Made available in DSpace on 2014-07-29T15:04:46Z (GMT). No. of bitstreams: 1 Ana Lucia Sartori.pdf: 902387 bytes, checksum: 8f24d598036950ca797090a56e953cb1 (MD5) Previous issue date: 2009-12-11 / The acute toxoplasmosis during pregnancy is an infection that can be transmitted to the fetus, causing a disease that varies in severity depending on the time of pregnancy when fetal infection occurred. Can be severe and cause miscarriage or major sequelae (neuro-optical) in survivors. The detection of women's vulnerability to infection and early diagnosis of acute infection in pregnant women provide for the use of prophylactic measures to prevent maternal infection and/or introducing therapeutic measures that can reduce the severity of fetal disease. Although toxoplasmosis screening is not mandatory in Brazil, in the State of Goiás, through the Pregnancy Protection Program, several infections are identified during prenatal care such as toxoplasmosis. This study aimed at estimating the prevalence of anti-Toxoplasma gondii antibodies and analyzing factors associated to seropositivity in pregnant women assisted by the Pregnancy Protection Program. This is a cross-sectional study from the Pregnancy Protection Program database records which considered the serologic trials outcomes carried out in filter paper samples for the IgG and IgM markers in pregnant women living in Goiânia screened in 2008. In order to amplify and improve the quality of data analysis, was carried out a deterministic linkage technique with Live Birth Information System database, thus linked to 10,316 records out of 12,843 records which were analyzed (80.3%). The infection prevalence was of 68.3% (CI 95%: 67.5-69.1), 0.74% (95/12,846) of which presented IgG and IgM reagents. The serum IgM and IgG avidity confirmation test was carried out in 93.7% (89/95) pregnant women suggestive of acute infection. The gestational week of the new collection was identified in 82 of them, and 52.5% (43/82) of which were on the 16th week of gestation or more weeks, it is not possible to determine if the infection occurred during pregnancy, and among these ones, the IgG avidity test value was higher than 60% in 35/43 pregnant women. The statistically associated variables (p<0,05) seropositivity were age group equal or higher than 20 years, black and mixed-race, school completion rate lower than 12 years and multiple pregnancies. The outcomes show a high prevalence of infection among pregnant women living in Goiânia and high patient compliance with the Program to perform the confirmatory test, however, the Pregnancy Protection Program s database presented a high percentage of records with variable not satisfied, justifying the adoption of strategies aimed at health professionals about the importance of filling the pregnancy's card and the information to the surveillance systems of State. / A toxoplasmose aguda na gestação é uma infecção que pode ser transmitida ao concepto, causando uma doença que varia em gravidade, dependendo da época da gestação em que aconteceu a infecção fetal. Pode ser grave e causar o abortamento ou importantes sequelas (neuro-ópticas) nos sobreviventes. A detecção da vulnerabilidade das mulheres a essa infecção e o pronto diagnóstico da infecção aguda na grávida proporcionam a utilização de medidas profiláticas para se prevenir a infecção materna e/ou se introduzir medidas terapêuticas que podem reduzir a gravidade da doença fetal. Embora o screening para toxoplasmose não seja obrigatório no país, no Estado de Goiás, por meio do Programa de Proteção à Gestante diversas infecções são identificadas durante a assistência pré-natal, entre elas a toxoplasmose. O objetivo deste estudo é estimar a prevalência de anticorpos e analisar fatores associados à soropositividade ao Toxoplasma gondii em gestantes atendidas no Programa de Proteção à Gestante. Trata-se de um estudo de corte transversal com uso de dados secundários do Programa de Proteção à Gestante que considerou os resultados dos testes sorológicos realizados em amostras de papel filtro para os marcadores IgG e IgM em gestantes atendidas durante 2008 e residentes em Goiânia. Para ampliar e melhorar a qualidade da análise dos dados foi realizada a técnica de linkage determinística com o banco de dados do Sistema de Informações sobre Nascidos Vivos, sendo vinculados 10.316 registros do total de 12.846 registros analisados (80,3%). A prevalência da infecção pelo Toxoplasma gondii foi de 68,3% (IC 95%: 67,5-69,1), sendo que destas, 0,74% (95/12.846) apresentaram IgG e IgM reagentes. O teste confirmatório da presença da IgM, acrescido do teste de avidez de anticorpos IgG em sangue venoso foram realizados em 93,7% (89/95) das gestantes suspeitas de infecção aguda. A semana gestacional da nova coleta foi identificada em 82 delas, sendo que 52,5% (43/82) estavam com mais de 16 semanas de gestação, não sendo possível determinar se a infecção ocorreu durante a gestação, apesar de 35/43 estarem com alta avidez (maior de 60%). As variáveis associadas estatisticamente (p<0,05) à soropositividade foram faixa etária igual ou superior a 20 anos de idade, cor/raça preta e parda, tempo de estudo inferior a 12 anos e ser multigesta. O estudo estimou uma alta prevalência da infecção entre gestantes residentes em Goiânia, e elevada adesão das pacientes ao Programa para realização do teste confirmatório, entretanto, a base de dados do Programa de Proteção à Gestante apresentou elevado percentual de registros com variáveis não preenchidas, justificando a adoção de estratégias voltadas aos profissionais de saúde acerca da importância do preenchimento do cartão da gestante, bem como dessas informações para os serviços de epidemiologia do Estado.

