Coccidioidomycosis: An Enduring Work-Related Disease

Posted on by Marie A. de Perio, MD; Gregory A. Burr, CIH
A prison located in an arid, hyperendemic area of the Central Valley of California. There is little natural vegetation on the grounds and in the surrounding areas. Photograph by NIOSH.


Coccidioidomycosis, also known as Valley Fever, is a disease caused by the fungus Coccidioides. The fungus grows in the soil in very dry areas. Coccidioidomycosis is endemic (native and common) in the southwestern United States, the Central Valley of California, Mexico, and parts of Central and South America [CDC 2013a]. About 150,000 new infections have been estimated to occur each year in the United States [Galgiani et al. 2005] but only about 22,000 cases were reported in 2011 in the United States. This suggests that the disease is greatly underreported [CDC 2013b]. The apparent incidence of reported coccidioidomycosis increased from 1998 to 2011, from 5.3 cases per 100,000 population in the endemic area (Arizona, California, Nevada, New Mexico, and Utah) in 1998 to 42.6 cases per 100,000 in 2011, although concern has been expressed that some of this increase might be related to changes in surveillance definitions, laboratory practices, and increased awareness leading to increased testing for the disease [CDC 2013b].

Coccidioides is found in soil, commonly about 2–12 inches beneath the surface [Pappagianis 1988; Fisher et al. 2000]. The organisms can be irregularly distributed within a given area. The fungus forms arthrospores, or spores, that can get into the air and travel over long distances when soil is disturbed naturally, such as by wind, or when it is disturbed by human activities such as construction. People can get coccidioidomycosis after inhaling the airborne spores [CDC 2013a]. It has been suggested that human illness could be caused by a single spore [Pappagianis 1988; Galgiani 1993]. The infection cannot be spread from to person to person, or from animals to people. Most people who get the disease live in or visit places where the fungus is in the soil and engage in activities that expose them to soil dust.

Anyone living in an endemic area can be exposed to airborne Coccidiodes spores and thus, is at risk for coccidiodomycosis. Workers in endemic areas who are exposed to dusty conditions related to soil disturbance are thought to be at higher risk for coccidioidomycosis [CDC 2013a; CDPH 2014]. Examples include:

  • Agricultural workers
  • Construction workers
  • Archeological workers
  • Military personnel/trainees
  • Wildland firefighters
  • Workers in mining, gas and oil extraction jobs

About 60% of the people who get coccidioidomycosis infections do not have symptoms [Chiller et al. 2003]. People who do develop symptoms may experience a flu-like illness with fever, cough, headache, rash, and muscle aches that usually resolve without treatment. Some people with severe symptoms may need treatment with anti-fungal therapy [Galgiani et al. 2013]. A small percentage of infected persons (< 1%) may develop widespread disseminated infection, meaning that the infection spreads throughout the body [Chiller et al. 2003]. People at greater risk for developing disseminated infection include people of African American and Asian (particularly Filipino) descent, pregnant women during their third trimester, and immunocompromised persons [CDC 2013a]. Coccidioidomycosis has been shown to be costly and debilitating, with nearly 75% of patients in whom the disease has been recognized missing work or school because of their illness and more than 40% requiring hospitalization [Tsang et al. 2010].

Recent NIOSH Health Hazard Evaluation

In May 2013, the Health Hazard Evaluation (HHE) Program received a request from managers on behalf of employees at two state agencies. They were concerned about exposure of over 2,800 employees to Coccidioides at two state prisons (prison A and prison B) in the Central Valley of California. We visited the prisons in June 2013, interviewed employees about their work practices and exposures, looked at the ventilation system in selected buildings, and met with prison staff to learn about their efforts to reduce dust exposures at work. We also identified laboratory-confirmed cases of coccidioidomycosis among employees from 2009–2013 using annual employee rosters and the California Department of Public Health coccidioidomycosis database. Although not part of this HHE, the Mycotic Diseases Branch in the Centers for Disease Control and Prevention is investigating exposure of prisoners at prison A and prison B to Coccidioides.

