The existence, probability and control measures of airborne infections have been widely discussed for centuries. Although public belief regarding airborne infection kept on altering throughout the entire history of medicine and is still controversial, many airborne transmission experiments and airborne infection outbreak analyses have been carried out. Different airborne transmission models have been built and various airborne control measures have been evaluated. One of the major knowledge gaps obstructing applications of some airborne control measures in clinical practices and public applications is that there is a lack of evidence in proving the effectiveness of such measures. Ventilation as an important airborne infection control method can be achieved by opening windows, or increasing the outdoor air supply rate in mechanical ventilation systems or indirectly by using filters and ultraviolet equipments. However the applications of ventilation in infection control were largely restricted to isolation rooms rather than regarded as a public control measure. In this study we focus on evaluating the effectiveness of ventilation as a community measure. Results, therefore, can provide evidence for using ventilation as a public health measure for controlling respiratory diseases transmitted by the airborne route or multi-routes. Two mathematical modeling approaches (deterministic model and social network model) are adopted to estimate different airborne diseases outbreaks with a focus on ventilation and a corresponding analysis of their relative effectiveness compared with other public health measures. A comprehensive understanding of detailed control strategies (including both engineering and public health control) will be achieved through gradually complicated and realistic models. It’s commonly believed that many respiratory infections are transmitted through multiple routes including airborne, droplet-borne and contact routes. Hence the effectiveness of airborne control measures was doubted when the airborne route was not dominant. Therefore, we developed a model to simulate partially airborne transmitted diseases outbreaks and evaluated the relative effectiveness of ventilation when the role of airborne transmission altered. Knowing the complex transmission mechanisms of respiratory transmission and the role of the airborne route in the transmission process is essential in determining the effectiveness of airborne control measures. Hence in this study we also tested the virus exposures dose to infectious patients at different distances when patients were carrying out different respiratory activities. A complex model considering transmission mechanisms of respiratory infections was also built to evaluate the influence of the transmission route in large scale outbreak simulations. The results showed that increasing ventilation rate especially in homes, offices and classrooms is an effective control method for controlling airborne and partially airborne transmitted infections. Combining isolation and increasing ventilation rate can reach similar or even better control effect compared with other general public health interventions such as vaccination. This finding suggested the important role of ventilation in airborne infectious disease prevention and intervention. The ventilation rate required by existing ventilation standards such as ASHRAE 62 might be too low for the purpose of controlling possible airborne outbreaks. / published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy

Background: End Stage Renal Disease (ESRD) is one of the commonest diseases in Hong Kong. Patient with ESRD needs to start dialysis for life maintenance. Peritoneal dialysis (PD) is the predominant dialysis modality for home dialysis patients. More than 80% of dialysis patients in Hong Kong receive PD. However, it also brings out some PD-related infectious complication such as tenckhoff exit-site infection, tenckhoff tunnel infection and PD peritonitis. These complications markedly contribute to treatment failure in PD patients. Especially PD peritonitis, it remains a leading complication of PD. Also it is a main cause of patients switch to haemodialysis (HD)and discontinue PD. Nevertheless, if the primary prevention of PD education do better, research evidences have shown that peritonitis infection rate of PD patients can be effectively reduced. It can be achieve by the utilization of effective education strategies and advanced training skills to enhance patients’ knowledge and skills of peritoneal dialysis. Purpose: This written proposal aims to identify the best evidence of PD education and to develop a guideline for this health education programme. The goal of the programme is to reduce the rate of PD-related infection for patients who started PD treatment at home after first CAPD training and education. Method: A total of 12 studies which focused on PD education and strategies for reducing PD-related infections were searched from electronic databases. Data extraction and critical appraisal were performed on these 12 studies. After the integrative review, the implementation potential was assessed. The results shown that the transferability of finding is high and it is feasible to conduct the proposed innovation. Then, the evidence-based guideline for PD education programme were developed and based on the high and medium level of evidence with grades of recommendation stated. Before implementing the proposed innovation, a communication plan was developed and targeted the various stakeholders (the administrators, nurses, patients and their relatives). The proposer would initiate the change and the programme leading group would guide and sustain the proposed innovation. The next process was planning a pilot study to examine the feasibility of the proposed innovation before implementation. Finally, different outcomes of the programme has been identified and evaluated in the evaluation plan. The methods for data analysis were formulated. Conclusion: The proposed peritoneal dialysis education programme with best evidences support is worthy to be adopted in the clinical setting for the beneficial of PD patients to reduce their PD-related infectious complications. / published_or_final_version / Nursing Studies / Master / Master of Nursing