Submitted by Cláudia Bueno (claudiamoura18@gmail.com) on 2016-01-14T16:38:41Z No. of bitstreams: 2 Dissertação - Rebeka Cristine de Bastos Costa - 2015.pdf: 2127820 bytes, checksum: 8789b51096d386c4def09d0d1ee4da0d (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-01-15T09:55:51Z (GMT) No. of bitstreams: 2 Dissertação - Rebeka Cristine de Bastos Costa - 2015.pdf: 2127820 bytes, checksum: 8789b51096d386c4def09d0d1ee4da0d (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-01-15T09:55:51Z (GMT). No. of bitstreams: 2 Dissertação - Rebeka Cristine de Bastos Costa - 2015.pdf: 2127820 bytes, checksum: 8789b51096d386c4def09d0d1ee4da0d (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-08-25 / Toxoplasmosis is a zoonotic disease in which mammals and birds can join the cycle as intermediate hosts, and felids as definitive hosts. Felis catus is recognized as the main responsible for the environmental contamination by Toxoplasma gondii oocysts. Serological diagnosis reveals little about the elimination of oocysts of T. gondii into the environment, principally by F. catus, which plays an important role in Public Health. There are few data on the frequency of feline toxoplasmosis in the State of Goiás. Therefore, the aim of this research was to evaluate the frequency of toxoplasmosis infection in domestic cats and their potential role in its transmission through the oocyst elimination into the environment and the respective factors associated with the infection. For this, we collected 102 blood samples and 98 fecal samples from 102 cats from Goiânia, State of Goiás. The animals were divided into groups according to age, gender and free access to the street or not. Indirect hemagglutination test was performed to determine the level of anti-T. gondii and indirect ELISA for the detection of infection by feline immunodeficiency virus (FIV). For search and detection of T. gondii oocysts elimination in the feces of cats we performed a centrifugal-flotation with Sheather's solution, subsequently we extracted DNA and used conventional PCR. The results showed that 18.63% (19/102) of the cats were positive for T. gondii, with titers ranging from 1:32 to 1: 8.192, while none of the fecal samples were positive in the PCR. The frequency of positive animals for FIV was 55.91% (52/93), and 18.28% (17/93) presented coinfection. By multivariate logistic regression we found the associated factors were the same for both infections, but one did not interfere with another. The factors associated with infection by T. gondii and feline immunodeficiency virus were free life and age under six months, since the sex was not statistically related to any of the illnesses. / A toxoplasmose é uma zoonose na qual, mamíferos e aves podem participar do seu ciclo como hospedeiros intermediários e os felídeos como hospedeiros definitivos. O Felis catus é reconhecido como o principal responsável pela contaminação ambiental por oocistos de Toxoplasma gondii. O diagnóstico sorológico pouco revela sobre a eliminação de tal fase no ambiente, o que representa o real impacto daquela espécie na Saúde Pública frente à toxoplasmose. São escassos os dados da frequência da toxoplasmose felina no Estado de Goiás. Assim sendo, objetivou-se com esta pesquisa avaliar a frequência da infecção da toxoplasmose em gatos domésticos e o seu potencial papel na sua transmissão, através da eliminação de oocistos no ambiente e dos respectivos fatores associados à infecção. Para isto, foram coletadas 102 amostras de sangue e 98 amostras fecais, de 102 gatos provenientes de Goiânia-Goiás. Os animais foram divididos em grupos de acordo com a faixa etária, gênero e livre acesso à rua ou não. Foi realizada a hemaglutinção indireta para a determinação do nível de anticorpos anti-T. gondii e o ELISA indireto para a detecção da infecção pelo vírus da imunodeficiência felina (FIV). Para a pesquisa e detecção da eliminação de oocistos de T. gondii nas fezes dos gatos foi feita a centrifugo-flutuação em solução de Sheather, posterior extração de DNA e realização da PCR convencional. Os resultados revelaram que 18,63% (19/102) dos gatos foram positivos para o T. gondii, com títulos variando entre 1:32 a 1:8.192, sendo que nenhuma das amostras fecais foi positiva na PCR. A frequência de positivos para o FIV foi de 55,91% (52/93), com coinfecção de 18,28% (17/93). Com a regressão logística multivariada verificou-se que os fatores associados foram os mesmos para as duas infecções, porém uma não interferiu diretamente na outra. Os fatores associados para a infecção pelo T. gondii e pelo vírus da imunodeficiência felina foram a vida livre e a idade igual ou superior a seis meses, já o gênero não apresentou relação estatística com nenhuma das enfermidades.

