Submitted by Rosivalda Pereira (mrs.pereira@ufma.br) on 2017-09-14T20:45:25Z No. of bitstreams: 1 HerminioMendes.pdf: 6465933 bytes, checksum: b67849d7574d0171fe7eab9850a0985a (MD5) / Made available in DSpace on 2017-09-14T20:45:25Z (GMT). No. of bitstreams: 1 HerminioMendes.pdf: 6465933 bytes, checksum: b67849d7574d0171fe7eab9850a0985a (MD5) Previous issue date: 2017-06-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Fundação de Amparo à Pesquisa e ao Desenvolvimento Científico e Tecnológico do Maranhão / The use of food for probiotic bacteria has recently been considered a possibility of prevention against the installation or attenuation of several infectious processes. Species belonging to the genera Bifidobacterium and Lactobacillus predominate in the gastrointestinal microbiota and are widely used in functional foods. In general, a selection of new probiotic strains for use in humans has as its source a human intestinal flora and breast milk. Thus, the objective of this study was to isolate and identify new species with potential probiotic from samples of breast milk and feces of infants exclusively breastfed, in addition to evaluating their probiotic potential. Samples of breast milk from two different lactation periods (colostrum and transitional milk) and samples of fecal material from infants were used. Isolation was used using MRSC and for Beerens for Lactic-Acid Bacteria and Bifidobacterium spp. respectively. Probiotic potential was assessed by physical pH and bile salt tolerance tests. Verified its ability to adhere to mucin and human intestinal cells (HT-29) and inhibit adhesion of different diarrheogenic strains of E. coli. The identification of the promising isolates was performed through the 16S rDNA region. Five isolates had acid-bile resistance, with CLM0109 insulation having 90.2% and 64.6% resistance, pH 3.0 and pH 2.0, respectively. These isolates have an ability to adhere to mucin and HT-29 cells, the isolate FEB0308 showed the highest level of adherence to HT-29 cells. The adhesion assay demonstrated that all isolates were absorbed by adhesion of diarrheogenic E. coli (DECs). Antimicrobial susceptibility analysis showed that 3 isolates showed resistance to one or two antibiotics (kanamycin and streptomycin). The molecular analysis allowed identifying the isolates as belonging to the species Lactobacillus casei. The results show that the five isolates present probiotic potential especially for use in the prevention and treatment of infections caused by DEC and demonstrate that milk and stool samples from infants can act as a source of potential probiotic bacteria. / O uso de alimentos contendo bactérias probióticas foi recentemente considerado uma possibilidade de prevenção contra a instalação ou atenuação de diversos processos infecciosos. Espécies pertencentes aos gêneros Bifidobacterium e Lactobacillus predominam na microbiota gastrintestinal humana e são amplamente utilizadas em alimentos funcionais. Em geral, a seleção de novas cepas probióticas para uso em humanos, tem como fonte a microbiota intestinal humana e o leite materno. Dessa forma, o objetivo deste estudo foi isolar e identificar novas estirpes com potencial probiótico a partir de fezes de lactentes amamentados exclusivamente com leite materno, além de avaliar seu potencial probiótico. Foram utilizadas amostras de material fecal de bebes alimentados exclusivamente com leite materno. O isolamento foi realizado utilizando-se ágar MRSC e ágar Beerens para bactérias ácido-lácticas (BAL) e Bifidobacterium spp. respectivamente. O potencial probiótico foi avaliado pelos testes de tolerância ao pH gástrico e sais biliares. Além disso, foi verificado sua capacidade de aderir à mucina e as células intestinais humanas (HT-29), bem como a capacidade de inibir adesão de distintas linhagens diarreiogênicas de E. coli além de sensibilidade a antimicrobianos. A identificação dos isolados promissores foi realizada através da região 16S rDNA. Cinco isolados apresentaram resistência ácido-biliar, com destaque para o isolado CLM0109 que apresentou 90.2% e 64.6% de resistência a pH 3.0 e pH 2.0 respectivamente. Estes isolados tiveram a capacidade de aderir à mucina e células HT-29, o isolado FEB0308 apresentou o maior nível de