Thesis (Ph. D.)--University of Wisconsin--Madison, 1966. / Vita. Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

L'incidence des infections à arbovirus (arthropod born virus) a augmenté de façon spectaculaire au cours des dernières décennies dans les régions tropicales et subtropicales du globe. Les virus de la dengue et du chikungunya sont transmis par les moustiques du genre Aedes et peuvent causer un large panel de symptômes, allant parfois jusqu’au décès. Bien que les tests de diagnostic conventionnels fournissent un diagnostic, l'accès à ces tests est limité dans les pays en développement. Un diagnostic précoce et rapide est crucial pour améliorer la prise en charge du patient. Il y a un besoin urgent de développer des outils peu chers, simples d’utilisation, rapides, et utilisables auprès du patient.Un PAD imprimé à la cire a été développé et évalué pour la détection de la protéine Non Structurale 1 (NS1) de la dengue, dans du sang et du plasma. Le PAD a été en mesure de détecter spécifiquement 10 ng.mL-1 de protéines dans divers types d'échantillons, en 6 à 8 minutes. Par la suite, une version améliorée du PAD obtenue par découpe laser a été conçue et testée pour la détection de la protéine NS1 de la dengue et des IgM spécifiques du virus, dans le sang et le plasma. Ces deux paramètres ont pu être détectés en 8 minutes. Les travaux de mise au point du PAD effectués sur la dengue ont ensuite été appliqués à la détection des IgM du virus du chikungunya dans des sérums humains, en utilisant des Particules virales Pseudotypées (PPs). Les résultats obtenus ont montré une sensibilité de 70,6% et une spécificité d'environ 98%. Le PAD a montré peu de réactions croisées avec d'autres arboviroses. Les PPs ont enfin été caractérisées par différentes méthodes physico-chimiques. / The incidence of arboviruses infections has increased dramatically in recent decades in tropical and sub-tropical areas worldwide. Dengue and chikungunya viruses are typically transmitted by mosquitoes and can cause a wide range of symptoms, and sometimes death. Although conventional diagnostic tests can provide diagnosis of acute infections, access to these tests is often limited in developing countries. Early and prompt diagnosis is crucial to improve patient management. Consequently, there is an urgent need to develop affordable, simple, rapid, and robust tools that can be used at ‘Point of Care’ settings.We developed and evaluated a PAD for the detection of the dengue Non Structural 1 (NS1) viral protein in blood and plasma samples. The PAD was able to detect specifically 10 ng.mL-1 of NS1 protein in various sample types and in 6-8 minutes. Secondly, an improved version of the PAD obtained by laser cutting was designed and tested for the detection of dengue NS1 protein and virus-specific IgM in blood and plasma. Each parameter could be detected in 8 minutes. PAD development performed on dengue fever was then applied to the detection of chikungunya virus IgM in human sera, using viral Pseudo-Particles (PPs). These synthetic antigens have proven to be powerful tools for specific IgM detection. The results obtained showed a sensitivity of 70.6% and a specificity of approximately 98% with a time to results of less than 10 minutes. The PAD showed few cross reactions with other arbovirusess. The PPS were finally characterized with different physico-chemical methods in order to determine the key factors of their performances.

Thesis (M.S.)--University of Wisconsin--Madison, 1970. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1970. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