PhD Faculty of Health Sciences, University of the Witwatersrand, 2009. / HIV/AIDS was discovered almost a quarter of a century ago and has so far claimed the lives of more than 25 million people worldwide. Developing countries remain disproportionately affected, with sub-Saharan Africa contributing more than two-thirds of infections globally. Sexual transmission is the primary route of HIV/AIDS acquisition, and women bear the greatest burden of this pandemic. We are now at a stage where biotechnological advances are needed that can either cure HIV/AIDS, stimulate the immune system to produce anti-HIV-antibodies by vaccination, or prevent HIV infections. One of these advances has been the development of various microbicides. However, a lack of effective drug delivery systems for these agents has remained as a rate-limiting step towards successful HIV prevention. In an attempt to overcome this problem, this study aimed at designing and developing a novel intravaginal bioadhesive polymeric device (IBPD) as a delivery system to effectively deliver a microbicide {polystyrene sulfonate (PSS)} and antiretroviral (ARV) {3'-azido-3'-deoxythymidine (AZT)} combination to the vagina. The development of a successful intravaginal microbicidal drug delivery system requires the design of a formulation to deliver the microbicide-ARV combination in a safe, effective, and consistent manner. The first step therefore was to undertake extensive preliminary screening studies on various polymeric materials using a one variable at a time (OVAT) approach to find suitable polymers for developing an IBPD. Initially 18 biodegradable and biocompatible polymers were employed to produce 62 formulations that were further screened through the OVAT approach to result in 15 lead formulations. Two major concerns of this study were the attainment of satisfactory residence time of the IBPD in the vagina as well as the ability of the IBPD to contain and release the microbicide-ARV in a controlled manner. Therefore, optimization of the IBPD was based on these two requirements for which proper matrix integrity was a pre-requisite. Artificial neural networks (ANNs), a computational technique that is able to simulate the neurological processing ability of the human brain through mathematical modeling, was employed for optimization. The ANN approach confirmed that 5 of the 18 studied polymers could be suitable for the development of an optimized IBPD. To finally attain good vaginal retention for the developed delivery system, extensive bioadhesivity testing was undertaken on the optimized device. Thorough in vitro and ex vivo bioadhesivity analysis was conducted using physicomechanics and computational structural modeling. Allyl penta erythritolcrosslinked poly acrylic acid (APE-PAA) appeared to contribute most to the bioadhesivity. Apart from being employed as a matrix component, PAA was further used as a coating agent to achieve extended bioadhesivity within the posterior fornix of the vagina. Since prolonged release and suitable permeation of the microbicide-ARV across the vaginal tissue was a critical requirement of this study, the device was designed to provide a controlled and prolonged drug release. Prolonged release for up to 72 days was achieved. Furthermore, the design was constructed to ensure that the released drug could permeate into the vaginal tissue and be retained substantially. This was determined by measuring drug flux through ex-vivo permeation studies using freshly excised pig vaginal tissue in a Franz Diffusion Cell (FDC) apparatus. The ultimate aim of the study was to have the IBPD well accommodated in the vagina for successful prevention of STIs and HIV infection. Achievement of this aim was ensured by undertaking extensive in vivo studies in Large White pig model. The IBPDs were inserted under anaesthesia into the posterior fornix of the vagina, using a novel applicator. To detect the retention of the IBPDs and determine their sequential biodegradation pattern in the vagina, X-ray imaging was employed, using radio-opaque Barium Sulphate (BaSO4). To demonstrate that the developed drug delivery system acted locally and was only minimally absorbed systemically, blood samples were taken from the jugular vein of each pig at pre-determined time intervals and subjected to UPLC analysis. The drug content in the vaginal tissue at the end of the study was also determined. Histopathological evaluation was carried out on vaginal epithelium to access the potential for toxicity of the IBPDs. The drug content analysis revealed that greater amounts of AZT and PSS were retained in the vaginal tissue with relatively small quantities (AZT:17%; PSS:13%) crossing into the systemic circulation. The results from the toxicity studies showed that the IBPDs were safe for use. This suggests that the developed drug delivery system (the IBPD) may be suitable for application in the prevention of STIs and HIV infections.

