• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 229
  • 21
  • 5
  • 4
  • 2
  • Tagged with
  • 264
  • 136
  • 96
  • 87
  • 74
  • 47
  • 44
  • 39
  • 38
  • 34
  • 31
  • 30
  • 29
  • 26
  • 24
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
211

Epidémiologie des protozooses autochtones en PACA : de l'optimisation du diagnostic à l'éco-épidémiologie / Epidemiology of autochtonous protozooses in South-Eastern Franced : from optimisation of diagnosis to eco-epidemiology

Faucher, Benoit 18 December 2013 (has links)
La présence de Leishmania infantum et Toxoplasma gondii en Provence Alpes Côte d’Azur (PACA) est connue depuis plus d’un siècle. Depuis, leur distribution évolue, l'environnement change, les populations touchées se déplacent, et de nouveaux outils techniques et statistiques permettent de mieux les saisir. Une réactualisation de nos connaissances paraissait donc nécessaire. Nous avons d’abord mené une revue de la littérature sur les leishmanioses viscérales. Ensuite, nous avons montré que la leishmaniose muqueuse à L. infantum est marquée par un probable sous-diagnostic, un caractère peu invasif localement et un risque de viscéralisation significatif. Puis une étude éco-épidémiologique a montré que les deux foyers de leishmaniose en PACA impliquaient des biotopes différents, avec une transmission en zone urbanisée dans le foyer marseillais. Enfin, une étude entomologique a confirmé cette transmission urbaine.Nous avons ensuite étudié la toxoplasmose congénitale. D’abord, nous avons essayé d'améliorer les performances techniques du dépistage en montrant l’intérêt pour le diagnostic moléculaire anténatal d’une extraction optimisée de l’ADN parasitaire sur liquide amniotique en utilisant NucliSENS easyMAG plutôt qu’une extraction manuelle utilisant QIAamp DNA minikit. Nous avons également montré l’apport pour le diagnostic néonatal de la toxoplasmose congénitale des IgM ciblant des antigènes de haut poids moléculaire lors de la comparaison des sera des mères et des enfants par Western Blot. Enfin, nous avons rapporté l’évolution sur 16 ans de 127 patients traités pour toxoplasmose congénitale et montré que 19% des enfants présentaient une choriorétinite au cours du suivi. / The epidemiology of Leishmania infantum and Toxoplasma gondii in the Mediterranean basin has been studied for more than a century. Yet, our understanding of these diseases must be updated because ongoing environmental modifications impact their distribution, because affected population change, and because new technical and statistical tools have become available. We first reviewed scientific literature about visceral leishmaniasis. Then, we conducted a clinical study about autochtonous mucosal leishmaniasis due to L. infantum: we showed that this disease was characterized by underrecognition, low local invasiveness, and risk of visceral spreading. Afterwards, an eco-epidemiological study showed that foci of leishmanisis involved different biotopes in South-Eastern France: we specifically highlighted a urban transmission in the Marseille focus. Finally, an entomological survey confirmed this urban transmission and addressed cocirculation with phleboviruses.Then, we studied congenital toxoplasmosis. We contributed to improve technical performances of current screening strategy: we first showed that an optimized extraction of Toxoplasma DNA from amniotic fluid using NucliSENS easyMAG proved superior to manual extraction using QIAamp DNA minikit. Then, we found that comparison of mother and child antibodies that target high-molecular-mass Toxoplasma gondii antigens by immunoblotting improves neonatal diagnosis. Finally, we reported the 16-year long evolution of 127 children congenitally infected with T. gondii and showed that despite early treatment 19% of children finally developed chorioretinitis.
212

Role of the clathrin adaptor complex AP1 and the small GTPase Rab11A in anterograde trafficking in Toxoplasma gondii / Etude du trafic vésiculaire des protéines de rhoptries et micronèmes et de la sécrétion des protéines de granules denses chez Toxoplasma gondii

