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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
471

Diffusion d'un virus et évolution de son génome dans les populations de ruminants domestiques : application à l'épidémiosurveillance de la "Peste des petits ruminants" / Spread of virus and evolution of its genome in populations of domestic ruminants : Application to molecular epidemiology and surveillance of 'Peste des petits ruminants'

Salami, Habib 13 February 2015 (has links)
La peste des petits ruminants (PPR), causée par un Morbillivirus, est l'infection virale la plus grave des caprins et ovins. Elle est largement répandue en Asie, au Moyen Orient et en Afrique. En Afrique elle est en émergence au nord et au sud du continent et représente un facteur majeur d'insécurité alimentaire pour la population agricole (70% des populations pauvres des régions considérées). La PPR est un modèle d'étude des maladies transfrontalières ; sa diffusion est très liée aux mouvements régionaux d'animaux vivants. La compréhension de cette diffusion est une condition essentielle à la mise en place de mesures de contrôle efficaces (vaccination, quarantaine, contrôle aux frontières,…). A notre connaissance aucune étude n'a été entreprise pour connaître l'ampleur de la diversité génétique du PPRv au cours d'infections naturelles de petits ruminants et l'accumulation des mutations virales dans un circuit de diffusion. Or dans les pays d'élevages extensifs tropicaux l'identification et la traçabilité animale sont inexistantes, ce qui rend difficile reconstruction des circuits de diffusion des animaux et du virus. Dans ces conditions, la diversité génétique du virus peut être utilisée comme marqueur de diffusion épidémiologique. L'objectif de cette thèse est d'utiliser la variabilité génétique du PPRV pour caractériser les lignées virales circulantes et retracer les processus de transmission du virus à travers un large territoire centré sur le Sénégal. En analysant 2 gènes de PPR nous avons estimé la vitesse d'évolution du virus sur une période de 4 années comprise en 2010 et 2014.Les résultats montrent que les premières souches de la lignée 2 de PPRv ont été introduites en 2005 au Sénégal et dans les pays voisins. L'horloge moléculaire et l'arbre phylogéographique rapportés ici indiquent clairement que la lignée II maintenant enzootique en Afrique de l'ouest prend son origine au Nigeria. Les mouvements trans-africains à l'origine du déplacement est-ouest de la lignée II trouvent leur origine dans le commerce de bétail à la croisée des frontières, une évidence économique et culturelle en Afrique de l'Ouest.Mots clés : peste des petits ruminants ; gène viral ; mutation virale ; circuit de transmission ; phylogénie ; phylogéographie ; surveillance épidémiologique, Sénégal. / Peste des petits ruminants (PPR), caused by a Morbillivirus is one of the most important viral infections in sheep and goats. It is widely spread in Asia, Middle East and Africa. In Africa, it is an emerging disease in the north and the south of the continent. It is a major factor of food insecurity for the farming population (70% of the poor population in the tropical regions). PPR is a study model of transboundary diseases; its spread is highly related to regional movements of livestock. Understanding the spread of PPR is an essential condition for the implementation of efficient control measures (vaccination, quarantine, border controls etc.). Up to our knowledge, no studies have investigated the range of genetic diversity of PPR virus (PPRv) during natural infections in small ruminants and the accumulation of virus mutations during its spread. Further on, in tropical countries with extensive farming, animal identification and traceability are a current problem. In such conditions, the genetic diversity of the PPRv can be used as a marker of animal movement and spread of the virus. The objective of this study was to investigate the genetic diversity of the PPRv in order to characterise the actual viral lineages and to retrace the transmission of the virus in Senegal and its surrounding countries. Analyzing two complete viral genes of the PPR, we have estimated the rate of evolution of this virus, in a four year period, between 2010 and 2014. The results of the study show that the first strains of lineage II of PPRv have been introduced in 2005 in Senegal and its surrounding countries. Molecular clock analysis and phylogeographical reconstitution of the PPRv indicate that the lineage II, actually enzootique in western Africa, has its origins in Nigeria. This viral introduction from the direction east towards west, corresponds to the transboundary movement and commerce of livestock in the countries of western Africa, which represents the economic and cultural tradition of the people of this region.Key words: Peste des petits ruminants, viral gene, virus mutation, transmission, phylogeny, phylogéographie, epidemiosurveillance, Senegal, West Africa
472

Cinomose Canina : detecção do RNA viral pela reação em cadeia pela polimerase (RT-PCR) em cães com diagnóstico clínico da doença. / Canine distemper vírus : detection of viral RNA by RT-PCR in dogs with clinical diagnosis.

