Historically, the primary belief has been that asthma is an atopic disease with the strongest risk factor for developing asthma being exposure to an allergen. However, researchers have begun to question that long held belief and are beginning to study other postnatal environmental factors such as stress. Research delving into maternal postnatal distress and the subsequent effects seen upon the developing neonatal immune system as it pertains to asthma has gained momentum. With that in mind, the focus of this research was 1) to determine if skin infections are more likely to be seen in young children who have been exposed to maternal distress, 2) to determine if skin infections in children from infancy to age 2 are associated with asthma, independent of atopic dermatitis, and 3) to determine if the association between early life skin infection and asthma was independent of recent stress biomarkers such as cortisol and dehydroepiandrostrone (DHEA). To meet the objectives listed above, the 1995 SAGE (Study of Asthma, Genes and the Environment) Manitoba birth cohort of 13980 children was used. Maternal postnatal distress, skin infection and atopic dermatitis in the infant, asthma at age 11 and other risk factors for asthma were derived from Manitoba’s health care databases. For objective 3, data on stress biomarkers (Cortisol/DHEA ratio) were obtained from the SAGE nested case-control study. Multivariable logistic regression analysis confirmed the first objective that skin infections (adj. OR 1.25, 95% CI 1.13-1.39) and or atopic dermatitis (adj. OR 1.46, 95% CI 1.26-1.70) seen in children from birth to age 2 could be used as indirect markers of stress. The second objective determined that children who exhibited an early skin infection, from birth to age two, were at an increased risk for developing asthma by age 11 independent of atopic dermatitis. However, this finding was dependent upon frequency of health care use. Those children that exhibited an early skin infection and had less than 24 health care visits over 7 years were 1.33 times (95% CI 1.01-1.75) more likely to acquire asthma by age 11 than those who did not have an early skin infection. Children with fewer health care visits were 1.44 times more likely to have asthma. The third objective was not met because the association between early skin infection and asthma was not independent of the Cortisol/DHEA ratio. However, the univariate results for skin infection in the nested case-control study were not significant. The findings of this thesis may be used by family physicians or paediatricians when looking for tangible markers that may indicate infants at risk for developing asthma by school age.

No description available.

The fungus Ascosphaera apis causes the disease chalk brood in larvae of the honey bee, Apis mellifera. Ascospores were recognised as the agents of disease, but the site of their germination to initiate infection had not been established. In this study larval surface cuticle was initially investigated as a possible site, but spores did not even activate here. Therefore, potential inhibitors of spore germination were studied, including water and chloroform washings of larval cuticle; 4 larval food constituents - pollen, honey, brood food, royal jelly; and a variety of medium-chain fatty acids a t concentrations of 1, 0.1 and 0. 01%. Royal jelly exhibited a severe inhibitory effect on all germination stages. Larvae were successfully infected by feeding them food Containing A. apis spores, both in vitro and in vivo. A histological study of infected larvae demonstrated germination of spores in the mid-gut lumen, followed by penetration of the peritrophic membrane and gut epithelium by developing hyphae; and subsequent invasion of larval tissues by mycelia. Various aspects of spore physiology were investigated. Spore activation and enlargement were shown to be independent of temperature within the ranges of 10 to 40°C and 25 to 40°C respectively, while germ-tube production was closely temperature related, only occurring between 25 and 37°C - with an optimum between 31 and 35°C . However, all 3 germination stages were found to be independent of environmental pH within the range of pH 5 to 7.8. Studies on the nutritional requirements for germination revealed the need for exogenous supplies of both a carbon and nitrogen source to support germ-tube production. The ‘spore-ball phenomenon’ was investigated and a supplementary amino acid source was identified . The etiology of chalk brood is discussed in the light of these findings.

No description available.

No description available.

