Dissertations / Theses on the topic 'Flavivirus'
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Shomiad, Shueb Rafidah Hanim. "Contribution of different components of innate and adaptive immunity to severity of flavivirus-induced encephalitis in susceptible and resistant hosts." University of Western Australia. School of Biomedical, Biomolecular and Chemical Sciences, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0199.
Full textKhou, Cécile. "Etude du neurotropisme des Flavivirus neuropathogènes." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCC305/document.
Full textNeuropathogenic Flaviviruses, such as Japanese encephalitis virus (JEV), West Nile virus (WNV), yellow fever virus (YFV) and Zika virus (ZIKV), cause neurological diseases. These diseases are due to viral infection of central nervous system (CNS) cells. The CNS is a privileged organ, isolated from pathogenic agents by a barrier between the blood and the barrier, called the blood-brain barrier (BBB). Neuropathogenic Flaviviruses which can cross this BBB in order to reach their target cells in the CNS, are neuroinvasive. This study aims at understanding the cellular mechanisms by which YFV and JEV Flaviviruses cross the BBB and the effects of viral infection by WNV and ZIKV of the CNS cells during neocortex development.YFV is a hepatrotopic virus, which mostly infects the liver and the kidneys. The two live-attenuated vaccines against YFV, the FNV (for French Neurotropic Virus) vaccine and the 17D vaccine, were obtained empirically by several passages in suckling mouse brain of YFV virulent strains. These vaccines do not cause any disease targeting the liver or the kidneys, but can sometimes cause post-vaccine encephalitis. These encephalitis cases suggest that the vaccine strains have become neurovirulent and neuroinvasive. Due to high risks of post-vaccine encephalitis, the FNV vaccine use was discontinued in the 1980s.JEV is a neurotropic virus, causing acute encephalitis in South East Asia. To date, there is a live-attenuated vaccine against JEV, the JEV SA14-14-2 vaccine, which was obtained empirically by several passages in primary hamster kidney cells. This vaccine is less neurovirulent and less neuroinvasive than JEV virulent strains in mouse model, and it protects against JEV infections. However, some cases of post-vaccine encephalitis were reported. It thus seems that, in some cases, the vaccine strain JEV SA14-14-2 is able to cross the BBB and infect neuronal cells.The recent ZIKV epidemics in French Polynesia and South America were linked to an increase in the number of congenital malformations, rising questions regarding the capacity of a Flavivirus to induce CNS congenital malformations.In this study, we have identified cellular mechanisms involved in Flavivirus neuroinvasion and studied the effect of ZIKV and WNV infection of neuronal cells under development.To study CNS development, we have infected mouse embryos brain slices. We were able to show that ZIKV has a preferential tropism for neuronal progenitors, whereas WNV has a preferential tropism for neuronal cells. We also show that infection of neuronal progenitors by ZIKV impairs the cell life cycle, whereas no effect on the cell life cycle was observed for WNV-infected cells. Studies on apoptosis induction did not show any difference between both viruses at early time points of infection.To study Flavivirus neuroinvasion, we have used an in vitro model of BBB composed of human endothelial hCMEC/D3 cells that can form tight junctions. These cells were cultivated on Transwell inserts and placed above human neuronal cells. Using this system, we show that YFV FNV cross the BBB more efficiently than YFV 17D, suggesting that YFV FNV is more neuroinvasive than YFV 17D. This observation can explain the higher post-vaccine encephalitis risks associated with YFV FNV vaccine compared to YFV 17D vaccine. We also confirmed that JEV SA14-14-2 vaccine strain is less neuroinvasive than JEV RP9.We also examined how JEV crosses the BBB and the endothelial cell response following JEV treatment. We show that both JEV RP9 and SA14-14-2 are able to cross the BBB without infecting its endothelial cells and without disrupting the BBB. Preliminary results suggest that JEV RP9, but not JEV SA14-14-2, crosses the BBB by dynamin-dependant transcytosis. Transcriptomic analysis of endothelial cells treated by either virus show slight, but significant, differences in regulation of genes implicated in several pathways associated with CNS diseases
Lequime, Sébastian. "Interactions flavivirus-moustiques : diversité et transmission." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066081/document.
Full textFlaviviruses are RNA virus among which some are arboviruses transmitted between vertebrate hosts and arthropod vectors, like mosquitoes. The interaction with mosquitoes is key in the biology of flaviviruses because it influences their genetic diversity and transmission. However, some aspects however are still poorly understood. At the heart of the work presented in this dissertation, strategies based on ‘big data’, both by taking advantage of modern technologies and by compiling older literature, highlighted new aspects of the complex relationships between flaviviruses and mosquitoes. While exploring Anopheles mosquito genomes, we identified and characterized endogenous viral elements of flaviviral origin in Anopheles sinensis and An. minimus, which supports the existence of flaviviruses infecting Anopheles mosquitoes and highlights new aspected of their diversity. Besides, we explored, by deep sequencing, the fine-tuned interaction between genotypes of the mosquito Aedes aegypti and the intra-host diversity of dengue virus 1. Our results showed a strong effect of genetic drift during initial infection, reducing the relative importance of natural selection, and a modulation of the intra-host viral genetic diversity by the mosquito genotype. Finally, we assembled the litterature on arbovirus vertical transmission in the mosquito vector, i.e. from an infected female to her offspring, in order to identify underlying technical and biological predictors. Our results increase our understanding of this transmission mode and the strategies employed by arboviruses to persist in their environment
Lequime, Sébastian. "Interactions flavivirus-moustiques : diversité et transmission." Electronic Thesis or Diss., Paris 6, 2016. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2016PA066081.pdf.
Full textFlaviviruses are RNA virus among which some are arboviruses transmitted between vertebrate hosts and arthropod vectors, like mosquitoes. The interaction with mosquitoes is key in the biology of flaviviruses because it influences their genetic diversity and transmission. However, some aspects however are still poorly understood. At the heart of the work presented in this dissertation, strategies based on ‘big data’, both by taking advantage of modern technologies and by compiling older literature, highlighted new aspects of the complex relationships between flaviviruses and mosquitoes. While exploring Anopheles mosquito genomes, we identified and characterized endogenous viral elements of flaviviral origin in Anopheles sinensis and An. minimus, which supports the existence of flaviviruses infecting Anopheles mosquitoes and highlights new aspected of their diversity. Besides, we explored, by deep sequencing, the fine-tuned interaction between genotypes of the mosquito Aedes aegypti and the intra-host diversity of dengue virus 1. Our results showed a strong effect of genetic drift during initial infection, reducing the relative importance of natural selection, and a modulation of the intra-host viral genetic diversity by the mosquito genotype. Finally, we assembled the litterature on arbovirus vertical transmission in the mosquito vector, i.e. from an infected female to her offspring, in order to identify underlying technical and biological predictors. Our results increase our understanding of this transmission mode and the strategies employed by arboviruses to persist in their environment
Grard, Gilda. "Génomique et évolution des flavivirus transmis par les tiques et découverte d'un nouveau lignage du genre flavivirus." Aix-Marseille 2, 2006. http://www.theses.fr/2006AIX20679.
Full textGollins, S. W. "Mechanisms of flavivirus neutralization and cellular infection." Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355752.
Full textDayaraj, Cecilia. "Molecular and immunological studies on flavivirus virulence." Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279888.
Full textCarney, Jennifer. "Viral Determinants of Flavivirus Neurotropism in Humans." Thesis, University of Liverpool, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.526956.
Full textPacca, Carolina Colombelli. "Screening de novos antivirais inibidores de flavivirus." Faculdade de Medicina de São José do Rio Preto, 2013. http://bdtd.famerp.br/handle/tede/201.
Full textCoordenação de Aperfeiçoamento de Pessoal de Nível Superior
Introduction. Arboviruses, arthropod-borne viruses, are frequently associated with human outbreaks and represent a serious health problem. The genus Flavivirus, which includes both the Yellow Fever Virus (YFV) and Saint Louis Encephalitis Virus (SLEV), are important pathogens that result in high morbidity and mortality rates worldwide. In Brazil, YFV has a sylvatic cycle and occurs annually, despite the efficiency of the vaccine. Saint Louis Encephalitis is an infectious illness that can cause acute fever caused by SLEV, which is widely distributed in the Americas. The emergence of SLEV became a serious concern after the first related outbreak in Brazil in 2006, in the city of Sao Jose do Rio Preto. There is no specific antiviral drug for these viruses, only supporting treatment that can alleviate the symptoms and prevent complications. The need to develop effective and safe antiviral drugs is indispensable for the treatment of these infections. Objective. The aim of this work was to identify new possible antiviral drugs against the arboviruses that can cause acute fever and encephalitis (YFV and SLEV) and to evaluate the capacity of inhibition of these compounds in ABR mice. Material and Methods. Plaque reduction assay, flow citometry, immunofluorescence and cellular viability were used to test the compounds in vitro. ABR mice were inoculated with YFV, and the biological samples were tested for the presence of the virus through the use of plaque reduction assay and qPCR. Neutralization assay was also performed. Results. Treated cells showed efficient inhibition of viral replication at concentrations that presented minimal toxicity to the cells. The assays showed that ftalyl-tiazole and fenoxytiosemicarbazone were more effective, and that they reduced viral replication by 60% and 75% for YFV and SLEV, respectively. The analysis also revealed that the ABR mice inoculated with YFV had histopathological alterations in the liver; however, the samples did not present viral title. Neutralization assay showed a high concentration of antibodies in the serum. Conclusion. The inhibitions of viral replication were confirmed through the use of some assays in vitro, and the effectiveness of the selected compounds show that they are an option in the treatment of these viruses. More detailed studies are needed to determine the mechanism of action of these molecules. The mice were found to have histopathological alterations, which indicates viral infection; however, they also presented with high concentrations of antibodies. More studies about animal models are necessary to make in vivo experiments.
