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The purpose of the study was to perform a quantitative occupational stress risk assessment (OSRA) to evaluate the impact of health promotion (HP) lifestyle and perceived nature contact on the consequences of perceived stress from exposure to nursing stress risk factors. Perceived stress is defined as the employee’s personal interpretation of his or her work circumstance and any discrepancy between workplace demands (stressors) and individual capacities (resources). Registered nurses (RNs) in patient care settings are prone to high levels of perceived stress, which can cause errors in clinical care giving. High perceived stress is a consequence of risk factors from a nurse’s daily work routine including: workload, death and dying, inadequate preparation for role, staff support, uncertainty concerning treatment, communication with physicians, and communication with other nurses. Mitigating perceived stress improves nursing job performance, job satisfaction, and overall employee health, while reducing mental fatigue, absenteeism, and burnout. Methods performed included: Aim 1) a systematic literature and meta-analysis to establish benchmarks for perceived stress in nursing professionals for comparison of United States (US) and International healthcare settings; Aim 2) a cross-sectional study using a 125-item survey instrument administered online to an RN study population to evaluate relationships between perceived stress, HP lifestyle, and perceived nature contact; and Aim 3) a quantitative OSRA to rank nursing stress risk factors and examine differences by gender, ethnicity, and race. Results were: Aim 1) Perceived Stress Scale 14-item (PSS14) value for International nursing studies was 25.41 (95% CI 21.1 to 29.7), while US PSS14 nursing studies yielded a value of 23.8 (95% CI 19.8 to 27.7). Aim 2) the present study found Southern California RNs (n=161) had the same perceived stress (m = 22.8, 7.06 SD, p=0.082) as other US nursing professionals. RN perceived stress sc

Surrogate organisms have been used to study highly pathogenic organisms, or organisms that cannot be cultured in the laboratory. Surrogates are selected based on multiple similarities to the pathogen, such as morphology, genome size and structure, and environmental characteristics. This dissertation utilized MS2 coliphage as a surrogate for norovirus and Ebola virus in three environments. MS2 is an icosahedral, single-stranded RNA bacteriophage. It is a male-specific coliphage that infects the bacteria Escherichia coli. Its properties, such as morphology and survival in the environment, have been likened to those of many enteric viruses. Because of this, it has been used as a surrogate for pathogenic enteric viruses for disinfection testing on surfaces, in water and in food; modeling the movement and survival of pathogens in different environments; and transfer properties from surfaces. This dissertation utilized MS2 as a surrogate in three different studies. In the first, MS2 is used as a surrogate for human enteric viruses in irrigation canals to predict the re-suspension of pathogenic viruses from bed sediment into overlying irrigation water using a flume to re-create field conditions in the laboratory. MS2 re-suspension into the overlying water was characterized at varying flow rates and velocities using two sediment types. Its overall re-suspension was not statistically significantly different (p > 0.05) between flow rates. The additional studies in this dissertation used MS2 as a surrogate for Ebola virus in human waste. Ebola virus is a BSL-4 organism that is spread through direct contact with bodily fluids. It is found in bodily fluids in concentrations between 10^5.5 and 10⁸ genome copies per milliliter. In the first study using MS2 as a surrogate for Ebola virus, efficacies of four disinfectants were tested using 10¹² PFU of MS2 in one liter containing 2.25% (w/v) organic matter at three contact times (1, 15 and 30 minutes). The purpose of this study was t

Protozoa and bacteria can easily cause disease in humans, specifically E. coli, Plasmodium falciparum, and Cryptosporidium parvum. These three pathogens are associated with large public health concerns that span the globe. The variety of locations in which these can be found is extremely high. Cryptosporidium spp. are extremely resilient when in oocyst form, P. falciparum is in the Anopheles spp. mosquito, while E. coli can be found on anything from food and water, to the skin and gut. The diverse range of locations these can be found in means that a portable sensor for their detection is necessary. In detecting Cryptosporidium, microscopy is the preferred method of identification currently. This requires a trained lab technician as well as calibrated and expensive optical equipment. Technician error can lead to false negative or positive diagnoses as well as sample destruction. A method to remove this technician interaction is thus necessary. This method must allow for objective results that are not open to interpretation. Particle immunoagglutination assays with Mie scatter allow for such an approach using inexpensive components. Particle immunoagglutination relies on the principles of antibody-antigen interaction and antibody conjugated latex particles. Using highly carboxylated latex particles, it is possible to attach IgG antibodies that are specific to a target antigen. Mie scatter is governed by particle size rather than wavelength as other forms of scatter. These two combined allow for an increase in light scatter based on particle size. This is correlated in a linear manner as long as the number of antibody-conjugated particles is higher than the number of antigens. Microfluidics is an ever growing field in the field of lab-on-a-chip that works very well with particle immunoagglutination. In this paper, a method to rapidly identify the presence of Cryptosporidium using microfluidics and particle immunoagglutination is discussed and analyzed. This method all

