2 parts in 1 vol. : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (D.D.S.)--University of Adelaide

Fish diseases and various parameters associated with disease caused mortality of fish were monitored at the Oregon State University Marine Science Center and at a private mariculture facility on Yaquina Bay during a period of five years. Nearly all disease problems observed were caused by Vibrio anguillarum and Vibrio spp. Infection by Vibrio spp. resulted in substantial mortality (as high as 50% of a population) among fish which were immunized against two serotypes of V. anguillarum and among non-immunized fish. Naturally occurring levels of V. anguillarum in Yaquina Bay were determined to be ten or less viable cells per ml water. Effluent water from groups of salmonids with naturally acquired vibriosis contained 1.0 to 4.3 x 10�� viable cells of V. anguillarum per ml. The histopathology associated with naturally acquired and experimentally induced infections of vibriosis in chum salmon fingerlings was described for the two serotypes of V. anguillarum which commonly cause epizootic levels of mortality among salmonids reared at mariculture facilities in the Pacific Northwest United States. Results of these studies indicate that different histopathologic changes are produced by the two serotypes of V. anguillarum. One serotype (referred to as V. anguillarum serotype I) produced a bacteremia in early stages of disease with the following organs and tissues being the main targets: blood, loose connective tissue, kidney, spleen, posterior gastrointestinal tract, and gills. The second serotype (referred to as V. anguillarum serotype II) produced a bacteremia in late stages of disease with the following organs and tissues being main targets: skeletal muscle, cardiac muscle, anterior gastrointestinal tract, posterior gastrointestinal tract, and gills. Vibrio anguillarum serotype I cells were evenly dispersed throughout infected fish tissues while V. anguillarum serotype II formed distinct colonies in tissues of fish. Experimentally induced infections of chum, coho, and chinook salmon were studied to compare the histopathologic changes associated with infections of V. anguillarum serotypes I and II and to obtain. quantitative data concerning some specific effects produced in fish infected with these organisms. Differences in histopathology noted above were observed in all three species of fish when infections of the two serotypes of V. anguillarum were compared. Cellular responses were rarely observed during early or late stages of vibriosis. The data suggest that both serotypes of V. anguillarum used in these studies produce a leukocidin in fish because infected fish had 80% to 95% less leukocytes than non-infected control fish. Extremely high levels of V. anguillarum were shown to be present in fish tissues. Pathology observed in the mucosa of the gastrointenstinal tract of infected fish was apparently related to pH. The anterior gastrointestinal tract was strongly acidic and contained no necrosis of the mucosa while the posterior gastrointestinal tract was not acidic and contained massive necrosis and sloughing of epithelial cells in the mucosa. Experimentally induced infections of vibriosis with water born exposure of fish to live bacteria were used to study the progress of disease. Both serotypes of V. anguillarum used in these studies were shown to enter fish by penetrating the descending intestine and rectum. Penetration of the skin is a second means by which V. anguillarum serotype II enters fish. Moribund fish in all studies suffered from hypoxia, possible accumulation of toxins (although not highly potent), loss of fluids in the posterior gastrointestinal tract, and dysfunction of various organs. Death of fish was apparently due to a combination of these ill effects. / Graduation date: 1979

The bacterium Chlamydia trachomatis as well as the Human Immunodeficiency virus-1 (HIV-1) are sexually transmitted pathogens; both can infect monocytes/ macrophages and have an obligate intracellular replication cycle. It has been hypothesized that sexually transmitted infections (STIs), including genital Chlamydia, enhance HIV-1 transmission; yet, the underlying biological mechanisms remain unclear. The pathogen¡¯s common biology makes it possible that C. trachomatis and HIV mutually affect each other¡¯s replication cycle during monocyte/macrophage co-infection. To test this hypothesis we used two different bacteria strains in an in vitro HIV co-infection model: Latently virus-infected U1 promonocytes were either inoculated with C. trachomatis serovar D or serovar L2. It was found that serovar D, but not the LGV serovar L2, quickly and significantly reactivates integrated HIV-1 provirus. This reactivation depends on viable bacteria but seemingly neither on a microbial pathogen-associated molecular pattern (PAMP) nor on de novo gene expression by C. trachomatis. Hence, it could be triggered by a preformed protein that the bacterium translocates into the human cell. Because virus production occurs in Chlamydia-infected as well as Chlamydia-free cells and cannot be induced by conditioned culture medium, we propose a cell contact-dependent signal to U1 bystander cells. The HIV reactivation mechanism involves NF-kappaB activation but is independent of eukaryotic de novo protein translation. In summary, the findings might describe a novel Chlamydia-mediated HIV-1 reactivation mechanism from latently infected cells.

Thesis (M.P.H.)--University of Hong Kong, 2009. / Includes bibliographical references (p. 29-34).

Thesis (M. Phil.)--University of Hong Kong, 1987.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

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Studies were conducted to ascertain the effects of Ostertagia circumcincta infection in sheep. Three different levels of infection were used, 10,000 larvae, 60 1000 larvae and 120,000 larvae, and the criteria examined were hematocrit values, feed intake, dry matter digestibility, dry matter digested and weight gains. [...]

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