Introdução: Os arbovírus, vírus transmitidos por artrópodes, são freqüentemente associadas a surtos em seres humanos e representam um problema sério de saúde pública. Os vírus pertencentes ao gênero Flavivirus, tais como vírus da Febre Amarela (YFV) e vírus da Encefalite de Saint Louis (SLEV), são importantes patógenos que podem causar alta taxa de morbidade e mortalidade no mundo. No Brasil, YFV é mantido em ciclo silvestre notificados anualmente, a despeito da segurança e eficiência da vacina. A encefalite de Saint Louis é uma doença infecciosa febril aguda causada pelo SLEV amplamente distribuída nas Américas. A emergência do SLEV passou a ser um fato preocupante no Brasil a partir da constatação do primeiro surto no país em 2006, na cidade de São Jose do Rio Preto. Não existe tratamento específico para estas viroses, somente tratamento de suporte para ajudar a aliviar os sintomas e prevenir complicações. Desta forma, há uma grande necessidade de que sejam desenvolvidos antivirais efetivos e seguros para o tratamento destas infecções. Objetivos: O objetivo deste trabalho foi identificar potenciais compostos antivirais contra os arbovírus causadores de doença febril aguda e encefalites (YFV e SLEV) in vitro e avaliar a capacidade de inibição da replicação viral dos compostos in vivo em camundongos ABR. Materiais e Métodos: Para tanto, foram realizados ensaios de redução de placas, citometria de fluxo, imunofluorescencia, bem como testes de viabilidade celular para as analises in vitro. Além disto, camundongos ABR foram inoculados com YFV e seus materiais biológicos testados para a presença de partículas virais por ensaio de redução de placas e qPCR. Adicionalmente, foi realizado ensaio de neutralização do soro dos animais. Resultados: Celulas tratadas com os compostos mostraram eficiente inibição da replicação viral em concentrações que apresentam baixa citotoxicidade. Os ensaios mostraram que derivados de ftalyl-tiazole e fenoxytiosemicarbazone foram os mais eficazes na ação antiviral, apresentando redução de 60% e 75% para YFV e SLEV, respectivamente. Camundongos ABR inoculados com YFV apresentaram alterações histológicas no fígado, entretanto, não foi constatado título viral nas amostras testadas. O ensaio de neutralização mostra altas concentrações de anticorpos no soro dos animais. Conclusões: A inibição da replicação foi comprovada por vários ensaios in vitro evidenciando as moléculas como potentes alternativas para o tratamento dos vírus. Mais estudos são necessários para a determinação do mecanismo de ação destas moléculas. Os camundongos apresentaram alterações histopatológicas sendo um indicativo de infecção, entretanto, apresentam altas taxas de anticorpos. Mais estudos sobre modelo animal são necessários para a realização de ensaios in vivo.
Singethan, Katrin. "Untersuchungen zur Inhibition Paramyxo- und Flavivirus-induzierter Membranfusion." kostenfrei, 2009. http://www.opus-bayern.de/uni-wuerzburg/volltexte/2009/3634/.
Full textCunha, Mariana Sequetin. "Validação e uso de transcrição reversa seguida da reação em cadeia pela polimerase em tempo real (RT-qPCR) para a vigilância e diagnóstico de flavivírus transmitidos por mosquitos circulantes no Brasil." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/10/10133/tde-16102018-113026/.
Full textFlaviviruses are considered a serious threat to public health in many parts of the world, as many are highly pathogenic to humans and animals, such as Yellow Fever virus, West Nile virus, Japanese encephalitis virus and dengue virus, which are capable of causing encephalitis or hemorrhagic fever in their hosts. Many of them have spread to different geographic regions where their circulation had not been detected previously, causing new outbreaks. Diagnosis of these infections is often difficult, due to the large number of symptoms presented, which can be confused with other diseases of different etiological causes. The main direct methods currently used in Brazil for detecting these viruses are intracerebral inoculation in neonatal mice, inoculation in cell cultures and specific RT-PCR. The present work aims to evaluate the sensitivity and validate the detection of viruses belonging to the genus Flavivirus circulating in Brazil through a single real-time RT-PCR reaction and to implement it, both in the diagnostic routine of cases with arbovirus suspicions and in field samples for viral monitoring. Samples of the standard flaviviruses Yellow Fever, Bussuquara, Iguape, Ilheus, Saint Louis Encephalitis, Cacipacore and Zika were quantified by titration by plaque forming units (UFP) or TCID50 to evaluate the detection limits for each of them by RT- qPCR that detects genus Flavivirus. The limits found ranged from 0.01 PFU for Ilheus virus to 1 PFU for Yellow Fever and Iguape viruses and 1x101.6 TCID50 / 100L for the Bussuquara virus. In addition, the present work was able to identify, after cDNA sequencing Zika virus, isolated from a febrile patient, and both Ilheus and Iguape viruses, isolated from different species of Culicidae, and a possible new insect-specific flavivirus, isolated from Aedes mosquitoes collected in Guapiaçu, São Paulo. The Alphaviruses Mayaro and Chikungunya were not amplified. The present protocol shoed high sensitivity and specificity, and therefore it may may be used for the differential diagnosis of the different flaviviruses that occur in Brazil, as well as for viral monitoring studies in sentinel animals and vectors, thus collaborating with public health. It is also possible to detect new flavivirus that are arthopode-specific.
Silva, Jaqueline Raymondi. "Pesquisa de infecções por Flavivírus da encefalite de Saint Louis, Rocio e Oeste do Nilo em cavalos, por inquérito sorológico e isolamento viral." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/17/17147/tde-23062010-150025/.
Full textArboviruses are a serious public health problem in Brazil and, from these, the most important are caused by Flavivirus. Eleven Flavivirus have been described in Brazil. Of these, Saint Louis Encephalitis Virus (SLEV) and Rocio Virus (ROCV) are major public health problems and belongs to the Japanese Encephalitis Serocomplex. West Nile Virus (WNV), introduced in the American continent in 1999, has not yet been detected in Brazil. In this study, it was evaluated the circulation of SLEV, WNV and ROCV in horses, by viral isolation attempts and a serosurvey. Viral isolation attempts were performed in 11 brain tissues of horses from Paraíba state with negative results. It was used for the serosurvey, an IgG-ELISA with recombinant peptides of domain III of SLEV, WNV and ROCV envelope protein as antigens. Sera from 753 animals from São Paulo, Mato Grosso do Sul, Minas Gerais, Rio de Janeiro and Paraíba states were tested, and 271 of them were positive for SLEV (35,98%), 254 for WNV (33,73%) and 144 for ROCV (19,12%). Therefore, this ELISA has been a suitable approach for diagnosis of ancient infections by these viruses. An intense circulation of flaviviruses infecting horses was observed in the study sites. Besides, it was found, for the first time, the presence of WNV in Brazil, infecting horses from all the studied states with the only exception of Minas Gerais. Finally, serosurvey in horses proved to be an appropriate approach for surveillance of Flavivirus infections by SLEV, WNV and ROCV.
Araujo, Marina Reus Tassi de. "Expressão de proteínas recombinantes de vírus do gênero Flavivirus." reponame:Repositório Institucional da UFPR, 2010. http://hdl.handle.net/1884/22380.
Full textGaunt, Michael W. "The epidemiology of louping ill virus and flavivirus evolution." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363978.
Full textLopes, Samuel Franco. "Identificação de Flavivirus em aves silvestres da Amazônia Central." Universidade Federal do Amazonas, 2011. http://tede.ufam.edu.br/handle/tede/4594.
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The Amazon region has the highest biodiversity on the planet, as well as the largest number of arboviruses isolated, mainly due to the great diversity of species of wild vertebrates and hematophagous arthropods. Among the arboviruses, Flavivirus stand out both for producing the highest number of infections and human diseases, such as the severity of these diseases. Moreover, it is known that birds act as reservoir of some poorly studied Flavivirus, such as: Ilheus, Saint Louis Encephalits, Rocio, Cacipacoré and Bussuquara. Despite intensive studies in the brazilian amazon, especially in certain areas of the state of Para, few epidemiological information about most of these viruses were obtained. In this study, a specie of Flavivirus has been identified in whole blood samples from wild birds, captured in-situ (Alter do Chão/PA) and ex-situ (Manaus) by polymerase chain reaction preceded by reverse transcription (RT- PCR) followed by Multiplex-Nested PCR (MN-PCR) tests for species-specific identification. Among the 189 samples, 7(4,23%) were suggestive of Ilheus virus. The diagnostic technique used was effective in identifying the genus Flavivirus in samples of wild birds presenting itself as practical, fast and secure for the identification of brazilian arboviruses. The circulation of enzootic viruses both in captive and free-living birds, increase the role of birds as host in the cycles of transmission of zoonoses.
A Amazônia apresenta os maiores índices de biodiversidade do planeta, assim como o maior número de arbovírus isolados, principalmente em função da grande diversidade de espécies de artrópodes hematófagos e vertebrados silvestres. Entre os arbovírus, destacam-se os Flavivírus tanto por produzirem o maior número de infecções e doenças humanas, como pela gravidade destas doenças. Além disso, sabe-se que as aves atuam como reservatório de alguns Flavivirus pouco estudados como: Ilhéus, Saint Louis, Rocio, Cacipacoré e Bussuquara. Apesar de estudos intensivos realizados na Amazônia brasileira, sobretudo em certas áreas do Estado do Pará, poucas informações epidemiológicas a respeito da maioria desses vírus foram obtidas. Nesse estudo, foi identificada uma espécie de Flavivirus em amostras de sangue total de aves silvestres, capturadas in-situ (Alter do chão/PA) e ex-situ (Manaus/AM) através da reação em cadeia de polimerase conjugada a transcrição reversa (RT-PCR) seguida por multiplex nested-PCR (MN-PCR) para testes de identificação espécie-específicos. Entre as 189 amostras analisadas, foram encontrados 7 (4,23%) amplicons sugestivos do vírus Ilhéus entre as amostras positivas. A técnica de diagnóstico utilizada mostrou-se eficaz para a identificação do gênero Flavivírus em amostras de aves silvestres apresentando-se como uma alternativa prática, rápida e segura para a identificação de arboviroses brasileiras. A circulação enzoótica dos vírus tanto em aves de cativeiro como de vida livre reforçam o papel das aves como hospedeiro nos ciclos de transmissão destas zoonoses.
Moureau, Grégory. "Génomique des Flavivirus : Contribution à l'analyse taxonomique et phylogénique." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM5002.
