Dissertations / Theses: 'Protozoan parasites'

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Renteria, Flores Axel. "Novel drugs against protozoan parasites." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=116979.

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Cryptosporidium parvum and Trypanosoma brucei are two protozoan parasites that can cause life-threatening illnesses in humans. Over 70 million people on the African continent are at risk of contracting T.brucei. In the case of C.parvum, infections are cosmopolitan, and a major problem is that it can be acquired very easily and requires only an infectious dose of 10 oocysts to cause the illness. If released in the public water supplies, C.parvum can endanger entire cities. This is one reason why C.parvum is categorized as a Class B bioterrorist weapon. Despite the threat C.parvum poses and the severe illness T.brucei causes, current treatments against these parasites are insufficient. These treatments fail to consistently eliminate the parasites and cause many adverse side effects. Furthermore, no significant improvements to the efficacy of these currently available treatments have been made. Given the need to find new drugs against these parasites and improve treatments, we tested the anti-parasitic activity of two compounds against T.brucei and C.parvum, respectively. First, we looked at the in vivo activity of TH-III-149, a cyclopropyl-indol, against T. brucei and then the in vitro and in vivo activity of oleyl-PC, a phosphocholine analog, against C. parvum. To begin, we looked at the effects of TH-III-149 against T.brucei by using a CD1 mouse model of infection. We demonstrated that an 8mg/kg treatment of TH-III-149 for three days resulted in a significant decrease in parasite replication rates compared to non-treated mice. By real-time PCR quantification of blood parasitemia, we showed that non-treated, T.brucei-infected mice had a thousand-fold increase in parasite burden between day 2 and 4 of infection. In comparison, only a 7.5-fold increase in parasite burden was observed in mice treated with TH-III-149. Results from blood smears and microscopy also confirmed this reduction in the replication rate of parasites. The treatment of infected mice with TH-III-149 delayed the patent period (appearance of parasites in the blood smear) by two days when compared to non-treated mice. In non-treated mice, parasite in the blood smears appeared at day 4 of the infection, while TH-III-149-treated mice only exhibited parasites in the blood smears at day 6. In addition, this compound showed minimal signs of toxicity, as non-infected mice treated with 8mg/kg of TH-III-149 for three days did not exhibit weight loss, hepatomegaly or splenomegaly. Therefore, our results support the development of TH-III-149 as a new treatment against T.brucei. In parallel, we also tested oleyl-PC against C.parvum. We showed that in vitro oleyl-PC has an IC50 of 22.9nM against C.parvum. Toxicity was evaluated using human ileocecal adenocarcinoma cells (HCT-8 cells) and was not significant at concentrations below 100µM (TC50=153.7 µM). The ratio between the TC50 and the IC50 allowed us to calculate a therapeutic index of 6.7x103. The in vivo animal study confirmed the activity of oleyl-PC previously seen in vitro. Treating C57BL/6 IFNγR-KO mice with 40mg/kg of oleyl-PC for ten days resulted in the cure (clearance of blood parasitemia) in 75% of the mice and a percent survival of 100% after 30 days (P < 0.001). In contrast, all of the non-treated mice succumbed to C. parvum infection and died by day 11. Using real-time PCR, oleyl-PC-treated mice showed no detectable levels of parasitic DNA in their intestines 30 days post infection, which indicates that these mice successfully cleared their parasitic infections. These results were confirmed by histological analysis of sections of the ileum which were clear of C.parvum oocysts. Furthermore, after ten days of treatment with 40mg/kg of oleyl-PC, no signs of toxicity were seen in treated mice; non-infected oleyl-PC-treated mice were monitored for visible behavioral changes and weight loss. Therefore, our results support the development of oleyl-PC as a new safe and effective treatment against C.parvum.
Cryptosporidium parvum et Trypanosoma brucei sont deux parasites protozoaires qui peuvent causer des maladies mortelles chez les humains. Confinées au continent africain, les infections dues à T.brucei affectent plus de 70 millions d'habitants. Dans le cas de C.parvum, les infections qui sont cosmopolites causent un problème majeur puisque la dose infectieuse n'est que de 10 oocysts. De plus, ce parasite peut être obtenu facilement et peut mettre en danger plusieurs villes, s'il est relâché dans les eaux potables. C'est un des raisons pourquoi ce parasite a été catégorisé comme une arme bio-terroriste de classe B. Malgré les risques majeurs associés à C.parvum et la maladie sévère de T.brucei, aucun progrès n'a été fait pour améliorer les traitements actuels. Ceux-ci n'ont toujours pas réussi à démontrer leur efficacité en plus de causer des effets secondaires sérieux. Vu le besoin urgent de trouver de meilleurs traitements, nous avons testé l'activité de TH-III-149, un indole-cyclopropane, contre T.brucei dans une étude in vivo ainsi que le oleyl-PC, un analogue de la phosphocholine, contre C.parvum dans des études in vitro et in vivo. Pour commencer, nous avons observé les effets du TH-III-149 contre T.brucei dans un modèle de souris CD1. Les résultats in vivo ont démontré qu'un traitement de trois jours en utilisant 8 mg/kg cause une réduction significative dans le taux de réplication du parasite en comparaison aux souris non-traitées. En utilisant le PCR en temps réel comme méthode de quantification, nous avons démontré que la charge en parasite dans le sang des souris non-traitées a augmenté de mille fois entre les jours 2 et 4, tandis qu'elle n'a augmenté que de 7.5 fois dans les souris qui ont été traitées. Les résultats des frottis sanguins ont confirmé cette réduction dans le taux de réplication des parasites. En effet, l'apparition de parasites dans les frottis sanguins a été observée dès le jour 4 de l'infection dans les souris non-traitées, tandis qu'elle n'a pu être observée qu'à partir du jour 6 dans les souris traitées avec le TH-III-149. De plus, ce composé n'a pas révélé de signes de toxicité car les groupes de souris non-infectées traitées pendant trois jours avec 8 mg/kg n'ont pas démontré de splénomégalie, d'hépatomégalie ni de perte de poids. Donc, nos résultats supportent le développement de TH-III-149 en tant que nouveau traitement contre les infections de T.brucei. En parallèle, nous avons aussi testé l'oleyl-PC contre C.parvum. Nos résultats in vitro démontrent que la concentration nécessaire pour réduire de 50% le taux de réplication du parasite (IC50) est de 25nM. La toxicité a été évaluée en utilisant une culture entérique humaine en couche monocellulaire (HCT-8). Les résultats de celle-ci démontrent que les premiers signes de toxicité apparaissent à partir de 100µM (TC50=123µM). Le ratio entre le TC50 et le IC50 a permis de calculer un index thérapeutique de 5x103. Les résultats in vivo ont servis à confirmer l'activité in vitro de oleyl-PC. En effet, le traitement de dix jours des souris C57BL/6 IFNγR-KO avec 40mg/kg de oleyl-PC a réussi à guérir (absence de parasitémie sanguine) 75% des souris, tout en gardant un taux de survie de 100% après le jour 30 (P<0.001). En contraste, toutes les souris non-traitées ont succombées à l'infection à la fin du jour 11. En utilisant le PCR en temps réel, aucune trace d'ADN provenant de C.parvum n'a pu être détectée dans les intestins de ces souris 30 jours après l'infection. Ces résultats ont été confirmés par l'analyse des lamelles histologique de l'ilium de ces souris où l'absence d'oocyst de C.parvum a été observée. De plus, chez les souris non-infectées, un traitement de dix jours avec 40 mg/kg de oleyl-PC n'a pas causé d'effets secondaires visibles tels qu'une perte de poids. Donc, nos résultats supportent le développement de l'oleyl-PC en tant que nouveau traitement sécuritaire et efficace contre les infections de C.parvum.

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Feener, Troy Douglass. "Ingestion of waterborne protozoan parasites by Daphnia." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0020/MQ55205.pdf.

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Mohamed, H. A. "Studies on protozoan parasites of small mammals." Thesis, University of Salford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374504.

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Pollitt, Laura C. "Evolutionary ecology of transmission strategies in protozoan parasites." Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/5771.

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In recent years there has been growing interest in applying frameworks from evolutionary ecology to understand infectious disease. It is becoming increasingly apparent that the interactions between parasites within the host environment can shape parasite phenotypes underlying infection dynamics and transmission. However, the spread of the disease will crucially depend on both within-host and between-host dynamics. Bridging these scales is challenging and for vector borne parasites, such as malaria and trypanosomes, will involve gaining a much better understanding of infection dynamics both within the host and vector. I apply evolutionary ecology frameworks including social evolution, life history theory, and phenotypic plasticity to investigate how parasite phenotypes are shaped by within-host and within-vector environments and examine the implications for inhost survival and between-host transmission. Specifically, I demonstrate that; 1. Within the host; i. In accordance with theory malaria parasites detect and respond to the presence of competitors by altering reproductive strategies to maximise in-host survival. Furthermore, these strategies are fine tuned in response to variation in the within-host environment, including the availability of resources. ii. The reproductive investment strategies of malaria parasites can be applied to explain the transmission strategies of African trypanosomes. This shows how general evolutionary frameworks can be applied to a novel parasite species and demonstrates the explanatory power of an evolutionary approach. iii. The complexity of the within-host environment poses specific statistical challenges for examining the temporal dynamics of parasite life history traits that are often not adequately dealt with, potentially leading to type 1 errors. Methods to evaluate levels of autocorrelation and how to deal with it are applied to datasets of within-infection dynamics. 2. Within the vector; i. Malaria parasites undergo programmed, apoptotic cell death. The occurrence of, and putative explanation for, apoptosis in protozoan parasites is controversial. I demonstrate the importance of quantitative methods and parasite ecology in testing the evolutionary explanations for parasite apoptosis. ii. The links between within-host dynamics and within-vector dynamics are complex and can lead to counter-intuitive implications for the success of between-host transmission. Density-dependent processes result in diverse fitness costs to parasites of crowding. More broadly, these processes could explain why parasites undergo apoptosis. In general my results demonstrate, across vertebrate hosts and insect vectors, how the interactions between parasites and with their environment shapes traits important for the transmission of infectious disease.

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Rezvan, Hossein. "Studies on immunology of Leishmania mexicana." Thesis, Nottingham Trent University, 2007. http://irep.ntu.ac.uk/id/eprint/181/.

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Leishmaniasis is a worldwide disease prevalent in many tropical and sub tropical countries. Treatment of Leishmaniasis by chemotherapy is not wholly effective and is usually accompanied by unpleasant side effects. The development of an effective and inexpensive vaccine represents a practical way to control the disease, however at present no safe and effective vaccine is available. In the first part of the present study, the immunity induced by four different L. mexicana potential vaccines, including killed leishmania vaccine, Soluble L. mexicana Antigen (SLA), L. mexicana gp63 cDNA and CT26 tumour cells transfected with L. mexicana gp63, were compared. It was shown that DNA immunisation using L. mexicana gp63 generated the highest immunity to the parasite among the four tested vaccines where the killed leishmania vaccine and L. mexicana gp63 transfected CT26 tumour cells did not generate significant immunity. The efficacy of DNA immunisation by intramuscular injection or using gene gun, in generating immunity to leishmania was compared. Gene gun immunisation induced more immunity to the parasite and high levels of Th1 immune response, which were detected, one week after immunisation through determination of the IgG2a levels in blood serum. Gene gun immunisation also induced long-lasting CTL activity, which was detectable before and during the course of infection for up to 6 months. Immunogenicity of MHC class I restricted peptides derived from L. mexicana gp63 have been investigated. Using 'SYFPEITHI' software, four peptides with high affinity to human HLA-A2 and four peptides with high affinity to mouse H2-Ld were predicted, synthesized and tested in HHD II and BALB/c mice respectively. Only three of the peptides predicted with high affinity to HLA-A2 were immunogenic but only two of them were likely to be naturally processed, however, none were protective in HHD II mice against leishmania infection. Purification and application of OX40L, a ligand for T-cell co-stimulatory receptor, was investigated in L. mexicana BALB/c model. In addition to purification by protein A sepharose, the murine OX40L-IgG fusion protein produced by B9B8E2 cells (cells transfected with OX40L and IgG) was successfully purified by two novel resins, MBI & MEP. The biological activity of the OX40L-IgG purified by MBI resin was significantly higher than that of MEP or protein A sepharose resins. Application of OX40L-IgG resulted in healing of leishmania lesions or delaying in development of the lesions in leishmania-infected mice.

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Wright, Megan Holly. "Chemical tools for probing protein N-myristoylation in protozoan parasites." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/39376.

