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Ahlm, Clas. "Distribution of puumala virus in Sweden." Doctoral thesis, Umeå universitet, Infektionssjukdomar, 1997. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-140825.
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Puumala virus, belonging to the genus hantavirus, is the causative agent of nephropathia epidemica (NE), a relatively mild form of hemorrhagic fever with renal syndrome. Puumala virus occurs endemically in Central and Northern Europe and Western Russia. In Sweden, NE is reported from the northern and central parts but virtually not at all from the southern part of the country. The bank vole (Clethrionomys glareolus) is the main reservoir of Puumala virus and humans are infected by inhalation of aerosolized animal secreta. In northern Sweden, the density of the bank vole population varies cyclically in intervals of 3-4 years and the incidence of NE shows a covariation. The prevalence of serum antibodies to hantaviruses in northern Sweden was studied in a stratified and randomly selected adult population sample comprising 1538 subjects. As expected, the prevalence increased with age. There was no difference between men and women, which was unexpected based on a male:female ratio of > 2:1 in clinical reports. By use of an immunofiuorescent assay, a seroprevalence of 5.4% and by a newly developed enzyme-linked immunosorbent assay (ELISA) with recombinant Puumala virus nucleocapsid protein as antigen, a prevalence of 8.9% was recorded. This is about or more than ten times higher than what would be calculated from clinical reports. By use of the ELISA, an occupational risk of acquisition of Puumala virus infection was demonstrated. Serum samples from 910 farmers and 663 referent subjects living in various rural parts of Sweden were tested. Among farmers from the Puumala virus-endemic northern and central parts of the country, the seroprevalence (12.9%) was higher (p=0.01) than in referents (6.8%). In the southern part of Sweden, only 2/459 persons had antibodies. Only a limited number of children with NE had been previously reported. In a separate study, 32 children with Puumala virus infection were identified and the clinical picture of NE in children was found to be similar to that of adult cases. Variations in the prevalence of Puumala virus in the bank vole population within an endemic region are not well known. Here, a higher mean rodent density and a higher prevalence of Puumala virus-specific serum antibodies were recorded in the vicinity of households afflicted with NE than in rural control areas. The data indicated that the risk of exposure locally within an endemic region may vary widely and tentatively suggested that a threshold density of bank voles might be necessary to achieve before effective spread of Puumala virus within the rodent population may occur. There is no firm evidence of the occurrence of Puumala virus among wild living animals other than rodents. A study of Swedish moose, an animal which is ecologically well characterized, was performed. Convincing evidence of past Puumala virus infection was found in 5/260 moose originating from Puumala virus-endemic areas but in none of 167 animals from nonendemic areas. Based on the low seroprevalence recorded, moose seemed to serve as endstage hosts rather than being active parts of the enzootic circle of transmission. In conclusion, the present investigations confirmed that the exposure to Puumala virus is geographically well restricted in Sweden. Seroprevalence studies indicated that only a minor proportion of individuals infected with Puumala virus are clinically reported, with a bias in favour of men. NE was confirmed to occur in children, with a clinical picture similar to that of adults. An occupational risk was defined for acquisition of Puumala virus infection. Studies in rodents suggested that there may be wide local variations within a limited area in the risk of exposure to Puumala virus. The studies validated the usefulness of a newly developed ELISA based on recombinant nucleocapsid peptides of hantaviruses and finally, methodological progress was reached when Puumala virus was, for the first time, successfully isolated from a Scandinavian patient.Diss. (sammanfattning) Umeå : Umeå universitet, 1998
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Caioni, Massimo. "Epstein-Barr virus subtype distribution in angioimmunoblastic lymphadenopathy /." [S.l : s.n.], 1994. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
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LaVenture, George M. "Software and the virus threat : providing authenticity in distribution." Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/28547.
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Van, Eijl Henriette Joselijn Leonie. "The distribution and topology of the vaccinia virus A36R protein." Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325640.
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Komurian-Pradel, Florence. "Variabilité génomique du virus HTLV-I (Human T-cell Leukemia Virus type I) en fonction de la géographie et des pathologies associées." Lyon 1, 1992. http://www.theses.fr/1992LYO1T001.
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Elom, Hilary, and Shimin Zheng. "The distribution of hepatitis c virus genotypes in US population. Data from NHANES 2006-2016." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/asrf/2018/schedule/116.
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Background: Unlike other non-hepatitis c viral infection, hepatitis c viral infection is a non-vaccine preventable disease. Thus, effective treatment is an important part in the prevention of complication of chronic hepatitis c infection. The viral genotype plays a significant role in the choice of treatment regimen.
Aim: the purpose of this study is to estimate the prevalence of hepatitis c viral infection and the distribution of viral genotype in the US population.
Methods: Diagnosis of Hepatitis C viral infection was made by assaying the blood specimen collected from the study participants using Ampiclor monitor (Roche Diagnostic System, Inc Branchburg NJ), and genotype determined from the NS5b region. The data is from NHANSE 2006-2016. SAS v 9.4 software was used to perform the analysis.
Results: Of the 356 participants (2006-2016) who tested positive to Hepatitis C virus-RNA, 205 persons had genotype 1a, 1b (n=66), other forms of genotype 1 (n=1), genotype 2(n=41), genotype 3 (n=30), genotype 4 (n=1), genotype 6(n=1), undetermined genotype (n=8). Based on weighted analysis of person infected with genotype 1, 2, 3; genotype 1 was highest across all ages and gender (78.2%). Of 271 participants infected with genotype 1, there were 5.09% Mexican Americans, 3.94% other Hispanics, 56.58% non-Hispanic whites, 28.74% non-Hispanic black, and 5.65% other races including multiracial population.
Subjects aged 50 years or above was 27.7% less likely being infected with HCV genotype 1 vs 2 and 3, compared with younger individuals (adjusted Odds Ratio (95% confidence interval) (aOR): 0.72 (0.72-0.73)). Non-Hispanic black were about 13 times (aOR: 13.1 (13.0-13.2)) as likely to be infected with genotype 1 vs 2 and 3 as non-Hispanic white.
Conclusion: Hepatitis C virus genotype 1 is predominant among those infected with hepatitis c virus in the US population. Improvement in therapy targeting genotype 1 is essential to reduce the burden and complication of chronic hepatitis C in the United States.
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McCormick, Benjamin Joseph James. "The determinants of the distribution of louping ill virus in Britain." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433369.
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Rauf, Abdul. "PERSISTENCE, DISTRIBUTION AND IMMUNOPATHOGENESIS OF INFECTIOUS BURSAL DISEASE VIRUS IN CHICKENS." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1299612513.
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Clerissi, Camille. "Diversité et distribution des Prasinovirus (Phycodnaviridae) : influence des facteurs environnementaux et mécanismes évolutifs." Paris 6, 2012. http://www.theses.fr/2012PA066371.
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Les picoeucaryotes contribuent fortement à la production primaire dans les océans, mais peu d'informations se rapportent à leurs virus. Ainsi, nous nous sommes intéressés à un système hôte-virus abondant et répandu, les Prasinovirus et leurs hôtes de la classe des Mamiellophyceae, pour décrire comment les facteurs environnementaux influencent la diversité et la distribution de ces virus, et quels sont les mécanismes évolutifs impliqués dans leur diversification. L'étude de la spécificité virale a montré qu'une souche ne pouvait pas infecter des genres différents, et que la majorité était spécifique d'une espèce. Il est donc possible de prédire les hôtes de séquences environnementales de Prasinovirus. Nous avons développé des amorces spécifiques pour amplifier l'ADN polymérase (PolB) et la protéine majeure de la capside (MCP) de virus environnementaux. La PolB a dévoilé une diversité plus homogène que la MCP, et a ainsi été utilisée pour étudier des milieux contrastés tels que des étangs méditerranéens et des sites ouverts de Méditerranée et de l'Océan Indien. Nous avons trouvé que leur distribution est corrélée à la géographie et à l'environnement, et que la disponibilité en phosphates pourrait contraindre les assemblages viraux. Enfin, leur diversité pourrait être favorisée par des gènes à évolution rapide impliqués dans la reconnaissance des hôtes, et par des échanges génétiques. En effet, la PolB peut contenir un gène égoïste appelé " intéine ", capable de transferts latéraux dans des allèles n'en contenant pas. Notre analyse suggère que des transferts entre virus sont courants et que des évènements de recombinaison sont possibles dans l'évolution des Prasinovirus
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Loveday, Rachel Ellen Leonard. "Influence of Seed Treatment on Tobacco Mosaic Virus Incidence in Tobacco Seedlings and Virus Distribution in Greenhouse Transplant Production." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/31396.
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Tobacco mosaic virus (TMV) is an economically important pathogen that has been studied for over one hundred years. Seedlings, seed coats, and nutrient solution were assayed for the presence of the virus and seed treatments were tested on seeds. Double antibody sandwich enzyme-linked immunosorbent assay (DAS ELISA) and biological local lesion assay data were collected. Seed coats from seed collected from TMV infected plants were always positive for TMV regardless of chemical treatment. Seed from infected source plants have lower germination than seed from healthy plants. Trisodium phosphate and hydrochloric acid treatments reduced virus infection of seedlings when grown under controlled conditions. Virus particles were serologically and biologically detected in both the leaves and roots of seedlings mechanically inoculated with TMV. Nutrient solution collected from 28 day old seedlings, 12 days post inoculation, tested positive for biologically active TMV by ELISA and infectivity assay. Infected water in float bed production could facilitate viral movement to all seedlings sharing nutrient solution. Seed transmission of TMV was shown to occur at a rate of 0.2%. This is in contrast to other research attempting to demonstrate seed transmission where visual symptoms on seedlings have been used to assess seed transmission.Master of Science
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Ligat, Julio S. "Pathology and distribution in the host of pea seed-borne mosaic virus." Title page, contents and summary only, 1993. http://web4.library.adelaide.edu.au/theses/09PH/09phl723.pdf.
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Includes bibliographical references (leaves 82-92). Five isolates of pea seed-borne mosaic virus were compared by host range and symptomatology on 16 pisum sativum cultivars lines, 21 lines of Lathyrus and Lens spp. and several indicator species
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Huneycutt, Brandon Scott. "Functional characterization and distribution of lymphokine secreting cells following influenza virus infection /." The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487683049375098.
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Aguilar-Luis, M. A., Miguel Angel Aguilar-Luis, Valle-Mendoza Juana del, Wilmer Silva-Caso, Tamara Gil-Ramirez, Saul Levy-Blitchtein, Jorge Bazán-Mayra, et al. "An emerging public health threat: Mayaro virus increases its distribution in Peru." Elsevier B.V, 2020. http://hdl.handle.net/10757/651732.
