Background. Medical imaging has played an important role in the diagnosis, progress monitoring and follow-up of most disease entities, in particular chest infections. The emergence of a novel chest disease poses an immediate challenge to the pillars of imaging, namely chest radiography and computed tomography. The characteristic imaging appearances, differential diagnoses and diagnostic pitfalls need to be established for correct diagnosis and appropriate management. The sensitivity and utility of the different imaging modalities will also need to be addressed. / In the event of an outbreak or epidemic, these challenges are made more difficult by an overwhelming number of patients and limited resources. In March 2003, we were faced with such a situation in our institution and the disease was later termed Severe Acute Respiratory Syndrome (SARS). / Patients in Hong Kong were treated with a combination of an antiviral agent and corticosteroids in addition to respiratory support. The majority of patients improved with treatment, although between 20--36% required treatment in an intensive care unit. / Problems and importance. This novel disease of high infectivity, morbidity and mortality posed a major threat to public health and a challenge to health authorities both locally and internationally. With regard to medical imaging, the following research questions were identified: (1) What are the imaging signs of this new disease? (2) Does chest imaging provide a high degree of sensitivity for diagnosing the infection? (3) Are the imaging signs disease-specific or are they similar to other pathology? (4) Does the progressive evolution of the imaging appearance correlate with the clinical status of the patient? (5) Could the imaging appearance be useful for predicting the final outcome? (6) Are there complications that require detection by imaging? / The lung parenchyma is the main site of infection and the resultant microscopic pathology included: pulmonary exudate, sequestration of macrophages, diffuse alveolar damage, proliferation of epithelial cells and hyaline membrane formation. Macroscopic features include alveolar consolidation in the early stages and later, organizing pneumonia or bronchiolitis obliterans organizing pneumonia. / These answers to these questions are essential to our understanding of the disease and to increase our diagnostic ability. (Abstract shortened by UMI.) / This newly emerged disease is a respiratory infection with a high morbidity/mortality and was found to be caused by a coronavirus (SARS CoV). By the end of the outbreak a total of 8098 probable cases of infection were reported worldwide, with a mortality rate of 9.6% (774 deaths). Hong Kong was one of the hardest hit regions, totaling 1755 probable cases of infection and 299 deaths by the end of the outbreak. / Antonio Gregory Ernest. / "September 2005." / Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 3745. / Thesis (M.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 245-258). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / School code: 1307.

The objectives of this research study are: 1. To probe into the widespread period of severe acute respiratory syndrome. 2. To study on this highly contagious and rapid spread of this new kind of disease At the time when nearby emergency department of medical center breaks out a suspicion of nasocomial infection. First, our emergency department immediately formed a strict fever screening station. After comparing the outcome of the prevention and spreading of this disease by the set-up of the emergency fever station between the central and southern medical institution. The research period was from May 15, 2003to July 15, 2003. Our research targets made by the emergency fever station were around 3730 patients with a random selection of 300 cases. This research uses the structure of fever screening measurement questionnaires to gather information and then adapted the EP1-INFO 10.0 version of statistical analysis. The results of the research are as follows: 1. Chief complaint of sore throat (38.3%) and fever (17%) fitted to the clinical symptoms of SARS. In relation to SARS before and after the spread of the disease, there are still other complaints such as the gastrointestinal system (18.7%) and cardiovascular disease (16.7%) that showed no obvious difference. 2. During the period of emergency fever screening station, an additional 50% of manpower are being arranged to screen probable or non-probable affected cases. (from the 300 randomly selected cases) 3. There are no obvious difference showed after comparing the outcome of the prevention and spreading of this disease by the set-up of the emergency fever center between the central and southern medical institution. 4. After tallying the number of doctors and nurses participated in screening procedure and number of non-medical staff developed similar symptoms to SARS, we can see the result of total number of medical staff from the emergency fever screening station that can successfully control the spread and prevention of the disease, making it the standard and model in the prevention and control of other communicable disease in the future. Key words: Severe acute respiratory syndrome, fever screening station, emergency room, emergency task force

