The egg hatch test: A useful tool for albendazole resistance diagnosis in Fasciola hepatica.

In the current study, the egg hatch test (EHT) has been evaluated as an in vitro technique to detect albendazole (ABZ) resistance in Fasciola hepatica. The intra- and inter-assay variations of the EHT were measured by means of the coefficient of variation in different fluke isolates and over time; then, the results of the EHT were compared with the "gold standard" controlled efficacy test, which assesses the in vivo anthelmintic efficacy. The EHT was used later to evaluate the intra-herd variability regarding the level of ABZ resistance in calves infected by the same fluke isolate.

Control of spp. infection by sheep flock owners in Northern Ireland.

Background: To address a lack of information on the control of ovine helminth parasites in Northern Ireland (NI), a number of research projects have been undertaken, dealing with gastrointestinal nematodes, tapeworms and liver fluke. This investigation concerns and concentrates on three aspects of disease: farm management strategies for its control, derived from the results of a Questionnaire; the efficacy of treatment used by farmers, as determined by a coprological survey; and the hatching requirements of eggs, that is, whether prolonged chilling is a pre-requisite for hatching.

Results: A Questionnaire was sent to 252 sheep farmers in NI in March 2012 (covering the years 2009-2012) and replies were received from 228 farmers.

Disruption of egg production by triclabendazole-resistant Fasciola hepatica following treatment with a commercial preparation of myrrh (Mirazid).

An in vitro study has been carried out to monitor changes to the female reproductive system in adult triclabendazole (TCBZ)-resistant Fasciola hepatica following treatment with a commercial preparation of myrrh ("Mirazid"). Flukes were immersed for 6 h and 24 h in myrrh extract at a concentration of 200 µg/ml, then processed for histological and transmission electron microscope (TEM) examination of the uterus, Mehlis' gland, ovary and vitellaria. Egg production had become abnormal at 6 h post-treatment (pt), with the uterine lumen being filled with free vitelline cells and masses of shell protein material; few eggs were present.

Time-course and accumulation of triclabendazole and its metabolites in bile, liver tissues and flukes collected from treated sheep.

The flukicidal compound triclabendazole (TCBZ) has a complex metabolic pattern that includes the systemic presence of its sulphoxide (TCBZ.SO) and sulphone (TCBZ.SO2) metabolites, usually recovered from the bile of treated animals.

Differential expression of liver fluke β-tubulin isotypes at selected life cycle stages.

We have shown that Fasciola hepatica expresses at least six β-tubulins in the adult stage of its life cycle, designated F.hep-β-tub1-6 (Ryan et al., 2008).

An amino acid substitution in Fasciola hepatica P-glycoprotein from triclabendazole-resistant and triclabendazole-susceptible populations.

Control of fasciolosis is threatened by the development of anthelmintic resistance. Enhanced triclabendazole (TCBZ) efflux by ABC transporters such as P-glycoprotein (Pgp) has been implicated in this process. A putative full length cDNA coding for a Pgp expressed in adult Fasciola hepatica has been constructed and used to design a primer set capable of amplifying a region encoding part of the second nucleotide binding domain of Pgp when genomic DNA was used as a template.

Mitochondrial DNA haplotype analysis of liver fluke in bison from Bialowieza Primaeval Forest indicates domestic cattle as the likely source of infection.

We have determined the mitochondrial genotype of liver fluke present in Bison (Bison bonasus) from the herd maintained in the Bialowieza National Park in order to determine the origin of the infection. Our results demonstrated that the infrapopulations present in the bison were genetically diverse and were likely to have been derived from the population present in local cattle. From a consideration of the genetic structure of the liver fluke infrapopulations we conclude that the provision of hay at feeding stations may be implicated in the transmission of this parasite to the bison.

Validity and reliability of GPS for measuring instantaneous velocity during acceleration, deceleration, and constant motion.

In this study, we assessed the validity and reliability of 5 and 10 Hz global positioning systems (GPS) for measuring instantaneous velocity during acceleration, deceleration, and constant velocity while straight-line running. Three participants performed 80 running trials while wearing two GPS units each (5 Hz, V2.0 and 10 Hz, V4.

Reducing the future threat from (liver) fluke: realistic prospect or quixotic fantasy?

The liver fluke remains an economically significant parasite of livestock and is emerging as an important zoonotic infection of humans. The incidence of the disease has increased in the last few years, as a possible consequence of changes to the World's climate. Future predictions suggest that this trend is likely to continue.

Fasciola hepatica: time-dependent disruption of spermatogenesis following in vivo treatment with triclabendazole.

Sheep infected with the Cullompton isolate of Fasciola hepatica were treated with triclabendazole at a concentration of 10 mg/kg at 12 weeks post-infection. Adult flukes were recovered from the liver and, where present, from the gall bladder at 48, 72 and 96 h post-treatment (pt). Gross changes to the spermatogenic cells of the testis were examined by histology and ultrastructural alterations were visualised via transmission electron microscopy.

Comparative proteomic analysis of triclabendazole response in the liver fluke Fasciola hepatica.

Control of Fasciola hepatica infections of livestock in the absence of vaccines depends largely on the chemical triclabendazole (TCBZ) because it is effective against immature and adult parasites. Overdependence on a single drug and improper application is considered a significant factor in increasing global reports of fluke resistant to TCBZ. The mode(s) of action and biological target(s) of TCBZ are not confirmed, delaying detection and the monitoring of early TCBZ resistance.

Liver fluke β-tubulin isotype 2 binds albendazole and is thus a probable target of this drug.

Albendazole is a benzimidazole drug which can be used to treat liver fluke (Fasciola hepatica) infections. Its mode of action is believed to be the inhibition of microtubule formation through binding to β-tubulin. However, F.

