Copies of author's previously published articles contained in back cover pocket. / Bibliography: leaves 129-152. / xiv, 152, [60] leaves, [28] leaves of plates : ill. (some col.) (some folded) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Examines hepadravirus and HDV replication and gene expression with particular emphasis on the block(s) preventing HBV infection invitro, the extent of the helper function provided by HDV by HBV and the mechanism of HDV RNA replication. / Thesis (Ph.D.)--University of Adelaide, Depts. of Microbiology and Immunology, 1992

Improved methods for the in situ hybridisation detection of messenger RNA ( mRNA ) in sections of liver tissue, were derived by use of an experimental system. This involved the use of tritiated-poly ( dT ) probes to detect poly ( A ) sequences attached to the 3 ' end of mRNA in sections of mouse liver that had been processed in various ways. The improved - methods were applied to the detection of hepatitis B virus ( HBV ) - and hepatitis delta virus ( HDV ) - RNA. In situ hybridisation and immunostaining techniques were then applied to studies of the pathogenesis of HBV and duck hepatitis B virus ( DHBV ) infection. In situ hybridisation studies of liver biopsy tissue from HBV - infected immunosuppressed renal transplant patients demonstrated an anatomical association between piecemeal necrosis and HBV replication at the cellular level in some patients. However, widespread replicative infection of hepatocytes also occurred in some patients in the presence of normal hepatocyte morphology and mild inflammatory changes indicating that at the cellular level virus replication was not necessarily a direct cytopathic process. These findings supported the view that hepatocyte Injury may : ( i ) result from immune - mediated damage directed against cells undergoing replicative, but not restricted infection ; ( ii ) eliminate cells undergoing replicative infection and favour clonal regeneration of cells undergoing restricted infection. Localisation of interferon - alpha ( IFN - alpha ) expression in liver tissue chronically infected with HBV and HDV, identified mononuclear cells and fibroblasts ( but not hepatocytes ) as the main producers of IFN - alpha. IFN - alpha - positive cells were associated with areas of liver tissue containing cells supporting virus replication and exhibiting the greatest degree of liver damage, suggesting that locally produced IFN - alpha may be a natural regulator of virus replication in chronic liver disease. Experimental DHBV infection of Pekin - Aylesbury ducks showed that virus inoculated either intravenously or intraperitoneally, gained access to randomly distributed hepatocytes without first replicating in other cell types in the liver. Virus was seen to disseminate to contiguous cells following anatomical boundaries by the third day post - inoculation. Markers of DHBV infection in liver and serum showed reproducible kinetics, and duck hepatocytes in this system appeared to be highly permissive as large amounts of DHBV DNA and DHBsAg were produced intracellularly without the development of ongoing cytopathology. Hepatocytes were the major cell type responsible for early significant DHBV replication, in contrast to pancreas, kidney, spleen and circulating mononuclear cells where significant levels of infection were detected only after the first week of infection and the onset of viraemia. / Thesis (Ph.D.)--Department of Microbiology and Immunology, 1989.

