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1
Smith, David. "Fasciola hepatica Kunitz-type inhibitors." Thesis, Queen's University Belfast, 2017. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.728662.
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The aim of this thesis was to characterize Kunitz-type (KT) protease inhibitors expressed by the helminth parasite Fasciola hepatica during infection of the mammalian host. KT inhibitors have traditionally been considered serine protease inhibitors. A P1 residue, typically Lys or Arg, within a reactive loop, determines serine protease inhibition specificity. Recombinant KT inhibitor expression was carried out for the gene identified in F. hepatica (fhktl) that encodes an uncommon P1 Leu residue. Inhibition studies found that FhKT1 did not inhibit serine proteases, but did inhibit cysteine protease, particularly cathepsin L-like cysteine proteases. Molecular modelling predicted that residues P1 Leu15 to P4’ Arg19 of the KT inhibitor interact with the S2 and S2’ pockets of the cysteine protease. Interrogation of the F. hepatica draft genome identified seven KT inhibitors in this parasite, which were found to fall into 5 distinct groups. The fhktl group is made up of three highly similar KT genes, two with a P1 Leu residue (fh ktl.1 and fh k tl.2), but another with a P1 Arg (fh ktl.3). Recombinant FhKT1.3was found to inhibit cysteine proteases, as well as trypsin. Transcriptomic analysis revealed that the fhkt genes are temporally regulated across mammal-associated parasite life-cycle stages, with only the fhktl group expressed at all stages. The fhktl group was also found to be the most highly expressed, as well as the only FhKTs secreted by the parasite. Based on the inhibition specificity of FhKT1 inhibitors, their constituative expression, tissue-specific localization and their presence in parasite secretions, these inhibitors are proposed to be multi-functional, with a primary role in the regulation of F. hepatica and host cathepsin L- like cysteine proteases. Based on the ability of FhKT1.3 to inhibit trypsin, this inhibitor could also function in parasite defence. FhKT1 represents a target at which a novel drug or vaccine could be directed.
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Ayer, Carol Theresa. "Methionine Metabolism in Fasciola Hepatica." PDXScholar, 1990. https://pdxscholar.library.pdx.edu/open_access_etds/3954.
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5'-Deoxy-5'-methylthioadenosine (MTA) is derived from s-adenosylmethionine (AdoMet) during the synthesis of the polyamines spermidine and spermine. Methionine can be regenerated from MTA by one of two mechanisms. In mammalian cells and some microorganisms, MTA is degraded to adenine and 5-methylthioribose-1-phosphate (MTR-1-P) via MTA phosphorylase. In certain other microbes, however, MTA is catabolized in two steps; first to adenine and 5-methylthioribose (MTR) via MTA nucleosidase followed by conversion of MTR to MTR-1-P via MTR kinase.
This study was to demonstrate the presence of MTA nucleosidase or MTA phosphorylase in both redia containing cercariae and adult Fasciola hepatica Linnaeus, 1758. If MTA nucleosidase was present, it was wanted to determine if MTR kinase was also present.
The phosphate-dependent cleaving activity of MTA phosphorylase was demonstrated in the cell-free extracts of adult Fasciola hepatica along with an unidentified MTR metabolizing activity. Redia containing cercariae showed MTA nucleosidase and MTR kinase activity.
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McNair, Alan Thomas. "Molecular cloning of Fasciola hepatica antigens." Thesis, Queen's University Belfast, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335604.
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Chambers, E. L. "Tuberculins of the liver fluke, Fasciola hepatica." Thesis, Queen's University Belfast, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.546025.
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Walker, S. M. "Diversity in the liver fluke, Fasciola hepatica." Thesis, Queen's University Belfast, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426913.
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Santos, Tânia Raquel Martins dos. "Genetic characterization of Portuguese Fasciola hepatica isolates." Master's thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/8689.
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Dissertation presented to obtain the Master Degree in Molecular, Genetics and BiomedicinePart of the results discussed in this dissertation was presented in the following communications: R. Santos, M. Calado, J. Sampaio, C. Ferreira, A. Afonso and S. Belo. Contribution to the genetic characterization of Fasciola hepatica populations in Portugal. XXXVII Portuguese Genetic Conference, Lisbon, Portugal, May 28th-30th 2012 [poster communication] R. Santos, M. Calado, J. Sampaio, C. Ferreira, A. Afonso and S. Belo. Contribution to the genetic characterization of Fasciola hepatica populations in Portugal. Arquivos Portugueses das Ciências Biológicas. Tomo XXXVI (in press)
Fasciola hepatica is a parasitic trematode with debilitating and socio-economically devastating effects. At present near to 600 million animals and 2.4 million people in the entire world suffer from fascioliasis. Genetic characterization is of the utmost importance to an efficient epidemiologic control of helminth infections. In the present study we aimed to provide the first insights into the genetic variability of F. hepatica in Portugal. 47 isolates from different hosts (cattle and sheep) and geographical locations (Beja, Castelo Branco, Coimbra, Évora, Faro, Leiria, Lisboa, Portalegre, Santarém and Setúbal) were analyzed through Random Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR), Restriction Fragment Length Polymorphism (RFLP) and sequencing of NADH dehydrogenase subunit 1 (nad1) gene, cytochrome c oxidase subunit 1 (cox1) gene and Internal Transcribed Spacers (ITS) region. RAPD-PCR and RFLP patterns were similar for all the analyzed samples, despite their host and geographical origin. Nucleotide sequencing revealed low levels of genetic diversity within Portuguese isolates and no direct correlation was observed between haplotype and geographical location or host. Phylogenetic analysis revealed a high similarity within samples from Mediterranean countries, such as Portugal, Spain, Tunisia, Algeria and Egypt, possibly due to livestock import/export trade between these countries. Moreover, Portugal presents a low risk of fascioliasis drug-resistance.
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Ajanusi, Joseph O. "Immunochemistry of Fasciola hepatica in the rat model." Thesis, University of Edinburgh, 1994. http://hdl.handle.net/1842/30081.
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The excretions, secretions and surface components of a parasite are by their nature centrally involved in the host/parasite interaction. Rats, like cattle, are capable of developing resistance to fasciolosis after primary infection and are therefore considered a suitable laboratory model for cattle. The objective of this study was to characterise the excretory/secretory (ES) and surface components of Fasciola hepatica as it develops in the rat, and to identify those components involved in the host/parasite interaction that may have diagnostic and/or protective value. Three trials were conducted during the study in order to produce supplies of rat antiserum which was protective against F. hepatica, Rats were infected with either 10 (first trial) or 20 (second and third trials) F. hepatica metacercariae as information from the literature indicated that these doses were adequate to stimulate the production of protective antibody levels. The rat sera from the three trials were checked for the presence of protective antibodies by passive protection studies. Only in the latter two trials was the level of protection conferred on recipient statistically significant. The probable causes for the lack of significant protection in trial 1 are discussed. The silver stained protein profiles of ES from newly excysted (D0) flukes and one-day old (D1) flukes were characteristic and were similar to each other. The ES of parenchymal 14-day old (D14) and adult (D56) flukes were markedly different from D0 and D1 flukes but similar to each other. The silver stained total ES protein profiles of the developing flukes were very different from the total biosynthetically (35S-methionine) radio-labelled ES protein profiles. Possible reasons for this are discussed. However, as with the total silver stained ES protein profiles there were clear changes in the profiles of the biosynthetically radio-labelled ES as the flukes developed. It is suggested that these differences in the ES products may reflect the changing environment and activities of the flukes. The possible functions of the changing ES products are discussed.
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Koch, Sandra. "Untersuchungen zur Verbreitung von Fasciola hepatica im bayerischen Milchviehbestand." Diss., lmu, 2005. http://nbn-resolving.de/urn:nbn:de:bvb:19-40248.
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McKown, Richard Dwayne. "Localization and partial immunological characterization of Fasciola hepatica Thioredoxin." Texas A&M University, 2004. http://hdl.handle.net/1969.1/1401.
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This study reports the localization and partial characterization of thioredoxin from the parasitic trematode Fasciola hepatica. Snails (Pseudosuccinia columella) were raised in culture and infected with F. hepatica so that Western blotting and immunohistochemical techniques could be utilized to determine the presence of thioredoxin in different stages of the parasites development. The results of these experiments showed that thioredoxin was present in the tegument, gut epithelium, excretory canal epithelium and sperm, of the adult parasite as well as in the tegument and gut of the redia and cercaria intermediate stages. In situ hybridization was used to determine the localization and possible differential mRNA expression of two different F. hepatica thioredoxin isotypes (Fh2020.A and Fh2020.SL) in the adult parasite. The in situ hybridization results showed that both isotypes are expressed in the tegument and gut epithelium. Fh2020.A stains with a greater intensity possibly demonstrating a difference in the amount of expression between the two isotypes.
Recombinant F. hepatica thioredoxin expressed in bacteria using the pMAL Protein Fusion and Expression System was used to test its affects on the production of super oxide anion by murine peritoneal macrophages, bovine monocyte-derived macrophages and bovine whole blood neutrophils, and nitric oxide production by mouse peritoneal macrophages and bovine monocyte-derived macrophages. The results of the cellular assays were not definitive due to the fact that the maltose binding protein (MBP) moiety of the recombinant thioredoxin, when tested alone, increased production of nitric oxide by bovine monocyte-derived macrophages. Consequently, since the MBP could not be effectively separated from the thioredoxin portion of the recombinant, allowing the thioredoxin affects to be tested independently, no true conclusions regarding its affects on the host immune cells tested could be drawn.