Submitted by Erika Demachki (erikademachki@gmail.com) on 2015-03-24T17:25:34Z No. of bitstreams: 2 Tese - Joseneide Teixeira Câmara - 2014.pdf: 2654661 bytes, checksum: 45d6b37146cb1b9be595aa54c97b9a6a (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Erika Demachki (erikademachki@gmail.com) on 2015-03-24T17:27:34Z (GMT) No. of bitstreams: 2 Tese - Joseneide Teixeira Câmara - 2014.pdf: 2654661 bytes, checksum: 45d6b37146cb1b9be595aa54c97b9a6a (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-03-24T17:27:34Z (GMT). No. of bitstreams: 2 Tese - Joseneide Teixeira Câmara - 2014.pdf: 2654661 bytes, checksum: 45d6b37146cb1b9be595aa54c97b9a6a (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-05-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The vertical transmission of infection from mother to child, and may increase morbidity and mortality of both mother and child, when not diagnosed and by suitably dealest, causing a serious public health problem. This study aimed to estimate the prevalence of antibodies to toxoplasmosis, rubella, cytomegalovirus, hepatitis B, syphilis and HIV among pregnant women in Caxias, Maranhão, Brazil and identify the main factors associated with seropositivity for Toxoplasma gondii infection in pregnant women attending two referral centers Caxias, MA. Descriptive, observational, cross-sectional study of 561 pregnant women who received prenatal care at two clinics reference to prenatal high risk in the period July 2011 to December 2012, the outpatient clinics of Maternity Carmosina Coutinho (MCC) and the Specialized Center for Maternal and Child Care (CEAMI). Serological tests for toxoplasmosis, rubella, cytomegalovirus, hepatitis B were performed by a laboratory conveniado to the municipality by the same trained technician, and for syphilis and HIV were performed in the Counseling and Testing Center (ATC) in the city laboratory. And a small sample of whole blood from five pregnant IGM reagent for Toxoplasma gondii and their respective newborns was processed at the Institute of Tropical Pathology and Public Health in the Department of Parasitology UFG for performing Polymerase Chain Reaction (PCR). Statistical analysis was performed using SPSS version 20.0 Windows, using the chi-square tests of association and Odds Ratio (95%CI), considering a significance level of 5%. It was found to be positive for HIV was 0.4%, 2.0% syphilis, rubella and cytomegalovirus IgG reactivity were 93.6% and 87.8% respectively without reactive IgM, HBsAg was negative for all pregnant women in the sample tested. Regarding toxoplasmosis in 437 (77%), 124 susceptibility (22.1%) and 5 (0.9%) women with active infection. Found no significant association between toxoplasmosis susceptibility and age, location, income, education, sewerage, number of pregnancies and gestational age. Variables with significant association (p≤0.05) were seropositive pregnant women who are multiparous (p=0.036), living with dogs stuck at home (p=0.001), and consumption of raw kibbeh (p=0.036). The frequency of seropositivity of these infectious diseases of vertical transmission in pregnant women seen at antenatal care in the city of Caxias-MA is considered high, but are similar to those described in other regions of Brazil. Pregnant women who are multiparous who perform consumption of raw kibbeh and live with dogs that do not wobble on the street, had more chance of becoming infected with Toxoplasma gondii, thus guidance on primary prevention measures and quarterly serological monitoring should be strengthened these infections of pregnant women, since it is important to identify and/or prevent congenital infection measured. / A transmissão vertical das infecções da mãe para o filho e pode aumentar a morbimortalidade do binômio mãe-filho. Quando não diagnosticadas e tratadas adequamente, e ocasionam um sério problema de saúde pública. Este estudo objetivou estimar a soroprevalência de anticorpos para toxoplasmose, rubéola, citomegalovírus, hepatite B, sífilis e HIV entre gestantes em Caxias, Maranhão, Brasil e identificar os principais fatores associados à soropositividade para o Toxoplasma gondii (T. gondii) em gestantes atendidas em dois centros de referência em Caxias–MA. Estudo descritivo, observacional, transversal, com 561 gestantes que realizaram a assistência pré-natal em dois ambulatórios de referência para pré-natal de alto risco, no período de julho de 2011 a dezembro de 2012, nos ambulatórios da Maternidade Carmosina Coutinho (MCC) e no Centro Especializado de Assistência Materno-Infantil (CEAMI). Os testes sorológicos de toxoplasmose, rubéola, citomegalovírus, hepatite B foram realizados por um laboratório conveniado ao município, e para sífilis e HIV foram realizadas no laboratório do Centro de Testagem e Aconselhamento (CTA) do município. Uma amostra de sangue total das cinco gestantes IGM reagente para o T. gondii e de seus respectivos recém-nascidos foi processada no Instituto de Patologia Tropical e Saúde Publica da UFG no Setor de Parasitologia para a realização de Reação em Cadeia da Polimerase (PCR). A análise estatística foi realizada com o programa SPSS versão 20.0 Windows, usando os testes de associação qui-quadrado e Odds Ratio (IC95%), considerando-se o nível de significância de 5%. Constatou-se que a soropositividade para HIV foi de 0,4%, sífilis 2,0%, rubéola e citomegalovírus a reatividade de IgG foram de 93,6% e 87,8% respectivamente sem IgM reativa, HBsAg foi não reagente para todas as gestantes da amostra. Em relação ao T. gondii 437 (77,9%) foram soropositivas, a susceptibilidade em 124 (22,1%) e 5 (0,9%) gestantes com infecção ativa. Não foi observada associação significativa entre soropositividade para toxoplasmose e idade, procedência, renda, escolaridade, rede de esgotos, número de gestações e idade gestacional. As variáveis com associação significativa (p≤0,05) para soropositividade foram gestantes que são multigestas (p=0,036), convívio com cães presos em casa (p=0,001), e consumo de quibe cru (p=0,036). A frequência de soropositividade dessas doenças infecciosas de transmissão vertical em gestantes atendidas no pré-natal, no município de Caxias-MA é considerada alta, mas encontram-se semelhantes aos descritos em outras regiões do Brasil. As gestantes que são multigestas que realizam consumo de quibe cru e convivem com cães presos em casa, apresentaram mais chance de se infectar com o Toxoplasma gondii, assim, deve ser reforçada orientações sobre medidas de prevenção primária e o monitoramento sorológico trimestral dessas infecções às gestantes, uma vez que são medidas importantes para identificar e/ou prevenir as infecções congênitas.

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.

