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Coccidioidomycosis / Valley Fever (Coccidioides spp.)
1995 Case Definition

Clinical Description

Infection may be asymptomatic or may produce an acute or chronic disease. Although the disease initially resembles an influenza-like febrile illness primarily involving the bronchopulmonary system, dissemination can occur to virtually any organ system. Confirmation of coccidioidomycosis requires the demonstrated presence of Coccidioides immitis by histopathologic, cultural, or molecular means; and/or demonstration of a specific immunologic response (i.e., skin test conversion or demonstration of presence of coccidioidal antibody). The results of these immunologic tests must be interpreted in the context of the varied clinical presentations and the duration and clinical type of coccidioidomycosis.

Clinical Criteria

An illness characterized by one or more of the following:

  • Influenza-like signs and symptoms (e.g., fever, chest pain, cough, myalgia, arthralgia, and headache)
  • Pneumonia or other pulmonary lesion, by chest X-ray
  • Erythema nodosum or erythema multiforme rash
  • Involvement of bones, joints, or skin by dissemination
  • Meningitis
  • Involvement of viscera and lymph nodes

Laboratory Criteria for Diagnosis

Laboratory-confirmed coccidioidomycosis requires one or more of the following:

  • Cultural, histopathologic, or molecular evidence of presence of C. immitis, OR
  • Immunologic evidence of infection:
    • Serologic (testing of serum, cerebrospinal fluid, or other body fluid):
      • Detection of coccidioidal Immunoglobulin M (IgM) by immunodiffusion, enzyme immunoassay (EIA), latex agglutination, or tube precipitin, OR
      • Detection of rising titer of coccidioidal Immunoglobulin G (IgG) by immunodiffusion, EIA, or complement fixation.
    • Coccidioidal skin test conversion from negative to positive after the onset of clinical signs and symptoms.

Case Classification


A case that meets the clinical criteria and is laboratory confirmed.