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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.
2
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.
3
Phiri, Isaac Khozozo. "Immunoglobulin isotype response of Fasciola spp. infected sheep and cattle to defined Fasciola spp. antigens." Thesis, University of Edinburgh, 1997. http://hdl.handle.net/1842/29943.
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Fasciolosis is a liver fluke disease, caused by Fasciola hepatica in temperate regions and high altitude areas of the tropics and subtropics and by Fasciola gigantica, which is restricted to the tropics and subtropics. Liver flukes have a wide range of definitive hosts, including man and, in particular, domestic ruminants, but the various hosts are known to differ greatly in their resistance to infection with these parasites. For example sheep are considered susceptible to challenge infection while cattle develop resistance. F. hepatica secretes the enzyme cathepsin-L1 protease (Fh-cathepsin) which has a molecular weight (MWt) of 27 kDa. It is considered to have a functional role in parasite evasion of the host immune response, through cleavage of host immunoglobulin. The enzyme, glutathione s-transferase (GST) which is of 27.8-29 kDa MWt, is also secreted by F. hepatica (Fh-GST) and is thought to be involved in the detoxification of exogenous (xenobiotic) and endogenous derived toxic compounds. Both enzymes form part of the fluke excretory/secretory (E/S) products and are of additional interest in that they are considered as vaccine candidates against fasciolosis. This study investigated the immunoglobulin isotype responses of sheep and cattle, chronically infected with F. hepatica and F. gigantica, to defined fluke antigens (F. hepatica E/S products (Fh-E/S) or F. gigantica E/S products (Fg-E/S), Fh-cathepsin and Fh-GST). It was decided to study the immune response in chronically infected animals since immunity is considered to play a potentially more important role in chronic infection than in acute infection, which is characterised by the death of the animal through anaemia and blood loss caused by the migrating flukes. Serum and faecal samples were collected weekly while the severity of the infections were defined using clinical, parasitological, haematological, biochemical and pathological parameters. Serum and faecal antibody (total Ig, IgG1, IgM, IgG2 and IgA) responses to 24-48 hour Fh-E/S, adult Fh-cathepsin and adult Fh-GST were determined by indirect Enzyme-linked Immunosorbent Assay (ELISA). The antigen recognition profile of the Fasciola spp. infected sheep and cattle to Fh-E/S and Fg-E/S was examined by sequential Western blotting.
4
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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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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6
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.
9
George, Sarah. "Chemotherapy and Drug Targets in Fasciola hepatica." Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/20335.
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Controlled multi-age infection studies demonstrated a lack of reliable detection within the first 6 weeks post-treatment using coproantigen (c)ELISA (Bio-X Diagnostics). A second cELISA is recommended for on-farm efficacy testing at 6 weeks in addition to an initial check at 1-2 weeks post-treatment. Field trials confirmed the utility of cELISA as an epidemiological monitoring tool, however results were inconclusive for the recommended field efficacy protocol and further studies are required. Fasciola hepatica burden in controlled studies correlated strongly with cELISA (R2=0.777) at necropsy, whilst addition of faecal egg count further improved this result (R2=0.835). Regression models fitted for field diagnostic data also demonstrated utilisation of the diagnostics in parallel to be the most explanatory of outcomes (R2= 0.91). These data support use of parallel diagnostics, which were found to have the greatest diagnostic sensitivity (Dsn = 0.975), although specificity was reduced (Dsp =0.7839) when compared to cELISA (Dsn = 0.842, Dsp = 0.931) or faecal egg count (Dsn = 0.842, Dsp = 0.842). Isolates of F. hepatica recovered from small ruminants with suspect TCBZ lack of efficacy were characterized in controlled experiments against TCBZ and closantel. Three of four isolates examined were susceptible to both anthelmintics. Characterization of Australian laboratory standard TCBZ-R (Oberon) and TCBZ-susceptible (s; Sunny Corner) reconfirmed TCBZ-R status and expanded knowledge of drug sensitivity. Oberon was confirmed susceptible to other drug classes, whilst Sunny Corner data were inconclusive for albendazole and clorsulon. Genetic variance of F. hepatica tubulin isotypes in Australian TCBZ-s and TCBZ-R populations was assessed using field and laboratory isolates. Selective pressure was examined via RT-PCR, cloning and sequencing. Seven novel nsSNPs were identified, including one unique to the field isolate; Numbugga.
