No description available.

A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Public Health. Johannesburg, April 2012 / Introduction: Sub-Saharan Africa has a high burden of HIV and other blood borne pathogens. Botswana’s estimated prevalence of HIV and HBV are between 17-40%, and 14 % respectively. Ninety percent of the three million health care workers exposed annually to blood borne pathogens through injury are in developing countries. Previous studies in Botswana indicate 24%-26% health workers sustain needle stick and other sharps injuries annually, posing a threat to them. Dentistry requires work with sharp objects in a confined space; thus oral health workers (OHWs) are at high risk of infection from occupational blood exposures (OBEs). Universal (Standard) Precautions were first recommended by the Center for Disease Control in the United States of America and were adopted in several countries, including Botswana, to minimize the risk of exposure to, and infection from, blood. However, studies in different health care settings, mainly in developed countries, have shown that these guidelines are not always adhered to. Few studies have been done to evaluate their utilization in developing countries. Aim: To quantify the occupational blood exposure experience of OHWs in Botswana’s public service and determine the infection control practices through self reporting and observation. The Objectives were: 1) To determine the demographic profile of the OHWs in Botswana, 2) To determine self reported blood exposure experience of oral health workers within the 12 months prior to the study, 3) To determine self reported infection control practice of oral health workers within the 12 months prior to the study, 4) To determine the knowledge of risks associated with blood borne pathogens amongst oral health workers at the time of the study, 5) To determine, by observation, which v precautions were practiced by oral health workers to prevent exposure at the time of the study, 6) To assess whether there was a written policy available in the dental facility on the prevention and management of occupational blood exposures. Methodology: A cross sectional descriptive survey was carried out using a combination of self reporting and observation. A total of 85 OHWs in 5 of the 6 main oral health facilities were invited to participate. Knowledge of risks pertaining to blood borne pathogens, frequency of blood exposures and practice of universal precautions were assessed. Documents and posters were also reviewed. Results: Sixty eight (80%) OHWs returned the questionnaires and 51 (60%) observations were carried out. At least 80% of respondents had correct knowledge of occurrences that can contribute to the spread of blood borne pathogens in the dental environment. Over 60% were aware of universal precautions and 75% knew that post exposure prophylaxis (PEP) was available at their facilities. Almost 43% of the respondents had experienced blood splashes in the last year and 35.3% experienced needlestick injuries. Half of these reported the injury and 16.2% took PEP. Predictors of needlestick injuries during the previous year were perception of risk, knowledge of and compliance with, Universal Precautions Personal protective equipment was poorly utilised; only 17.6% were observed to use protective eye wear. Two thirds of the respondents were observed to use double-handed recapping. None of the facilities visited had a written protocol displayed. Conclusion and recommendations: The prevalence and reporting of OBEs amongst vi OHWs were comparable with findings of other studies. Self protection through compliance with universal precautions, immunization and post exposure prophylaxis was not fully utilised. The high burden of disease in the country warrants that further efforts be made to protect oral health workers. Appropriate guidelines should be made available at all dental facilities and staff needs to be retrained regarding standard precautions. Monitoring of exposures and vaccination status should be carried out. Further research should be undertaken regarding the poor uptake of prophylaxis.

No description available.

Faculty of Health Sciences, Master of Science in Medicine in the field of Epidemiology and Biostatistics, 9502650w / An autopsy-based case-series of South African miners was used to evaluate the evidence required to attribute a miner’s lung cancer to occupational asbestos exposure for compensation. The slightly different Helsinki (1997) and National Institute for Occupational Health (NIOH) criteria (1988) require that one of four factors (asbestosis, occupational exposure, raised burden of asbestos fibres and/or bodies) be fulfilled for attribution. These criteria were applied to the case-series to determine and compare the proportions of NIOH- and Helsinki-attributable lung cancers. Of 195 lung cancer cases, 47% (91) were Helsinki-attributable and 52% (101) NIOH-attributable: with 72% concordance. Some differences in the details of occupational exposure criteria and methods for assessing the burden of asbestos in the lung were responsible for differences in these proportions. If attribution had taken place using only presence of asbestosis and the occupational exposure history, many cases would not have been attributable to asbestos. Therefore, taking into account burden of asbestos in lung tissue was important. However, it was found that phase contrast microscopy (PCM) for counting asbestos bodies was “sufficient” and that scanning electron microscopy (SEM), advocated by the Helsinki criteria, added <1% of the cases, suggesting that the cost of expensive SEM fibre counts in a developing country may outweigh the benefits. Using the Helsinki criteria as the gold standard, the sensitivity of the NIOH criteria was 75.8% (95% CI: 65.7 – 84.2).

