Top 5 Takeaways

  1. Outbreak Identification: The California Department of Forestry and Fire Protection (CAL FIRE) reported a coccidioidomycosis outbreak among 7 wildland firefighters from two crews exposed near the Tehachapi Mountains in June 2021, with 3 cases confirmed through laboratory tests.
  2. Risk Factors and Exposure: Confirmed cases were associated with working in dusty conditions without respiratory protection. All confirmed cases were from crew B, with an attack rate of 14.3%.
  3. Demographics and Impact: Affected individuals were men aged 25–34, including two of Hispanic or Latino ethnicity. Hospital stays ranged from 8 to 17 days, highlighting the severity in certain cases.
  4. Preventative Measures and Recommendations: Despite challenges, the need for respiratory protection and training on coccidioidomycosis exposure risks is emphasized. CAL FIRE and CDPH recommend safety briefings and training for firefighters.
  5. Importance of Early Detection: Early recognition and management of coccidioidomycosis are crucial. CAL FIRE’s proactive approach led to quicker diagnoses compared to previous reports, showcasing the benefits of awareness and prompt testing.

Original Article Author and Citation

Corresponding Author

Marisa A. P. Donnelly,

Suggested Citation

Donnelly MA, Maffei D, Sondermeyer Cooksey GL, et al. Notes From the Field: Coccidioidomycosis Outbreak Among Wildland Firefighters — California, 2021. MMWR Morb Mortal Wkly Rep 2022;71:1095–1096. DOI:


This MMWR report describes an outbreak of coccidioidomycosis, or Valley Fever, among California wildland firefighters in 2021. The outbreak was identified after several firefighters experienced respiratory symptoms following their work on wildfires in a region known for high incidence of the disease. The report underscores the challenges of using respiratory protection in the demanding conditions of wildland firefighting but stresses its importance for prevention, alongside training and early detection strategies.


The investigation included notifications from CAL FIRE to the California Department of Public Health (CDPH), interviews with the affected individuals, review of medical records, and serologic testing to confirm coccidioidomycosis cases. The focus was on identifying exposure risks, the attack rate within the crews, and the efficacy of early detection and management strategies.


The report discusses the endemic nature of Coccidioides spp. in certain U.S. regions and the occupational risk to firefighters due to dust exposure. It highlights the need for improved protective measures and training to mitigate risks, as well as the importance of healthcare providers in recognizing potential cases of coccidioidomycosis, especially in the context of similar symptoms to COVID-19.


As wildfires and the frequency of coccidioidomycosis increase in California, the report calls for further exploration of protective equipment and enhanced training for wildland firefighters. Early diagnosis and treatment are essential in managing the disease and preventing severe outcomes.

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