An investigation of the distribution of porcine reproduction and respiratory syndrome virus (PRRSV) and factors associated with the presence of PRRSV in Ontario from 2004 – 2007 was conducted. Surveys on the presence of clinical signs associated with PRRS, management practices, animal suppliers, and herd location were administered to the managers of 458 PRRSV positive herds and 61 PRRSV negative herds. Open reading frame (ORF) 5 of the PRRSV genome was sequenced from herds with PRRSV. PRRSV positive herds were compared to PRRSV negative herds. Management practices associated with being PRRSV positive were: not washing animal- and feed-delivery vehicles, feed-delivery and animal-transport vehicles visiting multiple herds at one time, allowing a truck driver to enter the barn, not requiring visitors to shower prior to farm entry, and not utilizing all-in all-out flow in gilt and finisher barns. Specific PRRSV restriction fragment length polymorphism (RFLP) genotypes of the ORF5 gene were compared with clinical signs. Herds with RFLP type ‘1-undetermined-4’, ‘1-undetermined-2’ and 1-3-4 were associated with clinical signs in sows and 2-6-2 was associated with finisher mortality compared to herds with vaccine virus. Additionally, genotypes 1-3-4 and 1-8-4 increased in frequency during this study. The between-herd PRRSV similarity of genome and clinical signs were compared. Abortions and stillbirths were associated with similarity in genetic sequences between herds. This relationship did not extend to those herds where vaccine virus was identified. Patterns in space and time of herds with different RFLP types of PRRSV were investigated after accounting for ownership. There was weak evidence to suggest local spread the genotype 1-3-4. The association between genetic similarity and proximity in space, time, ownership, animal, and semen suppliers was tested. Significant correlation was detected for distances up to 30 km. After controlling for ownership, only small associations between breeding stock and semen suppliers and genetic similarity of PRRSV were found. The spread of PRRSV among herds in Ontario cannot be attributed to any one factor. However, similarity in ownership between herds was a key variable indicating that movement of animals, personnel, and vehicles among herds must be measured in future investigations of PRRSV dynamics. / Ontario Pork and the Canada-Ontario Research and Development (CORD) Program and the OMAFRA/University of Guelph agreement

Thesis (M.S.)--University of Hawaii at Manoa, 2006. / Includes bibliographical references (leaves 62-77). / ix, 77 leaves, bound ill. (some col.), maps (some col.) 29 cm

Thesis (Ph. D.)--University of Missouri-Columbia, 2005. / "December 2005" The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Vita. Includes bibliographical references.

A host can adopt two strategies when facing infection: resistance, where host immune responses prevent or reduce pathogen replication; or tolerance, which refers to all mechanisms that reduce the impact of the infection on host health or performance. Both strategies may be under host genetic control, and could thus be targeted for genetic improvement. Although there is ample evidence of genetic variation in resistance to infection, there is limited evidence to suggest that individuals also differ genetically in tolerance. Furthermore, although resistance and tolerance are typically considered as alternative host defense mechanisms, relatively little is known about the genetic relationship between them and how they change together over time and jointly determine infection outcome. In this thesis, two datasets from experimental challenge infection experiments were considered for investigating tolerance genetics: Porcine Reproductive & Respiratory Syndrome (PRRS), an endemic viral disease which causes loss of growth and mortality in growing pigs; and Listeria monoctyogenes (Lm), a bacterium which causes food-borne infections in mammals. The two datasets differed substantially in size and genetic structure; the PRRS dataset consists of thousands of records from outbred commercial pig populations, whereas the Listeria dataset comprises much fewer records from genetically diverse highly inbred strains of a mice as a model species. The aims of this thesis were to: 1) Identify if genetic variation in host tolerance to infection exists, with case studies in PRRS and listeria, using conventional reaction-norm methodology; 2) Identify if host tolerance, along with resistance, changes longitudinally as infection progresses; 3) Identify whether the WUR genotype is associated with tolerance slope; 4) Analyse the dynamic relationship between host performance and pathogen load over the time-course of infection by examining the relationship at different stages of infection using GWAS; 5) Develop novel trajectory methodology to offer insight into health-infection dynamics, and identify whether there is genetic variation in trajectories; 6) Develop novel trajectory-derived phenotypes that analyse changes in host performance with respect to changes in pathogen load, as an alternative to tolerance, and identify whether genetic variation exists. This study found that conventional reaction-norm methodology is limited to capture genetic variation in tolerance in outbred populations without measures of performance in the absence of infection. However, by utilising repeated longitudinal data on the same dataset, stages of infection (early, mid and late) were defined for each individual, based on host pathogen load. Using these stages of infection, genetic variation in tolerance was identified over all stages of infection and at mid to late stage of infection. Genetic correlation between resistance and tolerance was strong and positive over all stages of infection, and evidence suggested that resistance and tolerance may be under pleiotropic control. Furthermore, this research found that genetic correlations between resistance and growth changed considerably over time, and that individuals who expressed high genetic resistance early in infection tended to grow slower during that time-period, but were more likely to clear the virus by late stage, and thus recover in growth. However, at mid-late stage of infection, those with high virus load also had high growth, indicating potential epidemiological problems with genetic selection of host resilience to infection. Furthermore, genome wide association studies for pathogen load and growth associated with different stages of infection did not identify novel genetic loci associated with these traits than those previously reported for the whole infection period. By adopting conventional methodology, this study found genetic variation in tolerance of genetically diverse mouse strains to Lm and pigs to PRRS, despite statistical problems. The relationship between resistance and tolerance indicated that both traits should be considered in genetic selection programs. By adopting novel trajectory analysis, this study demonstrated that level of expression of resistance and tolerance changed throughout the experimental infection period and, furthermore, that expression of resistance, followed by tolerance, determined survival of infection. Survivors and non-survivors followed different infection trajectories, which were partially determined by genetics. By deriving novel phenotypes from trajectories that explained changes in growth in relation to change in pathogen load at specific time points, and applying these to the PRRS data, this study did not identify genetic variation in these phenotypes. The genetic signal in these phenotypes may have been masked by the fact that individuals were likely at different stages of infection. In summary, this study has shown that genetic improvement of tolerance, in addition to resistance may be desirable, but could be difficult to achieve in practice due to shortcomings in obtaining accurate and unbiased tolerance estimates based on conventional reaction-norms. Infection trajectories have proven to be a promising tool for achieving an optimally timed balance between resistance and tolerance, but further work is needed to incorporate them in genetic improvement programs.