This is the first report of the localization of thioredoxin in both the adult F. hepatica as well as in specific intermediate stages of the parasite. These studies demonstrate the possible affects that a protein tag can have on experimental results and demonstrate how such data may be interpreted when a non-cleaved recombinant protein is used in cellular or other assays when compared to native or cleaved recombinant proteins.
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McDougall, Heather C. "Identifying “hidden” antigens in the liver fluke, Fasciola hepatica." Thesis, University of Glasgow, 2012. http://theses.gla.ac.uk/3661/.
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Fasciola hepatica is responsible for substantial economic losses and animal welfare issues within the agricultural sector worldwide. The increasing incidence of fasciolosis, coupled with the emergence of flukicide resistance, makes vaccination an attractive alternative control strategy. Hidden antigens extracted from the gut of blood feeding parasites have proven to be excellent vaccine candidates against haematophagous parasites, most notably Haemonchus contortus and Rhipicephalus (Boophilus) microplus. Here, as a first step towards a prototype liverfluke vaccine an attempt to identify hidden gut antigens in F. hepatica was made. Proteomic analysis on extracts of adult F. hepatica was used to identify molecules exclusively found within the membrane-bound fraction including four proteases; cathepsin B2, legumain-2, a putative lysosomal pro-x-carboxypeptidase precursor and a saposin-like protein. Histological sections of adult F. hepatica were screened with a panel of 21 lectins to identify those with an affinity for glycoproteins on the parasite’s gut and to inform subsequent lectin affinity chromatography. Seven lectins showed affinity for the gut region, with peanut (PNA) and jacalin (JAC) lectins binding to glycoproteins on either the gastrodermal cells or gut lamellae, respectively. PNA and JAC were then used to purify glycoproteins from the crude S3 extract by affinity chromatography. The resultant fractions were separated by SDS-PAGE and the protein profiles analysed by mass spectrometry. The enriched lectin-binding fractions shared a number of proteins but one of note that was exclusively identified in the PNA-binding fraction was a cathepsin D-like aspartyl protease, which had not previously been studied in F. hepatica. The proteolytic activities of three somatic extracts of adult F. hepatica were therefore investigated. The ability of the respective fractions to digest haemoglobin, a potential food source, was measured in the presence/absence of class-specific enzyme inhibitors. These analyses confirmed the presence of cathepsin D-like aspartyl protease activity capable of digesting haemoglobin optimally at pH 2 - 2.5. Further characterisation of the cathepsin D-like aspartyl (FhCatD) protease revealed it to be highly conserved within trematodes, to be localized to the gastrodermis of immature (10 day) and adult fluke, and to be more highly expressed, at the RNA level, in the Newly Excysted Juveniles (NEJ) than adult stages. Western blot analysis of native somatic extracts, enriched lectin-binding fractions and recombinant FhCatD using antisera from naturally infected sheep, showed some recognition of the recombinant FhCatD but did not provide clear evidence that the cathepsin D is strongly antigenic during natural infection.
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Bejestani, Mohammad Reza Salimi Avval. "Epidemiology and immunodiagnosis of Fasciola hepatica infection in cattle." Thesis, University of Liverpool, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400242.
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Barnicoat, B. F. "The anatomy of the nervous system of Fasciola hepatica." Thesis, University of Salford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381581.
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Beesley, Nicola Jane. "Population genetic structure of Fasciola hepatica in Great Britain." Thesis, University of Liverpool, 2016. http://livrepository.liverpool.ac.uk/3001200/.
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The liver fluke, Fasciola hepatica, is a trematode parasite that causes disease of economic and welfare importance to the UK livestock sector. Prevalence of F. hepatica infection in sheep and cattle in the UK is increasing; in part due to changes in climate and farming practice, but compounded by the emergence of resistance to the drug triclabendazole. Adult F. hepatica within the definitive host are hermaphrodite, capable of both self- and cross-fertilisation. There are reports of parasite populations maintained by parthenogenesis. Diploid (2n = 2x = 20) and triploid (2n = 3x = 30) F. hepatica have been reported in the UK, but there is little information to indicate how frequently triploidy occurs. The F. hepatica life cycle is complex requiring a snail intermediate host, Galba truncatula. Clonal expansion of the parasite occurs within the snail followed by release of cercariae which subsequently encyst on pasture. Little is known about the population genetic structure of F. hepatica in the UK, or how the clonal expansion in the snail, the capacity for self-fertilisation, and the potential for aggregation of metacercariae on pasture, influence genetic diversity of F. hepatica populations within the definitive host. Knowledge of the genetic structure of F. hepatica in Great Britain is critical to understanding the level of gene flow within F. hepatica populations and how this impacts on the spread of drug resistance genes. The aim of this thesis was to determine the ploidy and population genetic structure of F. hepatica infecting sheep and cattle in Great Britain, and define how passage of the parasite through the snail intermediate host may influence genetic diversity. To determine ploidy a total of 715 adult parasites were collected from naturally infected sheep and cattle, exceeding the statistically representative sample size of 384 individuals (expected proportion of triploids 50 %; 95 % confidence level; 5 % confidence limits). The ploidy and presence of sperm was determined by aceto-orcein squash. One hundred percent were confirmed as diploid and all contained sperm. A multiplex PCR and capillary electrophoresis approach was validated for a panel of fifteen polymorphic microsatellites to assess the population genetic structure of F. hepatica. Eight of these microsatellites met the criteria for population genetic analyses, and were used to produce a multilocus genotype (MLG) for 950 adult parasites from the livers of 44 naturally infected sheep, and 629 F. hepatica adults from 31 naturally infected cattle livers. The average heterozygosity across all parasites and loci was determined as 0.752 (SD = 0.130), indicating high levels of genetic variation in F. hepatica populations. Of the 1579 samples, 1424 distinct MLGs were observed, which supports high genotypic diversity in the population as a whole. Forty six hosts harboured multiple, genotypically identical parasites, which were shown to have arisen from clonal lineages rather than distinct reproductive events. The FIS value indicates a self-fertilisation rate no higher than 2 %, and the FST value (0.0202) indicates low population structure and high gene flow in the British F. hepatica population. To assess the influence of the snail intermediate host on genetic diversity, MLG profiles were used to address: (i) whether a snail can be infected with, and shed cercariae of, more than one genotype of F. hepatica and (ii) the population structure of F. hepatica within field populations of snails in Great Britain. For experiment (i) 49 G. truncatula, from a colony maintained in the laboratory, were exposed to miracidia of known, but distinct, genotype. Two snails, showed evidence of infection with more than one genotype of F. hepatica, but did not shed cercariae. In experiment (ii) 155 snails, including 52 G. truncatula, were collected from three farms in Scotland and North Wales. None of the snails showed evidence of infection with F. hepatica. The results here show that F. hepatica isolated from British cattle and sheep are diploid. In addition, genetic analysis suggests cross-fertilisation predominates over self-fertilisation and parthenogenesis. The British F. hepatica population shows high genetic diversity within populations, but little genetic differentiation between populations, and is therefore panmictic. Our analyses support high gene flow and identified a proportion of parasites within the definitive host that are genetically identical. These observations suggest that drug resistance genes could spread rapidly in F. hepatica populations.
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Dreyfuss, Gilles. "Contribution a l'etude des emissions cercariennes et de la charge parasitaire post-mortem chez trois especes de limnees infestees par fasciola hepatica linne ou par f. Gigantica cobbold." Limoges, 1994. http://www.theses.fr/1994LIMO305E.
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Cancela, Sehabiague Martín Pablo. "Análise do transcriptoma do estágio invasivo de Fasciola hepatica e sua contribuição na compreensão dos mecanismos moleculares envolvidos no processo de infecção." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/28426.