Toxoplasma gondii est le parasite responsable de la toxoplasmose, une zoonose infectant l'Homme et les autres espèces endothermes. Les fermes d'élevage sont connues pour présenter de forts risques de transmission pour les hôtes et constituent des réservoirs de la contamination environnementale en milieu rural. Cette étude visait à identifier les facteurs modulant la circulation du parasite dans les fermes dans deux compartiments du cycle: les hôtes définitifs et le sol. Pour cela, la dynamique d'infection par T. gondii dans cinq populations de chats a été suivie et modélisée par des modèles de capture-marquage-recapture « multi-événements ». Ceux-ci ont montré que les taux d'expositions des chats à T. gondii varient entre fermes et que les taux d'infection sont plus élevés en automne-hiver que durant le reste de l'année. La distribution spatiale de la contamination environnementale par T. gondii a ensuite été évaluée dans six fermes par recherche d'ADN dans des prélèvements de sols, puis mise en relation avec le patron de dépôt des fèces par les chats. Malgré une large distribution de T. gondii dans les fermes, les sites de défécation des chats constituent des zones à fort risque de transmission. Le niveau de contamination dans ces sites est dépendant de leur localisation et des caractéristiques des chats qui les utilisent, tout deux influencés par la localisation du site d'alimentation des chats dans les fermes. Cette étude montre que les fermes peuvent présenter des disparités en termes d'exposition au parasite. A l'intérieur des fermes, le patron spatio-temporel de dépôt des fèces par les chats modulent les risques d'infection pour les hommes et les animaux. / Toxoplasma gondii is the protozoan parasite responsible for toxoplasmosis, a zoonosis infecting humans and other endothermic animals. Livestock farms are considered high-risk sites for T. gondii transmission to hosts and they represent reservoirs of environmental contamination in rural areas. The aim of this study was to investigate the infection dynamics of T. gondii in cat populations by surveying five dairy farms using multi-event capture–mark–recapture models. The results showed that the rates of T. gondii infection in cats varied between farms. Infection rates were higher in autumn and winter compared to the rest of the year. The spatial distribution of soil contaminated by T. gondii on six farms was assessed using quantitative PCR on soil samples and analyzed in relation to the spatio-temporal pattern of faeces deposition by cats. Although there was wide spatial distribution of T. gondii in the soil of the farms, cat defecation sites were revealed to be high-risk areas for T. gondii transmission. The level of contamination in these sites depended on their location and characteristics of cats that use them, which were both influenced by the location of the main cats feeding site in the farms. This study demonstrated that T. gondii exposure varies from one farm to another. Infection risk is also heterogeneous within a farm and is driven by the spatio-temporal pattern of deposition of cat faeces.

The subject of the dissertation deals with the secondary school pupil's awareness of zoonoses. Zoonoses are the diseases transmited from animals to human beings. Those are one of the topics of biology study currently. The main aim of the dissertation is theoretical definition of the matter in the first place. For knowledge testing have been chosen these four illness: Toxoplasmosis, Lyme boreliossis, Rabies and Creuzfeldt-Jakobo disease. With these chosen illness the main research goal is to provide a comprehensive collection of information about the details such as disease transfer, spread of the disease, disease development, cure and avoidance. The research part of the dissertation tries to find out the extent of knowledge about the chosen kinds of zoonoses among the pupils at specialized secondary schools. As a tool of quantitative research has been used a pupil's didactic test. As based on the evaluated results we may say that the pupil's knowledge at explored schools is relatively satisfactory.