Venugopal, Kannan 21 December 2016 (has links)
Toxoplasma gondii, l'agent causal de la toxoplasmose appartient au phylum des Apicomplexes. Comme son nom l'indique, le parasite possède un complexe unique d'organites sécrétoires apicaux, les micronèmes, rhoptries et le conoïde, qui jouent un rôle essentiel dans l’invasion de la cellule hôte et la survie du parasite. T. gondii est devenu un modèle populaire de biologie cellulaire et aussi un outil de référence pour l'étude de l’organisation ultra-structurale et des différentes fonctions des autres parasites du phylum Apicomplexa tel que Plasmodium, l’agent causal de la malaria. Cette thèse porte sur deux facteurs essentiels à la survie du parasite : le complexe adapteur de la clathrine AP1 et la petite GTPase Rab11A qui jouent un rôle crucial dans la régulation de certaines voies du trafic intracellulaire de T. gondii. Ainsi, nos travaux ont permis de démontrer un rôle pour AP1 dans le triage différentiel et le transport vésiculaire des protéines MIC et ROP depuis le Trans-Golgi-Network (TGN) et les compartiments endosomaux, respectivement. D’autre part, nos résultats ont révélé un rôle original de AP1 dans la division parasitaire aux stages tardifs de la cytokinèse. Nous avons également identifié un partenaire de AP1, la protéine unique de T. gondii possédant un domaine ENTH : EpsL (pour Espin-Like Protein). Dans les autres Eucaryotes, les protéines epsines sont connues pour activer la formation des vésicules à clathrine en co-opération avec les complexes AP1 et AP2. Nos résultats ont effectivement démontré un rôle de EpsL, similaire à AP1, pour la biogénèse des rhoptries et micronèmes. Nous avons, dans un deuxième temps, examiné les différentes fonctions de la petite GTPase Rab11A. Notre étude par vidéo-microscopie, semble indiquer que Rab11A régule le transport de vésicules depuis le TGN vers la périphérie cellulaire et en particulier, les pôles basal et apical du parasite. Après sur-production de la forme mutée inactive de Rab11A, nous avons démontré un nouveau rôle de la protéine dans la sécrétion des protéines membranaires de surface et dans l'exocytose des granules denses, lors de l'invasion de la cellule hôte mais aussi durant la réplication parasitaire. Finalement, des expériences de pull-down ont permis d’identifier un partenaire intéressant liant Rab11A seulement sous sa forme activée, la protéine unique de T. gondii contenant un domaine HOOK (TgHOOK), que nous avons caractérisée au niveau fonctionnel. Nos résultats suggèrent que TgHOOK régule le transport des vésicules positives pour Rab11A d’une manière dépendante des microtubules. Par conséquent, cette dernière étude a permis de révéler de nouveaux aspects encore inexplorés, bien qu’essentiels, des mécanismes régulant la sécrétion de molécules à la surface parasitaire. / Toxoplasma gondii, the causative agent for the disease Toxoplasmosis belongs to the phylum Apicomplexa. As the name implies, the parasite possesses a unique complex of apical secretory organelles namely the micronemes, rhoptries and conoid, which favor host cell invasion and intracellular survival. T.gondii has become a popular cell biology model and also a reference tool for studying the structure and functions of other important parasites that belong to the same phylum, such as plasmodium, but also higher eukaryotes. The recent advances in dissecting protein trafficking pathways have led to a better understanding of the biogenesis of apical organelles and also to the identification of crucial protein molecules that could determine the fate of the parasite. This thesis focuses on two different molecules, the Clathrin Adaptor complex AP1 and the small GTPase Rab11A that play a crucial role in distinct trafficking pathways of the parasite contributing to a wide range of functions. First, we reveal a role of AP1 in the differential sorting of microneme and rhoptry proteins at the Tran-Golgi-Network and endosomal level, respectively. Accordingly, depletion of AP1 leads to a defect in apical organelle biogenesis. In addition, we reveal an original role of AP1 in parasite division by regulating late stages of cytokinesis. We also identified and studied a partner of AP1, the unique ENTH domain containing protein of the parasite, EpsL (for Espin-like protein). In other Eukaryotes, epsin proteins are well known regulators of clathrin-mediated vesicular budding in co-operation with AP1 and AP2. We demonstrated that EpsL shares similar functions to AP1 in regulating rhoptry and microneme formation. We next worked on the small GTPase Rab11A and defined the dynamics of the protein within the parasite by live imaging. In addition to its known role in cytokinesis, we unravelled a novel function for the molecule in the secretion of surface membrane proteins and the exocytosis of dense granules during both, parasite invasion and replication. Further, pull down experiments on active Rab11A helped us fish an interesting partner molecule, the unique HOOK-domain containing protein that we functionally characterized for the first time in T.gondii. Our data suggest a role of Rab11A in microtubule-dependent transport of vesicules in a HOOK-regulated manner. Therefore, our study provides novel molecular insights into a yet unexplored but essential aspect of constitutive secretion in the parasite.
213

Étude de la réponse immunitaire au cours d’une toxoplasmose oculaire dans des modèles murins / Study of the immunological mechanisms implied in a response to ocular toxoplasmosis in murine models