10
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.
11
Zhang, Wei Yu. "Etude comparée de la réponse immunitaire du buffle et du mouton à l'infestation expérimentale par fasciola gigantica ou par fasciola hepatica." Rennes 1, 2004. http://www.theses.fr/2004REN10147.
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Les réponses immunitaires du Mouton (MT) et du Buffle infestés par F. Hepatica (Fh) ou F. Gigantica (Fg) ont été étudiées. Le Mouton est plus sensible à Fh qu'à Fg et le Buffle est sensible à Fg. L'augmentation des IgG spécifiques est précoce (SAI 1-2). Les MT/Fg reconnaissent des Ags de hauts PM et non les MT/Fh. La production d’éosinophiles et la lymphoprolifération induite par les PES sont plus fortes chez les MT/Fg. La production d'IFNg est précoce. La production d'IL-10 chez le MT/Fh est élevée durant toute l'infestation. Chez les MT/Fg la production d'IL-10 induite parles PESFh est plus importante que par les PESFg. Chez le Buffle/Fg, les Ags reconnus dans les PESFg sont principalement de bas PM. Les éosinophiles augmentent faiblement. La lymphoprolifération induite par les PESFg est précoce et transitoire. Les productions d’IFNg et d'IL-10 sont précoces et durent tout au long de l'infestation. Les PESFh semblent avoir un effet immunomodulateur supérieur à celui des PESFg.
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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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Martins, Liliana Sofia Hipólito Coimbra. "Contribuição para o estudo de Fasciola sp. em bovinos." Master's thesis, Universidade de Évora, 2017. http://hdl.handle.net/10174/21770.
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A contribuição para o estudo de Fasciola spp. em bovinos, deve-se à sua importância como
zoonose parasitária de origem alimentar, ao facto de ser uma doença tropical negligenciada e
aos seus elevados prejuízos económicos. Avaliou-se a frequência de Fasciola spp. nos animais
abatidos no matadouro de Beja de 13 de Março a 31 de Maio e estudaram-se os grupos de
bovinos parasitados e não parasitados. Realizou-se estudo morfométrico dos exemplares de
Fasciola spp. colhidos para identificação à espécie.
A frequência de Fasciola spp. em bovinos abatidos no matadouro de Beja no período do
estudo foi de 1,74% sendo superior nas fêmeas e em animais com mais de dois anos.
Na população estudada observaram-se exemplares com características morfométricas
compatíveis com valores de referência de Fasciola hepatica e Fasciola gigantica registados
noutros estudos. Os valores obtidos não se enquadraram de modo inequívoco nos intervalos
padronizados para as referidas espécies; Abstract:
Contribution to the study of Fasciola spp. in cattle
The contribution to the study of Fasciola spp. in cattle is due to its importance as food-borne
parasitic zoonosis, to the fact that it is a neglected tropical disease and to its high economic
losses. The frequency of Fasciola spp. was evaluated in animals slaughtered at the
slaughterhouse in Beja from 13 March to 31 May and the groups of parasitized and nonparasitized
cattle were studied. A morphometric study of the specimens of Fasciola spp. collected
for identification of the species was carried out.
The frequency of Fasciola spp. in cattle slaughtered at the Beja slaughterhouse during the
study period was 1.74%, being higher in females and in animals older than two years.
In the studied population specimens with morphometric characteristics compatible with
reference values of Fasciola hepatica and Fasciola gigantica were observed in other studies. The
values obtained did not fit unequivocally in the standard intervals for said species.