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Background: The infection caused by Mayaro virus (MAYV), which presents as an acute febrile illness, is considered a neglected tropical disease. The virus is an endemic and emerging pathogen in South America and the Caribbean, responsible for occasional and poorly characterized outbreaks. Currently there is limited information about its expansion and risk areas. Methods: A cross-sectional study was performed in 10 urban primary care health centers in the Cajamarca region of Peru from January to June 2017. A total of 359 patients with suspected febrile illness were assessed. RNA was extracted from serum samples, following which MAYV real-time reverse transcriptase PCR (RT-PCR) for the detection of the nsP1 gene was performed. Results: MAYV was detected in 11.1% (40/359) of samples after RT-PCR amplification and confirmatory DNA sequencing. Most infections were detected in the adult population aged 18–39 years (40%) and 40–59 years (32.5%). Headache was the most frequent symptom in patients with MAYV infection (77.5%), followed by fever (72.5%), myalgia (55.0%), and arthralgia (50.0%). During the study, most of the MAYV cases were seen in May (47.5%) and April (35.0%), corresponding to the dry season (months without rain). Conclusions: This study is novel in describing the presence of MAYV in Cajamarca, an Andean region of Peru. Symptoms are non-specific and can be confused with those of other arbovirus or bacterial infections. Molecular biology methods such as RT-PCR allow the timely and accurate detection of MAYV and could thus be considered as a tool for surveillance in endemic areas.This research was supported by the Bio & Medical Technology Development Program of the National Research Foundation (NRF) funded by the Korean government (MSIT) (No. 2015M3A9B6073666 ). This study was supported by CONCYTEC Peru , under the contract No 164-2016-FONDECYT, Lima, Peru. Incentive for Research of the Universidad Peruana de Ciencias Aplicadas (No. UPC-C-01-2019), Lima, Peru. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
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Schwartz, Emily. "Spatiotemporal Distribution of Genus Culex (Diptera: Culicidae) in USF Ecopreserve, Hillsborough County, Florida." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5122.
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Within the state of Florida, there are three arboviruses of public health importance that can cause neuroinvasive disease in humans: West Nile Virus, Saint Louis Encephalitis Virus, and Eastern Equine Encephalitis Virus. Mosquitoes (Diptera: Culicidae) within the genus Culex are known and suspected vectors of these diseases. The vectors of these diseases can be present in urban wetland habitats that allow for exposure to residential communities. Vector ecology must be investigated in order to understand the dynamics of disease transmission. In Hillsborough County, Florida the spatial and temporal distribution of these vectors are not well established. An ecological study was conducted in the University of South Florida's Ecopreserve using trapping methodologies to sample the adult and gravid females as well as collect the egg population. Collections were made at three spatial points for the duration of July through December 2013 and compared to meteorological variables. Culex erraticus, a proposed bridge vector of Eastern Equine Encephalitis, was the most abundant adult species and gravid female captured. Culex nigripalpus, primary Floridian vector of Saint Louis Encephalitis and bridge vector of West Nile Virus, was the second most abundant adult species caught as well as the majority of eggs collected. Based on the results collected, the presence of Culex erraticus and Culex nigripalpus was confirmed. The majority of Culex erraticus adults were collected in September and October and Culex nigripalpus adults were the highest in July and August. The results of the gravid and egg collection generated crucial insight regarding methodology for studying vector ecology within this urban wetland habitat. However, modeling at spatial points based on meteorological variables yielded inconsistent results that illicit further investigation regarding these arboviral vectors of disease.
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Maganga, Gaël Darren. "Identification et caractérisation des virus à ARN potentiellement pathogènes pour l'homme chez les populations de chauves-souris d'Afrique Centrale." Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20072/document.
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Le nombre de virus détectés chez les chauves-souris est en augmentation, la plupart étant des virus à ARN. L'identification chez différentes espèces de chauves-souris, de virus ayant été responsables d'épidémies voire de pandémies chez l'homme (coronavirus agent du SRAS, virus Nipah et Hendra, filovirus Ebola et Marburg) a fait prendre conscience du risque que peuvent présenter ces animaux pour la santé humaine, ainsi que des possibilités réelles d'émergence de nouvelles pathologies dans les années futures. Ce travail avait donc pour objectifs: (i) d'identifier et caractériser les virus circulant au sein des populations de chauves-souris d'Afrique Centrale et (ii) d'explorer et d'identifier des déterminants bioécologiques, qui pourraient expliquer la richesse virale observée chez certaines espèces de chauves-souris rencontrées en Afrique tropicale forestière. A partir d'un total de 3472 individus testés, représentant 16 espèces provenant du Gabon, de la République du Congo et de la République Centrafricaine, nous avons confirmé la présence du virus Marburg chez les roussettes d'Egypte (Rousettus aegyptiacus) au Gabon, et mis en évidence des séquences virales de paramyxovirus très proches de virus zoonotiques émergents (les virus Nipah et Hendra) et réémergents (virus des oreillons) chez des chauves-souris frugivores. Des séquences de nouveaux coronavirus, flavivirus et paramyxovirus ont été également identifiées. Par ailleurs, la fragmentation de l'aire de distribution et le type de gîte ont été identifiés comme des déterminants de la richesse virale chez 15 espèces de chauves-souris d'Afrique Centrale. Les chauves-souris en Afrique Centrale seraient donc des réservoirs de virus apparentés à des virus pathogènes pour l'homme. Ces animaux pourraient donc être à l'origine de l'émergence des encéphalites à hénipavirus en Afrique et de la réémergence de certaines maladies humaines comme les oreillons, la rougeole. Des recherches futures s'orienteront vers la poursuite de la caracterisation génétique des virus détectés chez les chauves-souris d'Afrique Centrale et la détermination du risque zoonotique associé à ces virus. Des études écologiques seront également réalisées pour identifier les facteurs de risque d'émeregence des virus de chauves-souris potentiellement pathogènes pour l'hommeThe number of viruses détected in bats is growing, the most common are RNA viruses. The identification in different bat species of viruses that cause major epidemics or pandemics in human such as SARS coronavirus, Nipah and Henda viruses, the filoviruses Ebola and Marburg has raised awareness of potential risk that these animals may present to human health, as well as real possibilities of development of new diseases in future years. This work had two objectives: (i) to identify and characterize the viruses circulating in populations of bats in Central Africa and (ii) to explore and identify bioecological factors that could explain the viral richness observed in some bats species seen in tropical Africa forest. From 3472 individuals tested accounting for 16 species from Gabon, Congo and the Central African Republic, we established the presence of Marburg virus in Egyptian fruit bats (Rousettus aegyptiacus) in Gabon and identified viral sequences of paramyxoviruses close related to emerging and re-emerging zoonotic paramyxoviruses (Nipah virus, Hendra viruses and mumps virus) in fruit bats. Sequences of novel coronaviruses, paramyxoviruses and flaviviruses have also beenidentified. Moreover, the fragmentation of the range and roost type have been identified as determinants of viral richness in 15 bats species of Central Africa. Bats in Central Africa thus would be reservoirs of viruses related to viruses pathogenic for humans. These animals would lead to the emergence of encephalitis Henipavirus in Africa and the reemergence of certain human diseases such as mumps, measles. Further research will be conducted to continue the genetic characterization of viruses detected from bats in Central Africa and to determine the zoonotic risk associated with these viruses. Ecological studies will also be performed to identify the risk factors for the emergence of bats viruses potentially pathogenic for humans
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Lebredonchel, Hugo. "Diversité des prasinovirus (phycodnaviridae) et contrôle par les facteurs environnementaux." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066005/document.
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Les virus sont les entités les plus abondantes dans les océans et ces parasitoïdes interagissent avec chaque composante de la biosphère marine, soit par la sélection des communautés d'hôte, soit en influençant les cycles biogéochimiques. Cependant, l'impact des conditions environnementales sur ces assemblages viraux complexes est encore mal compris. L'objectif de ce travail est de comprendre comment les assemblages viraux sont influencés par les facteurs environnementaux. Durant un suivi mensuel des communautés de mars 2013 à avril 2014, nous nous sommes intéressés à un système hôte-virus abondant et largement répandu, les communautés de microalgues Mamiellophyceae et leurs Prasinovirus. Durant ces études, des approches de PCR quantitative et de séquençage massif ont été développées afin de décrire les populations environnementales présentes au sein du Golfe du Lion. Les populations de Mamiellophyceae dominent le compartiment des picoeucaryotes photosynthétiques, avec des dynamiques fortes au cours de l'année. Les communautés de Prasinovirus reflètent les dynamiques de leurs hôtes, elles-mêmes en lien avec les facteurs environnementaux. En revanche, la dispersion ainsi que le maintien des virions semblent directement impacté par les conditions environnementales, comme la température et l'hydrodynamisme. Certains groupes viraux, comme les virus d'Ostreococcus, sont inféodés aux lagunes et aux zones côtières, suggérant ainsi que la dispersion des populations virales est limitées par la présence des hôtesViruses are the most abundant biological entities in oceans and they every member of the marine biosphere is affected by them, they influence the composition of communities and influence biogeochemical cycles. However, the influence of environmental conditions on complex viral populations is still poorly understood. The aim of this study is to understand how environmental factors influence viral communities. We followed viral communities monthly from March 2013 to April 2014 and investigated the host-virus system of Mamiellophyceae communities and their prasinoviruses, a model sytem that is abundant and widespread. Prasinovirus-host populations from the Gulf of Lion were quantified by PCR amplification and analysis of genetic marker genes and high throughput sequencing. Photosynthetic populations of picoeukaryotes were dominated by populations of Mamiellophyceae showing high levels of quantitative and qualitative annual variations that were related to environmental factors. Prasinovirus communities mimed host dynamics, but viral dispersion and persistence appeared to be impacted directly by environmental conditions such as temperature and hydrodynamics. Several viral groups, such as Ostreococcus viruses, were specific to lagoonal and coastal areas, suggesting that their dispersal is limited by host occurrence
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Yang, Wan. "Airborne Transmission of Influenza a Virus in Indoor Environments." Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/77340.
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Despite formidable advances in virology and medicine in recent decades, we know remarkably little about the dynamics of the influenza virus in the environment during transmission between hosts. There is still controversy over the relative importance of various transmission routes, and the seasonality of influenza remains unexplained. This work focuses on developing new knowledge about influenza transmission via the airborne route and the virus' inter-host dynamics in droplets and aerosols.