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Fasciola hepatica é um trematódeo parasita e o agente causador da fasciolose. Esta zoonose causa perdas importantes na produção agropecuária e tem uma crescente incidência na saúde dos seres humanos, principalmente em países em desenvolvimento. Mesmo que existem drogas fasciolicidas, estas não evitam a reinfecção e o surgimento de resistência e, portanto são necessárias novas estratégias de controle. A compreensão dos mecanismos moleculares que envolvem a relação parasito-hospedeiro e os processos fisiológicos associados com o parasitismo são questões importantes no estudo da biologia parasitária. A genômica e transcriptômica de F. hepatica são áreas ainda pouco exploradas com pouca informação disponível do estágio invasivo recém desencistado (NEJ). Neste trabalho foi iniciado o estudo do transcriptoma do NEJ, o primeiro estágio do parasito que interage com o hospedeiro mamífero, A partir da análise de expressed sequences tags (ESTs) do estágio juvenil foram obtidos mais de 500 clusters diferentes. Alguns destes clusters foram identificados exclusivamente no estágio adulto, e outros correspondem a transcritos específicos do filo platelmintos. Estas sequências junto com aquelas presentes em parasitos e ausentes no hospedeiro mamífero representam possíveis alvos para o desenvolvimento de novas drogas e vacinas. A análise comparativa das sequências de F. hepatica com sequências de genomas de outros metazoários foi consistente com o posicionamento basal dos platelmintos na filogenia dos bilatérios. O conteúdo GC e a freqüência de uso de códons e aminoácidos apresentaram diferenças com S. mansoni e semelhanças com outros trematódeos. A anotação funcional mostrou uma representação das diversas funções biológicas entre as proteínas preditas. Além das proteases, enzimas antioxidantes e proteínas do tipo mucina, importantes na relação parasito-hospedeiro, foram identificadas várias outras proteínas envolvidas na expressão gênica, síntese protéica, sinalização celular e enzimas mitocondriais. O conhecimento do repertório de genes expressos pelo estágio infectivo de F. hepatica serve como ponto de partida para revelar os aspectos básicos da biologia deste parasito. A integração dos dados de transcriptômica e proteômica, juntamente com as ferramentas de genômica funcional, posiciona a F. hepatica um modelo interessante para o estudo da biologia dos trematódeos.The common liver fluke Fasciola hepatica is the agent of a zoonose with significant economic consequences in livestock production worldwide, and increasing relevance to human health in developing countries. Although flukicidal drugs are available, re-infection and emerging resistance are demanding new efficient and inexpensive control strategies. Understanding the molecular mechanisms underlying the host-parasite interaction provide relevant clues in this search, while enlightening the physiological adaptations to parasitism. Genomics and transcriptomics are still in their infancy in F. hepatica, with very scarce information available from the invasive newly excysted juveniles (NEJs). Here, we provide an initial glimpse to the transcriptomics of the NEJ, the first stage to interact with the mammalian host. We catalogued more than 500 clusters generated from the analysis of F. hepatica juvenile expressed sequence tags (EST), several of them not detected in the adult stage. A set of putative F. hepatica specific transcripts, and a group of sequences conserved exclusively in flatworms were identified. These novel sequences along with a set of parasite transcripts absent in the host genomes are putative new targets for future antiparasitic drugs or vaccine development. Comparisons of the F. hepatica sequences with other metazoans genomes or EST databases were consistent with the basal positioning of flatworms in the bilaterian phylogeny. Notably, GC content, codon usage and amino acid frequencies are remarkably different in Schistosomes to F.hepatica and other trematodes. Functional annotation of predicted proteins showed a general representation of diverse biological functions. Besides proteases and antioxidant enzymes expected to participate in the early interaction with the host, mucin-like proteins and others involved in gene expression, protein synthesis, cell signaling and mitochondrial enzymes were identified. The knowledge of the genes expressed by the invasive stage of F. hepatica is a starting point to unravel key aspects of this parasite‟s biology. The integration of the emerging transcriptomics, and proteomics data and the advent of functional genomics tools in this organism are positioning F. hepatica as an interesting model for trematode biology.
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SEGALINY, FREDERIC. "Distomatoses hepatobiliaires a fasciola hepatica : a propos d'une douzaine de cas en haute-marne." Reims, 1988. http://www.theses.fr/1988REIMM010.
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Gordon-Gibbs, Danielle Kerry Louise. "Fasciola hepatica infection in sheep : current and novel diagnostic tests." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/15875.
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Fasciola hepatica infections cause morbidity and mortality in sheep and have a significant economic impact on farmers. The commonly used diagnostic tests; faecal egg count (FEC), anti-Fasciola antibody ELISA (AbELISA) and the biochemical assays (measuring GLDH and GGT) all have limitations, particularly in detection of pre-patent infections in sheep. A coproantigen ELISA (cELISA) is reported to detect low burdens of infection from 4 weeks post-challenge (wpc) and to only detect current infection. A faecal PCR has been used for early detection of infection, but is limited by inhibitory factors in faecal samples. Loop-mediated isothermal amplification (LAMP) is more resistant to inhibitory factors and has the potential to be a pen-side assay. Triclabendazole (TCBZ) is the drug of choice to treat immature F. hepatica but there have been increasing reports of TCBZ treatment failure in the UK. Treatment outcome is determined using a FEC reduction test (FECRT). A cELISA reduction test (CRT) has recently been proposed. Within this thesis the cELISA, along with FEC, and where feasible the AbELISA and the use of GLDH and GGT concentrations, are evaluated in (1) an experimental challenge model in sheep, (2) individual naturally exposed sheep, in early infection, pre- and post-treatment situations, (3) groups of naturally exposed sheep, including composite samples, in pre- and post-treatment situations and evaluating the FECRT and CRT, lastly a LAMP assay is developed for the detection of F. hepatica, and evaluated against cELISA, FEC and PCR based detection. Two groups of 6 sheep were challenged with F. hepatica metacercarial cysts. In both studies, AbELISA was first to detect infection (3-4 weeks post-challenge (wpc)), followed by cELISA (3-10 wpc) and then FEC (9-10 wpc). Minor fluctuations were seen in both FEC and cELISA levels over both studies and a transient increase in cELISA levels was seen in the first study at 3-8 wpc. All animals were dosed with TCBZ 2 weeks prior to slaughter. The highest FECR was 37% and all sheep had live fluke present in their livers post-mortem. 27 lambs were sampled monthly between June and November with AbELISA, GLDH, GGT, FEC and cELISA tests performed. GLDH and GGT concentrations were above reference ranges from June. AbELISA detected infection in most animals by September and in all but one animal by November. FEC and cELISA both detected some very early positive results, most likely false-positive results, but the majority of animals became positive in November. Twelve lambs were followed to slaughter and all had low burdens of fluke (≤10). A cross-sectional study was conducted including 36 British farms, comprising 812 and 528 sheep pre- and post-treatment, respectively. Low FEC and cELISA results were seen, with better agreement between the two tests pre- than post-treatment. Disagreements between the two tests were more frequently seen where the FEC detected infection but the cELISA did not. This was true both before and after treatment. 80 animals from 2 Scottish farms were confirmed to be infected with liver fluke and given either a TCBZ or closantel treatment and followed for 56 days. A closantel treatment was given to animals that were still infected at 21 days post-treatment (dpt). The highest FECR and CR of the TCBZ-treated groups was 60.3% and 56.4%, respectively, and the lowest FECR and CR of the closantel-treated groups was 83.7% and 94.9%, respectively. A small proportion of closantel-treated animals maintained a low FEC following treatment. Both the FECRT and CRT indicated treatment outcome from 7 dpt. In a postal survey, 41 sample packs were sent to British farmers, of which 25 farmers participated. Samples from 44 and 36 groups were submitted pre- and post-treatment, respectively. Individual and composite faecal samples from each group were tested by FEC and cELISA. Group mean FECs were low and prevalence of infection on farms did not follow a normal distribution. The composite cELISA was more sensitive than the average cELISA, whilst the opposite was true for FEC. The composite cELISA was less sensitive than the composite FEC in low burden situations. A modified version of the composite CRT showed good agreement with the composite FECRT and appears promising in situations where burden was sufficiently high. A faecal LAMP assay, specific to F. hepatica, was developed and evaluated using samples from one of the groups of 6 experimentally challenged animals described above. FEC, cELISA and PCR testing were also performed and compared to the LAMP results. LAMP first detected infection at 3 wpc, followed by cELISA (7 wpc), FEC (10 wpc) and PCR (13 and 14 wpc). The studies within this thesis (1) confirm that cELISA can detect experimental infection of sheep with F. hepatica later than AbELISA but earlier than FEC, and confirm the TCBZ resistant status of a British isolate (Moredun isolate), (2) demonstrate that in animals naturally exposed to F. hepatica, the cELISA does not have an advantage of earlier detection over FEC and is not as sensitive as FEC in established infections (3) show that the modified CRT and composite CRT appear to give a good indication of treatment outcome from 7 dpt, but is of limited use in flocks with a low burden of infection, and (4) demonstrate that a faecal LAMP can detect F. hepatica infection at 3 wpc.
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Robinson, M. W. "Mechanisms of benzimidazole resistance in the liver fluke, Fasciola hepatica." Thesis, Queen's University Belfast, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273381.
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Graham-Brown, J. J. "Immune responses in dairy cattle naturally exposed to Fasciola hepatica." Thesis, University of Liverpool, 2016. http://livrepository.liverpool.ac.uk/3002735/.