Rochet, Élise 12 December 2014 (has links)
Toxoplasma gondii est un parasite intracellulaire obligatoire qui infecte plus du tiers de la population mondiale. La toxoplasmose oculaire (TO), qu’elle soit d’origine acquise ou congénitale, est une infection fréquente et redoutable où le pronostic visuel est fortement engagé. La présence du parasite dans le tissu rétinien, ainsi que la réponse immunitaire de l’hôte, qu’il génère participent au développement des lésions. Cependant, les mécanismes physiopathologiques aboutissant à la destruction de la rétine et ceux conduisant à la latence et à la réactivation parasitaires ne sont toujours pas clairement identifiés. De plus, des améliorations des traitements actuels semblent nécessaires afin de traiter au mieux l’ensemble des patients et d’agir également sur la forme latente du parasite et les récidives qui en découlent. Nos travaux sur des modèles murins de la phase aiguë de la TO démontrent que le facteur de virulence parasitaire ROP16 est responsable de l’augmentation de la charge parasitaire et des réponses inflammatoires oculaires Th1 et Th17. De plus, lorsque cette protéine se trouve dans un génotype parasitaire différent de celui d’origine, la pathologie oculaire en est exacerbée. Nous avons également démontré que la cytokine IL-23 participe à la destruction de la rétine et à la multiplication parasitaire. Notre modèle murin de réactivation de la TO met en évidence le rôle protecteur de la voie Th1 à travers l’IFN-γ et celui fortement délétère de la cytokine IL-6. La neutralisation de cette cytokine dans notre modèle diminue la charge parasitaire oculaire ainsi que l’ensemble de la réponse inflammatoire et n’altère en rien la structure rétinienne. Il serait donc très intéressant d’utiliser une thérapie ciblant le récepteur de l’IL-6 afin de contrecarrer les effets des récurrences de la TO. / The obligate intracellular parasite Toxoplasma gondii infects more than one third of the world population. Ocular toxoplasmosis (OT), whether acquired or congenital, is a common and frightening infection which can strongly impair the visual function. OT is considered as a major cause of posterior uveitis and retinochoroiditis is its most common manifestation. The presence of the parasite in the retina as well as the immune response it generates in the host are two factors involved in the development of ocular lesions. However, up to now, the pathophysiological mechanisms leading to the destruction of the retina and those implied in the parasite latency and reactivation have not been clearly identified. Morever, improvements of current treatments are necessary in order to give all patients a better care but also to fight the parasite latent form and relapses they may cause. Our mouse models of OT acute phase have demonstrated that the parasite virulence factor ROP16 is responsible for the parasite load increase and the Th1 and Th17 ocular inflammatory responses. When this protein is in a different genotype than its original one – this has been made possible by recombining strains – the ocular pathology is more severe. We also showed that the IL-23 cytokine was involved in the destruction of the retina and in parasite multiplication. Our mouse model of OT reactivation highlighted the protective role of the Th1 pathway through IFN-γ as well as the highly deleterious IL-6 cytokine. By neutralizing this cytokine in our model, we reduced the ocular parasite load and the global inflammatory response without modifying the retinal structure. It would be very interesting to elaborate a therapy targeting the IL-6 receptor in order to counter the effects of OT recurrences.
214

Identification des facteurs de variation de la prédation exercée par les chats domestiques (Felis silvestris catus) en milieu rural / Identification of factors affecting the predation exert by domestic cats (Felis silvestris catus) in a rural area

Forin-Wiart, Marie-Amélie 19 December 2014 (has links)
La prédation exercée par le Chat domestique (Felis silvestris catus) joue un rôle majeur dans la conservation de certaines espèces proies et la prévention de zoonoses. L'objectif de cette étude était d'identifier les facteurs de variation de cette prédation en milieu rural. L'étude a été conduite dans les Ardennes. La population étudiée comptait 143 individus, dont 44 % de chats de propriétaire (nourris ad libitum, 80 % stérilisés) et 56 % de chats de ferme (peu nourris, non stérilisés). Le DNA metabarcoding et le génotypage ont permis de détecter la fréquence d'apparition des aliments dans des fèces collectées sur le terrain et d'attribuer ces fèces à l'une ou l'autre des catégories de chats. Des individus ont été équipés de colliers GPS et d'accéléromètres tridimensionnels. L'éthogramme accélérométrique d'une séquence de chasse a été construit afin de pouvoir, à terme, relever les événements de prédation et de consommation des proies des individus équipés. Enfin, des variables associées à la prédation ont été mise en relation avec leur sociabilité envers les humains. Les chats ont essentiellement consommé des rongeurs et des aliments d'origine anthropique. En été, les chats de propriétaire chassaient aussi fréquemment que les chats de ferme, tandis qu'en hiver ils chassaient beaucoup moins souvent que ces derniers. Les chats de propriétaire ont de plus petits domaines vitaux que les chats de ferme. Les deux catégories de chats ont un rayon d'action restreint lorsque la pluviométrie est élevée et ont pour proies principales Microtus arvalis et Arvicola terrestris. Le degré de sociabilité des chats vis-à-vis des humains semble affecter leur succès de capture diurne de proies. / The predation exerted by the Domestic cat (Felis silvestris catus) is of special concerns for conservation and prevention of zoonosis issues. This study aims to identify the factors of variation of the predation exerted by cats in a rural landscape. It has been conducted in the Ardennes region. The population studied was composed of 143 individuals, including 44% of house cats (fed ad libitum, 80% sterilized) and 56% of farm cats (poorly fed, not sterilized). DNA metabarcoding and genotyping technics allowed to detect occurrences of food items in field-collected feces and to attribute those feces to one or the other cat categories. Some individuals were equipped with a collar composed by a GPS unit and a tri-axial accelerometer device. The ethogram of a hunting sequence based on accelerometry was constructed to gather information concerning the occurrences of predation and the consumption of the preys by the equipped individuals. Finally, some variables associated to the predation were put in relation with the sociability of cats towards humans. The cats essentially consumed rodents and anthropogenic food. During the summer, the house cats were hunting as frequently as the farm cats, whereas during the winter they were hunting a lot less comparing to the farm cats. Both cat categories have smaller daily movement range during high rainfall periods and their main preys are Microtus arvalis and Arvicola terrestris. The sociability degree of the cats towards humans seems to affect their diurnal stalk success.
215