Background and Aim: The applicability of internationally-accepted infection control guidelines in rural Indonesia is questionable due to differences in resources availability and local contexts. Infection control barriers specific to rural Indonesia therefore need to be identified to assist in developing targeted infection control programs that are resource- and context-appropriate at the institutional, regional and national levels. Methods: This mixed methods study of ten healthcare facilities (hospitals and clinics, public and private) in a rural Indonesian district, all with severely limited resources, explored clinical practices in four areas: intravenous therapy, antibiotic usage, instrument reprocessing and hand hygiene. The quantitative methods used included univariate, multivariate and survival analyses of primary and secondary clinical data. The qualitative methods included a grounded theory analysis of observations, short and in-depth interviews and focus group discussion data. These two components of the study were synthesised to ascertain the magnitude and underlying factors of healthcare-associated infection risks and barriers to infection control programs. Findings: Inappropriate clinical practices caused excessive and unrecognised risks of primary bloodstream infection, surgical site infection, blood borne virus infection, and the development and spread of multi-resistant bacteria. The four diverse clinical practice areas exhibited common and interwoven underlying factors, which were: healthcare workers?? inadequate clinical knowledge, a lack of managerial support, and cultural beliefs shared by the healthcare workers and community members that prevailed over evidence-based knowledge. Non-clinical factors from inside and outside the healthcare facilities were inter-related and cannot be separated from the ensuing clinical practice inadequacies. An analytical framework that categorises infection control barriers into clinical and non-clinical domains as well as internal and external factors is therefore proposed to ensure a comprehensive infection control program design. Conclusion: The current clinically-focused infection control programs are likely to have limited and temporary results in rural Indonesia due to barriers being in the main non-clinical in origin. An effective and sustainable infection control program needs to concurrently address basic clinical practice improvements and the underlying managerial, attitudinal and cultural barriers. This public health aspect of infection control is often neglected yet crucial for the success of any infection control program in rural Indonesia.

Infection with hepatitis C virus (HCV) causes significant morbidity and mortality. An understanding of the factors associated with both acquisition and clearance of HCV infection is critical to prevention strategies including vaccine development. Although research in the prison environment is logistically challenging, inmates are a premier risk group. Accordingly, a prospective cohort study of prisoners with monthly sampling for HCV viraemia was undertaken to assess the incidence of, and risk factors for, infection; and to assess the natural history of infection when detected by viraemia. The incidence of infection was 8 per 100 person years, with the incidence of "high risk" and "possible" HCV transmission risk events being 61 and 210 per 100 person years respectively. The first case of HCV infection in prison with tattooing as the probable route of acquisition was reported. A novel phenotype of HCV infection with HCV viraemia and subsequent clearance without the development of symptoms, biochemical hepatitis or seroconversion on HCV specific enzyme immunoassay (EIA), despite more than one year of follow-up, was reported. HCV-specific cell mediated immune responses were detected in the subjects analysed. These subjects also had indeterminate HCV serological responses directed against non-structural proteins detected on a recombinant immunob10t assay (RIBA) that were stable over time and typically predated HCV viraemia. The prevalence of such responses ranged from 29-79% in other relevant cohorts, including injecting drug users (IDUs) and multiply-transfused patients with thalassaemia. The antibody response against the non-structural protein, NS5 was the most reproducible. This reactivity was blocked in 57% of subjects when sera were pre-incubated with recombinant HCV proteins, suggesting HCV-specificity. A case-control study was undertaken to examine whether such responses predicted protection from "classical" HCV infection with EIA seroconversion. Cases that developed HCV viraemia and EIA seroconversion were more likely to have these responses at baseline (when aviraemic) than controls, demonstrating that they do not protect against acute infection. However, the rate of viral clearance in subjects with indeterminate RIBA responses that subsequently developed acute infection and were followed for viral clearance was high (88%), suggesting that such subjects have immune responses that are associated with viral clearance.

Thesis (M.S. - Microbiology and Immunology)--University of Arizona, 1985. / Includes bibliographical references (leaves 54-59).

Thesis (M.S. - Nutrition and Food Science)--University of Arizona, 1986. / Includes bibliographical references (leaves 58-62).

Thesis (M.Nurs.)--University of Hong Kong, 2008. / Includes bibliographical references (p. 96-107)