Karen Hastings Bartlett
Relevant Degree Programs
Great Supervisor Week Mentions
I am grateful for my PhD supervisor, Professor Karen Hastings Bartlett. She is compassionate and kind yet tough when needed without being overbearing. She is approachable and has created an environment conducive for trust and growth! She really cares for students! #Greatsupervisor #UBC
Graduate Student Supervision
Doctoral Student Supervision (Jan 2008 - Nov 2020)
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No abstract available.
Zoonoses (i.e., diseases transmitted from wild and domestic animals to humans) are health challenges with environmental and social determinants. For my thesis, I examined the environmental and social determinants of zoonoses transmitted by ticks, an obligate arthropod ecto-parasite, in the South Okanagan—a region with a potentially increasing risk of infection to tick-borne zoonoses. I first reviewed proximate (e.g., pathogens) and distal (e.g., land use) determinants of tick-borne zoonoses, and the management options to address them. This resulted in the description of an interdisciplinary approach to manage and prevent the diseases. In the remaining of my thesis, I contributed to this approach by examining two environmental determinants (prevalence of tick-borne zoonoses; and ecological dynamics of ticks and host species diversity) and two social determinants (impacts of land use practices on tick densities; and reasons for the adoption of protective practices). For the environmental determinants, the prevalence of tick-borne zoonoses was found to be low in the South Okanagan. As well, in contrast to previous works, host species diversity only reduced tick densities when there were specific changes in host species composition that affected tick-host dynamics. For the social determinants, tick densities were found to be better predicted by the type of land use practice, rather than the patch size of suitable habitat. Finally, adoption of protective practices was not related to knowledge of ticks and tick-borne diseases, but to the level of experience with ticks. These results help determine the prevalence of tick-borne zoonoses, and thus the infection risk of those diseases in the South Okanagan. They also help predict how various human activities at small ecological and large landscape scales may increase or decrease tick densities, and thus human exposure to ticks and their diseases. As well, these results can be used to develop risk communication strategies encouraging the adoption of protective practices, and reduce social concern regarding tick-borne zoonoses. Given that the prevalence of tick-borne zoonoses in the South Okanagan is low, adopting management options against ticks or tick-borne zoonoses may not be necessary. Instead, promoting personal protective practices against ticks may be cost-effective in reducing the infection risk of tick-borne zoonoses.
No abstract available.
Master's Student Supervision (2010 - 2018)
Interior living walls are promoted partly due to their ability to improve indoor air quality, and possibly reduce energy consumption related to ventilation. However, the studies done to demonstrate this ability are largely conducted in conditions that differs from those of building environments, and they have only focused on a single factor that impacts indoor air quality. This study examined several factors that living walls can affect indoor air quality (volatile organic compounds, carbon dioxide, relative humidity, and bioaerosols) and evaluated how each of these may improve or reduce indoor air quality.A test chamber was designed to simulate building environment conditions, including temperature, lighting, and ventilation. Three volatile organic compounds and CO₂ were added into the test chamber to simulate occupancy. Samples were taken in the test chamber with and without a living wall to determine differences due to the presence of a living wall.The interior living wall removed CO₂ and one of the three volatile organic compounds in the test chamber, increased relative humidity, and promoted the increased presence of bioaerosols. While living walls may improve some aspect of indoor air quality, considerations must be taken to mitigate the other impacts on indoor air quality.