Full textWithout including the retroviruses, there are in excess of 200 RNA viruses that are recognised human and/or animal pathogens, many of which are considered to be emerging viruses because during recent years they have dispersed beyond their original territories causing epidemics in new regions of the World. The more well known of these emerging viruses include, West Nile virus, chikungunya virus, influenza virus, SARS coronavirus, EV71 virus (the aetiological agent of hand foot and mouth disease), dengue virus, hepatitis C virus, Crimean Congo haemorrhagic fever virus, Rift Valley fever virus, Japanese encephalitis virus and many human enteroviruses from a variety of genera. The combined global morbidity and mortality figures for these viruses add up to 100s of millions per year and the current trend appears to be upwards. This is a depressing statistic when one considers the amazing medical and scientific achievements that we have witnessed during the past decades. The studies described in my thesis were focused on the genus Flavivirus the type species of which is yellow fever virus, another terrifyingly virulent human pathogen that has caused so much suffering in Africa and Latin America during the past 300 to 400 years. This virus continues to cause major epidemics in Africa despite the availability of one of the safest and most effective vaccines with which to control infections due to yellow fever virus. Indeed similar comments can be made in the context of the flavivirus Japanese encephalitis virus in India
Bos, Sandra. "Undestanding the viral molecular factors involved in Zika virus pathogenicity in humans." Thesis, La Réunion, 2019. http://www.theses.fr/2019LARE0005.
Full textZika virus (ZIKV) is an unprecedented epidemiological phenomenon which surprised the world. For many years, it was considered a trivial virus responsible for only a handful of human infections, self-limited and benign, in Africa and Southeast Asia. But then, after decades of silent spread, a first epidemic broke out in Micronesia in 2007 – like a warning signal. A few years later, a sudden Zika outbreak of larger scale occurred in the Pacific islands before reaching Brazil in 2015. During this period, Zika was associated with severe neurological complications, highlighting its serious pathogenic potential for humans. Since its emergence, more than 80 countries and territories have been affected by the ZIKV pandemic, which is now recognized as a neurotropic and teratogenic virus. The association of contemporary ZIKV strains with severe forms of disease in humans, that have never been reported before, has raised the hypothesis of newly acquired pathogenicity. In this regard, my doctoral research aimed to determine whether the scope of the current epidemic was partly facilitated by viral factors that improved ZIKV fitness. To this end, my research project focused on the identification of the viral molecular factors involved in Zika virus pathogenicity in humans based on the development of molecular clones
Defrocourt, Christophe. "L'encéphalite japonaise en 2003 : épidémiologie et nouvelles perspectives de vaccin." Rouen, 2004. http://www.theses.fr/2004ROUEP008.
Full textFulop, Lynda Dorothy. "Molecular analysis of flavivirus genome sequences : implications for virus classification." Thesis, University of Surrey, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308496.
Full textDejarnac, Ophélie. "Molecular and cellular basis of phosphatidylserine receptors mediated flavivirus infection." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCC297/document.
Full textDengue virus (DENV) and ZIKA virus (ZIKV) are two mosquito-borne viruses responsible for important diseases in humans. Since there is currently no vaccine neither antiviral treatment available against these human pathogens, they are two major health concerns. The molecular basis of DENV and ZIKV host cell interactions leading to virus entry are poorly understood, hampering the discovery of new targets for antiviral intervention. Our laboratory recently discovered that TIM (TIM-1 and TIM-4) and TAM (Tyro3 and Axl) proteins, two receptor families that contribute to the phosphatidylserine (PtdSer)-dependent phagocytic removal of apoptotic cells, are DENV entry factors. TIM and TAM receptors mediate DENV infection by interacting with virion-associated PtdSer through a mechanism similar to the recognition and engulfment of apoptotic cells by phagocytes (viral apoptotic mimicry). The general objective of my PhD was to establish a detailed understanding of the molecular mechanisms by which TIM-1 and Axl mediated infection. Using live imaging, we demonstrated that TIM-1 and DENV are co-internalised and TIM-1 play an active role during DENV endocytosis. We showed that TIM-1 cytoplasmic domain is essential for DENV internalization, especially, we identified two lysine residues that are essential for TIM-1 ubiquitination and DENV endocytosis. Proteomic analysis of TIM-1 interacting partners identified STAM, a member of the ESCRT-0 complex involved in intracellular sorting of ubiquitinated cargos, as an essential host factor for DENV infection. Collectively our results establish TIM-1 as the first identified DENV bona fide receptor.Identifying ZIKV entry factors represents a major challenge in the understanding of ZIKV tropism and pathogenesis. We showed that Axl is responsible for ZIKV infection of microglial cells and astrocytes in the human developing brain and primary fibroblasts in human skin, suggesting an important role of this receptor during ZIKV life cycle. We also highlighted the dual role of the Axl receptor in ZIKV infection, which simultaneously promotes viral entry and dampens the innate immune response to facilitate a post entry step of the ZIKV life cycle. In conclusion, this work provided new insights in our understanding of the DENV and ZIKV entry program. Both viruses engage phospholipid receptors for their infectious entry, providing a rational to ascertain therapeutic strategies targeting virion-associated phospholipids
Scaramozzino, Natale. "Flavivirus : étude d'une cible diagnostique, la région NS codant pour la polymérase et d'une cible thérapeutique, la protéase NS3 du virus Langat." Université Joseph Fourier (Grenoble), 2002. http://www.theses.fr/2002GRE19004.
Full textFlaviviruses are responsible for considerable morbidity and mortality and may cause severe encephalitis, hemorrhagic fever, hepatitis, and febrile symptoms in vertebrates, including humans (. . . ). Different p-nitroanilide substrates, defined on canonic sequences for their susceptibility to Ser-protease, were applied to the proteolytic assays of the protein. The highest values were obtained from substrates containing an Arg or Lys (amino acid) residue at the P1 position. This purification method will facilitate the future development of reliable testing procedures for anti-proteases directed to NS3 proteins
Figueiredo, Mario Luis Garcia de. "Identificação de flavivirus infectando culicídeos de 1999 a 2007 no Brasil." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/42/42132/tde-19052010-153321/.
Full textIntroduction: Arbovirus are rodent-borne viruses mostly from Flavivirus (Flaviviridae), Alphavirus (Togaviridae) e Orthobunyavirus (Bunyavirus) genus. Flavivirus, are commonly zoonotic and can cause febrile illness, haemorrhagic fever and encephalitis. Flavivirus outbreaks occur in Brazil and are a major public health problem. We show here a research looking for Flavivirus infections in Culicidae by a RT-PCR using Flavivirus-especific primers and a Multiplex-nested-PCR using specie-specific primers for virus identification. Methods: Culicidae were captured, quantified, identified, pooled based on the specie and frozzen. In the laboratory, the animals were crushed and had the RNA extracted. These extracts were tested by a Flavivirus genus-specific RT-PCR followed by a specie-specific Multiplex-nested-PCR. Results: From 3317 captured adult Culicidae and 571 collected larvae in 4 different regions of Brazil, 246 pools were obtained and from these, Flavivirus indicative amplicons were obtained in 16 (6.5%). Amplicons of dengue type 3 were obtained from 3 pools of Aedes albopictus larvae. It was also possible to obtain indicative amplicons of dengue types 1 and 2 in 13 pools of Haemagogus leucocelaenus, Aedes aegypti and Aedes albopictus. Besides, 4 amplicons had the nucleotides sequenced, confirming the mosquito infection by dengue type 3 and Cacipacoré viruses. Conclusion: The technique combining a Flavivirus genus-specific RT-PCR followed by a specie-specific Multiplex-nested-PCR was suitable for detection of these viruses in the mosquitoes; Flavivirus infecting Culicidae were detected in 6.5% of the analyzed mosquito pools; dengue virus type 1 and type 2 were found infecting Aedes aegypti from Santos (1999), Manaus (2005-2006) and Foz do Iguaçu cities; dengue type 2 virus was found in Aedes albopictus from Santos city (1999) and Manaus city (2005-2006), suggesting that this mosquito could be participating on dengue transmition; dengue type 3 virus was found in Aedes albopictus larvae showing the vertical transmission of this virus; dengue type 1 virus was found infecting Haemagogus sp. what suggests on the existence of a sylvatic maintenance cycle of this virus; Aedes aegypti from Amazonas state were found infeted by Cacipacoré virus.
Nguyen, Jennifer B. "Molecular Mechanisms of Host-Pathogen Interactions in Flavivirus and Hookworm Infection." Thesis, Yale University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3580786.
Full textMicrobial pathogens and their hosts have evolved complex adaptations to ensure their individual survival, resulting in a so-called "molecular arms race." While hosts may have acquired diverse mechanisms to protect themselves from the microbial invader, pathogens have developed elaborate strategies to evade and subvert these defenses. Viruses and hookworms are important pathogens which have evolved to successfully invade and infect their human hosts. Although structural biology has provided significant mechanistic insight into these processes of invasion, many specific host-pathogen interactions and their dynamics have not been well studied or characterized.
The work presented in this dissertation clarifies the mechanisms of cellular entry of one particular family of viruses, the flaviviruses, and discusses strategies for viral clearance by host cells. Additional insight into the role of a cytoplasmic DNA sensor, LRRFIP1, in mediating an innate immune response to non-flavivirus microbial infection is presented. Finally, strategies for the development of small-molecule or peptide inhibitors of virus entry and hookworm infection are proposed.
Caleiro, Giovana Santos. "Investigação da presença do retrovírus da Reticuloendoteliose aviária (REV) e do anticorpo IgG do vírus Oeste do Nilo (WNV) em aves." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/99/99131/tde-04092018-090320/.
Full textBirds can carry a large number of pathogens. The migratory birds are most responsible for the spread of infectious agents due to long distance travels. Among these pathogens, the most notable are viruses, such as the avian Reticuloendotheliosis retrovirus (REV), widely distributed; and the West Nile virus (WNV), a reemerging zoonotic disease. The main symptoms of avian reticuloendotheliosis include anemia, Runting\'s disease and acute nonneoplastic syndrome. The etiological agent of West Nile fever is Flavivirus West Nile (WNV). Birds are their definitive hosts and humans are accidental hosts, which generaly present febrile symptoms, but at less proportion,, meningitis and encephalitis. Mosquitoes of the genus Culex and Aedes spp are the main vectors of the virus. Differently from the REV that has no evidence of its circulation in Brazil, there is evidence of WNV in birds and horses and more recently in humans. The objective of this work was to investigate the presence of REV and WNV in wild birds and captive birds from the city of São Paulo and Northern from Pará State. Blood, serum and cloacal swab were collected, resulting in more than 1000 samples. Through molecular techniques it was possible to detect the presence of REV in 74 samples (16%), all from the State of Pará. The partial sequencing of these samples and their phylogeny suggested that the migration of US-Brazil may have been the route for the virus entry. Through anti-WNV IgG ELISA, 4 samples from São Paulo were positive. We present the first evidence of REV in the country and suggest the presence of WNV in the state of São Paulo.