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Protein N -myristoylation is the attachment of a 14-carbon fatty acid, myristate, onto the N-terminal residue of specific proteins. This co - and post-translational modification is catalysed by myristoyl CoA:protein N -myristoyltransferase (NMT), an essential enzyme in eukaryotes. N -Myristoylated proteins have diverse roles, but typically localise to cellular membranes where many are thought to be involved in signalling or trafficking processes. NMT is a potential therapeutic target in diseases caused by parasitic protozoa, such as malaria, leishmaniasis and African sleeping sickness. N -Myristoylation is difficult to study by conventional biochemical methods. Recently chemical proteomics has emerged as a powerful technique for probing protein lipidation. In this approach chemically tagged myristic acid substrate analogues are incorporated metabolically into lipidated pro teins. Tagged proteins can then be selectively 'captured' after cell lysis via a bioorthogonal ligation reaction to install a variety of labels for further analysis. This thesis describes the development of such an approach for profiling protein lipidation in diverse systems, including human cells, Plasmodium , Leishmania and T. brucei parasites. This work includes the the synthesis of multifunctional probes for the capture of tagged proteins and characterisation of a tagged myristate analogue as a Plasmodium NMT substrate. These tools are applied in several contexts, with analysis by a combination of gel-based methods and mass spectrometry. The first de novo identification of N -myristoylated proteins in P. falciparum , T. brucei and L. donovani is described. The chemical proteomic methodology developed is also used to profile lipidation in the presence of putative NMT inhibitors to assess whether compounds act on -target in live parasites. The correlation between efficacy against the cell and on-target activity is analysed to explore NMT as a potential drug target in malaria and leishmaniasis.

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Watkins, B. "Hepatozoon infections in grey squirrels (Sciurus carolinensis) with particular reference to the effect upon the host's mononuclear phagocyte system." Thesis, University of Reading, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378311.

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Rawlinson, E. M. "Pathological changes associated with Eimeria falciformis and Eimeira vermiformis infections in the mouse (Mus musculus)." Thesis, University of Reading, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372663.

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Pugh, Hedley James. "Deposition and adhesion of cryptosporidium oocysts on surfaces." Thesis, University College London (University of London), 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300120.

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Dando, Caroline. "Studies on altered gene expression in Theileria annulata infected cells of a related lineage." Thesis, University of Glasgow, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321512.

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Moyo, Sipho Dugunye. "Comparative study of clan CA cysteine proteases: an insight into the protozoan parasites." Thesis, Rhodes University, 2015. http://hdl.handle.net/10962/d1020309.

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Protozoan infections such as Malaria, Leishmaniasis, Toxoplasmosis, Chaga’s disease and African trypanosomiasis caused by the Plasmodium, Leishmania, Toxoplasma and Trypanosoma genuses respectively; inflict a huge economic, health and social impact in endemic regions particularly tropical and sub-tropical regions. The combined infections are estimated at over a billion annually and approximately 1.1 million deaths annually. The global burden of the protozoan infections is worsened by the increased drug resistance, toxicity and the relatively high cost of treatment and prophylaxis. Therefore there has been a high demand for new drugs and drug targets that play a role in parasite virulence. Cysteine proteases have been validated as viable drug targets due to their role in the infectivity stage of the parasites within the human host. There is a variety of cysteine proteases hence they are subdivided into families and in this study we focus on the clan CA, papain family C1 proteases. The current inhibitors for the protozoan cysteine proteases lack selectivity and specificity which contributes to drug toxicity. Therefore there is a need to identify the differences and similarities between the host, vector and protozoan proteases. This study uses a variety of bioinformatics tools to assess these differences and similarities. The Plasmodium cysteine protease FP-2 is the most characterized protease hence it was used as a reference to all the other proteases and its homologs were retrieved, aligned and the evolutionary relationships established. The homologs were also analysed for common motifs and the physicochemical properties determined which were validated using the Kruskal-Wallis test. These analyses revealed that the host and vector cathepsins share similar properties while the parasite cathepsins differ. At sub-site level sub-site 2 showed greater variations suggesting diverse ligand specificity within the proteases, a revelation that is vital in the design of antiprotozoan inhibitors.

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Dyall, Sabrina Devi. "Characterisation of the LmcDNA2 gene family of Leishmania major." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243853.

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Cotterell, Sarah Elizabeth Jane. "The production and recruitment of leukocytes during murine visceral leishmaniasis." Thesis, London School of Hygiene and Tropical Medicine (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321966.

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Miné, Júlio César [UNESP]. "Diagnóstico laboratorial de blastocistose humana - ocorrência de Blastocystis hominis (BRUMPT,1912) em habitantes da região de Araraquara-SP." Universidade Estadual Paulista (UNESP), 2005. http://hdl.handle.net/11449/95827.

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Made available in DSpace on 2014-06-11T19:27:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-06-24Bitstream added on 2014-06-13T18:56:48Z : No. of bitstreams: 1 mine_jc_me_arafcf.pdf: 726384 bytes, checksum: 6f4cf343dd34895158b4fd037741c3af (MD5)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Universidade Estadual Paulista (UNESP)
Blastocystis hominis é protozoário causador da infecção intestinal denominada blastocistose humana, cujo diagnóstico é realizado pelo exame coproparasitológico e por meio de técnicas de colorações permanentes que foram utilizadas neste estudo para avaliar a prevalência de Blastocystis hominis nos espécimes fecais de habitantes na região de Araraquara-SP. Foram estudadas 503 amostras de fezes submetidas às técnicas de exame direto a fresco, de Faust e cols., de Lutz e de Rugai, Mattos e Brisola, além das colorações pela hematoxilina férrica, tricrômio e de Kinyoun modificada. Do total das amostras analisadas 174 (34,6%) apresentaram-se positivas para a presença de parasitas intestinais. O protozoário e helminto mais freqüentes foram respectivamente: Entamoeba coli (14,6%) e Strongyloides stercoralis (6,7%). Blastocystis hominis foi observado em 23 (4,6%) amostras fecais com consistência predominantemente pastosa, não caracterizando quadro diarréico. Apesar da baixa prevalência de Blastocystis hominis encontrada na região de Araraquara, comparativamente a outras regiões brasileiras, é importante a realização do diagnóstico laboratorial desse protozoário. O encontro de Blastocystis hominis em material fecal é indicativo de contaminação de alimentos e água de consumo, desde que se admita a rota de transmissão oral-fecal deste parasita, o que implica na orientação da população sobre as medidas de saneamento básico e higiene como meio para se controlar problemas de saúde ocasionados pelos enteroparasitas.
Blastocystis hominis is a protozoan which causes an intestinal infection called human blasticistosis. Its diganosis is perfomed by stool examination and permanent staining techniques. Such methodologies were carried out on the present study in order to evaluate the prevalence of Blastocystis hominis in faecal specimens from the Araraquara region inhabitants. A total of 503 faecal samples were evaluated by the following techniques: examination fo fresh specimens, Lutz, Faust et al. and Rugai et al. besides the iron hemotoxylin, trichrome and modified Kinyon staining. Out of 503 stool samples examined 174 (34,6) were found to be positive for intestinal parasites. The most prevalent protozoan and helminth parasites were Entamoeba coli (14,6%) and Strongyloides stercoralis (6,7%) respectively. Balstocystis hominis was present in 23 (4,6%) stool samples, most of all of soft consistence and without diarrheic reports. Blastocystis hominis laboratorial diagnosis is important althought its prevalence has been low in Araraquara region. Blastocystis hominis findings is faecal specimens indicates the food and water contamination and since the transmission of this parasite is iral-faecal it implies that the population needs orientation about hygiene and basic sanitation conditions in order to control health problems caused by enteroparasites.

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Roques, Magali. "Caracterisation moléculaire et fonctionnelle de la jonction mobile contrôlant l'invasion de la cellule hôte par Toxoplasma gondii." Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20250/document.

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Caractérisation moléculaire et fonctionnelle de la jonction mobile contrôlant l'invasion de la cellule hôte par Toxoplasma gondii. Les apicomplexes sont des parasites eucaryotes responsables d'infections humaines et animales, dont le paludisme et la toxoplasmose. La plupart sont des parasites intracellulaires obligatoires ; l'entrée dans la cellule hôte est donc un évènement crucial dans leur cycle de développement. Ce processus, conservé au sein du phylum, implique la sécrétion séquentielle du contenu de deux organites : les micronèmes et les rhoptries. Lors de l'invasion, le parasite établit un contact étroit entre son extrêmité apicale et la membrane plasmique de la cellule hôte, appelé la jonction mobile (JM). La JM est un point d'ancrage à la cellule hôte qui est initié chez Toxoplasma par la sécrétion de protéines du col des rhoptries appelées TgRON2/RON4/RON5/RON8 (complexe de RONs). Ces protéines sont sécrétées dans la cellule hôte et TgRON2 est insérée dans la membrane de la cellule hôte. TgRON2 peut servir de récepteur à la protéine TgAMA1 (Apical Membrane Antigen 1) qui est une protéine de micronèmes sécrétée à la surface du parasite durant l'invasion. L'interaction AMA1-RON2 est également conservée chez Plasmodium, mais il n'existe pas de réactivité croisée entre espèces d'apicomplexes. La résolution de la structure de la protéine recombinante TgAMA1 en complexe avec un peptide TgRON2 nous a permis de déterminer des résidus critiques à l'interaction entre ces deux protéines in vitro et à l'invasion du parasite in vivo, et de définir les bases structurales de la spécificité intra-espèce de l'interaction AMA1-RON2. Par l'obtention d'une souche dépourvue de TgAMA1, nous montrons qu'AMA1 n'est pas essentielle à la survie du toxoplasme, comme il avait été supposé depuis longtemps. Nous confirmons le rôle clé de cette protéine dans l'invasion et la formation de la JM. Les mutants dépourvus d'AMA1 sont capables d'insérer le complexe de RONs dans la cellule hôte mais se détachent plus fréquemment, entrainant des invasions abortives. L'invasion résiduelle observée en absence d'AMA1 pourrait impliquer des protéines homologues à TgAMA1, TgRON2 et TgRON4, dont nous avons entamé la caractérisation moléculaire et fonctionnelle.Mot-clés : Apicomplexes, Toxoplasma gondii, invasion, jonction mobile, micronèmes, rhoptries
Molecular and functional characterisation of the moving junction controlling host cell invasion by Toxoplasma gondiiAbstract:Apicomplexa are eukaryotic parasites responsible for a variety of human and animal diseases, including malaria or toxoplasmosis. Most of them have an obligatory intracellular stage; thus, the invasive process is a crucial step in their developmental cycle. It implies the sequential secretion of two organelles: micronemes and rhoptries. During invasion, the parasite establishes a structure called the moving junction (MJ), which is a close apposition between the apical end and the plasma membrane of host cell. The MJ is an anchoring point for invasion that is initiated in Toxoplasma by the secretion of rhoptry neck proteins named TgRON2/RON4/RON5/RON8 (the RONs complex). These proteins are exported to the host cell cytoplasm and TgRON2 spans the host cell membrane. There, TgRON2 will function as a receptor to Apical Membrane antigen 1 (TgAMA1), which is a micronemal protein displayed on the surface of the parasite during the invasion process. The AMA1-RON2 interaction is conserved in Plasmodium but there is no interspecies cross-binding.We have determined the structure of a TgAMA1 recombinant protein in complex with a TgRON2 peptide, which allowed us to determine which residues are critical for the interaction between both proteins in vitro and for parasite invasion in vivo. Moreover, the co-structure explains at the structural level the evolutionary constraint of the AMA1-RON2 interaction. By generating an AMA1 null strain in T. gondii, we demonstrate that TgAMA1 is not an essential gene, as claimed before. We confirm the importance of AMA1 in invasion and its key role in MJ formation. AMA1 null parasites insert the RON complex into the host cell but are more frequently detached from it, causing abortive invasions. The residual invasion might involve proteins homologous to TgAMA1, TgRON2 and TgRON4, for which the molecular and functional characterization is undertaken.Keywords: Apicomplexes, Toxoplasma gondii, invasion, moving junction, micronemes, rhoptries

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Sweeny, Joshua. "Determining the impact of protozoan and strongylid parasites on meat lamb productivity: Utilising molecular diagnostic methods for the detection of internal parasites in lambs." Thesis, Sweeny, Joshua (2012) Determining the impact of protozoan and strongylid parasites on meat lamb productivity: Utilising molecular diagnostic methods for the detection of internal parasites in lambs. PhD thesis, Murdoch University, 2012. https://researchrepository.murdoch.edu.au/id/eprint/10633/.

