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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.
21

Emerging and reemerging arboviruses: A new threat in Eastern Peru

Alva-Urcia, Carlos, Aguilar-Luis, Miguel Angel, Palomares-Reyes, Carlos, Silva-Caso, Wilmer, Suarez-Ognio, Luis, Weilg, Pablo, Manrique, Carlos, Vasquez-Achaya, Fernando, del Valle, Luis J., del Valle-Mendoza, Juana 14 November 2017 (has links)
Background Arboviral diseases are one of the most common causes of acute febrile illness (AFI) and a significant health problem in South America. In Peru, laboratory etiologic identification of these infections occurs in less than 50% of cases, leading to underdiagnoses of important emerging arboviruses. Aim To assess the prevalence of the Dengue (DENV), Oropouche (OROV), Chikungunya (CHIKV), Mayaro (MAYV) and Zika (ZIKV) viruses in patients with acute febrile illness from Puerto Maldonado (Peru). Methodology Serum samples were obtained from patients with AFI during January 2016 to March 2016. A total of 139 specimens were analyzed for the presence of DENV, OROV, CHIKV, MAYV, and ZIKV using polymerase chain reaction (PCR). Results CHIKV in 9.4% and OROV in 8.6% were the most prevalent arboviruses, followed by DENV and ZIKV, with a prevalence of 6.5% and 5%, respectively. Among all patients, the most common symptoms accompanying fever were headaches 79.9%, muscle pain 65.5% and joint pain 63.3%. Conclusions During this short 3-month period, 4 arboviruses were detected by PCR, CHIKV and OROV being the most common arboviruses in Puerto Maldonado (Peru). Thus, it is crucial to include OROV detection in the national health surveillance. Furthermore, the etiologic clinical diagnosis of arboviral infections is not possible due to the low specificity of symptoms; therefore an increase of cases confirmed by molecular diagnostic methods will enhance arboviral surveillance in Peru.
22

Etiologie virale des syndromes fébriles : recherche, identification et caractérisation des arbovirus circulant au Gabon / Viral etiology of febrile syndromes : research, identification and characterization of arboviruses circulating in Gabon

Caron, Mélanie 28 November 2013 (has links)
Depuis 2007, le Gabon est régulièrement confronté à des infections par les virus Chikungunya (CHIKV) et Dengue (DENV). Au total, près de 4300 prélèvements provenant de patients se présentant avec un syndrome fébrile algique, en phase clinique aiguë, ont pu être collectés et analysés pour la période de 2007 à 2010. En effet, deux importantes épidémies concomitantes de CHIKV et de DENV ont sévi au Gabon (i.e. Libreville en 2007 et Franceville en 2010). Entre ces deux flambées épidémiques, de nombreux cas sporadiques d'infection à CHIKV ou à DENV ont continué à être enregistrés à travers le pays. Des cas de co-infection à CHIKV/DENV ont également été diagnostiqués lors des deux flambées épidémiques. Ces deux arbovirus se sont ainsi propagés en quelques années dans un mouvement de nord-ouest à sud-est à travers le pays. L’étude plus avancée des cas de co-infection à CHIKV/DENV a pu démontrer que ce phénomène pouvait survenir soit de manière simultanée soit séquentielle au cours du repas sanguin d'Aedes albopictus, principal vecteur du CHIKV et du DENV au Gabon.(…)En conclusion, ce travail de thèse décrit précisément la survenue brutale d’épidémies imputables à plusieurs arbovirus circulant simultanément au Gabon et responsables de nombreux cas cliniques se présentant sous la forme d'un syndrome fébrile algique. La co-circulation de ces virus suggère l’apparition d’une dynamique de type épidémique/endémique et implique un problème de santé publique latent dans cette région d’Afrique, voire dans l’ensemble de la sous-région d’Afrique Centrale. / Following to the first simultaneous Chikungunya (CHIKV) and Dengue (DENV) viruses outbreak in 2007, an active surveillance of febrile syndromes was set up in Gabon, a central African country. During a three-year period, we observed a rapid spread of CHIKV and DENV in a southward movement from north-west to south-east of the country. Indeed, CHIKV and DENV have disseminated within a non-immune population, widely favored by the extraordinary capacity of Aedes albopictus vector to colonize diverse environments and to replace local mosquito’s species. In 2010, a second outbreak occurred in Gabon with further CHIKV/DENV co-infections in both human and mosquito. This is the first documented evidence of co-infection in a wild-caught Aedes albopictus. Additionally, an underlying Zika (ZIKV) virus epidemic transmission by the same invasive vector was retrospectively recorded during the outbreak in 2007. These data reveal an unusual ZIKV natural life cycle, occurring in an urban environment and potentially representing a new arboviral emerging threat from Aedes albopictus.(…)In conclusion, these data highlighted the recent introduction and rapid dissemination of CHIKV and DENV in Gabon. The Aedes albopictus vector has shown its extraordinary capacity to sustain epidemic transmissions, leading to arboviral co-circulations (i.e. CHIKV, DENV-2, DENV-1, DENV-3, ZIKV) and notably to some CHIKV/DENV-2 co-infection cases. This multiple arboviral circulation suggests an epidemic/endemic dynamic in Gabon, involving a latent public health problem in this region of Africa.
23