Cruz, Ana Cecilia Ribeiro. "Caracterização Molecular e Biológica do vírus dengue circulante no Brasil." reponame:Repositório Institucional da FIOCRUZ, 2005. https://www.arca.fiocruz.br/handle/icict/4111.
Full textMade available in DSpace on 2012-05-31T16:28:56Z (GMT). No. of bitstreams: 1 ana_cecilia_r_cruz_ioc_bp_0001_2005.pdf: 4732352 bytes, checksum: ea13b3487709eb14b3bda0c2d649e513 (MD5) Previous issue date: 2005
Fundação Oswaldo Cruz.Instituto Oswaldo Cruz. Rio de janeiro, RJ, Brasil
A febre do dengue está amplamente distribuída por todas as áreas tropicais do mundo. Em certas áreas endêmicas, as formas graves da doença, febre hemorrágica do dengue (FHD) e síndrome de choque do dengue (SCD), ocorrem com freqüência. Outras manifestações clínicas, como, por exemplo, encefalopatias, encefalites, mielite transversa, também tem sido observadas. O nosso objetivo foi a caracterização genética e biológica de amostras de vírus VDEN2 e 3, com ênfase no caráter de neurovirulência do vírus VDEN2. As amostras de VDEN 2 e 3 utilizadas foram isoladas na Serviço de Arbovírus do Instituto Evandro Chagas a partir de soro de pacientes com quadro clínico de dengue (FD e FHD) e manifestações neurológicas. Os vírus padrão foram o VDEN2 Nova Guiné C e 44-2, VDEN3 H87. As 11 seqüências do vírus VDEN2 quando comparados entre si e com 16 outras seqüências do VDEN2 apresentaram percentual médio de identidade nucleotídica e aminoácido de 89,5 e 99,8% respectivamente. Os estudos filogenéticos realizados mostram os isolados brasileiros pertencem ao genótipo III de origem Asiática. As 10 seqüências do vírus VDEN3 quando comparados entre si e com 16 outras seqüências do VDEN3 apresentaram percentual médio identidade nucleotídica e aminoácido de 89,6 e 100% respectivamente.Os estudos filogenéticos realizados mostram que estão agrupados ao genótipo III também de origem Asiática. O virus VDEN2 isolado a partir de caso mielite transversa (Bel61082) foi caracterizado pelo sequenciamento nucleotidico da região estrutural assim como em testes de neurovirulência em camundongos recém-nascidos. A susceptibilidade de culturas primárias de neurônios e astrócitos, células de glioma humano, também foi estudada para fins de caracterização do caráter neurovirulento do vírus.O estudo de neurovirulência em infecção de camundongo mostrou sinais aparentes de doença apenas após a inoculação da cepa NGC, mas a replicação do vírus Bel 61082 pode ser detectada por RT-PCR em suspensão de cérebro de camundongo. Obtivemos evidências experimentais de apoptose nas células neuronais infectadas com VDEN2 NGC e Bel61082. No sequenciamento nucleotídico, a principal alteração observada está localizada na proteína M 28, região esta conhecida como pró-apoptótica.
The dengue fever is widely distributed in all tropical areas of the world. In certain endemic areas, severe disease, dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS), occur frequently. Other clinical manifestations such as, for example, encephalopathies, encephalitis, transverse myelitis, has also been observed. Our objective was to characterize genetic and biological samples of viruses VDEN2 and 3, with emphasis on the neurovirulence of the virus VDEN2. The samples of DENV 2 and 3 used were isolated in the Service of the Instituto Evandro Chagas Arboviruses from the serum of patients with clinical dengue (DF and DHF) and neurological manifestations. Viruses were standard VDEN2 New Guinea C and 44-2, VDEN3 H87. The 11 sequences of the virus VDEN2 compared among themselves and with 16 other sequences showed VDEN2 average percentage of nucleotide and amino acid identity of 89.5 and 99.8% respectively. Phylogenetic studies performed show the Brazilian isolates belonged to genotype III of Asian origin. The 10 sequences of the virus VDEN3 compared among themselves and with 16 other sequences showed VDEN3 average percentage nucleotide and amino acid identity of 89.6 and 100% respectively.The phylogenetic studies carried out show that they are grouped to genotype III also of Asian origin. The virus isolated from VDEN2 case transverse myelitis (Bel61082) was characterized by nucleotide sequencing of the framework region as well as tests neurovirulence in mice newborn. The susceptibility of primary cultures of neurons and astrocytes, human glioma cells was also investigated for the characterization of the character neurovirulent vírus.O study of infection in mouse neurovirulence showed no apparent signs of disease after inoculation only NGC strain, but virus replication 61,082 Bel can be detected by RT-PCR on mouse brain suspension. We obtained experimental evidence of apoptosis in neuronal cells infected with NGC and VDEN2 Bel61082. In nucleotide sequencing, the main change observed is located at 28 M protein, an area known as pro-apoptotic.
COLE, E. R. "Estudo Fitoquímico do Óleo Essencial dos Frutos da Aroeira (Schinus terebinthifolius RADDI) e Sua Eficácia no Combate ao Dengue." Universidade Federal do Espírito Santo, 2008. http://repositorio.ufes.br/handle/10/4634.
Full textO dengue é considerado a mais importante das arboviroses humanas, constituindo atualmente um dos principais problemas de Saúde Pública no mundo. A doença é causada por um vírus do gênero Flavivirus, com quatro diferentes sorotipos, transmitidos por mosquitos do gênero Aedes, sendo o Aedes aegypti seu principal vetor. O controle do vetor por meio de inseticidas sintéticos figura como a principal medida adotada no combate a doença, uma vez que não existem vacinas efetivas contra os diferentes sorotipos do vírus. Os inseticidas, apesar de eficazes, apresentam sérios problemas relacionados ao seu uso, dentre os quais podem ser destacados os danos ambientais, a toxicidade para uso humano e o risco de desenvolvimento de larvas e adultos resistentes.
Henriques, Dyana Alves. "Caracterização molecular de arbovírus isolados da fauna diptera nematocera do Estado de Rondônia (Amazônia ocidental brasileira)." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/42/42132/tde-27032009-124003/.
Full textThe Rondônia state has an area with rich arthropods diversity although the knowledge about the arboviruses transmition for these species is poor. The present work aimed to detect arboviruses through RT-PRC and RT-PCR Duplex in the diptera species collected in the region as well as their characterization through the sequence reaction. The RT-PRC and RT-PCR Duplex detected the Mayaro and Oropouche virus suspensions until 104 e 101 TCID50/mL respectively, although it was negative for the Dengue 2 virus in pools containing less than three infected mosquitoes. The endogenous control was detected in 66,8 % of samples and from pools containing from one to three mosquitoes the detection rate was approximately half from that obtained from pools with 11 to 15 mosquitoes. Oropouche virus was found in 0,66 % of pools and Cacipacore virus also in 0,66 % of pools. Oropouche virus was detected in Coquillettidia sp. and Deinocerites sp. while Cacipacoré virus was found in Anopheles sp. and Culex sp. The techniques allowed the detection of examined arboviruses in the pools collected from Rondonia.
Ottendorfer, Christy L. "Impact of West Nile virus on the natural history of St. Louis encephalitis virus in Florida." [Tampa, Fla] : University of South Florida, 2008. http://purl.fcla.edu/usf/dc/et/SFE0002452.
Full textBeck, Cécile. "Nouvelles stratégies diagnostiques et thérapeutiques contre les flavivirus neurotropes en médecine vétérinaire." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS083/document.
Full textFlaviviruses with a major impact in veterinary medicine are widely distributed (e.g. West Nile fever (WNF) has spread across the five continents and Japanese Encephalitis (JE) is reported in South-East Asia) and are mainly responsible for neurological diseases in humans and/or horses.After flavivirus infection, viremia in mammal hosts is generally short and consequently indirect methods are mostly used to diagnose flavivirus infections. However, frequent spatial overlapping in their circulation areas renders the interpretation of serological assays difficult. Indeed, cross-reactions between flaviviruses are observed in rapid serological tests such as in ELISA and immunofluorescence assays (IFA). Serological assay results should thus be confirmed by the tedious comparative virus neutralization test (VNT) using a panel of viruses known to circulate in the area. Moreover, the risk of emergence of new flaviviruses such as reported recently with the Zika virus in Brazil or in North America should be considered when studying flavivirus epidemiology.In the first section, a new strategy aiming at improving the serological diagnosis of flavivirus infections was developed using the multiplexing capacity of microsphere immunoassays (MIA). The flavivirus soluble envelope (sE) glycoprotein ectodomain is composed of three domains (D), e.g. DI, DII and DIII, with EDIII containing virus-specific epitopes. Recombinant EDIIIs of different flaviviruses were synthesized in the Drosophila S2 expression system. The microspheres coupled with rEDIIIs were assayed with equine and ovine sera from natural and experimental flavivirus infections or non-immune samples. Very encouraging results have been obtained and this innovative multiplex immunoassay based on flavivirus rEDIIIs appears to be a powerful alternative to ELISAs and VNTs for veterinary diagnosis of flavivirus-related diseases.MIA with WNV nonstructural 1 protein were also implemented to differentiate Infected from Vaccinated Animals (DIVA). Such a DIVA approach was only successful when horses had been immunized with a recombinant canarypox vaccine, while horses receiving inactivated WNV vaccine developed immune responses close to the ones induced after natural infection.Another pitfall in veterinary medicine is the lack of therapeutics for viral diseases and specifically for flaviviruses. The therapeutic arsenal is indeed rather limited and animals are generally administered supportive treatments only. In the second part, the results of the in vitro testing of a broad spectrum antiviral named sr1057 on WNV and JEV replication are presented. This chemical, identified from a unique screening strategy developed by Pasteur Institute, is probably targeting the host cell and was found to inhibit the replication of varied RNA and DNA viruses belonging to different virus families. The sr1057 compound was not as efficient at inhibiting the replication of flaviviruses as for other RNA+ viruses, with a modest antiviral effect demonstrated for WNV and a higher efficacy on JEV. This antiviral presents however potentials for applications in equine veterinary medicine because it efficiently inhibited equine herpes virus-1 and equine arteritis virus in vitro, as clearly shown by other collaborators
Machado, Daiane Cristina. "Sequenciamento do genoma completo do vírus Culex flavivirus (Flaviviridae) isolado no Brasil /." São José do Rio Preto, 2016. http://hdl.handle.net/11449/154714.