aderência a células HT-29. O ensaio de inibição da adesão demonstrou que todos os isolados foram capazes de inibir adesão de E. coli diarreiogênicas (DECs). Além disso, a análise de sensibilidade a antimicrobianos demonstrou que 3 isolados apresentaram resistência a um ou dois antibióticos (canamicina e estreptomicina). A análise molecular identificou os isolados como Lactobacillus casei. Concluímos que os cinco isolados apresentam potencial probiótico especialmente para uso na prevenção e tratamento de infecções causadas por DEC e demonstra que as amostras fecais de lactentes alimentados exclusivamente com leite materno, podem funcionar como fonte de bactérias com potencial probiótico.

Les maladies diarrhéiques demeurent une cause majeure de mortalité infantile dans les pays en développement (PED). Du fait de l'insuffisance des plateaux techniques, les diagnostics étiologiques sont rarement réalisés et les traitements sont alors probabilistes. A Madagascar les données sur les diarrhées sont souvent parcellaires et anciennes. Le Réseau de surveillance sentinelle développé par l'Institut Pasteur de Madagascar à partir de 2007 nous a permis d'étudier la distribution spatio-temporelle des consultations pour diarrhée. Mais cette surveillance syndromique n'est pas couplée systématiquement à une surveillance biologique. Pour étudier les agents étiologiques des diarrhées, nous avons réalisé une enquête cas-témoins menée en 2008-2009 en milieu communautaire, chez les enfants de moins de 5 ans dans 14 districts. Nous avons pu identifier au moins un pathogène chez plus de la moitié des enfants (55%), avec une prédominance des étiologies parasitaires (37,2% des diarrhées), suivies par les bactéries (15%) puis les virus (6,7% de rotavirus). Les parasites ont été les seules étiologies pour lesquelles une pathogénicité a pu être mise en évidence. Parmi les étiologies bactériennes, l'infection à Campylobacter a été la plus fréquente (9,5%). Pour analyser le rôle de Campylobacter et les effets des facteurs environnementaux dans la survenue des diarrhées infantiles, nous avons initié et coordonné depuis 2010 une étude de cohorte dynamique d'enfants inclus avant l'âge de 24 mois et suivis jusqu'à l'âge de 36 mois à Moramanga, site où la prévalence de Campylobacter a été la plus élevée au cours de l'étude de 2008 (20,6%). Une surveillance des diarrhées a été menée 2 fois par semaine et les portages asymptomatiques évalués à l'inclusion et tous les 2 mois. Une étude de portage familial a été mise en œuvre ainsi qu'un suivi coprologique bi-annuel de la population avicole, des points d'eaux collectifs et de l'eau de boisson des familles. La recherche de Campylobacter chez les volailles portait sur les écouvillonnages rectaux. De janvier 2010 à mai 2012, 508 enfants correspondant à 256 346 enfant-jour ont participé à l'étude. La prévalence globale d'isolement de Campylobacter a été de 9,3%. Plus de 2/5 des enfants (43,3%) ont eu au moins un épisode d'infection à Campylobacter au cours de leur suivi. Les taux d'incidence annuelle des diarrhées ainsi que des infections symptomatiques ont été faibles, respectivement de 0,7 épisode /enfant et de 5,8 épisodes/100 enfant pouvant s'expliquer par le faible niveau d'exposition environnementale des enfants. Nous avons pu étudier l'importance des facteurs liés à l'hôte comme l'âge. Le pic d'infection à Campylobacter se situe entre 18 à 29 mois, celui des diarrhées entre 6 à 11 mois puis diminue ensuite. La 1ère infection à Campylobacter a été toujours pathogène chez les plus jeunes. Elle se situe vers le 8ème mois de la vie pour 10% d'entre eux. Les réinfections se font à des distances différentes de l'événement initial en fonction de l'âge. Ce profil d'infection pourrait traduire une compétence immunitaire différente selon l'âge et/ou une immunité acquise au cours du temps suite aux expositions répétées des enfants. L'environnement pourrait avoir un effet indirect dans l'entretien d'une immunité protectrice s'exprimant par un taux élevé d'infection asymptomatique. Il apparaît nécessaire de poursuivre des études de cohorte dans des zones à plus fort risque de transmission avec des données immunologiques car la compréhension actuelle des interactions entre l'hôte, le Campylobacter et