Improved methods for the in situ hybridisation detection of messenger RNA ( mRNA ) in sections of liver tissue, were derived by use of an experimental system. This involved the use of tritiated-poly ( dT ) probes to detect poly ( A ) sequences attached to the 3 ' end of mRNA in sections of mouse liver that had been processed in various ways. The improved - methods were applied to the detection of hepatitis B virus ( HBV ) - and hepatitis delta virus ( HDV ) - RNA. In situ hybridisation and immunostaining techniques were then applied to studies of the pathogenesis of HBV and duck hepatitis B virus ( DHBV ) infection. In situ hybridisation studies of liver biopsy tissue from HBV - infected immunosuppressed renal transplant patients demonstrated an anatomical association between piecemeal necrosis and HBV replication at the cellular level in some patients. However, widespread replicative infection of hepatocytes also occurred in some patients in the presence of normal hepatocyte morphology and mild inflammatory changes indicating that at the cellular level virus replication was not necessarily a direct cytopathic process. These findings supported the view that hepatocyte Injury may : ( i ) result from immune - mediated damage directed against cells undergoing replicative, but not restricted infection ; ( ii ) eliminate cells undergoing replicative infection and favour clonal regeneration of cells undergoing restricted infection. Localisation of interferon - alpha ( IFN - alpha ) expression in liver tissue chronically infected with HBV and HDV, identified mononuclear cells and fibroblasts ( but not hepatocytes ) as the main producers of IFN - alpha. IFN - alpha - positive cells were associated with areas of liver tissue containing cells supporting virus replication and exhibiting the greatest degree of liver damage, suggesting that locally produced IFN - alpha may be a natural regulator of virus replication in chronic liver disease. Experimental DHBV infection of Pekin - Aylesbury ducks showed that virus inoculated either intravenously or intraperitoneally, gained access to randomly distributed hepatocytes without first replicating in other cell types in the liver. Virus was seen to disseminate to contiguous cells following anatomical boundaries by the third day post - inoculation. Markers of DHBV infection in liver and serum showed reproducible kinetics, and duck hepatocytes in this system appeared to be highly permissive as large amounts of DHBV DNA and DHBsAg were produced intracellularly without the development of ongoing cytopathology. Hepatocytes were the major cell type responsible for early significant DHBV replication, in contrast to pancreas, kidney, spleen and circulating mononuclear cells where significant levels of infection were detected only after the first week of infection and the onset of viraemia. / Thesis (Ph.D.)--Department of Microbiology and Immunology, 1989.

京都大学 / 新制・課程博士 / 博士(生命科学) / 甲第23440号 / 生博第461号 / 新制||生||61(附属図書館) / 京都大学大学院生命科学研究科統合生命科学専攻 / (主査)教授 野田 岳志, 教授 朝長 啓造, 教授 千坂 修 / 学位規則第4条第1項該当 / Doctor of Philosophy in Life Sciences / Kyoto University / DFAM

<p>Autophagy is a cellular process in which cytoplasmic material is lysosomally degraded into its basic components. The primary functions of this process are cellular recycling and stress mitigation however it also has roles in both viral pathogenesis and tumourigenesis. Beclin1 is a key mediator of autophagy and is involved in its initiation. In an attempt to examine the effects of enhanced autophagy in the context of oncolytic VSV infection, a VSV mutant (ΔM51) expressing Beclin1 was constructed and characterized. It was determined through western blot analysis of autophagy marker LC3, that while VSV infection enhanced autophagy in infected cells, Beclin1 expression resulted in a transient increase in autophagy followed by markedly reduced levels of autophagy at mid to late time points. Still, Beclin1expression, either directly or possibly through altering the kinetics of VSV induced autophagy, enhanced the pathogenesis of VSV<em> </em>in some cell lines <em>in vitro</em>. However examination of the <em>in vivo</em> pathogenesis of VSV-Belcin1 elicited no differences from that of the parental virus. Despite enhanced pathogenesis in CT26 cells <em>in vitro</em>, VSV-Beclin1 displayed no improvement in the oncolysis of CT26 tumours <em>in vivo</em>, compared to VSV-GFP. It is hoped that the conclusions drawn from this study will help direct future research aimed at exploring the relationship between autophagy and VSV pathogenesis as well as future attempts to arm VSV with the intent of augmenting its oncolytic potential.</p> / Master of Science (MSc)

Doctor of Philosophy / Diagnostic Medicine/Pathobiology / Raymond R. R. Rowland / Emerging viral diseases cause significant and widespread economic losses to U.S. swine production. Over the last 25 years, porcine reproductive and respiratory syndrome virus (PRRSV), porcine circovirus type 2 (PCV2) and porcine epidemic diarrhea virus (PEDV) have emerged or re-emerged, costing the industry billions through increased mortality and clinical or subclinical reductions in growth. Nursery pigs are greatly affected by these viruses due to high susceptibility to primary and secondary infections after weaning. However, clinical disease occurs in only a subpopulation of infected pigs and can vary drastically from sudden death to poor growth performance. This thesis documents a series of 4 studies where nursery pigs were challenged with either PRRSV/PCV2 or PEDV; the associations between clinical outcome and several factors affecting viral pathogenesis were investigated. In the first study, the administration of PRRS modified live virus vaccine prior to co-challenge with PRRSV/PCV2 was shown to protect against PRRS but enhance PCV2 replication and pathogenesis. This study provides insight into the role that PRRS vaccination has in both the control and potentiation of clinical disease. In the second study, microbial populations were compared between pigs with the best and worst clinical outcome following PRRSV/PCV2 co-infection. Increased fecal microbiome diversity was associated with improved clinical outcome; however, worst clinical outcome pigs had prolonged and greater virus replication, highlighting the host response to viral challenge as a primary determinant of clinical outcome. In the third study, 13 clinical phenotypes were compiled for >450 pigs after PRRSV/PCV2 co-infection. Duration of dyspnea and the presence of muscle wasting had the strongest associations with reduced weight gain. This study highlights the opportunity to improve animal welfare and production through improvements in clinical health. In the fourth study, clinical disease was mild to moderate and occurred within the first week after pigs were challenged with PEDV. However, PEDV was detected weeks after clinical disease had resolved and may implicate nursery pigs as an important source of viral carriage and transmission. Overall, the goal of this thesis was to develop models for understanding the impact of emerging and re-emerging viruses to improve recognition and control of disease.