Full textBanca: Marilia de Freitas Calmon
Banca: Aripuanã Sakurada Aranha Watanabe
Resumo: No Brasil, a presença de ecossistemas com uma grande riqueza e diversidade de animais e cidades grandes e densamente povoadas oferece condições para a ocorrência de diversas arboviroses. Vários arbovírus transmitidos por mosquitos do gênero Culex pertencem ao gênero Flavivirus. Vírus desse gênero são conhecidos por causar doenças em humanos e animais, no entanto, flavivírus que não infectam ou causam doença em vertebrados, replicando somente em artrópodes têm sido descritos. O vírus Culex flavivirus é um exemplo. Ele foi isolado de espécies de mosquitos do gênero Culex na América do Norte, América Central, América do Sul, África e Ásia. Apesar dos estudos realizados em outras partes do mundo, no Brasil há ainda pouca informação sobre esse vírus. Nesse trabalho, realizamos o seqüenciamento do genoma completo do vírus Culex flavivirus (CxFV) isolado de mosquitos Culex de São José do Rio Preto (SP), por meio das técnicas de RT-PCR e seqüenciamento nucleotídico. O genoma viral do isolado CxFV_RPBR07_2007, o qual foi obtido no presente estudo apresentou 10.706 nucleotídeos com uma ORF de 10.092 nucleotídeos (3.364 aminoácidos) flanqueada por uma 5'UTR de 32 nucleotídeos e uma 3'UTR de 582 nucleotídeos. Análises filogenéticas revelaram que o CxFV_RPBR07_2007 agrupa-se com outros flavivírus de insetos, como o Cell fusing agent virus (CFAV) e o Kamiti River virus (KRV), e relaciona-se intimamente com isolados de CxFV do México (América Latina) e de Uganda (África); mantendo relação também com isolados dos Estados Unidos (América do Norte) e do Japão (Ásia). Esses agrupamentos foram também observados em outros estudos filogenéticos
Abstract: In Brazil, the presence of ecosystems with a wealth and diversity of animals, and cities large and densely populated offers conditions for the occurrence of many arboviruses. Several arboviruses transmitted by mosquitoes of the genus Culex belong to the genus Flavivirus. Viruses of this genus are known to cause disease in humans and animals, however, flaviviruses do not infect or cause disease in vertebrates, replicating only in arthropods have been described. Culex flavivirus virus is an example. He was isolated from species of mosquitoes of the genus Culex in North America, Central America, South America, Africa and Asia. Although studies conducted in other parts of the world, in Brazil there is still little information about this virus. In this work we performed the sequencing of the complete genome of Culex flavivirus virus (CxFV) isolated from Culex mosquitoes in São José do Rio Preto (SP) using the techniques of RT-PCR and nucleotide sequencing. The viral genome of the isolated (CxFV_RPBR07_2007) obtained in the present study presented 10.706 nucleotides with an ORF of 10.092 nucleotides (3.364 amino acids) flanked by a 5'UTR of 32 nucleotides and a 3'UTR of 582 nucleotides. Phylogenetic analyzes revealed that the CxFV_RPBR07_2007 groups with other insect flaviviruses such as the Cell fusing agent virus (CFAV) and Kamiti River virus (KRV), and is closely related to CxFV isolates from Mexico (Latin America) and Uganda (Africa); also maintaining relationship with isolates from the United States of America (North America) and Japan (Asia). These groupings were also observed in other phylogenetic studies
Mestre
Machado, Daiane Cristina [UNESP]. "Sequenciamento do genoma completo do vírus Culex flavivirus (Flaviviridae) isolado no Brasil." Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/154714.
Full textCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
No Brasil, a presença de ecossistemas com uma grande riqueza e diversidade de animais e cidades grandes e densamente povoadas oferece condições para a ocorrência de diversas arboviroses. Vários arbovírus transmitidos por mosquitos do gênero Culex pertencem ao gênero Flavivirus. Vírus desse gênero são conhecidos por causar doenças em humanos e animais, no entanto, flavivírus que não infectam ou causam doença em vertebrados, replicando somente em artrópodes têm sido descritos. O vírus Culex flavivirus é um exemplo. Ele foi isolado de espécies de mosquitos do gênero Culex na América do Norte, América Central, América do Sul, África e Ásia. Apesar dos estudos realizados em outras partes do mundo, no Brasil há ainda pouca informação sobre esse vírus. Nesse trabalho, realizamos o seqüenciamento do genoma completo do vírus Culex flavivirus (CxFV) isolado de mosquitos Culex de São José do Rio Preto (SP), por meio das técnicas de RT-PCR e seqüenciamento nucleotídico. O genoma viral do isolado CxFV_RPBR07_2007, o qual foi obtido no presente estudo apresentou 10.706 nucleotídeos com uma ORF de 10.092 nucleotídeos (3.364 aminoácidos) flanqueada por uma 5'UTR de 32 nucleotídeos e uma 3'UTR de 582 nucleotídeos. Análises filogenéticas revelaram que o CxFV_RPBR07_2007 agrupa-se com outros flavivírus de insetos, como o Cell fusing agent virus (CFAV) e o Kamiti River virus (KRV), e relaciona-se intimamente com isolados de CxFV do México (América Latina) e de Uganda (África); mantendo relação também com isolados dos Estados Unidos (América do Norte) e do Japão (Ásia). Esses agrupamentos foram também observados em outros estudos filogenéticos
In Brazil, the presence of ecosystems with a wealth and diversity of animals, and cities large and densely populated offers conditions for the occurrence of many arboviruses. Several arboviruses transmitted by mosquitoes of the genus Culex belong to the genus Flavivirus. Viruses of this genus are known to cause disease in humans and animals, however, flaviviruses do not infect or cause disease in vertebrates, replicating only in arthropods have been described. Culex flavivirus virus is an example. He was isolated from species of mosquitoes of the genus Culex in North America, Central America, South America, Africa and Asia. Although studies conducted in other parts of the world, in Brazil there is still little information about this virus. In this work we performed the sequencing of the complete genome of Culex flavivirus virus (CxFV) isolated from Culex mosquitoes in São José do Rio Preto (SP) using the techniques of RT-PCR and nucleotide sequencing. The viral genome of the isolated (CxFV_RPBR07_2007) obtained in the present study presented 10.706 nucleotides with an ORF of 10.092 nucleotides (3.364 amino acids) flanked by a 5'UTR of 32 nucleotides and a 3'UTR of 582 nucleotides. Phylogenetic analyzes revealed that the CxFV_RPBR07_2007 groups with other insect flaviviruses such as the Cell fusing agent virus (CFAV) and Kamiti River virus (KRV), and is closely related to CxFV isolates from Mexico (Latin America) and Uganda (Africa); also maintaining relationship with isolates from the United States of America (North America) and Japan (Asia). These groupings were also observed in other phylogenetic studies
Fernandes, Lícia Natal. "Identificação de infecção por Flavivirus em mosquitos (Diptera: Culicidae) coletados em áreas verdes da cidade de São Paulo." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/99/99131/tde-03082015-102328/.
Full textIntroduction: Among the arboviruses transmitted in Brazil, Flavivirus are noteworthy once they cause the largest number of infections and diseases in humans and also because they can cause serious illnesses. In the city of São Paulo there are green spaces, represented by city parks in which lakes, birds and mammals are found. The population visits those places, which can also be a refuge for mosquitoes that infect the urban area. Some studies reveal the occurrence of mosquitoes species known to be vectors of Flavivirus in this city, what can contribute to the emergence of cases and transmission of diseases caused by this kind of virus. However, the presence of Flavivirus infecting those arthropods is not known. Objective: To Identify infection by Flavivirus in mosquitoes (Diptera: Culicidae) collected in São Paulo\'s city parks. Method: Seven city parks located in different places of the city were selected for the study. Monthly mosquito collections were carried out in each park from March 2011 to February 2012. The traps employed were aspirator, Shannon and CDC-CO2. The mosquitoes were transported to the laboratory on dry ice. Identification was performed in a chill table. Up to 10 non-engorged females were pooled according to specie, date and place of collection. Engorged females were stored individually. Nucleic acids were extracted and submitted to real time RT-PCR that amplifies a 200pb fragment of NS5 gene of Flavivirus. Positive samples were sequenced and phylogenetic analyses were performed. Results: Eleven genus of Culicidae were found among the 5,213 non engorged females (818 pools) and the 778 engorged females. Culex and Aedes were the most frequent collected genus. Nineteen non engorged female pools had positive results for the presence of Flavivirus RNA. Phylogenetic analyses showed the RNA found was related to Aedes flavivirus (AEFV) in two pools of Aedes and to Culex flavivirus (CxFV) in the other pools, all of them consisting of Culex. Conclusion: CxFV and AEFV are present in mosquitoes Culex and Aedes, respectively, collected in São Paulo\'s city parks. Flavivirus of medical importance were not detected. Although, once there are species of mosquitoes that can act as vectors of pathogenic Flavivirus and vertebrate hosts, which are required for the transmission cycle of those virus, surveillance is recommended in the studied areas.
Pastorino, Boris. "Etude du complexe protéasique des flavivirus et des alphavirus : caractérisations enzymatiques et recherche de cibles cellulaires." Aix-Marseille 2, 2008. http://www.theses.fr/2008AIX20671.
Full textRechoum, Yassine. "Détection de séquences d'ARN du VHC dans des extraits de moustiques du genre Aedes : étude cinétique après infections expérimentales." Grenoble 1, 2009. http://www.theses.fr/2009GRE10205.