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Internal parasites (strongylid gastrointestinal helminths) have been reported to decrease lamb productivity in extensive grazing sheep enterprises. Increased interest into intestinal, protozoan parasites; Cryptosporidium and Giardia, has arisen due to their potential public health risks. Little research has examined their prevalence and impact on productivity in extensively managed livestock. Despite molecular diagnostic techniques having the capability to facilitate rapid identification, improve control and enhance prevention strategies for disease pathogens, little investigation has been conducted to compare molecular tests with traditional diagnostic methods. Longitudinal studies observed that 47–81% of lambs sampled, tested positive for Cryptosporidium or Giardia at least once in their lives over five sampling occasions. Cryptosporidium xiaoi and G. duodenalis assemblage E were the most common species/genotypes isolated from Pingelly (Farm A) and Arthur River (Farm B). Zoonotic species/genotypes were also isolated but in low numbers. Cryptosporidium xiaoi was isolated on two occasions from dam water on Arthur River, while C. ubiquitum and G. duodenalis assemblage E were detected in dam water from Frankland. A novel, possibly new genotype (sheep genotype I) was identified in six Cryptosporidium isolates from Arthur River. Cryptosporidium parvum and C. ubiquitum were the most common species detected in Boyup Brook and Kojonup flocks. Statistical analyses revealed lambs positive for Cryptosporidium on at least one sampling occasion had lighter HCWs and lower dressing percentages when compared to lambs never positive for Cryptosporidium for Farms A and B, respectively. On Farm B, lambs positive for Giardia on at least one occasion had lighter HCWs and lower dressing percentages when compared to lambs never positive for Giardia. Cryptosporidium-positive lambs at the second sampling were 3.84–4.72 times more likely to have non-pelleted faeces (faecal consistency score [FCS] ≥ 3), when compared to Cryptosporidium-negative lambs for Farms A and B. Lambs on Boyup Brook and Kojonup farms that were positive for Cryptosporidium, Giardia or both, were 2.4–14.0 times more likely to have non-pelleted faeces. Furthermore, a higher number of internal parasites detected per lamb was associated with lower body condition score (BCS) and higher FCS on the Boyup Brook and Kojonup farms. Cryptosporidium-positive lambs were 3.36–2.96 times more likely to have moderate to severe breech fleece faecal soiling scores (3 – 5), when compared to Cryptosporidium-negative lambs at the second sampling for Farms A and B. Live weight, growth rate and BCS were inconsistently associated with protozoa detection across different samplings and farms. A further study compared the performances of two lamb flocks exposed to different natural strongylid larval challenges. A new innovative, molecular approach was developed to recover strongylid larvae from pasture, which had a strong, negative correlation (r2=0.91–0.95) with pasture larval counts used to detect and quantify strongylid larvae species on pasture. Flock L (exposed to a low larval challenge) had greater dressing percentages greater than Flock S (exposed to a higher larvae challenge). Within flock analyses of the Frankland flocks found lambs positive for Giardia at least once had lighter HCWs and lower dressing percentages, when compared to lambs never positive for Giardia. A written questionnaire which surveyed 139 (41.4%) meat lamb enterprise owners/managers in southern Western Australia, found evidence of diarrhoea was reported on 64.8% of farms. A binary logistic regression analysis revealed that the source of livestock drinking water was associated with the incidence of diarrhoea. Lamb flocks that sourced water from a dam, were 117 times more likely to have active or recent evidence of diarrhoea. Overall, 10.1% and 14.4% of respondents were aware of Cryptosporidium and Giardia, respectively. Comparison between a molecular diagnostic technique (identifying strongylid species by screening genomic DNA extracted directly from faeces) and the traditional McMaster WEC method, found high levels of agreement (kappa statistic ≥0.93) between the test results for detecting patent strongylid infections in two separate epidemiological studies. The findings that some lambs tested negative for strongylid infections while grazing pastures known to be infested with larvae, together with the strong correlations between WEC and the number of strongylid species detected per lamb, both suggest that strongylid eggs are the likely main source of strongylid DNA. The findings of this thesis suggest that molecular identification of internal parasites is potentially negatively associated with phenotypic performance traits of lambs. Protozoa-positive lambs had reduced production performances (lighter carcase weights and reduced dressing percentage), when compared to protozoa-negative lambs. For such molecular techniques as that were employed in this research to be introduced into routine veterinary diagnostics, they need to: (1) quantify the magnitude of infections, (2) provide cost-benefits to sheep producers, (3) display consistent associations/correlations with phenotypic performance traits of livestock and (4) be cost-beneficial for diagnostic laboratories to conduct (sales volume and equipment costs). The future development of multiplex, real-time, quantitative PCR (qPCR) assays capable of detecting and quantifying multiple pathogen infections (parasites and bacteria) in a single assay, would facilitate the uptake of such tests for both veterinary and human diagnostics

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au, pmenon1@optusnet com, and Kathleen Ilona Menon. "Assessment of the Antiprotozoal Activity of some Tubulin Inhibitors Following Cyclodextrin Complexation." Murdoch University, 2002. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20040820.133836.

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The purpose of the present study was to evaluate the potential usefulness of tubulin inhibitors when complexed with hydroxypropyl-â-cyclodextrin (ÇPâCD) against a range of protozoan parasites. This approach involved investigations into the complexation of these drugs with ÇPâCD, and subsequent investigations of these drugs and their complexes in regard to cytotoxicity, pharmacokinetics, in vitro efficacy against Giardia, Cryptosporidium and rodent malaria (Plasmodium chabaudi), and their in vivo efficacy against Giardia and malaria. Albendazole (ABZ) is a benzimidazole carbamate with a broad anti-parasite spectrum, while the dinitroanilines trifluralin (TF) and oryzalin (OZ) have recently been found to exhibit activity against certain parasites. All three compounds are microtubule antagonists in either nematodes or weeds and have poor aqueous solubility, with the solubility of ABZ and OZ dependent on pH. Cyclodextrins (CD) have a hydrophobic cavity that allows them to form inclusion complexes with hydrophobic drugs, resulting in increased drug aqueous solubility, and often, improved drug dissolution and bioavailability. Thus the complexation of these drugs with ÇPâCD was investigated. All three compounds exhibited type AL phase solubility diagrams with ÇPâCD complexation, with additional increases in ABZ and OZ solubility achieved through the manipulation of temperature and pH. OZ displayed a stronger interaction with ÇPâCD when ionised over its neutral form. However, insufficient concentrations of the TF/ÇPâCD complex were achieved for drug efficacy studies. The cytotoxicity of the drugs and their complexes was assessed using the assay kit Cytotox 96 with human carcinoma cells. This is a colourimetric assay that measures lactate dehydrogenase release as a consequence of compromised cellular and membrane integrity. Both ABZ and OZ are cytotoxic to rapidly proliferating and differentiating cells but are not cytotoxic to cells in the stationary phase. Complexation did not affect drug cytotoxicity. In pharmacokinetic studies, complexation improved ABZ (and metabolites) bioavailability, but had no significant affect on OZ bioavailability. In vitro drug assessment studies found ABZ to be highly effective against Giardia, and effectiveagainst Cryptosporidium and malaria. OZ on the other hand exhibited no activity against Giardia, but was effective against Cryptosporidium and malaria. Complexation did not improve the antiprotozoal efficacy of either ABZ or OZ. In particular, excess ÇPâCD decreased the antigiardial effects of ABZ, possibly due to competitive complex formation. In addition, complexation did not improve the antiprotozoal effects of ABZ in vivo. However, the cytotoxic effect of the ABZ/ÇPâCD complex was more evident in the treatment of malaria in vivo, resulting in increased anaemia and suppression in weight gain, due to the improved bioavailability of ABZ and metabolites. ÇPâCD alone was found to be cytotoxic at greater than 2.5%, and inhibited Giardia both in vitro and in vivo at greater than 1% and 2% respectively. This was attributed to membrane disruption caused by the dissolution and removal of membrane components. In comparison, malaria grew better in the presence of ÇPâCD in vitro, with no detrimental effect observed at up to 8% ÇPâCD. This was attributed to either the increased solubilization of a necessary media component, or the complexation and removal of an inhibitory compound from the cultivation medium. Therefore ÇPâCD complexation did not improve the antiprotozoal activity of the tubulin antagonists ABZ and OZ. However, the results of the pharmacokinetic studies suggest that anthelmintic activity of ABZ, particularly against systemic infections, may be improved with oral administration of the ABZ/ÇPâCD complex. In addition, the antiparasitic activity of ÇPâCD alone may be promising, especially against intestinal infections. Finally, the improved in vitro cultivation of P. chabaudi in the presence of ÇPâCD presents a promising approach to its potential long term cultivation.

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Anthony, Jean-Paul. "The inhibitory properties, and mode of action, of plant essential oils and fruit extracts on protozoan parasites." Thesis, Queen Margaret University, 2008. https://eresearch.qmu.ac.uk/handle/20.500.12289/7382.

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The main aims and objectives of this study was to determine if plant essential oils (PEOs) and polyphenol-rich fruit extracts (PRFEs) could reduce the viability of Giardia duodenalis trophozoites, Trypanosoma cruzi epimastigotes and Cryptospordium parvum oocysts in vitro. All PEOs tested reduced epimastigote and trophozoite viability at a concentration of 0.02% v/v, with titrations of the PEOs showing a concentration dependant decrease in viability. The minimum inhibitory concentrations (MICs) of PEOs demonstrated that myrtle and elemi oil were the most active PEOs (trophozoites = 0.005% v/v; epimastigotes = 0.00125% v/v) with the terpenes, α-pinene and limonene, constituents of these oils, being responsible for their action. Incubation of palmarosa oil and its terpene, geraniol, with C. parvum oocysts caused the almost complete excystation of oocysts (in the presence of increased temperature and time), with geranium oil and its terpene, citronellol, being nearly as effective. PRFEs reduce trophozoite viability, with 4 members of the Rosaceae Family causing complete reduction at 167 μg ml-1, possibly through their ellagitannin content. Cloudberry extract was found to have an MIC comparable to the drug metronidazole (67 μg ml-1). The historical use of blueberries for the treatment of diarrhoeal diseases was demonstrated by the ability of blueberry PRFE, pressed juice and drink to kill trophozoites. Protein expression was both inhibited and upregulated in several proteins in whole cell lysates of PEO treated trophozoites, indicating a supplemental intracellular mode of action. Both PEOs and PRFEs cause morphological changes to epimastigotes and trophozoites through flagellar truncation and internalisation, swelling and rounding of the cell body, cytoplasmic condensation and the formation of large membrane protrusions. These indicate an action on the membrane itself with possible changes in osmoregulation. Both PEOs and PRFEs can be considered to be candidates for novel drug discovery for the treatments of cryptosporidiosis, giardiasis and American trypanosomiasis.

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CARADONNA, TIZIANA. "Emerging protozoan parasites and food safety: investigation in 'ready to eat' packaged salads by microscopy and molecular tools." Doctoral thesis, Università di Foggia, 2017. http://hdl.handle.net/11369/363293.

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Per esaminare la prevalenza della contaminazione da Giardia duodenalis, Cryptosporidium spp., Toxoplasma gondii e Cyclospora cayetanensis in insalate pronte da mangiare (RTE) in vendita in Italia, sono stati acquistati 648 pacchetti prodotti da aziende industriali e locali. Ogni mesi, nove pacchetti (100 g ciascuno) sono stati raccolti per ogni marchio e 72 pools sono stati creati e sottoposti a microscopia e analisi molecolari. 864 slide sono state esaminate microscopicamente e Cryptosporidium spp. e anche Blastocystis hominis e Dientamoeba fragilis sono stati rilevati. Attraverso gli strumenti molecolari sono stati identificati G. duodenalis assemblaggio A, Cryptosporidium parvum e Cryptosporidium ubiquitum, T. gondii Tipo I e C. cayetanensis. B. hominis e D. fragilis sono stati anche confermati in modo molecolare. La prevalenza complessiva di ciascuna specie di protozoo è stata del 0,6% (95% CI 0,2-1,6%) per G. duodenalis, 0,8 (95% CI 0,3-1,8%) per T. gondii, 0,9% (95% CI 0,4-2,1) per Cryptosporidium spp. e 1,3% (95% CI 0,6-2,5%) per C. cayetanensis mentre la prevalenza per B. hominis è stata del 0,5% (95% CI 0,1-1,4%) e 0,2% (95% CI 0,0-0,9%) per D. fragilis. In totale, utilizzando sia microscopia che strumenti molecolari, il 4,2% (95% CI 2,6-6,2%) dei campioni era contaminato da almeno 1 specie di protozoo e 0,6% (95% CI 0,2-1,6%) di questi era contaminato da almeno due specie. Il numero di oocisti per T. gondii e C. cayetanensis nei campioni test-positivi qPCR è stato stimato da 62 a 554 e da 46 a 1.580 per g di prodotto vegetale rispettivamente. Il presente lavoro di dottorato rappresenta il primo studio su larga scala sulla presenza di protozoi in insalate confezionate in Europa. I risultati mostrano che la prevalenza delle specie di protozoi nelle insalate RTE è una causa di preoccupazione per la salute umana in Europa e in particolare in Italia. In attesa dell'inclusione di questi protozoi nella legislazione europea e nazionale per ridurre i rischi di contaminazione nelle insalate RTE e ridurre al minimo la loro trasmissione alimentare, i nostri risultati indicano la necessità di ulteriori studi di sorveglianza sulle possibili fonti di contaminazione alimentare. I metodi di campionamento progettati in questa ricerca e i risultati ottenuti possono fornire la direzione per altri studi sorveglianza e il monitoraggio di prodotti freschi in altre aree. Inoltre, essi possono fornire la base per le linee guida sulla sicurezza alimentare, basate anche sul sistema HACCP, al fine di ridurre il rischio di contaminazione nelle insalate RTE e ridurre al minimo la trasmissione di malattie alimentari.
To investigate the prevalence of protozoan contamination by Giardia duodenalis, Cryptosporidium spp., Toxoplasma gondii and Cyclospora cayetanensis, in ‘ready to eat’ (RTE) salads on sale in Italy, 648 packages from industrial and local brands were purchased. Nine individual packages from each brand were collected per month, pooled and subjected to microscopy and molecular analyses. 864 slides were microscopically examined and Cryptosporidium spp. and also Blastocystis hominis and Dientamoeba fragilis were detected. By molecular tools G. duodenalis assemblage A, Cryptosporidium parvum and Cryptosporidium ubiquitum, T. gondii Type I and C. cayetanensis were identified. B. hominis and D. fragilis were also molecularly confirmed. The overall prevalence of each protozoan species was 0.6% for G. duodenalis, 0.8% for T. gondii, 0.9% for Cryptosporidium spp., and 1.3% for C. cayetanensis, whereas the prevalence of B. hominis and D. fragilis were 0.5% and 0.2%, respectively. By microscopy and/or molecular tools, 4.2% of the samples were contaminated by at least one protozoan species, and 0.6% of them showed contamination of two protozoan species with a range number of oocysts from 62 to 554 per g of vegetable for T. gondii, and 46 to 1.580 for C. cayetanensis. This is the Europe’s first large-scale study on the presence of protozoans in packaged salads. The results show that the prevalence of protozoan species in RTE salads is a cause for concern about human health in Europe, and in particular in Italy. Pending the inclusion of protozoan parasites in EU and Italian legislation to reduce the risks of RTE contamination and minimize their foodborne transmission, our results indicate the need for additional surveillance studies of possible sources of food contamination. The sampling methods designed in this research and the results obtained can provide the direction for monitoring fresh produce in other areas, and for surveillance studies on products. In addition, they can provide the basis for food safety guidelines, based also on the HACCP system, in order to reduce the risk of RTE contamination and to minimize foodborne disease transmission

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Miné, Júlio César. "Diagnóstico laboratorial de blastocistose humana - ocorrência de Blastocystis hominis (BRUMPT,1912) em habitantes da região de Araraquara-SP /." Araraquara : [s.n.], 2005. http://hdl.handle.net/11449/95827.