More details about the HHE can be found on the NIOSH website.  Key findings included:

  • Both prisons are located in very dry areas where the fungus is endemic.
  • We identified 65 confirmed cases of coccidioidomycosis among prison A employees and calculated a crude average annual incidence of 1,039 cases per 100,000 employees from 2009–2013.
  • We identified 38 confirmed cases among prison B employees and calculated a crude (unadjusted) average annual incidence of 511 cases per 100,000 employees from 2009–2013.
  • Employees may be exposed to Coccidioides at work and outside of work, so we do not know if each confirmed case of coccidioidomycosis was due to an exposure at work or outside of work.
  • Incidence among prison employees appears to be higher than in the county general adult population
  • Efforts to reduce exposure to dust from prison ground sources already included wetting soil before soil-disruption activities, reducing soil disking (shallow plowing), applying a soil stabilizer (a type of soil cement), and planting grass and other vegetation. We were not able to evaluate the effectiveness of these efforts at the prisons.

General recommendations are available for preventing work-related coccidiodomycosis. (See the California Department of Public Health website). In making recommendations for this evaluation, we were faced with uncertainties because the effectiveness of these measures in reducing occupational coccidioidomycosis is unknown. We were left with many questions.

  • Should soil stabilization of prison grounds be continued?
  • At what wind speed should the prison yards be closed?
  • Is there a role for measuring wind speed and doing environmental sampling for Coccidioides?
  • When should respiratory protection be worn by employees? What type of respirator is appropriate?

Seeking Feedback

NIOSH is interested in learning how workplaces in the endemic areas minimize exposures for their employees, including those at increased risk for disseminated infection. Let us know what engineering, administrative, and respiratory protection measures your workplace takes to minimize employee exposures to Coccidioides. We are particularly interested in any evaluation of effectiveness of these efforts.

Marie A. de Perio, MD; Gregory A. Burr, CIH

Dr. de Perio is a medical officer and team leader in the NIOSH Hazard Evaluations and Technical Assistance Branch in the Division of Surveillance, Hazard Evaluations and Field Studies.

Mr. Burr is an Industrial Hygiene Team Leader in the NIOSH Hazard Evaluations and Technical Assistance Branch in the Division of Surveillance, Hazard Evaluations and Field Studies.

Helpful Resources

CDC’s Coccidioidomycosis website

California Department of Public Health’s Preventing Work-Related Valley Fever (Coccidioidomycosis) website

California Department of Public Health’s Preventing Work-Related Coccidioidomycosis (Valley Fever) fact sheet

Arizona Department of Health Services’s Coccidioidomycosis (Valley Fever) website

University of Arizona Center for Excellence’s website     

Morbidity and Mortality Weekly Report, Coccidioidomycosis Among Cast and Crew Members at an Outdoor Television Filming Event — California, 2012


California Department of Public Health  (CDPH) [2014]. Preventing Work-Related Valley Fever (Coccidioidomycosis) []. Date accessed: March 2014.

Centers for Disease Control and Prevention (CDC) [2013a]. Coccidioidomycosis. []. Date accessed: March 2014.

Centers for Disease Control and Prevention (CDC) [2013b]. Increase in reported coccidioidomycosis —United States, 1998–2011. MMWR 62(12):217–221.

Centers for Disease Control and Prevention (CDC) [2014]. CDC health information for international travel 2014. New York: Oxford University Press.

Chiller TM, Galgiani JN, Stevens DA [2003]. Coccidioidomycosis. Infect Dis Clin N Am 17(1):41–57.

Fisher F, Bultman MW, Pappagianis D [2000]. Operational guidelines for geological fieldwork in areas endemic for coccidioidomycosis (valley fever). U.S. Geological Survey Open-File Report; U.S. Department of the Interior: Washington, DC, pp. 1–6.

Galgiani JN [1993]. Coccidioidomycosis. West J Med 159(4):153–171.

Galgiani JN, Ampel NM, Blair JE, Catanzaro A, Johnson RH, Stevens DA, Williams PL [2005]. Coccidioidomycosis. Clin Infect Dis 41(9):1217−1223.

Pappagianis D [1988]. Epidemiology of coccidioidomycosis. Curr Top Med Mycol 2:199–238.