Full textLn order to explore the ability of mosquitoes to replicate HCV, we conducted a series of experimental infections caspius on Aedes, Aedes vexans and Culex pipiens wild and farmed. After collection of mosquitoes, the females were fed a blood meal viremic (HCV 1b positive). The mosquitoes were th en maintained in breeding for several days. After development of detection conditions, we were able to demonstrate HCV repli cation in the mosquito Aedes vexans. Ln the first experimental infection performed on Ae. Vexans, we detected HC' RNA in - 50% of mosquitoes 21st days post-infection (JPI), PCR end point. The second infection experiment, conducted on Iwo types of mosquitoes: Aedes SP, and Culex pipiens, has allowed us to: (i) confirmation by qRT-PCR results of the first experience with an infection rate of - 33%, (ii) demonstrate that only the mosquito Aedes contained RNA HCV, the Culex mosquitoes were ail negative, (iii) show that the RNA detected was good of replication, the extent of adaptive mutations were identified in the sequence of the RdRp (RNA polymerasi RNA dependent), with specificity for the genus Aedes, since ail Culex mosquitoes at 21 YPI were HCV RNA-negative. Another way to distinguish RNA from the replication of RNA remaining was to show the existence of a release within the mosquito. To do this, we conducted a third experiment infections (gender Ae. Caspius and Ae. Vexans), over a'period of 15 days and analyzed the presence of HCV RNA in distinct heads and bodies. Ln conducting samples at different times after infection (0, 4, 8 and 15 days), we managed to obtain a kinetic infection separately in heads and bodies, detection performed by WTA (Whole transcriptomics Amplification) followed by qPCR. On the day of infection (DO), the infection rate in the heads and bodies of mosquitoes was 9. 1 % and 100% respectively, the rate rose to 57. 1% and 85. 7% respectively J15 negativity after eight days after infection. On the other hand, we have identified mutations in th adaptation of the IRES sequence of mosquito D15 compared to those on day O. It is interesting to note that mosquito-positive HCV RNA ail belonged to the species vexans, showing that replication is species specific. Different regions of the HCV genome, then, were amplified. Finally, we made use of mosquito breeding. Infection of this strain has also shown, using different approaches to detection (qRT-PCR, qPCR-WTA, including HCV-GA), only 30 JPI, HCV RNA was present in - 33% heads and - 66% of the body, while infection rates were JO - 28% - 71 % in the head and body respectively. The results were based on sequencing performed on the amplified region! of the HCV genome. Ali these results show that HCV is able to replicate in mosquitoes of the genus Ae. Vexans, suggesting that HCV, likt other flaviviruses, can alternate belween Iwo hosts (primates and mosquitoes) and has lost its potential for replication in the mosquito ove time
Cespedes, Graziely Ferreira [UNESP]. "Sínteses e estudos dos diferentes peptídeos de fusão dos flavivirus causadores da dengue." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/108473.
Full textO vírus da dengue afeta milhões de pessoas a cada ano no mundo todo. O processo de infecção viral pela via endossomal é intermediada pela sequência 98 a 112 (DRGWGNGCGLFGKGG), conhecido como peptídeo de fusão, este segmento faz parte da glicoproteína E, localizado no envelope do vírus. Todos os flavivirus, incluindo os quatro sorotipos da dengue, apresentam esta sequência em regiões próximas, além de apresentarem alta identidade. Apesar de intensas pesquisas e o aumento da incidência de casos da dengue, não existem drogas antivirais específicas, até este momento, para o combate desta doença. Deste modo, a compreensão da interação do vírus com as células hospedeiras é importante na busca de novos fármacos. Neste sentido, este trabalho visou entender melhor o modo de ação do peptídeo de fusão da dengue e a importância de suas regiões laterais. O objetivo deste projeto teve por finalidade avaliar as contribuições das regiões laterais ao peptídeo de fusão, isto é, 88-97 e 113-123, em sua atividade, para os quatro sorotipos da dengue. A obtenção dos peptídeos foi realizada por meio da síntese em fase sólida. Os modelos de membrana utilizados foram micelas zwitteriônicas (LPC) e vesículas (PC ovo e POPG). Sabendo-se que a exposição desta sequência e, consequente, fusão da membrana é dependente do pH do meio, os estudos foram realizados em pHs 5,5 e 7,1. Nestes estudos, foram utilizadas as técnicas de Transferência de Energia de Ressonância de Föster (FRET), Dicroísmo Circular, Fluorescência, Monocamadas de Langmuir e BAM. O aminoácido triptofano foi usado como sonda para analisar a profundidade da inserção em miméticos de membrana. Os resultados mostraram que a SPFS foi útil, obtendo os materiais desejados. Avaliando a habilidade fusogênica dos 14 peptídeos estudados, observamos que cada sorotipo apresenta atividade diferente um do outro, sendo que os peptídeos do sorotipo 2 foram os que...
Dengue virus affects millions of people worldwide every year. The process of viral infection via endosomal is mediated by the sequence 98-112 (DRGWGNGCGLFGKGG), known as the fusion peptide. This segment is part of the glycoprotein envelope of the virus. All flavivirus, including all four dengue serotypes, contain this fusion sequence and all serotypes present high sequence identity. Although intense researches, the dengue cases have increased and, up to date, there are no specific antiviral drugs to combat this disease. Thus, understanding the virus interaction with host cells is essential for the search and development of new drugs against the dengue virus. Therefore, this study craved a better understanding of the mode of action of the dengue fusion peptide sequence and the importance of its lateral regions. This project aimed to assess the contributions of the lateral regions of the fusion peptide (88-97 and 113-123 sequences) on its activity, for the four dengue serotypes. The synthesis of peptides was performed by solid phase peptide synthesis (SPPS). The membrane models used were zwitterionic micelles (LPC) and vesicles (egg PC and POPG). Since the exposure of this sequence and the resulting membrane fusion is dependent on pH, studies were performed in pH 5.5 and 7.1. In these studies, the techniques of Resonance Energy Transfer Föster (FRET), circular dichroism, fluorescence, Langmuir monolayers and BAM (Brewster angle microscopy) were used. The amino acid and natural fluorophore tryptophan was used as a probe to analyze the insertion depth of the fusion peptide in the membrane mimetic by fluorescence. The results showed that the SPPS was feasible, obtaining the desired materials. Assessing the fusogenic ability of 14 peptides studied, the data indicated that each serotype has different activity and the serotype 2 peptides presented the major interaction. The studies of interaction peptide/membrane mimetic indicated...
Pettersson, John H. O. "The Origin of the Genus Flavivirus and the Ecology of Tick-Borne Pathogens." Doctoral thesis, Uppsala universitet, Systematisk biologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-211090.
Full textMather, Stuart Thomas. "Development of pseudotyped virus assays for the serological study of Japanese encephalitis flavivirus." Thesis, University of Kent, 2017. https://kar.kent.ac.uk/62936/.
Full textEvangelista, Villavicencio Julio Antonio. "Caracterización de un nuevo flavivirus aislado de Culex (melanoconion) ocossa de Iquitos, Perú." Master's thesis, Universidad Nacional Mayor de San Marcos, 2016. https://hdl.handle.net/20.500.12672/4885.
Full textTesis
Cespedes, Graziely Ferreira. "Sínteses e estudos dos diferentes peptídeos de fusão dos flavivirus causadores da dengue /." Araraquara, 2013. http://hdl.handle.net/11449/108473.
Full textBanca: Reinaldo Marchetto
Banca: Saulo Santesso Garrido
Banca: Pietro Ciancaglini
Banca: Luciana Malavolta Quaglio
Resumo: O vírus da dengue afeta milhões de pessoas a cada ano no mundo todo. O processo de infecção viral pela via endossomal é intermediada pela sequência 98 a 112 (DRGWGNGCGLFGKGG), conhecido como peptídeo de fusão, este segmento faz parte da glicoproteína E, localizado no envelope do vírus. Todos os flavivirus, incluindo os quatro sorotipos da dengue, apresentam esta sequência em regiões próximas, além de apresentarem alta identidade. Apesar de intensas pesquisas e o aumento da incidência de casos da dengue, não existem drogas antivirais específicas, até este momento, para o combate desta doença. Deste modo, a compreensão da interação do vírus com as células hospedeiras é importante na busca de novos fármacos. Neste sentido, este trabalho visou entender melhor o modo de ação do peptídeo de fusão da dengue e a importância de suas regiões laterais. O objetivo deste projeto teve por finalidade avaliar as contribuições das regiões laterais ao peptídeo de fusão, isto é, 88-97 e 113-123, em sua atividade, para os quatro sorotipos da dengue. A obtenção dos peptídeos foi realizada por meio da síntese em fase sólida. Os modelos de membrana utilizados foram micelas zwitteriônicas (LPC) e vesículas (PC ovo e POPG). Sabendo-se que a exposição desta sequência e, consequente, fusão da membrana é dependente do pH do meio, os estudos foram realizados em pHs 5,5 e 7,1. Nestes estudos, foram utilizadas as técnicas de Transferência de Energia de Ressonância de Föster (FRET), Dicroísmo Circular, Fluorescência, Monocamadas de Langmuir e BAM. O aminoácido triptofano foi usado como sonda para analisar a profundidade da inserção em miméticos de membrana. Os resultados mostraram que a SPFS foi útil, obtendo os materiais desejados. Avaliando a habilidade fusogênica dos 14 peptídeos estudados, observamos que cada sorotipo apresenta atividade diferente um do outro, sendo que os peptídeos do sorotipo 2 foram os que...