The biology and epidemiology of bovine herpesvirus 2 (BoHV-2), the agent of bovine herpetic mammillitis (BHM), remain largely unknown. Thus, the present study aimed at addressing selected aspects of BoHV-2 epidemiology and pathogenesis in sheep and guinea pigs. A serological survey for BoHV-2 antibodies in 2.213 samples from cattle > 24-months-old from 136 counties of seven different mesoregions of Rio Grande do Sul (RS) revealed an overall prevalence of 24.5% (543/2.213). These results demonstrate that BoHV-2 infection is widespread among cattle in RS, and potentially involved in cases of mammillitis frequently described in dairy cows. A second experiment was conducted to characterize the latent BoHV-2 infection in a sheep model. Lactating ewes inoculated with BoHV-2 in the skin of the udder shed virus for up to five days, developed mammillitis and seroconverted. However, attempts to reactivate latent infection by dexamethasone (Dx) administration at day 40 post infection (pi) failed. Nevertheless, viral DNA was detected by PCR in several nerve ganglia and/or regional lymph nodes (LNs) of all animals at day 40 post-reactivation (pr). Lambs previously inoculated with BoHV-2 in the nose also harbored latent viral DNA in trigeminal ganglia, tonsils and regional LNs. These results demonstrated that BoHV-2 establishes latent infection in nerve ganglia and in regional lymphoid tissues, yet virus reactivation is not easily achieved by standard protocols used for other alphaherpesvirus. A third experiment was conducted to evaluate guinea pigs (Cavia porcellus) as an experimental model to study the biology of BoHV-2 infection. Weanling (30-40 daysold) guinea pigs inoculated into the genital area and over the skin of the udder and teats with a viral suspension developed moderate to severe clinical signs, noticeably more pronounced in the genital area. Infectious virus was recovered from swabs collected between days 3 and 7 from genital area (8/12) and less frequently (1/12) from teat skin. All animals seroconverted to BoHV-2 developing neutralizing titers from 16 to 128 at day 30 pi. Histological examination of skin biopsies collected from genital lesions showed intranuclear inclusion bodies and perivascular infiltrates composed by lymphocytes and plasmocytes. PCR examination of tissues collected from animals euthanized at day 35 pi revealed the presence of latent viral DNA in nerve ganglia and LNs. Dx administration at day 35 pi was followed by mild recrudescence of genital disease in some animals, yet virus isolation and/or seroconversion which are usually taken as indicators of virus reactivation were not observed. These results show that guinea pigs may be used as models to study BoHV-2 acute and latent infection and confirm that BoHV-2 reactivation is not easily achieved by using the standard protocols for other alphaherpesviruses. Taken together, these results demonstrate that both sheep and guinea pigs are suitable animal models for BoHV-2 infection. / A biologia e a epidemiologia da infecção pelo herpesvírus bovino tipo 2 (BoHV-2), agente da mamilite herpérica bovina, são pouco conhecidas. Com isso, o presente estudo teve como objetivos elucidar alguns aspectos da epidemiologia e estudar a patogenia da infecção pelo BoHV-2 em ovinos e cobaias. Um estudo sorológico pesquisando anticorpos para o BoHV-2 em 2.213 amostras de bovinos com mais de 2 anos, provenientes de 136 municípios distribuídos em 7 mesoregiões do Rio Grande do Sul (RS), determinou uma soroprevalência de 24,5% (543/2.213). Os resultados demonstram que o BoHV-2 está disseminado no rebanho bovino no RS, com potencial envolvimento em casos de mamilite freqüentemente relatados em rebanhos leiteiros. Um segundo experimento visou caracterizar a infecção latente em ovinos, propostos como modelo experimental. Ovelhas lactantes inoculadas com o BoHV-2 na pele do úbere excretaram o vírus por até 5 dias, desenvolveram mamilite e soroconverteram. Entretanto, a tentativa de reativar a infecção latente pela administração de dexametasona (Dx) no dia 40 pós-infecção (pi) não resultou em reativação. Não obstante, o DNA viral latente foi detectado por PCR em gânglios neurais e/ou em diversos linfonodos (LNs) de todos os animais no dia 40 pós reativação (pr). Cordeiros que haviam sido inoculados com o BoHV-2 pela via nasal igualmente albergavam o DNA viral latente nos gânglios trigêmeos, tonsilas e LNs regionais. Esses resultados demonstram que o BoHV-2 estabelece infecção latente em gânglios neurais e tecidos linfóides regionais, embora a reativação viral não seja facilmente obtida com os protocolos usados em outros alfaherpesvírus. Um terceiro experimento foi realizado para validar cobaias (Cavia porcellus) como modelo experimental para estudo da biologia da infecção com o BoHV-2. Cobaias lactentes (30- 40 dias) inoculadas com o BoHV-2 nas regiões genital e intra-dérmico no tetos e úbere desenvolveram sinais clínicos moderados a severos, notadamente mais pronunciados na região genital. O vírus foi isolado de suabes coletados entre os dias 3 e 7 pi da região genital (8/12) e em menor freqüência da região dos tetos (1/12). Todos os animais soroconverteram para o BoHV-2, apresentando títulos de anticorpos neutralizantes entre 16 e 128 no dia 30 p.i. A análise histológica de biópsias de pele coletada de lesões revelou corpúsculos de inclusão e infiltrado linfocitário e plasmocitário perivascular. PCR realizada com DNA total extraído dos tecidos coletados no dia 35 pi revelou a presença de DNA viral latente em gânglios neurais lombo-sacrais e LNs regionais. A administração de Dx no dia 35 pi cursou com recrudescência clínica na região genital, porém não foram detectados excreção viral nem soroconversão, indicadores de reativação da infecção latente. Estes resultados demonstram que cobaias podem ser usados como modelo para a infecção aguda e latente pelo BoHV- 2, e confirmam que a reativação viral não é facilmente obtida pelo uso de protocolos usuais para outros alfaherpesvírus. Em conjunto, os resultados demonstram a utilidade de ovinos e cobaias como modelo experimental para a infecção pelo BoHV-2.