Previous studies have shown that low-income Latinos frequently drink bottled water instead of tap water and might be at increased risk for dental caries from unfluoridated bottled water. The goals of this study were to: 1) determine if a difference exists between grab samples of municipal tap water and bottled water used by families in Nogales, Arizona in chemical and microbial contaminants; 2) understand the risk perceptions these low-income families have about both their publically supplied tap water, bottled/vended water; and 3) examine whether families have adequate fluoride levels in their drinking water for optimal dental health. Tap and bottled water samples were collected from thirty of these households for analysis of drinking-water contaminants regulated by the U.S. Environmental Protection Agency (USEPA). Bottled water included small (0.5 L) and large (3.8 L), individually sealed water bottles as well as water vended into reusable containers from self-service vending machines or from water stores. Some of the large bottles were purchased sealed, but had been previously opened and partially consumed by study participants. In addition to the 30 households mentioned above, an additional sixty low-income Latino households, who primarily drink bottled water, were also recruited for this study to complete a questionnaire on risk perceptions related to drinking water consumption, water storage practices, and fluoride supplementation. There were no significant differences in the concentration of chemical contaminants between tap, bottled and vended water, and none of the chemical concentrations exceeded USEPA regulations. Escherichia coli (E. coli) was confirmed in 3% (1/30) of tap, 0% (0/8) of sealed bottled, 40% (2/5) of previously opened bottled, and 35% (6/17) of vended water samples. One of the 3 samples collected directly from a vending machine had an E. coli concentration of 0.33 CFU/100 mL. None of the 10 samples collected directly from sealed bottles pur

Heavy metals have been known to possess antimicrobial properties against bacterial, fungal, and viral pathogens. Silver and copper in particular have been used for millennia to control bacterial and fungal contamination. Metal nanoparticles (aggregations of metal atoms 1-200 nm in size) have recently become the subject of intensive study for their increased antimicrobial properties due to their increased surface area and localized release of metal ions when attached to pathogens. In the current studies, metal and metalhalide nanoparticles including silver (Ag), silver bromide (AgBr), silver iodide (AgI), and copper iodide (CuI) nanoparticles were evaluated for their antibacterial efficacy against two common bacterial pathogens. All of the nanoparticles significantly reduced bacterial numbers within 24 hours of exposure and were more effective against the Gram-negative Pseudomonas aeruginosa than the Gram-positive Staphylococcus aureus. CuI nanoparticles were found to be highly effective, reducing both organisms by >4.43 log₁₀ within 15 minutes at 60 ppm Cu. CuI nanoparticles were selected for further evaluation against a range of microorganisms to determine their broad spectrum efficacy. CuI nanoparticles formulated with different stabilizers (sodium dodecyl sulfate, SDS; PVP) were tested against representative Gram-positive and Gram-negative bacteria, Mycobacteria, a fungus (Candida albicans), and a non-enveloped virus (poliovirus). Both nanoparticles caused significant reductions in most of the Gram-negative bacteria within five minutes of exposure (>5.09-log₁₀). The Gram-positive bacterial species were more sensitive to the CuI-SDS than the CuI-PVP nanoparticles. Likewise, C. albicans was also more sensitive to the CuI-SDS than the CuI-PVP nanoparticles. In contrast, the acid-fast Mycobacterium smegmatis was more resistant to the CuI-SDS than the CuI-PVP nanoparticle solutions (2.54-log₁₀ vs. 3.80-log₁₀ after 30 minutes). Poliovirus was more resistant than the ot

Microbes survive for an extended period of time on fomites. With new strains of pathogens constantly emerging, it is important to understand their survival and spread and to evaluate the efficiency of new disinfection methods. The purpose of this study was to determine the occurrence of pathogens on fomites, and evaluate different disinfection methods (household bleach and steam vapor). Fomites were sampled in a variety of environments for the presence of pathogens including methicillin intermediate- and resistant- Staphylococcus aureus, Clostridium difficile, Penecillium brevi-compactum, Alternaria alternata and novel H1N1 influenza A. Samples were assayed using both cultural and genetic techniques to determine the microbial occurrence. In disinfection studies, samples were collected before and after disinfectant application. Steam vapor was effective at reducing microbial occurrence by>90% with a minimal contact time of 10-20 seconds on hospital fomites. The material and shape of the surface had an effect on the reduction rate, due to access of the disinfecting agent. In addition, low levels of initial contamination limited the reduction rate. Many surfaces had a starting contamination level of less than 3 log10 and after disinfection the contamination levels, in 69% of the samples, were at or near the limit of detection. This suggests a higher reduction is feasible. Household bleach reduced the presence of mold spores and mycelium by >99% on gypsum-wall board. Reduction rates were influenced by the growth stage of mold, with the mycelium requiring additional disinfectant application to achieve the 99% reduction rate. Novel H1N1 influenza A was not recovered on any surfaces in day care facilities and elementary schools. This is consistent with previous studies looking at H1N1 influenza occurrence in similar environments, though it is different from H3N2 influenza A studies. Survival differences among varying influenza strains are expected to have an impact on path

