Molecular detection of Coccidioides sp. spores in arid soils and UAS-enabled bioaerosol collection in the San Joaquin Valley, 2024

The goal of this study is to determine if there is an association between aerosolized particulate matter (PM) density, wind speed, temperature, humidity, soil-specific parameters, or other site-specific conditions and Coccidioides detection to better understand fungal spore dispersal within the San Joaquin Valley, CA. Soil and filter samples were concurrently collected using an uncrewed aircraft system (UAS) equipped with bioaerosol samplers flown synchronously at multiple heights. Samples were assessed for the presence of Coccidioides spores per the cocciENV assay (Bowers et al, 2019). Collection sites included Bakersfield, CA and surrounding Kern County (39 total), with 767 samples collected using an interrupted radial transect design.

Impact/Purpose

Coccidioidomycosis (colloquially “Valley Fever”) is an emerging fungal infection caused by inhalation of airborne Coccidioides spores. While Coccidioides sp. have been detected in soils across California, successful recovery of spores from airborne samples have been limited, hindering our understanding of the environmental factors that give rise to their dispersal. This data represents the molecular detection (qPCR) of fungal spores from multi-institutional, multi-seasonal sampling campaigns using soil and bioaerosol samples from unmanned aircraft systems (UAS).

Citation

Bistolas, K., J. Reichman, AND J. Markwiese. Molecular detection of Coccidioides sp. spores in arid soils and UAS-enabled bioaerosol collection in the San Joaquin Valley, 2024. U.S. Environmental Protection Agency, Washington, DC, 2025. [DOI: 10.23719/1532240]

DOI: Molecular detection of Coccidioides sp. spores in arid soils and UAS-enabled bioaerosol collection in the San Joaquin Valley, 2024