This thesis addresses the much needed quantitative assessment of the physiological effects the magnetic fields used in MRI. MRI has a well-earned reputation for being a safe, non-ionising alternative imaging modality for both the patient and MR practioner alike. Although the operating environment can prove hazardous for inexperienced and untrained personnel, appropriate training and adoption of safe working practices can prevent adverse incidents.

Chlorpyrifos, an organophosphate pesticide moderately toxic to humans via inhalation and dermal absorption (LD50 oral, rat = 226 mg kg-1, LD50 skin, rabbits = 1265 mg kg-1), is widely used to eradicate termites in Australia. A series of 28 surveys totaling 32 separate assessments, or 10% of all professional users in Perth, Western Australia, comprised biological monitoring, exposure assessment techniques, a health symptoms and work practices questionnaire. Chlorpyrifos metabolite 3,5,6-trichloro-2-pyridinol and alkyl phosphates were extracted from urine, and serum cholinesterase (SChE) and erythrocyte acetylcholinesterase from blood. Chlorpyrifos was extracted from 24 patches removed from a supplied cotton overall, cotton gloves worn under protective gloves, 7 absorbent patches placed on the skin and an organic vapour collection tube. Surface wipes were collected in the workers vehicle and on the workers forehead. Chlorpyrifos was applied in either 0.5% (n=2) or 1% (n=26) concentration of active ingredient in water solution. Surveys took place at pre-construction sites (n=5) where pesticide was sprayed onto a prepared site, existing buildings with concrete foundations (n=17) where pesticide was injected under pressure around the perimeter of the building and existing buildings with suspended floors requiring the worker to spray under floor (n=6). Combined left and right glove deposition was 9 mg hour- 1 (SD = 18 mg.hour-1). Mean deposition on overalls was 14 mg.hour-1 (SD = 12 mg.hour-1), on skin patches was 0.2 ƒÝg.cm-1.hour-1, on vehicle gear-stick was 3 ƒÝg (SD = 8 ƒÝg) and, on steering wheels¡¦ was 3 ƒÝg (SD = 3 ƒÝg). The mean protection 4 factor of overalls, a ratio of outer layer and inner levels, was 75 (SD = 411). Mean air concentration of chlorpyrifos during an application was 30 ƒÝg m-3, and 17 ƒÝg m-3 8 hour TWA (SD = 40 ƒÝg m-3 8 hour TWA), and in one group of 17 workers correlated (p<0.05) with ambient air temperature (15 to 38 oC). Urinary metabolites and SChE activity were effective indicators of exposure. The health symptoms questionnaire did not highlight significant health effects. A discrepancy between operators¡¦ perception of risk and their actual exposure requires addressing, for example the measured high deposition rate to hands was ineffectively controlled, as 48% or workers wore inappropriate or no gloves and only 26% washed their hands after completing their tasks. All workers indicated in the questionnaire they would wash their hands after completing their tasks. The questionnaire also highlighted a high incidence of poor work practices, 58% spilt the concentrate at least once a week, 74% had recently spilt/splashed diluted chlorpyrifos in their eyes and 90% on their boots, and 52% believed they would benefit from more education concerning chlorpyrifos. Observations concluded that workers unnecessarily increased their exposure by poor work practice. Recommendations include modification to pesticide worker education, licencing and health surveillance systems; an improvement in the understanding of the benefits of a health and safety management systems for employers, and pesticide suppliers taking a stewardship role in the usage of their products.

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 88-98).

Thesis (M.S.P.H.)--University of Michigan, 1932.

Thesis (Ph. D.)--University of Washington, 1991. / Vita. Includes bibliographical references (leaves [165]-177).

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [269]-277).