Enhancement of the drug susceptibility of a triclabendazole-resistant isolate of Fasciola hepatica using the metabolic inhibitor ketoconazole.

A study has been carried out to investigate whether the action of triclabendazole (TCBZ) is altered by using the metabolic inhibitor, ketoconazole (KTZ) to inhibit the cytochrome P450 (CYP 450) system within Fasciola hepatica. The Oberon TCBZ-resistant and Cullompton TCBZ-susceptible isolates were used for these experiments. The CYP 450 enzyme system was inhibited by a 2 h pre-incubation in KTZ (40 microM).

Potentiation of triclabendazole sulphoxide-induced tegumental disruption by methimazole in a triclabendazole-resistant isolate of Fasciola hepatica.

A study has been carried out to investigate whether the action of triclabendazole (TCBZ) against Fasciola hepatica is altered by inhibition of drug metabolism. The flavin monooxygenase system (FMO) was inhibited using methimazole (MTZ) to see whether a TCBZ-resistant isolate could be made more sensitive to TCBZ action. The Oberon TCBZ-resistant and Cullompton TCBZ-susceptible isolates were used for these experiments.

Binding of serum albumin to the anthelmintic drugs albendazole, triclabendazole and their sulphoxides.

The binding of drugs to plasma proteins--especially serum albumin--is an important factor in controlling the availability and distribution of these drugs. In this study we have investigated the binding of two drugs commonly used to treat liver fluke infections, albendazole (ABZ) and triclabendazole (TCBZ), and their sulphoxide metabolites to bovine serum albumin (BSA). Both ABZ and TCBZ caused shifts in the mobility of BSA in native gel electrophoresis.

Unchanged triclabendazole kinetics after co-administration with ivermectin and methimazole: failure of its therapeutic activity against triclabendazole-resistant liver flukes.

Background: The reduced drug accumulation based on enhanced drug efflux and metabolic capacity, identified in triclabendazole (TCBZ)-resistant Fasciola hepatica may contribute to the development of resistance to TCBZ. The aim of this work was to evaluate the pharmacokinetics and clinical efficacy of TCBZ administered alone or co-administered with ivermectin (IVM, efflux modulator) and methimazole (MTZ, metabolic inhibitor) in TCBZ-resistant F. hepatica-parasitized sheep.

Fasciola hepatica: disruption of spermatogenesis by the fasciolicide compound alpha.

Sheep infected with the triclabendazole-susceptible Cullompton isolate of Fasciola hepatica were dosed with 15 mg/kg of compound alpha at 12 weeks post-infection. Adult flukes were recovered from the bile ducts at 24, 48, and 72 h post-treatment (p.t.

Fasciola hepatica expresses multiple alpha- and beta-tubulin isotypes.

We have identified five alpha-tubulin and six beta-tubulin isotypes that are expressed in adult Fasciola hepatica. Amino acid sequence identities ranged between 72 and 95% for fluke alpha-tubulin and between 65 and 97% for beta-tubulin isotypes. Nucleotide sequence identity ranged between 68-77% and 62-80%, respectively, for their coding sequences.

No difference in 1RM strength and muscle activation during the barbell chest press on a stable and unstable surface.

Exercise or Swiss balls are increasingly being used with conventional resistance exercises. There is little evidence supporting the efficacy of this approach compared to traditional resistance training on a stable surface. Previous studies have shown that force output may be reduced with no change in muscle electromyography (EMG) activity while others have shown increased muscle EMG activity when performing resistance exercises on an unstable surface.

Activity of artemether and OZ78 against triclabendazole-resistant Fasciola hepatica.

Triclabendazole is the drug of choice against Fasciola hepatica infections in humans and animals. However, parasite resistance against triclabendazole is spreading in the veterinary field, and there are no drugs of comparable activity currently available for the treatment and control of fascioliasis. We investigated the efficacy of single oral doses of artemether and OZ78 against adult triclabendazole-resistant F.

Alkalosis increases muscle K+ release, but lowers plasma [K+] and delays fatigue during dynamic forearm exercise.

Alkalosis enhances human exercise performance, and reduces K+ loss in contracting rat muscle. We investigated alkalosis effects on K+ regulation, ionic regulation and fatigue during intense exercise in nine untrained volunteers. Concentric finger flexions were conducted at 75% peak work rate (3 W) until fatigue, under alkalosis (Alk, NaHCO3, 0.

A possible model of benzimidazole binding to beta-tubulin disclosed by invoking an inter-domain movement.

Although it is well established that benzimidazole (BZMs) compounds exert their therapeutic effects through binding to helminth beta-tubulin and thus disrupting microtubule-based processes in the parasites, the precise location of the benzimidazole-binding site on the beta-tubulin molecule has yet to be determined. In the present study, we have used previous experimental data as cues to help identify this site. Firstly, benzimidazole resistance has been correlated with a phenylalanine-to-tyrosine substitution at position 200 of Haemonchus contortus beta-tubulin isotype-I.

Drug resistance in veterinary helminths.

At present, there is no effective alternative to chemical control of parasitic helminths where livestock are grazed intensively. Resistance to anthelmintics has become a major problem in veterinary medicine, and threatens both agricultural income and animal welfare. The molecular and biochemical basis of this resistance is not well understood.

Prolonged exercise to fatigue in humans impairs skeletal muscle Na+-K+-ATPase activity, sarcoplasmic reticulum Ca2+ release, and Ca2+ uptake.

Prolonged exhaustive submaximal exercise in humans induces marked metabolic changes, but little is known about effects on muscle Na+-K+-ATPase activity and sarcoplasmic reticulum Ca2+ regulation. We therefore investigated whether these processes were impaired during cycling exercise at 74.3 +/- 1.