Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-09-09T11:44:34Z No. of bitstreams: 1 hugovieirafajardo.pdf: 1531404 bytes, checksum: f5fe49445c6f2c8dfc323eea58325b41 (MD5) / Approved for entry into archive by Diamantino Mayra (mayra.diamantino@ufjf.edu.br) on 2016-09-13T15:40:16Z (GMT) No. of bitstreams: 1 hugovieirafajardo.pdf: 1531404 bytes, checksum: f5fe49445c6f2c8dfc323eea58325b41 (MD5) / Made available in DSpace on 2016-09-13T15:40:16Z (GMT). No. of bitstreams: 1 hugovieirafajardo.pdf: 1531404 bytes, checksum: f5fe49445c6f2c8dfc323eea58325b41 (MD5) Previous issue date: 2011-03-01 / A toxoplasmose é uma zoonose mundialmente disseminada causada pelo protozoário intracelular obrigatório Toxoplasma gondii. Os felídeos são os únicos hospedeiros definitivos, pois neles ocorre a reprodução sexuada e eliminação de oocistos pelas fezes, enquanto que o homem, outros mamíferos e as aves são hospedeiros intermediários e não possuem esta característica, transmitindo a doença por via congênita ou principalmente quando sua carne é ingerida na alimentação por outros animais. O hábito alimentar do brasileiro e a grande importância econômica do país no cenário internacional da pecuária bovina de corte, objetivaram este trabalho a realizar um estudo soroepidemiológico da toxoplasmose bovina na Zona da Mata Mineira e detecção dos fatores de risco de infecção e disseminação do parasito entre os bovinos criados para o abate. Para isso, foram coletadas 1200 amostras de sangue de bovinos para análise sorológica, utilizando-se a técnica de reação de imunofluorescência indireta (RIFI); também foi feita uma visita às propriedades rurais de onde provinham estes animais abatidos, e realizado um questionário epidemiológico com os produtores rurais destes estabelecimentos, com perguntas que esclareciam algumas dúvidas sobre o manejo e condições sanitárias das propriedades em questão que poderiam influenciar e servir como fatores de risco no ciclo deste parasito. Encontramos uma prevalência de 2,68% de animais positivos analisados para anticorpos anti-T.gondii da classe IgG, e com relação aos fatores de risco, os que envolvem a atuação de um médico veterinário na criação, sinais clínicos da doença e presença de felinos nas propriedades obtiveram um destaque nos resultados encontrados como fatores com consideráveis níveis de significância estatística e correlação positiva com a soropositividade dos animais. / The toxoplasmosis is a zoonose worldwide disseminated, caused by the obligatory intracellular protozoan Toxoplasma gondii. The felines are the only definitive hosts, because in this host the parasites can reproduce sexually and eliminate oocistos through the host feaces. The man kind, like other mammals, and also the birds are intermediary hosts, transmitting the toxoplasmosis congenitally or mainly when its meat is ingested by other animals. Brazilian’s food habit and the great economical importance of the country in the international cattle field are important factors that justify the investigation about the prevalence of toxoplasmosis in cattle. Therefore, the purpose of this work was to realize a seroepidemiologic study of the bovine toxoplasmosis at the Zona da Mata, in Minas Gerais. Looking forward to elucidate the risk factors of infection and insemination from the parasite in between the cattle designated to slaughter. For that, 1200 samples of cattle blood were collected for the serological analysis, using the indirect reaction of imunofluorescence technique (IRIF); visits to the rural properties where those animals came were also realized and on those occasions the rural producers from these properties responded to a epidemiological questionnaire with questions about the properties managing and sanitary conditions, that could act as risk factors of infection by T. gondii. Among the 1195 animals tested for IgG anti-T. gondii, using the IRIF technique 32 presented themselves seropositives, which means 2,68% of prevalecence. Bovines from 53 properties located in the Zona da Mata Mineira were analized. From these 53 properties, 17 (30,07%) showed one or more serologically positives animals for T. gondii. With respect to risk factors, the ones that involve the actuation of a Veterinary Doctor in the raising, clinical signs of the disease and the presence of felines in the properties got a highlight on the results found as factors with considerable levels of statistic significance and positive relations to the seropositivity of the animals.