l'environnement ne permet pas d'expliquer la variabilité de l'expression clinique de l'infection. / Diarrheal diseases remain a major cause of infant mortality in developing countries (DCs). Due to the lack of technical platforms, the etiologic diagnoses are rarely made and treatments are then probabilistic. In Madagascar data on diarrhea are often fragmented and old. The sentinel surveillance network developed by the Institut Pasteur of Madagascar from 2007 allowed us to study the spatial and temporal distribution of consultations for diarrhea. But this syndromic surveillance cannot be coupled to biological monitoring for many diseases. In this context, we have no information on the causative agents of diarrhea. To achieve the coupling of syndromic and etiologic data, we performed a case-control study conducted in 2008-2009 in children less than 5 years in 14 districts. We have identified at least one pathogen in more than half of the children (55%), with a predominance of parasitic etiologies (37.2% diarrhea), followed by bacteria (15%) and viruses (6.7% rotavirus). Parasites were the only etiologies for which pathogenicity has been demonstrated. Among the bacterial etiologies, Campylobacter infection was the most common (9.5%). To better understand the role of Campylobacter in the occurrence of diarrhea in children and analyze the effect of environmental factors, we initiated and coordinated a dynamical cohort study including of children before the age of 24 months and followed up till the age of 36 months in Moramanga site, where the prevalence of Campylobacter was highest during the 2008 study (20.6%). Diarrhea surveillance was conducted two times per week and asymptomatic carriers assessed at baseline and every 2 months. A family study has been implemented and bi-annual stool follow-up in poultry population, water points and community drinking water for families. Campylobacter monitoring in poultry focused on rectal swabs. From January 2010 to May 2012, 508 children - corresponding to 256,346 child days -participated in the study. The overall prevalence of Campylobacter isolation was 9.3%. More than two fifths of children (43.3%) had at least one episode of Campylobacter during follow-up. The annual incidence of diarrhea and symptomatic infections were low, respectively 0.7 episodes / child and 5.8 episodes /100 children, can be explained by the low level of environmental exposure of children. We have studied the role of host factors such as age. The peak of Campylobacter infection is between 18 to 29 months, the diarrhea between 6 to 11 months then decreases. The first Campylobacter infection was always pathogen in the youngest children. It happens to the eighth month of life for 10% of them. Reinfections are at different distances from the initial event according to the age. This pattern of infection may reflect a variation of the immune competence according the age and / or acquired immunity over time after repeated exposure of the children. The local environment may have an indirect impact on maintaining protective immunity expressed by a high rate of asymptomatic infection. However, it is necessary to continue cohort study with immunologic data in a high risk transmission area as the current understanding of the interactions between the host, the environment and Campylobacter does not explain the variability of the clinical expression of infection.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-09-22T14:16:52Z No. of bitstreams: 1 monicacoutoguedessejanesdarocha.pdf: 2791889 bytes, checksum: beaef089c36fe081bd7b02079c3c2045 (MD5) / Approved for entry into archive by Diamantino Mayra (mayra.diamantino@ufjf.edu.br) on 2016-09-26T20:29:42Z (GMT) No. of bitstreams: 1 monicacoutoguedessejanesdarocha.pdf: 2791889 bytes, checksum: beaef089c36fe081bd7b02079c3c2045 (MD5) / Made available in DSpace on 2016-09-26T20:29:42Z (GMT). No. of bitstreams: 1 monicacoutoguedessejanesdarocha.pdf: 2791889 bytes, checksum: beaef089c36fe081bd7b02079c3c2045 (MD5) Previous issue date: 2010-04-29 / A doença diarreica aguda (DDA) representa uma das principais causas de morbimortalidade infantil e desnutrição nos países em desenvolvimento, superada apenas pela pneumonia. A mortalidade global por diarreia em menores