We measured airborne concentrations of influenza A viruses (IAVs) and size distributions of their carrier aerosols in a health center, a daycare center, and airplanes. Results indicate that the majority of viruses are associated with aerosols smaller than 2.5 µm and that concentrations are sufficient to induce infection.
We further modeled the fate and transport of IAV-laden droplets expelled from a cough into a room, as a function of relative humidity (RH) and droplet size. The model shows that airborne concentrations of infectious IAV vary with RH through its influence on virus inactivation and droplet size, which shrinks due to evaporation. IAVs associated with large droplets are removed mostly by settling, while those associated with aerosols smaller than 5 µm are removed mainly by ventilation and inactivation.
To investigate the relationship between RH and influenza transmission further, we measured the viability of IAV in droplets at varying RHs. Results suggest that there exist three regimes defined by RH: physiological conditions (~100% RH) with high viability, concentrated conditions (~50% to ~99% RH) with lower viability, and dry conditions (<~50% RH) with high viability. A droplet's extent of evaporation, which is determined by RH, affects solute concentrations in the droplet, and these appear to influence viability.
This research considerably advances the current understanding of the dynamics of the influenza virus while it is airborne and provides an explanation for influenza's seasonality. Increased influenza activity in winter in temperate regions could be due to greater potential for IAV carrier aerosols to remain airborne and higher viability of IAV at low RH. In tropical regions, transmission could be enhanced due to better survival of IAV at extremely high RH.Ph. D.
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Srivatsavai, Venkata Suresh Kumar Huettel Robin Norton. "Identification, distribution and vector biology of brome mosaic virus of wheat in Alabama." Auburn, Ala., 2005. http://hdl.handle.net/10415/1266.
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Firley, Delphine. "Structures et propriétés électroniques d'un inhibiteur de l'intégrase du VIH de la série des styrylquinoléines et de ses progéniteurs." Châtenay-Malabry, Ecole centrale de Paris, 2005. http://www.theses.fr/2005ECAP0997.
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Le SIDA est une maladie épidémique mondiale due à un rétrovirus, le VIH. Vu la lourdeur des traitements et la résistance du virus, l'intégrase (IN), troisième enzyme du VIH-1, s'est avérée être une nouvelle cible thérapeutique. Les dérivés des styrylquinoléines, dénuées de cytotoxicité, sont de potentiels inhibiteurs de l'IN. La molécule la plus prometteuse est l'acide (E)-8-hydroxy-2-[2-(4,5-dihydroxy-3-méthoxyphényle)-éthényle]-7-quinolinecarboxylique (FZ41) synthétisée à partir de l'acide 8-hydroxy-7-quinaldine carboxylique et du 3,4-dihydroxy-5-methoxybenzaldéhyde. Notre travail a porté sur la caractérisation à l'échelle moléculaire et atomique de ces molécules. Des études de cristallographie classique et de haute résolution ont été menées sur ces composés. Pour comprendre le mécanisme d'inhibition et mimer l'interaction " FZ41-IN ", différents essais de complexation de l'acide 8-hydroxy-7-quinaldine carboxylique avec des cations divalents ont été menés. Les cristaux des complexes de magnésium et de sodium, nous ont permis de comprendre l'interaction de l'acide 8-hydroxy-7-quinaldine carboxylique avec des cations métalliques. L'étude structurale de la FZ41 a révélé une molécule de forme s-trans zwitterionique. Une étude par diffraction X haute résolution a pu être effectuée sur les progéniteurs. Nous avons déterminé leur densité électronique et leur potentiel électrostatique. Pour compléter cette étude et l'appliquer à la FZ41, nous avons eu recours aux calculs ab-initio. Nous avons montré que les propriétés électrostatiques et les charges atomiques sont quasi-transférables. Ce résultat est important pour comprendre l'inhibition de l'IN par des styrylquinoléinesAIDS is a world epidemic disease due to the infection by a retrovirus, the HIV. Considering the heaviness of these treatments and the resistance of the virus, the integrase (IN), the third enzyme of HIV-1 has reached as a legitimate new drug target. The styrylquinoline derivatives, devoid of cytotoxicity, have proved to be potent HIV-1 IN inhibitors. The most promising molecule is the (E)-8-hydroxy-2[2-(4,5-dihydroxy-3-methoxyphenyl)-ethenyl]-7-quinolinecarboxylic acid (FZ41) synthesized from two progenitors : 8-hydroxy-7-quinolinic acid and 3,4,5-methoxy-dihydroxy-benzaldehyde. Our work concerns the characterization on a molecular and atomic scale of these molecules. Studies of classic crystallography and high resolution were undertaken on these compounds. To understand the integration mechanism and mime the “FZ41-Integrase” interaction, various tests of complexation of the 8-hydroxy-7-quinolinic acid with metallic cations were undertaken. The crystals of the magnesium and sodium complexes are to get us a comprehensive understanding of the interaction with the metallic mono and bivalent cations. In spite of the presence of twinning, the structural study of FZ41 reveals a s-trans form and zwitterionic molecule. A study by high resolution X-ray diffraction could be carried out on the progenitors. We have determined the electronic density and the electrostatic potential. To supplement this study and to apply to the FZ41, we had recourse to ab-initio calculations. We showed that the electrostatic properties and atomic charges are quasi-transferable. This result is of particular significance to understand of the inhibition of IN by styrylquinolines as the FZ41
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Rocheleau, Jonathan V. "Membrane distribution and dynamics of a synthetic ganglioside and its interaction with sendai virus." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0017/NQ58160.pdf.
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Drewes, Stephan [Verfasser]. "Reservoir-driven inhomogeneous distribution of human Puumala virus cases in Central Europe / Stephan Drewes." Greifswald : Universitätsbibliothek Greifswald, 2016. http://d-nb.info/1116432986/34.
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Mackasmiel, Lucas A. "Assessing the Distribution and Impact of Bean pod mottle virus (BPMV) as a Re-emerging Virus, and Soybean mosaic virus (SMV) in Soybean Grown in Virginia." Diss., Virginia Tech, 2004. http://hdl.handle.net/10919/28836.
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Bean pod mottle virus (BPMV, Genus Comovirus, Family: Comoviridae)is an important virus in soybean (Glycine max (L.) Merrill), causing quality and yield loss due to seed coat mottling and seed weight reduction. Although BPMV has been known in Virginia since 1958 and has always been regarded as causing negligible losses, its impact is changing as BPMV incidence has increased in many soybean growing areas of Virginia and the USA in general. From 1997 to 2001, a total of five BPMV isolates (V-W1, V-W2, V-S98-1, V-S98-15 and V-S01-10) were collected in Virginia and characterized. In this study, the effects of these isolates were studied, alone or with Soybean mosaic virus (SMV, Genus Potyvirus, Family Potyviridae) strain SMV G1, and isolates S98-51 and S98-52, on selected soybean cultivars. Individual isolates of BPMV showed variable symptom severity, and resulted in yield loss of between 40.4 to 58.1%, while SMV caused 23.7% in the most severe interactions. Up to 100% yield loss was realized from double inoculations of selected BPMV and SMV isolates, BPMV V-S98-1 + SMV S98-52 and BPMV S98-15 + SMV S98-52 on Hutcheson and Hutcheson Roundup Ready® (BC5) soybeans, respectively. Time of inoculation, a critical factor in the impact of many virus diseases, affected seed coat mottling in four cultivars and seed weight in two cultivars, in tests with four BPMV isolates and three stages of soybean development. All BPMV isolates inoculated to plants at vegetative stage V1-V3 severely increased seed coat mottling and reduced seed weight than those inoculated at V4-V6 and reproductive stage R1-R3. Seedlings grown from non-mottled seeds germinated more uniformly had fewer thin-stemmed seedlings and grew faster than those grown from mottled seeds. Inoculation of various cultivars and breeding lines showed that there was no correlation between the severity of virus-induced foliar symptoms, relative accumulation of SMV, and extent of seed coat mottling. Thus, by avoiding the presence of BPMV at an early growth stage through proper timing of planting to avoid vectors, proper cultural practices like weed control, use of SMV free seeds, and chemical control, it is possible to greatly improve seed quality and reduce yield losses in soybean.Ph. D.
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Holzgrefe, William Andrew. "Rabies in Virginia, 1989-2003: With particular attention to animals, geographic distribution, and virus variant." VCU Scholars Compass, 2004. http://scholarscompass.vcu.edu/etd/1225.
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Objectives: The description of the raccoon rabies epizootic in Virginia over fifteen years (1989-2003). Methods: Using simple statistical methods and a geographic information system (GIS)-based approach, and fifteen years worth of animal surveillance data, the progress of this epizootic has been charted in terms of the geographic spread of the disease, the major animal species affected by the disease and its spread, and the exposure and risk to humans and livestock animals presented by the expansion of the geographic range. Results: The resulting descriptive study illustrates the eastward expansion of the epizootic, the mushrooming of the disease in the northern region of the state, and the rates of rabid animal submissions for every health district and selected important animal species. Human exposures to rabid animals are mapped and compared to human population densities. Strong seasonal trends in human and livestock exposures to rabid animals are illustrated, with animal exposures predominating in the spring and autumn, while human exposures peak in the summer; also shown is the possible emergence of new strains of rabies virus and the possible extinction of the previously dominant strain. Conclusions: Some potentially positive developments have been found, such as substantially increasing levels of bat submissions across time, which may signify greater public awareness of the disease. Serious deficiencies in the monitoring system are discussed, centering on the accuracy and comparability of the data collected, and suggestions for improvement are offered. While several potentially interesting new areas of study are put forward, the standard approach to rabies control (pet vaccination and control, education of at-risk populations, orally vaccinating wild animals) is not found to be in need of significant modification, aside from the specifics of the approach being tailored to better meet local conditions.
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Nigro, Judith A. "The distribution of the Sin Nombre virus in the tissues and urine of deer mice /." abstract and full text PDF (UNR users only), 1999. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1395239.
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Leclercq, Le Quillec Françoise. "Dynamique spatio-temporelle du complexe bydv (barley yellow dwarf virus), et effet d'un traitement de semences sur la distribution des vecteurs et des virus." Paris 11, 1992. http://www.theses.fr/1992PA112363.