No description available.

[Truncated abstract] Ross River virus (RRV) causes the most common arboviral disease in Australia, with approximately 5000 new cases reported each year, making this virus a major public health concern. The aim of this thesis was to link results from virological, pathogenesis and epidemiological studies to further define RRV disease in the south-west (SW) of Western Australia (WA), a region of endemic and epizootic RRV activity. A crosssectional seroprevalence study was used to show that 7.8 percent of SW communities were seropositive to RRV, comparable to other regions of Australia with similar temperate climates to the SW . . . RRV-specific IgM antibodies were found to persist for at least two years following RRV infection. A murine model was used to conclusively show differences in pathogenesis between RRV genotypes, the SW and northern-eastern (NE) genotypes, which are known to circulate throughout Australia. The SW genotype, unique to the SW of WA induced only poor neutralising antibody production and nonneutralising antibodies after the acute phase of infection. In comparison, the NE genotype which currently predominates in mosquito populations in the SW of WA, induced the most efficient neutralising antibody response and consequently produced the mildest disease in the mouse. These data in the mouse suggest that the infecting genotype will mostly likely influence disease outcome in humans and could at least partially explain why more severe and persistent disease has been reported from the SW of WA. Collectively, results from this thesis provide an important benchmark against which future investigations into BFV and RRV diseases can be measured.