Padronização e aplicação de ensaio imunoenzimático para detecção de anticorpos IgG contra Toxoplasma gondii na saliva de escolares. / Standardization and application of immunoenzimatic test for detection of IgG antibodies against Toxoplasma gondii in saliva of school.

Miriam de Souza Macre 23 October 2008 (has links)
As zoonoses urbanas, doenças que afetam muitos indivíduos em países tropicais, especialmente crianças, são infecções que podem ser adquiridas pelo homem através do contato com animais de estimação, pela ingestão de carne ou água contaminada. Para sua prevenção, é fundamental a educação para medidas de higiene e profilaxia com relação ao manuseio dos alimentos, animais de estimação e higiene pessoal. Isto poderia ser feito através de ensino intensivo, ministrado por profissionais treinados durante o primeiro ciclo do Ensino Fundamental. No presente trabalho, estudamos este tipo de ensino e a prevalência destas doenças, usando a toxoplasmose como modelo, em 164 alunos do primeiro ciclo do ensino fundamental da Escola Estadual Antonio de Pádua Vieira, com coleta de saliva. Foi desenvolvido ELISA de alta sensibilidade em saliva concentrada por etanol. Após 12 (doze) meses, a fixação do conteúdo foi avaliada por questionário. Havia uma prevalência de 50% de contato com Toxoplasma gondii nessa população, mostrando a relevância do problema. As crianças sob intervenção mostraram fixação do conhecimento, para ambas as fontes principais de contaminação mostrando a importância da intervenção, em comparação com crianças sem intervenção. As crianças sem toxoplasmose mostraram uma melhor eficiência na fixação da informação. Nossos dados sugerem que intervenções curtas têm um grande efeito de fixação de informações em escolares e que a saliva pode ser um material para a detecção de contato com a toxoplasmose. / Urban zoonoses affect large proportion of the population in tropical countries, specially school children. Those infections could be acquired by contact with pets, or ingestion of water or meat contaminated by agents. Education in preventive hygiene measures, as adequate cleaning and cooking are essential in this age group. Intensive teaching during short interventions by trained personal could be effective. Here, we study this type of educational intervention, using toxoplasmosis as a model, in 164 school children in the first years of elementary grades in a public São Paulo school, E.E.P.G. Antonio de Pádua Vieira, with saliva sampling. We had standardize a specific anti T. gondii IgG assay in etanol concentrade saliva. After 12 months, the knowledge of this population was tested by questionnaire. There are a 50% prevalence of contact with T.gondii during the intervention, showing the importance of zoonosis in this group. After one year, most children who assisted the intervention recalled correctly the main transmission ways of the zoonosis, showing fixation by short intervention, as compared to non-intervened shoolchildren of the same age group. Children who had no contact with T.gondii show higher recall proportion. Our data suggest that shorts interventions are effective in the knowledge fixation in schoolchildren and that saliva, a non invasive sampling, could be an alternative material for detection of contact with toxoplasmosis.
216

Identification et caractérisation de BCLA, un antigène spécifique du stade kystique de Toxoplasma gondii et marqueur sérologique potentiel des toxoplasmoses latentes / Identification and characterization of BCLA protein, a Toxoplasma gondii cyst-specific antigen and a relevant serological marker of cyst burden in chronically infected hosts

Dard, Céline 15 October 2018 (has links)
Résumé confidentiel / Résumé confidentiel
217

