two were in the liver invasive stage and in 5 the biliary tree was invaded. The most common features were eosinophilia (91.8%), malaise and weight loss (75.6%), elevated alkaline phosphatase (74.2%), and abdominal pain (72.9%). Adult worms in the biliary ducts were observed in 3 patients and ova in feces were observed in 6. In 13 of 27 patients indirect hemagglutination test was ( 1/1,280. Data significant to confirmation of liver involvement were provided by laparoscopy in 12 of 13 patients and by imaging techniques in 13 of 31 patients. Four patients had cholelithiasis and of these, 2 also showed adult parasites in the common bile duct. Three patients underwent surgery. Therapy with dehydroemetine and/or bithionol was followed by complete remission in 30 patients, although 6 required repeat treatment cycles. The remaining 4 patients were cured by praziquantel. CONCLUSIONS: Most of the patients in these series reported consumption of watercress and all patients showed the symptoms typical of parasite disease. Imaging techniques proved to be of great utility in confirming the diagnosis of hepato-biliary disease. In most of the patients therapy with dehydroemetine and/or bithionol (in one or several cycles) was followed by complete remission.

Adult↗

Fasciola hepatica and Paramphistomum daubneyi: field observations on the transport and outcome of floating metacercariae in running water.

Experimental investigations in eight open drainage ditches and furrows from central France were carried out to analyse the dispersal of floating metacercariae of two digenean species by running water and to determine the outcome of larvae which settled on Nasturtium officinale (watercress). The frequencies of larvae found after their transport by water ranged from 33% to 49.7%, thus indicating that more than half of the metacercariae used in this experiment had fallen to the bottom of the water during this transport. The nature of the site (furrow, or ditch supplied by a spring) had a significant effect on the distribution of floating larvae, while the digenean species had no effect. Low percentages of metacercariae on watercress were noted in furrows (3.5-4.3% of larvae) and ditches (0.8-1.3%). When the watercress grew, most larvae that had settled on leaves and stems died but there were always several living metacercariae on this plant (0.7-1.5% of larvae for Fasciola hepatica and 0.2-0.5% for Paramphistomum daubneyi). The weak buoyancy of these floating cysts on running water limited their dispersal and, consequently, led to a real diminution of risks incurred by definitive hosts towards these metacercariae.

Animals↗

Serological and biochemical follow-up in cattle naturally infected with Fasciola hepatica, and comparison with a climate model for predicting risks of fasciolosis.

Several biological parameters were measured in 31 heifers naturally infected with Fasciola hepatica during one grazing season in the Belgian Ardennes. A forecast model based on daily temperature used to assess the risk of fasciolosis was fitted to this assay. Cattle were turned out to two pastures. Each pasture was divided into two plots: one was treated with calcium cyanamide and the other was left untreated. The Lymnaea truncatula snails were counted on three different occasions. The results indicated a poor molluscicide efficiency. Body weight gains, anti-Fasciola antibody levels, faecal egg counts, levels of sorbitol dehydrogenase (SDH) and gamma-glutamyl transferase (gamma GT), packed cell volumes, white blood cells and differential leucocyte counts were determined monthly. No statistically significant difference was observed between animals from the two plots regardless of the recorded data. No correlation was found between body weight gains and other biological data. The sampling date had a significant effect on the antibody responses within a same group, and on the enzymatic levels for all groups combined. The forecast results were consistent with the recorded data. Temperature was a major bioclimatic constraint on the transmission of life cycle, and risk of infection occurred mainly in late spring (May/June) and in early September. Current results might be used to issue advice on the need for flukicide treatment of cattle. The indicators of the infection considered alone were useless and it is concluded that herd diagnosis of fasciolosis may rely on the rise of specific antibody levels, possibly associated with an increase in hepatic enzyme activities.

Animals↗

Autoradiographic study on the uptake of (3)H-6-thymidine by Fasciola hepatica.

Autoradiographic study was performed in order to know the distribution of exogenous radioactive substance, (3)H-6-Thymidine, by liver fluke, Fasciola hepatica. The worms were maintained in vitro for 1 hour, at 37 degrees C, in Tyrode solution containing (3)H-6-Thymidine. After the incubation, the worms were sectioned and autoradiographed by applying the techniques of microautoradiography. The black grains derived from labeled substance were highly accumulated in the vitelline duct and vitelline glands. Moderate amount of blackening showed in the subcuticular muscle fibers, testes, ovary, cirrus sac, oral sucker and pharynx. Slightly labeled particles were in the reticular tissue, ventral sucker, intestinal epithelium, prostate, uterus and ova. There can hardly be found the black grains in the cuticle.

