Infectious Disease Screening and monitoring Research and Innovations

Fallowed Fields Tied to Valley Fever

California surveillance data reveal associations between land use and coccidioidomycosis incidence

09/09/2026 News 3 min read

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Clinical Scorecard: Fallowed Fields Tied to Valley Fever

At a Glance

Category	Detail
Condition	Coccidioidomycosis (Valley Fever)
Key Mechanisms	Inhalation of airborne spores of Coccidioides fungi
Target Population	Residents of California, particularly in areas with high incidence
Care Setting	Population-based study analyzing incidence and environmental factors

Key Highlights

Study analyzed 65,657 confirmed cases of coccidioidomycosis in California from 2008 to 2021
Incidence peaked in Kern County and during the fall season
Higher incidence linked to larger areas of shrubland, barren ground, and grassland
Newly fallowed land associated with increased incidence of coccidioidomycosis
Study did not establish causation between land use and infections

Guideline-Based Recommendations

Diagnosis

Laboratory testing is important to distinguish coccidioidomycosis from other respiratory infections

Management

Consider testing for coccidioidomycosis in patients with compatible respiratory symptoms in high-incidence areas

Monitoring & Follow-up

Surveillance data may underrepresent agricultural workers with limited access to health care

Risks

Environmental factors such as soil conditions and dust production may influence incidence

Patient & Prescribing Data

Patients with respiratory symptoms in California, particularly in high-incidence counties

Study did not assess the performance of any diagnostic method

Clinical Best Practices

Monitor environmental factors that may influence coccidioidomycosis incidence
Utilize geographic and seasonal data to inform testing strategies

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