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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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Martins, Liliana. "Contribuição para o estudo de Fasciola sp. em bovinos." Master's thesis, Universidade de Évora, 2017. http://hdl.handle.net/10174/26902.
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Resumo
A contribuição para o estudo de Fasciola spp. em bovinos, deve-se à sua importância como zoonose parasitária de origem alimentar, ao facto de ser uma doença tropical negligenciada e aos seus elevados prejuízos económicos. Avaliou-se a frequência de Fasciola spp. nos animais abatidos no matadouro de Beja de 13 de Março a 31 de Maio e estudaram-se os grupos de bovinos parasitados e não parasitados. Realizou-se estudo morfométrico dos exemplares de Fasciola spp. colhidos para identificação à espécie. A frequência de Fasciola spp. em bovinos abatidos no matadouro de Beja no período do estudo foi de 1,74% sendo superior nas fêmeas e em animais com mais de dois anos. Na população estudada observaram-se exemplares com características morfométricas compatíveis com valores de referência de Fasciola hepatica e Fasciola gigantica registados noutros estudos. Os valores obtidos não se enquadraram de modo inequívoco nos intervalos padronizados para as referidas espécies
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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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Calvani, Nichola Eliza Davies. "Translocation of Fasciola hepatica via international livestock movements: development of ante-mortem molecular diagnostic tools for the identification of Fasciola spp. in livestock." Thesis, The University of Sydney, 2020. https://hdl.handle.net/2123/22464.
Full textAbstract:
Fasciolosis caused by infection with Fasciola hepatica and Fasciola gigantica is a zoonotic disease of worldwide importance, with an estimated 91 million people considered at risk of infection and livestock losses expected to exceed US $3 billion/year. Despite the significant human and animal health impacts, no test is capable of ante-mortem Fasciola spp. differentiation in areas of parasite sympatry. The aim of this thesis was to design, validate and deploy a suite of highly sensitive molecular diagnostic tools for Fasciola spp. differentiation from faecal samples to enable ante-mortem screening of livestock in Northern Laos. In combination with a traditional sedimentation method and with the use of a high-speed benchtop homogeniser, the detection and quantification of Fasciola spp. infection in 100% of cattle with low faecal egg loads (<25 EPG) was possible. The point of first detection of F. hepatica infection in experimentally-infected sheep was then examined and compared to the sedimentation and a commercially-available coproantigen ELISA. Faecal samples were first considered positive at 6, 7 and 8 weeks post infection (WPI) by coproELISA, real-time PCR and sedimentation, respectively. A simplified method using un-concentrated faecal samples was developed to increase sample throughput. The limit of detection using this method was 10 and 20 EPG for sheep and cattle, respectively. Finally, several single nucleotide polymorphism assays were developed to differentiate Fasciola spp. in faecal samples alongside a Next Generation Sequencing method to determine the contribution of nucleotides from each species. These assays were applied to 153 faecal samples collected from local cattle across 27 villages in Northern Laos to detect F. hepatica translocation in an area of SE Asia with frequent international livestock trade. Of the 91 positive samples, 11 were identified as containing F. hepatica DNA, indicating establishment of the F. hepatica lifecycle in Northern Laos.
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Páucar, Sinche Silvia Esmeralda. "Prevalencia de fasciolosis y paramphistomosis en el ganado lechero de tres distritos de la provincia de Oxapampa, Pasco." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2008. https://hdl.handle.net/20.500.12672/661.