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La presente etude se propose de suivre, sur trois annees: la cinetique de distribution aerienne et en parcelles d'orge d'hiver des vecteurs et des virus de la jaunisse nanisante de l'orge (vjno), la reponse du processus epidemique a un traitement aphicide, l'imidacloprid. Le suivi des flux aeriens des vecteurs et des virus de la jno revele: la preponderance de l'espece vectrice r. Padi a l'automne, surtout vectrice des isolats de type pav, le role majeur joue par m. Dirhodum au printemps, qui, principal vecteur d'isolats de type mav, participe egalement et de facon non negligeable a la vection des isolats de type pav, le faible impact des s. Avenae captures, essentiellement vecteurs de rares isolats de type mav. L'evolution temporelle des vecteurs et des vjno est assez stable d'une annee a l'autre. Elle relativise l'importance de la dissemination secondaire des vjno qui intervient essentiellement au printemps, a une periode ou les orges, taillees ou en montaison, sont assez tolerantes a l'infection virale. L'etude de la repartition spatiale confirme le quasi arret ou l'extreme lenteur du processus infectieux en hiver. Ces resultats ont d'importantes consequences pratiques: mettant l'accent sur l'importance des contaminations primaires, ils permettent de simplifier les methodes de prevision et de lutte qui peuvent se limiter a l'importance des vols et au pouvoir virulifere des pucerons captures a l'automne. Dans ces conditions spatio-temporelles d'infestation et d'infection, le traitement de semences eprouve reduit notablement l'infestation primaire, et empeche la dissemination secondaire de la maladie. Particulierement remanente, cette matiere active ne limite cependant pas la contamination printaniere des parcelles par m. Dirhodum. Des experiences en conditions controlees confirment la persistance de cette espece de puceron sur de jeunes plantes d'orge traitees a l'imidacloprid, et la vection tout aussi efficace d'isolats de type pav et mav sur plantes traitees et temoins
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Gautier, Nicolas Ferre Virginie. "Distribution des sous-types du VIH-1 d'une cohorte de patients nantais analyse du polymorphisme, impact sur la résistance /." [S.l.] : [s.n.], 2005. http://theses.univ-nantes.fr/thesemed/PHgautier.pdf.
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Strappe, Padraig Michael. "Quantification of proviral load and the distribution of drug resistant mutations in human immunodeficiency virus infection." Thesis, University College London (University of London), 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271496.
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Klingseisen, Bernhard Johann. "Spatio-temporal modelling of bluetongue virus distribution in Northern Australia based on remotely sensed bioclimatic variables." Thesis, Curtin University, 2010. http://hdl.handle.net/20.500.11937/726.
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The presence of Bluetongue virus (BTV) in Northern Australia poses an ongoing threat for animal health and although clinical disease has not been detected in livestock, it limits export of livestock from the infected areas. BTV presence is governed by variable environmental conditions, which influence vector and host habitats. The National Arbovirus Monitoring Program (NAMP) was established to determine the extent of virus activity and control the risk of infection spread. Groups of young cattle, previously unexposed to infection, are regularly tested to detect evidence of transmission. This approach is labour and cost intensive and difficult to operate in the remote areas of Northern Australia. The resulting data are therefore characterised by spatial and temporal gaps. The aim of this research is to assess the use of remotely sensed environmental and climatic data as a means of predicting the distribution of BTV seroprevalence throughout Northern Australia to complement conventional surveillance.Environmental factors relating to the viruses’ host and vector habitats and the transmission cycle of BTV have been identified based on the extensive review of virus ecology. Different data sources have been assessed to provide sufficient spatial and temporal coverage for the definition of spatio-temporal environmental variables that can be used to explain and predict the distribution of BTV. Following this assessment, satellite data products from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Tropical Rainfall Measuring Mission (TRMM) were acquired for the Pilbara in Western Australia, and the Northern Territory. These were reprojected and processed into spatio-temporal variables for the period between the years 2000 and 2009. Due to uncertainty in the precision of the geographic location and timing of animals tested for seropositivity, summary statistics of bioclimatic variables were generated at the station (i.e. property) level for each year. Different combinations of these variables, including vegetation greenness and phenology, land surface temperature and precipitation were screened for correlation with BTV presence using a Generalised Additive Model approach. A final model was developed to predict the presence or absence of BTV seropositivity on the basis of statistical significance of the remotely sensed predictor variables, and informed by knowledge of virus ecological principles.The model, based on the maximum seasonal Normalised Difference Vegetation Index (NDVI), and mean and maximum land surface temperature variables provided excellent discriminatory ability and the basis for the generation of prediction maps of BTV seropositivity for the first eight years. Besides internal assessment, the model’s predictive capabilities were validated using monitoring data from the season 2008/09.It has been demonstrated that the predictions are useful in complementing complement NAMP surveillance by identifying areas at higher risk for seropositivity in cattle, which aids planning of livestock movement and further monitoring activities. Uncertainty in the model was attributed to the spatio-temporal inconsistency in the precision of the available serosurveillance data. The discriminatory ability of models of this type could be further improved by ensuring that exact location details and date of NAMP BTV test events are consistently recorded.
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Helmer, Carina Monika [Verfasser]. "Investigations on the distribution and transmission of Schmallenberg virus in sheep and goat flocks / Carina Monika Helmer." Hannover : Bibliothek der Tierärztlichen Hochschule Hannover, 2013. http://d-nb.info/1046711431/34.
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AL-Ibadi, Basim Ibrahim Hasan [Verfasser]. "Avian borna virus in psittacine birds : viral distribution, tropism and immune response / Basim Ibrahim Hasan AL-Ibadi." Gießen : Universitätsbibliothek, 2016. http://d-nb.info/1081897791/34.
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Kelu, Ken Bisabu. "Distribution chez la souris gestante du transgène GFP introduit avec un virus adéno-associé du sérotype 9." Master's thesis, Université Laval, 2015. http://hdl.handle.net/20.500.11794/26500.
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La thérapie génique utilisant les vecteurs viraux est une des approches thérapeutiques possible pour le développement d’une thérapie pour les maladies génétiques mono-géniques dont l’ataxie de Friedreich (FRDA). Dans le but de vérifier l’efficacité des virus adéno-associés (AAV) à transférer la copie normale du transgène dans les tissus qu’ils infectent, nous avons insérer le gène codant pour la forme améliorée de la protéine fluorescente verte (eGFP) dans les AAV sérotype 9 (AAV9). Ces AAV recombinants (AAVr) ont été ensuite administrés aux souris femelles gestantes par voie intraveineuse et intra-péritonéale. Les résultats obtenus montrent que le transgène a été transféré à la fois dans les tissus des souris femelles ainsi que dans ceux des souriceaux.Gene therapy using viral vectors is one of the therapeutic approaches possible for the development of genetic therapies for monogenic diseases including Friedriech's Ataxia (FRDA). In order to verify the effectiveness of adeno-associated virus (AAV) to transfer a transgene in the tissues they infect, we inserted the gene encoding the enhanced form of the green fluorescent protein (eGFP) in AAV Serotype 9 (AAV9). These recombinant AAV (rAAV) were then administered by intravenous and intraperitoneal to pregnant female mice. The results obtained show that the transgene was transferred in both in the female’ mouse tissues and in those of young mice.
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Ahmed, Raza. "Epithelial distribution of foot-and-mouth disease virus RNA determined using laser micro-dissection and quantitative RT-PCR." Thesis, University of Surrey, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.442663.
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Pardieu, Claire. "Classical swine fever virus : analysis of the capsid protein core intracellular distribution and identification of its cellular partners." Thesis, University of Surrey, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.431140.
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Van, Harmelen Joanne Heidi. "Human immunodeficiency virus type-1 distribution in South Africa and the relevance of genetic diversity on vaccine design." Doctoral thesis, University of Cape Town, 1999. http://hdl.handle.net/11427/25838.
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The overall aim of this project was to investigate HIV-1 genetic diversity in South Afri ca and to characterise the immune response in mice to a South African subtype C gp120. To investigate the relationship between subtype and mode of transmission, samples were collected from individuals infected by heterosexual and male homosexual transmission from patients attending local HIV/AIDS clinics in Cape Town (n=49) and Bloemfontein (n=4). Isolates were subtyped using heteroduplex mobility assay (HMA) based on the V3-V5 region of the env geneusing reference plasmids (2 B, 2 C and 1 D) representative of local subtypes. HMA identified four env subtypes: A, B, C and D. Subtype B viruses were found in 92.9% (26/28) of the male homosexual/bisexual group and subtype C viruses in 77.2% (17 /22) of the heterosexual group. Subtype B viruses were also identified in two heterosexual patients, one patient infected by blood transfusion and in two patients with. unknown mode of transmission. Subtype D viruses were found in one male homosexual patient and one heterosexual patient and a husband and wife couple were infected with subtype A viruses. A significant association between subtype and mode of transmission (p=<0.0001) was identified, confirming two independent epidemics. To determine the subtype distribution of HIV within urban heterosexual populations throughout South Africa, samples were collected from women attending antenatal clinics in Johannesburg (n=34), Pretoria (n=S) and Durban (n=20). Samples from Bloemfontein (n=24) were taken from individuals attending an HIV/AIDS clinic. All eighty-three samples were subtyped by HMA in the env region as before. The predominant subtype circulating within the urban heterosexual population throughout South Africa was identified as subtype C (92.8%) although subtype B was also detected (7.2%). It may thus be beneficial if a HIV vaccine for South Africa is based on a subtype C model. In addition, a rapid method for identification of HIV-1 gag subtypes was developed based on restriction fragment length polymorphism (RFLP) analysis of 400bp (p17) or 650bp (p17 and 5' p24) long PCR fragments. This strategy was appl i ed to eighty-six samples (Cape Town n=47, Johannesburg n=20, Bloemfontein n=17 and Durban n=2) previously subtyped by either sequence analysis of the gag p17 region (n=31), heteroduplex mobility assay (HMA) based on the env gene (n=76), or both (n=21). RFLP analysis identified two subtype A, twenty-five subtype B, fifty-eight subtype C and one subtype D isolates. There were no discrepancies between RFLP and sequence gag subtypes, demonstrating the reliability of this method and no discordance between gag RFLP subtypes and env HMA subtypes, indicating no recombinant viruses in the genomic regions analysed.
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Grim, Devin Christine. "La Crosse virus and Dirofilaria immitis: Abundance of Potential Vectors in Southwestern Virginia and the Effects of Dual Infection on Aedes albopictus and Ochlerotatus triseriatus." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/46195.
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Microfilarial enhancement of viral transmission is well documented, however only one previously studied model used components that occur together in nature and therefore has realistic implications. La Crosse (LAC) virus encephalitis is the most common mosquito-borne illness affecting children in the United States. LAC virus is prevalent in the Great Lake and Mid-Atlantic states and coincidently this area overlaps the region of highest infection for Dirofilaria immitis, the nematode that cause canine heartworm disease. Ae. albopictus and Oc. triseriatus are important vectors of La Crosse virus and among the numerous species able to transmit D. immitis. In this study, Aedes albopictus and Ochlerotatus triseriatus were infected with La Crosse virus and Dirofilaria immitis to determine the effects of dual infection on the dissemination and transmission of the virus.
