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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.
1

Zika Virus: Patient Education Recommendations

Towers, Victoria, Towers, Victoria January 2017 (has links)
As the current growing threat to maternal-fetal health, the most recent and largest outbreak of the Zika virus has introduced the devastating fetal effects of microcephaly and other central nervous system deficits. Therefore, the need for appropriate recognition, treatment, management, and prevention of the Zika virus prompts the necessity for further education and high quality level research to be conducted and utilized. A search of the literature using the databases PubMed, UptoDate, and CINAHL was conducted for articles published between 2009 and 2016. In addition, key informant interviews from various specialties including clinical genetics and public health were conducted. The proposed best practice recommendations for education regarding the Zika virus and appropriate prevention and treatment methods are outlined in an electronic education module that would be delivered to patients and their families prior to visiting their healthcare providers. As the Zika virus continues to spread and further research is conducted regarding its teratogenic effects, the need for concise and effective education is critical in order to raise awareness and conversely decrease the potential for maternal exposure and adverse fetal outcomes.
2

Detection of Zika virus infection among asymptomatic pregnant women in the North of Peru

Weilg, Claudia, Troyes, Lucinda, Villegas, Zoila, Silva-Caso, Wilmer, Mazulis, Fernando, Febres, Ammy, Troyes, Mario, Aguilar-Luis, Miguel Angel, del Valle-Mendoza, Juana 18 May 2018 (has links)
Objective: To report an outbreak of ZIKV infection among asymptomatic pregnant women during 2016 in the city of Jaen, Cajamarca. Results: Zika virus RNA was detected in 3.2% (n = 36) of cases by RT-PCR. The mean age of patients positive for ZIKV infection was 29.6 years. 7 patients (19.4%) infected with ZIKV were in their first-trimester of gestation, 13 (36.1%) were in their second-trimester, and 16 (44%) were in their third-trimester. All of the infected pregnant women were asymptomatic. ZIKV infection remains a major public health issue that calls for constant epidemiological surveillance. It can cause the congenital Zika virus syndrome in the newborns of infected mothers. The lack of molecular diagnostic methods in isolated localities and the similarity of symptoms to other arboviral infections, lead to an under-diagnosis of this disease in endemic areas. / Revisión por pares
3

