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Coccidioidomycosis / Valley Fever (Coccidioides spp.)
1996 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 multiple organ systems.

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, diagnosed by chest radiograph
  • 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

  • Cultural, histopathologic, or molecular evidence of presence of Coccidioides immitis, OR
  • Positive serologic test for coccidioidal antibodies in serum or cerebrospinal fluid by:
    • 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, OR
  • Coccidioidal skin-test conversion from negative to positive after onset of clinical signs and symptoms

Case Classification


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