Diversité chimique et potentialités antivirales d'Euphorbiacées tropicales / Chemical diversity and antiviral potential of tropical Euphorbiaceae

Remy, Simon 23 October 2019 (has links)
Dans le but d'identifier de nouveaux inhibiteurs du chikungunya (CHIKV), de la dengue (DENV) et de la zika (ZIKV), une étude systématique portant sur 339 extraits d'Euphorbiaceae tropicales a été réalisée grâce à un test cellulaire d'inhibition du CHIKV et à des tests d'inhibition de l'ARN-polymérase de DENV et ZIKV.Sandwithia guyanensis et Sagotia racemosa, deux espèces provenant de Guyane française, dont les extraits d'écorce présentaient une forte activité anti-CHIKV importante, ont d'abord été étudiées. À la suite d'un processus d'isolement bioguidé classique, plus de 20 nouveaux diterpènes ont été caractérisés, mais aucun d'entre eux ne présentait une activité antivirale significative. Pour résoudre ce problème, des réseaux moléculaires (MN) ont été construits grâce aux données de LC-MS/MS obtenues à partir des fractions chromatographiques des deux extraits. L'annotation des MN, a permis l'identification d'analogues du phorbol, connus pour être de puissants inhibiteurs du CHIKV. Présents à l'état de traces, ces composés fournissent une explication plausible à l'activité anti-CHIKV des deux extraits.Dans une deuxième étude, une stratégie de priorisation des extraits de plantes basée sur la fusion de données taxonomiques et d'essais biologiques au sein d'un MN a conduit à l'isolement et à la caractérisation ciblée de plusieurs inhibiteurs doubles de Codiaeum peltatum. Les deux études illustrent comment les MN et les progrès récents en matière d'annotation des données de LC-MS/MS peuvent être mis en œuvre dans les études phytochimiques pour améliorer le processus découverte de composés bioactifs. / In order to identify new inhibitors of chikungunya (CHIKV), dengue fever (DENV) and zika (ZIKV), systematic study with 339 extracts from tropical Euphorbiaceae species was performed in a virus-cell-based assay for CHIKV and DENV and ZIKA NS5 inhibition assaysThe French Guianese species Sandwithia guyanensis and Sagotia racemosa, from which bark extracts exhibited significant anti-CHIKV activities, were first investigated. Following a classical bioguided isolation workflow, more than 20 new diterpenes were characterized but none of them showed significant antiviral activity. To adress this issue, molecular networks (MN) were built from the LC-MS/MS data acquired from the chromatographic fractions of both extracts. The annotation of the MNs led to the identification of phorbol analogues, known to be potent CHIKV inhibitors. Present at trace levels, these compounds provide a plausible explanation for the anti-CHIKV activity of both extracts.In a second study, a strategy to prioritize plant extracts based on the fusion of taxonomic data and bioassays within a MN led to the isolation and targeted characterization of several dual inhibitors from Codiaeum peltatum. Both studies illustrate how MN and recent advances in LC-MS/MS data annotation can be implemented in phytochemical studies to improve the bioactive compounds discovery process.
24