Tsang CA, Anderson SM, Imholte SB, Erhart LM, Chen S, Park BJ, Christ C, Komatsu KK, Chiller T, Sunenshine RH [2010]. Enhanced surveillance of coccidioidomycosis, Arizona, USA, 2007–2008. Emerg Infect Dis 16(11):1738–1744.

Posted on by Marie A. de Perio, MD; Gregory A. Burr, CIH

10 comments on “Coccidioidomycosis: An Enduring Work-Related Disease”

Comments listed below are posted by individuals not associated with CDC, unless otherwise stated. These comments do not represent the official views of CDC, and CDC does not guarantee that any information posted by individuals on this site is correct, and disclaims any liability for any loss or damage resulting from reliance on any such information. Read more about our comment policy ».

    I was infected with coccidioidomycosis –what I went through with this to recover, lets just say it was horrible and I was one of the lucky ones that wasn’t able to recover without anti-fungal therapy.

    Anyway, I made it through the treatment and can relate to a lot that was said here and yes I caught this at a construction site.
    My company was asked to do another bid for a contractor after completing one of their jobs in Alaska.

    I flew to Scottsdale, Arizona and just walked on the job site and boom, the next day it hit me like a ton of bricks. After I was better the doctors told me that I could get a recurrence of this in about 10 years, do you know if this is true?

    I’m definitely going to be following this site a lot more and will tell my employees as well. Anything that goes in your lungs is completely miserable and life threatening.

    This was very interesting to see.

    Thank you for your interest in our blog and our work. Usually, life-time immunity is acquired after an infection, which means people don’t get it again. However, occasionally, reactivation or relapse of a prior infection is possible, especially when there are changes in a person’s immune system brought about by other diseases or medications.

    We’ll soon have another tool to use in our attempts to protect workers. I learned at the CSG that Nielsen Biosciences should be marketing their cocci skin testing product; they decided to pay the licensing fee. It occurs to me that we should begin to consider how this tool might be used. I don’t know, for example, if an employer could preferentially hire only skin test reactive workers. For that matter, I don’t know if there would be an adequate pool of skin test reactors. I can make a case for the use of the test for assessing worker acquisition of the fungus. This should provide a better means of assessing the effectiveness of our prevention interventions. (I think it would also be a benefit to workers even if asymptomatic. A small proportion of them may develop disseminated disease despite their not having any signs/symptoms of primary illness.)

    Thank you for your interest in this blog. We agree that the coccioidoidal spherulin skin test may have some valuable applications to worker populations such as in baseline testing to help a worker evaluate his or her personal risk for disease. We comment on its potential use in our final HHE report on p. 22-23 ( ) and include some points to consider when exploring use of this test.

    Great & very informative blog. Infection could be skin also caused by bacteria or fungal. Take care of skin by using best antibacterial, antifungal soap for bath and hand wash.

    I am very much impressed from your post.It has amazing information.I learned lot of new things which explores my knowledge in various developments.So i must appreciate your efforts on posting these information.

    God bless all of them who suffer from these sort diseases but there should be perfect precautions and if any one knows that i am gonna suffer from this thing then why he got himself near to that thing he should have to get far from this thing….

    What is the actual test for this fungus? How would you go about getting the test done if you suspected it might be something you’re suffering from?

    I started having eye issues in 2013 and in April 2014 my body broke down and my eye felt like it was going to pop. Up until this time My eye doctors tested me for everything they could think of and ultimately took a biopsy of my eye in April 2014 as well. The samples came back positive for COCCI. The only place I could have gotten it was West Texas while traveling for business. After 5 months of flucanozale and injections to revive my eye I elected to have it removed to end the pain. My eye was sent to a university for pathology and there was two colonies of cocci in my eye that did tremendous damage to it beyond repair and this could not be detected by slit lamps or ultrasounds. I am in the process of filing workers comp and accidental eye loss through work insurance. Hope my eye can help VF victims and help alert eye professionals to start considering the SW US a danger zone for traveling.

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Page last reviewed: December 7, 2016
Page last updated: December 7, 2016