Large-Scale Land Development, Fugitive Dust, and Increased Coccidioidomycosis Incidence in the Antelope Valley of California, 1999–2014

Abstract

Ongoing large-scale land development for renewable energy projects in the Antelope Valley, located in the Western Mojave Desert, has been blamed for increased fugitive dust emissions and coccidioidomycosis incidence among the general public in recent years. Soil samples were collected at six sites that were destined for solar farm construction and were analyzed for the presence of the soil-borne fungal pathogen Coccidioides immitis which is endemic to many areas of central and southern California. We used a modified culture-independent nested PCR approach to identify the pathogen in all soil samples and also compared the sampling sites in regard to soil physical and chemical parameters, degree of disturbance, and vegetation. Our results indicated the presence of C. immitis at four of the six sites, predominantly in non-disturbed soils of the Pond-Oban complex, which are characterized by an elevated pH and salt bush communities, but also in grassland characterized by different soil parameters and covered with native and non-native annuals. Overall, we were able to detect the pathogen in 40% of the soil samples (n = 42). Incidence of coccidioidomycosis in the Antelope Valley was positively correlated with land use and particulate matter in the air (PM10) (Pearson correlation coefficient >0.5). With the predicted population growth and ongoing large-scale disturbance of soil in the Antelope Valley in coming years, incidence of coccidioidomycosis will likely further increase if policy makers and land developers continue to ignore the risk of grading land without implementing long-term dust mitigation plans in Environmental Impact Reports.

Expansion of Coccidioidomycosis Endemic Regions in the United States in Response to Climate Change

“…Additionally, Coccidioides spp. may be able to adapt to different soil environments (Colson et al, ). Recognizing that many additional processes contribute to Coccidioides spp.…”

“…Additionally, Coccidioides spp. may be able to adapt to different soil environments (Colson et al, 2017).…”

“…Most soil samples positive for Coccidioides ssp. were collected from the Central Valley of California (Colson et al, 2017;Lauer et al, 2012Lauer et al, , 2014, south-central Arizona (Barker et al, 2012), and Baja Mexico (Baptista-Rosas et al, 2012;Catalán-Dibene et al, 2014;Vargas-Gastélum et al, 2015)-all areas that are hot and dry. Nineteen soil samples positive for Coccidioides ssp.…”

The Powers and Perils of PCR in the Search for the Natural Reservoirs of Coccidioides Species

“…The study by Colson et al [27] expands recent investigations on the molecular identification of Coccidioides in environmental samples with an optimized multiplex PCR method in Bakersfield, California [28], a semi-nested PCR using specific primer in Brazil [29], a nested PCR followed by a diagnostic PCR designed to amplify the internal transcribed spacer (ITS) 2 region in Baja California [30], and an endpoint-nested PCR followed by ITS1 and ITS2 amplification in Dinosaur National Monument, Utah [31]. Thus, there is a volume of rigorous laboratory data that confirm the occurrence of Coccidioides DNA in various locations in the endemic zones.…”

“…A study by Colson et al [27] in this issue of the journal provides a correlation between environment changes due to large-scale land development and the increased incidence of coccidioidomycosis in California. The investigators collected 42 soil samples from six sites destined for solar panel construction in the Antelope Valley of California and used a culture-free, PCR-based approach to test the presence of Coccidioides spp.…”