de 5 anos, em 2009, foi estimada em 1,5 milhão. No Brasil, em 2008, a DDA foi responsável por 7,2% das hospitalizações e 2,5% das mortes em crianças nessa faixa etária. O conhecimento da prevalência e dos fatores de risco associados à hospitalização e gravidade do episódio diarreico é fundamental no controle da morbimortalidade. Tais fatores podem ser explicados dentro de um modelo multicausal que inclui uma extensa quantidade de variáveis socioeconômico-demográficas, biológicas e culturais inter-relacionadas. A importância de cada fator envolvido varia de acordo com as características da população estudada e sua identificação contribui de maneira efetiva para o conhecimento ecoepidemiológico da DDA, auxiliando na elaboração de medidas preventivas que contribuam para diminuir os custos diretos e indiretos com a doença. Os objetivos deste estudo foram determinar a prevalência da DDA como causa de hospitalização em pacientes menores de 6 anos e avaliar a associação entre variáveis demográficas, epidemiológicas e clínicas e a gravidade do episódio diarréico. Trata-se de um estudo retrospectivo, transversal, realizado no período de janeiro de 2005 a dezembro de 2008. Foram avaliados 6.201 prontuários de crianças de 0 a 6 anos de idade, hospitalizadas em duas instituições públicas no município de Juiz de Fora - Minas Gerais. Diarreia aguda foi definida como presença de pelo menos três evacuações líquidas ou de consistência amolecida, em 24 horas, por no máximo 14 dias. Os pacientes com diarreia aguda foram divididos em dois grupos, de acordo com a intensidade do quadro e foi considerado diarreia grave um período de hospitalização maior ou igual a quatro dias. Os dados epidemiológicos e clínicos dos pacientes foram avaliados e comparados através da aplicação do Teste Qui-Quadrado e do modelo de regressão logística binomial. A prevalência de internações por diarreia aguda foi de 8,4%. Os fatores que mostraram associação significativa com gravidade do episódio diarreico foram: idade inferior a 6 meses (n = 126, p = 0,01, OR = 2,762); início da doença no outono (n = 197, p = 0,033, OR = 1,742), presença de febre(n = 333, p = 0,017, OR = 1,715) e uso de antibioticoterapia durante a internação (n = 267, p = 0,000, OR = 3,872). Neste estudo, DDA foi a terceira causa de internação em crianças abaixo dos 6 anos no município de Juiz de Fora. Baixa idade (inferior ou igual a 6 meses), febre, uso de antibiótico na internação e início do episódio diarreico no outono são fatores de risco associados ao maior tempo de hospitalização. / Acute diarrheic disease (ADD) is one of the main causes of childhood morbimortality and malnutrition in developing countries, second only to pneumonia. Diarrhea overall mortality of children under 5 years of age was estimated to be 1.5 million in 2009. In Brazil, diarrhea accounted for 7.2% of hospitalizations in 2008, being responsible for 2.5% of all deaths of children under 5 years of age. Knowing the prevalence and risk factors associated with need of hospitalization and severity of acute diarrhea is essential to control morbidity and mortality. These factors may be explained by a multi-causal model of the inter-relation of socioeconomic, demographic, biological and cultural variables. The importance of each factor involved varies according to the characteristics of the population studied and identify them can effectively contribute to a greater understanding of the eco-epidemiologic patterns of ADD, and for the adoption of preventive measures that help to reduce the direct and indirect costs with the disease. The objectives of this study were to determine the prevalence of ADD as a cause of hospitalization in patients under 6 years of age and investigate the association between demographic, epidemiological and clinical determinants and the severity of the diarrheic episodes. This is a retrospective, cross-sectional study, during the period from January-2005 through December-2008. 