Rosana Alcalde 08 December 1999 (has links)
O vírus da cinomose canina (VCC) é um patógeno viral, altamente, contagioso que pode causar doença sistémica letal, em cães e outros carnívoros em toda parte do mundo. Os cães afetados podem apresentar sintomas gastrentéricos, respitatórios e nervosos. As manifestações clínicas da doença inclue depressão, diarréia, vómito, desidratação, hiperqueratose dos coxins e focinho e espasmos musculares ou paresia de membros pélvicos, a qual pode persistir por longos períodos. Cães infectados, com sintomas clínicos de VCC, foram estudados para detecção do RNA viral pela técnica de PCR e Nested-PCR. Neste estudo, amplificou-se o gene da nucleoproteína (NP) em células mononucleares do sangue periférico (linfócitos), urina e saliva, de cães infectados com VCC, para detectar o genoma do mesmo, por RT-PCR, em diferentes amostras clínicas. A identificação do RNA viral foi concluída com sucesso, pelo método de RT-PCR, utilizando 2 pares de \"primers\" específicos do gene da nucleoproteína (NP). A técnica de RT-PCR, descrita neste etudo, pode ser um sistema de ensaio útil para determinar se cães suspeitos de infecção, por VCC, tenha níveis detectáveis de genes. Os resultados demonstram que a técnica de RT-PCR é exequível para o diagnóstico laboratorial de cinomose canina. / Canine distemper vírus (CDV) is a highly contagious Viral pathogen which may cause lethal systemic in dogs and other carnivores throughout the world. Affected dogs show gastrointestinal and respiratory clinical slgns, and frequently develop clinical signs in the central nervous system (CNS). Clinical manifestations of the disease include depression, progressive loss of weight, dehydration, hyperkeratosis of the foot pads and nose, nervous symptoms and muscular spasms or posterior paralysis which may perslst for long periods. Infected dogs with clinical symptoms for CDV, were by detection of viral RNA by Polymerase Chaln Reaction (PCR) and Nested PCR. In this study,w e determinebdy the RT-PCRth e presenceo f nucleoprotein (NP) gene in peripheral blood mononuclear cells, urine and saliva from dogs infected with CDV. The goals of this study was to detect CDV renome by RT-PCR in different clinical samples. In this study, Identificatlon of NP mRNA was successfully achieved by using the RT-PCR method with two sets of NP gene specific primers. The RT-PCR technique described in thls study, may provide a useful assay system to determine whether the dogs suspected of CDV infection have detectable leveis of CDV genes. The results demonstrate that RT-PCR technique is rapid, sensitivity and specificity for vírus diagnosis.
473

Viral Marketing : A Quantitative Study about how Viral Marketing affects the Consumers Buying Act

Gholamzadeh, Caroline, Jakobsson, Karolina January 2011 (has links)
No description available.
474

Epidemiologia das meningites bacterianas e virais agudas ocorridas no Instituto Estadual de infectologia Säo Sebastiäo (IEISS) - Rio de Janeiro - Período 11.11.96 a 10.06.97 / Epidemiology of the bacterial and viral acute meningitis occurred in the Instituto Estadual de Infectologia Säo Sebastiäo (IEISS) - Rio de Janeiro