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Fasciola hepatica is a parasitic trematode capable of infecting a range of vertebrate species including livestock and humans. Both clinical disease (fasciolosis) and sub-clinical infections are of major economic and welfare importance in food producing animals. The life cycle of F. hepatica requires an intermediate host, which in the UK is the mud snail Galba truncatula. High levels of moisture and ambient temperatures between 10-30oC provide optimal conditions for the development of both parasite and snail. As a consequence of changing weather patterns, disease prevalence has increased in recent years, whilst an over-reliance on effective anthelmintics to control disease has resulted in the selection of drug resistance within parasite populations. Studies investigating vaccination as a potential method to control F. hepatica in cattle have identified specific components of the vaccine-induced immune response such as IgG2 antibody titre and avidity, which are associated with protection. Conversely, evidence from experimental infections indicate that F. hepatica modulates the host immune system towards a non-protective type-2 response, extending parasite survival within the host. The overall objective of this thesis was to analyse the immune response in calves and adult cattle naturally exposed to, and infected with, F. hepatica. This was achieved firstly through the validation of a herd level diagnostic test to identify infected beef and dairy herds, and secondly by evaluating the type of immune response present in infected animals. The outputs will be valuable in informing vaccine development, since the type of immune response present in naturally infected cattle, will ultimately have implications for how such vaccines are applied in the field. Chapter 3 describes the validation of a composite sample analysis for fluke egg counts. A total of 138 individual samples from 7 commercial beef herds in mid-Wales were sampled. Fluke egg counts were done on individual samples in addition to composite samples composed of ten 5g samples. These data together with individual counts from a further 22 dairy farms (638 individual samples) were fitted to negative binomial distributions at the farm level. These were stochastically re-sampled to generate a range of predicted composite counts from which confidence intervals and test sensitivity were determined. When referred back to the original counts, all composite counts were within the generated confidence intervals, with the lower confidence interval indicating a 95% test sensitivity at ≥0.4 eggs per gram of faeces compared to individual count data. With the exception of lactating dairy cattle, diagnosis of F. hepatica is limited to individual faecal and/or serum sampling. This analysis represents an important development, since a validated composite worm egg count for cattle provides a simple yet effective test for screening groups of animals for infection. In chapter 4, immune responses in naïve dairy heifers (n=42) naturally exposed to F. hepatica were evaluated. Calves on 3 commercial UK dairy farms were sampled monthly over the course of their first grazing season and analysed to determine fluke infection status and parasite specific immune responses. Where infection was present, this was associated with increases in type-2 associated responses, with increases in interleukin-4 production, interleukin-5 transcription and an eosinophilia. A reduction in the type-1 associated cytokine, interferon-γ was also observed over the course of infection. These findings suggest that a natural challenge with F. hepatica induces a non-proliferative type-2 response. This has implications for vaccine development and application, since current evidence suggests that stimulation of additional components such as IgG2 antibody and strong cell mediated responses are required for protection. Chapter 5 describes a study carried out on a commercial dairy farm, characterising the immune responses in adult dairy cattle (n=27) with chronic infections. The effect of treating infected animals with triclabendazole (12mg/kg) on the immune response was also assessed. Both parasite specific and mitogen stimulated interleukin-4 production were positively associated with F. hepatica antibody titres based on linear regression analysis, whilst no such correlation was found with interferon-γ. This suggests that modulation of the immune response towards a type-2 response is a feature in chronic infections. Additionally, increases in the regulatory cytokines Transforming Growth Factor-β and interleukin-10, associated with infection in pre and post treatment groups respectively may indicate that these cytokines play a role in parasite induced immune modulation, which has been described previously in experimentally infected cattle. Overall, these results show that cattle exposed to and infected with F. hepatica under natural grazing conditions develop a type-2 immune response. This has implications for future vaccination programmes, as the presence of immune modulation arising from natural infection suggests any vaccine induced immune response should be fully developed prior to natural exposure to ensure protection. These results also highlight the importance of the impact of fluke infections on the host’s immune system and the need to investigate and better understand the relationship between F. hepatica and other co-infecting pathogens.
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Smith, Daniel Barnaby. "Predicting temporal changes in Fasciola hepatica abundance from climatic variables." Thesis, University of Liverpool, 2016. http://livrepository.liverpool.ac.uk/3004659/.
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Fasciola hepatica is an economically important parasite of sheep and cattle. The life cycle of this parasite includes freeliving stages and an intermediate snail host (Galba truncatula). In the past, several statistical models have been developed to predict how climatic factors, specifically temperature and rainfall, affect parasite abundance. However, these models were built under historic climate conditions, or for a specific geographic region, and are not well suited to predict how the epidemiology of infection might change in situations of global climatic change. The primary objective of the work described in this thesis was to develop a mathematical model of the life cycle of Fasciola hepatica that, for the first time, captures the seasonality of the parasite and can be used to predict parasite abundance under the varying conditions of climate change and alterations in farm management practices. To build the model, experimental studies were conducted to increase the available data on parasite development and survival in the environment. The experimental work focused on the effects of temperature and water availability on parasite eggs and metacercarial development and survival. The survival of parasites at low temperatures suggests that overwintering of parasites on pasture is very possible. The differential equation model developed focused solely on the freeliving stages of F. hepatica and runs on daily temperature and rainfall (rainy day) data. The model was validated against data from published longitudinal studies and passive disease surveillance data. The limited data available to validate this type of model made it impossible to validate the model in a sufficiently robust manner. From the validation studies, it appears that the model is good at predicting the seasonality of the parasite but performs less well at predicting differences in peak abundance between years. The model predicts that, under two different greenhouse gas emissions scenarios, the abundance of F. hepatica will increase dramatically in future, with more than twice the number of metacercariae currently seen between August and October, and significantly more pasture contamination between June and December. The effects of dosing animals at different times of the year was also investigated, Under historic conditions, in the United Kingdom, a single dose of an appropriate helmintic treatment administered to animals in March will not reduce the number of metacercariae seen in the autumn, but a significant reduction results if an appropriate anthelmintic is administered in May. Greater metacercariae pasture contamination predicted under future climate projections will necessitate changes in farm management practices aimed at limiting transmission, which is predicted to occur earlier in the year.
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Villar, Callupe Lena Sharon, and Napuri Lourdes Estefania Sandoval. "Prevalence of fasciola hepatica infection in children from Cajamarca, Perú." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2017. http://hdl.handle.net/10757/621918.
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Objetivo general: Estimar la prevalencia y factores asociados a la infección de Fasciola hepatica por PCR en muestras de heces recogidas de niños escolares del distrito de San Pablo, Cajamarca, Perú.
Objetivos específicos:
- Estimar la prevalencia de infección por Fasciola hepatica por PCR en niños escolares del distrito de San Pablo, según edad, sexo y contacto con ganados.
- Establecer los factores asociados a la infección por Fasciola hepatica por PCR en niños escolares del distrito de San Pablo.
Métodos: Se realizó un estudio transversal prospectivo de abril a junio de 2015 en niños de 5 a 12 años de la Institución Educativa Estatal del nivel primario de Educación Básica Regular del distrito de San Pablo provincia de Cajamarca, Perú. La muestra estuvo constituida por un total de 150 niños de los cuales fueron obtenidas las muestras de heces y se analizaron por reacción en cadena de la polimerasa (PCR) para determinar la infección por Fasciola hepatica.
Resultados: Se detectó ADN de Fasciola hepatica en el 10.67% de muestras de heces, con una prevalencia en niños de 11,54% y niñas de 9,72%. El grupo de edad de 5-8 años (13,64%) mostró un ligero mayor porcentaje de infectados con respecto al grupo edad de 9-12 años (8,33%). No se encontró ninguna diferencia estadística entre un animal específico y los pacientes con muestras positivas para Fasciola hepatica. Los factores asociados a la infección fueron; el consumo de agua de acequia y el consumo de menestra presentando una asociación positiva y negativa, respectivamente.
Conclusiones: La prevalencia de infección por Fasciola hepática en niños escolares hallada en el distrito de San Pablo fue de 10,67%. Con respecto a la presencia de fasciolasis, no se encontró diferencia de acuerdo al género, grupo de edad y contacto con animal. Se determinó que el consumo de agua de acequia predispone a la infección por Fasciola hepática, y que la proporción de niños con esta infección fue menor con el consumo de menestras.
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Wicki, Pascal. "Réactions cellulaires intestinales du bovin après infection par Fasciola hepatica /." [S.l.] : [s.n.], 1991. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
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Boutinet, Catherine. "Réflexions sur une épidémie de distomatose : 8 observations." Bordeaux 2, 2000. http://www.theses.fr/2000BOR2M060.
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Marques, Sandra Marcia Tietz. "Glomerulonefrite na fasciolose bovina e bubalina." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2002. http://hdl.handle.net/10183/5404.
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A fasciolose é uma zoonose parasitária de importância econômica principalmente para ruminantes. O dano causado pela morte dos animais é só uma fração das perdas econômicas, que é produzido pelos estados subclínico e crônico, que se manifesta com redução na produção de carne, leite e lã, condenação de fígados parasitados, infecções secundárias por bactérias, interferências na fertilidade e gastos com tratamento. O envolvimento de complexo antígeno-anticorpo causando reação de hipersensibilidade tipo III, decorrente de parasitoses é bem documentado. Porém não existem relatos do dano renal associado à Fasciola hepatica . Esta tese apresenta a comprovação da hipótese de glomerulonefrite associada à complexos imunes, em bovinos e búfalos naturalmente infectados..Foi necessária a obtenção dos parasitos para a produção de antígenos e de soro hiperimune, e de biópsias renais para a verificação in situ da reação antígeno – anticorpo. Esta tese consta de quatro artigos que descrevem estudos sobre a prevalência de fasciolose em bovinos e búfalos e os diagnósticos histopatológico e imunológico para evidenciação da reação de hipersensibilidade tipo III nos rins dos animais parasitados. O Artigo um descreve a prevalência de fasciolose em 10, 34 % (39) dos 377 fígados bovinos, obtidos de animais de 11 municípios do estado do Rio Grande do Sul. Dos municípios incluídos no estudo, em 63,9 % (7) deles houve o registro do parasito. O Artigo dois relata a prevalência de 20 % (21) de fasciolose hepática em 105 búfalos procedentes do estado do Rio Grande do Sul. Dos 5 municípios incluídos no estudo, em 80 % (4) deles houve o registro do parasito. Por faixa etária, para os búfalos de até 2 anos de idade a prevalência foi de 81 %. Para os animais acima de 2 anos de idade, a prevalência foi de 19 %.
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Chevrier, Soizic. "Epidémiologie de la fasciolose du bétail dans le Sud-Ouest de la France." Paris 5, 1988. http://www.theses.fr/1988PA05P059.
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Fernandez, Jean. "Distomatose a fasciola hepatica : traitement par le praziquantel ; etude sur une serie de 25 cas." Toulouse 3, 1992. http://www.theses.fr/1992TOU31054.