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El objetivo del presente estudio fue estimar la prevalencia de Fasciola hepatica y de un Paramfistómido en el ganado lechero de los distritos de Huancabamba, Chontabamba y Oxapampa, de la provincia de Oxapampa, Pasco. Se colectaron 408 muestras de heces de bovinos lecheros, durante mayo y noviembre del 2006, las que fueron procesadas en el Laboratorio de Parasitología de la Facultad de Medicina Veterinaria, UNMSM, mediante el método de Sedimentación Rápida; diferenciándose los huevos de ambas especies por sus características morfológicas. En el análisis estadístico se consideró las variables lugar de procedencia y edad (2-4, 5-6 y >6 años). Los resultados mostraron prevalencias de 9.0, 5.4 y 13.4% para F. hepatica y de 18.6, 29.7 y 38.9% para un digeneo de la familia Paramphistomidae en los distritos de Huancabamba, Chontabamba y Oxapampa, respectivamente. Asimismo, se encontró el 7.5, 10 y 12.4% para F. hepatica y 21, 30.8 y 33.1% para un Paramfistómido en animales con 2-4, 5-6 y >6 años, respectivamente. El análisis de regresión logística no reportó asociación entre la presencia de Fasciola hepatica y del paramfistómido con el lugar de procedencia; así mismo no mostró asociación entre el distoma hepático y la edad de los animales; sin embargo para el paramfistómido demostró que los animales mayores de 6 años presentaron mayor probabilidad (p=0,025) de encontrarse infectados que los animales más jóvenes.The aim of the current research was to estimate the prevalence of Fasciola hepatica and a Paramfistomide in the dairy cattle from the districts of Huancabamba, Chontabamba and Oxapampa, province of Oxapampa, Pasco. 408 samples of dregs of dairy cattle were collected, during May and November, 2006, which were tested in the Laboratory of Parasitology of the Veterinary Medicine School, UNMSM, using methods such as Rapid Sedimentation test; differentiating the eggs of both species for their morphologic characteristics. In the statistical analysis some variables were considered such as the place of origin and age (2-4, 5-6 y >6 years). The results showed prevalences of 9.0, 5.4 and 13.4 % for F. hepatica and of 18.6, 29.7 and 38.9 % for a digeneo of the Paramphistomidae family in the districts of Huancabamba, Chontabamba and Oxapampa, respectively. Likewise, there were found 7.5, 10 and 12.4 % for F. hepatica and 21, 30.8 and 33.1 % for a Paramfistomide in animals with 2-4, 5-6 y >6 years, respectively. The analysis of logistic regression did not report association between the presence of Fasciola hepatica and of the paranfistomido with the place of origin; likewise it did not show association among the hepatic distoma and the age of the animals; nevertheless for the paranfistomido it demonstrated that the animals older than 6 years presented major probability (p=0,025) of being infected than the youngest animals.
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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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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/.
Full textAbstract:
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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Sadoun, Franck. "Epidémiologie, diagnostic et traitement de la distomatose à Fasciola hépatica." Bordeaux 2, 1991. http://www.theses.fr/1991BOR2M083.
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Tume, Jara Lucía, Salvador Cindy Ugarte, Ferrer Javier Díaz, and Alejandro Piscoya. "Pseudotumor inflamatorio por Fasciola hepática: a propósito de un caso." Sociedad Chilena de Infectología, 2015. http://hdl.handle.net/10757/607540.
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ntroduction: Fasciola hepatica is a parasite of the class Trematoda. It commonly has been found in developing countries. When it infects humans is characterized by a triad of fever, pain in right upper quadrant and peripheral eosinophilia. We present a 67-year-old female from a rural town of the north of Lima, Peru, it was found abdominal pain, eosinophilia and focal hepatic lesions. For this reason, a hepatic mass was the initial suspicion. The hepatic biopsy was performed and one of the findings was eosinophilia. Fasciola hepatica infection should be considered as part of differential diagnosis in hepatic tumors with eosinophilia when the origin of the patient is from endemic areas of F. hepatica.Fasciola hepática es un parásito de la clase Trematoda común en países en desarrollo. La infección en el ser humano se caracteriza por la triada de fiebre, dolor abdominal en el cuadrante superior derecho y eosinofilia. Se presenta el caso de una mujer de 67 años procedente de una zona rural al norte de Lima, con historia de dolor abdominal de seis meses de evolución, con una imagen hipodensa hepática en el TAC abdominal y eosinofilia. La biopsia hepática mostró un infiltrado inflamatorio con eosinofilia. En el diagnóstico diferencial en pacientes con un tumor hepático y eosinofilia, se deben incluir infecciones parasitarias como F. hepatica; sobre todo en pacientes que proceden de áreas endémicas.