The effects of dual infection varied between the species tested. Ae. albopictus had significantly higher tolerance to D. immitis infection than Oc. triseriatus. Dissemination for dually infected Ae. albopictus were higher than the control group for all days tested, except one. Transmission rates for D. immitis infected Ae. albopictus were significantly higher than the control group on day 14 post infection. No microfilarial enhancement of viral dissemination or transmission was observed for Oc. triseriatus. The infection, dissemination, and tranmission rates were low for both species compared to rates of previous studies. Low rates could be a result of low susceptibility for the strains tested.
In a second study, mosquitoes were collected from two counties in Southwestern Virginia to determine the abundance of potential La Crosse virus and D. immitis vector species. The abundance and distribution of mosquito species were examined in 2003 and 2004 using gravid traps. An unexpected finding was the significant increase in the abundance of Ochlerotatus japonicus. In 2003, collections were made over 192 trap nights from June to August yielding 5,879 mosquitoes of which only 24 were Oc. japonicus. In 2004, 12,151 mosquitoes were trapped from June to September over 160 trap nights. Oc. japonicus was the second most abundant mosquito species and the dominant Ochlerotatus species collected in gravid traps. Oc. japonicus was collected in low numbers in June, but the abundance increased significantly in July and remained consistent throughout the rest of the season. Of the other major mosquito species collected in this study, only Aedes albopictus exhibited a similar seasonal pattern as Oc. japonicus. Other biological similarities of Oc. japonicus and Ae. albopictus are discussed.Master of Science in Life Sciences
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Fischer, Kerstin [Verfasser]. "Molecular studies on the virus diversity and virus distribution in bats in Germany and development of a novel Enzyme-linked Immunosorbent Assay for the detection of henipavirus antibodies / Kerstin Fischer." Hannover : Bibliothek der Tierärztlichen Hochschule Hannover, 2016. http://d-nb.info/1124565914/34.
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André, Pascal. "Superantigène et immunodépression liée au VIH : à propos de la distribution du TCR V [bêta]12 sur les lymphocytes T CD4 de 46 personnes infectées par le VIH." Montpellier 1, 1996. https://tel.archives-ouvertes.fr/tel-00006148.
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Pham, Bach-Nga. "Distribution des populations lymphocytaires t intra-hepatiques dans les hepatites chroniques liees au virus b ou au virus c ; correlation de l'infiltrat t cd4+ avec la replication virale et biais d'expression des genes v beta des recepteurs t." Paris 11, 1997. http://www.theses.fr/1997PA11T027.
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Van, Heuserswyn Fran. "Diversité génétique, prévalence et distribution géographique des lentivirus de chimpanzés et gorilles sauvages au Cameroun : implications pour l'origine de VIH-1." Montpellier 2, 2007. http://www.theses.fr/2007MON20098.
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Les primates non-humains africains sont les hôtes naturels de nombreux virus de l'immunodéficience simienne (SIV), dont deux, SIVcpz et SIVsmm, infectant des chimpanzés et des mangabés enfumés, sont respectivement à l'origine de VIH-1 et VIH-2. Cependant, les données sur la prévalence, la dissémination et la diversité génétique de SIVcpz chez leurs hôtes en milieu naturel sont limitées et, de fait, n'ont pas permis la mise en évidence d'un réservoir de ces virus au sein des chimpanzés sauvages. Les objectifs de cette thèse sont d'identifier et de caractériser les SIV circulants chez les grands singes au Cameroun, ainsi que les réservoirs naturelles qui sont à l'origine de HIV-1. A l'aide d'une méthode de collecte non invasive, nous avons mis en évidence que les chimpanzés de la partie Ouest de l'Afrique Centrale (Pan troglodytes troglodytes) sont le réservoir naturel du VIH-1. Nous avons plus particulièrement identifié l'origine du VIH-1 M (pandémique) et VIH-1 N (non pandémique) dans différentes populations de chimpanzés géographiquement éloignés, respectivement dans la partie Est et la partie Centrale de Sud Cameroun. Pour la première fois, nous avons identifié des virus apparentés au VIH groupe O, designés SIVgor, chez les gorilles des plaines de l'ouest (Gorila gorilla gorilla). Cependant, les analyses phylogénétiques suggèrent que des chimpanzés représentent le réservoir initial des virus de gorilles. Malgré la parenté proche entre les souches SIVgor identifiés et VIH-1 O, ils restent encore trop divergents pour représenter le précurseur immédiat de ce groupe de VIH-1. Ces résultats montrent que non seulement les chimpanzés, mais aussi les gorilles représentent un réservoir de lentivirus de primates, connus pour pouvoir traverser les barrières d'espèce et engendrer une épidémie tel que le VIH/SIDA. De fait, l'étude des infections lentivirales dans les populations de grands singes sauvages n'est pas seulement indispensable pour identifier l'origine des VIH-1, mais permet également la mise au point d'outils diagnostiques pouvant d'une part détecter la présence de nouveaux SIV chez les chimpanzés et gorilles et d'autre part étudier si de nouvelles infections de SIVcpz ou SIVgor ont été transmises à l'Homme sans être détectésChimpanzees and SIVsmm infecting sooty mangabeys, are considered to be the immediate source of HIV-1 and HIV-2 respectively. However, information about the prevalence, distribution and genetic diversity of SIVcpz in their primate hosts in the wild was very limited, and evidence for the existence of a virus reservoir was lacking. In this thesis, we aimed to identify and characterize SIVs circulating among great ape species in Cameroon and to identify the natural reservoirs of HIV-1. Using non-invasive sampling methods, we identified the West central African chimpanzees (Pan troglodytes troglodytes) as the natural reservoir of HIV type 1. We traced the origin of HIV-1 M (pandemic) and HIV-1 N (non-pandemic) to geographically isolated chimpanzee communities in southeast and south central Cameroon respectively. For the first time, we identified viruses closely related to HIV-1 group O, designated SIVgor, in wild Western lowland gorillas (Gorilla gorilla gorilla). Phylogenetic analyses, however, indicated that chimpanzees are likely to be the original reservoir of these gorilla viruses. In spite of the close relationship between the identified SIVgor strains and HIV-1 group O, they are still too divergent to represent the immediate precursor of this group of HIV-1. These data show that chimpanzees and also gorillas in Cameroon represent a potential source of human infection. The non-invasive survey of wild ape populations was therefore not only indispensable for identifying the primate origin of HIV-1, but also for ensuring that additional reservoirs of human immunodeficiency viruses are not missed. The V3 peptides of the newly identified SIVcpz and SIVgor strains will be of particular use to investigate whether additional SIVcpz and SIVgor transmissions to humans have occurred but have gone unrecognized
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Castéra, Laurent Pawlotsky Jean-Michel. "Rôle de la distribution en quasi espèces des virus d'hépatites dans la résistance aux traitements antiviraux et l'évolution de la maladie hépatique." Créteil : Université de Paris-Val-de-Marne, 2007. http://doxa.scd.univ-paris12.fr:8080/theses-npd/th0405106.pdf.
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Thèse de doctorat : Virologie : Paris 12 : 2007.Version électronique uniquement consultable au sein de l'Université Paris 12 (Intranet). Titre provenant de l'écran-titre. Bibliogr. : 260 réf.
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Abuelezam, Nadia. "Mathematical AIDS Epidemic Model: Preferential Anti-Retroviral Therapy Distribution in Resource Constrained Countries." Scholarship @ Claremont, 2009. http://scholarship.claremont.edu/hmc_theses/67.
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HIV/AIDS is one of the largest health problems the world is currently facing. Even with anti-retroviral therapies (ART), many resource-constrained countries are unable to meet the treatment needs of their infected populations. ART-distribution methods need to be created that prevent the largest number of future HIV infections. We have developed a compartment model that tracks the spread of HIV in multiple two-sex populations over time in the presence of limited treatment. The model has been fit to represent the HIV epidemic in rural and urban areas in Uganda. With the model we examine the spread of HIV among urban and rural regions and observe the effects of preferential treatment to rural areas on the spread of HIV in the country as a whole. We also investigate the effects of preferentially treating women on the spread of HIV. We find that preferentially treating urban women produces the most dramatic effect in reducing the number of infected male and females in rural and urban areas.
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Castéra, Laurent. "Rôle de la distribution en quasi espèces des virus d'hépatites dans la résistance aux traitements antiviraux et l'évolution de la maladie hépatique." Paris 12, 2007. https://athena.u-pec.fr/primo-explore/search?query=any,exact,990004051060204611&vid=upec.