Introduction:Healthcare-associated infections are a significant public health burden, which affect thousands of Canadians and cost millions of dollars, annually. Flushing toilets can generate pathogen-containing droplets and aerosols, and are a unique challenge in controlling pathogen transmission in healthcare facilities and other settings. This research assessed microbial dissemination of a) bacteria and b) virus from a flushing toilet in a patient area at Vancouver General Hospital. This project also c) evaluated the effectiveness of a permanently installed, automated ultraviolet C (UVC) device for reducing bacterial concentrations in air and on two surfaces in a shared patient bathroom at Lions Gate Hospital.Methods:a) Gram negative Escherichia coli and Gram positive Enterococcus faecalis, were used to simulate human stool during flushing events and viable air samples were collected with the Duo Surface Air System 360 sampler at multiple locations and time points post-flushing. b) A norovirus surrogate, MS2 bacteriophage, was also used to assess potential aerosolization of norovirus during flushing. c) Airborne and surface bacterial concentrations were compared in a bathroom with UVC and a comparable control bathroom.Results:a) Gram negative E. coli concentrations exceeded E. faecalis immediately post-flush at the location closest to the source, but decreased rapidly at successive time points and further sampling locations. In contrast, the Gram positive E. faecalis persisted significantly longer, and sampling location had no effect on its concentrations.b) Airborne phage was detected at concentrations far above the infectious dose for norovirus of 18 virions, and infectious phage particles were still present up to 60-minutes post-flushing.c) Airborne and surface bacterial concentrations were significantly reduced in the bathroom with UVC, compared to a comparable control bathroom.Conclusion:This work was the first study to evaluate both a Gram negative and Gram positive organism in the toilet plume, and show significantly longer persistence of the Gram positive bacteria. This research also showed that flushing toilets may generate airborne norovirus at concentrations capable of causing infection. Lastly, this work showed that optimized UVC is an effective adjunct to manual cleaning and infection control efforts in bathrooms.
For the purposes of this study, a community garden was defined as an urban space that is divided into plots and assigned to individuals or households, who share in communal responsibilities and decision-making.A literature review found that little research exists regarding community gardening, particularly in relation to policy but also to some aspects of health. There were also similarities in the research between community gardening, gardening in general, and social and therapeutic horticulture (STH). The aims of this study were to explore the motivations, experiences and practices of community gardeners and garden coordinators within the City of Vancouver, and become familiar with key characteristics of community gardens; to investigate any health effects perceived in relation to community gardening; and to examine the role of policy in shaping community gardening in Metro Vancouver and other municipalities.Using a listing of community gardens provided by the City of Vancouver, garden coordinators were contacted and requested to participate in the study by completing a brief survey on phone or electronically, and by forwarding a request for participation to their gardeners. Besides email, gardeners were also recruited at garden events, and were thereafter interviewed on phone for approximately an hour. For emotional and social well-being, as well as nutrition, community gardening was perceived to be highly beneficial. For mental abilities, physical fitness and financial status it was found to have little to no substantial benefit or harm, given that, for the latter two, most community gardeners were regularly involved in more rigorous physical activity, and were also socioeconomically secure. Most gardeners were also less than 50 years of age, female, Caucasian, highly educated and high income earners, and most gardens were located in middle income neighborhoods, with an average of 64 plots, a mean area of half a city block, and a mean age of 10 years. Most Metro Vancouver municipalities had at least one community garden, but no policies in place that were exclusive to community gardening.
Cryptococcus gattii is a human fungal pathogen that emerged on Vancouver Island, BC in 1999. This study aimed to investigate C. gattii survival in composting systems and occupational exposure to C. gattii in work tasks associated with composting. The presence of C. gattii was monitored in composting feedstock and product for one calendar year in a municipal composting facility in Cumberland, BC. Additionally, the survival of an environmental C. gattii isolate was tested in a composting experiment conducted with custom-designed composters that simulated in-vessel composting and home backyard composting. Potential inhalation occupational exposure to C. gattii while performing composting-related tasks were measured during residential yard waste chipping by city workers in Parksville, BC and during the composting experiment where C. gattii contaminated feedstock was composted. C. gattii persisted through three out of five in-vessel composting trials despite high composting temperatures (mean > 60ºC, peak 85ºC) which were achieved evenly throughout the composting material for long periods (> 65 hours). C. gattii was also detected in one out of two yard composting trials after 60 days of composting. The year-long composting feedstock and compost monitoring for C. gattii returned no positive samples. Air sampling during composting-related work tasks found no detectable level of C. gattii. Current composting standard and practice in BC are unlikely to be adequate in eliminating C. gattii from contaminated composting feedstock. Based on the results of this study, the risks of occupational exposure to C. gattii during residential yard waste chipping and composting of contaminated material are low.