To investigate the association between natural landscapes, agricultural uses, and fallowed farmland with coccidioidomycosis incidence in California.
Approach:
Study Design: Population-based study analyzing 65,657 confirmed coccidioidomycosis cases reported to the California Department of Public Health from April 2008 to March 2021.
Data Analysis: Cases linked to annual maps of natural vegetation, agricultural activity, and fallowed land across 20 California counties with high incidence rates.
Key Findings:
Coccidioidomycosis cases increased from 1,708 in 2008 to a peak of 9,778 in 2017.
Incidence was highest in Kern County and generally peaked during the fall.
Larger areas of shrubland, barren ground, and grassland were associated with higher incidence.
Newly fallowed land and land fallowed in the previous 4 years were linked to higher incidence.
Certain agricultural practices, such as grain and hay, were associated with higher incidence, while others like deciduous fruit orchards were linked to lower incidence.
Interpretation:
The study did not confirm the presence of Coccidioides in soils or dust.
Limitations:
The observational nature of the study prevents establishing causation between land use and infections.
Cases were assigned based on residence and diagnosis dates, which may not accurately reflect exposure timing or location.
Surveillance data may underrepresent agricultural workers with limited healthcare access.
