Blowing in the Wind: Coccidioidomycosis Among Solar Power Farm Construction Workers — California, 2011–2013

Monday, June 23, 2014: 4:00 PM
210, Nashville Convention Center
Jason Wilken , California Department of Public Health, Richmond, CA
Gail Sondermeyer , California Department of Public Health, Richmond, CA
Dennis Shusterman , California Department of Public Health, Richmond, CA
Jennifer McNary , California Department of Public Health, Richmond, CA
Ann McDowell , San Luis Obispo County Public Health, San Luis Obispo, CA
Penny Borenstein , San Luis Obispo County Public Health, San Luis Obispo, CA
Duc Vugia , California Department of Public Health, Richmond, CA
Debra Gilliss , California Department of Public Health, Richmond, CA
Benedict Ancock , California Department of Public Health, Richmond, CA
Janice Prudhomme , California Department of Industrial Relations, Oakland, CA
Deborah Gold , California Department of Industrial Relations, Oakland, CA
Gayle Windham , California Department of Public Health, Richmond, CA
Lauren Lee , California Department of Public Health, Richmond, CA
Byron Robinson , Centers for Disease Control and Prevention, Atlanta, GA
Barbara Materna , California Department of Public Health, Richmond, CA

BACKGROUND:   Coccidioidomycosis, endemic in California, is associated with soil disturbances. Physician occupational illness reports identified coccidioidomycosis among employees constructing 2 solar power-generating facilities in San Luis Obispo County (SLO). We investigated confirmed cases to recommend preventive measures.

METHODS:   A case was defined as clinical- and laboratory-confirmed coccidioidomycosis in an employee of either solar farm after August 2011 and before symptom onset. Patients were interviewed for demographics, missed work days, daily work activities, and protective practices. Hazard ratios for time from employment to symptom onset, adjusted for smoking (aHR), were calculated by Cox proportional hazards regression. Incidence rate (IR)/100,000 population/year was calculated for 1 employer and compared with the SLO IR.

RESULTS:   Of 43 patients, 40 were male and 10 Hispanic; ages ranged from 21 to 63 (median: 47) years. Nine (21%) were hospitalized. Of 42 interviewed, 34 (81%) had missed work (1–547 days; median: 22). The most common occupations were electrician (13), heavy equipment operator (10), and laborer (6). Twenty-one performed soil-disruptive work daily; of these, 6 always used respiratory protection. Fourteen never performed soil-disruptive work. Thirty reported dusty conditions all or the majority of days. Shorter time to symptom onset was associated with performing soil-disruptive work daily (aHR: 4.15; 95% confidence interval [CI]: 1.61–10.67). For 1 employer with 29 patients, IR was 5,342/100,000/year, 139 (95% CI: 86–226) times the SLO IR of 38/100,000/year.

CONCLUSIONS:   Risk for coccidioidomycosis was not limited to employees performing soil-disruptive work at the solar farms; however, daily soil-disruptive work was associated with earlier illness onset. We recommended further limiting dust generation and ensuring access to respiratory protection for all employees, practices the solar farm has reported implementing.