Orientador: Cláudio Lúcio Rossi / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-19T13:51:41Z (GMT). No. of bitstreams: 1 Nascimento_FernandaSantos_D.pdf: 5313856 bytes, checksum: fd526ebe03ae5465c13afe95ffe8df9a (MD5) Previous issue date: 2012 / Resumo: A neurotoxoplasmose é considerada uma grave complicação em pacientes com comprometimento do sistema imune e em crianças congenitamente infectadas pelo Toxoplasma gondii. O presente estudo abordou três aspectos da neurotoxoplasmose, o diagnóstico molecular, a resposta imune e a relação desta infecção com transtornos mentais. Com relação ao diagnóstico molecular, a eficiência das técnicas de nested-PCR (nPCR) e PCR convencional (PCRc) em detectar DNA do T. gondii foi avaliada em nove amostras de líquido cefalorraquidiano (LCR) de pacientes com neurotoxoplasmose, cinco amostras de LCR de pacientes com outras desordens neurológicas (dois com neurocriptococose, dois com neurosífilis e um com neurocisticercose) e amostras artificiais contendo diferentes concentrações do parasito. A nPCR foi positiva em todos os nove pacientes com neurotoxoplasmose, enquanto a PCRc foi positiva em somente cinco casos. As duas técnicas de PCR foram negativas em LCR de pacientes com outras desordens neurológicas. Nas amostras artificiais, a concentração de taquizoítos detectada por nPCR foi dez vezes menor do que aquela detectada por PCRc. Para avaliar a resposta imune, anticorpos das subclasses da IgG anti-T. gondii foram pesquisados em 19 amostras de LCR de pacientes com neurotoxoplasmose, utilizando ELISA padronizada com uma preparação antigênica de cistos do parasito. Os anticorpos IgG1, IgG2, IgG3 e IgG4 foram detectados em 84,2%, 73,7%, 36,8% e 36,8% dos pacientes, respectivamente. Não foram encontradas diferenças significativas entre as sensibilidades e as médias das absorbâncias das reações ELISA para IgG1 e IgG2, porém, as sensibilidades e as médias das absorbâncias das reações para essas duas subclasses foram significativamente maiores do que as encontradas nas reações ELISA para IgG3 e IgG4. A associação entre toxoplasmose e transtornos mentais foi investigada comparando as prevalências e/ou as concentrações dos anticorpos IgG, IgM e IgA anti-T. gondii, detectados por reações imunoenzimáticas, em amostras de soro de 41 pacientes com esquizofrenia, 38 pacientes com transtornos do humor e 95 voluntários sadios. Os anticorpos IgG foram detectados em 43,9% dos pacientes com esquizofrenia, 52,6% dos pacientes com transtornos do humor e 28,4% dos voluntários sadios. A prevalência da IgG e as concentrações desse anticorpo nos pacientes com transtornos do humor foram significativamente maiores do que as encontradas em voluntários sadios (p=0,0204 e p=0,0059, respectivamente). Por outro lado, não foram encontradas diferenças significativas nesses dois parâmetros entre pacientes com esquizofrenia e voluntários sadios ou entre os pacientes com esquizofrenia e transtornos do humor. Os anticorpos IgA foram detectados em um paciente (2,6%) com transtorno do humor e em um (1,1%) voluntário sadio, enquanto os anticorpos IgM foram detectados em dois pacientes (5,2%) com transtornos do humor. O presente estudo indica que a nPCR pode ser uma ferramenta potencialmente útil para a confirmação diagnóstica da infecção do sistema nervoso central pelo T. gondii e sugere que esse parasito poderia ser um dos possíveis fatores causais dos transtornos do humor. Estudos adicionais são necessários para compreender melhor a fisiopatologia da neurotoxoplasmose e sua associação com outras doenças / Abstract: Neurotoxoplasmosis is considered a serious complication in patients with an impaired immune system and in children congenitally infected by Toxoplasma gondii. The present study addressed three aspects of neurotoxoplasmosis, namely, the molecular diagnosis, the immune response and the relationship of this infection to mental disorders. With regard to molecular diagnosis, the ability of nested-PCR (nPCR) and conventional PCR (cPCR) to detect T. gondii DNA was assessed in nine cerebrospinal fluid (CSF) samples from patients with neurotoxoplasmosis, five CSF samples from patients with other neurological disorders (two with neurocryptococcosis, two with neurosyphilis and one with neurocysticercosis) and artificial samples containing different concentrations of the parasite. The nPCR was positive in all nine patients with neurotoxoplasmosis whereas the cPCR was positive in only five cases. Both PCR procedures were negative in CSF from patients with other neurologic disorders. In the artificial samples, the tachyzoite concentrations detected by nPCR were ten times lower than those detected by cPCR. To assess the immune response, 19 CSF samples from patients with neurotoxoplasmosis were screened for IgG subclass antibodies to T. gondii using an ELISA standardized with an antigenic preparation from parasite cysts. IgG1, IgG2, IgG3 and IgG4 antibody subclasses were detected in 84.2%, 73.7%, 36.8% and 36.8% of the patients, respectively. There were no significant differences in the ELISA sensitivities and mean absorbances for IgG1 and IgG2, whereas the sensitivities and mean absorbances for these two IgG subclasses were significantly higher than for IgG3 and IgG4. The association between toxoplasmosis and mental disorders was investigated by comparing the prevalences and/or the concentrations of anti-T. gondii IgG, IgM and IgA antibodies screened by immunoenzymatic reactions in serum samples from 41 patients with schizophrenia, 38 patients with mood disorders and 95 healthy volunteers. IgG antibodies were detected in 43.9% of patients with schizophrenia, 52.6% of patients with mood disorders and 28.4% of healthy individuals. The prevalence of IgG and the concentration of this antibody in patients with mood disorders were significantly greater than in healthy volunteers (p=0.0204 and p=0.0059, respectively). In contrast, there were no significant differences in these two parameters between patients with schizophrenia and healthy volunteers, or between patients with schizophrenia and patients with mood disorders. IgA antibodies were detected in one patient (2.6%) with mood disorders and in one (1.1%) healthy volunteer, whereas IgM antibodies were detected in two patients (5.2%) with mood disorders. The present study indicates that nPCR may be a potentially useful tool for the diagnosis of T. gondii infection of the central nervous system and suggests that this parasite could be a possible cause of mood disorders. Further studies are necessary to improve our understanding of the physiopathology of neurotoxoplasmosis and its association with other diseases / Doutorado / Ciencias Biomedicas / Doutor em Ciências Médicas

