Information for Healthcare Professionals about Valley Fever (Coccidioidomycosis)

Symptomatic persons (40% of cases) usually present 1 to 3 weeks after exposure with fatigue, cough, dyspnea, headache, night sweats, myalgias, and rash. ^1–3 Primary pulmonary disease is often self-limiting, but some patients fail to recover and develop complications or chronic pulmonary disease (approximately 5 to 10% of cases). Disseminated disease occurs in an estimated 1% of cases (higher rates of dissemination are observed in certain risk groups), with bones/joints, soft tissues, and meninges most commonly affected.

Coccidioides immitis (typically in California) and Coccidioides posadasii (typically outside of California).⁴ Clinical differences between the two species have not been observed.

Soil in the southwestern United States, parts of Mexico, and South America. Highly endemic areas include southern Arizona and California’s southern San Joaquin Valley.

Coccidioidomycosis is typically acquired via inhalation of airborne arthroconidia, often after disturbance of contaminated soil (e.g., small-scale activities including construction or excavation, or large-scale events such as dust storms and earthquakes). Primary cutaneous coccidioidomycosis, ⁵ solid organ donor-derived coccidioidomycosis, ⁶ and fomite-transmitted coccidioidomycosis ^7–8 can also occur but are very uncommon.

In persons who develop progressive, chronic, or disseminated disease, symptoms may persist for months or even longer. Meningitis can lead to permanent neurologic damage. Mortality is high in HIV-infected persons with diffuse lung disease.

Serologic tests to detect IgM and IgG antibodies are most often used to diagnose coccidioidomycosis. ⁹ Other methods include culture and microscopy.

• Serology:
  • Enzyme immunoassay (EIA): A very sensitive and commonly used method for diagnosing coccidioidomycosis.. Two EIAs for detection of specific IgM and IgG antibodies against Coccidioides are currently available:
    • Premier ® Coccidioides EIA – Meridian Bioscience, Inc.
    • Enzyme Immunoassay for detection of specific antibodies against Coccidioides spp – Immuno Mycologics, Inc. (IMMY)
  • Immunodiffusion (ID): detects IgM antibodies; positive early in the course of infection.
  • Complement Fixation (CF): detects IgG antibodies and allows for assessment of disease severity.
  • Lateral Flow Assay (LFA): The Sona Coccidioides Antibody LFA (Immuno Mycologics, Inc. [IMMY]) is a rapid test (~30 minutes) to detect the presence of total antibodies against Coccidioides spp (IgM or IgG).
• Culture: Can be performed on tissue and respiratory specimens; however, sputum can be difficult to obtain for culture since patients’ coughs are often non-productive. Processing and manipulation of cultures should be done in a biosafety level 3 laboratory.
• Microscopy: for detection of spherules in tissue or respiratory secretions; low sensitivity.
• Urinary antigen detection: Not widely used, but may have some utility in diagnosing coccidioidomycosis in immunocompromised patients with severe forms of the disease. ¹⁰
• Polymerase Chain Reaction (PCR): A PCR for detection of Coccidioides directly from lower respiratory specimens (GeneSTAT.MDx Coccidioides – DxNA, LLC) has been approved by the Food and Drug Administration. ¹¹ Other PCR tests are still experimental but appear promising. ^12,13

Laboratory culture of Coccidioides immitis

Lung tissue with Coccidioides spherule

No evidence from randomized trials exists to determine whether antifungal treatment for uncomplicated coccidioidal infections reduces symptom duration or prevents complications. Some infections will resolve without antifungal treatment. Infectious Diseases Society of America (IDSA) guidelines suggest treatment for primary pulmonary coccidioidomycosis in patients who:

• Are immunosuppressed 
• Have severe or significantly debilitating illness
• Have diabetes or are frail because of age or comorbidities
• Are pregnant
• Are of African or Filipino ancestry

Disseminated coccidioidomycosis requires antifungal treatment, typically fluconazole or amphotericin B. For more detailed treatment guidelines, please refer to the Infectious Diseases Society of America’s Practice Guidelines for the Treatment of Coccidioidomycosis.

People in endemic areas, particularly those who have occupations or participate in activities exposing them to dust (e.g., construction or agricultural workers, archaeologists, and military trainees). Risk factors for severe or disseminated coccidioidomycosis include African-American race ¹⁴ or Filipino ethnicity, ¹⁵ HIV/AIDS, ¹⁶ use of immunosuppressive medications, ¹⁷ organ transplant, ¹⁸ diabetes mellitus, ¹⁴ or pregnancy. ¹⁹

Coccidioidomycosis is reportable in certain states. Check with your local, state, or territorial public health department for more information about disease reporting requirements and procedures in your area. Click here for coccidioidomycosis statistics.

• Determining the optimal treatment regimen for primary pulmonary coccidioidomycosis
• Identifying host factors associated with increased risk for dissemination in select racial/ethnic groups to target prevention efforts
• Understanding the factors associated with increasing incidence in endemic areas
• Determining the influence of climate change on Coccidioides’ geographic distribution
• Developing improved methods for detection of Coccidioides in environmental samples
• Creating an effective vaccine

• MMWR: Summary of Notifiable Diseases, United States
• Valley Fever Center for Excellence Tutorial for Primary Care Professionals [PDF – 40 Pages]
• The most recent case definition published by the Council of State and Territorial Epidemiologists (CSTE)