In-vivo-Modelle der Toxoplasma gondii-Infektion von Huhn und Pute

Geuthner, Anne-Catrin 25 November 2022 (has links)
Einleitung: Toxoplasma (T.) gondii ist ein weltweit verbreitetes Protozoon warmblütiger Tiere und des Menschen. Einer der größten Risikofaktoren einer Infektion des Menschen mit T. gondii ist der Verzehr von rohem oder nicht ausreichend gegartem Fleisch und Fleischerzeugnissen. Geflügel wird als ein bedeutender Zwischenwirt im Lebenszyklus von T. gondii angesehen. Gegenwärtig gibt es aber nur wenige Untersuchungen zur Persistenz und Gewebeverteilung von für den humanen Konsum relevanten Organen und Geweben von T. gondii der Pute (Meleagris gallopavo) und des Haushuhns (Gallus gallus domesticus). Ziel der Untersuchung: Ziel im ersten Teil der vorliegenden Arbeit war es, die Persistenz von T. gondii in verschiedenen Geweben von Huhn und Pute unter Berücksichtigung der üblichen Mastperioden zu ermitteln. Im zweiten Teil der Arbeit wurde unter Simulation der natürlich auftretenden Infektionswege ein Infektionsmodell bei Huhn und Pute unter Nutzung von drei verschiedenen T. gondii-Stämmen etabliert. In diesem Modell wurde der Einfluss der Parameter Infektionsdosis, -stadium und -stamm auf die Verteilung von T. gondii im Gewebe von Huhn und Pute sowie die Serokonversion in den Zielspezies evaluiert. Tiere, Material und Methoden: 108 Puten und 96 Hühner wurden als Eintagsküken eingestallt. Die zur Infektion der Hühner und Puten benötigten Entwicklungsstadien von T. gondii wurden durch Passagen in der Zellkultur (Tachyzoiten), Infektion von Mäusen (Zysten) und durch Infektion von Hauskatzen (Oozysten) gewonnen. Die Evaluierung der Persistenz erfolgte nach intravenöser Gabe von 106 Tachyzoiten des Typ III-Stammes (NED) vier, acht, zwölf und 16 Wochen post infectionem (p.i.) bei Puten und fünf und zehn Wochen p.i. bei Hühnern. Die natürlichen Infektionswege wurden mit der oralen Verabreichung von Gewebezysten (ein Mausgehirn je Tier) oder Oozysten (103, 105 oder 106) eines T. gondii-Stammes der klonalen Linien der Typen II (ME49, Feldstamm CZ-Tiger) und III (NED) über eine Versuchsdauer von acht Wochen bei Puten und fünf Wochen beim Huhn simuliert (n = 6). Zum Versuchsende wurden die Tiere tierschutz-gerecht narkotisiert und durch Dekapitation getötet. Es wurden 16 verschiedene Gewebe (u.a. Gehirn, Herz, Muskulatur, Muskelmagen) entnommen und die Gewebeverteilung der Zysten von T. gondii mittels konventioneller Polymerase-Kettenreaktion (PCR) und magnetic-capture real-time PCR untersucht. Für die serologische Untersuchung von Blutproben wurden ein kinetischer enzyme linked immunosorbent assay (ELISA) und ein Immunfluoreszenzantikörpertest (IFAT) verwendet. Die Blutentnahmen erfolgten am Tag der Infektion und anschließend wöchentlich bis Versuchsende. Die Daten wurden mit dem Kruskal-Wallis-Test und Mann-Whitney-U-Test (Unterschiede Infektionsgruppen in Serokonversion und Gewebeverteilung) und dem Friedman-Test (Organverteilung) analysiert. Signifikante Unterschiede wurden bei einer Irrtumswahrscheinlichkeit von p < 0,05 angenommen. Ergebnisse: In allen 16 untersuchten Geweben von Pute und Huhn konnte nach Infektion mit Tachyzoiten, Zysten oder Oozysten T. gondii-DNA detektiert werden. Nach Tachyzoiteninfektion waren bei der Pute insgesamt 15,9 % der