L’émergence de certains arbovirus pathogènes pose un problème majeur en termes de santé public. Le virus Chikungunya (CHIKV) est un exemple de virus émergent car il s’est récemment adapté à un nouveau vecteur et cause des épidémies explosives. Cette émergence est en partie la conséquence de phénomènes liés à la grande plasticité génomique du CHIKV. Mieux comprendre les mécanismes d’adaptation des arbovirus pourrait permettre de mieux contrôler ces pathogènes viraux. La première partie de cette thèse porte sur l’étude des mutations associées à l’évolution à long terme du CHIKV sur différentes lignées de mammifères et de moustiques. Les résultats montrent des profils d’évolution distincts sur cellules de mammifères ou de moustiques, illustrant les difficultés liées à l’alternance d’hôte au cours du cycle naturel du CHIKV. La deuxième partie porte sur l’étude chez le CHIKV de la recombinaison génétique, un mécanisme fondamental pour l’évolution des virus à ARN. Les résultats montrent une absence de recombinaison homologue entre virus non défectifs, mais ces expériences ont permis de mettre en évidence la présence de virus délétés qui semblent aider par trans-complémentation la réplication d’un virus atténué. La dernière partie de cette thèse porte sur l’étude de méthodes de génétique inverse qui permettent de générer des virus et d’étudier les mutations associées à l’émergence de certains arbovirus. En utilisant le CHIKV comme modèle, nous avons étudié l’impact qu’ont certaines méthodes sur le génotype et le phénotype du virus in-cellulo et in-vivo chez le moustique. Les résultats montrent une stabilité du phénotype alors que le génotype viral dépend de la méthode utilisée. / Emergence of some pathogenic arboviruses is a major public health concern. The Chikungunya virus (CHIKV) is a typical example of re-emerging pathogen since it recently caused large outbreaks in human population, adapted to a new vector and spread to new areas. This emergence is the consequence of phenomena related to the high genomic plasticity of CHIKV. Understanding the mechanisms of adaptation of arboviruses could help to better control these viral pathogens. The first part of this thesis presents a study of the mutations associated with long-term replication of CHIKV in mammalian and mosquito cells. Our results revealed different evolutionary patterns in mammalian and mosquito cells highlighting the difficulties encountered by arboviruses related to host alternation during their natural cycle. The second part of this thesis deals with the homologous recombination, an important process that play a role in the evolution of RNA viruses. Working with the CHIKV, we did not detect any recombination events between attenuated infectious viruses. However, we detected viruses harboring large genomic deletion that could help an attenuated virus by trans-complementation. The last part of this thesis focused on reverse genetic methods that give the possibility to rescue viruses and can be used to study mutations associated with emergence phenomena. Using the CHIKV as a model, we compared the genotype and the phenotype of viruses generated using different reverse genetic methods in cellulo and in vivo using Aedes mosquitos. Our results showed that the choice of the method influenced the genetic diversity of viral populations but whatever the method used, the phenotype was similar.

Some viruses which infect plants, animals and man are transmitted by an intermediary arthropod vector. The viruses for which this is true are termed arboviruses (Arthropod-borne-viruses). In many instances the virus delivered to the new host results in the establishment of a disease state and/or the death of the infected host. In all instances, however, the arthropod (invertebrate) vector is apparently unaffected by the virus it is carrying. One family of viruses which are transmitted to their vertebrate host via an arthropod vector is the virus family Bunyaviridae, in this dissertation specifically the viruses Inkoo and Uukuneimi are described. The characteristics of Inkoo and Uukuneimi growth in both vertebrate baby hamster kidney (BHK-21, WI2) and invertebrate Aedes albopictus (mosquito) cell cultures has been examined. Vertebrate cells supported, to a high titer, the growth of both Inkoo and Uukuneimi virus while Aedes albopictus cell cultures supported high titer growth of Inkoo but not Uukuneimi. In both cases, however, the vertebrate cells were killed as a cosequence of infection where as, the invertebrate infection did not result in cell death or in detectable cytopathic effect. The invertebrate cells infected with either Inkoo or Uukuneimi continue to grow and also continue to express virus specific (actinomycin D resistent) RNA synthesis. The virus infected invertebrate cells are characterized as being persistently infected because of their resistence to homologous virus superinfection and by detectable virus specific RNA synthesis. Virus released from the Inkoo persistently infected cells displays a heterogeneous plaque morphology as well as temperature sensitive virus plaque mutants. Virus particles released from the Inkoo persistently infected Aedes albopictus cells are considered defective interfering-like. The RNA profile both intracellularly and of released virus particles from the persistently infected cell cultures is different from that observed during vertebrate cell culture infections. Cell death resulted from infection of BHK-21 WI2 cells with virus from Inkoo persistently infected Aedes albopictus cell cultures. The virus plaque morphology and RNA profile is similar to standard virus infection of BHK-21 WI2 cells. The experiments with tissue culture virus-cell systems aids in understanding the natural transmission of arboviruses between the vertebrate-invertebrate portions of the arbovirus natural life-cycle.

Thesis (Ph. D.)--University of Queensland, 2002. / Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1967. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1966. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis--University of Wisconsin--Madison. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 132-152).