West Nile virus affected nearly 2,000 people in Texas in 2012, killing 89. Neither state and local public health institutions nor the medical community were well prepared for the unprecedented outbreak. The virus is carried by mosquitoes and can cause paralysis and other neurological damage. Other diseases carried by insect vectors, like dengue fever, are poised to resurge or emerge in Texas. Suspected effects of climate change, like warmer winters, may contribute to the prevalence of such diseases and frequency of outbreaks. Adequate surveillance of human cases of these diseases is crucial to the public health response, but is hampered by a low level of diagnosis and reporting throughout the state and spotty vector surveillance by local entities. / text

Mosquito species of the Culex genus are the enzootic vectors for several bird-associated viruses that cause disease in humans. In Europe, these viruses include Sindbis (SINV), West Nile and Usutu viruses. The morphologically similar females of Cx. torrentium and Cx. pipiens are potential vectors of these viruses, but difficulties in correctly identifying the mosquito species have caused confusion regarding their respective distribution, abundance, ecology, and consequently their importance as vectors. Species-specific knowledge from correctly identified field material is however of crucial importance since previous research shows that the relatively unknown Cx. torrentium is a far more efficient SINV vector than the widely recognized Cx. pipiens. The latter is involved in the transmission of several other viruses, but its potential importance for SINV transmission is debated. In this thesis I describe the development of a molecular method for species identification, based on reliably identified males of Cx. torrentium and Cx. pipiens. This identification method was then used in consecutive studies on the distribution and relative abundance of the two species in Sweden and 12 other European countries, SINV field infection rates in mosquitoes identified to species level, and evaluation of potential trap bias associated with common sampling techniques. The results showed that Cx. torrentium is a far more common species in Europe than previously assumed. In Sweden and Finland, it is the dominant species, accounting for 89% of the sampled Culex population. In central Europe, it is equally common to Cx. pipiens, while Cx. pipiens dominates south of the Alps Mountain range. Larvae of both species are often found together in both artificial containers (e.g. car tires) and natural sites. Also, a trapping bias against Cx. torrentium was revealed for CDC-traps. For the first time, SINV was isolated from species-identified Cx. torrentium and Cx. pipiens mosquitoes caught in the field, with Cx. torrentium being superior in infection rates (36/1,000 vs. 8.2/1,000). Future studies on SINV, as well as other mosquito-borne bird viruses in Europe, can hopefully gain from the baseline information provided here, and from principles of vector discrimination discussed in the thesis.

Produced through relations of power, West Nile Virus (WNV) as it exists on the Public Health Agency of Canada's (PHAC) website, is an effect of the kinds of knowledge, techniques of power. and disciplinary apparatuses that operate on the website and in society. Cumulatively, these forces have produced WNV as a bio-socio-administrative construct. With reference to Michel Foucault's relations of power and to Jennifer Gore's operationalization of Foucault's techniques of power, this thesis both describes the PHAC's overall production of WNV and analyzes the production process. This thesis illustrates one way that Foucault's theories of power can be used to conduct a social construction analysis. The study also shows conclusively that power relations are an important factor in the production of newly emergent infectious diseases in Canada. It will be of value to other researchers who are interested in the sociological study of disease, public health, and risk.

Das West-Nil-Virus (WNV) ist eine Zoonose mit weltweit zunehmender Verbreitung. Natürliches Reservoir dieses Flavivirus sind Vögel, aber auch Säugetiere wie z.B. Menschen können infiziert werden. In einigen Fällen führt eine WNV-Infektion zu schweren neurologischen Erkrankungen. Infolgedessen werden effektive und biologisch sichere Impfstrategien gegen dieses Virus benötigt. Eine Alternative zu herkömmlichen Impfmethoden beschreibt die DNA-Immunisierung. In dieser Arbeit wurde ein potentieller DNA-Impfstoff gegen das WNV hergestellt. Die Immunisierung des DNA-Vektors induzierte starke zelluläre und humorale Immunantworten in Mäusen. Zudem waren die Tiere gegen eine WNV-Infektion geschützt. Zusätzliche Impfungen mit rekombinantem WNV-Protein führten zu einer weiteren Steigerung der Immunogenität des DNA-Impfstoffkandidaten. Des Weiteren sollte der nicht-virale Gentransfer im Allgemeinen optimiert werden. Ein neu entwickeltes Transportsystem für Plasmid-DNA, bestehend aus natürlichen Histonextrakten und Polyethylenimin, resultierte in einer verbesserten Proteinexpression in in vitro transfizierten Zellen und wurde von diesen sehr gut toleriert. Daher wäre diese Strategie auch für zukünftige DNA-Impftechniken denkbar. Der Einfluss von WNV auf die Expression zellulärer miRNAs in Wirtszellen wurde bisher noch nicht untersucht. Dennoch könnten auf diese Weise potentielle molekulare Biomarker für eine frühe WNV-Diagnose identifiziert werden. Mittels Microarray-Technik wurde die Expression zellulärer miRNAs analysiert. Verschiedene miRNA-Spezies waren infolge einer WNV-Infektion leicht herunter- bzw. hochreguliert und stellen mögliche diagnostische Biomarker für das Virus dar.