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PAULA, F. M. A. B. "Caracterização morfológica e histoquímica de fígados bovinos com fasciolose crônica." Universidade Federal do Espírito Santo, 2014. http://repositorio.ufes.br/handle/10/7762.
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Previous issue date: 2014-02-21A fasciolose bovina produz danos graves ao fígado e é causada pelo parasito Fasciola hepatica. Objetivou-se caracterizar as alterações morfológicas e histoquímicas do tecido hepático em bovinos com fasciolose crônica, bem como, identificar os focos de metaplasia. Foram coletados 47 fígados de bovinos condenados por fasciolose e 12 fígados normais utilizados para controle, no matadouro frigorífico de Atílio Vivacqua, ES. Foi feita a contagem de parasitos e coleta de cinco fragmentos de cada lobo, direito e esquerdo, dos fígados acometidos pela enfermidade, totalizando 235 amostras por lobo. O grupo controle foram coletados apenas um fragmento por fígado. Todo material foi fixado em formol a 10% e submetido ao processamento histológico e coloração por HE e PAS. Foi feita a análise microscópica com base na distribuição da fibrose em graus 1, 2 e 3 e no tipo e intensidade do infiltrado inflamatório, seguida da avaliação dos focos de metaplasia. A avaliação estatística foi feita pelo método descritivo e pelo teste de Mann-Whitney com 5% de probabilidade. Não foi verificada diferença entre o número de parasitos por lobo hepático, porém o lobo esquerdo apresentou maior intensidade parasitária. A fibrose foi observada em todas as amostras prevalecendo a de grau 1. Houve diferença significativa entre fígados com F. hepatica e fígados normais quanto ao grau de fibrose, tanto para o lobo direito quanto para o esquerdo e entre estes. O infiltrado inflamatório revelou predominância de células mononucleadas de intensidade discreta. Houve diferença entre a intensidade do infiltrado inflamatório entre os lobos direito e esquerdo do fígado. A presença de eosinófilos também foi verificada, porém em menor quantidade. Em relação aos focos de metaplasia observou-se que 53,19% das amostras do lobo direito apresentaram estas 8 alterações enquanto que, no lobo esquerdo, este percentual foi de 57,45%, entretanto, não foram encontradas diferenças significativas entre a ocorrência de metaplasia entre os lobos direito e esquerdo. Foi observada maior prevalência de produção de muco em intensidade discreta e moderada, no entanto, não houve diferença entre a quantidade de muco produzida entre os lobos hepáticos. Conclui-se que a fibrose é alteração mais marcante em fígados cronicamente infectados por F. hepatica sendo mais evidente no lobo hepático esquerdo. O infiltrado inflamatório foi predominantemente mononuclear e discreto e também mais prevalente no lobo esquerdo. Os focos de metaplasia estão presentes nos fígados com fasciolose crônica e possuem diferença na intensidade de muco produzido.
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Ciolkovitch, Alexandre. "Etude sero-epidemiologique de la distomatose a fasciola hepatica en corse." Aix-Marseille 2, 1990. http://www.theses.fr/1990AIX20902.
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Gilbert, Huaynate Jim Tomas. "Prevalencia y evaluación de la carga parasitaria de cerdos criados en los distritos de el Mantaro y San Lorenzo, provincia de Jauja,departamento de Junín." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2015. https://hdl.handle.net/20.500.12672/4610.
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Las parasitosis que afectan a los cerdos se caracterizan por ocasionar pérdidas económicas a los
productores. Los parásitos reducen el índice de conversión alimenticia y disminuyen la
productividad de la crianza de porcinos. El objetivo del presente estudio fue determinar que
parásitos tenían prevalencias mayores al 5% y calcular la carga parasitaria de los mismos en los
distritos de El Mantaro y San Lorenzo. Se recolectaron 257 muestras de heces de cerdo durante
los meses de junio a agosto del 2013. Las muestras fueron evaluadas mediante los métodos de
flotación, sedimentación y McMaster modificado. Se obtuvo una prevalencia total de 22.57%
para Ascaris summ, 73.15% para HTS, 18.68% para Trichuris suis, 41.25% para Metastrongylus
spp. y 12.06% para Fasciola hepatica. La carga promedio hallada fue de 2.62 hpg para Ascaris
summ, 100.04 hpg para HTS, 1.33 hpg para Trichuris suis, 6.07 hpg para Metastrongylus spp. y
0.68 hpg para F. hepatica.
Palabras claves: Porcinos, HTS, Fasciola hepatica, Ascaris summ, Metastrongylus spp.,
Trichuris suis, Valle del Mantaro.--- Parasitic diseases of pigs are characterized by producing economic losses to producers. Parasites reduce feed conversion ratio and decrease productivity of pigs. The aim of this study was to determine which parasites have prevalence rates higher than 5% and calculate the parasitic load of each of the parasites in the districts of the Mantaro and San Lorenzo. Two hundred and fifty seven fecal samples of pig feces were collected during the months of June to August 2013. The samples were evaluated using the following methods: flotation, sedimentation and modified McMaster. Pevalence of Ascaris suum was 22.57 %, 73.15 % for HTS, 18.68 % for Trichuris suis, 41.25 % for Metastrongylus spp and 12.06 % for Fasciola hepatica . The average load was found 2.62 for Ascaris summ EPG, EPG for HTS 100.04, 1.33 for Trichuris suis EPG, EPG for Metastrongylus spp. 6.07 and 0.68 epg for F. hepatica. Keywords: Swine, HTS, Fasciola hepatica, Ascaris summ, Metastrongylus spp., Trichuris suis, Mantaro Valley.
Tesis
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Caseby, R. H. "Aspects of ionic regulation in the liver fluke, Fasciola hepatica L." Thesis, Queen's University Belfast, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333784.
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Thiagarajan, Lalitha. "Factors influencing the interactions between Fasciola hepatica and its intermediate host." Thesis, Queen's University Belfast, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.676711.
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Fasciolosis, a zoonotic infection in humans and livestock, is caused by fasciolid trematodes. The trematode lifecycle requires the infection of a molluscan intermediate host by motile miracidia which hatch from fluke eggs deposited in faeces of definitive host. The transmission of miracidia to snails is considered as the most vulnerable link in their life cycle, and hence has been the focus of considerable interest, in an attempt to reduce the transmission rate. This thesis explores factors involved in interaction between liver fluke miracidia and their snail intermediate host. The species of lymnaeid snails present on farms in Ireland where infected livestock with fasciolosis have been reported, have been identified and their genetic variability and population structure has been determined. The correlation between environmental characteristics and snail prevalence and fluke infection has been assessed (Results I and 11). Host finding and recognition abilities of the Fasciola hepatica miracidia have been studied. Chemotactic ability of the miracidia is found to be comprised and an alternate explanation for successful transmission of the fasciolosis, in which sna'ils were attracted towards the source of miracidia, has been discussed (Results Ill). The swimming patterns of miracidia, from three species of fasciolids, have been determined and analyzed and their responses to physical factors, such as, temperature and salt concentrations have been noted (Results IV). Responses to two anthelmintic drugs by the liver fluke miracidia have been studied, leading to the development of a new method of testing the efficiency of drugs on trematodes (Results IV). Immunofluorescent light microscopy, scanning and transmission electron microscopy have been used to study the structures involved in the movement of miracidia (Result V). The information derived from the experimental work in this thesis may help find an effective way to disrupt the snail-trematode interaction and thus prevent the transmission of fasciolosis
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Zinsser, Veronika Lucille Anne. "Biochemical characterization of metabolic enzymes from the liver fluke, Fasciola hepatica." Thesis, Queen's University Belfast, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.675417.
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The common liver fluke, Fasciola hepatica, infects both human and animals causing fasciolosis. The World Health Organization estimates that ~2 .4 million people are infected with fasciolosis and another 180 million are at risk of being infected. It is thought to be the most economically damaging livestock disease compared to any other helminth parasite diseases. An important influence on the biochemistry of the parasite is its changing environment throughout its life cycle, requiring its metabolism to move from aerobic to anaerobic as it matures. The fluke's metabolic adaptations permit energy extraction to occur even in an anaerobic environment using a variation on the CA cycle. is thesis explores five enzymes from Fasciola hepatica concerned witl~ energy production - citrate synthase (FhCS), triose-phosphate isomerase (FhTPI), glyceraldehyde-3-phosphate dehydrogenase (FhG3PDH), and galactokinase (FhGALK), and UDP-galactose 4-epimerase (FhGALE). FhCS was cloned and sequenced; however, expression and purification proved difficult. Nevertheless, extracts from bacterial cells expressing the protein showed additional CS activity. FhTPI, FhG3PDH, FhGALK and FhGALE have been successfully cloned, sequenced, expressed, purified and characterized. TPI from the related helminth, Schistosoma mansoni, (SmTPI) was also characterised in a comparative study. FhTPI and SmTPI show remarkable thermal and proteolytic stability. FhG3PDH shows increased stability in the presences of substrate; furthermore the addition of ligands results in the change of the enzymes conformation and oligomierc state. FhGALK shows similarity to both galactokinase and N-acetylgalactoasmine from other organisms; however no activity was displayed with either of heir substrates. FhGALE has been characterized kinetically; early inhibition studies have identified two compounds (found through an in silico screen) which show selectivity for the fluke enzyme over the human one. these biochemical studies, combined with molecular modelling, were used to assess whether these metabolic enzymes from F. hepatica may make plausible targets for the development of novel anthelmintics.