6,201 files from children from 0 to 6 years of age, hospitalized in two public institutions, in the municipality of Juiz de Fora – Minas Gerais, were assessed. Acute diarrhea was defined as the presence of at least three evacuations of liquid or loose stools, within 24 hours, for a maximum period of 14 days. The patients with acute diarrhea were divided in two groups, according to disease severity, severe diarrhea being considered whenever hospitalization lasted for at least four days. Epidemiologic and clinical data were assessed and compared through the application of the chi-squared test and the binomial logistic regression model. The prevalence rate for admission due to acute diarrhea was 8.4%. The factors significantly associated with the severity of the diarrheic episode were: age under 6 months (n = 126, p = 0.01, OR = 2.762); disease onset during fall (n = 197, p = 0.033, OR = 1.742), presence of fever (n = 333, p = 0.017, OR = 1.715) and antibiotic use during hospitalization (n = 267, p = 0.000, OR = 3.872). In this study, diarrhea is the third most common cause of hospitalization among children under 6 years of age in Juiz de Fora. Young age (under or equal to 6 months), fever, antibiotic use during hospitalization and disease onset during fall are risk factors associated with longer hospital stay.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Campylobacter jejuni e Campylobacter coli sÃo importantes agentes etiolÃgicos de doenÃa diarrÃica na populaÃÃo mundial. A infecÃÃo por Campylobacter sp. à usualmente identificada por cultivo microbiolÃgico que leva aproximadamente 72 horas para identificaÃÃo do gÃnero. Nosso objetivo principal foi pesquisar a prevalÃncia de C. jejuni e C. coli em populaÃÃo infantil, com idade entre 2-36 meses, da Ãrea urbana de Fortaleza/CE, Brasil, em estudo do tipo epidemiolÃgico observacional caso-controle, utilizando, como ferramenta de detecÃÃo, a reaÃÃo em cadeia da polimerase (PCR). Outros objetivos consistiram em: investigar o impacto nutricional da infecÃÃo (casos) ou da colonizaÃÃo (controles) por Campylobacter sp.; determinar a presenÃa de trÃs genes de virulÃncia para a toxina citoletal distensora (CDT) de C. jejuni e avaliar a ocorrÃncia de inflamaÃÃo intestinal nas infecÃÃes causadas por Campylobacter sp. A populaÃÃo estudada consistiu de 83 casos e 83 controles, sendo os casos, crianÃas com histÃrico de diarrÃia nos 14 dias pregressos à seleÃÃo para o estudo. Foram avaliados parÃmetros sÃcio-econÃmicos atravÃs de questionÃrio epidemiolÃgico. Medidas antropomÃtricas foram coletadas para determinaÃÃo de escores-z no intuito de avaliar o perfil nutricional das crianÃas. A detecÃÃo de Campylobacter nas amostras congeladas foi realizada por ensaio imuno-enzimÃtico (ELISA) e PCR. Pela PCR tambÃm investigamos a presenÃa dos genes cdtA, cdtB e cdtC da CDT de C. jejuni. A avaliaÃÃo da inflamaÃÃo intestinal foi realizada pela pesquisa de lactoferrina fecal (LFF), atravÃs de ELISA semiquantitativa. Foi detectado, por PCR, C. jejuni em 9,6% dos casos (8/83) e 7,2% dos controles (6/83). C. coli foi detectado em 6,0% dos casos (5/83) e 1,2% dos controles (1/83). Os genes cdtA, cdtB e cdtC foram encontrados em 50% das amostras hipO+ (7/14). Houve diferenÃa significativa (p<0,05) dos escores WAZ e WHZ entre casos e controles portadores de C. jejuni, sendo que casos portadores apresentaram mÃdia inferior de WAZ e WHZ, quando comparados com os controles portadores. No grupo Casos, os portadores de C. jejuni apresentavam valor mÃdio de WHZ inferior ao valor mÃdio apresentado pelos casos nÃo-portadores. Mais de 80,0% das crianÃas estudadas apresentaram inflamaÃÃo intestinal caracterizada por elevados nÃveis de LFF, independente da presenÃa de diarrÃia e Campylobacter sp. Em conclusÃo, nossos achados corroboram dados da literatura cientÃfica relacionados à prevalÃncia de C. jejuni e C. coli na populaÃÃo infantil, existÃncia de portadores assintomÃticos e associaÃÃo entre a detecÃÃo do microorganismo e desnutriÃÃo. AlÃm disso, nossos dados apontam para ocorrÃncia de variabilidade genÃtica dentre as cepas de C. jejuni detectadas na populaÃÃo estudada em relaÃÃo à presenÃa ou ausÃncia dos genes de CDT. / Campylobacter jejuni and Campylobacter coli are important etiologic agents of worldwide diarrheal disease. Campylobacter sp. infection is usually identified by a 72 hour microbiological culture that identifies the genus of the responsible organism. Our main goal was to investigate the prevalence of C. jejuni and C. coli in children, aged 2-36 months, from urban Fortaleza, CE, Brazil, in