Trócoli, Maria Graziela Cavalcanti January 1998 (has links)
Made available in DSpace on 2012-09-06T01:11:04Z (GMT). No. of bitstreams: 2 license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) 99.pdf: 2691977 bytes, checksum: 3fa2eff2b005ba0c1d8204b7a0ffaf2c (MD5) Previous issue date: 1998 / Descreve um estudo de Coorte Descritivo Retrospectivo, realizado com dados obtidos através de prontuários de pacientes internados no Instituto Estadual de Infectologia Säo Sebastiäo, no período de 11/96 a 06/97, que tiveram diagnóstico definitivo de meningite bacteriana ou viral. Procedeu-se às estimativas das gravidade e letalidade, de ambas as meningites, comparando-as entre si, bem como dos respectivos agentes etiológicos específicos. Com base nos 204 pacientes, 141 dos quais, portadores de meningite bacteriana e 63, de meningite viral, viu-se que as primeiras se apresentaram mais graves e mais letais que estas últimas, com excessos de risco de 17,6 e 7,8 por cento, respectivamente. Também evidenciou-se que, apesar de todas as infecçöes bacterianas apresentarem casos graves e incidência de óbitos, a que teve maior número destes desfechos foi a meningite pneumocócica, enquanto que, dentre as virais, a meningite por Herpes simples vírus, foi a única a apresentar tais eventos. Os maiores preditores para a gravidade foram a meningite pneumocócica, a meningite por Herpes simples vírus e a idade de 15 anos ou mais. Já para a letalidade, os preditores, além destes patógenos, foram os menores de 1 ano e evoluçäo clínica para o coma, na meningite bacteriana, e a idade de 15 anos ou mais e evoluçäo para torpor ou coma na viral. Ainda constatou-se que as características liquóricas seguem um padräo bem definido para cada uma das meningites em estudo. / This is a Retrospective Descriptive Cohort study, accomplished through reference book, with patients interned at the São Sebastião State Institute of Infectology, in Rio de Janeiro City, Brazil, in the period from 11/96 to 06/97, with definitive diagnosis of bacterial or viral meningitis. It was proceeded to the estimates of the severity and mortality, of both meningitis, comparing them to each other, as well as the respective pathogens. Based on the 204 patients, 141 of the which, carriers of bacterial meningitis and 63, of viral meningitis, the first ones came more severe and more lethal than these last ones, with excesses of risk of 17,6 and 7,8%, respectively. It was also evidenced that, in spite of all the bacterial infections they present severe cases and obits incidence, the one that had larger number of these was the pneumococcal meningitis, while, of the viral ones, the meningitis for Herpes simplex virus, was the only to present such events. The most importants predictores for the severity were pneumococcal meningitis, herpes simplex virus meningitis and the 15 years-old age or more. Already for the mortality, the predictores, besides these pathogens, was last then 1 year old and clinical evolution for the coma, in the bacterial meningitis, and the 15 years-old age or more and evolution for torpor or coma, in the viral one. It was still verified that the cerebrospinal fluid (CSF) characteristic follows a pattern very defined for each one of the meningitis in study.
475

Enterovirus Non-structural Protein 3A Interactions with Sec12, an upstream Component of the COPII Secretory Pathway and Implications for Viral Replication

Nanda Kishore, R January 2015 (has links) (PDF)
Polioviruses, Coxsackieviruses, and Echoviruses belonging to the Picornaviridae family of positive-stranded, non-enveloped viruses, are highly infectious and associated with a range of illnesses in children from minor febrile illness to severe, potentially fatal conditions (eg, aseptic meningitis, encephalitis, paralysis and myocarditis). The viruses encodes 11 viral proteins along with the transient set of intermediates unique to viral propagation. 3A, one of the non-structural proteins, plays a crucial role in viral replication by anchoring the replication complex to the membrane vesicle and by recruiting essential cellular factors to the site of replication. It is an 89 amino-acid longprotein, and consists of a soluble N-terminal region and a hydrophobicC-terminal region. The soluble region contains two amphipathic alphahelices that form a hairpin, which are flanked by unstructured regions.Since, Enteroviruses have limited coding capacity,viral protein interactions with cellular proteins and lipids are essentialin viral replication, translation, polyprotein processing andpathogenesis. Understanding these interactions is essential inunderstanding the molecular mechanisms associated pathogenesis, andidentifying drug targets. Our studies are aimed at identifying hostfactors interacting with 3A protein and their functional significance invirus replication.We have identified thepotential 3A-interacting cellular candidate proteins using pull-down followed by liquid chromatography associated mass spectrometry. Gene ontology analysis revealed asignificant enrichment in cellular pathways, functions, and proteindomains in comparison with the control. Further studies were focused on Sec12 (guanine nucleotideexchange factor), ACBD3 (acyl-CoA binding domain containing 3) andPhosphatidylinositol 4-kinase beta (PI4KIIIß) interactions with the 3Aprotein, and their significance in viral replication. Sec12 (GEF) initiates the COPII vesicle-mediated ER-to-Golgi membrane trafficking by recruiting and activating the small GTP binding protein Sar1A to the membrane, which further recruits Sec23/24, cargo and Sec13/31 coat proteins to form functional COPII vesicles.We demonstrated that Sec12 and 3A interact directly in the ER through their C-terminal hydrophobic regions in oligomerization independent manner, leading toreduced the level of recruitment of individual COPII components such as Sar1A, Sec24A, and Sec31A to the membranes, thereby inhibiting virus replication. But in infected cells, other viral proteins such as 2B and 2BC likely stabilize the membrane-recruited Sar1A to support the viral replication. The viral proteins, ACBD3, PI4KIIIß interacted and co-localized with the Echovirus 3A protein.Knockdown of Sec12 or PI4KIIIß and expression of 3A or DN-Sar1A inhibited Echovirus replication, unlike proteins which support the COPII vesicle mediated ER-to-Golgi trafficking.Our results collectively indicate Sec12 is a crucial component in the anterograde membrane trafficking and is a novel host factor in Echovirus replication.
476