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Dans la première partie de ce travail, nous nous sommes intéressés à la signification de la stéatose hépatique au cours de l'hépatite chronique C. Celle-ci est présente dansplus de 50% des cas et pourrait contribuer à laprogression de la maladie. Nous avons montré, chez 96 patients ayant eu 2 biopsies hépatiques et non traités dans l'intervalle, que la progression de la fibrose était fortement associée à l'aggravation de la stéatose. Nous avons également montré chez 151 patients traités ayant eu deux biopsies hépatiques avec une stéatose sur la biopsie initiale, qu'il existait une amélioration significative de la stéatose en cas d'éradication virale uniquement chez les patients infectés par le génotype 3. Nos résultats suggèrent que 2 types distincts de stéatose hépatique peuvent être rencontrés au cours de l'hépatite chronique C : une stéatose "métabolique" chez les patients infectés par un génotype non 3 présentant pour lamajorité des facteurs de risque métaboliques classiques (surpoids, diabète, dyslipidémie, alcool) ; une stéatose "virale" chez les patients infectés par le génotype 3, par un effet cytopathogène direct du virus de l'hépatite C dont les mécanismes restent à élucider. Dans la deuxième partie, nous nous sommes intéressés aux mécanismes impliqués dans la résistance du virus del'hépatite B (VHB) à la lamivudine (inhibiteur de la reverse transcriptase (RT) du VHB). Celle-ci est observée avec une incidence annuelle de 20% et peut conduire à une aggravation de la maladie hépatique. Nous avons caractérisé de façon approfondie les dynamiques des "quasi espèces" des variants du VHB chez 4 patients résistants à la lamivudine. L'échappement virologique était précédé de 2 à 4 mois par l'émergence de variants de quasi espèces porteurs de substitutions aminoacidiques au sein de la RT au niveau du site catalytique YMDD à la position 204 (rtM204V/I). Trois patients ont une transition progressive d'une population initiale de variants YMDD sauvages vers une population de variants tous résistants à la lamivudine alors que le patient restant avait une dynamique d'évolution de profil fluctuant. Nos résultats suggèrent que l'optimisation individuelle des traitements nécessitera l'utilisation de méthodes sensibles permettant de détecter l'émergence de variants viraux résistants avant que ceux-ci acquièrent les capacités de réplication optimalesIn the first part of this work, we studied the significance of hepatic steatosis, a frequent histological finding in patients with chronic hepatitis C, that has been suggested to influence disease progression. We have known that, in 96 untreated patients with paired liver biopsies, fibrosis progression was strongly associated with worsening of steatosis. We have shown also in 151 treated patients with steatosis, a significant improvement in steatosis in patients infected with HCV genotype 3, who achieved sustained viral clearance. Our results suggest that two distinct forms of hepatocellular steatosis can be seen in patients with chronic hepatitis C. Classical metabolic risk factors for steatosis account for the vast majority of cases os steatosis in patients infected by non genotype 3 HCV strains. In contrast, in patients infected by HCV genotype 3, steatosis is generally induced by the virus itself through a direct cytopathic effect, the mechanisms of which remain debated. In the second part of this work, we studied the mechanisms of hepatitis B virus (HVB) resistance to lamivudine (first approved inhibitor of BHV reverse transcriptase (RT)), which occurs with a 20% annual incidence and can lead to hepatic disease exacerbation. We extensively characterized the dynamics of HBV quasispecies variant populations in four HBV-infected patients who developed lamivudine resistance. Virological breakthrough was preceded by 2 to 4 months by the emergence quasispecies variants bearing amino acid substitutions at RT position 204, i. E. , within the YMDD catalytic motif (rtM204V/I). Three patients had a gradual switch from a YMDD variant population at baseline to a 100% lamivudine resistant variant population, whereas the remaining patient had a fluctuating pattern of resistance variant dynamics. Our findings suggest that individual treatment optimization will require sensitive methods capable of detecting the emergence of viral resistance before the relevant variant acquire optimal replicative capacities
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Pritchard, Edgar Jonathan. "Seasonal abundance and distribution of mosquito species (Culicidae) in southwestern Québec and their potential role as vectors of West Nile Virus." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=86523.
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West Nile Virus (WNV) is maintained in bird populations by ornithophilic mosquito vectors. It invades mammalian hosts through the action of bridging vectors, which are either indiscriminant feeders or arise when strict feeding preferences break down. Patterns of seasonal abundance of mosquito species along an East-West transect through urban, suburban and rural habitats from Montréal to Rigaud, Québec, were used in conjunction with temperature and rainfall data to develop models to predict population abundance of three mosquito species, Aedes vexans (Meigen, 1830), Aedes triseriatus (Say, 1823) and Culex pipiens (Linnaeus, 1758). All three species have been implicated as important vectors of WNV. Modelling predicted exponential population growth for Ae. vexans and Ae. triseriatus at high temperatures and precipitation levels in the Rural and Suburban environments. More moderate conditions have additive and/or diminutive effects on population abundance. In the Rural habitat, Ae. vexans may outcompete Cx. pipiens. Culex pipiens was predicted to be more resistant to desiccation and wash-out conditions, most likely due to the availability of artificial breeding habitats, and was the only species predicted to exhibit exponential growth in the Urban environment. Blood meal analysis revealed that 88.56% of mosquitoes fed on humans, and 5.97% on raccoons. The remainder fed on a number of other mammals, but none fed on birds. These findings may explain the low level of WNV in southwestern Québec.Le maintien du virus du Nil occidental (VNO) dans les populations aviaires est assuré par les populations de moustiques ornithophiles. Sa propagation aux hôtes mammifères est due aux vecteurs passerelles soit lors de changement d'habitudes alimentaires strictes ou grâce aux espèces qui se nourrissent de façon non discriminatoire. L'échantillonnage des populations saisonnières de moustiques le long d'un transect est-ouest dans les secteurs urbains, de banlieue (suburbains) et ruraux de Montréal à Rigaud, Québec, a été utilisés en combinaison avec les mesures de températures et de précipitations afin de développer un modèle de prédiction des populations espèces : Aedes vexans (Meigen, 1830), Aedes triseriatus (Say, 1823) et Culex pipiens (Linnaeus, 1758). Les trois sont considérées comme des vecteurs importants du VNO. Le modèle prédit une croissance exponentielle de la population pour Ae. vexans et Ae. triseriatus à hauts niveaux de températures et de précipitations dans les environnements ruraux et suburbains. Des niveaux de températures et de précipitations modérées peuvent avoir impact positif ou négatif sur l'abondance des populations. Dans l'habitat rural, Ae. vexans peut surpasser Cx. pipiens. Les résultats ont démontré que Cx. pipiens peut être plus résistant à la sécheresse et au lavage par la pluie, sûrement dû à la présence d'habitats artificiels favorables à la reproduction, et était la seule espèce dont la croissance prédite était exponentielle en milieu urbain. L'analyse des repas sanguins a révélé que 88.56% des moustiques se sont nourris sur les humains, 5.97% sur les ratons laveurs, le reste sur d'autres mammifères, mais aucun sur des oiseaux. Ces résultats peuvent expliquer la faible prévalence du VNO dans le sud-ouest du Québec.
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Schuster, Isolde Ursula Elisabeth [Verfasser]. "Novel serological assays for determination of the distribution and of hosts of Crimean-Congo hemorrhagic fever virus / Isolde Ursula Elisabeth Schuster." Hannover : Bibliothek der Tierärztlichen Hochschule Hannover, 2017. http://d-nb.info/1150444436/34.
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Olsson, Gert E. "Nephropathia epidemica and Puumala virus occurrence in relation to bank vole (Clethrionomys glareolus) dynamics and environmental factors in northern Sweden /." Umeå : Dept. of Animal Ecology, Swedish Univ. of Agricultural Sciences, 2003. http://epsilon.slu.se/s289.pdf.
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Brown, J. K. "Trends in the Temporal Distribution and Host Plant Relations During 1988-1994, and Virus-vector Characteristics of Two Whitefly Populations in Arizona." College of Agriculture, University of Arizona (Tucson, AZ), 1996. http://hdl.handle.net/10150/214769.
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The abrupt and widespread introduction and establishment of the B type whitefly B. tabaci (Genn.) (also B. argentifollii) in Arizona in approximately 1987-1990 has given rise to unprecedented losses in vegetable and fiber crops in Arizona, and elsewhere throughout the sunbelt states. This report documents the discovery and the tracking of B type whitefly over time in Arizona crop and weed species, and reports important biological characteristics of the A and B whitefly populations with respect to host range, host preferences, and virus-vector capabilities. Here, from tracking data, we provide direct evidence that the A and B whitefly populations existed simultaneously in the state for a short period of time during 1989-90, and that by 1991, the B type population had become predominant whitefly pest and whitefly vector of plant viruses in Arizona crops. Unique host ranges and host preferences represent the most important distinctions between these two populations of B. tabaci, and are largely responsible for the altered epidemiologies of several whitefly- associated virus diseases, and for new pest problems in previously unaffected crops. From these collective data, it is possible to present an historical documentation of the emerging importance of the B whitefly as a pest and virus vector in Arizona. An unusually broad host range and the ability to induce phytotoxic disorders, set the B population apart from the historically problematic, local A type B. tabaci, and provide insights into the underlying basis of its unprecedented impact on crop production in Arizona. Baseline information about whitefly biology, host range, and virus-vector capabilities is relevant to the design and implementation of management practices aimed at controlling the whitefly as a pest and virus vector in Arizona crops.
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Rigot, Thibaud. "The space-time distribution of Palearctic Culicoides spp. vectors of Bluetongue disease in Europe." Doctoral thesis, Universite Libre de Bruxelles, 2011. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209835.