Abstract: Dengue virus affects millions of people worldwide every year. The process of viral infection via endosomal is mediated by the sequence 98-112 (DRGWGNGCGLFGKGG), known as the fusion peptide. This segment is part of the glycoprotein envelope of the virus. All flavivirus, including all four dengue serotypes, contain this fusion sequence and all serotypes present high sequence identity. Although intense researches, the dengue cases have increased and, up to date, there are no specific antiviral drugs to combat this disease. Thus, understanding the virus interaction with host cells is essential for the search and development of new drugs against the dengue virus. Therefore, this study craved a better understanding of the mode of action of the dengue fusion peptide sequence and the importance of its lateral regions. This project aimed to assess the contributions of the lateral regions of the fusion peptide (88-97 and 113-123 sequences) on its activity, for the four dengue serotypes. The synthesis of peptides was performed by solid phase peptide synthesis (SPPS). The membrane models used were zwitterionic micelles (LPC) and vesicles (egg PC and POPG). Since the exposure of this sequence and the resulting membrane fusion is dependent on pH, studies were performed in pH 5.5 and 7.1. In these studies, the techniques of Resonance Energy Transfer Föster (FRET), circular dichroism, fluorescence, Langmuir monolayers and BAM (Brewster angle microscopy) were used. The amino acid and natural fluorophore tryptophan was used as a probe to analyze the insertion depth of the fusion peptide in the membrane mimetic by fluorescence. The results showed that the SPPS was feasible, obtaining the desired materials. Assessing the fusogenic ability of 14 peptides studied, the data indicated that each serotype has different activity and the serotype 2 peptides presented the major interaction. The studies of interaction peptide/membrane mimetic indicated...
Doutor
Serra, Otacília Pereira. "Arbovírus dos gêneros Flavivirus e Alphavirus em culicídeos capturados em Cuiabá, Mato Grosso." Universidade Federal de Mato Grosso, 2015. http://ri.ufmt.br/handle/1/694.
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CAPES
FAPEMAT
Arbovírus são transmitidos por artrópodes hematófagos, representando um problema de saúde pública em áreas tropicais. O objetivo deste estudo foi investigar a diversidade de espécies de culicídeos e sua frequência de infecção por Alphavirus e Flavivirus em Cuiabá, MT. Foram realizadas capturas com aspirador de Nasci e puçá entre janeiro e abril de 2013 em três locais de 200 setores censitários, definidos aleatoriamente. Os culicídeos foram identificados com chave dicotômica de Forattini, alocados em pools (1-20 mosquitos) segundo sexo, espécie, data, local de coleta e armazenados a -80˚C. Pools de fêmeas foram submetidos à extração de RNA e DNA total, à multiplex semi-nested-RT-PCR para cinco alphavírus e 11 flavivírus e Nested- PCR para identificação de Culex (Cx.) quinquefasciatus. Amostras positivas para SLEV, DENV-1, -4 e MAYV foram submetidas a single RT-PCR e sequenciamento nucleotídico. Pools positivos para o MAYV foram inoculados em células Vero e submetidos a RT-PCR para o gene de envelope E1 dos alphavirus. Pools positivos para flavivirus foram inoculados em células C6/36 (Flavivirus). Calculou-se a taxa de infecção mínima (MIR). Foram capturados 11.090 mosquitos, 4.556 fêmeas de 14 espécies, perfazendo 610 pools. Foram analisados 171 pools de Aedes (Ae.) aegypti; 1 Ae. albopictus; 1 Aedes sp.; 5 Cx. bidens/interfor; 1 Cx. spinosus; 403 Cx. quinquefasciatus; 1 Galindomyia sp; 6 Limatus sp; 2 Mansonia wilsoni; 5 Psorophora (Ps.) sp; 1 Ps. ciliata; 11 Ps. varipes/albigenu; 1 Sabethes chloropterus e 1 Uranotaenia sp. Encontrou-se 1/171 (MIR=0,92) pool de Ae. aegypti positivo para DENV-1; 1/403 (MIR= 0,2) Cx. quinquefasciatus para SLEV genótipo V-A, 12/403 (MIR=3,5) de Cx. quinquefasciatus, 4/171 (MIR=3,67) de Ae. aegypti para MAYV; destes, cinco pools apresentaram co-infecção com DENV-4. Um produto de 1,3 kb obtido com o protocolo para o gene de envelope de três pools positivos para o MAYV resultou em sequências nucleotidicas inespecíficas. O MAYV foi isolado de dois pools contendo duas fêmeas não ingurgitadas de Ae. aegypti (#958) e duas de Cx. quinquefasciatus (#489). Positividade para DENV-4 foi identificada em 58/171 (MIR=53,35) Ae. aegytpi, 105/403 (MIR=30,65) Cx. quinquefasciatus, 2/5 (MIR=400) Psorophora sp, 2/11 (MIR=142,85) Ps. varipes/albigenu, 1/1 (MIR= 1000) Sabethes chloropterus, 2/5 (MIR=285.7) Cx. bidens/interfor e 1/1 (MIR=1000) Aedes sp. O DENV-4 foi isolado de dois pools contendo três (#329) e 16 (#806) fêmeas de Cx. quinquefasciatus não ingurgitadas. O SLEV, MAYV e os sorotipos do DENV foram identificados em pacientes com suspeita de dengue na cidade de Cuiabá em estudos prévios do Laboratório de Virologia. Experimentalmente, Culex e Aedes spp. são vetores competentes do MAYV. A identificação do vírus em fêmeas não ingurgitadas sugere que estas espécies podem estar envolvidas no ciclo urbano do MAYV em Cuiabá. Dentre os sorotipos do DENV, somente o DENV-1 e o DENV-4 foram identificados em culicídeos. O DENV-4 tem produzido importantes epidemias em MT desde 2012. A positividade para DENV-4 em diferentes espécies de culicídeos pode ser decorrente de infecção natural ou da hematofagia em humanos, pois muitos destes pools apresentavam fêmeas ingurgitadas. Cuiabá possui ecossistema favorável para a ocorrência de arboviroses e proliferação de vetores. Estudos envolvendo vigilância entomológica e virológica são importantes para estimar a situação epidemiológica dos arbovírus no estado.
Arbovirus are transmitted by hematophagous arthropods, posing a public health issue in tropical areas. The aim of this study was to investigate the diversity of culicidae and their frequency of infection by arboviruses from Alphavirus and Flavivirus genus in Cuiabá, MT. To achieve that, culicids were captured with Nasci aspirators and hand net between January and April 2013 in three locations of 200 censitary sectors randomly defined. The specimens were identified using the Forattini dichotomy key, allocated in pools (1-20 mosquitoes), according to sex, species, day and place of capture, and stored at -80˚C. Female pools were subjected to total RNA and DNA extraction and to multiplex semi-nested-RT-PCR for five alphaviruses and 11 flaviviruses and Nested-PCR for Culex (Cx.) quinquefasciatus identification. The pools positive for SLEV, DENV-1, -4 and MAYV were subjected to single RT-PCR and nucleotide sequencing. MAYVpositive pools were inoculated in Vero cells and subjected to RT-PCR for the E1 envelope gene of alphaviruses. Pools positive for flaviviruses were inoculated in C6/36 cells. The minimum infection rate (MIR) was calculated. 11,090 mosquitoes were captured, 4,556 females belonging to 14 species, comprising 610 pools, 171 pools of Aedes (Ae.) aegypti specimens; 1 Ae. albopictus; 1 Aedes sp.; 5 Cx. bidens/interfor; 1 Cx. spinosus; 403 Cx. quinquefasciatus; 1 Galindomyia sp.; 6 Limatus sp.; 2 Mansonia wilsoni; 5 Psorophora sp.; 1 Ps. ciliata; 11 Ps. varipes/albigenu; 1 Sabethes chloropterus e 1 Uranotaenia sp. Among them, 1/171 (MIR=0.92) Ae. aegypti pool was positive for DENV-1 and 1/403 (MIR=0.3) Cx. quinquefasciatus for SLEV genotype V-A. For MAYV, 12/403 (MIR=3.5) Cx. quinquefasciatus, 4/171 (MIR=3.67) Ae. aegypti were positive, five of them were also infected by DENV-4. A DNA product with 1.3 kb obtained from three pools positive for MAYV with the protocol for the envelope gene resulted in unspecific nucleotide sequences. MAYV was isolated from two pools, both containing two non-engorged females of Ae. aegypti (#958) and Cx. quinquefasciatus (#489). DENV-4 was detected in 58/171 (MIR=53.35) Ae. aegytpi, 105/403 (MIR=30,65) Cx. quinquefasciatus, 2/5 (MIR=400) Psorophora sp., 2/11 (MIR=142.85) Ps. varipes/albigenu, 1/1 (MIR= 1000) Sabethes chloropterus, 2/5 (MIR=285.7) Cx. bidens/interfor and 1/1 (MIR=1000) Aedes sp. DENV-4 was isolated from two pools containing three (#329) and 16 (#806) non-engorged females of Cx. quinquefasciatus. The SLEV, MAYV and the four DENV serotypes were identified in patients suspected of harboring dengue infection in Cuiabá in previous studies of the Virology Laboratory. Experimentally, Culex and Aedes spp. are competent vectors for MAYV. The identification of the virus in nonengorged females suggests these species may be involved in the urban cycle of MAYV in Cuiabá. Among the DENV serotypes, only DENV-1 and DENV-4 were identified in culicids captured in the city. DENV-4 has been responsible for major outbreaks in MT since 2012. The identification of DENV-4 in several mosquito species might be resultant either from natural infection or hematophagy in humans, since several of these pools presented engorged females. Cuiabá presents a favorable ecosystem for the occurrence of arboviruses and vector proliferation. Studies involving entomological and virological surveillance are important to estimate the epidemiological situation of arboviruses in the state.
Desole, Giovanna. "Comparative analysis of Zika virus and other Flavivirus infection in human neural cells." Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3424985.