Doctor of Philosophy / Diagnostic Medicine/Pathobiology / Raymond R. R. Rowland / Severe combined immunodeficiency (SCID) is a rare group of inherited disorders characterized by defects in both humoral and cellular immune functions. Naturally occurring SCID has been first described in humans in the 1960s and subsequently identified in horses, mice, and dogs, but never before in pigs. Affected animals are characterized by having loss of functional B and T lymphocytes, and in some cases natural killer (NK) cells, but normal numbers of monocytes, granulocytes, and megakaryocytes. As a result, affected animals fail to produce antibodies and succumb to common disease pathogens after circulating maternal antibodies decay. SCID models are extremely valuable for the understanding of molecular mechanisms of immunological processes during viral and bacterial diseases, cancer, and autoimmunity. SCID mice are widely used as the current model; however, the relevance of the murine SCID model to human and veterinary immune research is limited and there is an increasing need for a more representative model of SCID is imperative. We describe the gross, microscopic, and immunophenotypic characteristics of a line of Yorkshire pigs having naturally occurring SCID. Affected pigs lack T and B lymphocytes, but display circulating NK cells, fail to produce antibodies to viral infection, and lack cell-mediated response to tumor xenotransplants. We also describe response of SCID pigs to porcine reproductive and respiratory syndrome virus (PRRSV). PRRSV is the most devastating virus in swine industry, causing losses of billions of dollars annually. Understanding the immunopathogenesis of the disease is imperative in order to develop strategies to combat this devastating virus. PRRSV infected-SCID pigs failed to develop lesions of PRRSV infection, demonstrating the significant role of the adaptive immunity to PRRSV infection. Finally, we describe the preliminary results of the adoptive transfer of purified CD3⁺ T lymphocytes to SCID pigs from SLA-II matched wild-type littermates, with the objective of establishing a porcine model for the study of T cell immunopathogenesis with viral diseases.

Magister Scientiae (Medical Bioscience) - MSc(MBS) / Coronaviridae family is composed of a number of ribonucleic acid (RNA)-containing viruses currently classified into two genera, the coronavirus and torovirus. The family is classified together with the Arteviridae in the order Nidovirales. Coronaviruses are enveloped single stranded positive sense RNA viruses about 80-160 nm in diameter. The coronavirus is, as in the case of all positive sense RNA virus, a messenger, and the naked RNA is infectious. The 5′-two thirds of the genome encodes for a polyprotein that contains all the enzymes necessary for replication, whereas the 3′-one third encodes for all the structural proteins that mediate viral entry into the host cell. The structural proteins include spike (S), envelope (E), membrane (M) and nucleocapsid (N) proteins.Nucleocapsid protein is one of the most crucial structural components of coronaviruses;hence major attention has been focused on characterization of this protein. Some laboratories have demonstrated that this protein interferes with different cellular pathways, thus implying it to be a key regulatory component of the virus (Zakhartchouk, Viswanathan et al. 2005). Furthermore, it has been shown that severe acute respiratory syndrome (SARS)-N protein interacts with cellular proteins, including cyclophilin A (CypA), heterogenous nuclear ribonucleoprotein (hnRNP) A1, human ubiquitin-conjugating enzyme, cyclin dependent kinase (CDK)-cyclin complex protein, Ikappaßalpha (IkBα), cytochrome (Cyt) P450 etc. For the purpose of this study, the focus is based on CypA interaction with human coronavirus (HCoV) NL63-N protein. These interactions might play a role in the pathology of HCoV-NL63. Using glutathione-S-transferase (GST), the interaction of CypA with the nucleocapsid protein can be clearly demonstrated to be direct and specific. Since the N protein is involved in viral RNA packaging to form a helical core, it is suffice to say that both NL63-N and CypA are possibly within the HCoV-NL63 replication/transcription complex and NL63-N/human CypA interaction might function in the regulation of HCoV-NL63 RNA synthesis. In addition, the results will demonstrate that HCoV-NL63-N has only a specific domain for interacting with CypA.