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Keller, Charlotte. "Untersuchungen zum Nachweis von Fasciola hepatica-Infektionen bei natürlich infizierten Rindern /." [S.l : s.n.], 1985. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
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Banha, Pedro Miguel Batista. "Contribuição para conhecimento do parasitismo por Fasciola hepatica no Baixo Alentejo." Master's thesis, Universidade de Évora, 2016. http://hdl.handle.net/10174/17755.
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No presente trabalho são descritas as atividades desenvolvidas durante o estágio curricular do Mestrado Integrado em Medicina Veterinária da Universidade de Évora. Na primeira parte é apresentada a descrição das atividades acompanhadas nas áreas de sanidade, profilaxia, clínica médica e clínica cirúrgica de espécies pecuárias. Na segunda parte do relatório é apresentada uma revisão bibliográfica sobre o parasitismo por Fasciola hepática em pequenos ruminantes. Por fim, foi realizado um estudo caso sobre fasciolose em pequenos ruminantes no Baixo Alentejo, que consistiu no estudo de 15 animais de cada efetivo, de um total de 17 explorações de ovinos e três de caprinos. Foram pesquisados ovos de F. hepatica, recorrendo a método coprológico qualitativo de sedimentação, não se tendo encontrado ovos de trematodes em qualquer amostra de fezes observada, ainda que em três explorações ocorreu serologia positiva. Ainda que o parasitismo possa estar presente nas explorações estudadas, atendendo à sua boa condição corporal, não será muito significativo; Abstract:
Contribution to the Knowledge of Parasitism by Fasciola hepatica in Baixo Alentejo
This report aims to describe the developed activities during the internship integrated on the master degree in veterinary medicine at the University of Évora. Firstly are described the observed actions in the areas of diseases control programs, medical and surgical activities in livestock. The following part of this report consists on a literature review of Fasciola hepatica, focusing of fasciolosis in small ruminants. Lastly, was conducted a case study of fasciolosis in small ruminants in the Baixo Alentejo region, in which the study of 15 animals per livestock, in a total of 17 farms of sheep and three of goats. There were searched eggs of F. hepatica, through a coprological method of sedimentation, not eggs were found in any sample of observed feces, even do three flocks were serologicaly positive. Although parasitism could be present in the given area, it dimension, given to the good body conditions of the animals, would not be very significant.
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Sabourin, Emeline. "Dynamique de la fasciolose dans un système fortement anthropisé : la Camargue." Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTG047/document.
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L’émergence et la ré-émergence de maladies que nous connaissons depuis ces cents dernières années représentent une véritable crise sanitaire en grande partie due aux perturbations anthropiques qui modifient les écosystèmes et les interactions entre les parasites et leurs hôtes. La prévention et le contrôle des maladies infectieuses nécessitent la compréhension de leur dynamique dans l’ensemble des compartiments dans lesquels elles circulent. Parmi ces maladies, la fasciolose est une maladie particulièrement sensible aux changements liés à l’Homme. Cette zoonose causée par le parasite Fasciola hepatica, est communément reconnue comme un problème vétérinaire, mais aussi de santé publique, dans certaines régions du monde. Notre étude vise à comprendre la dynamique de circulation et les risques d'émergence de la fasciolose dans un contexte de forte anthropisation. Il s'agit (1) d'étudier la dynamique de l’hôte intermédiaire, un mollusque de la famille des lymnaieidae. (2) de comprendre la dynamique et la diversité du parasite entre et au sein de ses différents compartiments hôtes définitifs. Ces travaux ont été menés sur le territoire camarguais sur le domaine de la Tour du Valat, nous permettant d’avoir accès aux hôtes définitifs, sauvages (ragondins et sangliers), domestiques (taureaux traités et non traités) et à l’hôte intermédiaire, Galba truncatula appelé communément limnée tronquée. Dans un premier temps, nous avons caractérisé la végétation des habitats favorables à la présence du mollusque et nous avons trouvé que les mares semblaient être des zones présentant un risque plus important que les canaux d’irrigation pour la transmission de la fasciolose. Puis, nous nous sommes intéressée à l’influence des habitats sur la dynamique de G. truncatula par des approches de génétique des populations. Nos résultats ont permis de montrer que la permanence des habitats et la connectivité influencent le mode de reproduction, la structuration des populations et la dispersion des limnées en Camargue. Dans un second temps, nous avons étudié la dynamique et la circulation du parasite au sein du compartiment hôte définitif. Nos résultats de la génétique des populations du parasite chez les hôtes définitifs, nous ont indiqué qu’il existait sur notre site d’étude plusieurs sites de transmission constituant un seul grand foyer global. Par ailleurs, l’étude de la circulation du parasite entre les hôtes définitifs suggère le rôle des sangliers dans la dispersion de la maladie et le rôle des ragondins dans le maintien du cycle de la fasciolose. Cette étude met en évidence l’intérêt de mener des études à long terme et l’importance de prendre en compte tous les compartiments impliqués pour comprendre l’épidémiologie d’une maladie. Elle souligne également le rôle des activités humaines et de l’écosystème dans la dynamique de la fasciolose. Le but final de cette étude est de proposer une gestion intégrée adaptée au contexte camarguais afin de limiter l’impact sanitaire de la fasciolose mais aussi des autres maladies liées à l’élevage dans cette régionThe emergence and re-emergence of diseases encountered over the last hundred years represent a real health crisis largely due to anthropic disturbances that affect the ecosystems as well as the interactions between parasites and hosts. The prevention and control of emerging infectious diseases require an in-depth understanding of their dynamics in all the compartments in which they occur. Among these diseases, Fasciolosis is particularly sensitive to human related changes. This zoonosis caused by the parasite Fasciola hepatica, is commonly recognized as a veterinary problem and major public health issue in certain countries. Our study aims to understand the circulation dynamics and risks of fasciolosis emergence in a context of high anthropization. Our objective is (1) to study the dynamics of the intermediate host, a mollusc of the lymnaieidae family. (2) to understand the dynamics and diversity of the parasite between and within its different definitive host compartments. This work was carried out in the Camargue in the Tour du Valat estate, allowing us to have access to the definitive hosts, wild (nutria and wild boars), domestic (treated and untreated bulls) and the intermediate host, Galba truncatula. First, we characterized the habitats that are favorable to the intermediate host G. truncatula, presence in Camargue and we found that ponds appear to be areas of higher risk than irrigation channels for fasciolosis transmission. Then, we became interested in the influence of habitats on the dynamics of G. truncatula through population genetics approaches, our results showed that habitat permanence and connectivity influence the reproduction mode, population structure and dispersal of G. truncatula in the Camargue. In a second step, we studied the dynamics and circulation of the parasite within the definitive host compartment. Our results of the population genetic analyses of definitive hosts indicated that there were several transmission sites on our study area that constituted a single large global outbreak. In addition, the study of the circulation of the parasite between wildlife and domestic animals suggests the role of wild boars in the spread of the disease and the role of nutrias in maintaining the fasciolosis cycle. Our work highlights the value of long term studies and the importance of taking into account all the compartments involved to understand the epidemiology of a disease. They also emphasize the role of human activities and ecosystem in the dynamics of fasciolosis. The ultimate goal of this study is to propose integrated management measures adapted to the Camargue context in order to limit the health impact of fasciolosis and other livestock diseases in the region
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Sadoun, Franck. "Epidémiologie, diagnostic et traitement de la distomatose à Fasciola hépatica." Bordeaux 2, 1991. http://www.theses.fr/1991BOR2M083.
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Thakur, Sameer. "Application of molecular diagnostic methods for the detection and quantification of Fasciola hepatica infection in cattle faecal samples." Thesis, Federation University Australia, 2020. http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/176666.
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Fasciola hepatica, commonly known as liver fluke, is a globally distributed trematode causing significant production losses in ruminant livestock. Due to reduced drug efficacy, there is a need for appropriate diagnostic tools, which would allow alternative management practices to be developed and minimize economic losses. The traditional ‘gold standard’ method for diagnosis, faecal egg count (FEC), is associated with low sensitivity when diagnosing F. hepatica infection in livestock using faecal samples. The present study aimed to compare the sensitivity and specificity of the molecular diagnostic methods [conventional PCR (cPCR), Loop Mediated Isothermal Amplification (LAMP) and quantitative real time PCR (qPCR)] with the conventional diagnostic method FEC, for detecting F. hepatica infection using cattle faecal samples. Faecal samples were collected from 94 experimentally-infected cattle 12 weeks post infection and 40 faecal samples were collected from cattle with no previous history of F. hepatica infection, as a comparative control. The sensitivity of conventional PCR, LAMP and qPCR was 86.2%, 87.2% and 96.8% respectively, which was similar to the faecal egg count (97.9%). While the specificity of all the molecular methods were 97.5%, and for FEC the specificity was 100%. The potential advantage of these molecular diagnostic tests, with further development, suggest they may be a viable alternative diagnostic test when compared to FEC. In addition, a pilot study was conducted to evaluate the potential use of a commercial snail trap in catching and detecting the intermediate host of F. hepatica in irrigated farmland, as an alternative management strategy. However, under the parameters tested in these experiments, the use of commercial snail traps to catch the intermediate host of F. hepatica from farm irrigation channels was shown to be ineffective.Masters by Research
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Wells, K. R. "Ion channels and control of motility in the liver fluke fasciola hepatica." Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492164.