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Orientador: João Aristeu da Rosa
Banca: Vera Lucy de Santi Alvarenga
Banca: Vera Lucia Pagliusi Castilho
Resumo: Blastocystis hominis é protozoário causador da infecção intestinal denominada blastocistose humana, cujo diagnóstico é realizado pelo exame coproparasitológico e por meio de técnicas de colorações permanentes que foram utilizadas neste estudo para avaliar a prevalência de Blastocystis hominis nos espécimes fecais de habitantes na região de Araraquara-SP. Foram estudadas 503 amostras de fezes submetidas às técnicas de exame direto a fresco, de Faust e cols., de Lutz e de Rugai, Mattos e Brisola, além das colorações pela hematoxilina férrica, tricrômio e de Kinyoun modificada. Do total das amostras analisadas 174 (34,6%) apresentaram-se positivas para a presença de parasitas intestinais. O protozoário e helminto mais freqüentes foram respectivamente: Entamoeba coli (14,6%) e Strongyloides stercoralis (6,7%). Blastocystis hominis foi observado em 23 (4,6%) amostras fecais com consistência predominantemente pastosa, não caracterizando quadro diarréico. Apesar da baixa prevalência de Blastocystis hominis encontrada na região de Araraquara, comparativamente a outras regiões brasileiras, é importante a realização do diagnóstico laboratorial desse protozoário. O encontro de Blastocystis hominis em material fecal é indicativo de contaminação de alimentos e água de consumo, desde que se admita a rota de transmissão oral-fecal deste parasita, o que implica na orientação da população sobre as medidas de saneamento básico e higiene como meio para se controlar problemas de saúde ocasionados pelos enteroparasitas.
Abstract: Blastocystis hominis is a protozoan which causes an intestinal infection called human blasticistosis. Its diganosis is perfomed by stool examination and permanent staining techniques. Such methodologies were carried out on the present study in order to evaluate the prevalence of Blastocystis hominis in faecal specimens from the Araraquara region inhabitants. A total of 503 faecal samples were evaluated by the following techniques: examination fo fresh specimens, Lutz, Faust et al. and Rugai et al. besides the iron hemotoxylin, trichrome and modified Kinyon staining. Out of 503 stool samples examined 174 (34,6) were found to be positive for intestinal parasites. The most prevalent protozoan and helminth parasites were Entamoeba coli (14,6%) and Strongyloides stercoralis (6,7%) respectively. Balstocystis hominis was present in 23 (4,6%) stool samples, most of all of soft consistence and without diarrheic reports. Blastocystis hominis laboratorial diagnosis is important althought its prevalence has been low in Araraquara region. Blastocystis hominis findings is faecal specimens indicates the food and water contamination and since the transmission of this parasite is iral-faecal it implies that the population needs orientation about hygiene and basic sanitation conditions in order to control health problems caused by enteroparasites.
Mestre

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Duarte, Barbosa Amanda. "Prevalence, genetic diversity and potential clinical impact of blood-borne and enteric protozoan parasites in some Australian native mammals." Thesis, Duarte Barbosa, Amanda ORCID: 0000-0003-3289-1445 (2017) Prevalence, genetic diversity and potential clinical impact of blood-borne and enteric protozoan parasites in some Australian native mammals. PhD thesis, Murdoch University, 2017. https://researchrepository.murdoch.edu.au/id/eprint/40258/.

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Blood-borne and enteric protozoan parasites belonging to the genera Trypanosoma, Babesia, Theileria, Cryptosporidium and Giardia are responsible for severe animal and human illnesses worldwide. In addition, parasites of the genus Hepatozoon have been associated with animal morbidity and mortality. Despite recent research and improved knowledge of the taxonomy and distribution of native Australian protozoan parasites, still relatively little is known about their epidemiology, genetic diversity and pathogenicity. The overarching aim of this thesis was to determine the prevalence, molecular characterisation and potential clinical impact of protozoan pathogens of potential conservation and zoonotic importance in Australian native mammals. A total of 465 blood samples, 167 faecal samples and 91 ticks were collected from mammals belonging to seven target species: common brush-tailed possums (Trichosurus vulpecula), northern brown bandicoots (Isoodon macrourus), northern quolls (Dasyurus hallucatus), brush-tailed rabbit-rats (Conilurus penicillatus), koalas, a little red flying fox (Pteropus scapulatus) and grey-headed flying foxes (Pteropus poliocephalus). The sampling was undertaken across four states/territories in Australia: the Northern Territory (NT), Queensland (Qld), New South Wales (NSW) and South Australia (SA). Molecular and morphological analyses were utilised to identify and characterise Trypanosoma, Babesia, Theileria, Hepatozoon, Cryptosporidium and Giardia. The potential clinical impact of the parasites identified was investigated by associating clinical, haematological and biochemical parameters, whenever available, with presence or absence of infection. A molecular survey was conducted in the NT to investigate the prevalence, genetic diversity and potential pathogenicity of protozoan parasites in common brush-tailed possums, northern brown bandicoots, northern quolls, and brush-tailed rabbit-rats. Overall, 22.5% (95% confidence interval (CI): 17.0-28.8%) of the animals tested were positive for haemoprotozoans by Polymerase Chain Reaction (PCR) targeting the 18S ribosomal RNA (rRNA) gene. Trypanosoma vegrandis and T. noyesi were found in 26.6% (95% CI: 18.7-35.7%) of the bandicoots and in 23.7% (95% CI: 11.4-40.2%) of the possums, respectively. Babesia spp. and Hepatozoon spp. were identified in bandicoots only, both at a prevalence of 5.3% (95% CI: 2.7-9.3%). Hepatozoon gamonts were detected using light microscopy in two out of 11 animals positive for this parasite by PCR. Faecal samples were tested for Cryptosporidium spp. at the 18S rRNA locus, and for Giardia spp. at the glutamate dehydrogenase (gdh) and 18S rRNA loci. The total prevalence of intestinal protozoan parasites observed was relatively low (3%; 95% CI: 1.0-6.9%). No clear signs of major morbidity were observed in infected animals, however bandicoots positive for Trypanosoma exhibited a significantly lower packed cell volume (PCV) compared to negative bandicoots (p = 0.046). The first report of T. vegrandis in koalas using morphology and sequence analysis of the 18S rRNA gene is also described. The prevalence of T. vegrandis in koalas was (13.6%; 95% CI: 5.2-27.4%). In addition, a novel next-generation sequencing (NGS)-based assay for Trypanosoma, developed during the present study, revealed that mixed infections with up to five trypanosome species in koalas were significantly more prevalent (27.4%; 95% CI: 21-35%) than single trypanosome infections (4.8%; 95% CI: 2-9%). Infections with T. gilletti, T. irwini, T. copemani and T. vegrandis were identified. Additionally, T. noyesi was detected for the first time in koalas, although at a low prevalence (0.6%; 95% CI: 0-3.3%), and a novel species (Trypanosoma sp. AB- 2017) was identified at a prevalence of 4.8% (95% CI: 2.1-9.2%). Overall, a considerably higher proportion (79.7%) of the Trypanosoma sequences isolated from koala blood were identified as T. irwini, suggesting this was the dominant species. The study also employed the NGS methodology to profile trypanosome communities within Ixodes holocyclus and I. tasmani ticks removed from koala hosts. Co-infections involving T. gilletti, T. irwini, T. copemani, T. vegrandis and Trypanosoma sp. AB- 2017 were also detected in the ticks, with T. gilletti and T. copemani being the dominant species within the invertebrate hosts. This thesis also characterised a novel trypanosome species in a little red flying fox with clinical signs of trypanosomiasis, using morphology and molecular analyses at the 18S rRNA and Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) loci. Morphological comparison showed that trypomastigotes of the novel species were significantly different from those of Trypanosoma pteropi and T. hipposideri, two species previously described from Australian bats for which genetic information was unfortunately not available. Phylogenetic analysis revealed that the novel species was genetically distinct and clustered with other bat-derived trypanosome species within the Trypanosoma cruzi clade. The discovery of a new bat-derived trypanosome species in Australia prompted the screening of an additional 87 blood samples from grey-headed flying foxes, which were negative for Trypanosoma 18S rDNA. In summary, this research provides new insights on the prevalence, spatial distribution, inter- and intra-specific genetic diversity and the potential negative effects of bloodborne and enteric protozoan parasites on the health of Australian mammals. Furthermore, the identification of trypanosome polyparasitism in koalas and two species of native ticks will inform future epidemiological conservation studies. The outcomes of this thesis may be used to inform wildlife management and zoonotic disease programs.

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Terzic, Vida. "Utilisation de la chimie "click" pour visualiser la pénétration de principes actifs dans les protozoaires parasites." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS190/document.

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La recherche de nouvelles molécules à activité antiparasitaire pour lutter contre les parasites responsables de maladies telles que le paludisme ou la trypanosomiase humaine africaine est un enjeu primordial car il n’existe pas de vaccin pour ces maladies qui peuvent être mortelles et qui touchent près de 1/6 de la population mondiale. Dans ce contexte, il a été observé au laboratoire que l’amélioration de l’activité des molécules sur une cible isolée ne se retrouvait pas toujours sur les parasites. Une faible entrée de la molécule dans la cellule pourrait être une des causes de ce manque de corrélation, comme cela est souvent le cas dans la recherche de molécules actives.Pour valider ou non cette cause, ces travaux de thèse ont eu pour but de concevoir, synthétiser et évaluer de nouvelles sondes fluorescentes qui permettraient de visualiser la pénétration de molécules actives dans des cellules, en nous intéressant en particulier aux parasites responsables de la maladie du sommeil et du paludisme.Notre concept se base sur le principe de la chimie « click », sans catalyseur, impliquant une fonction alcyne et un groupement azoture. Ceci est possible lorsque la fonctionalcyne est insérée dans un cycle tendu comme celui d’un cyclooctyne qui lui confère une plus grande réactivité (Strain-Promoted Alkyne-Azide Cycloaddition).Nous avons synthétisé des dérivés de la dibenzocyclooctynone, une molécule fluorescente décrite pour réagir sans catalyseur avec des azotures, de manière à obtenir des sondes à détection « on-on’ ». Ainsi, sept nouvelles sondes fluorescentes ont été obtenues, dont trois réagissent avec des azotures avec une cinétique adéquate. Les propriétés photophysiques de ces molécules ont été caractérisées et nous avons vérifié qu’elles traversent bien la membrane des protozoaires parasites que nous étudions. La fluorescence n’est observée qu’à l’intérieur du parasite.La détection d’un azoture in cellulo a été vérifiée par HPLC- MS/MS avec une des sondes.Parmi les sept cyclooctynones obtenues, une sonde forme un adduit triazole fluorescent avec une cinétique acceptable, ce qui constitue le premier exemple de sonde « on-on’ » de cette série et une véritable avancée dans la chimie bio-orthogonale
The discovery of new molecules with antiparasitic activity is crucial today to fight against infectious diseases such as malaria and HAT since no vaccine is available to cure these diseases. In our search for new antiparasitic compounds, we observed that activity improvement on an isolated target was not seen on parasite. We suspected an ineffective entry of the molecule into the cell to be one of the reasons for these uncorrelated results.To explore this possibility, this PhD work aimed to design, synthetize and evaluate new fluorescent probes that would allow the visualization of drug entry into parasites responsible for HAT and malaria.Our concept is based on “click” chemistry that can be achieved without catalyst, between an azide and a strained alkyne like cyclooctyne (Strain-Promoted Alkyne-Azide Cycloaddition).We synthetized derivatives of dibenzocyclooctynone, a fluorescent molecule described to undergo SPAAC reaction with azides, in order to obtain “on-on’” detection probes. Seven new fluorescent probes were therefore synthetized, among which three of them displayed adequate SPAAC kinetics. Photophysical properties of these molecules were characterized and their penetration into protozoan cells was demonstrated. Fluorescence was only observed in the parasitic cytosol.In cellulo azide detection was achieved and verified by LC- MS/MS with one of our probes.One out of the seven probes formed a fluorescent triazole adduct, which constitutes the first example of an « on-on’ » probe for this series and a real progress in bioorthogonal chemistry

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23

Nunes, Maria Rita Felício. "Rastreio de formas parasitárias em fezes de cães recolhidas em espaços públicos na cidade de Beja." Master's thesis, Universidade de Lisboa. Faculdade de Medicina Veterinária, 2014. http://hdl.handle.net/10400.5/7580.

