Made available in DSpace on 2015-10-06T13:02:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-07-14. Added 1 bitstream(s) on 2015-10-06T13:19:29Z : No. of bitstreams: 1 000849126.pdf: 1214857 bytes, checksum: a2d47dd516d137071a1aa19d9f8af738 (MD5) / A nucleoproteína (NP) do Vírus da Influenza Aviária (VIA) é um importante alvo antigênico no imunodiagnóstico desta doença, devido à sua baixa variabilidade entre as diferentes estirpes do VIA, resultando em uma elevada reatividade cruzada, e por ser também uma proteína altamente imunogênica para hospedeiros vertebrados. Neste estudo, o gene codificador da NP do VIA foi parcialmente clonado e expresso em Escherichia coli como uma proteína recombinante fusionada ao polipeptídeo SUMO e uma etiqueta de poli-histidina para seu uso no desenvolvimento de um ensaio de ELISA indireto para a detecção de anticorpos específicos contra o VIA. A NP recombinante foi expressada na fração solúvel e foi mais facilmente purificada. Após análise em relação aos seus principais sítios de antigenicidade e caracterização por meio de Western blotting, a NP recombinante foi utilizada como uma preparação antigênica no ELISA indireto para detecção de anticorpos contra o VIA presentes em amostras de soro de galinha. A análise comparativa do teste desenvolvido no presente estudo com um ELISA comercial apresentou valores de 95%, 97% e 96,7% de sensibilidade, especificidade e acurácia, respectivamente e um índice κappa de 0,88. Os resultados permitem concluir que a NP recombinante do VIA desenvolvida neste estudo possui características favoráveis para ser aplicada como antígeno no ELISA indireto, constituindo-se em um método sensível e específico para o imunodiagnóstico da Influenza Aviária em galinhas / The nucleoprotein (NP) of Avian Influenza Virus (AIV) is an important antigenic target for immunodiagnosis of this disease, due to its low variability among different AIV strains, resulting in high cross-reactivity, and the also highly immunogenic for vertebrate hosts. In this study, the gene enconding NP of AIV was cloned and expressed in Escherichia coli as a recombinant protein fused to SUMO polypeptide with a polyhistidine tag and used to develop an indirect ELISA for the detection of AIV-specific antibodies. The recombinant NP was expressed in the soluble fraction and easily purified. After Analysis of the main sites of antigenicity and characterization in Western-Blotting, the recombinant NP was optimized as an antigen preparation for indirect ELISA to detect anti-AIV antibodies in chicken serum samples. The comparative analysis of this ELISA with a commercial ELISA showed values of 95%, 97%, 96.7% of sensitivity, specificity and accuracy, respectively, and an agreement of k=0.88. In conclusion, the results indicated that the recombinant NP of AIV produced in this study is a good source of antigen for indirect ELISA and provides a sensitive and specific method for the immunodiagnosis of Avian Influenza in chickens

Master of Science / Department of Diagnostic Medicine/Pathobiology / Alison Paige Adams / Avian influenza (AI) is a zoonotic disease that has garnered much attention in recent years due to its detrimental effects on poultry, producers and potentially human health. This disease can be extremely fatal to domestic poultry, killing as high as 90-100% of the flock. This virus has the potential to cause devastation to and loss of entire flocks. AI is typically spread between wild fowl and domestic poultry with a zoonotic potential to also affect human health as well as other animals. Its spread also has a massive economic impact due to the decreased amounts of available poultry products to consumers around the world. This report will examine the worldwide history and epidemiology of highly pathogenic avian influenza (HPAI). In the last ninety-two years, there have been five recorded outbreaks of HPAI in the United States (US). Globally, notable outbreaks have occurred in Italy (1997-2001), the Dutch region of Europe (2003), Canada (2004), and more recently, in Asia. Preventative measures will be examined in this report. In particular, biosecurity, quarantine, surveillance, and eradication are some of the most widely recognized and accepted ways to help prevent and control HPAI outbreaks. However, none of these methods are failsafe strategies to completely prevent or control the spread of HPAI. This report will focus on an additional preventative measure - currently available and potential future vaccination programs. There is a global shift toward procuring poultry that are AI-free as well as unvaccinated for AI. This is, in part, due to the limitations of currently available vaccines in completely ridding poultry of this disease. Vaccinations may reduce the amount of virus in infected birds, but this does not prevent birds from becoming infected. When addressing the control and eradication of HPAI, some future challenges include viral mutations, intermingling of domesticated and wild birds, and vaccine development. Because of the current limitations of vaccines and future challenges in controlling the spread of infection, there is no one single solution to this problem. It will require a multi-faceted approach.

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Please read the abstract in the secton 00front of this document. / Thesis (PhD (Zoology))--University of Pretoria, 2007. / Zoology and Entomology / unrestricted

These recent events of H1N1 flu outbreak illustrate the potential ramifications of infectious diseases on modern society and how society responds to these threats. This thesis addresses the specific case of avian influenza in U.S. poultry production. By building an expected utility maximization model for integrators contracting with growers of varying bio-secure levels, one can investigate the relationship between the bio-secure choice of the poultry industry and their production performance. The model is empiricized using the Phoon, Quek, and Huang (PQH) simulation technique to conduct numerical analysis. The model selects the optimal percentage of bio-secure farms for the integrators to contract, output price reductions due to disease outbreak, and different probabilities of disease outbreak. Results allow the examination of whether alternative USDA/APHIS indemnification rules can sufficiently influence integrators willingness to improve their bio-security level.

A 4.0 Kb (2.64 Mdal) plasmid was isolated from a fowl cholera strain of Pasteurella multocida (the Larsen strain) by alkaline lysis and cesium chloride purification. The plasmid, designated pLAR-1, was characterized in terms of its size and restriction sites. The restriction patterns produced by fourteen endonucleases were used to generate a restriction map. Five restriction enzymes cleaved the plasmid at multiple sites. Two enzymes, Bgl II and Sal I had unique sites on pLAR-1. Twelve of the fifty six strains of P. multocida surveyed contained plasmids of different sizes which hybridized to pLAR-1. Strains containing homologous plasmids were variable in serotype, dermonecrotoxin production, and origin (both in terms of the host and locale). pLAR-1 did not encode any of the enzymes necessary for the biochemical pathways contained within the API-20E strip or siderophore production. pLAR-1 was cloned into the BamH I site of pBR322. Resultant clones were approximately 8.363 Kb in length, ampicillin resistant and tetracycline sensitive. The pLAR-1 / Master of Science

published_or_final_version / abstract / toc / Microbiology / Doctoral / Doctor of Philosophy

Thesis (M.P.A.)--University of Hong Kong, 1999. / Includes bibliographical references (leaves 68-69).

Thesis (M.P.A.)--University of Hong Kong, 1999. / Includes bibliographical references (leaves 68-69). Also available in print.

published_or_final_version / Public Administration / Master / Master of Public Administration