Zika virus: control measures for an emerging pathogen in Brazil

Stetson, Alyssa 13 July 2017 (has links)
Zika virus (ZIKV), a member of the flavivirus family, was discovered in the Zika Forest of Uganda in 1947, subsequently diverged into two strains, and spread throughout Africa and Asia. Although it is believed to be endemic in these regions, its overall effects have been considered relatively benign, especially in comparison to other flaviviruses like dengue virus (DENV) and yellow fever virus (YFV). ZIKV is believed to have reached Brazil between June and August of 2014, although it may have arrived as early as between May and December 2013; by November 2014 doctors were reporting an increased incidence of cases with flu-like symptoms, and by March 2015 an increased incidence of microcephaly. These reports prompted an investigation into a possible association between ZIKV and microcephaly. Proof of causality can be illustrated through Shepard’s Criteria of Teratogenity “rare exposure-rare defect” approach, meeting the criteria of proven exposure to the agent, careful delineation of clinical cases, and rare environmental exposure with rare defect. Additionally, laboratory findings have discovered several possible mechanisms by which ZIKV can be vertically transmitted, as well as confirming that ZIKV is neurovirulent and disrupts the development of brain structures, especially when infection occurs during the first trimester. ZIKV is also possibly associated with other neurologic disorders: retrospective findings from a 2013 outbreak on French Polynesia linked ZIKV to the neurologic disorder Guillain-Barré syndrome (GBS). Microcephaly places a significant burden, both emotional and financial, on the affected families and the healthcare system. Therefore, there has been significant effort to develop a vaccine against ZIKV. While ZIKV is a suitable vaccine candidate in some aspects, it also has characteristics that make vaccine development challenging. First, the vaccine must be safe for pregnant women, since protecting them from disease transmission is the primary goal. Second, the vaccine must not cause adverse effects through cross-reacting antibodies, which may lead to antibody-dependent enhancement of infection in people who have been vaccinated against or infected with other flaviviruses, especially DENV. Currently, there are multiple vaccines in the earliest stages of development with three vaccines in Phase 1 trial. Researchers are also testing monoclonal antibodies and antimicrobial drugs for effectiveness against ZIKV. Given the high cost of these treatments they should be prioritized for pregnant women. ZIKV can be spread through vector transmission, sexual transmission, or blood transfusion. Although vaccine development is the ultimate goal, the most effective way of curtailing ZIKV transmission and reducing incidence of microcephaly is through vector control. Brazil already has vector control strategies in place to combat other mosquito-borne diseases, especially DENV, but its monitoring systems do not always accurately assess mosquito population density and location. There is also an overreliance on insecticide use, which is often ineffective and leads to mosquito resistance and potentially environmental damage. The most effective strategy for vector control is reduction of breeding sites through drainage of standing water, waste management and education about mosquitoes and personal protection measures. The other key strategy to reducing ZIKV transmission and the incidence of microcephaly is through education about condom use and access to safe abortions. While Brazil has worked to improve the former in the context of the HIV epidemic, with some success, abortions in Brazil are restricted. Data are scarce, but suggests that the number of women seeking abortions has increased due to ZIKV epidemic; limiting abortions leaves them vulnerable to unsafe procedures and at risk for complications that are avoidable. The ultimate goal for preventing ZIKV-associated congenital microcephaly, and other negative consequences of infection, is the development of a vaccine. However, implementing prevention methods against all mechanisms of ZIKV transmission is the best option to reduce the public health burden until such goal is achieved.
4

DIVERSIDADE Genética do Zika Virus no Estado do Espírito Santo

RODRIGUES, F. M. G. S. 06 March 2018 (has links)
Made available in DSpace on 2018-08-01T21:35:03Z (GMT). No. of bitstreams: 1 tese_12070_Dissertação_Fernanda Mariano Garcia.pdf: 3239009 bytes, checksum: d9dfe15fc9ef8127dc0144cec5fa3160 (MD5) Previous issue date: 2018-03-06 / O Zika virus (ZIKV) é um arbovírus do gênero Flavivirus pertencente à família Flaviviridae. Duas principais linhagens são reconhecidas, Asiática e Africana, sendo a linhagem Asiática encontrada no Brasil. Os sintomas da infecção de ZIKV geralmente são brandos, mas existem relatos de casos de óbitos e manifestações neurológicas. Variações genéticas virais estão relacionadas com as diferenças nas manifestações clínicas da doença, portanto pesquisas sobre o genoma, filogenia e distribuição geográfica do vírus podem esclarecer como essas variações afetam a manifestação clínica do ZIKV, além de servir para o desenvolvimento de produtos biotecnológicos. Apesar da importância, poucos estudos avaliam as variações genéticas virais. Este estudo realizou uma abordagem epidemiológica e filogenética a nível populacional que analisou a diversidade genética do ZIKV no Espírito Santo (ES), e as relações filogenéticas das cepas de ZIKV identificadas com sequências virais disponíveis no GenBank. Constatou-se que os municípios de Vitória, Cariacica e Cachoeiro de Itapemirim foram os mais afetados, sendo a linhagem Asiática a circulante no ES, assim como no restante do país. Foram encontradas 4 variações em 2 genes estudados, no gene E A1023G e C1050T e no gene NS5 C1891T e T1945C. As variações A1023T e C1891T foram descritas pela primeira vez em linhagens Asiáticas neste trabalho, e as variações C1050T e T1945C foram descritas anteriormente em linhagem Asiática apenas uma vez em uma sequência do Rio de Janeiro e três sequências na China, respectivamente. Por fim, apesar das variações genéticas encontradas nas sequências do ES não estarem associadas à mudança de aminoácidos, não se pode descartar que outras mudanças, seja em ligações entre enzimas e o RNA, seja na estrutura das proteínas finais, podem ser causadas por essas variações. Os resultados apresentados podem ser úteis a futuros trabalhos permitindo uma expansão da base de dados apresentando uma visão mais clara da epidemiologia do ZIKV, o que poderá ajudar a determinar a origem geográfica de um novo surto e, além disso, monitorar a eficácia das medidas de controle.
5