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Abstract :Bluetongue (BT) is a vector-borne infectious disease primarily transmitted to even- toed ungulates by the bite of several Culicoides species. The global distribution of BT can be attributed to the ubiquity of its vectors and its rapid spread, likely to the enhancement of human activities (intensification of animal production, trans- port, changing habitat). During the last decades, BT established in Southern Europe and more recently emerged in Northern Europe, causing the death of millions of domestic ruminants. On the same time, a Belgian research project has been set up to develop remote-sensing tools to study the EPidemiology and Space-TIme dynamicS of infectious diseases (EPISTIS). In that general framework, this thesis aimed to study the space-time distribution of the main Culicoides vectors occurring in Italy and Belgium, at two different scales. Firstly, we aimed to clarify the role of several eco-climatic factors on the regional-scale distribution of C. imicola in time, based on weekly samplings achieved throughout Italy from 2001 to 2006 and to develop an easy-to-use and reproducible tool, which could be widely validated on the basis of former vector sampling and freely accessible remote-sensing data. Secondly, we aimed to investigate how Culicoides species were distributed in the fine-scale habitat encountered throughout the agro-ecological landscapes of Belgium, while recent studies have suggested that the landscapes configuration could explain the spatial distribution of BT. In the first part, we showed that an autoregressive model where the observed monthly growth rate is predicted by monthly temperature, allowed predicting >70% of the seasonal variability in C. imicola trap catches. The model predicted the seasonality, the altitudinal gradient, and the low populations’ activity taking place during the winter. Incorporating eco-climatic indices such as the Normalized Difference Vegetation Index into the model did not enhance its predictive power. In the second part, we quantified how Culicoides populations are spatially structured in the neighbourhood of farms, and demonstrated the unexpectedly high level of population found in forest. We also showed how four classes of land use could influence the relative abundances of Culicoides species in the agro-ecological landscapes of Belgium. Although in summer, BT vectors were abundant in each of the four classes investigated, their relative abundances varied strongly as a function of sex, species and environmental conditions, and we quantified these variations. Finally, we also presented a new method to quantify the interference between Onderstepoort light traps, and used it to measure their range of attraction for several of the most common BT vectors species in Northern Europe. The model developed on C. imicola in Italy provided enthusiastic perspectives regarding the regional-scale analyses of its distribution in time, although further improvements are nevertheless required in order to assess the broad scale ecology of BT vectors throughout Europe. Mapping the abundances of C. imicola in Sardinia high- lighted an important lack of reliability attributable to the many land use classes that are currently not sampled in the vector surveillance achieved across Europe. Together with the novelties presented in the second part and the recent findings establishing that BT could circulate among wild hosts in both epidemiological systems (i.e. in Southern and Northern Europe), we call for increasing epidemiological and entomo- logical studies at the interface between farms and the surrounding natural habitats. Last, depicting in time the landscape-scale findings for Northern Europe highlighted how dramatic could be the role played by intensive farming practices to maintain BT within the agro-ecological landscapes studied and to facilitate its circulation between them. Quantifying the amplitude of the risk of disease transmission linked to these practices would require a further complex modeling approach accounting simultaneously for the diel activity of hosts, mainly resulting from the farming activities, the diel activities of different vector species and the landscapes configuration found in contrasted agro-ecological systems.Résumé :La fièvre catarrhale ovine (FCO), encore appelée maladie de la langue bleue, est une maladie infectieuse des ruminants transmise par la piqûre d’un vecteur de type moucheron appartenant au genre Culicoides (Diptera :Ceratopogonidae). L’ubiquité de ses vecteurs peut expliquer son succès d’installation à l’échelle globale. Par ailleurs, sa rapide expansion a été grandement facilitée par l’importante activité anthropique (élevage, transport, modification de l’habitat) et peut-être même par les changements climatiques globaux. La FCO a été récemment qualifiée de maladie infectieuse émergente en Europe du fait de (i) son récent établissement dans la région, bien au delà de son aire de répartition traditionnelle, (ii) de sa forte capacité de dispersion affectant chaque jour un nombre plus important d’hôtes et enfin (iii) de sa forte virulence. Après avoir détaillé les caractéristiques majeures des deux principaux foyers de FCO rencontrés en Europe depuis 1998, la présente thèse s’est plus particulièrement intéressée à l’étude de la distribution spatio-temporelle de ses principaux vecteurs dans le sud (partie 1) puis dans le nord (partie 2) de l’Europe, à différentes échelles. Dans la première partie, un modèle discret, spatialement et temporellement explicite, a été développé afin de mesurer l’influence de différents facteurs éco-climatiques sur la distribution de Culicoides imicola, principal vecteur de la FCO dans le Bassin Méditerranéen. Les profils mensuels de distribution rencontrés en Sardaigne durant 6 années consécutives ont ainsi pu être reconstitués, principalement sur base de la température. Une cartographie de l’abondance de C. imicola sur le territoire a permis de mettre à jour le manque d’information sur sa distribution en dehors des exploitations agricoles. Dans la deuxième partie du travail, nous nous sommes penchés sur la distribution spatiale des Culicoides tels qu’on peut les rencontrer au sein de différents paysages agro-écologiques de Belgique. Nous avons ainsi pu décrire la structure adoptée par les populations de Culicoides au voisinage des fermes ainsi que quantifier l’importante population présente dans les forêts avoisinantes. Nous avons par ailleurs montré l’influence de différentes catégories d’utilisation du sol sur l’abondance et la composition en espèces. Enfin, nous avons présenté une méthode permettant de quantifier l’interférence entre des pièges lumineux utilisés dans un même paysage pour échantillonner les populations, et l’avons utilisé afin de mesurer leur rayon d’attractivité sur les espèces vectrices les plus communément rencontrées dans le nord de l’Europe. En guise de conclusion générale et conjointement aux récentes découvertes de cas de FCO au sein de la faune sauvage européenne, nous appelons à réaliser un plus grand nombre d’études éco-épidémiologiques à l’interface entre exploitations agricoles et zones (semi-) naturelles avoisinantes. En outres, les résultats présentés dans la seconde partie ont été mis en relation avec le mode de fonctionnement journalier de nos exploitations agricoles. Nous avons ainsi pu déduire le rôle dramatique joué par les pratiques agricoles intensives dans le maintien du virus de la FCO au sein de nos paysages agro-écologiques, ainsi que dans sa circulation d’un paysage à l’autre. Un cadre de modélisation complexe permettant une analyse simultanée de l’activité nycthémérale des hôtes de la FCO et de ses vecteurs Culicoides en fonction de la configuration des paysages agro-écologiques est néanmoins requis afin de quantifier l’amplitude du risque de transmission de la FCO lié aux pratiques agricoles intensives.
Doctorat en Sciences agronomiques et ingénierie biologique
info:eu-repo/semantics/nonPublished
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Anselmo, GeÃrgia Carvalho. "Efeitos de extratos de plantas e de reagentes quÃmicos sobre Papaya lethal yellowing virus e sua movimentaÃÃo em mamoeiro." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=10487.
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FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgicoO mamoeiro (Carica papaya) à uma importante fruteira tropical e sua produÃÃo està aumentando no Nordeste Brasileiro. O Papaya lethal yellowing virus (PLYV) à encontrado infetando o mamoeiro somente no Nordeste brasileiro, aonde vem constituindo sÃrio problema para os produtores. O PLYV à bastante estÃvel e pode ser transmitido por inoculaÃÃo mecÃnica, solo, Ãgua de irrigaÃÃo, mÃos e instrumentos de corte contaminados. A presente atividade de pesquisa teve por objetivo avaliar os efeitos de produtos quÃmicos e de extratos de plantas de uso medicinal sobre a infectividade do PLYV; acompanhar a distribuiÃÃo do vÃrus em plantas inoculadas e avaliar sua interaÃÃo com o Papaya ringspot virus (PRSV). Extratos de plantas infetadas com PLYV foram misturados com igual volume de um dos seguintes produtos quÃmicos: Ãlcool, n-butanol, sabÃo lÃquido comercial, Triton X-100, sÃdio dodecilsulfato (SDS), hipoclorito de sÃdio e carbonato de sÃdio e com extratos de 23 espÃcies vegetais de uso medicinal. As misturas foram incubadas por 30 min em condiÃÃes de laboratÃrio e mecanicamente inoculadas em plantas de mamoeiro. Amostras iguais de tecidos de plantas inoculadas com PLYV foram avaliadas por ELISA indireto para determinar o tempo necessÃrio para sua infecÃÃo sistÃmica. De acordo com os resultados, somente SDS, hipoclorito de sÃdio e carbonato de sÃdio inativaram o vÃrus, mas o SDS ocasionou danos nas plantas e o carbonato ocasionou pequenas pontuaÃÃes esbranquiÃadas. De outra parte, nenhum dos extratos de plantas inativou completamente o PLYV, mas o extrato de Schinus terebinthifolius retardou os sintomas do vÃrus. Tais resultados demonstram a importÃncia do uso de soluÃÃes de hipoclorito de sÃdio para a inativaÃÃo do PLYV na superfÃcie de ferramentas agrÃcolas. Estudos da movimentaÃÃo do vÃrus em plantas inoculadas indicaram que a presenÃa do PLYV pode ser detectada por sorologia nas folhas inoculadas trÃs a quatro dias apÃs a inoculaÃÃo, seis dias no caule, 10 dias nas raÃzes, 15 dias nas folhas mais jovens e a planta inteira foi infetada sistemicamente somente apÃs 25 a 30 dias. Estudos de gama de hospedeiros confirmaram que o PLYV nÃo infeta espÃcies das famÃlias: Amaranthaceae, Brassicaceae, Fabaceae, Pedaliaceae e Solanaceae, nem ocasiona lesÃes locais nas indicadoras Chenopodium amaranticolor; C. murale e C. quinoa. Os estudos sobre a interaÃÃo entre PLYV e PRSV demonstraram a existÃncia de sinergismo entre os dois vÃrus em mamoeiro. A tÃcnica de imunoprecipitaÃÃo de RT-PCR (IP-RT-PCR) demonstrou ser um mÃtodo prÃtico e especÃfico para amplificaÃÃo do RNA do vÃrus, reduzindo problemas de contaminaÃÃo com o RNA de plantas.
Papaya (Carica papaya) is an important tropical fruit crop and its production is increasing every year in Northeastern Brazil. Papaya lethal yellowing virus (PLYV) is found infecting papaya only in Northeastern Brazil where it has become a serious problem for the papaya producers. PLYV is very stable and it can be readily transmitted by human actions including contaminated hands, agricultural tools, soil and irrigation water. The present study had the objective to evaluate the effects of chemical products and the extracts from 23 medicinal plants on the infectivity of PLYV in greenhouse experiments; to determine the distribution and movement of PLYV in mechanically inoculated plants and evaluate its interaction with Papaya ringspot virus (PRSV). Extracts from PLYV infected plants were mixed with equal amount of either one of the following chemical products: alcohol, n-butanol, commercial liquid soap, Triton X-100, sodium dodecilsulfate (SDS), sodium hypochlorite and sodium carbonate, and with equal amount of extracts from 23 medicinal plant species. The mixtures were incubated for 30 min at room temperature and mechanically inoculated in healthy papaya. Equal amounts of tissue from each part of papaya plants inoculated with PLYV were serologically evaluated to demonstrate how long the virus takes to infect systemically inoculated plants. According to the results only SDS, sodium hypochlorite and sodium carbonate inactivated the virus, but SDS caused damage in the plants and carbonate caused small whitish points on the treated leaves. On the other hand, neither one of the used medicinal plant extracts inactivated completely the PLYV infectivity, but extracts from Schinus terebinthifolius inhibited the symptoms induced by the virus. Those results demonstrated the importance of sodium hypochlorite to inactivate PLYV in contaminated agriculture tools. The presence of PLYV in inoculated plants was serologically detected three to four days after inoculation in the inoculated leaves, only after six days in the stem, ten days in the roots, 15 days in the younger leaves and the plants were systemically infected only 25 to 30 days after inoculation. Host range studies confirmed that PLYV does not infect plant species from the families: Amaranthaceae, Brassicaceae, Fabaceae, Pedaliaceae and Solanaceae, neither cause local lesions in Chenopodium amaranticolor; C. murale and C. quinoa. Interaction studies indicated a synergistic effect between PLYV and PRSV in papaya. The technique of RT-PCR immunoprecipitation (IP-RT-PCR) has proven to be practical and specific for amplification of PLYV RNA, reducing problems of contamination with plant RNAs.
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Yahyaoui, Emna. "Use of standard and setup of non conventional techniques for the elimination of viruses associated with Fig Mosaic Disease (FMD) in fig germplasm (Ficus carica L.)." Doctoral thesis, Universitat Politècnica de València, 2017. http://hdl.handle.net/10251/79876.
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Abstract
Ficus carica L. is considered one of the oldest fruit trees in the Mediterranean basin and is widely grown and harvested for the consumption of its fruits dry and fresh. This species is affected by different virus diseases, especially by Fig mosaic disease (FMD), for which Fig leaf mottle-associated virus 1 (FLMaV-1), Fig leaf mottle-associated virus 2 (FLMaV-2), Fig mild mottling-associated virus (FMMaV), Fig mosaic virus (FMV), Fig latent virus 1 (FLV-1), Fig badnavirus 1 (FBV-1) and Fig fleck-associated virus (FFkaV) are associated. FMD is the most widespread disorder of this species, which represents a threat and a constraint for healthy fig production and germplasm exchange.