Data-driven outbreak forecasting with a simple nonlinear growth model

Lega, Joceline, Brown, Heidi E. 12 1900 (has links)
Recent events have thrown the spotlight on infectious disease outbreak response. We developed a data-driven method, EpiGro, which can be applied to cumulative case reports to estimate the order of magnitude of the duration, peak and ultimate size of an ongoing outbreak. It is based on a surprisingly simple mathematical property of many epidemiological data sets, does not require knowledge or estimation of disease transmission parameters, is robust to noise and to small data sets, and runs quickly due to its mathematical simplicity. Using data from historic and ongoing epidemics, we present the model. We also provide modeling considerations that justify this approach and discuss its limitations. In the absence of other information or in conjunction with other models, EpiGro may be useful to public health responders. (C) 2016 The Authors. Published by Elsevier B.V.
25

Interaction of alphaviruses chikungunya and Semliki Forest with cells of the mononuclear phagocyte system

Zagrajek, Adrian Krzysztof January 2016 (has links)
Introduction Chikungunya virus (CHIKV) is an alphavirus in the family Togaviridae. Since 2005 the virus has caused a major epidemic of disease in humans, ranging from Central Africa, South-East Asia, Caribbean and more recently the Americas. The virus is spread by mosquitoes, most notably Aedes aegypti and Ae. albopictus. CHIKV causes an acute disease in humans, which is characterised by a rapid onset of high fever, rash, myalgia and arthralgia. The symptoms typically resolve within a week. Remarkably, up to a third of patients who recover from acute chikungunya develop chronic arthritis/arthralgia, which may last for months or years and has a large negative impact on the quality of life. The mechanism by which this occurs is not yet fully understood. CHIKV can infect human monocytes, and macrophages positive for CHIKV antigen have been observed in joint tissue from patients recovered from acute CHIKV infection but with chronic arthritis. Furthermore, it has been demonstrated that macrophages can be infected with CHIKV in vitro by a mechanism involving apoptotic debris from CHIKV-infected cells. Hypothesis and aims Infection of monocytes and macrophages with CHIKV contributes to clinical disease and virus persistence in vivo. The aim of this project was to investigate the mechanism by which alphaviruses infect macrophages in vitro, and to generate a CHIKV which is unable to replicate in monocytes and macrophages in vitro, and to study its pathogenicity in vivo. Materials and methods HeLa cells were infected with Semliki Forest virus (SFV), an alphavirus closely related to CHIKV, or SFV replicon particles (SFV VRP). Following cell death, whole cell supernatant or clarified cell supernatant from SFV- and SFV VRP-infected cells was passaged onto human monocyte-derived macrophages (MDMs). These cells were observed microscopically for expression of the fluorescent marker encoded by the SFV. Virus and VRP-infected apoptotic debris were inspected for the presence of alphavirus replication complexes by electron microscopy. Subsequently, a recognition element (RE) for a haematopoietic-specific miRNA (miR-142-3P) was incorporated into the genome of SFV (proof-of-concept) and CHIKV to investigate if blocking virus replication in cells of the mononuclear phagocyte system altered virus kinetics in vitro. The replication of the modified viruses was investigated in macrophage/monocyte cell lines Thp-1 and IC-21, and in HEK 293 cells modified to express miR-142-3P under the control of an inducible tetracycline promoter. Modified viruses were tested in animal models of disease (mouse for SFV and non-human primate for CHIKV) to investigate the pathogenicity of these viruses in vivo. Results The presence of apoptotic debris from SFV-infected cells was required to infect MDMs with SFV. The presence or absence of infectious virus particles in the apoptotic debris did not affect the infection rate. Intact alphavirus replication complexes were found within the apoptotic debris. MiR-142-3P RE was successfully incorporated into the genome of both SFV and CHIKV. RE-virus replication in all cells expressing miR-142-3P was reduced by 90-99% when compared to control viruses. RE-virus replication was not affected in cells which did not express miR- 142-3P. In interferon-α/β receptor knockout mice, RE-SFV generated viraemia comparable to the control virus, but could not infect efficiently the population of macrophages resident in the marginal zone of the spleen. RE-CHIKV was found to be genetically stable in vitro following multiple passages on BHK-21 cells in the absence of a selective pressure from miR-142-3P. RE-CHIKV was inoculated into two cynomolgus macaques. The data from this experiment are not yet available. Conclusion SFV was shown to infect MDM via apoptotic debris containing intact alphavirus replication complexes, which were the most likely infectious agent. SFV and CHIKV unable to replicate in haematopoietic cells in vitro were successfully engineered. The pathogenicity of modified SFV and CHIKV was investigated in vivo.
26