Enteric pathogens in pool water can be unintentionally ingested during swimming, increasing the risk of Acute Gastrointestinal Illness. Swimmer activities and behaviors influence pool water ingestion rates, and can be quantified for use in risk assessment. Enteric infection risk estimates help identify data gaps, areas to focus resources, and research needs. Primary objectives of this study were to develop electronic, self-administered "exposure" and "pool operations" questionnaires; to gather swimmer behavior and activity data for use in risk assessment; and to estimate Cryptosporidium parvum infection risk in swimmers. Results were used to identify data gaps and future research needs relative to treated recreational water. To achieve these objectives, 126 swimmers were recruited at four pool sites in Tucson, Arizona, video-taped, and asked to complete a post-swim questionnaire. Forty-six of the 126 swimmers submitted a 24 hr post-swim urine sample for quantifying pool water ingestion. Head submersion frequency and duration and splashes to the face were observed and quantified in video analysis, and activities and behaviors were reported on the exposure questionnaire. Variable data were analyzed for associations with pool water ingestion estimated by urinalysis. Results indicate questionnaires can be self-administered electronically; the exposure questionnaire can be used to estimate ingestion magnitude in place of urinalysis; leisure swimming activities (diving, playing, splashing, wading, sitting) and frequency of face splashes are ingestion exposure factors; and that Cryptosporidium infection risk is greatest among leisure swimmers. Other activities observed and suspected of having associations with ingestion were short submersion durations (<1 sec), and spitting and spouting water. More research and resources focused on improving treated recreational water environments and reducing risks among swimmers are needed. Developing an indicator organism test represent

Case-control studies are the traditional ways in which foodborne enteric diseases are studied and outbreaks are investigated. This method has some significant limitations and biases for diseases with low efficiency reporting rates, such as Campylobacter, a common foodborne disease. Case-case methodologies have been explored for these studies but have been implemented without any clear strategy. This dissertation aims to first, determine the common risk factors for Campylobacter in Arizona using the traditional case-control study design, second, to systematically compare case-case studies to the more common case-control studies, and third, to simultaneously compare the results of a community outbreak of Campylobacter using both case-control and case-case study designs. Results from these studies identified some unique risk factors for routine Campylobacter infection in Arizona that will be used to enhance surveillance for the disease in the state. A systematic review of case-case studies used for enteric diseases found that there are specific recommendations that can be put into place in determining what comparison cases should be selected based on the primary aims and goals of the study. Finally, the results of the simultaneous case-case and case-control studies of a Campylobacter outbreak showed that these methods may work best in conjunction with one another and in doing so, the most accurate depiction of the source of infection can be determined.

It is now widely accepted that surface contamination plays an important role in the transmission of both respiratory and gastrointestinal infections in the domestic environment and community setting. The efficiency of transfer of a pathogen to the hand from a fomite is important in modeling transmission in microbial risk assessment models. The objective of this study was to use published literature to assess the role of fomites and hands in disease transmission, and to conduct fomite-to-finger transfer studies from various porous and nonporous fomites under different relative humidity condition using non-pathogenic strains of Escherichia coli, Staphylococcus aureus, MS2 coliphage, Bacillus thuringiensis spores, and poliovirus 1; to evaluate the persistence of bacteria and viruses on surfaces; to examine bacteria and virus transfer from treated surfaces; and to conduct a foodborne quantitative microbial risk assessment using Campylobacter jejuni from the data obtained in these studies. It was found that numerous factors influence the transfer efficiency of microorganisms, with moisture being the most important, with greater transfer under humid conditions. Other factors influencing transfer include drying time, contact time, pressure, friction, type of material, and porosity of the fomite. Percent transfer was greater under high relative humidity for both porous and nonporous surfaces. Most organisms on average had greater transfer under high relative humidity (40 - 65%) compared to low relative humidity (15 - 32%). Relative humidity and fomite type influenced the survival of all studied organisms; survival was greater on nonporous surfaces than those for porous surfaces. Test organisms were reduced up to 99.997% on the fomites after the surfaces were wiped with a disinfectant wipe. Microbial fomite-to-finger transfer from disinfectant wipe-treated surfaces were, lower than from non-treated surfaces. The disinfectant-wipe intervention reduced the risk of Campylobacte