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Dissertação de Mestrado Integrado em Medicina Veterinária
A contaminação ambiental por formas parasitárias em espaços públicos de centros urbanos ocorre devido à defecação dos animais (principalmente cães) sem posterior remoção das fezes pelos proprietários, e implica sérios riscos para a saúde animal e pública, no caso de se tratarem de agentes zoonóticos. Neste sentido, foi realizado um estudo com o objetivo de caracterizar o parasitismo com esta origem na cidade de Beja, Portugal. Foram recolhidas 118 amostras de fezes de cães em 13 locais de recolha (parques e jardins) distribuídos geograficamente pela cidade. Todas as amostras foram sujeitas aos mesmos métodos coprológicos: técnica de flutuação (Willis), técnica de Baermann, esfregaços fecais corados com Giemsa e com recurso à técnica de Ziehl-Neelsen modificada. Dez amostras cujo resultado foi duvidoso para presença de Giardia e/ou Cryptosporidium spp. foram posteriormente testadas com kits de imunofluorescência direta. Este estudo demonstrou uma prevalência de 8,5% (10/118) de quistos de Giardia e 0,8% (1/118) de ovos de Uncinaria stenocephala nas amostras analisadas. A amostra positiva a U. stenocephala tinha também presença de quistos de Giardia. Não foram detetadas quaisquer outras formas parasitárias. A prevalência de helmintes neste trabalho foi inferior às registadas noutros estudos nacionais semelhantes. Por outro lado, denota-se uma prevalência relativamente mais elevada de Giardia. Sublinha-se a necessidade de educação da população no sentido da higienização destes espaços, através da remoção das fezes dos seus animais.
ABSTRACT - Parasite screening of canine faecal samples collected in Beja’s public places - Environmental contamination with parasitic agents in public places of urban centres due to animals’ faeces (mostly dogs) is undesirable. It represents a serious risk for animal and public health provided that zoonotic agents are implied. With that in mind, a study was performed aiming at the characterisation of the parasitism with that source in the city of Beja, Portugal. A total of 118 dog faecal samples were collected from 13 different spots, mainly public gardens and parks, geographically scattered over the city. All the samples were analysed by the same methods: flotation technique (Willis), Baermann technique, faecal smear stained with Giemsa and faecal smear stained according to the Ziehl-Neelsen modified technique. Ten dubious samples concerning Giardia and/or Cryptosporidium spp. were also tested with immunofluorescence kits. The present study has revealed 8,5% (10/118) prevalence of Giardia cysts and 0,8% (1/118) prevalence of Uncinaria stenocephala eggs in the analysed samples. The only sample with U. stenocephala eggs, also presented Giardia cysts. No other parasite stages were detected. Helminths prevalence obtained in this study is lower than those reported in similar national studies. On the other hand, there is a relatively higher prevalence of Giardia in this study. One may also highlight the need for education of the population on the hygiene and maintenance of these public areas through removal and disposal of faecal matter.

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Machado, Maria Carolina Santo. "Parasitismo gastrointestinal em cães frequentadores de espaços públicos da freguesia de Mafra, Portugal." Master's thesis, Universidade de Lisboa, Faculdade de Medicina Veterinária, 2019. http://hdl.handle.net/10400.5/18083.

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Dissertação de Mestrado Integrado em Medicina Veterinária
As parasitoses dos animais de companhia são, cada vez mais relevantes, pelo contacto com o ser humano, que tem vindo a aumentar pelos benefícios tanto psicológicos como físicos que promovem nos seus tutores. Muitas destas parasitoses têm potencial zoonótico, podendo causar doença nas pessoas. A presente dissertação teve como objetivo principal determinar a prevalência de vários parasitas gastrointestinais através da colheita de fezes de cão em espaços públicos em várias localidades da freguesia de Mafra. Foram colhidas 130 amostras fecais de cães em 13 locais de recolha, na vila de Mafra e localidades envolventes. Todas foram sujeitas às mesmas técnicas laboratoriais: técnica de flutuação de Willis, técnica de sedimentação natural, técnica de Baermann, esfregaços fecais diretos e após Método da Sedimentação Difásica de Ritchie Modificado corados pela técnica de Ziehl-Neelsen modificada. As amostras de resultado duvidoso para Giardia spp. e/ou Cryptosporidium spp. foram sujeitas a teste utilizando kits de imunofluorescência direta. Este estudo evidenciou uma prevalência global de parasitismo de 14,6% (19/130), sendo que os parasitas mais prevalentes foram Giardia spp. (8,5%), Toxocara canis (2,3%), Cryptosporidium spp (2,3%) e Cystoisospora spp. (0,8%). Não se constatou relação estatisticamente significativa entre exposição solar e presença de parasitas, assim como não houve relação entre a consistência das fezes com a presença de Giardia spp. e Cryptosporidium spp. A prevalência global registada foi inferior a outros estudos, porém alguns dos parasitas encontrados têm potencial zoonótico e, por isso, acarretam preocupação ao nível da saúde pública. É, assim, necessário sensibilizar a população para medidas higio-sanitárias a adoptar, iniciando por simples medidas como a recolha de dejectos dos seus animais de estimação.
ABSTRACT - GASTROINTESTINAL PARASITISM IN DOGS THAT FREQUENT PUBLIC SPACES OF MAFRA, PORTUGAL - Parasitic diseases in pets are becoming more important mainly due to the closest contact between animals and their owners although several benefits, both psychological and physical, are acquired. Many of these parasites have zoonotic potential and may cause problems in the human population. The primary aim of this study was to determine the prevalence of several gastrointestinal parasites through the collection of dog feces in public spaces in Mafra. A total of 130 fecal samples of dogs were collected at 13 collection sites in the village of Mafra and surrounding localities. All of them were subjected to the same laboratory techniques: flotation technique (Willis), natural sedimentation technique, Baermann technique, direct faecal smear and stained with the Ziehl-Neelsen modified technique after the modified Ritchie‘s diphasic sedimentation method. The present study revealed an overall prevalence of parasitism of 14.6% (19/130) being the prevalent parasites Giardia sp. (8.5%), Toxocara canis (2.3%), Cryptosporidium sp. (2.3%) and Cystoisospora sp. (0.8%). There was no statistically significant relationship between sun exposure and presence of parasites, nor was there any relation between the consistency of the feces and the presence of Giardia sp. and Cryptosporidium sp. The prevalence recorded was lower than other existing studies, however some of the parasites found have zoonotic potential and, therefore, are of concern to the public health. Hygienic-sanitary measures should be adopted, such as the collection of pets feces from the soil, being of utmost importance to sensitize the population for the danger of zoonotic diseases.
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Spalenka, Jérémy. "PROTOSCREEN - Screening et identification de molécules actives sur Toxoplasma gondii et autres protozoaires d’intérêt médical et vétérinaire." Thesis, Reims, 2018. http://www.theses.fr/2018REIMM204/document.

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Toxoplasma gondii, Neospora caninum et Plasmodium falciparum sont des parasites protozoaires intracellulaires obligatoires, respectivement responsables de la toxoplasmose, de la néosporose et du paludisme. Les différents traitements mis en œuvre reposent sur une association médicamenteuse. Cependant, des échecs thérapeutiques et des résistances aux traitements ont été décrits. Notre travail a porté sur l’identification de molécules actives isolées par Chomatographie de Partage Centrifuge (CPC) à partir d’extraits d’écorces d’Anogeissus leiocarpus, un arbre d’Afrique de l’ouest connu pour son activité antipaludique, et de dix arbres de la région Champagne-Ardenne. Nous nous sommes penchés, dans un premier temps, sur l’activité antiparasitaire des fractions obtenues à partir d’extrait d’écorce d’A. leiocarpus. La trachélospérogénine E et l’extrait global sans tanin se sont révélés actifs, notamment en inhibant l’invasion des cellules hôtes par T. gondii. Cet extrait a également préservé la survie des souris atteintes de toxoplasmose chronique. Les mêmes composés naturels ont eu un effet contre N. caninum et P. falciparum. Dans une seconde partie, 30 extraits d’écorces de dix arbres de la région Champagne-Ardenne ont été testés sur T. gondii et N. caninum. Les composés responsables de l’activité antiparasitaire présents chez Alnus glutinosa semblent être la bétuline et ses dérivés. Dans la dernière partie, nous nous sommes intéressés à l’activité de 400 molécules de synthèse de la Pathogen Box. Huit d’entre elles ont eu un effet significatif contre T. gondii, dont trois avec une sélectivité importante. Des expérimentations sont toutefois à réaliser pour N. caninum
Toxoplasma gondii, Neospora caninum and Plasmodium falciparum are mandatory intracellular protozoan parasites and are responsible for toxoplasmosis, neosporosis and malaria, respectively. The different treatments used are based on drug combination. However therapeutic failures and drug resistances have been described. Our work focused on the identification of active compounds isolated by Centrifugal Partition Chromatography (CPC) from crude barks extracts from Anogeissus leiocarpus, a West African tree known for its antimalarial activity, and ten trees from the Champagne-Ardenne region. First we studied the activity of the fractions obtained from the crude bark extract from A. leiocarpus. Trachelosperogenin E and the global extract without tannin showed a good activity by inhibiting host cell invasion by T. gondii. The latter was able to preserve mice survival toward chronic toxoplasmosis. These extracts were also active on N. caninum and P. falciparum. In a second part 30 crude barks extracts from ten trees located in the Champagne-Ardenne region were screened on T. gondii and N. caninum. Compounds responsible for the antiparasitic activity found in Alnus glutinosa were especially betulin and its derivatives. In the last part of this study we focused on the antiparasitic activity of 400 synthetic molecules from the Pathogen Box. Eight out of them were significantly efficient against T. gondii, among which three showed an important selectivity. Further experiments must be completed in the case of N. caninum

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Martínez, Flórez Alba. "Drug repurposing of bioenergetic modulators: use in treatment and vaccination of protozoan parasitic diseases." Doctoral thesis, Universitat Autònoma de Barcelona, 2017. http://hdl.handle.net/10803/458381.