Zika virus is arriving at the American continent

Levy Blitchtein, Saul, Del Valle Mendoza, Juana Mercedes 08 1900 (has links)
Cartas al editor
27

Avaliação do perfil da resposta imune inata em pacientes infectados pelo vírus Chikungunya

Moizeis, Raíza Nara Cunha 06 April 2018 (has links)
Submitted by Automação e Estatística (sst@bczm.ufrn.br) on 2018-07-02T21:32:55Z No. of bitstreams: 1 RaizaNaraCunhaMoizeis_DISSERT.pdf: 1769599 bytes, checksum: 3f3015a21072896a64b31ea26d1e11be (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-07-09T11:36:32Z (GMT) No. of bitstreams: 1 RaizaNaraCunhaMoizeis_DISSERT.pdf: 1769599 bytes, checksum: 3f3015a21072896a64b31ea26d1e11be (MD5) / Made available in DSpace on 2018-07-09T11:36:32Z (GMT). No. of bitstreams: 1 RaizaNaraCunhaMoizeis_DISSERT.pdf: 1769599 bytes, checksum: 3f3015a21072896a64b31ea26d1e11be (MD5) Previous issue date: 2018-04-06 / A infecção pelo vírus Chikungunya causa alta morbidade devido principalmente a artralgia e artrite geradas. A inflamação induzida nas articulações pela infecção viral envolve a imunidade inata e adaptativa. Entretanto, os mecanismos imunológicos envolvidos na proteção ou patogênese não estão ainda, totalmente, elucidados. Dessa forma o objetivo do presente estudo foi avaliar as expressões de receptores da imunidade inata e citocinas induzidas por sua ativação em pacientes infectados pelo vírus Chikungunya. Neste estudo, foi avaliado a expressão de RNAm por PCR em tempo real dos receptores tipo Toll (TLR3, TLR7, TLR8, TLR9), RLR (MDA5 e RIG-1), Moléculas adaptadoras (TRIF e MyD88) e citocinas (IFNα, IFNβ, IFNγ, IL-6, IL-12 e TNFα) em sangue total de pacientes na fase aguda da infecção por Chikungunya (N=28) e em indivíduos saudáveis, não infectados (N=9) utilizados como grupo controle. Os pacientes infectados pelo CHIKV apresentaram aumento da expressão de RNAm de TLR3, em relação aos indivíduos saudáveis. Não foi observada diferença significativa da expressão de TLR7, TLR9, MDA5 e RIG-1 nos pacientes infectados pelo CHIKV, sendo observada, no entanto, uma redução da expressão de RNAm de TLR8, quando comparado aos indivíduos saudáveis. Nossos resultados indicam que a infecção pelo CHIKV em pacientes na fase aguda induz elevada produção de IFN-α, IFN-γ e IL-6, moléculas da imunidade inata, com ação antiviral provavelmente, devido ao reconhecimento do vírus por TLR3 e em menor proporção por MDA5 e RIG-1, além de mecanismos que, possivelmente, envolvam a colaboração de TLR9. Ainda, foram constatadas correlações positivas entre as expressões de RNAm de TLR3, TLR7, TLR9, MDA5 e RIG-1 com expressão IFN-α. De maneira interessante, também foram observadas correlações positivas entre as expressões de RNAm de TLR3 com IFN-α, IFN-γ e IL-12, e entre a expressão de RNAm de MDA5 com IFN-α, IFN-β, IFN-γ e IL-6, IL-12 e TNF-α. / Chikungunya virus infection cause high morbidity mainly due to arthalgia and arthritis generated. An inflammation induced in the joints by viral infection involve innate and adaptive immunity. However, the immunological mechanisms involved in protection or pathogenesis have not yet been completely elucidated. Thus the aim of the present study was to evaluate the expression of innate immunity receptors and cytokines induced by their activation in patients infected with the Chikungunya virus. In this study the expression of mRNA by real-time PCR of Toll receptors (TLR3, TLR7, TLR8, TLR9), RLR (MDA5 and RIG-1), adaptive molecules (TRIF and MyD88) and cytokines (IFN-α, IFN-β, IFN-γ, IL-6, IL-12 and TNF-α) in whole blood of patients in the acute phase of the Chikungunya infection (N=28). Uninfected cases (N=9) were used as negative controls. Pacients infected with CHIKV are older than TLR3 mRNA expression in relation to healthy languages. Influences of the expression of TLR7, TLR9, MDA5 and RIG-1 in CHIKV infected patients in the past have not been confirmed but have been shown to decrease TLR8 mRNA expression when they were found in the healthy populations. Factors related to CHIKV infection in pacients in the suck phase, infection with IFN-α, IFN-γ and IL-6, infections of innate immunity with antiviral action, recognition of the virus by TLR3 and to a lesser extent by MDA5 and RIG-1, in addition to mechanisms that possibly involve TLR9 collaboration. Furthermore, positive correlations were found between the mRNA expression of TLR3, TLR7, TLR9, MDA5 and RIG-1 with IFN-α expression. Interestingly, positive correlations between TLR3 mRNA expression with IFN-α, IFN-γ and IL-12 were also observed, and between MDA5 mRNA expression with IFN-α, IFN-γ and IL-12 were also observed, and between MDA5 mRNA expression with IFN-α, IFN-β, IFN-γ and IL-6, IL-12 and TNF-α.
28