Thus, the objective of the present doctoral research was the establishment of an efficient and rapid in vitro F. carica propagation, sanitation and conservation of free-FMD plant material for future large-scale commercialization.
Initially, FMD-related viruses distribution was screened within the different fig plant organs (buds, leaves, syconia and seeds) of 14 Mediterranean genotypes (Palazzo, Severoni precoce, Bianca, Pilusedda, Dottato bianco, Bifera, Zidi, Baiyadi, Biancu, Brogiotto nero, Catalanisca, Houmairi, Triboiti and Turca 'Serilop') which were utilized afterward as in vitro plant source material. RT-PCR assays revealed that all the aforementioned viruses were present without any exception in seeds, whereas only 4 viruses (FBV, FFkaV, FLMaV-1 and FMV) were detected in buds, leaves and syconia with highly variable infection rates.
Moreover, encapsulation technology proved to be a powerful multiplication technique to sustain standard fig tissue culture protocol for three cultivars (Catalanisca, Palazzo and Bifera) and it gave high, almost similar, viability, regrowth and conversion rates. Microcutting rooting in one-step was achieved and conversion rate was comparable for the three cultivars.
Furthermore, in order to eliminate FMD associated viruses, with the exception of FBV-1 which resisted to all the sanitation attempts, Caulogenesis and Meristem Tip Culture Protected by the Synthetic Seeds technique (MTC-SS) gave the best sanitation rates.
Finally, F. carica (cv. Houmairi) artificial seeds conservation, for final delivery, was achieved. A high viability and moderate regrowth rates were registered with a lesser conversion rate strictly related to the plant growth regulators (PGRs) used.
Keywords: Fig, mosaic, RT-PCR, virus distribution, cytokinins, encapsulation, micropropagation, synthetic seed.Resumen La higuera (Ficus carica L.) es considerada como uno de de los árboles frutales más antiguos de la cuenca mediterránea y es ampliamente cultivado y cosechado para el consumo de sus frutos tanto secos como en fresco. Esta especie se ve afectada por diversas enfermedades virales, especialmente por la denominada "Fig mosaic disease" (FMD) asociada actualemnte a los virus: Fig leaf mottle-associated virus 1 (FLMaV-1), Fig leaf mottle-associated virus 2 (FLMaV-2), Fig mild mottling-associated virus (FMMaV), Fig mosaic virus (FMV), Fig latent virus 1 (FLV-1), Fig badnavirus 1 (FBV-1) y Fig fleck-associated virus (FFkaV). Esta enfermedad representa una amenaza y un obstáculo para la producción de higos y el intercambio de germoplasma. El principal objetivo del presente trabajo fue establecer un método de propagación de higuera in vitro para el saneamiento y la conservación de material vegetal libre de FMD para su posterior comercialización. Inicialmente, se estudió la distribución de los virus implicados en la enfermedad en diversos órganos de 14 genotipos de F. carica (Palazzo, Severoni precoce, Bianca, Pilusedda, Dottato bianco, Bifera, Zidi, Baiyadi, Biancu, Brogiotto nero, Catalanisca, Houmairi, Triboiti y Turca 'Serilop'), los cuales fueron utilizados posteriormente como fuente material vegetal in vitro. Los resultados obtenidos mediante RT-PCR revelaron que todos los virus mencionados estaban presentes sin excepción en las semillas, mientras que sólo cuatro de ellos (FBV, FFkaV, FLMaV-1 y FMV) fueron en brotes, hojas y siconios con tasas de infección variables. Además, la tecnología de encapsulación demostró ser una técnica de multiplicación eficaz para poder aplicar el protocolo estándar de cultivo de tejidos de higo para tres cultivares (Catalanisca, Palazzo y Bifera) dando altas tasas de viabilidad, rebrote y conversión. Se logró el enraizamiento de microcortes en un solo paso y el índice de conversión fue comparable para los tres cultivares. La callogénesis y el culñtivo de meristemos con la técnica de la semilla sintética (MTC-SS) fueron las técnicas que proporcionaron mayores tasas de desinfección para los virus estudiados a excepción de con FBV-1, entidad viral que no fue eliminada con ninguna de las técnicas ensayadas. Por último, se logró la conservación de las semillas artificiales de higuera (cv Houmairi), registrándose una alta viabilidad y tasas de rebrote moderadas con un menor grado de conversión estrictamente relacionado con hormonas utilizadas. Palabras clave: Higuera, mosaico, RT-PCR, la distribución de los virus, hormonas, encapsulación, micropropagación, y la semilla sintética.
Resum La figuera (Ficus carica L.) és considerada un dels arbres fruiters més antics de la conca mediterrània i és àmpliament conreat i collit per al seu consum fresc i sec. Les malalties virals, especialment "Fig mosaic disease" (FMD), associada amb els viruses: Fig leaf mottle-associated virus 1 (FLMaV-1), Fig leaf mottle-associated virus 2 (FLMaV-2), Fig mild mottling-associated virus (FMMaV), Fig mosaic virus (FMV), Fig latent virus 1 (FLV-1), Fig badnavirus 1 (FBV-1) i Fig fleck-associated virus (FFkaV). Esta malaltia representa una amenaça per a la producció de figues i l'intercanvi de germoplasma. El principal objectiu d'aquest treball va ser estableixerun mètode de propagació de figuera in vitro per al sanejament i la conservació de material lliure de FMD per a su posterior commercialització. Inicialment, es va estudiar la distribució dels virus associats a FMD en diversos òrgans en 14 genotips de F. carica (Palazzo, Severoni Precoce, Bianca, Pilusedda, Dottato bianco, Bifera, Zidi, Baiyadi, Biancu, Brogiotto diners, Catalanisca, Houmairi, Triboiti i Turca 'Serilop'), els quals van ser utilitzats posteriorment com a font de material vegetal in vitro. Els resultats obtinguts del anàlisis realitzats per RT-PCR van revelar que tots els virus eren presents sense excepció en les llavors, mentre que només quatre virus (FBV, FFkaV, FLMaV-1 i FMV) van ser detectats en brots, fulles i siconis amb taxes d'infecció variables. A més, la tecnologia d'encapsulació va demostrar ser una tècnica de multiplicació eficaç per poder aplicar el protocol estàndard de cultiu de teixits de figa per a tres cultivars (Catalanisca, Palazzo i Bifera) donant taxesadequades de viabilitat, rebrot i conversió. Es va aconseguir l'arrelament de microtalls en un sol pas i l'índex de conversió va ser comparable per als tres cultivars. La calogènesi i el cultiu de meristems protegits per llavors sintètiques (MTC-SS)van ser les tècniques que proporcionarem millores tases de desinfecció per als virus estudiats amb l'excepció de FBV-1 que es va resistir a tots els mètodes de sanejament. Finalment, es va aconseguir la conservació de la llavors artificials de figuera (cv. Houmairi), registrant-ne una alta viabilitat i taxes de rebrot moderades amb un menor grau de conversió estrictament relacionat amb hormones utilitzades. Paraules clau: Figuera, mosaic, RT-PCR, la distribució dels virus, hormones, encapsulació, micropropagació, i la llavor sintètica.
Yahyaoui, E. (2017). Use of standard and setup of non conventional techniques for the elimination of viruses associated with Fig Mosaic Disease (FMD) in fig germplasm (Ficus carica L.) [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/79876
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Jordier, Edme. "Epidémiologie moléculaire du virus de l'hépatite C (VHC) chez les donneurs de sang français entre 2008 et 2011 : caractérisation de génomes complets du VHC appartenant au génotype 2." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM5095.
Full textAbstract:
La distribution des génotypes du virus de l’hépatite C (VHC). chez les donneurs de sang Français entre 2008 et 2011 a été analysée afin d’actualiser nos connaissances. Le génotypage des souches a permis d’identifier la diversité des génotypes circulants. Les sous-types 1a, 1b et 3a sont majoritairement retrouvés (80% des souches). L’analyse phylogénétique a démontré une grande variabilité chez les types 2 et 4 représentés par de nombreux sous-types. Les résultats montrent que les comportements à risque tendent à influencer et redessiner la distribution de ces génotypes dans la population générale. Certains sous-types se répandent dans des groupes à risque où ils finissent par adopter un profil épidémique. Enfin, la sélection des donneurs et la mise en place de tests diagnostiques ont permis de rendre la contamination transfusionnelle négligeable. Les données épidémiques obtenues ont été enrichies de nouvelles connaissances sur l'évolution et la classification du VHC. 15 séquences codantes complètes de plusieurs souches appartenant au type 2 ont été caractérisées. L’analyse phylogénétique révèle 2 clusters distincts. Le cluster 1 comprend la plupart des souches tandis que le cluster 2 comprend le sous-type 2l. Les génomes obtenus ont un ORF de 9042 à 9108 bases (3014 à 3036 acides aminés). Les distances moyennes entre sous- types sont égales à 20% dans le cluster 1 et 26% entre les deux clusters. La bifurcation entre clusters a eu lieu tôt lors de l'évolution du virus. L'insertion de 60 bases dans la région NS5A caractéristique du type 2 est absente chez les 2l. Donc, l'apparition et la fixation de celle-ci sont tardives dans l'évolution du virusThe distribution of genotypes of hepatitis C virus (HCV) infection among blood donors French between 2008 and 2011 was analyzed in order to update our knowledge. Genotyping strains identified the diversity of circulating genotypes. Subtypes 1a, 1b and 3a are found predominantly (80 % of strains). Phylogenetic analysis showed a great variability in types 2 and 4 represented by many subtypes. The results show that risk behaviors tend to influence and reshape the distribution of these genotypes in the general population. Some subtypes are spreading risk groups where they eventually adopt an epidemic profile. Finally, donor selection and implementation of diagnostic tests reduced drastically blood contamination. Epidemic data were enriched of new knowledge about the evolution and classification of HCV. 15 complete coding sequences of several strains of type 2 have been characterized. Phylogenetic analysis reveals two distinct clusters. Cluster 1 includes most strains while cluster 2 includes subtype 2l. Genomes obtained have an ORF of 9042 to 9108 bases (3014-3036 amino acids). The average distances between subtypes are equal to 20% in cluster 1 and 26 % between the two clusters. The bifurcation between clusters occurred early during the evolution of the virus. The insertion of 60 bases in the NS5A region characteristic of Type 2 is absent in 2l. So the appearance and fixing it is late in the evolution of the virus