Toxoplasma gondii est un parasite répandu, ayant un impact médical et vétérinaire. Chez les hôtes intermédiaires, les tachyzoïtes et les bradyzoïtes sont responsables de la toxoplasmose aiguë (TA) et chronique (TC), respectivement. Sous la réponse immunitaire, la TA évolue en TC, se manifestant par des kystes latents dans le cerveau et les muscles squelettiques. De plus, une forte corrélation existe entre la TC et plusieurs neuropathologies et cancers. Chez les patients immunodéprimés, la TC peut être réactivée et conduire à une maladie potentiellement fatale. Les traitements actuels ciblent principalement les TA, et présentent plusieurs effets secondaires. Nous nous sommes concentrés sur la TC et la compréhension de ses mécanismes moléculaires. Nous avons d’abord étudié l’efficacité de l’imiquimod contre la TA et la TC. Au cours de la TA, l'imiquimod a entraîné le recrutement de cellules T dans le péritoine et la rate de souris traitées et a considérablement diminué le nombre de kystes cérébraux lors de l'établissement de la TC. Remarquablement, le gavage de souris avec les kystes cérébraux restants chez des souris traitées à l'imiquimod n'a pas pu induire de TC. Après l'établissement de la TC, nous avons démontré que l'imiquimod réduisait considérablement le nombre de kystes cérébraux chez les souris chroniquement infectées et augmentait les récepteurs Toll-Like 11 et 12, qui se lient à une protéine du tachyzoïte, la profiline. Parallèlement, l’expression de TLR-7 augmentait, probablement par son agoniste, l'imiquimod. L'imiquimod induit une interconversion, comme l'indiquent la diminution du taux de protéine P21 et l'augmentation du taux de protéine P30, exprimées exclusivement et respectivement chez les bradyzoïtes et les tachyzoïtes. Les voies en aval de TLR-11/12 ont été activées via la voie MyD88 de signalisation, entraînant une induction ultérieure de la réponse immunitaire. In vitro, l'imiquimod n’affecte pas la souche Toxoplasma dépourvue de profiline, suggérant un rôle via le complexe Profilin/TLR-11/12. Enfin, le traitement par l'imiquimod a régulé positivement les transcrits des ligands 9 (CXCL9) et 10 (CXCL10), connus pour induire le recrutement de lymphocytes T dans des foyers réactivés du Toxoplasme afin d'éliminer l'infection.Ensuite, nous nous sommes concentrés sur les mécanismes moléculaires impliqués dans la TA et particulièrement dans la TC. Nous avons caractérisé P18, un membre de la superfamille SRS. Lorsque nous avons supprimé P18, la virulence était atténuée au cours de la TA, dû à un échappement plus rapide des tachyzoïtes du péritoine de souris, parallèle à un recrutement significatif de cellules dendritiques. De manière concomitante, moins de tachyzoïtes étaient détectés dans la rate, tandis que plus de parasites ont atteint le cerveau de souris infectées. L’élimination de P18 a augmenté le nombre de kystes de bradyzoïtes in vitro et dans le cerveau de souris infectées. Une expression induite de cytokines, notamment CXCL9 et 10, a également été observée. L’immunosuppression de souris KO P18 infectées a retardé la réactivation. L’infection orale de souris immunodéficientes ayant des macrophages fonctionnels a montré un prolongement de survie, contrairement aux souris n’ayant pas de macrophage, soulignant un rôle de l'IFN-g dans l’interconversion. Collectivement, ces données confirment le rôle de P18 dans la modulation de la réponse immunitaire, facilitant le passage des tachyzoïtes dans le cerveau et favorisant la formation de kystes. P18 joue également un rôle central dans la réactivation et la dissémination de parasites de manière dépendante de l'IFN-g. Dans l'ensemble, nous avons montré le potentiel thérapeutique prometteur de l'imiquimod contre la toxoplasmose et caractérisé le rôle de P18 dans l'immunomodulation afin de contrôler la dissémination et l'interconversion. Notre étude ouvre la voie à de nouvelles approches thérapeutiques contre la