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Las leishmaniasis, la tripanosomiasis Americana y Africana, y la malaria son enfermedades parasitarias que constituyen un importante problema de salud global que afecta mayoritariamente a países en desarrollo. El aumento del número de resistencias a sus tratamientos actuales, su toxicidad y la necesidad de asistencia sanitaria para la aplicación de los mismos reflejan la urgente necesidad de desarrollar vacunas eficaces y nuevos tratamientos económicos, fáciles de administrar y resistentes a condiciones de almacenamiento adversas. Basándonos en que estas enfermedades parasitarias comparten requerimientos metabólicos con patologías mejor estudiadas, proponemos el reposicionamiento de fármacos para tratarlas. Bajo esta premisa, seis fármacos de eficacia probada en la investigación contra el cáncer ―dicloroacetato (DCA), 3‐bromopiruvato (3BP), 2‐ deoxi‐D‐glucosa (2DG), lonidamina (LND), metformina (MET) y sirolimus (SIR)― fueron seleccionados por su habilidad para modular rutas metabólicas relacionadas con la producción de energía y proliferación. El objetivo de este estudio fue validar el uso de estos moduladores bioenergéticos para el control de la leishmaniasis visceral, malaria y tripanosomiasis americana y africana como tratamiento o como potenciadores de la protección de una vacuna frente a L. infantum. Para ello, se evaluó la eficacia de estos compuestos en modelos in vitro de cada parasito ―enfermedad de Chagas (Trypanosoma cruzi), tripanosomiasis Africana (Trypanosoma brucei), leishmaniasis visceral (Leishmania infantum) y malaria (Plasmodium falciparum)―. El 3BP y el DCA indujeron una reducción dosis‐dependiente del crecimiento de los amastigotes intracelulares de L. infantum con IC50 de 17.19 μM y 631.5 μM, respectivamente. En el modelo in vitro de T. brucei, todos los compuestos testados, a excepción de 2DG, afectaron a la viabilidad del parásito: DCA (IC50 = 1.24 mM), 3BP (IC50 = 76.57 μM), LND (IC50 = 26.76 μM), SIR (IC50 = 2.14 μM), y MET (IC50 = 17.30 Mm). En el caso de los amastigotes intracelulares de T. cruzi, DCA, 3BP, 2DG, LND, y MET tuvieron efecto parasiticida con valores de IC50 de 27.07 mM, 27.63 μM, 7.27 mM, 78.37 μM, y 18.48 mM, respectivamente. DCA (IC50 = 5.39 mM), 2DG (IC50 = 4.19 mM), LND (IC50 = 209.13 μM), MET (IC50 = 1.32 mM), y SIR (IC50 = 2.50 μM), mostraron efecto antiparasitario sobre trofozoitos de P. falciparum. Estos resultados sugieren que estos fármacos podrían ser útiles para tratar estas enfermedades parasitarias. Sin embargo, cuando los compuestos eficaces en los modelos in vitro fueron administrados en modelos in vivo de roedor para cada una de las enfermedades, ninguno de ellos contribuyó al control de la enfermedad o de la carga parasitaria. Los resultados obtenidos en el modelo de leishmaniasis visceral en hámster revelaron una disminución de la activación del sistema inmune en los animales tratados con DCA y 3BP, lo cual podría haber contribuido al fracaso del tratamiento. Por último, se estudió la capacidad del SIR para potenciar el efecto protector de una vacuna frente a la leishmaniasis visceral en el modelo hámster. Para ello se administró SIR durante la fase de expansión y contracción del sistema inmune producido por una vacuna de DNA portadora de los genes LACK, TRYP, PAPLE22, y KMPII de Leishmania, y se estudió la respuesta frente al posterior desafío con L. infantum. Los resultados muestran que la vacuna de DNA indujo la reducción eficaz de la carga parasitaria en piel (P = 0.0004) y linfonodos (P = 0.0452), lo cual potenció la administración del SIR alcanzándose también protección parasitológica en bazo (P = 0.0004). El estudio de los marcadores inmunológicos en dicho órgano sugiere que la producción controlada de IFN‐γ y el incremento en la expresión de FoxP3 podrían ser los responsables de la protección alcanzada.
Leishmaniases, African and American trypanosomiases and malaria are parasitic diseases that constitute a major global health problem. The increasing number of drug‐resistances to their current treatments, toxicity cases and the health assistance often required for their administration, makes it urgently necessary to develop efficient vaccines for humans and new affordable therapies, easy to apply and resistant to harsh storage conditions. Due to the fact that these diseases share similar metabolic requirements with better studied diseases, we chose drug repurposing as a potentially effective approach against them. With this purpose, six different compounds used in anti‐cancer research —dichloroacetate (DCA), 3‐bromopyruvate (3BP), 2‐deoxy‐D‐glucose (2DG), lonidamine (LND), metformin (MET), and sirolimus (SIR)— were selected according to their ability to modulate energy production and proliferation related metabolic pathways. The aim of this study was to validate the suitability of these bioenergetics modulators for the management of visceral leishmaniasis, malaria and African and American trypanosomiasis as a treatment, or as a preventive tool by enhancing the protective power of a vaccine against L. infantum. The effectiveness of these compounds was first evaluated on in vitro models of each parasite ― Chagas disease (Trypanosoma cruzi), human African trypanosomiasis (Trypanosoma brucei), visceral leishmaniasis (Leishmania infantum) and malaria (Plasmodium falciparum)―. L. infantum promastigotes were not susceptible to these compounds, whereas L. infantum intracellular amastigote growth was dose‐dependently reduced by 3BP (IC50 = 17.19 μM) and DCA (IC50 = 631.5 μM). In the T. brucei in vitro model all the tested compounds, with the exception of 2DG, affected parasite survival with IC50 values of 1.24 mM for DCA, 76.57 μM for 3BP, 26.76 μM for LND, 2.14 μM for SIR, and 17.30 mM for MET. In the case of T. cruzi, DCA, 3BP, 2DG, LND, and MET showed parasite‐killing activity with IC50 values of 27.07 mM, 27.63 μM, 7.27 mM, 78.37 μM, and 18.48 mM, respectively. For P. falciparum DCA (IC50 = 5.39 mM), 2DG (IC50 = 4.19 mM), LND (IC50 = 209.13 μM), MET (IC50 = 1.32 mM), and SIR (IC50 = 2.50 μM), showed antiplasmodial activity. These results reinforce the hypothesis that drugs with proven efficacy in the treatment of cancer by interfering with energy production might be useful in treating threatening parasitic diseases and provide new opportunities for their repurposing. However, when compounds that were effective in the in vitro approach were administered to the in vivo rodent models of these diseases, none of them contributed to disease management or parasite load control. Immunological analysis in the VL hamster model revealed a significant downregulation of immune‐activation in infected animals treated with DCA and 3BP, which may also contribute to treatment failure. In the last chapter of this work, the suitability of sirolimus as an immunomodulatory compound to boost the activity of a preventive vaccine against VL was analyzed. Sirolimus is an already marketed compound that has been described to boost immune protection against different disease models. In our study, Syrian hamsters were treated with sirolimus concomitantly with the administration of a plasmid DNA vaccine carrying the Leishmania genes LACK, TRYP, PAPLE22 and KMPII, and the subsequent response towards a L. infantum challenge was studied. Our results show that the DNA vaccine itself efficiently reduced the burden of parasites in skin (P = 0.0004) and lymph nodes (P = 0.0452), which was potentiated by SIR administration by also inducing parasitological protection in the spleen (P = 0.0004). The study of immune markers in spleen suggests that lower production of IFN‐γ and the concurrent increase of FoxP3+ expression may be responsible for the protection mediated by the DNA vaccine that was potentiated by sirolimus.

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27

Mohammed, Saleem. "Molecular studies on the protozoan parasite Toxoplasma gondii." Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262211.

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Grignard, Lynn. "DNA replication initiation in the protozoan parasite Giardia lamblia." Thesis, St George's, University of London, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.559383.

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In this thesis the Giardia lamblia origin recognition proteins, GiOrc1/cdc6 and GiOrc4 (GiORC) are under investigation. We set out to do a basic molecular characterisation of the GiORC proteins as well as determining origins of DNA replication in the protozoan parasite. The sequences for both GiORC were successfully identified from genome databases and analysed using bioinformatics tools. Furthermore, the GiORC proteins were successfully over-expressed in a bacterial system. In a first strategy, pure protein with or without an affinity tag was used for antibody production, for the use in western blotting, immuno precipitation (interacting partners), chromatin immuno precipitation (identification of origins of DNA replication) and microscopy (protein localisation). Three antibodies against the GiORC were generated. Unfortunately, none of the antibodies recognised the native GiORC. GST-tagged GiOrc4 for GST pull down experiments was used to identify interacting partners, without success. In a second strategy, the GiORC were cloned into Giardia over-expression vectors. Two novel vectors were constructed, pV5.pac and ProtORCtet. Both vectors had not been used previously in the parasite. In addition GiORC sequences were cloned into pGFP.pac, a GFP fusion vector. Six different constructs, three for each GiORC sequence, were generated. In four of the constructs, GiORC/pGFP.pac and GiORC/pV5.pac, expression could not be detected in transgenic cell lines. In ProtOrc4tet, expression of V51HA tagged GiOrc4 was detected by western blot and immuno fluorescence microscopy. In a third strategy, the interaction of GiOrcl/cdc6 and GiOrc4 was shown by yeast two hybrid. We were also interested in the effects of GiORC gene knockdown by RNA interference. The results from the DNA based RNAi vector, however, were inconclusive. In summary, we managed to compile information on the DNA replication proteins m Giardia lamblia and to set up additional tools to further study DNA replication initiation in the parasite.

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29

O'Donoghue, Peter John. "Characterization of parasitic protozoa in Australia /." [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe.pdf.

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30

Taylor, Pamela. "The effects of malaria infection on the blood feeding behaviour of anopheline mosquitoes." Thesis, Keele University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327701.

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Marshall, James Spencer. "Cryptosporidium parvum : detection and distribution in two Yorkshire rivers." Thesis, University of Leeds, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390895.

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32

Biallas, Sandra. "Zur Bedeutung von Endoparasiten bei Chamäleons (Sauria: Chamaeleonidae) aus Wildfängen und Nachzuchten." Doctoral thesis, Universitätsbibliothek Leipzig, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-133462.

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In der vorliegenden Arbeit wurden 212 Kotproben von Chamäleons auf Parasitenstadien und 75 Tierkörper pathologisch sowie bei einem nachgewiesenen Parasitenbefall histopathologisch untersucht. Ziel war es, anhand dieser Untersuchungen das Vorkommen und die Schadwirkungen von Endoparasiten unter Berücksichtigung der Herkunft, des Alters, des Geschlechts und der Chamäleonart zu beschreiben. Von 212 Kotproben wiesen 55,2% Endoparasitenstadien auf. Bei 54,7% der 64 sezierten und auswertbaren Tiere wurden Endoparasiten nachgewiesen. Der Anteil positiver Proben zeigt zwischen Nachzuchten (55,5%) und Wildfängen (54,1%) keinen wesentlichen Unterschied. In Wildfängen konnten häufiger Endoparasiten mit einem indirekten Lebenszyklus ermittelt werden, Nachzuchten beherbergten dagegen öfter Parasiten mit einem direkten Entwicklungszyklus. In den untersuchten Chamäleons konnten regelmäßig Kokzidien der Gattung Isospora und Oxyuriden nachgewiesen werden. Zestoden konnten in der koproskopischen Untersuchung gar nicht aufgefunden werden, wohingegen sie in der pathologischen Untersuchung sporadisch im Darm diagnostiziert werden konnten. Die Häufigkeit des koproskopischen Nachweises von Parasitenstadien bezogen auf die Gesamtzahl der untersuchten Chamäleons stellte sich wie folgt dar: in 30,4% wurden Protozoon gefunden, 21,7% der Tiere waren mit Kokzidien infiziert (davon 78,3% Isospora spp., 13,0% Choleoeimeria spp., 6,5% Eimeria spp., 2,2% Mischinfektion Isospora spp./Choleoeimeria spp.) und 8,5% mit Flagellaten oder Ziliaten. Bei 83,3% der Tiere mit gastrointestinalen Symptomen konnte ein Befall mit Kokzidien der Gattung Isospora nachgewiesen werden. In 38,7% der koproskopischen Untersuchungen konnten Nematoden (65,9% Oxyuriden, 19,5% Askariden/ Heterakiden, 1,4% Rhabdias sp., 2,8% Strongyloides sp., je 0,5 % Spirurida, Heterakiden/Filarien, Oxyuriden/Strongyloiden) und in 2,8% Trematoden (Digenea) aufgefunden werden. Anamnestisch konnten in 35,8% aller Tiere klinische Symptome beobachtet werden, wovon bei 88,2% der erkrankten Tiere ein Endoparasitenbefall nachzuweisen war. Insgesamt 64,1% der sezierten Chamäleons waren mit Endoparasiten befallen, wovon 68,3% Mono- und 31,7% Mischinfektionen beherbergten. In 31,3% der sezierten Chamäleons wurden Nematoden gefunden und der Befall wurde in 55,0% dieser Fälle als hochgradig eingestuft. Es wurden Befallsraten von 25,0% für Strongyloides sp., 23,4% für Askariden/ Heterakiden,15,0% für Filarien, 5,0% für Rhabdias sp., 9,4% für Zestoden, 10,9% für Digenea registriert. In 11,3% der Fälle lagen Mischinfektionen vor. Damit ist ein Endoparasitenbefall bei Chamäleons häufig und kann zu Erkrankungen führen. Die Exposition unterscheidet sich bei Wildfängen und Nachzuchten aufgrund der unterschiedlichen Umgebungsbedingungen. Auch klinisch unauffällige Tiere waren zu 27,8% mit Parasiten befallen, so dass eine klinische Symptomatik nicht zwingend aus einem Parasitenbefall resultiert. Insgesamt betrachtet verdient der Endoparasitenbefall von Chamäleons das Augenmerk von Tierärzten und Tierhaltern und sollte bei augenscheinlich hohem Infektionsdruck zu Gegenmaßnahmen, insbesondere auch einer verbesserten Hygiene, Anlaß geben
In the present study 212 chameleon fecal samples were examined for parasite stages and 75 carcasses were examined histopathologically and pathologically in a proven case of a parasite infestation. The basis of this study was to describe the occurrence and harmful effects of internal parasites considering the origin, age and sex of the chameleons. Of the 212 fecal samples 55.2% showed stages of endoparasites. Parasites were detected at 54.7% of 64 evaluated and dissected animals. The proportion of positive samples shows no significant difference between offspring (55.5%) and wild specimens (54.1%). In wild specimens common internal parasites could be determined with an indirect life cycle, however offspring harbored more parasites with a direct life cycle. In the studied chameleons coccidia as the genus Isospora and Oxyurids were regularly detected. In the coprological study Cestodes could not be found, while in the pathological examination they could be diagnosed sporadically in the intestine. Based on the total number of investigated chameleons the frequency of detection of parasite stages are presented as follows: Protozoa were found in 30.4%, 21.7% of the animals were infected with coccidia (of which 78,3% Isospora spp, 13,0% Choleoeimeria spp., 6.5% Eimeria spp., 2.2% polyinfections between Isospora spp./ Choleoeimeria spp.) and 8.5% with flagellates or ciliates. At 83.3% of the animals with gastrointestinal symptoms coccidia of the genus Isospora were detected. In 38.7% of the fecal examination nematodes were determined (65.9% Oxyurids, 19.5% Ascarids/ Heterakis, 1.4% Rhabdias sp., 2.8% Strongyloides sp., 0.5% Spirurida, Heterakids/ Filariae, Oxyurids/ Strongyloides sp.) and Trematodes in 2.8% (Digenea) were found. The anamnesis showed that clinical symptoms could be observed in 35.8% of all of the animals, whereas endoparasite infestation could be detected inn 88.2% of the affected animals. Overall, 64.1% of the dissected chameleons were infested with parasites, of which 68.3% harbored mono- and 31.7% polyinfections. In 31.3% of the dissected chameleons nematode infestations were found and 55.0% of these cases were classified as severe. Prevalences were registered: 25.0% for Strongyloides spp., 23.4% for Ascarids/ Heterakids, 15.0% for Filaria, 5.0% for Rhabdias sp., 9.4% for Cestodes, 10.9% for Digenea. In 11.3% of the cases mixed infections were reported. Thus, endoparasite infestation is common among chameleons and can lead to diseases. Exposure differs from wild-specimens and captive-bred due to the different environmental conditions. Also, 27.8% of clinically healthy animals were also infested with parasites, which means that clinical symptoms are not necessarily the result of a parasitic infestation. Overall, chameleon endoparasites deserve the attention of veterinarians and pet owners and should be treated promptly when there is a high likelihood of infection or hygiene is of concern

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Vermont, Sarah J. "Proteomic and transcriptomic analysis of the protozoan parasite Neospora caninum." Thesis, University of Liverpool, 2012. http://livrepository.liverpool.ac.uk/11637/.