Hemodialysis patients are at high risk of acquiring a blood stream infection (BSI), the second leading cause of death in this population. The purpose of this project was to create a clinical practice guideline (CPG) based on current evidence-based practice (EBP) that would bring a cohesiveness to the policies and provide an auditing tool to monitor infection control practices. Current literature supports the bundle approach, a small set of EBPs combined as a group of recommended interventions that apply to a specific patient population with the goal of improved delivery of care. The hemodialysis bundle project incorporated the theory of planned behavior to create a set of evidence-based interventions developed from an in-depth review of current, peer-reviewed studies. Three experts reviewed the CPG using the Appraisal of Guidelines for Research and Evaluation Instrument II; the scores from the 6 domains showed approval of the guideline as it was created with a score of greater than 90%. The three experts were chosen because they are responsible for updating and writing policies for the hemodialysis units. The creation of a CPG to improve infection control practices might benefit hemodialysis staff by providing an organized and cohesive method of following current policies. The new CPG might impact social change by applying current EBP to a clinical practice with end results of improving hemodialysis care and patient outcomes.

published_or_final_version / Nursing Studies / Master / Master of Nursing

No description available.

Errata sheet has been pasted onto the front end-paper. / Bibliography: leaves 208-217. / x, 217 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Outlines a systematic synthesis and testing of continual sterilization design. Principal aim is to evaluate and develop mathematical models for sterilization, undertake experimental studies for determining thermal inactivation effects on continuous processing of a liquid containing contaminant bacteria and compare the data obtained with those predicted by a selected model. / Thesis (Ph.D.)--University of Adelaide, Dept. of Chemical Engineering, 2001?

Errata sheet has been pasted onto the front end-paper. Bibliography: leaves 208-217. Outlines a systematic synthesis and testing of continual sterilization design. Principal aim is to evaluate and develop mathematical models for sterilization, undertake experimental studies for determining thermal inactivation effects on continuous processing of a liquid containing contaminant bacteria and compare the data obtained with those predicted by a selected model.