toxoplasmose, sa persistance et sa réactivation. / Toxoplasma gondii is a prevalent parasite of medical and veterinary impact. In intermediate hosts, tachyzoïtes and bradyzoïtes are responsible for acute and chronic toxoplasmosis (AT and CT), respectively. In immunocompetent patients, AT evolves, due to the host immunity, into a persistent CT, which manifests as latent tissue cysts in the brain and skeletal muscles. CT correlates with several neuro-pathologies and cancers. In immunocompromised patients, CT may reactivate and poses a life threatening condition. Current treatments primarily target AT, are limited to general anti-parasitic/anti-bacterial drugs, and associate with several limitations. Here, we focused on targeting CT and understanding its molecular mechanisms. First, we explored the efficacy of Imiquimod against AT and CT. During AT, Imiquimod led to recruitment of T cells to peritoneum and spleen of treated mice and significantly decreased the number of brain cysts upon establishment of CT. Remarkably, gavage of mice with the remaining brain cysts from Imiquimod treated mice, failed to induce CT. Post-establishment of CT, we demonstrated that Imiquimod sharply reduced the number of brain cysts in chronically infected mice, and significantly increased Toll-Like Receptors 11 and 12. These TLRs are usually expressed by dendritic cells and monocytes, and bind a tachyzoïte actin-binding protein, profilin. Concomitantly, TLR-7 was upregulated, likely by its agonist Imiquimod. Imiquimod induced interconversion as documented by the decreased protein levels of P21, and increased protein levels of P30, exclusively expressed in bradyzoïtes and tachyzoïtes respectively. Pathways downstream from TLR-11/12 were activated, through MyD88 dependent TLR signaling, which resulted in subsequent immune response induction. In vitro, Toxoplasma strain lacking profilin, does not respond to Imiquimod, suggesting a role through Profilin/TLR-11/12. Finally, Imiquimod treatment upregulated the transcript expression levels of Chemokine (C-X-C motif) ligand 9 (CXCL9) and 10 (CXCL10), known to induce T cell recruitment to reactivated Toxoplasma foci to clear the infection.Then, we focused on molecular mechanisms involved in AT and notably CT. We characterized P18, a Surface-Antigen 1 (SAG-1) Related Sequence (SRS) superfamily member. When we deleted P18, the virulence was attenuated during AT. Indeed, P18 depletion led to a faster clearance of the parasites from the peritoneum of mice, paralleled by a substantial recruitment of dendritic cells, presumably a vehicle for tachyzoïte dissemination. Concomitantly, a lower number of tachyzoïtes was detected in the spleens while a higher number of parasites reached the brains of infected mice. P18 depletion increased the number of bradyzoïte cysts, in vitro and in the brains of infected mice. An induced expression of cytokines/chemokines, including CXCL9 and 10 was also observed. Immunosuppression of infected mice with KO P18, delayed reactivation. Oral infection of Severe Combined Immunodeficiency (SCID) (with IFN-g secreting macrophages), and NOD/Shi-scid/IL-2Rgnull (NSG) mice (lacking IFN-g), showed a significant prolonged survival in infected SCID but not NSG mice. This underlines a role for IFN-g in the conversion from bradyzoïtes to tachyzoïtes. Collectively, these data support a role of P18 in orchestrating the immune response, which ultimately facilitates tachyzoïte trafficking to the brain and favors cyst formation. P18 plays also a central role in parasite reactivation and dissemination in an IFN-g dependent fashion.Altogether, we showed the promising therapeutic potential of Imiquimod against toxoplasmosis and characterized P18 role in immunomodulation to control dissemination and interconversion. Our study paves the path towards new therapeutic approaches against toxoplasmosis. It tackled key questions pertaining to establishment, maintenance and reactivation of CT and should result in a comprehensive solution to this endemic disease.