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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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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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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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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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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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Norbury, Luke James, and s9806495@student rmit edu au. "Structure, Function and Evolutionary Studies of Fasciola Cathepsin L-like Proteases." RMIT University. Applied Science, 2008. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20081204.160915.
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Fasciola cause considerable monetary loss in the agriculture industry, while parasitism of humans is an emerging disease. Fasciola cathepsin L-like proteases are believed to aid parasite invasion and survival through a range of functions including feeding, immune evasion and modulation, tissue migration, egg production and excystment. As such these proteases are considered good targets for chemotherapies and vaccine development. Fasciola cathepsins are evolutionarily divided into clades that reflect function and life stage of expression. Analysis of F. gigantica genomic DNA and mRNA identified novel cathepsin L-like sequences which are incorporated into a phylogenetic analysis of the complete Fasciola cathepsin L-like protease family. Analysis of mRNA transcripts isolated in this study also points to trans-splicing occurring amongst cathepsin transcripts, the first time this has been identified in Fasciola species. S2 subsite specificity is important in determining substrate interactions with cathepsin L-like proteases. Previous work has shown that amino acid substitutions at this site can dramatically influence substrate specificity. A number of substitutions, specifically those that have been observed, or predicted to occur during the evolution of Fasciola cathepsins L-like proteases, were introduced into the S2 subsite of FhCatL5 at aa69 to determine their influence. The introduction of L69C and L69S substitutions resulted in low overall activity indicating their expression provides no functional advantage, thus explaining the absence of such variants amongst fluke. The L69F variant showed an increase in the ability to cleave substrates with P2 proline, indicating F69 variants expressed by fluke are also likely to have this ability, similar to that shown with L69Y and FhCatL2. The introduction of a L69W substitution leads to increased cleavage of substrates with P2 proline, along with a decrease in cleavage of substrates with P2 phenylalanine. FgCatL1G transcripts were isolated from F. gigantica metacercariae. This contrasts with FhCatL5 and FhCatL2 which have been isolated in adult F. hepatica. These cathepsins differ at aa69, possessing tryptophan, leucine and tyrosine respectively. The processing and substrate specificities of each recombinant enzyme was analysed and compared. While FhCatL5 and FhCatL2 process in vitro in a manner similar to that reported for FhCatL1, FgCatL1G requires different processing conditions, including neutral pH. Combined with FgCatL1G possessing increased stability at acidic pH, this reflects the different environment into which FgCatL1G is expressed by immature compared to the adult flukes. The substrate specificity of FgCatL1G also differed from previously reported cathepsins, with a preference for P2 proline and low activity against substrates with P2 phenylalanine. This is the first time recombinant expression and purification of a cathepsin L-like protease specific to the immature life stages of Fasciola has been undertaken and had enzyme specificity analysed. This work has expanded knowledge of the repertoire of cathepsin proteases expressed at various life-stages of the liver fluke. Vaccination and/or drug inhibition studies may in the future be targeted towards cathepsins that are expressed in either the adult or immature stage, or perhaps both in a multi-targeted approach. The knowledge gained in this study may allow such targets to be chosen.
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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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Aguilera, Quevedo Norman Edgardo. "Evaluación de fracciones antigénicas, enzimáticas de Fasciola hepatica en el diagnóstico inmunológico de fasciolosis en ovinos, equinos y porcinos." Tesis, Universidad de Chile, 2007. http://repositorio.uchile.cl/handle/2250/130785.