Structure and Dynamics of Viral Substrate Recognition and Drug Resistance: A Dissertation

Ozen, Aysegul 29 May 2013 (has links)
Drug resistance is a major problem in quickly evolving diseases, including the human immunodeficiency (HIV) and hepatitis C viral (HCV) infections. The viral proteases (HIV protease and HCV NS3/4A protease) are primary drug targets. At the molecular level, drug resistance reflects a subtle change in the balance of molecular recognition; the drug resistant protease variants are no longer effectively inhibited by the competitive drug molecules but can process the natural substrates with enough efficiency for viral survival. Therefore, the inhibitors that better mimic the natural substrate binding features should result in more robust inhibitors with flat drug resistance profiles. The native substrates adopt a consensus volume when bound to the enzyme, the substrate envelope. The most severe resistance mutations occur at protease residues that are contacted by the inhibitors outside the substrate envelope. To guide the design of robust inhibitors, we investigate the shared and varied properties of substrates with the protein dynamics taken into account to define the dynamic substrate envelope of both viral proteases. The NS3/4A dynamic substrate envelope is compared with inhibitors to detect the structural and dynamic basis of resistance mutation patterns. Comparative analyses of substrates and inhibitors result in a solid list of structural and dynamic features of substrates that are not shared by inhibitors. This study can help guiding the development of novel inhibitors by paying attention to the subtle differences between the binding properties of substrates versus inhibitors.
477

Attityder vid viral marknadsföring på Facebook

Lindborg, Emilia, Berggren, Hanna January 2020 (has links)
Studien syftar till att undersöka och kartlägga vilka attityder de demografiska grupperna (Kvinnor 20-30, Män 20-30, Kvinnor 35-55 och Män 35-55) har gentemot rörliga virala kampanjer inom svenska livsmedelsbranschen. Vidare syftar studien till att se vilka slags rörliga virala kampanjer som sprids och varför inom de valda demografiska grupperna. Avslutningsvis undersöker studien vilken påverkan passiva och aktiva rörliga virala kampanjer har på attityden och spridningen hos de demografiska grupperna.För att besvara studiens frågeställningar har tre metoder valts ut för att utvinna relevant material. Först utfördes en litteraturgranskning för att kartlägga tidigare forskning, vidare utfördes huvudmetoden bestående av fyra fokusgrupper som var indelade utifrån deras demografi (6 stycken kvinnor 20-30 år, 6 stycken män 20-30 år, 6 stycken kvinnor 35-55 år och 6 stycken män 35-55 år). Avslutningsvis utfördes en analys av den insamlade datan som baseras på att skapa övergripande och meningsbärande kategorier utifrån antaganden som nämnts i datainsamlingen. De slutgiltiga meningsbärande kategorierna blev Attityder, Spridning samt Passiva/Aktiva budskap.Med utgångspunkt i studiens resultat- och diskussionsdel framgår det att relaterbar humor är den starkaste faktorn till att något sprid för alla studiens demografiska grupper. Väldigt lite spridning sker över Facebook när det gäller svenska livsmedelsbranschens kampanjer och för att öka denna måste den tidigare nämnda faktorn tas i beaktning mer än vad den gör idag anser alla demografiska grupper. Studiens demografiska grupper föredrar både passiva och aktiva kampanjer så länge de presenteras på ett humoristiskt sätt. Yngre män gillar dock även kontroversiell reklam, denna åsikt delade dock ingen annan demografisk grupp. / The study aims to investigate and identify the attitudes of the demographic groups (Women 20-30, Men 20-30, Women 35-55 and Men 35-55) towards viral campaigns in the Swedish food industry. Furthermore, the study aims to see what kinds of viral campaigns are being spread and why within the selected demographic groups. Finally, the study examines the influence of passive and active viral campaigns on attitudes and spread within the demographic groups.To answer the study's questions, three methods have been selected to extract relevant material. Firstly, a literature review was conducted to survey past research. Secondly, the main method consisted of four focus groups that were divided based on their demographics (Women 20-30, Men 20-30, Women 35-55 and Men 35-55). Finally, an analysis of the collected data was performed, which is based on creating overall and meaningful categories based on assumptions mentioned in the data collection. The final categories were Attitudes, Spread and Passive / Active messages.Based on the results and the discussion part of the study, it appears that relatable humor is the strongest factor when it comes to spreading a campaign in any of the study's demographic groups. Very little is being spread across Facebook regarding the Swedish food industry's campaigns and to increase this, the factor that is earlier mentioned must be taken into account more than it does today, according to all demographic groups in the study. The study's demographic groups prefer both passive and active campaigns as long as they are presented in a humorous way. Younger men however, also prefer controversial advertising, this opinion was however not shared with the rest of the demographic groups.
478