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Neospora caninum is an economically significant parasitic protozoan causing the disease neosporosis in cattle and dogs. Although a close relative of the zoonotic apicomplexan Toxoplasma gondii, the two organisms exhibit differing host ranges and infection dynamics. T. gondii is a model organism that has been much studied, and a great deal is known about the genes and proteins involved when it invades a host cell. This thesis explores protein expression in the proliferative and invasive tachyzoite stage of N. caninum, in particular the expression of proteins pertaining to the apical complex of organelles; those responsible for entry and establishment within a host cell. Almost 20 % of the predicted proteome has been identified by this analysis to be expressed in the tachyzoite stage, with approximately 50 % of the predicted repertoire of apical proteins being detected. The discovery of differences between these two parasites’ highly syntenic genomes could lead to a better understanding of the process by which T. gondii is able to cause disease in humans, while N. caninum has not been observed to do so. One finding of the recent genome sequencing and annotation project in N. caninum was that a key T. gondii virulence determinant, rhoptry gene 18 (ROP18) was pseudogenised in N. caninum. This finding was investigated further in this thesis to demonstrate that the pseudogenisation of ROP18 was conserved across a range of N. caninum isolates and that in vitro, N. caninum was not able to subvert the murine interferon-gamma (IFN-γ) immune response using ROP18 in the way that virulent T. gondii tachyzoites do. The tissue-dwelling Coccidia have a multi-stage life cycle which includes a latent tissue cyst-encapsulated stage called the bradyzoite. Tachyzoites convert to this more quiescent form when induced by cellular stress, and are able to remain as such for long periods, even years. At times of weakened host immunity, bradyzoites can recrudesce to produce an active infection, which can cross the placenta in a pregnant animal to infect the foetus. This a major route by which N. caninum infection is maintained within cattle herds, therefore the biology of stage conversion from tachyzoite to bradyzoite and vice-versa is of interest to researchers. An RNA-Seq analysis of cultured tachyzoites and bradyzoites identified a marked reduction in rhoptry gene expression, and differing expression profiles of other invasion-related genes from the micronemes and dense granules. Overall, these data identify proteins released from the apical organelles in N. caninum and give an insight into the different repertoires expressed by the tachyzoite and bradyzoite life stages. Furthermore, a comparison between N. caninum and T. gondii predicted apical proteomes indicates that although most genes are shared in a one-to-one orthologous relationship between the two organisms, there are a small number of differences which may turn out to be important to the biology of the parasite, as in the case of ROP18.

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MacFarlane, Ryan Cousteau. "Identification of virulence determinants in the protozoan parasite entamoeba histolytica /." May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.

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GALISTEO, JUNIOR ANDRES J. "Toxoplasma gondii vs radiacao ionizante: estudo da imunidade intestinal em camundongos C57Bl/6j experimentalmente vacinados com taquizoitos irradiados." reponame:Repositório Institucional do IPEN, 2004. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11255.

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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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Tseng, Michelle. "Virulence ecology and evolution in a mosquito and its protozoan parasite." [Bloomington, Ind.] : Indiana University, 2005. http://wwwlib.umi.com/dissertations/fullcit/3204298.

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Thesis (Ph.D.)--Indiana University, Dept. of Biology, 2005.
Source: Dissertation Abstracts International, Volume: 67-01, Section: B, page: 0059. Adviser: Curtis Lively. "Title from dissertation home page (viewed Feb. 21, 2007)."

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Abu, Dayyeh Issa. "Alteration of macrophage signalling and functions by the protozoan parasite «Leishmania»." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66771.

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Parasites of the genus Leishmania are able to secure their survival and propagation within their host by altering key signalling pathways involved in the ability of macrophages (MØs) to directly kill pathogens or to activate cells of the adaptive immune system. One important step in this immune evasion process is the Leishmania-induced activation of host protein tyrosine phosphatase SHP-1. SHP-1 has been shown to directly inactivate JAK2 and Erk1/2, and to play a role in the negative regulation of several transcription factors involved in MØ activation such as: NF-B, STAT-1α, and AP-1. These signalling alterations contribute to the inactivation of critical MØ functions such as the production of IFN-γ-induced nitric oxide (NO), a free radical associated with parasite killing and clearance. In addition to interfering with IFN-γ receptor signalling, Leishmania is able to alter several LPS-mediated responses (e.g. IL-12, TNF-α, NO production) through mechanisms not yet fully understood. A main goal of this study was to better understand the mechanisms used by the parasite to block Toll-like receptor (TLR)-mediated functions. Experiments performed revealed a pivotal role for SHP-1 in the inhibition of TLR-induced MØ activation through binding to and inactivating IL-1 receptor-associated kinase 1 (IRAK-1). We identified the binding site as an evolutionarily conserved ITIM-like motif, which we named kinase tyrosine-based inhibitory motif (KTIM). Further experiments and sequence analysis revealed that several cytosolic kinases other than IRAK-1 possess potential KTIMs, suggesting it could represent a regulatory mechanism widely used by kinases. The final experimental section aimed to explore the differential ability of the two different stages of Leishmania, promastigotes and amastigotes, to alter MØ signalling and function. In conclusion, this work uncovers a new mechanism whereby Leishmania is able
Les parasites du genre Leishmania assurent leur survie et leur propagation par l'altération de voies de signalisation impliquées dans la capacité des macrophages (MØs) à détruire directement les pathogènes ou à activer les cellules du système immunitaire acquis. Une étape critique de ce mécanisme d'inactivation est l'activation par Leishmania de la protéine phosphatase SHP-1 de la cellule hôte. Il a été démontré que la protéine SHP-1 peut inactiver directement JAK2 ainsi que Erk1/2 et joue un rôle dans la régulation négative de plusieurs facteurs de transcription, tels que NF-κB, STAT-1α et AP-1, impliqués dans l'activation des MØs. L'altération de ces voies de signalisation contribue à l'inactivation de fonctions critiques des MØs telle que la production d'oxyde nitrique (NO) induite par l'IFN-γ, un radical-libre impliqué dans l'anéantissement du parasite. En plus d'inhiber les fonctions engendrées par l'IFN-γ, Leishmania est capable d'inhiber de nombreuses fonctions induites par le LPS, incluant la production d'IL-12, de TNF-α et de NO, et cela par des mécanismes encore peu compris. Le but principal de cette étude était de mieux comprendre les stratégies employées par le parasite afin d'inhiber les fonctions induites par les Toll-like receptors (TLRs). Nos résultats révèlent le rôle critique de SHP-1 dans l'inhibition de l'activation des MØs induite par les TLRs, par l'interaction et l'inactivation de la kinase 1 associée au récepteur IL-1 (IRAK-1). Nous avons également identifié le site de liaison qui semble être un motif conservé lors de l'évolution ressemblant à un ITIM, que nous avons nommé motif de kinase à base de tyrosine inhibiteur (KTIM). Des expériences supplémentaires et l'analyse de séquences ont révélées que plusieurs autres kinases cytosoliques autres qu'IRAK-1 possèdent un motif potentiel KTIMs, suggérant que le KTIM pourrait$

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38

Carnaby, Simon. "DNA typing of the human small intestinal protozoan parasite Giardia lamblia." Thesis, Queen Mary, University of London, 1995. http://qmro.qmul.ac.uk/xmlui/handle/123456789/1400.

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At present there is no satisfactory means of typing strains of Giardia lamblia which can explain the broad range of clinical symptoms seen in giardiasis or which can identify genotypes in epidemiological studies. This thesis attempts to address these problems by developing DNA based typing systems sensitive enough to be able to identify many different Giardia genotypes and which may be applied to the organisms found in clinical samples. Four different techniques were assessed for their ability to identify multiple polymorphic loci in the Giardia genome which may be used to genotype and identify isolates of Giardia and upon which the future development of PCR-typing protocols may be based. These techniques included RFLP analysis, random amplified polymorphic DNA (RAPD) analysis, M13 DNA fingerprinting and minisatellite DNA fingerprinting. Minisatellite DNA fingerprinting proved to be the most discriminatory, recognising many hypervariable loci within the Giardia genome which proved useful for in vitro studies on genotypic heterogeneity within Giardia isolates. This approach would require further development in order to be used on in vivo infections where it could directly assess the relationship between genotype and pathogenicity. Therefore the variable repeats recognised on Giardia fingerprints were sought by constructing and screening a Giardia genomic DNA cosmid library. Once cloned these repeats would form the basis of sensitive and specific PCR-based fingerprinting protocols ideal for typing large numbers of infections. The repeat sequences cloned in this way turned out to be Giardia variable surface protein genes with short, imperfect tandem repeats in their 3' flanking DNA. This work has important implications for the future development and use of fingerprinting techniques on Giardia and may be useful in the study of chromosome rearrangement in Giardia which is likely to be involved in surface antigen switching.

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39

Davey, Robert Andrew. "Characterization of nucleoside transport in the intestinal protozoan parasite Giardia intestinalis." Title page, contents and abstract only, 1994. http://web4.library.adelaide.edu.au/theses/09PH/09phd248.pdf.

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Includes copies of other papers co-authored by the author at end of thesis. Includes bibliographical references (leaves 241-265) A rapid sampling technique has been adapted and used to measure nucleoside transport in a human-derived isolate of the intestinal protozoan parasite Giardia intestinalis (syn. G. lamblia)

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40

Ruivo, Mariana Guerreiro Vintém Vieitas. "Parasitas gastrointestinais em répteis de estimação em Barcelona." Master's thesis, Universidade de Lisboa, Faculdade de Medicina Veterinária, 2019. http://hdl.handle.net/10400.5/17612.

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Dissertação de Mestrado Integrado em Medicina Veterinária
Nos últimos anos a popularidade dos animais exóticos aumentou, levando a um desenvolvimento de conhecimentos nas áreas do seu maneio e medicina. Este estudo contribui para esse efeito na área da Parasitologia, tendo sido efetuado um rastreio parasitológico numa população de répteis tidos como animais de estimação na área de Barcelona (Espanha), entre setembro e dezembro de 2017. Foram colhidas 28 amostras fecais, sendo 9 pertencentes a sáurios, 18 a quelónios e 1 a um ofídio. Todas elas foram analisadas através de exames fecais diretos e pelo método de flutuação direta, tendo sido identificadas formas parasitárias em 18 (64% do total de amostras). Em sáurios, foram identificadas coccídias (incluindo Cryptosporidium sp.) em 33% das amostras e oxiurídeos em 56%. Em ofídios, a única amostra analisada apresentou Balantidium sp., Strongyloides sp. e flagelados. Em quelónios, foram detetados oxiurídeos em 28% das amostras fecais analisadas, Nyctotherus sp. e flagelados em 22% das amostras e Balantidium sp. em 11%. Verificou-se que 47% dos animais tinham a desparasitação em dia, enquanto que 21% se encontravam com a desparasitação em atraso. Dos primeiros, 38% apresentaram amostras positivas a parasitas, enquanto que dos em atraso foram encontradas 83% de amostras com formas parasitárias. Para além disto, foram observados parasitas em todas as amostras provenientes dos animais que nunca tinham sido desparasitados (14% dos animais) e ainda 80% de amostras positivas a parasitas em animais cujos tutores não se encontravam informados acerca do estado de desparasitação (18% dos animais examinados). Estes dados remetem para a importância do maneio correto em animais exóticos e no papel imprescindível que o médico-veterinário deve ter na profilaxia das doenças parasitárias e na sua terapêutica.
ABSTRACT - GASTROINTESTINAL PARASITES IN PET REPTILES IN BARCELONA - In the last years, the popularity of exotic animals has increased, leading to a development of knowledge in their husbandry and medicine. This study contributes to a better knowledge on their parasitology, since a parasite screening was performed in a pet reptile population in Barcelona (Spain), between September and December 2017. Twenty-eight faecal samples were collected, 9 of them from lizards, 18 from chelonians and one from a snake. All of them were screened by fresh smears and direct faecal flotations and in 18 of the samples (64%) were positive for parasitic forms. In lizards, coccidian (including Cryptosporidium sp.) were found in 33% of the samples and oxyurids in 56% of them. In Ophidia species, the only screened sample presented Balantidium sp., Strongyloides sp. and flagellates. In chelonians, 28% of the samples had oxyurids, 22% of them had Nyctotherus sp., other 22% had flagellates and Balantidium sp. was identified in 11% of the samples. 47% of the animals were correctly dewormed, but in 21% the deworming program was overdue. From the correctly dewormed animals, 38% had parasites in their faeces and in the overdue ones, 83% of the samples were positive to parasites. Parasites were observed in all samples collected from the 14% of the animals that had never received antiparasitic treatment. In 18% of the animals whose owners were not informed about their antiparasitic treatments, 80% of the samples had parasites. This study shows the importance of the correct husbandry in exotic animals and the crucial role that the veterinarian has in the prevention of parasitic diseases and their therapy.
N/A

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41

Jackson, M. H. "The epidemiology and ecology of toxoplasmosis." Thesis, University of Strathclyde, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381379.