Gewebeproben positiv für T. gondii-DNA, wobei es sich bei 7,8 % der Proben um essbare Gewebe (Oberschenkel-, Unterschenkel-, Brustmuskulatur, Herz, Leber, Muskelmagen) handelte. Zwischen den vier Untersuchungszeitpunkten waren bei der Pute keine signifikanten Unterschiede in der Nachweisrate feststellbar. Bei Hühnern führten die Infektionen mit Tachyzoiten zu vier Nachweisen (2,1 %) von T. gondii, davon in drei Proben fünf Wochen p.i. (Pankreas, Unterschenkelmuskulatur, Retina) und in einer Probe zehn Wochen p.i. (Herz). Ein statistischer Vergleich der Untersuchungszeitpunkte war aufgrund der wenigen positiven Befunde nicht möglich. Die Infektionen mit Zysten oder Oozysten ergaben hohe Nachweisraten in Gehirn (Pute 44,4 % - 64,1 %, Huhn 18,8 % - 38,5 %) und Herz (Pute 5,6 % - 28,2 %, Huhn 31,3 % - 53,8 %). sowie Muskelmägen (Pute 16,7 % - 20,5 %, Huhn 6,3 % - 25,6 %). Bei Infektionen mit Oozysten der Typ II-Stämme stiegen mit der Infektionsdosis auch die Positivraten bei Huhn und Pute. Infektionen mit dem Typ III-NED-Stamm führten zu signifikant niedrigeren Nachweisraten bei Huhn (1,9 %) und Pute (5,7 %) als solche mit den Typ II-Stämmen ME49 (Huhn: 16,4 %, Pute: 18,8 %) und CZ-Tiger (Huhn: 27,8 %; Pute: 11,7 %). Eine Serokonversion trat bei Huhn und Pute ab einer Woche p.i. auf. Mit steigender Dosis von Typ II-Stamm Oozysten war bei beiden Spezies eine frühere Serokonversion nachweisbar. Schlussfolgerungen: Das in der vorliegenden Arbeit etablierte In vivo-Modell ist geeignet, Hühner und Puten auf verschiedenen Wegen mit T. gondii zu infizieren. Die Nachweise von T. gondii-DNA in Organen und Geweben, auch in zum menschlichen Verzehr genutzten, bei Hühnern bis zu fünf Wochen p.i. und Puten bis zu 16 Wochen p.i. zeigen eine Persistenz von T. gondii bis mindestens zur Schlachtreife an. Das Risiko einer Infektion des Verbrauchers mit T. gondii beim Verzehr von nicht ausreichend gegartem Geflügelfleisch oder Geflügelfleischerzeugnissen oder dem Umgang mit rohem Fleisch oder sonstigem Gewebe von Geflügel ist demzufolge grundsätzlich gegeben. Die Rolle von Geflügel oder anderen Vögeln in der Epidemiologie der humanen Toxoplasmose ist aber noch nicht gänzlich klar und verdient weitere Aufmerksamkeit.:1. Einleitung 2. Literatur 2.1. Toxoplasma gondii 2.1.1. Erreger 2.1.2. Entwicklungszyklus 2.1.3. Genetik und Virulenz 2.1.4. Nachweismöglichkeiten 2.1.4.1. Bioassay 2.1.4.2. Polymerase-Kettenreaktion 2.1.4.3. Serologie 2.2. Bedeutung für den Menschen 2.2.1. Humane Toxoplasmose 2.2.2. Risikofaktoren 2.3. Bedeutung der Toxoplasmose des Geflügels 2.3.1. T. gondii-Infektion des Huhnes 2.3.2. T. gondii-Infektion der Pute 3. Publikationen 3.1. Publikation 1 3.2. Publikation 2 3.3. Publikation 3 3.4. Publikation 4 4. Diskussion 4.1. Klinische Beobachtungen 4.2. Serologische Untersuchungen 4.2.1. Serokonversion und Infektionsstadium 4.2.2. Serokonversion und Infektionsdosis 4.2.3. Serokonversion und Infektionsstamm 4.3. Gewebeverteilung 4.3.1. Persistenz von T. gondii im Gewebe von Geflügel 4.3.2. Prädilektionsstellen bei Hühnern und Puten 4.3.3. Einflussfaktoren auf die Organverteilung 4.3.4. Einfluss der Methodik 4.4. Weitere Einflussfaktoren auf die Untersuchungen 4.5. Zusammenfassung der Diskussion 5. Zusammenfassung 6. Summary 7. Literaturverzeichnis Danksagung
218