Doctor of Philosophy / Department of Diagnostic Medicine/Pathobiology / Raymond R. Rowland / Severe acute respiratory syndrome (SARS) is caused by an enveloped, positive-stranded RNA virus, the SARS coronavirus (SARS-CoV). Coronaviruses along with the arteriviruses are placed in the order, Nidovirales. Even though nidovirus replication is restricted to the cytoplasm, the nucleocapsid protein (N) of several coronaviruses and arteriviruses, localize to the nucleolus during infection. Confocal microscopy of N protein localization in Vero cells infected with the SARS-CoV or transfected with the SARS-CoV N gene failed to show presence of N in the nucleoplasm or nucleolus. Recombinant N remained cytoplasmic after the addition of leptomycin B (LMB), a drug that inhibits nuclear export. SARS-CoV N possesses a unique lysine-rich domain, located between amino acids 369-389, which possesses several nuclear localization signal (NLS) and nucleolar localization signal (NoLS) motifs. A chimeric protein composed of the 369-389 peptide substituted for the NLS of equine infectious anemia virus (EIAV) Rev protein (ERev) showed no nuclear localization activity. Three negatively charged amino acids, located at positions 372, 377 and 379 in SARS-CoV N were hypothesized to play a role in the loss of nuclear targeting. Substitution of aspartic acid-372 with alanine restored nuclear localization to the chimeric protein. A full-length recombinant SARS-N protein with the alanine-372 substitution localized to the nucleus. Therefore, the presence of an aspartic acid at position 372 is sufficient to retain N in the cytoplasm The mechanistic basis for how aspartic acid-372 interrupts nuclear transport is unknown, but may lie in the electrostatic repulsion with negatively charged amino acids located within the NLS binding pocket of importin-alpha.

Porcine reproductive and respiratory syndrome virus (PRRSV) is arguably the most economically-important swine pathogen. As the emergences of novel virulent strains of PRRSV continue to occur worldwide, rapid vaccine development is the key for effective control of ongoing PRRSV outbreaks. With the availability of the PRRSV reverse genetics systems, rapid vaccine development against PRRSV through the manipulation of the reverse genetics becomes feasible. To facilitate the vaccine development effort and study of PRRSV genes, we first established a DNA-launched infectious clone of the passage 14 PRRSV strain VR2385, pIR-VR2385-CA, and identified a spontaneous 435-bp deletion in the nsp2 gene. To characterize the biological and pathological significance of this nsp2 deletion, we restored deleted nsp2 sequence back to pIR-VR2385-CA and constructed another clone pIR-VR2385-R. VR2385-CA and VR2385-R were successfully rescued in vitro. The results from this study indicates that the spontaneous nsp2 deletion plays a role for enhanced PRRSV replication in vitro but has no significant effect on the pathogenicity of the virus. With the availability of the DNA-launched infectious clone of PRRSV, we successfully applied the molecular breeding approach to rapidly attenuate PRRSV. The GP5 envelope genes of 7 genetically divergent PRRSV strains and the GP5-M genes of 6 different PRRSV strains were molecularly bred. DS722 with shuffled GP5 genes and DS5M3 with shuffled GP5-M genes, were successfully rescued in vitro and shown to be attenuated both in vitro and in vivo. Furthermore, DS722, but not DS5M3, still elicit similar protection against PRRSV challenge as its parental virus. This study reveals a unique approach through DNA shuffling of viral envelope genes to attenuate a positive-strand RNA virus. We subsequently utilized the novel synthetic attenuated virus engineering (SAVE) approach to attenuate PRRSV. The GP5 and nsp9 genes of PRRSV were codon-pair deoptimized with the aid of a computer algorithm. SAVE5 and SAVE9 with deoptimized GP5 gene and SAVE9 with deoptimized nsp9 gene, were successfully rescued and shown to be attenuated in vitro. An in vivo pathogenicity study indicated the attenuation of SAVE5 virus in vivo. The results have important implications for rapid vaccine development against PRRSV and other important viruses. / Ph. D.