Possible connection between latent toxoplasmosis and schizophrenia is a very interesting and medically important topic. In this thesis I tried to map current state of knowledge in the interdisciplinary research of schizophrenia and Toxoplasma gondii and their possible connections as well as to show differences in responses between Toxoplasma-positive and Toxoplasma-negative subjects using simple computer-administered tests of prepulse inhibition of startle reaction (PPI). Such differences would suggest another similarity between schizophrenia patients and subjects with latent toxoplasmosis as the sensorimotor gating responsible for PPI was found to be disrupted in schizophrenia patients. Side goal of the study was to test newly developed PC software for testing PPI and to determine its applicability in further research. Subjects for the tests were recruited among adepts of professional military service; 409 subjects completed the test of acoustic PPI and 276 subjects completed the test of visual PPI. All the subjects were tested on presence of specific anti-Toxoplasma IgG in their blood serum. Both tests revealed significant (p<0.001) differences between responses on prepulse-preceded stimuli and plain stimuli without prepulse, no significant results were, however, gained for the effects of latent...

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O genótipo e a carga parasitária constituem dois dos principais fatores associados à patogênese na toxoplasmose congênita. Na Europa e nos EUA, o genótipo II é o mais prevalente em infecções congênitas, enquanto que na América do Sul existem evidências apontando uma maior frequência de genótipos atípicos ou recombinantes, associados a casos mais graves. A carga parasitária também parece atuar como fator de risco independente associado ao prognóstico fetal. Os objetivos do estudo foram padronizar uma amplificação quantitativa (qPCR) com iniciadores do gene B1 para avaliar a carga parasitária; determinar o genótipo parasitário por multiplex-nested-PCR-RFLP dos marcadores 5\'-SAG2, 3\'-SAG2, SAG3 e GRA6, seguido de sequenciamento para confirmação da RFLP e análise de mutações; e verificar se existiria associação entre a carga parasitária e os genótipos parasitários nas mesmas gestações. Foram analisadas 76 amostras de líquido amniótico de gestações com toxoplasmose e 31 amostras controle. A qPCR apresentou LOD de 10 parasitos/mL, detectou as 76 amostras de estudo e nenhum controle. As cargas parasitárias variaram de 222 a 808.328 parasitos/mL. Houve duas amostras com valores acima de 104 parasitos/mL, apesar de todas as gestantes serem tratadas. Na genotipagem, SAG3 amplificou 55 amostras (54 tipo III e uma tipo II); 5\' e 3\'-SAG2 amplificaram 54 amostras (todas tipo I), e GRA6, amplificou 20 amostras (todas tipo III). A única amostra com genótipo parasitário SAG3-tipo II foi a que apresentou mais mutações (n=4), carga parasitária de 958 parasitos/mL, porém o recém-nascido foi assintomático. Houve diferença do número de amostras amplificadas por SAG3, e 5\' e 3\'-SAG2 em relação a GRA6 (McNemar, p<0,001). Os sequenciamentos confirmaram 100% dos resultados de RFLP, e foram encontradas 24 amostras com e 52 sem mutações, não existindo diferenças entre as cargas parasitárias dos dois grupos (Mann-Whitney, p= 0,085). Mais de uma mutação foi observada em cinco amostras. Foram detectadas 37 mutações no estudo: 26 heterozigotas/sinônimas e 11 homozigotas/sinônimas, não havendo regiões hot spot. Quanto à correlação clínico-laboratorial, dos 76 recém-nascidos, todos apresentaram IgM positiva ao nascimento, e 75 eram assintomáticos. O único recém-nascido sintomático apresentava tríade de Sabin e uma das duas cargas parasitárias mais elevadas do estudo (309.574 parasitos/mL), porém o genótipo não foi discriminante e não havia mutações. A outra amostra com carga parasitária acima de 104 parasitos/mL pertencia a recém-nascido