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Throughout the course of this Thesis, a range of different, yet parallel, experimental techniques were employed to investigate ion channels and control of motility in the liver fluke. In the first experimental study, voltage-gated potassium channels and control of motility were investigated using isometric tension recording studies. All of the classical potassium channel blockers employed had some form of excitatory effect on spontaneous contractions of the liver fluke. Of the more selective blockers tested, only the Kv I subfamily blocker, correolide, and the Kv 1.4 subtype blockers, zero potassium solution and riluzole, had any affect on spontaneous contractions. The results suggest a functional role for voltage-gated potassium channels in the contractility of fluke body wall, and imply that the Kv1.4 subtype may be involved. In the second experimental study, calmodulin and control of motility in the liver fluke was investigated. Immunohistochemical studies showed calmodulin immunostaining in all three ofthe welldistinguished muscle systems ofthe fluke, in addition to the vitelline cells and neural tissue. However, none of the calmodulin or myosin light chain kinase inhibitors had any effect on the spontaneous contractions of the fluke body muscle strips in isometric tension recordings. The results suggest that calmodulin plays a role in muscle systems as well as vitelline cells and neural tissue however its involvement in contractility is still not clear. The final experimental study investigated voltage-gated calcium channels and calcium store release channels and control of motility in the fluke. Findings from isometric tension recordings revealed that all of the mammalian L-type calcium channel blockers effected spontaneous contractions of the fluke body muscle, suggesting that L-type calcium channels play functional roles in fluke contractility and have similarity to mammalian L-type calcium channels. Such findings were supported by sequencing of part of a fluke (1.1 subunit, which was found to share 75% identity to the corresponding region of a channel subunit in Schistosoma mansoni, and this protein most closely resembles an L-type calcium channel in vertebrates.
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Prowse, Rhoda 1975. "The molecular basis for the resistance of Fasciola hepatica to cellular cytotoxicity." Monash University, Dept. of Biochemistry and Molecular Biology, 2003. http://arrow.monash.edu.au/hdl/1959.1/7714.
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Campos, Elida Geralda. "Cytochrome c peroxidase in trematodes : studies in Schistosoma mansoni and Fasciola hepatica." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=37700.
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Schistosoma mansoni and Fasciola hepatica are parasitic trematodes which contain cytochrome c peroxidase (CcP) in their mitochondria, an enzyme that is absent in mammalian tissues. CcP reduces hydrogen peroxide to H2O using cytochrome c as the electron donor. Both parasites are catalase deficient; thus, cytochrome c peroxidase and glutathione peroxidase are the enzymes involved in the detoxification of H2O 2 in these organisms. The enzymatic activity of these two peroxidases may enable S. mansoni and F. hepatica to survive oxidative stress. The main objective of this study was to characterize cytochrome c peroxidase from S. mansoni and F. hepatica . Kinetic studies of this enzyme in crude homogenate and isolated mitochondria of S. mansoni were initially performed, followed by purification studies from S. mansoni and F. hepatica . The parasite enzyme has affinity for horse heart and yeast cytochrome c and it is inhibited by sodium azide and potassium cyanide. CcP was purified close to homogeneity and identified as a protein containing heme. The antioxidant capability of F. hepatica CcP was tested in vitro , demonstrating that CcP protected the sugar deoxyribose from oxidative degradation. Exposure of adult worms to H2O2 caused a decrease in S. mansoni CcP activity in vivo. An attempt was made to clone the S. mansoni CcP gene. The experiments did not result in the cloning of the CcP gene, but led to the identification and cloning of another protein, a component of a cytosolic chaperonin, t-complex polypeptide one (TCP-1). TCP-1 from S. mansoni is highly homologous to TCP-1 proteins from different organisms including, Chinese hamster, human, Drosophila and yeast and carries ATP binding amino acid motifs indicating that it has ATPase activity.
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Keegan, Paul Stephen. "Immune responses associated with Fasciola hepatica infection and vaccination in the rat." Thesis, Queen's University Belfast, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282193.
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Anderson, Shona M. L. "Biochemical and immunological studies of surface components of Fasciola hepatica throughout development." Thesis, Queen's University Belfast, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335984.
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Tormey, Sinead M. "A peptide-responsive protein from Fasciola hepatica : isolation, localisation and molecular studies." Thesis, Queen's University Belfast, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398173.
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Hoyle, Deborah Val. "Bovine immune responses to Fasciola hepatica during the early stages of infection." Thesis, University of Edinburgh, 2000. http://hdl.handle.net/1842/29809.
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This study was designed to investigate the effect that pre-exposure of cattle to 1-2 and 5-6 day old flukes had upon subsequent challenge infection, when compared to naive and chronically infected animals. Infection parameters, together with peripheral and local cellular and antibody responses to various F. hepatica protein preparations were investigated. A primary exposure to 5-6 day old flukes, terminated by triclabendazole treatment, was found to reduce the degree of liver damage and eosinophilia experienced after a challenge infection. Lower levels of the enzymes gamma-glutamyl transferase and glutamate dehydrogenase were detected in sera, compared to those in naive animals (P < 0.05). Eosinophilia was also reduced (P < 0.01), as was egg out-put in the faeces during the early pre-patent period (P < 0.05). Calves that were pre-exposed to 1-2 day old flukes showed no significant differences in the levels of these parameters, when compared to their naive counterparts. Sera taken prior to the secondary challenge from pre-exposed animals and those receiving an unterminated primary infection recognised a variety of proteins in Western blots of whole somatic adult antigen (WFA) and excretory-secretory (ES) preparations. The IgG1 antibody response to protein bands of 96-82, 76-68 and 60-52 kDa predominated. After secondary challenge the response of the chronically infected animals to these protein species was reduced and extremely strong recognition of bands in the region 30-28 kDa was noted. Pre-exposed animals maintained the response to the higher weight bands, showing a similar, but initially stronger recognition pattern, to that of naive challenged animals. The lower weight protein bands were not detected in these groups until much later. The IgG1/IgG2 isotype antibody response to purified cathepsin and haem-containing high molecular weight fractions were also examined by ELISA. A monophasic, IgG1 response was seen to the cathepsin fraction, which occurred later during the infection process and was not seen prior to secondary challenge in any of the four groups. A mixed IgG1/IgG2 antibody response to the haem fraction was seen within 14 days of primary infection.
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Jemli, Mohamed Habib. "Fasciolose ovine à Fasciola hepatica : contribution à son étude immunologique et biochimique." Toulouse, INPT, 1991. http://www.theses.fr/1991INPT015A.
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L'auteur etudie la fasciolose a fasciola hepatica chez le mouton, dans le double but de mieux connaitre la physiopathologie de la maladie et d'obtenir des moyens de diagnostic precoces et fiables. Apres un rappel concernant la maladie et ses consequences pathologiques et immunitaires, l'auteur presente les methodes d'etude puis les resultats obtenus chez des moutons infestes experimentalement par 200 metacercaires de grande douve en infestation unique. Il rapporte les perturbations immunologiques et biochimiques observees au cours de cette infestation, en remarquant surtout une augmentation importante dans le sang du nombre d'eosinophiles et des activites enzymatiques de la gldh et de la ggt. Leurs evolutions apres l'infestation refletent une atteinte hepatique sevissant entre deux phases successives (atteinte du parenchyme puis atteinte des canaux biliaires). Quelques enzymes tissulaires hepatiques (p-450 et les n-demethylases) ont ete aussi perturbes. Le traitement fasciolicide, par du triclabendazole, est efficace et permet la normalisation, en quelques semaines, des valeurs de parametres sanguins. Quatre reactions serologiques (elisa, immunofluorescence indirecte, hemagglutination passive et double diffusion sur gelose) sont comparees au cours de l'infestation. L'elisa s'est avere le meilleur moyen pour realiser des depistages de groupe ou lors d'enquetes epidemiologiques. L'hap est plus adaptee, pour etablir un diagnostic de la fasciolose de cas isoles. Une application sur le terrain, evoquant les caracteristiques epidemiologiques de la fasciolose ovine dans une region en tunisie, termine ce travail
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Sánchez, Di Maggio Lucía. "Fasciola hepatica : estudo proteômico e caracterização de proteínas relevantes na relação parasito-hospedeiro." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/180738.