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Memoria para optar al Título Profesional de Médico VeterinarioLa fasciolosis es una importante infección parasitaria en Chile y otros países causada por el tremátodo, Fasciola hepatica, el cual parasita los conductos biliares de las especies de abasto y otros hospederos. Su importancia radica en las grandes pérdidas económicas que ocasiona debido a la disminución de la productividad de los animales infectados, muertes y decomiso de hígados en los mataderos, además de ser una zoonosis. El diagnóstico convencional de esta parasitosis, se realiza mediante exámenes coprológicos de sedimentación que detectan los huevos eliminados por los parásitos adultos. Esta prueba es ineficaz para el diagnóstico de las infecciones tempranas, en que los parásitos son inmaduros y aún no producen huevos (etapa prepatente de la infección). Es así como se han desarrollado pruebas inmunológicas, capaces de detectar en forma temprana esta parasitosis permitiendo la aplicación de tratamientos en forma oportuna, evitando que las fasciolas juveniles lleguen a adultas y éstas contaminen el ambiente con los huevos que salen junto con los excrementos de los animales infectados. Además, permiten el procesamiento de un alto número de muestras a la vez. El propósito de este trabajo fue evaluar la eficiencia diagnóstica de los antígenos enzimáticos purificados: Leucina aminopeptidasa (LAP) y Catepsinas L (CL1 y CL2) con sueros de animales de las especies ovina (90), porcina (60) y equina (60), comparando los resultados con la fracción antigénica de <30 kDa y con el examen post mortem de los animales estudiados. Se empleó para ello la prueba inmunodiagnóstica de ELISA, que ha demostrado ser muy eficiente según la calidad del antígeno que se emplee. El antígeno LAP fue el que presentó los resultados más satisfactorios, aunque sólo con la especie ovina, tanto en la etapa prepatente como patente de la infección con valores de sensibilidad de 86,7% y 93,3%, respectivamente. La especificidad demostrada fue de 86,7% en ambas fases de la infección. Sin embargo, los resultados obtenidos en las otras dos especies con la fracción LAP y con los antígenos enzimáticos catepsina CL1, CL2 fueron poco satisfactorios en las tres especies estudiadas, probablemente debido a una pérdida de actividad biológica a lo largo del tiempo transcurrido en el estudio. Por su parte la fracción de <30 kDa, demostró nuevamente su importancia en el diagnóstico de la fasciolosis, al obtenerse altos valores de sensibilidad de 80% y 93,3% y de especificidad de 93,3% y 96,6% en la etapa prepatente y patente de la infección en ovinos, respectivamente. La sensibilidad y especificidad de la fracción de <30 kDa en el inmunodiagnóstico de la fasciolosis en porcinos y equinos también fueron elevadas (valores entre 80% y 90%).
Proyecto FONDECYT 194-0245 Proyecto de Enlace DID E005/97
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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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McGonigle, Louise Lorna. "A novel target for chemotherapeutic intervention in the liver fluke, Fasciola hepaitca." Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492023.
Full textAbstract:
Immunocytochemistry revealed that Fasciola hepatica cathepsin L (FheCL) is widely expressed in nerves and putative myocytons in adult worms. Significantly, some FheCL immunostaining co-localised with that for FMRFamide-like peptides (FLPs) which are known to modulate neuromuscular function in flatworms. These observations drove subsequent efforts towards investigating the link between FheCL and FLPs. Next, high performance liquid chromatography and mass spectrometric methods were used to demonstrate that recombinant FheCL could efficiently cleave the flatworm neuropeptides GYIRFamide and GNFFRFamide, generating inactive peptide fragments. Further efforts examined the effects of the cathepsin L inhibitor, ZPhe- Ala-diazomethylketone (DMK) on the excitatory actions of GYIRFamide in F. hepatica muscle strips. . Although GYIRFamide was found to have excitatory actions, these were not enhanced in the presence of DMK. Subsequent efforts focussed on the development ofRNA interference (RNAi) in F. hepatica as a tool to interrogate gene function. These efforts resulted in the effective silencing of bOtll FheCL and cathepsin B (FheCB) in newly excysted juveniles (NEls) - tlle first demonstration of gene silencing in liver fluke. Furthermore, the effects of silencing on phenotype were monitored by assessing the ability of NEls to penetrate rat gut sacs. This behaviour was severely disrupted in both FheCL- and FheCB-silenced NEls, implicating both in gut penetration by the infective stage. Finally, efforts focussed on exploiting the RNAi breakthrough to investigate the proposed link between cathepsin L and FLP signalling in fluke. RNAi was used to silence FheCLI and the levels of fluke FaRP were monitored by quantitative immunocytochemistry. The silencing of FheCLl resulted in a significant elevation of FLP-immunostaining, indicating that FLPs were accumulating in fluke tissue following cathepsin L-RNAi. These observations provide compelling evidence to link cathepsin Land neuropeptide signal termination in F. hepatica - the first report of neuropeptidase activity being associated with a cathepsin protease.