Desenvolvimento de teste imunocromatográfico para detecção de anticorpos IgG anti-toxoplasma gondii. / Immunochromatographic assay for the detection of anti-Toxoplasma gondii IgG antibodies

Mioranza, Sônia de Lucena 02 February 2010 (has links)
Sendo uma patologia prevenível e tratável, o importante na toxoplasmose congênita é o diagnóstico precoce, fundamental para intervenção terapêutica imediata. Em Cascavel-PR a soroepidemiologia da toxoplasmose foi avaliada em 334 soros de gestantes, com prevalência de 54% e risco de 2,5%aa de infecção aguda. Para monitorar e instrumentar o pré-natal através da triagem de gestantes soronegativas por acompanhamento mensal foi desenvolvido um teste imunocromatográfico para detecção de anticorpos IgG anti-Toxoplasma gondii. (TIC-toxo). Conjugados de ouro coloidal com diferentes extratos antigênicos do agente e os reagentes controle e teste da reação foram preparados e avaliados por imunofiltração e controles intraexperimentais, incluindo microscopia eletrônica, sendo. selecionados na padronização o conjugado de ouro de 6nm recoberto com 2,5 ug/A 540nm de ouro de extrato antigênico alcalino de T. gondii, na linha teste da membrana, a Proteína A de S.aureus e na linha controle, o anticorpo anti-T. gondii,. No ensaio foram testadas 70 amostras de soro em duplicata, sendo 35 reagentes e 35 não reagentes, comparando com ELISA comercial, ELISA in house e IFI. Sensibilidade, especificidade, valor preditivo positivo, valor preditivo negativo e eficiência do TIC-Toxo foram, respectivamente: 88,6% (IC 72,3-96,3), 80,0% (IC 62,5-90,9), 81,6% (IC 65,1-91,7), 87,5% (IC 70,1-95,9) e 0,8429, havendo concordância e reprodutibilidade (Kappa=0,712171) entre o TIC-toxo e os métodos clássicos. O teste desenvolvido é rápido, de baixo custo, de fácil execução em única etapa para uso ambulatorial, precedendo a confirmação laboratorial, na triagem de gestantes ou grupos específicos, permitindo especialmente, o manejo adequado das gestantes de Cascavel em risco de toxoplasmose congênita. / As preventable and treatable condition, the main goal in congenital toxoplasmosis is early diagnosis, essential for adequate therapy. We study seroepidemiology of toxoplasmosis in 344 sera samples from pregnant women of Cascavel, PR, Brazil. By consistent serology, we demonstrate 54% prevalence and a 2.5% risk of acute infection/year, using several approaches. For supply the antenatal office care, it would be important a quick immunochromatographic assay for detection of anti T.gondii</I. IgG antibodies (TIC-Toxo), to be applied in the follow up of pregnant women at risk of infection. To develop the TIC-Toxo assay, we evaluate and standardize the gold particle conjugate adsorbed with several types of tachyzoite extracts, aside to specific reagents for the control and test area of the strip test, by immunofiltration assays, with several quality control steps including electron microscopy. Those analysis provide data for defining the reagents for mass production of TIC-Toxo, constructed with 6 nm colloidal gold conjugate recovered with 2.5ug/A540 of alcaline extract from T.gondii tachyzoites, with S.aureus Protein A at test dot and anti-T.gondii antiserum at control dot. Seventy sera samples were blind tested, 35 positive and 35 negative, comparing to ELISA and IFA assays. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy were respectively: 88,6% (IC 72,3-96,3), 80,0% (IC 62,5-90,9), 81,6% (IC 65,1-91,7), 87,5% (IC 70,1-95,9) e 0,8429, with good agreement of TIC-Toxo and other assays (Kappa=0,712171), with good intra and inter test reproducibility. This TIC-Toxo is a quick, low cost, one step assay and easily performed, to be used for prenatal ambulatory diagnosis of toxoplasmosis, preceding the laboratorial confirming diagnosis and allowing adequate care of pregnant women or others selected groups at risk of acute toxoplasmosis and fetal congenital disease, specially at Cascavel-Pr.
219

Imunidade humoral na toxoplasmose ocular. / Humoral immune response in ocular toxoplasmosis.

Tsukuda, Lilia Rios 07 December 2007 (has links)
T. gondii é um protozoário amplamente disseminado pelo mundo que pode causar doença em animais e humanos. A evolução e a gravidade da doença dependem de características genéticas do parasita e do hospedeiro. A prevalência varia geograficamente, em Erechim, RS, 88% da população é soropositiva e 18% destes apresentam toxoplasmose ocular (TO). A resposta imune humoral contra T. gondii é persistente em todas as fases da infecção. O objetivo deste retrospectivo estudo foi correlacionar a imunidade humoral e a resposta contra peptídeos cepa-específicos com a gravidade da TO em pacientes de Erechim. 327 amostras de soro foram testadas (ELISA) para a pesquisa dos isótipos específicos e contra peptídeos cepa-específicos de regiões polimórficas (GRA6 e GRA7) do parasita. Nossos resultados sugerem que IgG2 e IgG3 estão associados à infecção adquirida recente, porém não há associação entre os isótipos e a evolução clínica da TO. Entretanto, embora seis diferentes sorotipos infectem estes pacientes, a gravidade da TO está associada a um novo padrão sorotípico (Atípico D). / T. gondii is a widespread protozoan parasite that is associated with a large spectrum of diseases in both humans and animals. The progression and severity of disease is quite variable and presumably due to some combination of host and parasite genetics. Prevalence varies with geography. In Erechim, Brazil, it is 88% prevalent and is related with a high incidence (18%) of ocular toxoplasmosis (OT). Humoral immune response against the parasite is effective. The aim of this retrospective study was to correlate the humoral immunity and response against the strain-specific peptides with the severity of the TO in Erechim`s patients. 327 sera were evaluated by ELISA to isotypes, IgG avidity and serotyped using strain-specific polymorphic peptides (GRA6 and GRA7). Our results suggest that IgG2 and IgG3 were associated with recent acquired infection. However, there is no association between isotypes and clinical evolution of OT, and also 6 different serotype-strains were detected in this population, but only one of these (Atypical D) was strongly associated with severe OT.
220