Clonagem e expressão da proteína do capsídeo do vírus Chikungunya para produção de antígeno recombinante: Produção de antígeno recombinante através de gene sintético do vírus Chikungunya

Fernandes, Alana Batista, 92-98197-7160 19 April 2016 (has links)
Submitted by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2017-10-05T15:16:37Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação - Alana Batista Fernandes.pdf: 1845250 bytes, checksum: 5a81b4935b1849b58c0184317d0b69cf (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2017-10-05T15:17:10Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação - Alana Batista Fernandes.pdf: 1845250 bytes, checksum: 5a81b4935b1849b58c0184317d0b69cf (MD5) / Made available in DSpace on 2017-10-05T15:17:10Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação - Alana Batista Fernandes.pdf: 1845250 bytes, checksum: 5a81b4935b1849b58c0184317d0b69cf (MD5) Previous issue date: 2016-04-19 / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / The Chikungunya virus (CHIKV) is an RNA virus (family Togaviridae, genus Alphavirus) transmitted to humans through the bite of female mosquitoes Aedes aegypti and Aedes albopictus. The clinical onset in CHIKV infection is most often characterized by fever and joint pain, and so far there is no specific antiviral therapy or vaccine for the treatment of the infection. The diagnosis of CHIKV infection is based on clinical and laboratory findings, with the latter being performed by virus isolation, reverse transcription-polymerase chain reaction (RT-PCR), serology, and rapid tests: To produce a recombinant antigen through the cloning and expression of the capsid protein (C) of CHIKV in order to detect anti-CHIKV antibodies in human serum samples by immunoenzymatic assay. A synthetic gene (gBlock), specifically designed for this study, corresponding to the protein C (400 base pair) of Chikungunya virus, was amplified by polymerase chain reaction (PCR) and then cloned into pGEM-T Easy system-Escherichia coli. The transformant clones were sequenced, and recombinant products were digested using the restriction endonucleases EcoRI and BamHI, and then subcloned and expressed in the vector pET-23a+ Escherichia coli BL21 (DE3). The recombinant protein C expression and the molecular weight were determined by SDS-PAGE and Dot Blot and purified by affinity chromatography using nickel column. A immunoenzymatic assay was performed using the recombinant antigen to detect IgM and IgG antibodies in sera from patients with CHIKV infection confirmed by the National Reference Laboratory of the Ministry of Health, as well as sera from patients tested positive for Mayaro virus, Dengue virus and Cytomegalovirus infection. The derived recombinant protein showed size and antigenicity compatible with the native protein C from the CHIKV; a concentration of 0.342 ng/mL of recombinant protein C was obtained using the pET-23a+ E. coli BL21 (DE3); the affinity chromatography using nickel column was