Full textPresupposti dello studio: Zika virus (ZIKV), West Nile virus (WNV), dengue virus (DENV) e Usutu virus (USUV) sono trasmessi da zanzare ed appartengono al genere Flavivirus della famiglia Flaviviridae. L’infezione da ZIKV è associata a microcefalia fetale e sindrome di Guillan-Barrè; WNV può causare una grave sindrome neuroinvasiva nell’anziano e nei soggetti immunocompromessi; l’infezione da DENV raramente si associa a complicazioni neurologiche; USUV può causare una sindrome neuroinvasiva fatale in diverse specie di uccelli, è stato dimostrato che può infettare pure l’uomo, ma la sua patogenicità resta ancora da chiarire. Scopo: Alla luce della recente epidemia di ZIKV in America e di una probabile associazione tra l’infezione da ZIKV e lo sviluppo di microcefalia fetale, lo scopo di questo studio è stato confrontare l’infezione da ZIKV sulle cellule neurali umane con l’infezione da WNV, DENV e USUV. A tal fine, la cinetica di replicazione, l’effetto citopatico e l’immunità innata indotta dall’infezione virale sono state analizzate in cellule staminali pluripotenti indotte (hiPSCs), cellule staminali neurali derivate da iPSCs e neuroni. Materiali e metodi: Le NSCs ed i neuroni sono stati differenziati da hiPSCs. I diversi tipi cellulari sono stati infettati con l’isolato di ZIKV lignaggio asiatico (KU853013), WNV lignaggio 2 (KF179640), DENV sierotipo 2 e USUV lignaggio 1 europeo (AY453411). La carica virale è stata valutata a diversi tempi dall’infezione mediante qRT-PCR e TCID50, il livello di espressione dei geni coinvolti nell’immunità innata è stato analizzato mediante qRT-PCR e l’espressione dei markers di differenziamento cellulare mediante IF e qRT-PCR, la sopravvivenza cellulare e l’apoptosi mediante il saggio MTT e analisi dell’attivazione di caspasi-3. L’impatto dell’infezione da ZIKV sull’embriogenesi e la neurogenesi è stato valutato infettando le hiPSCs e le NSCs durante il differenziamento neurale e durante la formazione dei corpi embrioidi. Risultati: ZIKV era in grado di infettare e replicare efficientemente nelle NSCs, nei neuroni e nelle hiPSCs, causando un tipico effetto citopatico e morte cellulare per apoptosi. L’infezione ha indotto un significativo aumento dell’espressione dei geni dell’immunità innata, in particolare dei geni MDA5 (the cellular pattern recognition receptor (PRR) IFH1 gene), IFIT1 (IFN-induced protein with tetratricopeptide repeats 1) e IFIT2. I corpi embrioidi sono stati distrutti dal virus e le hiPSCs e le NSCs infettate sono morte prima di completare il differenziamento neurale. L’efficienza di replicazione di ZIKV nelle NSCs era maggiore rispetto a quella di DENV-2 e USUV, ma minore rispetto al WNV. Infatti, WNV replicava in modo più efficiente, induceva una maggiore morte cellulare e stimolava una più elevata risposta antivirale rispetto a ZIKV nei diversi tipi cellulari. Conclusione: ZIKV infetta e replica nelle NSCs, inducendo morte cellulare e impedendo lo sviluppo neurale, ma in modo meno efficiente rispetto al WNV. E’ probabile quindi che l’infezione di altri tipi cellulari sia determinante per il danno al sistema nervoso fetale indotto in modo specifico da ZIKV.
Orico, Lilian Dias. "Pesquisa de infecções por Flavivirus sp. em aves silvestres provenientes das áreas verdes do município de São Paulo." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/6/6132/tde-11112013-142955/.
Full textINTRODUCTION: In big cities, as São Paulo, the little percentage of existing forests is represented by the municipal parks. These áreas, besides acting as entertainment environments to the users, promote a huge biodiversity, including mosquitoes, birds and mammals. These species interaction promotes Flavivirus circulation, viruses responsible for important human diseases. The avian species are important reservoirs for these viruses, specially the migrating birds that can fly for long distances, carrying these viruses to several areas. In some parks, the arrival of migrating birds from the North Hemisphere is documented, fact that can support some viruses dispersion, for example, the West Nile Vírus, considering that in these areas potencial vector for this virus can be found. OBJECTIVES: detect Flavivirus infection in birds captured in municipal parks of São Paulo city. METHODS: from March, 2012 to January, 2013, oropharyngeal and cloacal swabs, and blood samples were collected from birds captured in mist-net webs located in two municipal areas: Anhanguera Park and Castanheiras Farm/APA Bororé Colônia. The birds were ringed and released after samples collection. The real time RT-PCR was performed, using generic primers which amplify NS5 gene fragment. Positive samples were forwarded to sequence analysis. RESULTS: a total of 231 birds were capture, in which the majority belongs to Passeriforms order. Of 463 samples collected, all samples were negative for the viral RNA presence. DISCUSSION: when talking about Flaviviruses, the passeriforms are considered the most competent reservoirs in the transmission cycle, because they can achieve great viremia levels. Some passeriforms species, endemic in São Paulo city, were identified as Rocio and Ilhéus viruses carriers in previous studies. The negativity is expected, once the Real Time RT-PCR, although highly sensitive, depends on the viremia duration, which is short in avian species. CONCLUSION: the public parks are areas which encloses birds, mosquitoes and the human being, for the environmental and entertainment role they play. This fact classifies these parks as areas with great potencial of Flavivirus transmission, ressalting the great importance to continue this study, increasing the number of areas, to detect the circulating Flavivirus and to perform surveillance for viruses which can cause public health problems
Bouvet, Mickaël. "Etude d'enzymes de modification d'ARN impliquées dans la réplication des flavivirus et des coronavirus." Thesis, Aix-Marseille 2, 2011. http://www.theses.fr/2011AIX20714.
Full textThis work focused on enzymatic activities of two RNA virus genera, Flavivirus and Coronavirus.We first studied the mRNA cap synthesis machinery of these viruses. Indeed, as they replicate in the cytoplasm of the infected cell, these viruses encode their own mRNA cap-forming enzymes. The canonical mechanism of cap synthesis uses four enzymatic activities, a RNA 5’-triphosphatase, a guanylyltransferase and two methyltransferases.We tried to identify the guanylyltransferase activity involved in this process for flaviviruses and we developed enzymatic assays to characterize both guanylyltransferase and methyltransferase activities. We used the methyltransferase assay in order to test the inhibitor effect of molecules, selected by virtual screening, on the methyltransferase activities of the NS5 protein involved in the capping process.Concerning coronaviruses, we first focused on the methyltransferase activities of the nsp14 and nsp16 proteins. We have reconstituted the complete SARS-CoV mRNA cap methylation in vitro. We showed that mRNA cap methylation requires a third viral protein, nsp10, which acts as an essential trigger to complete RNA cap-1 formation. The obligate sequence of methylation events is initiated by nsp14, which first methylates capped RNA transcripts to generate cap-0 7MeGpppA-RNAs. The latter are then selectively 2′O-methylated by the 2′O-methyltransferase nsp16 in complex with its activator nsp10 to give rise to cap-1 7MeGpppA2′OMe-RNAs. Then, we took interest in the exoribonuclease activity of the nsp14 protein and found that this activity is also regulated by the same cofactor, the nsp10 protein. The interaction between the proteins is required to observe the stimulatory effect and it seems that the surface areas of nsp10 interacting with nsp14 and nsp16 overlap. The in vitro characterization of the nuclease activity of nsp14 is according with its potential implication in RNA proofreading mechanism
Rückert, Claudia. "Alphavirus and flavivirus infection of Ixodes tick cell lines : an insight into tick antiviral immunity." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/10063.
Full textYouseff, Brian. "The Role of Tumor Necrosis Factor Receptor-Associated Factor 6 in Tick-Borne Flavivirus Infection." University of Toledo Health Science Campus / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=mco155691388498993.
Full textBessaud, Maël. "Etude in vitro du complexe protéasique [NS2B/NS3] des flavivirus, cible potentielle de molécules antivirales." Aix-Marseille 2, 2005. http://theses.univ-amu.fr.lama.univ-amu.fr/2005AIX22027.pdf.
Full textElbahesh, Husni. "Functional Analysis of the Murine Oligoadenylate Synthetase 1b (Oas1b)." Digital Archive @ GSU, 2006. http://digitalarchive.gsu.edu/biology_theses/3.
Full textCrochu, Sandrine. "Caractérisation génétique de virus atypiques du lignage des Flavivirus et mise en évidence d'un nouveau mécanisme évolutif des cellules eucaryotes." Aix-Marseille 2, 2004. http://www.theses.fr/2004AIX20674.
Full textBrandler, Samantha. "Etude du mécanisme d'inhibition de la fusion des flavivirus par les anticorps et mise au point d'un candidat vaccin contre la dengue basé sur l'expression d'un antigène d'enveloppe par un vecteur dérivé du vaccin contre la rougeole." Aix-Marseille 1, 2008. http://theses.univ-amu.fr.lama.univ-amu.fr/2008AIX11003.pdf.
Full textDengue fever is a reemerging disease that threatens one third of the world's population, for which no vaccine is available. In this work, we evaluated a new vaccination strategy based on the expression of a combined dengue antigen by a vector derived from the pediatric live attenuated measles vaccine. Understanding the mechanisms of flavivirus neutralization by antibodies is essential for the design of innovative vaccine approaches against dengue. Therefore, as a first step, we studied the mechanism of inhibition of fusion by neutralizing antibodies directed against the three domains of the envelope protein (E). The Tick-borne encephalitis virus (TBEV) was used as a model in in vitro fusion tests, and coflottation assays with lipid membranes. The results showed that the neutralizing antibodies can interfere with the early or late stages of the fusion process. This study also shows that antibodies against domain III of the E protein can block both the viral entry and fusion. As a proof-of-concept of our vaccination strategy, we inserted into measles vector the domain III of the glycoprotein E of dengue virus (EDIII), which contains the putative receptor binding site and serotype-specific neutralizing epitopes. To strengthen its immunogenicity, EDIII was fused with the pro-apoptotic ectodomain of the membrane protein (ectoM) of VDEN-1. Tested in mice susceptible to measles, this vaccine candidate was immunogenic and able to induce long term serotype-specific neutralizing antibodies. The presence of the ectoM proved crucial for the immunogenicity of EDIII. Its adjuvant capacity correlated with its ability to mature dendritic cells and to enhance the secretion of proinflammatory and antiviral cytokines, as well as chemokines involved in the development of adaptive immunity. A tetravalent measles-dengue candidate was then generated in order to induce the same immunity against the 4 serotypes of dengue virus. This vaccination strategy combining measles and dengue might offer an affordable pediatric vaccine particularly attractive to immunize children both against measles and dengue fever in areas of the world where the two diseases co-exist
Brient-Litzler, Elodie. "Biocapteurs fluorescents autonomes dérivés d'ankryines artificielles et bioconjugués pour le diagnostic précoce d'infections flavivirales." Paris 6, 2009. http://www.theses.fr/2009PA066014.
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