assintomático, com genótipo não discriminante, e sem mutações. O estudo concluiu que a técnica de Real Time PCR (qPCR) foi padronizada com sucesso, usando os iniciadores B22 e B23 do gene B1 do parasito, podendo ser empregada na rotina diagnóstica. Além disso, foi possível realizar a genotipagem das amostras incluídas no estudo, com melhor desempenho de SAG3 e 5\' e 3\'-SAG2. O sequenciamento confirmou a confiabilidade da técnica de RFLP, e encontrou frequência elevada de mutações, todas sinônimas, sem regiões hot spot, e aparentemente sem associação com a carga parasitária. Houve elevada variabilidade das cargas parasitárias, porém grande homogeneidade dos genótipos parasitários, não tendo sido observada associação entre a carga parasitária e os genótipos de T. gondii no estudo. / The genotype and the parasite load are two of the main factors associated with pathogenesis in congenital toxoplasmosis. In Europe and the USA, genotype II is the most prevalent in congenital infections, while in South America there is evidence pointing to a higher frequency of atypical or recombinant genotypes associated with more severe cases. The parasite load also appears to act as an independent risk factor associated with fetal prognosis. The study objectives were to standardize a quantitative amplification (qPCR) with B1 gene primers to assess the parasite load; determine the genotype by multiplex-nested-PCR-RFLP of 5\' and 3\'-SAG2, SAG3 and GRA6 markers, followed by sequencing to confirm RFLP and analyze mutations, verifying whether there is association between parasite load and parasite genotypes in the same pregnancies. We analyzed 76 amniotic fluid samples from pregnancies with toxoplasmosis and 31 controls. The qPCR presented LOD of 10 parasites/mL, detected the 76 study samples and no control. Parasite loads ranged from 222 to 808,328 parasites/mL. There were two samples with values above 104 parasites/mL, despite all pregnant women be treated. In genotyping, SAG3 amplified 55 samples (54 type III and 1 type II); 5 \'and 3\'-SAG2 amplified 54 samples (all type I); and GRA6, amplified 20 samples (all type III). The only sample with genotype SAG3-type II showed the highest number of mutations (n=4), parasite load of 958 parasites/mL, but the newborn was asymptomatic. There were differences in the number of samples amplified by SAG3, and 5 \'and 3\'-SAG2 over GRA6 (McNemar test, p <0.001). Sequencing confirmed 100% of the RFLP results; and found 24 samples with and 52 without mutations, with no difference between the parasite load of these two groups (Mann-Whitney, p= 0.085). More than one mutation was observed in five samples. A total of 37 mutations were detected in this study: 26 heterozygotes/synonymous and 11 homozygous/synonyms, with no hot spot regions. Regarding the clinical-laboratory correlation, among the 76 newborns, all showed positive IgM at birth, and 75 were asymptomatic. The only symptomatic newborn presented the Sabin\'s triad and one of the two higher parasite loads in the study (309,574 parasites/mL). However, the genotype was not discriminant and no mutations were detected. The other sample with parasite load above 104 parasites/mL belonged to an asymptomatic newborn with a non-discriminating genotype, and no mutations. The study concluded that the Real Time PCR (qPCR) was successfully developed with primers B22 and B23 of the parasite B1 gene, and can be used in routine practice. Moreover, it was possible to perform the samples genotyping, with better performance of SAG3 and 5 \'and 3\'-SAG2. Sequencing results confirmed the RFLP reliability, and found a high frequency of mutations, all synonymous, with no hot spot regions, and apparently not associated with the parasite load. There was a high variability in parasite load, however great homogeneity of parasite genotypes, with no association between the parasite load and T. gondii genotypes in the study.