Immune signatures of viral control in nonhuman primates

January 2020 (has links)
archives@tulane.edu / Immune signatures are patterns of gene and protein expression in immune cells that characterize states of activation and response. As such, signatures indicative of viral control during natural infection may guide vaccine development efforts to achieve similar patterns of protection. Here, we used nonhuman primate (NHP) models of Zika virus (ZIKV) and simian immunodeficiency virus (SIV, as a model for HIV) to explore outcomes of infection in these important human pathogens. We employed a multifaceted approach including high dimensional flow cytometry and RNA sequencing to understand cellular responses to ZIKV generally and during pregnancy, as well as to identify the impacts of infection in astrocytes, a neuroglial target of ZIKV thought to be important in the development of neurologic disease. We found that CD8 T cells may restrict ZIKV persistence in tissues but ultimately have a minimal role in protection to either primary or secondary challenge. However, we showed that immune manipulation, either naturally through pregnancy or artificially through depletion experiments, can skew metabolic and innate immune pathways in unexpected ways. While cellular immunity appeared to minimally impact ZIKV infection, such responses in SIV are important in controlling viral replication, which we inversely showed by tracking patterns of viral mutation to evade CD8 responses. We also identified transcriptional signatures in ZIKV infection that may underlie the development of neurologic diseases and found that different virus lineages have unique impacts on gene expression. Together, these experiments showcase the utility of profiling approaches in understanding the immune complexity that accompanies viral infection. / 1 / Blake Schouest
6

Undestanding the viral molecular factors involved in Zika virus pathogenicity in humans / Compréhension des facteurs viraux moléculaires impliqués dans la pathogénicité du virus Zika chez l'homme

Bos, Sandra 18 April 2019 (has links)
Le virus Zika (ZIKV) est un phénomène épidémiologique sans précédent qui surprit le monde entier. Pendant de nombreuses années, il fut considéré comme un virus anodin responsable d’une poignée d’infections humaines, auto-limitées et bénignes, en Afrique et en Asie du Sud-est. Mais, après des décennies de propagation silencieuse, une première épidémie éclata en Micronésie en 2007 - tel un signal d'alarme. Quelques années plus tard, une soudaine épidémie de ZIKV de plus grande ampleur se déclara dans les îles du Pacifique avant d'atteindre le Brésil en 2015. Au cours de cette période, Zika fut associé à de graves complications neurologiques, mettant en évidence son fort potentiel pathogène pour l'homme. Depuis son émergence, plus de 80 pays et territoires ont été touchés par la pandémie de ZIKV, désormais reconnu comme un virus neurotrope et tératogène. L'association des souches contemporaines de ZIKV à des formes graves de maladie chez l'homme, qui n'ont jamais été signalées auparavant, a soulevé l'hypothèse d'une pathogénicité nouvellement acquise. Ainsi, mes travaux de doctorat visaient à déterminer si l'ampleur de l'épidémie actuelle pouvait en partie avoir été facilitée par des facteurs viraux qui auraient renforcé la fitness du ZIKV. À cette fin, mon projet de recherche s'est concentré sur l'identification des facteurs moléculaires viraux impliqués dans la pathogénicité du virus Zika chez l’homme à partir du développement de clones moléculaires. / Zika virus (ZIKV) is an unprecedented epidemiological phenomenon which surprised the world. For many years, it was considered a trivial virus responsible for only a handful of human infections, self-limited and benign, in Africa and Southeast Asia. But then, after decades of silent spread, a first epidemic broke out in Micronesia in 2007 – like a warning signal. A few years later, a sudden Zika outbreak of larger scale occurred in the Pacific islands before reaching Brazil in 2015. During this period, Zika was associated with severe neurological complications, highlighting its serious pathogenic potential for humans. Since its emergence, more than 80 countries and territories have been affected by the ZIKV pandemic, which is now recognized as a neurotropic and teratogenic virus. The association of contemporary ZIKV strains with severe forms of disease in humans, that have never been reported before, has raised the hypothesis of newly acquired pathogenicity. In this regard, my doctoral research aimed to determine whether the scope of the current epidemic was partly facilitated by viral factors that improved ZIKV fitness. To this end, my research project focused on the identification of the viral molecular factors involved in Zika virus pathogenicity in humans based on the development of molecular clones.
7