Toxoplasmose suína: contribuição para o estudo epidemiológico / Not available

D\'Angelino, Jose Luiz 26 August 1983 (has links)
O presente trabalho foi realizado visando: a) o acompanhamento da dinâmica da evolução dos anticorpos revelados pelas provas de imunofluorescência indireta (IFI) e hemaglutinaçâo (HA); b) o estudo da concordância de resultados das duas provas, mediante a estatistica Kappa e da co-positividade e co-negatividade; c) e a avaliaçâo da prevalência da infecção toxoplásmica em rebanhos suínos pertencentes a diferentes modalidades de exploraçâo zootécnica (intensiva e semi-intensiva) pelas provas de IFI e HA. Foi realizada a inoculaçâo experimental de 20 suínos com a forma infectante de taquizoitos do Toxoplasma gondii e mantidos 7 outros como controle. Os animais ficaram sob observaçâo durante um período de 84 dias (12 semanas). No 7º dia pós-inoculação, 74,0% dos suínos apresentaram anticorpos revelados pela prova de IFI, enquanto que HA detectou em 21,0% dos animais. Os anticorpos persistiram durante todo o periodo de observação, com a primeira prova revelando títulos mais altos. Ambas as provas apresentaram sensibilidade e especificidade de 100%, a partir do 10º dia, já que todos os animais inoculados revelaram anticorpos, enquanto que os do grupo controle permaneceram negativos durante todo o experimento. No estudo de concordância das duas provas foram examinados soros de 273 suínos, abatidos em matadouros, verificando-se que o grau de concordância medido por Kappa foi de 69,24%. O índice de co-positividade de HA em relação à IFI foi de 72,78% e o de co-negatividade, l00%. A prevalência da infecção, considerando todas as idades em rebanhos suínos segundo a prova de IFI, foi de 54,0% para o sistema de criação intensiva e 49,2% para a criação semi-intensiva, enquanto que para a prova de HA foi de 46,6% e 42,7%, respectivamente. Os valores das prevalincias observadas segundo o tipo de criação (intensiva e semi-intensiva) não diferiram estatisticamente. No que se refere às taxas de infecção toxoplásmica segundo as diferentes idades estudadas, observou-se na queda dos valores do grupo de até 2 meses de idade para o de 2 a 4 meses, para a partir deste haver um incremento com o progredir da idade. / The present work was done aiming: a) the following of the dynamics of antibodies response revealed by Indirect Fluorescent Antibodies (IFA) and Hemagglutination (HA) techniques; b) the study of the agreement between the results of the two tests by means of Kappa statistics as well as copositivity and co-negativity índices; c) the evaluation of the prevalence of toxoplasmic infection in swine herds belonging to different types of pig-raising (intensive and semi-intensive) by the IFA and HA tests. For the experimental infection study, a group of twenty swines were inoculated with the infecting form of tackyzoites of Toxoplasma gondii; and seven additional ones were maintained as the control group. The animals were observed during a period of 84 days (12 weeks). On the 7th day post-inoculation, 74,0% of sera of experimentally inoculated animals presented antibodies for the IFA technique, while HA revealed antibodies in 21,0%. With the infected group, antibodies were detected through all period of observation, but the IFA technique showed higher antibody titers than the HA. Both methods presented 100% of sensitivity and specificity, starting from the 10th day of observation. All animals of the control group were negative for the antibody detection during the observed period. Two hundred and seventy three swine sera collected from a slaughter-house were used for the study of the agreement between the two tests. Kapps statistics showed 69,24% of agreement and the rate of co-positivity of HA test in relation to the IFA test was 72,78, and the rate of conegativity was 100%. The prevalence rates considering all the ages in the swine herds tested according to the method of IFA was 54,0% for the intensive-raised animals and 49,2% for animals of the semi-intensive system, while the HA test showed respectively 46,6% and 42,7%. The prevalence rates observed according to the type of pig-raising (intensive or semi-intensive) did not differ statistically. As for the rates of the toxoplasmic infection according to the different ages studies, it was observed a decrease in the values from group \"until 2 months\" in relation to the group \"2 to 4 months\", and then an increase with the advance of age.

Page generated in 0.0427 seconds