Submitted in fulfillment of the requirements for the degree of Doctor of Technology: Health Sciences, Durban University of Technology, Durban, South Africa, 2018. / Soil-transmitted helminths are a major health concern, especially in tropical and sub-tropical regions. Poor sanitation and poverty are major pre-disposing factors contributing to increase in infections. Infection with STH is mainly through exposure to water, soil and food contaminated with the eggs of these parasites. Accurate detection and quantification of STH eggs in environmental samples is therefore critical for the determination of infection risks from exposure. Accurate detection of these eggs is also important in the adoption of risk reduction strategies. This thesis presents the development of a revised method for the accurate detection and quantification of STH eggs in different environmental matrices, such as wastewater, sludge etc. It further presents the application of this method in the comparative determination of STH egg reduction efficiencies of centralized wastewater treatment plants and decentralized wastewater treatment (DEWATS) plants in Durban, South Africa and Maseru, Lesotho. The concentration of viable STH eggs in dried sludge from Durban, South Africa and Dakar, Senegal was also determined and compared with both WHO guidelines and South African national standards for sludge reuse. The risks of infection with STHs for different populations exposed (directly and indirectly) to wastewater, wastewater contaminated surface water and sludge were determined using both quantitative microbial risks assessment and epidemiological approaches. Despite the plethora of methods available for the detection and quantification of STH eggs in the environment there is no internationally accepted method, however the most commonly used methods are based on the principles of sedimentation, differential flotation and microscopy. These are mainly adaptations of the WHO and USEPA methods. These methods were found to be similar with a few differences which affected the recovery rates reported. However, the major challenges with the conventional methods are the time needed for sample analysis and the use of reagents that could possibly affect the recovery of viable STH eggs. A new revised method was developed based on review of literature and laboratory experiments. In this method the heterogeneity of environmental samples was accounted for by the development of different pre-processing steps, involving the use of detergents to aid in the separation of eggs from particles in samples such as sludge, UD waste and untreated wastewater. Additionally, the use of sieves of different pore sizes ensured that the number of debris on the microscope slides was reduced considerably. The use of these sieves also reduced the time need for sample analysis, due to the elimination of the spontaneous sedimentation step, which is commonly used. This spontaneous sedimentation step takes between 12-24 hours therefore prolonging the time needed for sample analysis. Reagents such as acetoacetic acid and ethyl acetate were found to result in considerable loss of egg viability after just 5 minutes of exposure. This new method therefore does not involve their usage. The elimination of the use of acetoacetic acid and ethyl acetate step also reduces the number of steps involved in sample analysis. This reduces room for error as well as helping in fast analysis of samples. In addition to a much faster sample analysis the method has recovery percentages of 80.25% to 97.63% in sludge and wastewater samples respectively, with sensitivity of 2-3 eggs per liter in wastewater samples and 5-7 eggs per 20 gram of sludge. Exposure to STH eggs in the environment is mainly through wastewater, either treated or untreated, this exposure could therefore be eliminated through wastewater treatment. Centralized wastewater treatment systems are the most favored treatment options globally. These centralized treatment systems incur high cost of construction, maintenance and operations which may hamper the robustness in developing countries and rural areas. One of the most widely used alternative means of wastewater treatment is the anaerobic baffled reactors (ABRs) and planted gravel filters (PGFs) (collectively referred to as DEWATS in this thesis), which have been considered as low cost, effective wastewater treatment options. However, there is lack of comparative assessment of the STH egg removal efficiency of these two different wastewater treatment approaches. Eggs of Ascaris spp, hookworm, Trichuris spp, Taenia spp and Toxocara spp were the commonly recorded STH eggs in the untreated wastewater at the inlets of the centralized wastewater treatment plants as well as the DEWATS plants (except for Toxocara spp). There was variation in STH egg concentrations between and within the study areas, indicating difference in STH infections among the populations both in Durban and Maseru. STH egg removal varied between and within the different wastewater treatment plants as well. The DEWATS plants achieved 95-100% STH egg removals as compared to the 67 to 100% in the centralized wastewater treatment plants. This could be attributed to the difference in treatment processes. Among the different STHs, reduction in Ascaris spp eggs was significantly higher, irrespective of the type of treatment, which is attributed to the high relative density of the egg resulting in a higher settling velocity than the other STH eggs. Reduction or elimination of STH eggs through wastewater treatment is achieved by removing the eggs from the wastewater into the sludge. STH egg concentration in sludge is therefore mostly higher than in the wastewater. Sludge from Durban and Dakar after 60 days of drying under ambient environmental conditions contained very high concentration of viable STH eggs. Ascaris spp, hookworm, Trichuris spp, Taenia spp and Toxocara spp were the commonly recorded STH eggs, except for Dakar were Taenia spp and Toxocara spp were not detected in the sludge. STH egg concentrations were higher in Dakar than in Durban, with viable STH egg concentrations exceeding both the USEPA regulatory value (≤0.25 eggs/g TS) and the WHO guideline value (≤1 eggs/g TS). This variation in egg concentration could be attributed to the difference in prevalence and intensity of STH infections in the two study areas. Over a ten-month study period concentration of viable eggs in the sludge from Durban varied considerably, probably influenced by the environmental conditions. A decay rate of 0.0056 per day was calculated for egg die-off during drying. The rate of decay is low therefore drying alone cannot produce sludge meeting both local and international standards and guidelines for sludge reuse. Determination of STH infection risks due to exposure to wastewater and sludge either directly or indirectly is critical in the prevention of infection. Exposure to the effluents during wastewater irrigation is one major route of infection. STH egg concentrations in the final effluents from the centralized and DEWATS wastewater treatment plants were consistently higher than the WHO recommended guideline for unrestricted agricultural use (≤ 1 helminth egg/L), whereby the direct reuse of the effluents for agriculture was found to pose a higher risk than the WHO tolerable risk of infection (1 ×10-2 pppy) for farmers and consumers. Annually the use of effluents from the DEWATS plants poses the least risk of infection (1.9 ×10-2 (±2.4×10-4)), which is marginally higher than the WHO tolerable risk value. Well maintained DEWATS plants are more efficient in removing or reducing the concentration of STH eggs in wastewater and therefore pose the least risks of infection compared to centralized wastewater treatment plants. Consumers of vegetables from these farms are also at considerable risks of STH infections. Probabilistic assessment of the STH infection risks showed that farmers applying sludge from Durban and Dakar without adequate protective measures had risks of infections higher than the WHO tolerable risks figure (1×10-2 pppy). Based on the estimated risks of infection after decay, exposure to farm soil after 40-50 days of sludge application may reduce the risks of infection to levels lower the WHO tolerable risks value. However, this may not be practical due to the need for farmers to attend to their crops frequently. Incorporation of the decay of the eggs into the risks assessment also indicated that, using lettuce as a representative vegetable, harvesting of vegetables in Dakar could be done after 40 days of sludge application to reduce the risks of infection to the WHO tolerable value but in Durban harvesting after 30 days ensures that consumers are protected. Therefore, to protect both the farmers and consumers exposed to STH eggs through wastewater/sludge reuse in agriculture the implementation of the WHO multi-barrier approach to risk reduction is required. Risks of STH infections could be directly estimated using epidemiological approaches. By using this approach, the concept of STH infection risks for farmers using wastewater was assessed through direct measurements of the concentration of STHs both in wastewater used for irrigation and the farm soil, as well as the actual load of STHs ova in the stool of farmers and their family members. In Kumasi, Ghana, wastewater used for irrigation of vegetables and the farm soil contained high concentration of STH eggs. There was positive correlation between STH concentrations in the wastewater/soil and STH eggs load in stool of the exposed farmers. Stool analysis after 3 months, following deworming, showed a fast re-infection rate. Farmers exposed to the wastewater were three times more likely as compared to the control group of non-farmers to be infected with Ascaris spp (OR = 3.9, 95% CI, 1.15-13.86) and hookworm (OR = 3.07, 95% CI, 0.87-10.82). These risks of infection were higher in the rainy season than the dry season. This corresponds to a higher egg concentration in wastewater used for irrigation during this period. This indicates a relationship between STH infection and egg concertation in the environment. This study therefore contributes to the evidence-based conclusion that wastewater irrigation contributes to a higher incidence of STHs infection for farmers. In conclusion, this thesis therefore presents a new revised method that can be used to determine the STH egg concentration in different environmental samples. The development of this method also provides an opportunity to comparatively assess the STH egg reduction/removal efficiency of the more commonly used centralized wastewater treatment plants and DEWATS plants. The accurate quantification of viable STH eggs provide inputs for the probabilistic assessment of STH infection risks for different populations exposed to effluents from these two wastewater treatment approaches. This assessment of risks provides a public health perspective to the wastewater treatment. Additionally, it was concluded with the used of this method that drying of sludge for 60 days in Durban or Dakar does not produce sludge of good quality for agricultural application. This was confirmed by the estimates of STH infection risks determined using quantitative microbial risks assessment. This thesis therefore shows the importance of accurate quantification of STH eggs in the determination of infection risks either though QMRA or epidemiological approache / D