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Jayaraj, Ramamoorthi, and Jayaraj@menzies edu au. "Expression of stage-specific Fasciola proteases and their evaluation in vaccination trials." RMIT University. Applied Science, 2008. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20081029.100156.
Full textAbstract:
The liver flukes Fasciola hepatica and F. gigantica cause infectious disease in ruminants and humans. The geographical range of these two parasite species (temperate and tropical respectively) ensures that infection can occur worldwide. Although anthelmintic treatment is effective against disease, emerging drug resistant strains leads to the development of a vaccine. However, despite several decades of research, there is no commercial vaccine available. The main challenge at present is to produce recombinant proteins in an immunologically active form using recombinant DNA technology. This is an essential step in Fasciola vaccine production. Cysteine proteases are probably the most important facilitators of virulence in flukes and are produced by all stages of the fluke life-cycle. Two classes of cysteine protease are found in the excretory and secretory material of liver flukes- these are cathepsin L and cathepsin B. As such, the major aims of this thesis were to investigate the expression and purification of Fasciola recombinant cysteine proteins, and characterisation by SDS-PAGE and immunoblotting using monoclonal and polyclonal antibodies. These studies demonstrate the production of functionally active cathepsin proteins in S. cerevisiae BJ3505 cells which will lead to vaccine candidate analysis. The second aim of this thesis was to determine the protective efficacy of stage specific target antigens against experimental infection. In addressing this issue, the protective efficacy of single and multivalent recombinant protein vaccinations of adult stage F. hepatica cathepsin L5, immature F. gigantica cathepsin L1g and juvenile F. hepatica cathepsin B were analysed in Sprague Dawley rats against F. hepatica infection. This study demonstrates that juvenile fluke target antigen-cathepsin B induces better immune protection than adult fluke antigen-cathepsin L5. Cocktails of juvenile and adult stage fluke recombinant proteins (cathepsin B and L5) elicited the highest protective immunity against experimental infection and this combination showed not only reduction in fluke recovery and size of flukes, but also marked diminution in the intensity of liver lesions in vaccinated rats. In order to assess the immunogenic property of an early infective stage fluke secreting cysteine protease as a vaccine candidate, DNA vaccination vectors encoding cathepsin B were analysed in BALB/c mice. In this study, the ability of four DNA vaccination strategies such as secretory, chemokine-activating, lymph node targeting vectors encoding cathepsin B were assessed by antibody titre, antibody avidity, western blotting and ELIPSOT assay. The results have further validated the immunoprophylactic potential of a cathepsin B vaccine against F. hepatica. In this study, we have expressed and attained high yields of F. gigantica cathepsin L1g from E. coli BL21, and compared this to a yeast-expressed system. This protease was over-expressed and formed insoluble inclusion bodies that were subsequently solubilised with urea or guanidine hydrochloride. In order to purify the urea-solubilised protein, step-wise urea gradient chromatography was used. For refolding of solubilised protein, a dilution and dialysis procedure was utilised. Proteolytic activity was confirmed by gelatin SDS-PAGE analysis. In conclusion, the determination of the immune potential of recombinant stage specific antigens allows the development of effective vaccines against Fasciola infection.