an observational epidemiological case-control study using, as a tool of detection, the polymerase chain reaction (PCR). Our other goals were to investigate the nutritional impact of infection (cases) or colonization (controls) for Campylobacter sp., to determine the presence of three virulence genes of C. jejuni cytolethal distending toxin (CDT), and to evaluate the occurrence of inflammation in intestinal infections caused by Campylobacter sp. The study population consisted of 83 cases and 83 controls, where the cases consisted of children with a history of diarrhea in the 14 days prior to selection for the study. We assessed socioeconomic parameters through an epidemiological questionnaire. Anthropometric measurements were collected to determine z-score parameters for assessing the nutritional status of the children. Detection of Campylobacter from frozen samples was performed by enzyme-linked immunosorbent assay (ELISA) and PCR. Also, using PCR technology, we investigated the presence of C. jejuni genes cdtA, cdtB and cdtC. Intestinal inflammation was assessed by semi-quantitative ELISA detection of fecal lactoferrin (LFF). PCR technology detected C. jejuni in 9.6% of the cases (8/83) and 7.2% of the controls (6/83), while C. coli was detected in 6.0% of the cases (5/83) and 1.2% of the controls (1/83). CDT genes were found in 50% of hipO+ samples (7/14). There was a significant difference (p <0.05) in the weight for age z-scores (WAZ) and the weight for height z-scores (WHZ) between case and control carriers of C. jejuni, where case carriers showed lower average WAZ and WHZ than control carriers. Moreover, in the case group, carriers of C. jejuni showed a lower WHZ average than that of non-carrier cases of C. jejuni. More than 80.0% of the children studied had intestinal inflammation characterized by high levels of LFF regardless of the presence of diarrhea and Campylobacter sp. In conclusion, our findings corroborate data in the scientific literature related to the prevalence of C. jejuni and C. coli in pediatric populations, the existence of asymptomatic carriers and an association between the detection of the microorganism and malnutrition. In addition, our data suggest a genetic variability among the strains of C. jejuni detected in the study population, related to presence o absence of CDT genes.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-06-21T13:51:59Z No. of bitstreams: 1 vivianhonoratobarletta.pdf: 2632443 bytes, checksum: c92921b16b55178bf7a44b922bd843ef (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-08-07T19:10:07Z (GMT) No. of bitstreams: 1 vivianhonoratobarletta.pdf: 2632443 bytes, checksum: c92921b16b55178bf7a44b922bd843ef (MD5) / Made available in DSpace on 2017-08-07T19:10:07Z (GMT). No. of bitstreams: 1 vivianhonoratobarletta.pdf: 2632443 bytes, checksum: c92921b16b55178bf7a44b922bd843ef (MD5) Previous issue date: 2011-02-24 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Os norovírus (NoV) são importantes agentes etiológicos, responsáveis por surtos e casos esporádicos de doença diarréica aguda, que acometem indivíduos de todas as idades. A partícula viral não apresenta envelope e o material genético é constituído por uma molécula de RNA de fita simples, de polaridade positiva. Pertencem à família Caliciviridae, gênero Norovirus e estão classificados em cinco genogrupos (GI–V), sendo que os NoV humanos estão agrupados nos genogrupos I, II e IV e destes, os NoV do genogrupo II e genótipo 4 (GII.4) são os mais comumente encontrados, em todo o mundo. Apesar da associação destes vírus com a doença diarréica aguda estar bem documentada na literatura mundial, no Brasil, os trabalhos são escassos e restritos aos grandes centros e adjacências. Assim, considerando-se o pouco conhecimento sobre os norovírus e a inexistência de dados epidemiológicos na cidade de Juiz de Fora, MG, foi realizado o presente estudo, cujos objetivos foram a detecção e caracterização molecular de amostras de NoV, associadas a casos esporádicos de doença diarréica aguda infantil, bem como a avaliação da influência de fatores climáticos e demográficos na ocorrência destas infecções. De janeiro de 2008 a dezembro de 2009, 218 espécimes fecais foram analisados para a presença de