Surveillance of Coccidioides in Aerosols in Arizona

AMELIA STOUT, Marieke L. Ramsey, Daniel R. Kollath, Megan C. Ruby, Bridget M. Barker, Pierre Herckes, Matthew Fraser, Arizona State University

     Abstract Number: 490
     Working Group: Bioaerosols in Agriculture: Sources, Risks and Mitigation

Abstract
Valley fever is an infection caused by the fungus Coccidioides in the lungs. Valley fever can cause many acute health problems in humans and animals, such as fatigue, cough, and shortness of breath, and in severe cases, can even cause long-term problems with the lungs and nervous system. To date, nearly all of the research on Coccidioides has been based on clinical studies. This study looks at the presence of Coccidioides in the air, soil, and burrow systems at a site in Mesa, Arizona. The primary transport mechanism of Valley Fever into humans is inhalation of the fungus through aerosol dust. The focus of this presentation will be on the aerosol samples collected during the first year of sampling. Aerosol samples were collected for 24 hours every 6 days, following the Environmental Protection Agency sampling schedule. Quartz fiber filters were used to determine PM10, key ions, and organic and elemental carbon. Cellulose filters were used to analyze key elements. Gravimetric mass was determined to quantify the total amount of PM10. Ion chromatography was used to determine concentrations of key ions on quartz fiber filters. Organic carbon and elemental carbon were quantified by thermal optical absorption. Key elements were analyzed by hydrofluoric acid digestion followed by ICP-MS. Coccidioides were detected frequently in the air. The detection was more likely to occur during high PM10 days. Overall PM10 concentrations at the site were low for the region. The chemical measurements showed little anthropogenic impact. The chemistry will be discussed relative to the detection of Coccidioides. This study aims to deepen the understanding of the presence and transport of Valley fever in the desert southwest.