Made available in DSpace on 2014-08-20T14:31:31Z (GMT). No. of bitstreams: 1 dissertacao_beatris_cademartori.pdf: 636391 bytes, checksum: 43565196211ab5284ee321f2b82e0430 (MD5) Previous issue date: 2007-06-28 / The toxoplasmosis acquired during pregnancy of benign course in imunocompetentes patients and asymptomatic in 85% of the cases may infect the fetus and result in congenital infection. Although most of the newborns do not present symptoms or clinical signs, there may be sequelae during the childhood and adult life, being the corioretinitis the most frequent one. Among the strategies to prevent congenital toxoplasmosis we can find the education for health and the preconception trial, which aim is to reduce the exposition to the risk factors that may lead to an infection by T. gondii, to detect and to treat acute infection in pregnant woman. The aims of this study were to evaluate the prevalence and risk of congenital transmission by Toxoplasma gondii, through serological analysis of the pregnant women and also through their knowledge about the zoonose transmission routes, to check the possible association between the soropositivity of the pregnant women and their exposition to the infection risk factors, and also to compare the Chemiluminescence and Indirect Immunofluorescence techniques in the diagnosis of the toxoplasmosis in the studied sample. A transversal study was conducted, with 425 pregnant women who were attending prenatal care in public health centres of Pelotas (RS-Brazil), during the period of May to November 2006. It was verified a T. gondii soroprevalence of (IgG) 54,8% and it was not detected the presence of IgM antibodies. The analysis of the risk factors showed a significant association (p<0.05) between the soropositivity of the pregnant women and their age, the handle of raw meat, the intake of raw vegetables, raw or undercooked meat and raw or nonpasteurized milk and direct contact with the soil. The Logistic Regression Model confirmed the above associations to the intake of raw or undercooked meat (OR=1.85) and to the direct contact with the soil (OR=2.67). The interaction with cats did not present a significant association with the T. gondii soropositivity patients. It was observed that the pregnant women who were interviewed did not know much about the disease and its main sources of infection. The Chemiluminescence technique proved to be an adequate one in the routine diagnosis of the T. gondii infection as, besides being a practical technique, it showed results comparable to the ones of the Indirect Immunofluoresence, sensibility, specificity and accuracy. The results indicate the necessity of implementing T. gondii primary prevention programmes for the pregnant women who as a way of reducing the risks of congenital toxoplasmosis. / A toxoplasmose adquirida durante a gestação, de curso benigno em pacientes imunocompetentes e assintomática em 85% dos casos, pode ser transmitida para o feto e resultar em infecção congênita. Embora maioria dos recém- nascidos não apresente sintomas ou sinais clínicos, pode evoluir para seqüelas na infância e vida adulta, sendo que a coriorretinite é a lesão mais freqüente. Entre as estratégias de prevenção da toxoplasmose congênita incluem-se a educação em saúde e a triagem pré-natal, com o objetivo de reduzir a exposição aos fatores de risco para a infecção por Toxoplasma gondii, detectar e tratar a infecção aguda na gestante. Os objetivos foram avaliar a prevalência e o risco de transmissão congênita por T. gondii, através da análise do perfil sorológico das mesmas e do conhecimento sobre as formas de transmissão da zoonose, verificar possíveis associações entre soropositividade das gestantes e a exposição aos fatores de risco da infecção, além de comparar as técnicas de Quimioluminescência e Imunofluorescência Indireta para o diagnóstico sorológico da toxoplasmose na amostra estudada. Foi realizado um estudo transversal, com 425 gestantes que realizaram o pré-natal nos Postos de Saúde de Pelotas-RS, no período de maio a novembro de 2006. Constatou-se uma soroprevalência (IgG) de 54,8% para T. gondii e não foi detectado a presença de anticorpos IgM. Na análise dos fatores de risco foi verificada associação significativa (p<0,05) entre a soropositividade das gestantes e a idade, manuseio de carne crua, consumo de vegetais crus, de carnes cruas ou mal cozidas, de leite cru não pasteurizado e contato direto com o solo. Através do modelo de regressão logística, essa associação foi confirmada para o consumo de carnes cruas ou mal cozidas (OR=1,85) e o contato direto com o solo (OR=2,67). O convívio com gatos, não apresentou associação significativa com a soropositividade para T. gondii nas pacientes estudadas. Constatou-se elevado desconhecimento da doença e das principais fontes da infecção pelas gestantes entrevistadas. A técnica de Quimioluminescência mostrou-se adequada ao diagnóstico de rotina da infecção por T. gondii, pois, além da praticidade, apresentou de sensibilidade, especificidade e acurácia comparáveis aos da Imunofluorescência Indireta. Os resultados obtidos indicam a necessidade da implantação de programas de prevenção primária da infecção por T. gondii para gestantes, a fim de reduzir o risco da toxoplasmose congênita.

