Detection of Airborne <i>Coccidioides</i> Spores Using Lightweight Portable Air Samplers Affixed to Uncrewed Aircraft Systems in California’s Central Valley

Coccidioidomycosis is an emerging fungal infection caused by inhalation of <i>Coccidioides</i> spp. spores. While airborne dispersal is critical to <i>Coccidioides</i> transmission, limited recovery of the pathogen from air has hindered understanding of the aerosolization and transport of spores. Here, we examine uncrewed aircraft systems (UAS) with portable, active air samplers as a novel means of capturing aerosolized <i>Coccidioides</i> and characterizing emissions and exposure risk. We sampled in September 2023 in eastern San Luis Obispo County, California, in an area with confirmed <i>Coccidioides immitis</i> in soils. We completed 41 20 min flights across 14 sites using UAS equipped with an 8 L/min bioaerosol sampler and a low-cost particulate matter sensor. We sampled source soils and air under ambient conditions using one UAS at 1-10 m above ground level, and under a simulated high-dust event using two UAS, one at <2 m height and one at 5-12 m. We detected <i>Coccidioides</i> DNA in 2 of 41 air samples (4.9%), both under ambient conditions at 8 m above ground level, representing the highest known height of airborne <i>Coccidioides</i> detection. Spatially explicit UAS-based sampling could enhance understanding of <i>Coccidioides</i> aerobiology and enable detection in hard-to-reach or hazardous air masses, including dust storms and wildfire smoke.