effective to obtain the soluble protein C, confirmed by the Bradford method; the immunoenzymatic assay using the recombinant antigen showed cross-reactivity to others Alphavirus pathogens. The results indicate that the expression system pET-23a+ E. coli BL21 (DE3) was effective to produce the recombinant protein C of CHIKV, however the antigen was not sensitive enough to detect only the CHIKV infection. / O vírus Chikungunya (CHIKV) é um vírus de RNA (família Togaviridae, gênero Alphavirus), transmitido aos seres humanos através da picada de mosquitos fêmeas de Aedes aegypti e Aedes albopictus. O início das manifestações clínicas da infecção por CHIKV na maioria das vezes é caracterizada por febre e dor nas articulações, e até agora não existe uma terapia antiviral específico ou vacina para o tratamento da infecção. O diagnóstico da infecção CHIKV é baseado em achados clínicos e laboratoriais, com o último sendo realizada por isolamento do vírus, transcrição reversa-polimerase reação em cadeia (RT-PCR), sorologia e testes rápidos. Para produzir um antígeno recombinante através da clonagem e expressão da proteína do capsídeo (C) de CHIKV de modo a detectar anticorpos anti-CHIKV em amostras de soro humano, por ensaio imunoenzimático. Um gene sintético (gBlock), especificamente concebidos para esse estudo, correspondente à proteína C do capsídeo (400 pares de bases) do vírus Chikungunya, foi amplificado por reação em cadeia da polimerase (PCR) e, em seguida, clonado em pGEM-T Easy sistema de Escherichia coli. Os clones transformantes foram sequenciados, e os produtos recombinantes foram digeridos com as endonucleases de restrição EcoRI e BamHI, e depois subclonado e expresso no vector pET-23a+ e Escherichia coli BL21 (DE3). A expressão da proteína C recombinante e o peso molecular foram determinados por SDS-PAGE e Dot Blot e purificado por cromatografia de afinidade utilizando uma coluna de níquel. Um ensaio imunoenzimático foi realizada utilizando o antígeno recombinante para detecção de anticorpos IgM e IgG em soros de pacientes com infecção CHIKV confirmados pelo laboratório nacional de referência do Ministério da Saúde, bem como soros de pacientes positivos para o vírus Mayaro, vírus da dengue e citomegalovírus infecção. O derivado da proteína recombinante mostrou tamanho e antigenicidade compatível com a proteína C nativa do CHIKV; uma concentração de 0,342 ng / mL de proteína C recombinante foi obtido utilizando o pET-23a+ de E. coli BL21 (DE3); a cromatografia de afinidade utilizando uma coluna de níquel foi eficaz para obter a proteína C solúvel, confirmada pelo método de Bradford; o ensaio imunoenzimático utilizando o antígeno recombinante mostrou reatividade cruzada com outros agentes patogénicos de Aphavírus. Os resultados indicam que o sistema de expressão pET-23a+ de E. coli BL21 (DE3) foi eficaz para produzir a proteína C recombinante de CHIKV, no entanto, o antígeno não foi suficientemente sensível para detectar apenas a infecção CHIKV.
29