NoV, por RT-PCR convencional, todos obtidos de crianças de 0 a 12 anos de idade, proveniente de atendimentos ambulatoriais (89,45%) e hospitalizados (10,55%). Foram detectadas 20 (9,17%) amostras positivas e observou-se uma tendência de sazonalidade das infecções no período da estação seca, no ano de 2008, fato que não se repetiu em 2009. A maioria das amostras positivas foi detectada em crianças na faixa de 0 a 36 meses e não houve correlação, estatisticamente significante, entre a ocorrência das infecções e o sexo. Das 20 amostras detectadas, 19 foram caracterizadas como NoV GII e 1 como NoV GI. O sequenciamento parcial do genoma e a análise filogenética das amostras selecionadas, revelou a presença de NoV dos genótipos GII.4 e GII.6, que cocircularam nos dois anos do estudo. As amostras NoV GII.4, detectadas em Juiz de Fora, apresentaram maior similaridade de nucleotídeos e de aminoácidos com aquelas que circularam no estado do Rio de Janeiro nos anos de 2006, 2007 e 2008. A análise filogenética das amostras NoV GII.6 detectadas em Juiz de Fora, associada à alta similaridade das sequências de nucleotídeos e aminoácidos, mostrou que estas foram mais proximamente relacionadas com a amostra NoV GII.6 (GU132461/2007), detectada no estado do Rio de Janeiro em 2007, fatos que, aliados à proximidade geográfica de ambas as cidades, sugerem uma possível linhagem comum entre as mesmas. Este levantamento epidemiológico permitiu constatar a presença e circulação de NoV na população infantil de Juiz de Fora, MG, demonstrando sua importante participação como agente etiológico das diarreias agudas, também nesta comunidade / Noroviruses (NoV) are important etiological agents responsible for outbreaks and sporadic cases of acute diarrhea in individuals of all ages. The viral particles are nonenveloped with and the genome is composed of a positive single-stranded RNA. Norovirus belongs to the Caliciviridae family, Norovirus genus and are classified into five genogroups (GI-V), with GI, GII and GIV being found in human and among them, the NoV GII genotype 4 (GII.4) are the most commonly found worldwide. In Brazil, norovirus surveys are realized mainly in research institutes, carried out in the biggest centers and surroundings. Thus, considering the little knowledge about these viruses and the lack of epidemiological data on this viral infection in the Juiz de Fora city, MG state, it was performed this study, which aimed to detect and characterize the NoV samples, associated with sporadic cases of acute infantile diarrhea, as well as asses the influence of climatic and demographic factors in the occurrence of these infections. Between January 2008 to December 2009, 218 fecal specimens were analyzed for the presence of NoV by conventional RT-PCR, all obtained from children 0-12 years of age, from outpatient (89.45%) and inpatients (10.55%). We detected 20 (9.17%) positive samples and there was a tendency for seasonal infections during the dry season in 2008, a fact which was not repeated in 2009. The biggest number of positive samples were detected in children aged 0 to 24 months and there was no statistically significant correlation between the occurrence of infections and sex. Of the 20 samples detected, 19 were characterized as NoV GII and 1 as NoV GI. The partial genome sequencing and phylogenetic analysis of selected samples revealed the presence of NoV genotypes GII.4 and GII.6, which co-circulated in the two years of study. Samples NoV GII.4 detected in Juiz de Fora, showed greater similarity of nucleotides and aminoacids with those that circulated in the state of Rio de Janeiro during 2006, 2007 and 2008. Phylogenetic analysis of the samples GII.6 NoV, detected in Juiz de Fora, associated with the high similarity of nucleotide and amino acid sequences showed that they were most closely related to the sample GII.6 NoV (GU132461/2007) detected in the state of Rio de Janeiro in 2007. This fact associated with the geographical proximity of both cities, suggesting a possible common lineage between them. This epidemiological survey revealed the presence and circulation of NoV in the infantile population of Juiz de Fora, MG, demonstrating its important role as an etiologic agent of acute diarrhea, also in this community.