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Indoor fungal communities: associations with indoor environmental conditions and asthma outcomes

Cochran, Samuel J
http://orcid.org/0000-0001-7314-4265
http://rave.ohiolink.edu/etdc/view?acc_num=osu1658405904721812

Abstract Details

2022, Doctor of Philosophy, Ohio State University, Environmental Science.
We spend 90% of our time indoors where we are exposed to diverse microbial communities which can have profound effects on human health outcomes. Advances in DNA-based technologies offer greater ability to quantitatively measure indoor fungal communities and more accurately assess the influence of environmental conditions on fungal communities as well as the influence of fungal exposures on health. Trends are emerging in our understanding of pathways between built environments, indoor microbiomes, and ultimately human health, but much remains uncertain. Fungal diversity is consistently and inversely associated with development of asthma and allergic disease. Further, seasonal variation in asthma and allergy is well established. So too is the relationship between asthma development and sensitization to select allergenic fungi. However, the influence of fungal exposures—including diversity, total fungal concentration, and select fungal taxa—on measures of asthma morbidity is still not well understood. The influence of season and other indoor environmental conditions or occupant behaviors in shaping these measures of fungal exposure is also understudied. The goal of this work is to investigate novel associations between measures of childhood asthma morbidity and fungal exposures, and to examine the effect of comprehensive occupant behaviors and indoor environmental characteristics—including conditions mediated by season—on indoor fungal communities. Bedroom floor dust samples were collected from two cohorts: the New York City Neighborhood Asthma and Allergy Study (NAAS) and the Columbia Children’s Center Environmental Health (CCCEH) birth cohort. DNA extracted from floor dust samples was analyzed using quantitative polymerase chain reaction and next-generation sequencing in order to obtain total fungal concentration, fungal diversity metrics, and concentration of individual fungal taxa. Fungal diversity was significantly and inversely associated with asthma symptom frequency and asthma symptom persistence in the NAAS cohort. Total fungal concentration and concentrations of individual fungi were not significantly associated. However, total fungal concentration and concentration of summed allergenic fungi varied significantly by season, peaking in spring and coincident with springtime peaks in pediatric asthma exacerbation reported elsewhere. Spring also represented the season with the highest indoor temperature and relative humidity, which likely mediate the association between season and fungal concentration. Similarly, among CCCEH homes, structural and behavioral factors associated with increased indoor moisture content, such as humidifier use or wet mopping, were associated with higher concentrations of A. alternata and related fungi known to produce the asthma-associated allergen, Alt a 1. In contrast, presence of bedroom carpeting and regular cleaning with a vacuum were associated with greater fungal diversity, which is protective against asthma morbidity. This dissertation presents a comprehensive examination of indoor environmental conditions and season effects in association with clinically relevant fungal taxa as well as fungal community composition and concentration, identifying moisture content as one important mediating variable. Further, fungal exposures are examined alongside previously understudied measures of asthma morbidity, highlighting the protective effect of high levels of indoor fungal diversity. Further research is needed to examine the role of seasonal fungal exposures and asthma morbidity as well as the efficacy of select intervention strategies aimed at reducing harmful fungal exposures indoors.
Karen Dannemiller, PhD (Advisor)
Jeffrey Bielicki, PhD (Committee Member)
Jiyoung Lee, PhD (Committee Member)
Virginia Rich, PhD (Committee Member)
Matthew Perzanowski, PhD (Committee Member)
176 p.
Environmental Health; Microbiology
Indoor fungal communities; built-environment; house-dust; asthma; DNA; qPCR;

Recommended Citations

Citations

  • Cochran, S. J. (2022). Indoor fungal communities: associations with indoor environmental conditions and asthma outcomes [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1658405904721812

    APA Style (7th edition)

  • Cochran, Samuel. Indoor fungal communities: associations with indoor environmental conditions and asthma outcomes. 2022. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1658405904721812.

    MLA Style (8th edition)

  • Cochran, Samuel. "Indoor fungal communities: associations with indoor environmental conditions and asthma outcomes." Doctoral dissertation, Ohio State University, 2022. http://rave.ohiolink.edu/etdc/view?acc_num=osu1658405904721812

    Chicago Manual of Style (17th edition)

osu1658405904721812
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This open access ETD is published by The Ohio State University and OhioLINK.