Made available in DSpace on 2014-12-17T14:13:56Z (GMT). No. of bitstreams: 1 CarlosAAG.pdf: 323369 bytes, checksum: 093c86d6d5662ee9fb5d64b4afd66037 (MD5) Previous issue date: 2004-02-19 / The objective of this study is to estimate the prevalence of Ocular Toxocariasis, Diffuse Unilateral Subacute Neuroretinitis (DUSN), Toxoplasma gondii infection and Ocular Toxoplasmosis in a student population in Natal-RN/Brazil and relate it to demographic, epidemiologic and socio-economic risk factors. The incidence of DUSN was observed in patients at the Federal University of Rio Grande do Norte Ophthalmology Service and the Prontoclinica de Olhos Ophthalmology clinic in Natal. In cases where a worm was found in the subretinal space, the result of treatment with photocoagulation using Green Laser (Eye Light ALCON) was evaluated in relation to final visual result. The sample was randomly selected among the schools of the four districts of Natal, according to the type of institution (public or private), its level (elementary or secondary), and study period (morning, afternoon or evening). The school population was studied from March to May, 2001. Initially, the students answered a questionnaire to evaluate demographic, epidemiologic and socio-economic risk factors. Afterwards, the following procedures were carried out: blood samples were taken for Toxoplasmosis (IgG, IgM) serology, hemogram, ophthalmological examination, consisting of clinical history, measurement of visual acuity, refraction under cycloplegia, biomicroscopy of the anterior segment and annexa, funduscopy and examination of extrinsic motility. The prevalence of Toxocariasis was 0.2% or 2 per one thousand students. The sample was insufficient to estimate the prevalence of DUSN. Seventy patients with DUSN diagnosis were examined from January, 2001 to January, 2003. A live worm was found in the subretinal space of all four patients in the acute phase, and these were treated with laser photocoagulation. After follow-up (average = 11.5 months), visual acuity improved in three eyes and remained unaltered in one eye. Worms were found in 22 of the 66 patients in the chronic phase, and these also were treated with laser photocoagulation. After a follow-up period of 13.1 months, on average, visual acuity improved in two of the patients, remained unchanged in 19 and worsened in one. The comparison of visual result before and after treatment was not statistically significant (p = 0.302). The diagnosis of DUSN in the acute phase, followed by prompt localization and destruction of the worm by photocoagulation, can improve the patient s vision. However, destruction of the worm by laser photocoagulation in eyes with DUSN in the chronic phase does not improve visual acuity. Seroprevalence for IgG was 46% (Confidence Interval CI 95%-42.9-49.2%) and for IgM it was 1.4% (CI 95% = 0.8-2.4%). The prevalence of ocular lesion was 1.15% (CI 95% = 0.6 - 2.0%). Socio-economic conditions were determinants in the prevalence of Systemic and Ocular Toxoplasmosis in the bivaried analysis and confirmed in the multivaried analysis (mother s scholarity illiterate/ OR = 2.9 and p < 0.001). The T. gondii infection prevalence, although high, was less than that found in studies performed in the South and Southeast of Brazil and that of Ocular Toxoplasmosis was completely discrepant, varying from 5 to 17 times less. Although important epidemiological variables such as owning a cat, drinking unfiltered water, and coming into contact with rivers or lakes showed an association in the preliminary analysis, they lost their influence when included in the logistic model. Future studies are scheduled to begin in March, 2004, in collaboration with other Brazilian and American universities in an attempt to discover the reason for these findings, as well as identifying the different strains of Toxoplasma gondii, and studying the sources of water utilized by the population of Natal Brazil / Esta pesquisa teve como objetivo, estimar a preval?ncia da Toxocar?ase Ocular, Neuroretininte Sub-aguda Difusa Unilateral (DUSN), Infec??o pelo Toxoplasma gondii e Toxoplasmose Ocular na popula??o de escolares de Natal-RN/Brasil e relacion?