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42

Chalmers, Rachel. "The distribution of Cryptosporidium in livestock and wild animal populations on a Warwickshire farm." Thesis, Coventry University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318154.

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43

Griffiths, Samantha. "Host innate immune interactions with the parasitic protozoan trypanosoma brucei." Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445765.

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44

Yichoy, Mayte. "Lipid uptake and metabolism in the parasitic protozoan giardia lamblia." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2009. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.

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45

Balassiano, Bianca Chiganer Cramer. "Fatores associados ? infec??o natural de c?es por parasitos gastrintestinais." Universidade Federal Rural do Rio de Janeiro, 2007. https://tede.ufrrj.br/jspui/handle/tede/813.

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Infection with gastrointestinal parasites in dogs can be associated with several factors. The aim of this study was to identify these parasites and their frequencies, and to verify the factors associated with infection. From November 2003 to September 2004 five-hundred dogs presented to three veterinary establishments in the municipality of Rio de Janeiro were evaluated. A form was filled for each dog, including information obtained from physical examination and from the interview of the owner, approaching factors related to the dog, the management and the owner. One fecal sample from each dog was examined by centrifugal flotation and centrifugal sedimentation methods and stained by safranin-methylene blue technique. Data obtained from physical exams and interviews, as well as the results of fecal parasitological exams, were submitted to bivariate analysis and, after the selection of significant variables (p=0.05), multivariate analysis was performed, using logistic regression. Gastrointestinal parasites were detected in 46.4% of the dogs. Hookworms (15.2%), ascarids (7.4%), whipworms (5.0%), Dipylidium caninum (0.2%), taeniids (3.0%), Cryptosporidium sp. (26.2%), Cystoisospora sp. (4.4%) and Giardia sp. (2.6%) were observed in the fecal samples. Protozoans (29.6%) were more frequently observed than helminths (23.2%). Age of the animal (p<0.001), access to soil (p<0.001), ambient hygiene (p<0.01) and pro-oestrous (p<0.05) were associated with infections with gastrointestinal parasites. Access to soil (p<0.001), anthelmintic usage (p<0.01), owner s school level (p<0.01), age of the animal (p<0.01), pro-oestrous (p<0.01) and breed (p<0.05) were associated with infections with helminthes. Age of the animal (p<0.001) and ambient hygiene (p<0.01) were associated with infections by protozoans. Frequency of gastrointestinal parasites in dogs was high and infections were associated with factors related to the animal, to the management and to the owner.
A infec??o de c?es por parasitos gastrintestinais pode estar associada a diversos fatores. O objetivo deste estudo foi identificar tais parasitos, observar suas freq??ncias e verificar os fatores associados ? infec??o pelos mesmos. De novembro de 2003 a setembro de 2004, foram avaliados 500 c?es atendidos em tr?s estabelecimentos veterin?rios no Munic?pio do Rio de Janeiro. Um formul?rio foi preenchido para cada c?o, atrav?s de exame f?sico do animal e entrevista com o propriet?rio, abordando fatores inerentes aos c?es e fatores relacionados ao manejo e ao propriet?rio. Uma amostra fecal de cada c?o foi coletada e examinada pelas t?cnicas de centr?fugo-flutua??o em solu??o saturada de a??car e de centr?fugo-sedimenta??o (Ritchie) e corada pela t?cnica de safranina-azul de metileno. Os dados obtidos nos exames f?sicos e nas entrevistas, bem como os resultados dos exames parasitol?gicos de fezes, foram submetidos ? an?lise bivariada e, ap?s sele??o das vari?veis significativas (p=0,05), procedeu-se ? an?lise multivariada, atrav?s de regress?o log?stica. Parasitos gastrintestinais foram detectados em 46,4% dos c?es. Nas amostras fecais observaram-se ancilostom?deos (15,2%), ascarid?deos (7,4%), tricur?deos (5,0%), Dipylidium caninum (0,2%), ten?deos (3,0%), Cryptosporidium sp. (26,2%), Cystoisospora sp. (4,4%) e Giardia sp. (2,6%). Protozo?rios (29,6%) foram mais freq?entes do que helmintos (23,2%). A idade do animal (p<0,001), o acesso ? terra (p<0,001), a higiene do ambiente (p<0,01) e o pr?-estro (p<0,05) estiveram associados ? infec??o por parasitos gastrintestinais. O acesso ? terra (p<0,001), a administra??o de anti-helm?nticos (p<0,01), o grau de escolaridade do propriet?rio (p<0,01), a idade do animal (p<0,01), o pr?-estro (p<0,01) e a ra?a (p<0,05) estiveram associados ? infec??o por helmintos. A idade do animal (p<0,001) e a higiene do ambiente (p<0,01) estiveram associadas ? infec??o por protozo?rios. A freq??ncia de parasitos gastrintestinais em c?es foi alta e as infec??es foram associadas a fatores inerentes aos c?es e fatores relacionados ao manejo e ao propriet?rio.

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46

Monis, Paul T. "Molecular systematics of the protozoan parasite Giardia intestinalis : identification of cryptic species /." Title page, contents and abstract only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phm744.pdf.

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47

Thompson, Heather P. "Detection and characterisation by molecular methods of the protozoan parasite Cryptosporidium parvum." Thesis, University of Ulster, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.414987.

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48

Hall, Martin Leonard. "Metabolic studies of genetically heterogeneous isolates of the protozoan parasite Giardia duodenalis." Thesis, Hall, Martin Leonard (1993) Metabolic studies of genetically heterogeneous isolates of the protozoan parasite Giardia duodenalis. PhD thesis, Murdoch University, 1993. https://researchrepository.murdoch.edu.au/id/eprint/53152/.

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Giardia duodenalis, a protozoan flagellate, is the causative agent of the debilitating disease giardiasis. Variation in symptomatology, course of infection and response to chemotherapy result in difficulties in the diagnosis and treatment of the disease. Though morphologically identical, variation in antigenicity, growth and metabolism between isolates could contribute to variable clinical manifestations. In this study the ultrastructure, metabolism, response to chemotherapeutic agents and the effects, if any, of these, agents on metabolism were investigated in order to determine whether variation amongst these parameters con-elated with predetermined genetic heterogeneity in a number of isolates of G. duodenalis. The aims of this study were to investigate a threefold hypothesis: That genetic variation amongst isolates of G. duodenalis is reflected in i) metabolic variation ii) .variation in sensitivity to chemotherapeutic agents and iii) the effect of these chemotherapeutic agents on the metabolism of isolates. Two genetically heterogeneous isolates of G. duodenalis were selected for observation using transmission electron microscopy during in vitro growth in the presence and absence of glucose. Neither of these isolates was found to contain structures resembling either endosymbiotic bacteria or viruses. Trophozoites of both isolates appeared morphologically normal when cultured in both the absence and presence of glucose, at all stages of growth. The ultrastructure of the two isolates differed in only one aspect: the protrusion of granular material through the disk in isolate BAH 12, but not in the Portland 1 isolate. Metabolic studies were undertaken on three distinct isolates of G. duodenalis, Portland 1, BAC 1 and BAH 12. These isolates were compared to determine whether proven genetic differences were reflected in the carbohydrate metabolism of the parasite. The metabolic endproducts, alanine, acetate and ethanol were assayed during exponential growth of all three isolates. Studies were undertaken in both BIS-33 medium in the presence of glucose, and in serum-free medium where glucose was either present or absent. Results showed that the genetic differences between isolates are associated with quantitative differences in their metabolism. Results of metabolite assays and transmission electron microscopy indicated that glucose and glucose-equivalent glycogen did not appear to be consumed by any of the three isolates. However, the BAH 12 isolate did not increase in cell numbers in the absence of glucose. As the levels of ethanol and acetate produced, in all isolates, were low in comparison to the error involved in glucose and glucose-equivalent glycogen determination, radioisotope studies were undertaken. These studies showed that glucose was being utilized, albeit at extremely low concentrations. The effect of three chemotherapeutic agents, albendazole, metronidazole and chloroquine, on the growth and metabolism of five genetically and metabolically heterogeneous isolates of Giardia was studied. Albendazole was found to have a higher efficacy against the five isolates than either metronidazole or chloroquine. Variation existed between isolates in their sensitivity to all three drugs. However, no correlation was found between sensitivity and either rate of growth or genetic profile of the isolates. All three drugs affected the energy production of isolates by diverting carbon flow from the production of ethanol toward the production of acetate and alanine to varying degrees. The only exception was the BAH 15 isolate. This study has shown that genetic variation amongst isolates of G. duodenalis was reflected in metabolic variation and variation in sensitivity to chemotherapeutic agents between isolates. However, although variation was found, in the effect of chemotherapeutic agents on the metabolism of isolates, this variation could not be correlated with genetic diversity.

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Melo, Sílvia Adelaide Linhares de. "Estudo de enteroparasitoses em pacientes atendidos no Hospital Universitário Lauro Wanderley município de João Pessoa-PB." Universidade Federal da Paraíba, 2015. http://tede.biblioteca.ufpb.br:8080/handle/tede/9075.

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Intestinal parasites diseases are responsible for serious problems in public health, intensely related to health conditions. They generate economic and social harm to the population, reducing their quality of life in developing countries and are also responsible for high mortality rates especially where health is unassisted. This study aided to analyze the association between these infections and clinical variables, haematological and epidemiological and introduce Decision Making considered by Logistic Regression model. This is an observational, analytical, cross-sectional study on the prevalence of intestinal parasites in patients treated at the Gastroenterology clinic of University Hospital Lauro Wanderley, João Pessoa, Paraíba, under the exclusive public service of Brazil’s Unified Public Health System (SUS). The data were collected by the analysis of the records from October 2014 to May 2015. Among the 370 records analyzed, through inclusion and exclusion criteria, totaled 34. The data were organized and tabulated in a spreadsheet and later submitted, through the statistical software R version 2.15.1, to a descriptive analysis and later to an associative analysis between variables as well as the Logistic Regression. The results showed that females were more affected by parasites and the average group-age of subjects was 56 years old and in general from João Pessoa. The helminth was most prevalent when compared to protozoa, being predominantly Schistosoma mansoni. The most widely used methods for fecal examinations were Hoffman and Kato-katz. Among the results of biochemical analysis, most individuals presented levels of leukocytes out of the reference values. Through the relative risk, protective factors were observed between gastrointestinal symptoms, diabetes, hypertension, and diuretic in relation to the presence of the parasite and risk factors between the independent variables and the outcome variable have been gastrointestinal comorbidities, antiparasitic medicine and gastroprotetor.
As parasitoses intestinais são doenças responsáveis por graves problemas na saúde pública, relacionadas às condições sanitárias. Geram danos econômicos e sociais para a população, diminuindo a qualidade de vida em países que estão em desenvolvimento, sendo também responsável por elevados índices de mortalidade, principalmente onde a saúde é desassistida. O objetivo deste estudo é analisar a associação entre estas infecções e variáveis clínicas, hematológicas. Trata-se de um estudo observacional, analítico, sobre a prevalência de enteroparasitoses em pacientes atendidos no ambulatório de Gastroenterologia do Hospital Universitário Lauro Wanderley, município de João Pessoa, Estado da Paraíba, com atendimento público exclusivo no âmbito do Sistema Único de Saúde (SUS). Os dados foram coletados através da análise de prontuários no período de outubro de 2014 a maio de 2015. Os dados foram organizados e tabulados numa planilha e posteriormente submetidos ao software estatístico R versão 2.15.1 a fim de se realizar uma análise descritiva e posteriormente a uma análise associativa entre as variáveis bem como a Regressão Logística. Os resultados mostraram que os indivíduos do sexo feminino foi mais afetado por parasitoses, a faixa etária média dos indivíduos foi de 56 anos e em geral provenientes de João Pessoa. Os helmintos foram mais prevalentes em relação aos protozoários, sendo predominantemente Schistosoma mansoni. Os métodos mais utilizados para exames coproparasitológicos foram o Hoffman e Kato-katz. Dentre os resultados das análises bioquímicas, grande parte dos indivíduos apresentou níveis de leucócitos fora dos valores de referência. Através do risco relativo foram observados fatores de proteção entre os sintomas gastrointestinais, diabetes, HAS, e diurético em relação à presença do parasita e fatores de risco entre as variáveis independentes; e a variável desfecho têm-se comorbidades gastrointestinais, medicamento antiparasitário e gastroprotetor.

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50

Sutton, C. A. "Coccidia : Studies on Â£Tgenetics of the EimeriaÂ£T." Thesis, University of Leeds, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377061.

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Dissertations / Theses on the topic 'Protozoan parasites'

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