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.

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.

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.

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.

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.

Resumen: En esta tesis doctoral se presentan tres modelos matemáticos que describen el comportamiento de dos enfermedades parasitarias con vector de transmisión; de los cuales dos modelos están dedicados a la Toxoplasmosis donde se explora la dinámica de la enfermedad a nivel de la población humana y de gatos domésticos. Los gatos juegan un papel de agentes infecciosos del Toxoplasma gondii. La dinámica cualitativa del modelo es determinada por el umbral básico de reproducción, R0. Si el parámetro R0 < 1, entonces la solución converge al punto de equilibrio libre de la enfermedad. Por otro lado, si R0 > 1, la convergencia es al punto de equilibrio endémico. Las simulaciones numéricas ilustran diferentes dinámicas en función del parámetro umbral R0 y muestra la importancia de este parámetro en el sector salud. Finalmente la Babesiosis bovina se modela a partir de cinco ecuaciones diferenciales ordinarias, que permiten explicar la influencia de los parámetros epidemiológicos en la evolución de la enfermedad. Los estados estacionarios del sistema y el número básico de reproducción R0 son determinados. La existencia del punto endémico y libre de enfermedad se expone, puntos que dependen del R0, ratificando la importancia del parámetro umbral en la salud publica. Objetivo: Construir modelos matemáticos epidemiológicos aplicados a enfermedades parasitarias (Toxoplasmosis y Babesiosis) con vector de transmisión. Metodología: Para la construcción de los modelos matemáticos epidemiológicos es necesario representar la enfermedad a partir de modelos de flujo, permitiendo ver la dinámica de la población entre los diferentes estadíos de la enfermedad, dichos movimientos son analizados a partir de sistemas dinámicos, análisis matemático y métodos numéricos; con estas herramientas es posible hacer un estudio detallado del modelo, permitiendo calcular parámetros umbrales que dominan la dinámica de la enfermedad y a su vez simular escenarios reales e hipotéticos. / Aranda Lozano, DF. (2011). Modeling of parasitic diseases with vector of transmission: toxoplasmosis and babesiosis bovine [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/11539 / Palancia

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