Journal Article↗

Fasciola hepatica: partial characterization of circulating antigens.

Antigens present in sera from Fasciola hepatica-infected goats were partially characterized by means of polyacrylamide gel electrophoresis of immunoprecipitates obtained by counterimmunoelectrophoresis. Agar containing the 2 immunoprecipitin lines, agar containing no precipitin lines, a crude extract of F. hepatica, and normal rabbit IgG were assayed. The electrophoretic pattern of 1 precipitin line showed, apart from the light and heavy chains of IgG and other faint bands, 2 prominent polypeptides of about 70 and 85 kDa. The other precipitin line showed a similar pattern, but with the 70-kDa band absent.

Animals↗

Pre-exposure of cattle to drug-abbreviated Fasciola hepatica infections: the effect upon subsequent challenge infection and the early immune response.

In this study we examined whether juvenile liver flukes are capable of stimulating protective immune responses in cattle. Four experimental groups of cattle were studied as follows: group A, a positive control, received a primary infection on day 0 and a secondary infection 28 days later; group B also received two infections but the primary infection was terminated by drug treatment on day 5; group C, received infections on days 0, 5 and 10 which were terminated by drug treatments on days 1, 6 and 11 and then a secondary infection on day 28; group D received an infection only on day 28. Juvenile flukes appear to induce protective responses because: (a) group B animals had significantly lower levels of gamma-GT (P<0.05) than group D; (b) both groups B and C exhibited lower parenchymal phase GLDH levels (P=0.006 and 0.041, respectively); and (c) both groups B and C had lower secondary phase eosinophilia (P=0.002 and 0.02, respectively) than those in group D. Sera taken from groups A-C contained antibodies reacting to a variety of proteins in adult fluke somatic antigen and excretory-secretory preparations, particularly to proteins of 52-60, 68-72 and 82-96 kDa. After secondary challenge the antibody responses of group A to these proteins declined while reactivity to proteins of 28-30 kDa increased. Antibody responses to the 28-30 kDa proteins were not detected in groups B-D until 3 weeks later than those observed in group A. Antibody responses to Fasciola hepatica cathepsin L proteases, which are known to induce protection, were monophasic, of the IgG1 isotype only and were not observed prior to secondary challenge in any of the four groups. In contrast, the response to another protective antigen fraction, a high molecular sized haem protein, was of a mixed IgG1/IgG2 nature and was detected within 14 days of primary infection. However, no significant difference in antibody titres to either protein preparation was observed after the secondary infection when groups B and C were compared to group D.

Animals↗

The Effect of Parasitism by Fasciola hepatica and Muellerius capillaris on the Nerve Ganglia of Lymnaea truncatula

Morphometric and histopathological studies were performed in Lymnaea truncatula experimentally infected by Fasciola hepatica or Muellerius capillaris between Days 30 and 60 postinfection. In the pedal ganglia, snail parasitism had a significant influence on the decrease in length and the increase in width in the M. capillaris group. In the dorsal lobes of cerebral ganglia, snail parasitism had a significant influence on the decrease in lobe width in the F. hepatica group and the increase in width in the M. capillaris group. In the two groups of infected snails, snail parasitism had a significant influence on the decrease in the number of neurons in the pedal ganglia and the dorsal lobes of the cerebral ganglia. The other ganglia and lobes did not demonstrate any significant differences in the size or number of neurons. Infected snails of both groups had multifocal nerve lesions, i.e. (a) dyskariosis with occasionally eccentric nuclei and (b) cell lysis with only cell remnants present.

Journal Article↗

Human distomatosis due to Fasciola hepatica infection in Assam, India.

A seven year old girl in a rural area of Upper Assam was found to be infected with Fasciola hepatica. The girl gave history of eating watercress. Besides the presence of eggs in the stools, her liver was enlarged and tender. Liver function tests revealed hepato-biliary involvement with increase in serum AKP and ALT. Ultrasonography revealed presence of adult fluke in gall bladder, and a marginal thickening of gall bladder wall. However, the echo pattern of her liver parenchyma was normal. The case is reported for its public health significance and is a maiden report from north eastern India.

Child↗