-la aos fatores de risco demogr?ficos, epidemiol?gicos e socioecon?micos. Estudar a incid?ncia de DUSN em pacientes atendidos no Servi?o de Oftalmologia da Universidade Federal do Rio Grande do Norte e Prontoclinica de Olhos, em Natal, bem como, avaliar, nos casos em que foi encontrada larva no espa?o sub-retiniano, o resultado do tratamento com fotocoagula??o utilizando o Laser Verde (Eye Light ALCON) em rela??o ao resultado visual. A amostra foi selecionada aleatoriamente e distribu?da nas escolas dos quatro distritos da cidade de Natal de acordo com a natureza da institui??o (p?blica ou privada), seu n?vel (fundamental ou m?dio) e turno em que o escolar estudava (matutino, vespertino ou noturno). A popula??o de escolares foi estudada no per?odo de mar?o a maio de 2001. Inicialmente, responderam a um question?rio para avalia??o de fatores de risco demogr?fico, epidemiol?gico e socioecon?mico. Depois foram feitos os seguintes procedimentos: coleta de sangue para realiza??o de sorologia para Toxoplasmose (IgG, IgM), hemograma, exame oftalmol?gico constando de hist?ria cl?nica, medida da acuidade visual, refra??o sob cicloplegia, biomicroscopia do segmento anterior e anexos, fundoscopia e exame da motilidade extr?nseca. A preval?ncia de Toxocar?ase foi de 0,2% ou 2 por mil escolares. A amostra n?o foi suficiente para estimar a preval?ncia de DUSN. Foram examinados 70 pacientes com diagn?stico de DUSN, no per?odo de janeiro de 2001 a janeiro de 2003. Foi encontrada larva viva no espa?o sub-retiniano de todos os quatro que se encontravam na fase aguda, e tratados com fotocoagula??o a laser. Ap?s acompanhamento dos pacientes (m?dia = 11,5 meses), a acuidade visual melhorou em tr?s olhos e permaneceu inalterada em um olho. Dos 66 pacientes na fase cr?nica, foi encontrada larva em 22 deles e tratados com fotocoagula??o a laser. Ap?s acompanhamento por um per?odo de 13,1 meses em m?dia, a acuidade visual melhorou em dois, permaneceu a inicial em 19 e diminuiu em um paciente. A compara??o do resultado visual antes e ap?s o tratamento, n?o foi estatisticamente significante (p = 0,302). O diagn?stico de DUSN na fase aguda, seguida por pronta localiza??o e destrui??o da larva por fotocoagula??o, pode melhorar a vis?o dos pacientes. No entanto, a destrui??o da larva por fotocoagula??o a laser em olhos com DUSN, na fase cr?nica, n?o melhora a acuidade visual. A soropreval?ncia para IgG foi de 46% (Intervalo de Confian?a -IC 95% - 42,9-49,2%) e para IgM foi 1,4% (IC 95% = 0,8-2,4%). A preval?ncia de les?o ocular foi 1,15% (IC 95% = 0,6 2,0%). As condi??es socioecon?micas foram determinantes na preval?ncia da Infec??o pelo T. gondii e Toxoplasmose Ocular na an?lise bivariada e confirmada na an?lise multivariada (escolaridade da m?e n?o alfabetizada/OR = 2,9 e p< 0,001). A preval?ncia de Toxoplasmose Sist?mica, embora elevada, foi menor do que a encontrada em estudos realizados no Sul e Sudeste do Brasil e, a da Toxoplasmose Ocular foi totalmente discrepante, variando de 5 a 17 vezes menos. Embora importantes vari?veis epidemiol?gicas, tais como possuir gato, beber ?gua n?o filtrada, ter contato com lagoas ou rios, tenham mostrado associa??o na an?lise preliminar, perderam sua influ?ncia quando inclu?das no modelo log?stico. Estudos futuros j? est?o planejados para ter inicio em mar?o pr?ximo, em colabora??o com outras Universidades do Brasil e dos Estados Unidos com a finalidade de encontrar a raz?o destes achados, bem como, identificar diferentes tipos de cepas do Toxoplasma gondii, e estudar as fontes de ?gua utilizadas pela popula??o de Natal-RN