Genetic and Infectious Causes of Microcephaly: NDE1 Mutations Compared to the Zika Virus

Doobin, David J. January 2017 (has links)
Brain development is an exquisitely coordinated process of progenitor cell proliferation followed by the migration of progeny to their final location in the developing brain. There are a myriad of points at which this process can be disturbed, and the examination of these perturbations help us further understand basic science, as well as epidemics sweeping through the world around us. Microcephaly, which is defined as a head circumference greater than 2 standard deviations below the mean, can occur through genetic, infectious, vascular, or metabolic etiologies, and the studies herein examine two forms by which microcephaly occurs. First, we investigate the role of the dynein regulatory protein Nde1 in the development of the neocortex, which is the outer region of the forebrain. NDE1 mutations are associated with severe microcephaly, and we find that unlike most microcephaly genes whose products have one role in the cell cycle, Nde1 is required at three discrete points in neuronal progenitors, termed radial glia progenitors (RGPs). We initially find that Nde1 is required to recruit dynein to the nuclear envelope to allow for interkinetic nuclear migration (INM) during G2. Additionally, Nde1 helps to initiate primary cilia resorption at the G1-to-S transition. Finally, there is a necessity for Nde1 at the G2-to-M transition after the completion of INM and prior to nuclear envelope breakdown. These three distinct roles for Nde1 illustrate the breadth of functions that the protein has during RGP proliferation, and help to explain why patients with NDE1 mutations have such severe microcephaly. As this work was ongoing there was a global outbreak of a new pathogen that had previously been dormant throughout Africa and Asia, only to emerge at epidemic proportions in the Western Hemisphere. This pathogen, the Zika Virus (ZIKV), is particularly alarming because of its subclinical course in adults but devastating consequences for fetal development, with the hallmark symptom being microcephaly. Using our organotypic brain slice model system, we demonstrate the ability of a variety of ZIKV isolates to infect and replicate in embryonic brain tissue. All ZIKV isolates that infect the organotypic slices lead to increases in apoptosis, though these increases are particularly pronounced in isolates from the Asian/American lineages. Notably, one isolate from a patient in Nigeria (termed 30656) does not replicate in mouse neuronal tissue, but electroporation of the 30656 ZIKV genome allows for a single cycle replication, suggesting that this isolate is unable to enter RGPs. All infectious isolates are pathogenic in early- and mid- gestation embryonic tissue, but only one isolate infects and replicates in late- gestation embryonic tissue. This was the most recently isolated sample tested, and it demonstrates a predilection for neurons, suggesting that ZIKV may be mutating as it spreads. These results provide foundational insight into the pathogenesis of ZIKV- associated microcephaly, and illustrate how studies of genetic forms of microcephaly can enhance and facilitate our understanding of infectious causes of the disease.
8

Antibody dependent enhancement: a model for understanding congenital Zika syndrome