Characterization of nsP-specific nanobodies targeting Chikungunya and Semliki Forest Virus

Andersson, Klara January 2020 (has links)
Viral infections are constantly increasing and impose a large threat to the public health. Alphaviruses are responsible for several animal and human diseases and have a large medical importance with few treatments available today. Alphaviruses are small, spherical single stranded RNA viruses, and are most often transmitted by mosquito vectors. Alphaviruses contains a domain of nonstructural proteins that compose the replication machinery. The domain is crucial for viral replication to occur and is therefore an interesting target for antiviral therapy. With the focus on Chikungunya and Semliki Forest Virus this work investigates the events in the cells on molecular level during infections. To do this a panel of Camelid derived single domain antibodies are developed to target the nonstructural proteins of Chikungunya and Semliki Forest Virus. Binding of the produced nanobodies to the viral proteins was investigated by biochemical methods including immunoprecipitations, western blot, and ELISA. Cell lines that express nsP-specific nanobodies in the cytosol were employed for infection- and plaque assays with Semliki Forest Virus in order to determine the antiviral potential of the new nanobodies. Three of the nanobodies proved to bind two different nonstructural proteins of the viruses, providing opportunities for further investigations and a possible use of these nanobodies to identify viral vulnerabilities that could be exploited for antiviral intervention.
30

Vectors and viruses in Southeast Africa and the Indian Ocean World: Aedes aegypti, chikungunya, and dengue in Durban, Natal

Rotz, Philip D. 08 June 2021 (has links)
This dissertation examines the nineteenth- and early twentieth-century history of the Aedes aegypti mosquito and the viral illnesses chikungunya and dengue from the Indian Ocean port town of Durban, South Africa. Histories of Ae. aegypti and yellow fever in the Atlantic World occupy an unmistakable niche in medical and environmental historiographies. Studies of this mosquito at home in Africa and abroad in the Indian Ocean World are lacking. This dissertation addresses that lacunae. A globally integrated industrial economy, mushrooming urban growth in tropical and subtropical regions, absent or overwhelmed municipal water supplies, faster forms of transportation, and rising levels of interconnection increase the likelihood of epidemics of viral illness transmitted by Ae. aegypti. Durban offers a vantage point to examine these transformations during the era of the New Imperialism. The Ae. aegypti mosquito casts Durban as the southwest corner of the Indian Ocean rimlands; East Africa’s southernmost urban center; and a humid subtropical settler society port and sugar region perched on the edge of ‘Neo-Europe.’ Facing the Indian Ocean World, I argue that explosive pandemics during the mid-1820s and early 1870s—traditionally attributed to dengue—were more likely chikungunya. Further, the absence of similar pandemics attributable to dengue suggests that virus was already endemic in the region’s leading ports, an indirect indication of Ae. aegypti’s presence in the region. This contests hypotheses suggesting this mosquito reached Asia via the Suez Canal. In Durban, epidemics of chikungunya and dengue during the 1870s reflect the port town’s connection to the Indian Ocean World and signal the presence of human-biting Ae. aegypti. I argue that clearing coastal forest for sugar production and town-building destroyed the ecological niche of indigenous sylvatic Ae. aegypti, while the agroecology of sugar and built environment of early Durban encouraged vector domestication and abundance in intimate proximity to people. Durban’s chikungunya and dengue past is largely forgotten. A study of the city’s history with Ae. aegypti is, therefore, timely. In an era marked by zoonoses and emerging and reemerging infectious diseases environmental histories must grapple with the entangled agencies of human and nonhuman actors—pests, pathogens, and people. / 2023-06-08T00:00:00Z

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