Since the establishment of West Nile virus (WNV) in North America, concern has arisen that this virus may also pose a biosecurity threat to Australia. West Nile virus is maintained in an enzootic transmission cycle between birds and ornithophilic Culex spp. mosquitoes. Since its introduction into the United States in 1999, it has been responsible for over 11,000 human cases of neurological disease and over 1,000 human deaths. In addition, WNV has caused extensive equine and avian mortality. Should an exotic, virulent strain of WNV be introduced into Australia, it may have significant impact on human and animal health. This thesis examines entomological factors which may influence the potential for an exotic, pathogenic strain of WNV to become established in eastern Australia and be maintained in urban transmission cycles. Further, it aims to elucidate the most likely candidate vectors for the maintenance of WNV in natural transmission cycles. Components include: a) laboratory-based vector competence experiments to assess the ability of Australian mosquito species to become infected with and transmit a North American strain of WNV; b) identification of the vertebrate origin of mosquito bloodmeals using serological and molecular assays; c) an evaluation of the efficacy of bird-baited traps for collecting ornithophilic mosquitoes at ground level and in the tree canopy; and d) examination of the prevalence of endemic arboviruses, including Kunjin virus (KUNV; an Australian subtype of WNV) in mosquitoes collected from urban centres of eastern Australia. Vector competence experiments were conducted with field-collected Australian mosquito species. Nineteen species were were exposed to a 1999 New York strain of WNV using an artificial membrane feeding apparatus and transmission was attempted using an in vitro modified capillary tube method. A number of Culex species, including Culex quinquefasciatus and Culex gelidus, demonstrated high vector competence for WNV. Culex annulirostris, the primary KUNV vector, was the most competent vector, displaying transmission rates of 84%. Other common species, including Aedes vigilax, Aedes procax and Verrallina spp. were less susceptible to infection. Approximately 1,200 blood engorged mosquitoes were analysed using an enzyme-linked immunosorbent assay to determine host species. Overall, 90% of bloodmeals from Cx. quinquefasciatus were avian in origin, while 22% of bloodmeals from Cx. annulirostris were from birds. Molecular assays were further used to determine which bird species were commonly targeted by a selection of ornithophilic mosquito species. Mitochondrial DNA sequence data indicated that most (93%) avian bloodmeals from Cx. quinquefasciatus were obtained from passerine birds (order Passeriformes). Avian species commonly targeted by Cx. quinquefasciatus included Sphecotheres vieilloti (Australasian figbird; 39% of total identified), Sturnus tristis (common myna; 19%) and Philemon buceroides (helmeted friarbird; 17%). Alternatively, the majority (87%) of avian bloodmeals identified from Cx. annulirostris were from non-passerine birds, with most bloodmeals obtained from ducks (72%; family Anatidae). Seven field-based Latin Square trials conducted in Brisbane and Cairns showed that conventional CO2-baited CDC traps yielded higher numbers of Culex spp. than novel bird-baited traps, both at ground level and in the tree canopy. In Brisbane, CO2-baited CDC traps placed at ground level (approximately 1 m from ground) collected significantly more Cx. annulirostris than those at canopy height (5-10 m) during two trials, and more Ae. vigilax and Aedes procax during one trial each. Conversely, in Cairns, CO2-baited CDC traps placed in the tree canopy collected significantly more Culex squamosus during two trials, and significantly more Aedeomyia catasticta and Culex cubiculi during one trial each. Consistently low yields of ornithophilic species including Culex australicus and Cx. quinquefasciatus in all traps tested suggests the need to employ alternative trapping measures to target these species in urban areas. Over 1,800 mosquito pools (comprising over 65,000 individual mosquitoes collected from urban environments) were tested for evidence of arboviral infection. None of the pools showed evidence of flavivirus infection, but two alphaviruses were isolated from mosquito pools from Cairns. One isolate of Barmah Forest virus was obtained from a pool of 100 Ae. vigilax, and a pool of 89 Verrallina carmenti yielded an isolate of Ross River virus. In addition, an isolate most similar to a newly described bunyavirus, Stretch Lagoon orbivirus, was obtained from a single Aedes alternans collected from Sydney. The outcomes of this thesis demonstrate that a number of Australian mosquito species can become infected with and transmit a virulent strain of WNV, should it be introduced into Australia. Analysis of the host feeding patterns of these potential vectors in urban environments demonstrates that a number of candidate vectors, including Cx. quinquefasciatus and Cx. annulirostris, readily feed on common bird species. Further, the absence of detectable flavivirus infection in urban mosquito populations shown here suggests that endemic urban flaviviruses would have minimal influence on potential WNV transmission. Notwithstanding other ecological factors that may influence the likelihood of enzootic or epizootic transmission including susceptibility of vertebrate hosts and mechanisms of introduction, the potential establishment of an exotic, virulent strain of WNV in urban areas of Australia is certainly possible given the evidence provided in this thesis.

Thesis (M.S.)--University of Nevada, Reno, 2006. / "December, 2006." Includes bibliographical references (leaves 29-33). Online version available on the World Wide Web. Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2006]. 1 microfilm reel ; 35 mm.

Thesis (Ph.D.)--University of Alabama at Birmingham, 2010. / Title from PDF title page (viewed on July 7, 2010). Includes bibliographical references.

Thesis (M.S.) -- University of Tennessee, Knoxville, 2005. / Title from title page screen (viewed on July 13, 2005). Thesis advisor: Reid R. Gerhardt. Document formatted into pages (xii, 77 p. : ill. (some col.), maps (some col.)). Vita. Includes bibliographical references (p. 67-76).

Thesis (M.S.) -- Mississippi State University, 2006. / Includes bibliographical references (p. 91-96). Available online in PDF format.

Thesis (M.S.)--Montana State University--Bozeman, 2007. / Typescript. Chairperson, Graduate Committee: Gregory D. Johnson. Includes bibliographical references (leaves 60-66).