Inhibition of Newcastle disease virus infection of chicken embryo cells by caffeine

Olson, Norma. January 1978 (has links)
Call number: LD2668 .T4 1978 O43 / Master of Science
479

Innate host responses to Bovine Viral Diarrhea Virus

2016 February 1900 (has links)
Bovine viral diarrhea virus (BVDV) is a pestivirus that suppresses the innate and adaptive host immune responses. Each of the two classified genotypes (BVDV1 and BVDV2) has two distinct biotypes – cytopathic (cp) and non-cytopathic (ncp) – and evidence has suggested that cytopathic strains may disrupt host interferon (IFN) synthesis and IFN-mediated responses. However, inconsistent results examining ncpBVDV strains have generated controversy regarding whether they also exhibit this capability. The purpose for this study was to determine the occurrence and functionality of IFN-induced responses within the serum cattle infected with ncpBVDV2-1373. Specifically, this involved analysing the changes in both the serum levels of IFN-α and IFN-γ and the expression of genes that are classically regulated by these cytokines. Serum analysis showed that the infected cattle induced both serum IFN-α and IFN-γ during BVDV infection while PBMC analysis showed increased expression of genes that classically respond to IFN-α – Mx-1, OAS-1, and STAT-1 – and IFN-γ – SOCS-1 and SOCS-3. These findings are supported by temporal kinome analysis, which verified activation of the JAK-STAT signalling network within the PBMCs of the virus-infected animals. In addition to establishing evidence for its synthesis, results from this challenge identified IFN-γ as a possible indicator of animal mortality as analysis of its change within the non-surviving, infected animals was statistically greater than the levels of the surviving, infected animals. Collectively, these results demonstrate 1373-mediated induction of, and host cell response to, both IFN-α and IFN–γ, and the potential for IFN-γ to be a predictive marker for mortality during BVDV infection.
480

Management of bovine viral diarrhea virus in beef herds

Nickell, Jason S. January 1900 (has links)
Doctor of Philosophy / Department of Diagnostic Medicine/Pathobiology / Robert L. Larson / Bradley J. White / Bovine viral diarrhea virus (BVDV) is an endemic pathogen in the U.S. cow herd. The virus can cross the placental barrier and infect the unborn fetus. If infection occurs between 45 – 125 days of gestation, persistent infection (PI) in the unborn fetus is likely. Upon parturition, the PI calf is a lifelong shedder of BVDV significantly elevating the risk of viral exposure to non-PI cattle. Despite reports of significant production loss, many BVDV infections are subclinical and in some cases inconsequential. Our data has highlighted various factors potentially causing disparity in clinical outcomes following BVDV exposure including: variation of BVDV serum concentration among PI cattle which may influence the quantity of virus shed into the environment, preexisting BVDV immune (i.e. antibody) status among non-PI cattle, and the degree of stress experienced by non-PI cattle all may influence the susceptibility of disease. Additionally, cattle transiently infected (TI) with BVDV may temporarily shed BVDV thereby offering another source of exposure to non-PI cattle. Programs focusing on BVDV control and prevention consist of diagnostic tests to identify PI cattle, BVDV vaccines to reduce fetal infection and increase herd immunity, and biosecurity programs intended to prevent BVDV exposure to the resident herd. Survey work performed in Montana suggest that educating beef producers with regard to BVDV has significantly increased the implementation of these tools in order to reduce the risk of introducing BVDV to their resident herd. Despite the risk of production loss, the economic benefit of instituting whole-herd BVDV tests may vary due to herd prevalence. By utilizing Monte Carlo simulation, the current BVDV herd prevalence within the U.S. does not economically justify a nationwide BVDV eradication campaign. However, known BVDV positive herds and herds with an elevated likelihood (47%) of being BVDV positive displayed a positive economic outcome when whole-herd BVDV testing strategies were implemented across herd sizes of 50, 100, and 500 cows. The value of testing various testing modalities was dependent upon herd prevalence and herd size. These data suggest that veterinarians must critically evaluate the value of implementing whole herd testing protocols in U.S. beef herds.

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