Introduction. Infection prevention and control is both a national and international priority, with compliance with precautions being sub-optimal. One of the reasons suggested for poor compliance is a lack of appropriate education for health care professionals. There is a limited body of research available which considers infection prevention and control education for nursing students, particularly in clinical placements and no identified research in this area in midwifery. Aim. A body of research was undertaken with the overall aim of exploring and analysing the experiences and learning needs of nursing and midwifery students in relation to infection prevention and control in their clinical placements. Methods. An interpretivist approach was utilised to undertake semi-structured interviews with 32 nursing students, 15 midwifery students and 31 nurse mentors within a body of research comprising of three related studies. Date were analysed using Framework Analysis. Results. Several themes emerged from the body of work including the nature of infection prevention and control practice that is perceived as good or poor practice; attitudes towards infection prevention and control; barriers and motivators to learning about infection prevention and control; attitudes towards the infection prevention and control nurse and barriers to reporting poor practice. Conclusions. The body of work presented has several implications for future practice and research. New knowledge has been developed in particular in relation to perceptions of the role of the infection prevention and control nurse, barriers to reporting poor practice, the infection prevention and control education of midwifery students and the acceptance of poor practice as the norm. By triangulating findings from three separate but related studies, the research has been strengthened, providing additional support for the conclusions reached.