Eichen, Eva 24 October 2018 (has links)
This literature review will discuss Zika virus and the salient research on antibody dependent enhancement and how this mechanism may lead to congenital defects. Specific objectives include: the mechanism of antibody dependent enhancement, Zika and dengue virus pathogenesis, placenta pathophysiology, and how changes in viral virulence may play a role the pathogenesis of neurologic congenital defects seen in infants infected with Zika virus in utero. While some cohort studies have examined the relationship between prior dengue immunity, Zika virus infection in pregnancy, and effects on neonatal outcomes further prospective studies using large cohorts and more detailed lab testing and imaging is essential to better understand this relationship. A proposed study enrolling a large cohort of women in the 6th- 8th week of pregnancy from Northeastern Brazil will seek to further describe what additional risk dengue immunity may pose in the context of Zika virus. This risk is essential to understand, as Zika and Dengue viruses co-circulate in many regions of the world. Furthermore, participants in the proposed study will undergo bi-weekly screening for Zika virus through laboratory and ultrasound testing until their delivery. Infants will then have full neurologic testing and MRI scanning for the following year after birth to characterize any congenital defects. Neonates born to mothers with prior dengue immunity who contract Zika virus during pregnancy will be compared to neonates not exposed to Zika virus in utero. This experiment will illuminate the associated risk and evidence of ADE occurring with prior dengue immunity and Zika virus infection during pregnancy. Results from this study will not only help define risks of congenital defects with Zika virus, it will inform vaccine research and elucidate challenges in the administration of the current tetravalent dengue vaccine.
9

Zika virus is arriving at the American continent

Levy Blitchtein, Saul, Del Valle Mendoza, Juana Mercedes 08 1900 (has links)
Cartas al editor
10

Mechanistic investigation of flavivirus repression by diverse Wolbachia strains in mosquito cell lines

Schultz, Michaela Jane 18 July 2018 (has links)
Arboviruses are blood-borne pathogens that threaten half of the world’s population. The recent outbreak of Zika virus (ZIKV) in Brazil has highlighted the importance of developing new strategies to limit virus spread. While vaccines are in development, one way to immediately suppress viral transmission is through biocontrol of mosquito vector. Novel biocontrol strategies utilize microbe – mosquito interactions to inhibit the transmission of pathogens. A powerful tool under investigation is the intracellular bacteria, Wolbachia pipientis, which are maintained in insect populations through maternal transmission. The Wolbachia strain wMel can be trans-infected into mosquitos limiting ZIKV transmission. However, thermal stress can hinder maternal transmission of the wMel strain of Wolbachia. For Wolbachia-based technologies of vector control, it is important to have additional strains with viral suppression capabilities available. We characterized alternative Wolbachia strains in A. albopictus mosquito cell lines and the underlying mechanisms of these interactions. We identified two novel Wolbachia strains with robust arbovirus repression. wAlbB, native to mosquitos blocked 90% of ZIKV growth. More strikingly, wStri, a nonnative symbiont, ablated ZIKV growth in A. albopictus cells below the limit of detection. After showing that ZIKV growth is rescued in wStri infected A. albopictus cells by the pharmacological removal of Wolbachia, we established these cells as an in vitro model for mechanistic studies. Using novel labeling and reporter techniques, we isolate a block in virus growth by Wolbachia at two stages of viral growth, entry and translation. We further show that cholesterol, which can partially rescue viral growth in Wolbachia wStri infected cells, aids in viral entry but does not promote viral growth post entry. Beyond our Wolbachia studies, we further investigated the limited arbovirus growth observed in many A. aegypti cell lines and identified two insect–specific viruses which interfere with arbovirus growth. To address the limited biocontrol tools in C. pipiens mosquitos, we characterized commensal microbiota that may be used as a direct competitor of viruses or as a tool to genetically enhance an antiviral response in the mosquito gut. Together this work expands our understanding of Wolbachia-mediated biocontrol strategies and offers novel resources to suppress arbovirus transmission. / 2020-07-18T00:00:00Z

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