Objective:

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.

Sources:

• Science Advances