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Fasciola hepatica é o parasito causador da fasciolose, doença transmitida através dos alimentos, que afeta a produção pecuária e a saúde humana. Embora a doença seja tratada com anti-helmínticos, as possibilidades de reinfecção e o desenvolvimento de resistência ao triclabendazol exigem novas estratégias de controle. Os produtos de excreção/secreção liberados pelo parasito durante a infecção auxiliam a sobrevivência do parasito, protegendo-o das respostas do hospedeiro, permitindo sua sobrevivência durante um longo período no hospedeiro vertebrado e a finalização do ciclo larval no hospedeiro intermediário. Este trabalho teve como objetivo gerar uma análise proteômica dos estágios intra-mamífero, adulto e NEJ (juvenil recentemente desencistado), de F. hepatica. Até o momento, os dados gerados representam o maior número de proteínas identificadas para este parasito. A classificação funcional revelou a presença de proteínas envolvidas em diferentes processos biológicos, muitos dos quais representam achados originais para este organismo. Além disso, os padrões de infecção dos parasitos são frequentemente ligados ao comportamento do hospedeiro intermediário, o qual pode desempenhar um papel na distribuição e acumulação dos parasitos. Os dois proteomas analisados neste trabalho possuem diferenças em abundância de proteínas individuais e entre as categorias funcionais. Estas diferenças podem ser causadas pelas características do ciclo biológico do parasito em cada hospedeiro (duração do ciclo de vida, quantidade de cercárias geradas, durabilidade das metacercárias, competição com outros parasitos), aspectos biológicos (como idade ou espécie) ou variações ambientais (temperatura, umidade, estação). A compreensão dos mecanismos moleculares subjacentes à interação com os hospedeiros intermediário e definitivo pode fornecer dados que auxiliem a busca de novos alvos no diagnóstico e controle da fasciolose.Fasciola hepatica is the agent of fasciolosis, a foodborne zoonosis that affects livestock production and human health. Although flukicidal drugs are available, re-infection and expanding resistance to triclabendazole demand new control strategies. Parasite compounds released during infection, known as excretory/secretory products, mediate parasite survival within the host. ESP are thought to protect parasites from host responses, allowing them to survive for a long period in the vertebrate host and complete their larval cycle in the intermediate host. This work provides in-depth proteomic analysis of F. hepatica intra-mammalian stages, adult and NEJ (newly existed juvenile), and represents the largest number of proteins identified to date for this parasite. Functional classification revealed the presence of proteins involved in different biological processes, many of which represent original findings for this organism and are can be vital for parasite survival within the host. In addition, infection patterns of parasites are often tied to host behavior, and intermediate host behavior can play a role in shaping the distribution and accumulation of parasites. The two proteomes analyzed here have differences in protein abundance, categories and individual proteins. The differences found here could be due to differences in the biological cycle of the parasite in the host (as duration of the life cycle, amount of cercariae generated, durability of metacercariae, competition with other parasites), biological aspects (as age or species) or environmental variabilities (as temperature, humidity, season). Understanding the molecular mechanisms underlying the complex interaction with the intermediate and definitive host could provide relevant clues, aiding the search for novel targets in diagnosis and control of fasciolosis.
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Bostelmann, Silvia Cristina Werle. "Estudo histopatológico comparativo em fígados de bovinos (Bos taurus L. e Bos indicus L.), bubalinos (Bubalus bubalis L.) e ovinos (Ovis aries L.) infectados por Fasciola hepatica (Linnaeus, 1758)." reponame:Repositório Institucional da UFPR, 2013. http://hdl.handle.net/1884/31833.
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Este trabalho foi realizado com o objetivo de melhor identificar e estudar comparativamente as lesões histológicas do fígado decorrente da fasciolose hepática em três espécies de animais domésticos. Foram examinados fígados infectados por Fasciola hepatica de bovinos e bubalinos provenientes de matadouros e frigoríficos oficialmente inspecionados no Estado do Paraná e fígados de ovinos de propriedades particulares, onde o abate era realizado no local. O material foi processado pela técnica de rotina para histopatologia. As colorações utilizadas foram Hematoxilina-Eosina, Tricrômico de Schorr, Tricrômico de Mallory e Azul de Toluidina. As principais lesões observadas foram cortes de parasitas em ductos biliares, fibrose portal, hiperplasia de ducto biliar, fibrose de parede de ducto biliar e infiltração por linfócitos, plasmócitos, eosinófilos e neutrófilos. Considerando os resultados obtidos, conclui-se que a fasciolose em bovinos e bubalinos se trata de uma fasciolose crônica, principalmente devido a idade de abate ser maior nessas espécies. Nos ovinos o predomínio de eosinófilos caracteriza fase inicial de fasciolose crônica, sendo a idade de abate dos mesmos inferior as outras espécies
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Braga, Fábio Ribeiro. "Ação in vitro de fungos das espécies Duddingtonia flagrans, Monacrosporium sinense e Pochonia chlamydosporia sobre ovos de Fasciola hepatica e Schistosoma mansoni." Universidade Federal de Viçosa, 2008. http://locus.ufv.br/handle/123456789/4943.
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The in vitro effects of four isolates of the nematophagous fungi Duddingtonia flagrans (AC001), Monacrosporium sinense (SF53) and Pochonia chlamydosporia (VC1 and VC4) on eggs of Fasciola hepatica and Schistosoma mansoni was evaluated in two assays (A and B). Eggs of F. hepatica (assay A) and S. mansoni (assay B) were incubated in Petri dishes with 2% water-agar inoculated with the grown fungal isolates and a control without fungus. After seven, 14 and 21 days post- inoculation, one hundred eggs were removed and classified according to the following parameters: type 1, lytic effect without morphological damage to eggshell; type 2, lytic effect with morphological alteration of embryo and eggshell; and type 3, lytic effect with morphological alteration of embryo and eggshell, with hyphal penetration and internal egg colonization. In assay A, D. flagrans (AC001) and M. sinense (SF53) showed results only for type-1 effect on F. hepatica eggs, but with no significant difference (p>0.01) between them. P. chlamydosporia (VC1 and VC4) showed percentage results for ovicidal activity of type-1, -2 and -3 effects on F. hepatica eggs, with type-3 effect of 12.8% (VC1) and 16.5% (VC4); 14.4% (VC1) and 18.7% (VC4), 20.1% (VC1) and 21.5% (VC4) at seven, 14 and 21 days respectively. At the end of assay A no difference was found in the action of VC1 and VC4 for type-1, -2 and -3 effects over the three studied periods. In assay B, D. flagrans (AC001) and M. sinense (SF53) showed percentage results only for type 1 effect on S. mansoni eggs, with no significant difference (p>0.01) between them. P. chlamydosporia showed ovicidal activity on S. mansoni eggs with percentage results for type-1, -2 and -3 effects showing type 3 effect of: 26.6% (VC1) and 17.2% (VC4); 25.6% (VC1) and 22.6% (VC4); 26.3% (VC1) and 23.0% (VC4) at seven, 14 and 21 days respectively. At the end of the assay B, no difference was found in the action between the isolates VC1 and VC4 for type-1, -2 and -3 effects as well. The results of the A and B in vitro assays showed that P. chlamydosporia (VC1 and VC4) negatively affected F. hepatica and S. mansoni eggs and can therefore be used as biological control agent for these helminths.
Avaliou-se, em dois ensaios experimentais (A e B), a ação in vitro de quatro isolados de fungos nematófagos dos gêneros Duddingtonia flagrans (AC001), Monacrosporium sinense (SF53) e Pochonia chlamydosporia (VC1 e VC4) sobre ovos de Fasciola hepatica e Schistosoma mansoni. Ovos de F. hepatica (ensaio A) e ovos de S. mansoni (ensaio B) foram vertidos em placas de Petri com ágar-água 2% com os isolados fúngicos crescidos, e em placas de Petri sem fungo como controle. Ao completarem sete, 14 e 21 dias, aproximadamente cem ovos foram removidos e classificados de acordo com os seguintes parâmetros: efeito do tipo 1, efeito lítico sem prejuízo morfológico à casca do ovo; efeito do tipo 2, efeito lítico com alteração morfológica da casca e embrião; e efeito do tipo 3, efeito lítico com alteração morfológica do embrião e da casca, além de penetração de hifas e colonização interna do ovo. No ensaio A, os fungos D. flagrans (AC001) e M. sinense (SF53) apresentaram resultados percentuais somente para o efeito do tipo 1 sobre os ovos de F. hepatica, porém sem apresentar diferença significativa (p>0,01) entre eles. O fungo P. chlamydosporia (VC1 e VC4) demonstrou resultados percentuais de atividade ovicida para os efeitos dos tipos 1, 2 e 3 sobre os ovos de F. hepatica, com efeito do tipo 3 de 12,8% (VC1) e 16,5% (VC4); 14,4% (VC1) e 18,7% (VC4), 20,2% (VC1) e 21,5% (VC4), respectivamente aos sete, 14 e 21 dias. Ao final do ensaio experimental A, não foi observada diferença na ação de VC1 e VC4 para os efeitos dos tipos 1, 2 e 3 ao longo dos três períodos estudados. No ensaio experimental B, os fungos D. flagrans (AC001) e M. sinense (SF53) apresentaram somente resultados percentuais para o efeito do tipo 1 sobre os ovos de S. mansoni, sem contudo apresentar diferença significativa (p>0,01) entre eles. P. chlamydosporia demonstrou atividade ovicida sobre ovos de S. mansoni com resultados percentuais para os efeitos dos tipos 1, 2 e 3 apresentando um efeito do tipo 3 de 26,6% (VC1) e 17,2% (VC4); 25,6% (VC1) e 22,6% (VC4); 26,3% (VC1) e 23,0% (VC4) respectivamente aos sete, 14 e 21 dias. Contudo ao final do ensaio experimental B, também não foi observada diferença na ação entre os isolados VC1 e VC4 para os efeitos dos tipos 1, 2 e 3. Os resultados dos ensaios experimentais in vitro A e B demonstraram que P. chlamydosporia (VC1 e VC4) influenciou de forma negativa os ovos de F. hepatica e S. mansoni, e assim pode ser considerado como um potencial candidato a controlador biológico desses helmintos.
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Akca, Atila. "Cytokine, cellular and humoral immune responses in calves experimentally-infected with Fasciola hepatica." Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366435.
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Campbell, Dan. "The identification and characterisation of novel targets in the liver fluke Fasciola hepatica." Thesis, Queen's University Belfast, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269027.
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